CN107996122A

CN107996122A - Grass-mowing machine and its line-putting method

Info

Publication number: CN107996122A
Application number: CN201610970415.0A
Authority: CN
Inventors: 钱富; 邵陈蔚; 刘芳世; 牟国良; 张士松
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: Positec Power Tools Suzhou Co Ltd
Priority date: 2016-10-28
Filing date: 2016-10-28
Publication date: 2018-05-08
Also published as: WO2018077231A1

Abstract

The present invention provides a kind of line-putting method of grass-mowing machine and grass-mowing machine, including：Extension rod；Casing, arranged on described extension rod one end；Moving head, is connected on the casing, has line outlet；Motor, drives the moving head to enclose and rotates about the axis；Beat the grass line, stretched out by the line outlet, the length of stretching is length of beating the grass；Payingoff mechanism, can selectively discharge the line of beating the grass, length of beating the grass described in increase；Detection module, when the grass-mowing machine carries out cutting work, the special parameter for length of beating the grass described in the detection module detection reflection；Controller, for by the special parameter compared with parameter preset, and then export comparative result；The payingoff mechanism is according to the comparative result selective actuation with line of beating the grass described in discharging.Operator need not interrupt the work of grass-mowing machine during the work time, can realize unwrapping wire automatically, without manual operation and unwrapping wire it is reliable.

Description

Grass trimmer and paying-off method thereof

Technical Field

The invention relates to a garden tool, in particular to a grass trimmer and a paying-off method of the grass trimmer.

Background

The green vegetation is an environmental factor indispensable to human beings, and the consciousness of greening is more and more deep into the mind. The green turf is ubiquitous in the courtyards of golf courses, football fields, manholes and villas and common residential districts, and vitality are brought to the lives of people. But if left from the care of the person, these sods become bumpy and disorganized.

Grass trimmers are gaining favor from more and more users as a garden tool for trimming turf. The grass trimmer is generally driven to rotate to trim grass, the grass trimming line is arranged in the working head and extends out of a free tail end, and the free tail end rotates and cuts along with the high-speed rotation of the grass trimming head. The grass mowing line rotates to grass, so that the tail end of the grass mowing line is easy to wear, the worn grass mowing line cannot reach the required grass mowing radius, and the grass mowing efficiency is greatly reduced. Therefore, the line releasing mechanism is required to be arranged on the grass trimmer so as to adjust the length of the grass trimming line extending out of the grass trimming head at a proper time.

The general pay-off mechanism has two kinds, one kind is the automatic pay-off mechanism of switching on and shutting down, as the name suggests, the automatic pay-off of all can all be opened the line when opening at every turn and shutting down to the pay-off mechanism of switching on and shutting down, need not extra operation, but because the line all can be unwrapped wire at every turn opening and shutting down, the line loss of beating grass is more serious. The other type is a knocking pay-off mechanism which is provided with a trigger part protruding out of a cover, when the knocking pay-off mechanism is used, the cover is knocked on the ground to enable the trigger part to trigger the pay-off, and the knocking pay-off mechanism has the main defects that when the grass trimmer is used for trimming, the grass trimmer needs to be reversed to enable the cover to knock the ground to pay off, so that the trimming and grass mowing work needs to be interrupted, and the operation is complicated.

The other is a grass trimmer, wherein a paying-off switch is independently arranged at a handle to control a paying-off mechanism, when a user senses that the grass trimming line is worn to cause low grass trimming efficiency, the paying-off switch is pressed down, the paying-off mechanism executes paying-off action, and a section of grass trimming line is paid off. The grass trimmer with the structure needs manual operation, and a user needs to judge the paying-off time according to the state of the grass trimmer.

In addition, the grass trimmer can realize paying off without the operation of a user, an intelligent paying-off control mechanism is adopted, and the paying-off device which is balanced with the centrifugal force of the grass trimming line with the set length during normal work is arranged on the grass trimming head, so that when the grass trimming line is worn, the paying-off device acts to pay off a section of fiber line. Though the grass trimmer with the structure does not need manual operation, the precision requirement on the pay-off device is quite high, and the pay-off is unreliable.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide the automatic paying-off grass trimmer with reliable paying-off.

In order to solve the problems, the technical scheme of the invention is as follows: a lawnmower comprising: an extension rod; the shell is arranged at one end of the extension rod; the grass cutting head is connected to the shell and is provided with a wire outlet; a motor for driving the grass cutting head to rotate around an axis; the grass mowing line extends out of the line outlet, and the extending length is the grass mowing length; the paying-off mechanism can selectively release the grass mowing line and increase the grass mowing length; the detection module detects a specific parameter reflecting the grass mowing length when the grass mowing machine performs cutting work; the controller is used for comparing the specific parameter with a preset parameter and further outputting a comparison result; and the paying-off mechanism is selectively started according to the comparison result so as to release the grass mowing line.

Preferably, the specific parameter is a parameter reflecting a workload.

Preferably, the specific parameter comprises the working current of the grass trimmer, and the preset parameter comprises a preset current value.

Specifically, the controller compares the working current with the preset current value, and if the working current is smaller than the preset current value, the controller outputs a control signal to start the paying-off mechanism to release the grass mowing line.

Preferably, the parameter detected by the detection module further includes a voltage, and the controller calculates the preset current value through the voltage.

In another alternative embodiment, the specific parameter includes a rotational speed of the motor, and the preset parameter includes a preset motor rotational speed value.

Specifically, the controller compares the rotating speed detected by the detection module with the preset motor rotating speed value, and if the detected rotating speed is greater than the preset motor rotating speed value, the controller outputs a control signal to start the pay-off mechanism to release the grass mowing line.

Preferably, the parameter detected by the detection module further includes a voltage, and the controller calculates the preset motor rotation speed value through the voltage.

Preferably, the specific parameter is a parameter reflecting an actual physical length of the grass mowing length.

Specifically, the specific parameter comprises air pressure near the tail end of the grass mowing length, and the detection module comprises an air pressure parameter detection module for detecting air pressure changes caused by different grass mowing lengths.

Preferably, the controller compares the air pressure value detected by the detection module with a preset air pressure value, and if the detected air pressure value is greater than the preset air pressure value, the controller outputs a control signal to start the pay-off mechanism to release the mowing line.

In another alternative embodiment, the detection module comprises at least one pair of photocells, one of which is intended to emit an opto-electronic signal and the other of which is intended to receive an opto-electronic signal, the grass cord being able to influence the reception of said opto-electronic signal.

A lawnmower according to claim 12, wherein: the photoelectric elements are arranged at intervals, the interval is used for the tail end of the grass mowing length to pass through when the grass mowing machine works, when the tail end passes through the interval, the photoelectric signal is cut off, the photoelectric element used for receiving the photoelectric signal does not receive the photoelectric signal any more, and the controller outputs a control signal to start the paying-off mechanism according to the signal of the photoelectric element.

Specifically, the photoelectric elements are arranged at intervals, the interval is used for the tail end of the grass mowing length to pass through when the grass mowing machine works, when the tail end passes through the interval, the photoelectric signal is reflected, the photoelectric element used for receiving the photoelectric signal receives the reflected photoelectric signal, the controller identifies the signal of the photoelectric element, and outputs a control signal to start the pay-off mechanism.

The invention also provides an optional implementation scheme, the detection module comprises a Hall sensor, the grass mowing line has magnetism, when the grass mowing line passes through the sensing range of the Hall sensor, the Hall sensor senses the magnetism of the grass mowing line, when the grass mowing line is abraded to reach or exceed a set length, the Hall sensor cannot detect the magnetism signal of the grass mowing line, and the controller outputs a control signal to start the paying-off mechanism according to the signal of the Hall sensor.

The invention also provides an optional implementation scheme, the detection module comprises a color recognition sensor, the color recognition sensor can recognize the color of the grass mowing line, when the grass mowing line is worn to reach or exceed a set length, the color recognition sensor cannot recognize the color of the grass mowing line, and the controller outputs a control signal to start the paying-off mechanism according to the signal of the color recognition sensor.

Preferably, the paying-off mechanism comprises at least one paying-off electronic switch, and the paying-off electronic switch can selectively start the paying-off mechanism according to the comparison result.

Preferably, the pay-off mechanism is selectively started according to the comparison result to release the grass mowing line, so that the grass mowing length is increased to a target length, the detection module further detects a parameter reflecting whether the grass mowing length reaches the target length, and the controller outputs a control signal according to the parameter reflecting whether the grass mowing length reaches the target length to selectively stop the pay-off action of the pay-off mechanism.

Preferably, for each comparison result, the pay-off mechanism executes a pay-off action at most once.

Preferably, the grass trimmer further comprises an adjusting mechanism with preset parameters, and the preset parameters can be adjusted through the adjusting mechanism.

Preferably, the pay-off mechanism further comprises a control device, the control device comprises a control circuit electrically connected with the motor, and the control circuit is used for controlling the motor to switch between a normal working speed and a pay-off speed.

The invention also provides a line releasing method of the grass trimmer, which comprises the following steps:

s1: detecting a specific parameter reflecting the grass mowing length;

s2: comparing the specific parameter with a preset parameter, and outputting a comparison result;

s3: and selectively starting the pay-off mechanism to release the grass mowing line according to the judgment result of the step S2.

Preferably, the specific parameter detected in step S1 is a parameter reflecting a workload.

In a preferred embodiment, if the specific parameter detected in step S1 includes a working current of the lawn mower, and the preset parameter includes a preset current value, the controller compares the working current with the preset current value, and if the working current is smaller than the preset current value, the paying-off mechanism is activated to release the lawn mowing line in step S3.

Preferably, if the parameter detected by the detection module in the step S1 further includes a voltage, the controller calculates the corresponding preset current value according to the voltage.

In another optional implementation, if the specific parameter detected in step S1 includes the rotation speed of the motor, and the preset parameter includes a preset motor rotation speed value, the rotation speed is compared with the preset motor rotation speed, and if the rotation speed is greater than the preset motor rotation speed, the paying-off mechanism is activated in step S3 to release the mowing line.

Preferably, the specific parameter detected in step S1 is a parameter reflecting the actual physical length of the grass length.

In a preferred embodiment, if the specific parameter detected in step S1 includes a photoelectric signal, and the preset parameter includes a preset photoelectric signal indicating that the grass cutting length is not worn or worn to a preset length, the photoelectric signal is compared with the preset photoelectric signal, and if the photoelectric signal is different from the preset photoelectric signal, the paying-off mechanism is activated to release the grass cutting line in step S3.

In another preferred embodiment, if the specific parameter detected in step S1 includes a photoelectric signal, and the preset parameter includes a preset photoelectric signal indicating that the grass length has been worn to reach or exceed a preset length, the photoelectric signal is compared with the preset photoelectric signal, and if the preset photoelectric signal is the same as the preset photoelectric signal, the paying-off mechanism is activated to release the grass line in step S3.

Compared with the prior art, the grass trimmer comprises the pay-off mechanism, the pay-off mechanism is controlled by the controller which is independently arranged, the controller automatically outputs a control result according to the parameters detected by the detection module to selectively control the action of the pay-off electronic switch, so that the pay-off control mechanism is started, manual operation is not needed, the pay-off is more intelligent, the pay-off is controlled by detecting specific parameters, the reliability of the pay-off mechanism is greatly improved, and the loss of a grass trimming line is reduced.

Drawings

The invention is further described with reference to the following figures and embodiments.

FIG. 1 is a cross-sectional view of a lawn mower according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the head of the lawnmower shown in FIG. 1.

FIG. 3 is a schematic view of a line-releasing control principle module of the grass trimmer shown in FIG. 1.

Fig. 4 to 6 are schematic diagrams of the operation of the control circuit of the grass trimmer shown in fig. 1.

FIG. 7 is a schematic view of the change in the rotational speed of the motor of the lawnmower shown in FIG. 1.

Fig. 8 to 12 are schematic views of the state change process of the slide block and the wire coil in the paying-off process controlled by the paying-off mechanism of the grass trimmer shown in fig. 1.

FIG. 13 is an exploded perspective view of the thread take-up mechanism in the head of the lawnmower shown in FIG. 1.

FIGS. 14-16 are schematic views illustrating the state change process of the slider and the stopping device in the line laying mechanism of the lawn mower shown in FIG. 1 during line laying controlled by the line laying mechanism.

FIG. 17 is a schematic view of the process of controlling the pay-off of the pay-off mechanism of FIG. 1.

FIG. 18 is a schematic circuit diagram of the pay-off control of the lawnmower shown in FIG. 1.

FIG. 19 is a flow chart illustrating the line-feeding control of the lawnmower according to the second embodiment of the present invention.

FIG. 20 is an enlarged cross-sectional view of a head of a lawnmower according to a third embodiment of the present invention.

FIG. 21 is a schematic view of the pay-off mechanism of the lawnmower shown in FIG. 20 controlling the pay-off process.

FIGS. 22 and 23 are schematic views of the relative positional relationship of the photocell and the grass cutting head of the lawnmower shown in FIG. 20.

FIG. 24 is an enlarged cross-sectional view of a head of a lawnmower according to a fourth embodiment of the present invention.

FIG. 25 is a schematic view of the pay-off mechanism of the lawnmower shown in FIG. 24 controlling the pay-off process.

FIG. 26 is a bottom view of a head of a lawnmower according to a fifth embodiment of the present invention.

FIG. 27 is a schematic view of the pay-off mechanism of the lawnmower shown in FIG. 26 illustrating the flow of control for paying off the wire.

FIG. 28 is a schematic view illustrating a process of controlling paying-off by the paying-off mechanism of the grass trimmer according to the sixth embodiment of the present invention.

FIG. 29 is an enlarged cross-sectional view of a head of a lawnmower according to a seventh embodiment of the present invention.

FIG. 30 is a schematic view of the pay-off mechanism of the lawnmower shown in FIG. 29 illustrating the process of controlling the pay-off.

FIG. 31 is an enlarged cross-sectional view of a head of a lawnmower according to an eighth embodiment of the present invention.

FIG. 32 is a schematic view of the pay-off mechanism of the lawnmower shown in FIG. 31 illustrating the process of controlling the pay-off.

FIG. 33 is a schematic flow chart of a line laying method of the grass trimmer according to the present invention.

Wherein,

resetting device for slider 405 of 100 grass trimmer 33

20 first end of first toothed edge 411 of extension rod 39

22 the second tooth 409 mounting part of the grass-mowing head 65

24 auxiliary handle 45 radial surface 407 stop boss

23 main handle 67 third tooth 413 second end

25 first tooth 417 abutting part of housing 63

26 motor 69 fourth tooth 415 hollow

21 detection module 37 tooth-shaped groove 101 photoelectric element

51 controller 200 grass trimmer 103 air pressure sensor

27 main switch 300 grass trimmer 105 Hall sensor

28-accommodating seat 400 grass trimmer 102 vibration sensor

38 battery package 47 circumferential surface 31 broken string blade

30-cover 49 protruding tooth 500 grass mower

32-spool 54 biasing member 600 grass trimmer

34 line 401 of beating grass backstop 106 colour recognition sensor

34a free end 403 stop

Detailed Description

Fig. 1 to 18 show a lawnmower 100 according to a first embodiment of the present invention.

Referring to fig. 1, the grass trimmer 100 of the present embodiment includes an elongated rod 20 extending lengthwise, a head mounted on one end of the elongated rod 20, the head includes a housing 25, a motor 26 mounted in the housing 25, a grass trimmer head 22 driven by the motor 26 to rotate around an axis L, and a battery pack 38 for powering the motor 26; the grass trimmer 100 also comprises a main handle 23 and an auxiliary handle 24 which are arranged on the extension rod 20 and are arranged at a certain distance from the machine head, a main switch 27 for controlling the motor, and a grass cutting line for cutting. The grass cutting head 22 also comprises a line outlet hole, the free tail end 34a of the grass cutting line 34 extends out of the line outlet hole of the grass cutting head 22, and the cutting length of the grass cutting machine during working is the grass cutting length. The grass trimmer also comprises a pay-off mechanism for controlling the paying-off, a detection module for detecting specific parameters reflecting the grass trimming length and a controller for controlling the pay-off mechanism. In the working process of the grass trimmer, the paying-off mechanism can be selectively started according to a control signal output by the controller to release the grass trimming line, so that the grass trimming length is increased.

Specifically, the detection module detects a specific parameter reflecting the grass mowing length, and a direct method is to detect the change of centrifugal force, the change of current, the change of output power and the change of rotating speed.

Specifically, the controller stores preset parameters, the controller compares the specific parameters which reflect the grass mowing length and are detected by the detection module with the preset parameters, and then outputs a comparison result, the comparison result is used as a control signal for controlling the pay-off mechanism by the controller, and the pay-off mechanism is selectively started according to the comparison result to release the grass mowing line. The whole paying-off process does not need manual operation and is more intelligent.

Specifically, when the grass trimmer normally works, the main switch 27 is started, the motor is powered on, the grass trimming head 22 is driven by the motor 26 to rotate around the circumference L, the free tail end 34a of the grass trimming line 34 rotates to form a cutting surface, and a user lifts the grass trimmer 100 through the handle to enable the grass trimming line 34 to cut grass along the cutting surface formed by the rotation of the grass trimming line. The grass trimmer 100 can be switched between a grass trimming state in which the free end 34a of the grass line 34 rotates horizontally and a trimming state in which the free end rotates vertically to meet different cutting requirements.

The grip portion of the handle refers to a portion of the handle that is gripped by the hand of the operator. Referring to fig. 1, in the present embodiment, the handle includes a main handle 23 and an auxiliary handle 24 disposed at a certain distance, and a main switch 27 is disposed on the main handle 23. So arranged, the operator can more reliably lift and operate the grass trimmer through the main handle 23 and the auxiliary handle 24.

In this embodiment, the motor 26 for driving the grass-mowing head 22 is coaxial with the grass-mowing head 22, and preferably, the output shaft of the motor 26 directly drives the grass-mowing head 22, that is, the rotating shaft of the grass-mowing head 22 is the motor shaft of the motor 26, that is, the output shaft, and the structure is simple and compact. It will be appreciated by those skilled in the art that the motor 26 may be disposed anywhere else in the extension rod 20 and drive the rotation of the grass-mowing head 22 through a particular transmission mechanism.

For convenience of description, the terms "axial," "circumferential," and other orientation-related descriptions of this specification refer to the axis of rotation of the grass-mowing head 22. Such as "axial" is the direction of extension along the axis of rotation of the grass-mowing head 22; "circumferential" is the direction about the axis of rotation of the grass-mowing head 22.

Referring to fig. 1 and 2, the grass-mowing head 22 comprises a receiving seat 28, a cover 30 coupled with the receiving seat 28, and a wire coil 32 disposed in an inner cavity formed by the receiving seat 28 and the cover 30. The spool 32 has a first condition in which it is relatively stationary with respect to the receptacle 28. When the main switch 27 controls the rotation of the motor 26, the spool 32 rotates in synchronization with the housing 28 in the first state.

In this embodiment, the wire coil 32 and the receptacle 28 have two states: in the first state, the wire coil 32 and the accommodating seat 28 rotate synchronously, the grass cutting line 34 wound on the wire coil 32 and the accommodating seat 28 rotate synchronously, and the part of the grass cutting line 34 extending out of the accommodating seat 28 rotates to form a cutting plane for trimming the lawn; in the second state, the wire coil 32 is separated from the accommodating seat 28, the centrifugal force generated by the rotation of the grass mowing line 34 drives the wire coil 32 and the accommodating seat 28 to generate relative motion, so that a rotation speed difference is generated, and further, the centrifugal force of the grass mowing line 34 can pull the grass mowing line to be thrown out of a part to realize line releasing, the grass mowing length is increased, namely, the longer free tail end 34a of the grass mowing line 34 extends out of the accommodating seat 28, so that the grass mowing machine 100 has a larger grass mowing radius.

Referring to fig. 3, when the lawn mower 100 is in operation, the detection module 21 detects a specific parameter reflecting the length of grass mowing, the controller 51 compares the detected specific parameter with a preset parameter, and outputs a comparison result, and the pay-off mechanism is selectively activated according to the comparison result to release the grass mowing line. In this embodiment, the detecting module 21 detects the specific parameter reflecting the grass length in real time, in other embodiments, the detecting module 21 may also intermittently or periodically sample, and the technical spirit of the invention is similar to that of the present invention, and all of them should be covered in the protection scope of the present invention. In this embodiment, the paying-off mechanism is used for selectively releasing the grass mowing line, so that the grass mowing length is increased. The pay-off mechanism comprises at least one pay-off electronic switch and a control device, and the pay-off electronic switch is selectively switched on or switched off according to the comparison result so as to start the control device. Specifically, the control device is selectively activated by the electronic payoff switch to bring the spool 32 into a second state in which a difference in rotational speed between the spool and the receptacle 28 is produced.

In this embodiment, the detection module 21 detects a specific parameter reflecting the workload. Specifically, the detected specific parameter comprises the working current of the grass trimmer. Under the same working condition, particularly the driving voltage is not changed, the larger the load is, the larger the working current is. Specifically, under the condition that the grass trimmer is idle, the longer the grass trimming length is, the larger the working current of the grass trimmer is, and when the grass trimming length is shortened due to abrasion, the working current of the grass trimmer is reduced. That is, the working current of the grass mowing line with the wear set length is calculated to be used as the preset current value, the working current detected in normal working is compared with the preset current value, and if the working current detected in real time is smaller than the preset current value, the fact that the wear of the grass mowing line reaches or exceeds the set length can be judged. Preferably, in the embodiment, the working current of the grass mowing line with the set wear length is measured under the condition that the grass mowing machine is in an idle state and is used as the preset current value. Referring to fig. 18, the working current is detected by the current detection circuit, and then amplified by current sampling and amplification, and the controller MCU receives the working current signal, compares the working current signal with a preset current value, and outputs a comparison result.

Preferably, the grass trimmer 100 is further provided with an adjusting mechanism with preset parameters to compensate for errors in measuring the grass mowing length. In actual work, the detection data deviate due to complex working conditions, specifically, the detection data deviate from the true value due to the difference of the environmental temperature and the temperature rise of the motor, the detection data deviate due to the phenomena of wear and motor aging, and the like, so that the working parameters of the actual wear at the set length are usually different from the preset parameters. In this embodiment, the working current detected when the grass mowing line with the set length is worn is generally not the same as the preset current value, that is, when the working current detected is smaller than the preset current value, the grass mowing line is not just worn by the set length. Therefore, in the grass trimmer 100 of the present embodiment, it is necessary to provide a compensation mechanism capable of adjusting the preset parameters, and the preset parameters can be adjusted or compensated by the adjustment mechanism provided on the grass trimmer, so as to further improve the accuracy of executing the control action according to the detected specific parameters reflecting the grass trimming length, reduce the pay-off error, and maintain the grass trimming length within a preferred range. Specifically, the adjusting structure comprises an external manually-operated knob, when the knob is located at different positions, the controller compares detected specific parameters with adjusted preset parameters, and controls the paying-off mechanism to be started according to the comparison result, and the corresponding compensation values correspond to different compensation values. Therefore, the grass cutting length can be judged more accurately without being influenced by interference factors such as temperature, aging and the like. That is to say, a user adjusts the starting condition of the pay-off mechanism through an external knob, namely the threshold value of the pay-off is triggered, so that the length of the grass mowing line is controlled, when the working condition is severe, the threshold value of the pay-off triggering is properly increased through the adjusting mechanism, the grass mowing length is increased, the cutting radius is increased, and the output power is increased; when the working condition is not severe, the threshold value of the grass mowing line triggering line releasing can be reduced through the adjusting mechanism, the cutting radius is reduced, and the cruising time of a single battery pack is prolonged.

In other implementations, the adjusting structure can judge the degree of abrasion by detecting an ambient temperature signal, a temperature rise signal of a motor and a circuit and according to the running time length of the whole machine, automatically compensate preset parameters and eliminate measurement errors caused by interference factors. The compensation mode adopts a fully automatic mode, so that the paying-off of the grass trimmer is automatically adjusted according to the external or self working conditions, and the grass trimmer is more intelligent.

In this embodiment, the controller 51 is configured to store a preset parameter and compare the preset parameter with the detected specific parameter, so as to output a comparison result. Specifically, the controller prestores a preset current value i of the grass mowing line with the preset abrasion length₀In the working process of the grass trimmer, the detected working current i and the preset current value i are detected₀Making a comparison if i<i₀And outputting a control signal to start the pay-off mechanism.

Preferably, the parameter detected by the detection module 21 further includes a driving voltage, specifically, a voltage output across the battery pack 38 or a voltage across the motor 26. Specifically, the detection module detects the driving voltage in a real-time sampling manner, and in other embodiments, the detection module may also detect the driving voltage periodically, intermittently, or in other detection manners. The lithium battery characteristics determine that the input voltage is not constant, and the voltage gradually decreases with the increase of the discharge time. Therefore, under the same load, when the length of the mowing line is fixed, the working currents required by different driving voltages are different, that is, the preset current values can change along with the different driving voltages, and specifically, the preset current values are in a one-to-one correspondence relationship, that is, one driving voltage only corresponds to one preset current value i₀。

The controller 51 pre-stores the variation relationship between the driving voltage and the working current of the grass mowing line with the set wear length, and firstly, the controller calculates the driving voltage V detected by the detection module to obtain a preset current value i₀Then the detected current i is compared with a preset current value i₀Making a comparison if i<i₀And outputting a control signal to start the pay-off mechanism. Referring to fig. 18, the driving voltage is detected by the voltage detection circuit, and the controller MCU calculates a preset current value by receiving the driving voltage signal, compares the detected working current with the preset current value, and outputs a comparison result.

In other embodiments, the detection module does not detect voltage, and only needs to set a voltage stabilizing module on the output power supply to stabilize the voltages at two ends of the motor or the battery pack at a certain value, calculate a preset current value through the stabilized voltage, compare the working current detected during normal operation with the preset current value, and if the detected current is smaller than the preset current, the controller outputs a control signal to start the paying-off mechanism.

In this embodiment, the paying-off mechanism includes at least one paying-off electronic switch and a control device, and specifically, the paying-off electronic switch selectively activates the control device according to a control signal output by the controller so that the wire coil is in a second state where a rotation speed difference is generated between the wire coil and the accommodating seat. In this embodiment, the control device comprises the motor 26, and in other embodiments, the control device may also comprise other driving devices, such as an electromagnet or a secondary motor independent of the motor 26, as long as the driving device enables the second state of the rotation speed difference between the wire coil and the receiving seat to be generated, and the second state is within the protection scope of the present invention.

In this embodiment, the control device further includes a control circuit electrically connected to the motor 26, and the control circuit is used for controlling the rotation speed variation of the motor 26 during operation. In the present embodiment, the yarn feeding rotation speed V1 is lower than the operating rotation speed V0. The control circuit preferably employs a brake switch circuit E2. The following description refers to the motor M specifically being the motor 26 of the grass trimmer provided in this embodiment, the main switch K1 being the main switch 27 of the grass trimmer provided in this embodiment, and the pay-off electronic switch K2 being the pay-off electronic switch of the grass trimmer provided in this embodiment.

Referring to fig. 4, a power source P supplies power to the motor M, and a main switch K1 is electrically connected to the motor M. The brake switch circuit E2 includes an electronic payoff switch K2, an electronic payoff switch K2 having an NC terminal and an NO terminal, the NC terminal and the NO terminal being selectively in a closed position. When the grass mowing line is worn and shortened in the cutting process, the controller recognizes that the current i detected by the detection module is smaller than a preset current value i₀I.e. i<i₀The controller outputs a control signal to actuate the electronic pay-off switch K2. Specifically, the pay-off electronic switch K2 is disconnected from the NC end and closed from the NO end, a brake switch circuit E2 is started, the rotating speed of the motor is reduced from V0 to V1, and the rotating speed difference is generated between the wire coil and the accommodating seatAnd a second state. Referring to FIG. 5, in normal operation of the lawnmower, the pay-off electronic switch NC is in the closed position, the main switch K1 is closed, and the motor M is running at full speed.

Referring to fig. 6, when the cable is released, the cable releasing electronic switch K2 is disconnected from the NC terminal and is in the closed position with the NO terminal, the motor M is short-circuited, and the rotation speed of the motor M drops to zero.

Referring again to fig. 4, when the payoff process is complete, payoff electronic switch K2 is disconnected from the NO terminal, payoff electronic switch K2 and NC terminal are in the closed position, and motor M resumes full speed operation.

The K2 electronic switch is not limited to the above-described structure, and other electronic component configurations capable of achieving line opening and closing under the control of electronic signals or mechanical control, such as MOS transistor switch circuits, should be covered by the present invention.

Referring to fig. 7, the variation of the operating speed V of the motor M with time T is illustrated. Under normal operating conditions, the motor M of the grass trimmer has an operating speed V0 of 5000 to 10000 rpm, preferably 8500 rpm as the operating speed V0. The pay-off speed V1 is about 0 to 3000 rpm, preferably 0 rpm, i.e. the pay-off speed V1 of the motor M is reduced to 0 to 3000 rpm. In the present embodiment, on the time axis T, where the operation speed of the motor M is reduced from the operating rotation speed V0 to zero in the T1 time period, the T1 time period is less than 1 second; the zero rotating speed is maintained for a time period of t2, and after a set time period of t2, the NO end of the pay-off electronic switch K2 is disconnected and then is closed with the NC end; the running speed of the motor M is restored to the working speed V0 from zero after the NC end of the pay-off electronic switch is closed in a t3 time period, and the t3 time period is also less than 1 second. As can be seen from the above, the whole paying-off process lasts for the sum of the time t1, the time t2 and the time t3, the paying-off process is ended, the paying-off electronic switch K2 is restored to be closed with the NC terminal (as shown in FIG. 4), and the motor M runs at full speed.

In this embodiment, if i<i₀The control signal output by the controller starts the pay-off mechanism to pay off a primary wire, and the controller stops outputting the control signal or the pay-off machine in the pay-off process executed by the pay-off mechanismThe mechanism does not respond to the control signal of the controller during the paying-off process until the paying-off process is finished. If the last paying-off process is finished, the controller detects i again<i₀And starting the pay-off mechanism again to pay off. Therefore, misjudgment caused by unstable current in the paying-off process is avoided, paying-off is only executed once according to the judgment result every time, and waste of a grass mowing line caused by excessive paying-off is avoided.

Specifically, the electronic pay-off switch can activate the control circuit to change the rotation speed of the motor 26 during operation, i.e., between the pay-off rotation speed V1 and the operating rotation speed V0, so as to switch the wire coil 32 and the housing 28 between two states, i.e., between a synchronous rotation state and a relative movement state of the wire coil 32 and the housing 28. The following describes in detail the structure for switching the two states of the wire coil 32 and the housing 28.

Referring to fig. 8 and 9, the accommodating seat 28 is provided with a strip-shaped hole (not shown) extending in the radial direction, and the slider 33 is inserted into the strip-shaped hole and is circumferentially fixed and movably coupled with the accommodating seat 28 in the radial direction. The sliders 33 move radially so that the wire coil 32 can move circumferentially with a difference in rotation speed with respect to the housing seats 28. The wire coil 32 is provided with a tooth-shaped groove 37 extending in the circumferential direction, the tooth-shaped groove 37 comprises a first tooth-shaped edge 39 and a second tooth-shaped edge 41 which are arranged oppositely, the number of teeth on the first tooth-shaped edge 39 and the second tooth-shaped edge 41 is the same, the teeth are arranged in a circumferentially staggered manner, each tooth on the first tooth-shaped edge 39 comprises a radial surface 45 extending in the radial direction and a circumferential surface 47 extending in the circumferential direction in an inclined manner, and each tooth on the second tooth-shaped edge 41 comprises a radial surface 45 extending in the radial direction and a circumferential surface 47 extending in the circumferential direction in an inclined; the slide block 33 is provided with a protruding tooth 49 which can move in the radial direction in the tooth-shaped groove 37, and when the protruding tooth 49 is abutted against the radial surface 45, the slide block 33 drives the wire coil 32 to rotate synchronously with the accommodating seat 28; when the projecting tooth 49 abuts against the circumferential surface 47, the slider 33 drives the spool 32 to move relative to the housing seat 28, thereby generating a speed difference.

Referring to fig. 13, a biasing member 54 is disposed between the receiving seat 28 and the slider 33, and the biasing member 54 applies force to the slider 33 to keep the slider 33 rotating with the wire coil 32 and the receiving seat 28 synchronously. Thus, the slider 33 is only driven to slide against the force of the biasing element 54 to move the wire coil 32 circumferentially and produce a rotational speed difference with the housing seat 28. The biasing member 54 of the present embodiment is a coil spring, and those skilled in the art will appreciate that other biasing members, such as tension springs, may be used to achieve the same effect.

Thus, in this embodiment, the grass-mowing head rotates in the counterclockwise direction R, the spool 32 moves between three positions under the action of centrifugal force, and in the first position, the spool 32 is in the first state; in the second position, the spool 32 is in the second state; in the third position, the spool 32 is again in the first state.

Specifically, as shown in fig. 8, in the first position, the protruding tooth 49 on the slider 33 abuts against the radial surface 45 of the first toothed edge 39, and the slider 33 can drive the wire coil 32 and the receiving seat 28 to rotate synchronously.

As shown in fig. 9, in the second position, the projecting tooth 49 on the slider 33 does not abut against the radial surface 45 of any tooth on any tooth-shaped side, and in the second position, there are two cases: in one case, the protruding tooth 49 abuts against the circumferential surface 47 on the second toothed edge 41, and the linear motion of the slider 33 drives the drum 32 to rotate relative to the housing seat 28; alternatively, the projecting teeth 49 do not abut the circumferential surface 47, the rotation of the spool 32 causes the rotation of the mowing line 34, and the centrifugal force generated by the free end 34a of the mowing line causes the spool 32 to rotate relative to the receptacle 28.

As shown in fig. 10, in the third position, the protruding tooth 49 on the slider 33 abuts against the radial surface 45 on the second toothed edge 41, and the slider 33 can drive the spool 32 and the receiving seat 28 to rotate synchronously.

The biasing member 54 urges the wire coil 32 from the third position to a fourth, fifth position, the wire coil 32 being in the second state in the fourth position, and the wire coil 32 being in the first state in the fifth position.

Specifically, as shown in fig. 11, in the fourth position, the protruding tooth 49 on the slider 33 does not abut against the radial surface 45 of any tooth on any tooth-shaped side, and the fourth position has two cases: in the first case, the protruding tooth 49 abuts against the circumferential surface 47 of the first toothed edge 39, and the slider 33 drives the spool 32 to rotate relative to the housing seat 28, in the second case, the protruding tooth 49 does not abut against the circumferential surface 47, the spool 32 rotates to drive the mowing line to rotate, and the centrifugal force generated by the free end 34a of the mowing line also drives the spool 32 to rotate relative to the housing seat 28.

As shown in fig. 12, in the fifth position, the protruding tooth 49 of the slider 33 abuts against the radial surface 45 of the first toothed edge 39, and the slider 33 rotates the spool 32 and the housing 28 in synchronization.

In this embodiment, the two protruding teeth 49 are provided, and the two protruding teeth 49 are spaced apart from each other in the extending direction of the slider 33 by a distance that is the diameter of the central circle of the tooth-shaped groove 37, so that when the first protruding tooth 49 is engaged with the first tooth-shaped edge 39, the radial other end of the second protruding tooth 49 is engaged with the second tooth-shaped edge 41, and the force applied to the wire coil 232 can be more uniform. It will be appreciated by those skilled in the art that only one projecting tooth may be provided.

In this embodiment, the electronic paying-off switch can automatically control the control circuit according to the control signal of the control mechanism to enable the motor to change between the paying-off rotating speed V1 and the working rotating speed V0, and the wire coil 32 moves between three positions under the action of centrifugal force, that is, the wire coil 32 and the accommodating seat 28 are switched between a synchronous rotating state and a relative moving state, so as to realize automatic paying-off. The controller controls the action of the paying-off electronic switch according to the specific parameters detected by the detection module, and the paying-off is performed once in each action, so that the automatic paying-off can be realized, and the paying-off is reliable.

Referring to fig. 13, the pay-off mechanism further includes a stopping device 401 movably disposed on the receiving seat 28, the stopping device 401 has a first position and a second position, wherein during the conversion process between the first position and the second position, the sliding block 33 radially moves relative to the receiving seat 28, so that the wire coil 32 and the receiving seat 28 relatively move. So that a relative speed difference is generated between the wire coil 32 and the receiving seat 28, and the wire is paid out.

Further, when the stopping device 401 is in the first position, the stopping device 401 limits the radial movement of the slider 33 relative to the receiving seat 28, so that the wire coil 32 and the receiving seat 28 are kept relatively still, and the wire can not be paid out. When the stopping device 401 is in the second position, the slider 33 is radially movable with respect to the housing seat 28. The radial movement of the slider 33 with respect to the housing 28 pushes the spool 32 to rotate at a certain angle with respect to the housing 28, and a relative speed difference is generated between the spool 32 and the housing 28, thereby unwinding the spool.

The stopping device 401 includes a stopper 403 pivotally disposed on the receiving seat 28, and when the stopper 403 is at the first position, the stopper 403 stops the slider 33 to limit the radial movement of the slider 33 relative to the receiving seat 28, so that the wire coil 32 is stationary relative to the receiving seat 28 and cannot be paid off. When the stop member 403 pivots to the second position, the sliding block 33 can move radially relative to the receiving seat 28, so as to push the wire coil 32 to rotate a certain angle relative to the receiving seat 28, thereby realizing wire unwinding.

Preferably, the pivot axis of the stopper 403 overlaps with the axis of rotation of the housing seat 28. Therefore, the pay-off mechanism is compact in structure, and the volume of the grass mower 400 is small. Of course, the pivot axis of the stop member 403 and the axis of rotation of the housing seat 28 may be arranged so as not to overlap, and preferably, may be arranged parallel to each other.

The stopping device 401 further comprises a resetting device 405 arranged between the stopping member 403 and the receiving seat 28, wherein the resetting device 405 urges the stopping member 403 to return from the second position to the first position. In this embodiment, the reset means 405 is provided as a compression spring 405. Of course, the reset device 405 may be provided with other elastic devices such as a tension spring, a torsion spring, etc.

As shown in fig. 13 and 14, in particular, the stopper 403 has a stopper protrusion 407 and a mounting portion 409, the slider 33 has a first end 411 capable of extending out of the outer periphery of the receiving seat 28 and a second end 413 opposite to the first end 411, and the second end 413 is located inside the outer periphery of the receiving seat 28. The biasing member 54 is disposed between the receptacle 28 and the second end 413. The slider 33 further includes a hollow portion 415 and an abutting portion 417, the hollow portion 415 is located between the first end portion 411 and the second end portion 413, and the abutting portion 417 extends from the second end portion 413 toward the rotation center of the housing seat 28.

One end of the compression spring 405 is inserted into the mounting portion 409, the other end of the compression spring 405 abuts against the housing seat 28, and the direction of the acting force of the compression spring 405 on the stopper 407 is opposite to the rotation direction of the housing seat.

When the stopper 403 is in the first position under the force of the compression spring 405, the stopper protrusion 407 abuts against the abutting portion 417 of the slider 33. When the stop member 403 pivots from the first position to the second position, the stop protrusion 407 is disengaged from the abutting portion 417 of the slider 33 against the action of the compression spring 405, so that the slider 33 radially moves relative to the accommodating seat 28 under the action of the biasing member 54, the slider 33 moves in a direction extending out of the accommodating seat 28, and the wire coil 32 (see fig. 13) is pushed to rotate by a certain angle relative to the accommodating seat 28, so as to realize wire unwinding.

As shown in fig. 14, when the lawnmower 400 is in the non-operating state, the stopper 403 is in the first position for restricting the radial movement of the slider 33 with respect to the housing 28 by the urging force of the compression spring 405. And at this time, the abutting portion 417 of the slider 33 is held in abutment with the stopper projection 407 of the stopper 403 by the urging force of the biasing member 54.

As shown in fig. 15, the main switch 27 is activated, and the stop member 403 is still in the first position for limiting the radial movement of the slider 33 relative to the housing 28 under the action of the compressed spring 405. When the slider 33 rotates with the receiving seat 28, a centrifugal force is generated on the slider 33, and the direction of the centrifugal force is opposite to the direction of the biasing member 54. Therefore, the slider 33 is separated from the rotation axis of the housing seat 28 by a certain gap from the stopper 403 against the biasing force of the biasing member 54 by the centrifugal force. However, the stopper 403 restricts the radial movement of the slider 33 relative to the housing seat 28 in a direction extending beyond the outer peripheral portion of the housing seat 28. The spool 32 (see fig. 13) and the receptacle 28 remain relatively stationary and the lawnmower 400 cannot pay out the line. Thereby avoiding the loss of the grass cutting line.

Referring to fig. 16, when the electronic pay-off switch (not shown) of the pay-off mechanism is activated according to the output signal of the controller, the rotation speed of the housing seat 28 is rapidly reduced, so that the housing seat 28 has a certain acceleration in a direction opposite to the rotation direction of the housing seat 28, and at this time, the stopper 403 tends to keep the original motion state due to the inertia of the stopper 403, that is, the stopper 403 has a certain inertia force and rotates in a direction opposite to the acceleration due to the inertia force. Specifically, the rotational speed of the housing 28 is rapidly reduced, and the inertial force of the stopper 403 is greater than the force of the compression spring 405, so that the stopper 403 pivots from the first position to the second position relative to the housing 28 against the force of the compression spring 405 by the inertial force. At this time, the stop protrusion 407 of the stop member 403 is disengaged from the abutment portion 417 of the slider 33, and since the rotation speed of the receiving seat 28 is greatly reduced and the centrifugal force of the slider 33 is smaller than the acting force of the biasing member 54, the slider 33 is moved radially relative to the receiving seat 28 against the centrifugal force by the biasing member 54, and the slider 33 is moved in a direction extending out of the receiving seat 28, so as to push the wire coil 32 (see fig. 13) to rotate a certain angle relative to the receiving seat 28, thereby realizing the wire unwinding. So, paying out machine constructs can carry out the unwrapping wire according to needs selective start unwrapping wire electronic switch automatically, has avoided the waste of beating the grass line.

Referring to fig. 17, the operation of the pay-off mechanism during the operation of the lawn mower 100 of the present embodiment will be described. The main switch 27 is started to lead the wire coil 32 and the containing seat 28 to synchronously rotate; the detection module detects voltage and current; the controller calculates a preset current value i according to the detected voltage₀If i is<i₀And judging that the paying-off condition is met, actuating a paying-off electronic switch K2, and starting a paying-off mechanism to pay off. In particular, if i<i₀When the wire releasing electronic switch K2 is closed with the NO terminal (see fig. 6), the rotation speed of the motor is reduced from V0 to V1, the slider 33 is moved radially relative to the housing seat 28 against the centrifugal force by the biasing member 54, and the slider 33 is moved in the direction extending out of the housing seat 28, so as to push the wire coil 32 (see fig. 13) to rotate a certain angle relative to the housing seat 28, thereby releasing the wire.

In this embodiment, the electronic paying-off switch in the brake switch circuit is implemented by MOS switches Q1 and Q2. When the controller judges that the paying-off condition is met, the controller MCU outputs a control signal to disconnect the Q1 and close the Q2, the motor is in short circuit, and the paying-off mechanism starts to execute the braking paying-off.

Referring to fig. 18, the controller of the grass trimmer in this embodiment adopts an MCU, and the detection modules are specifically a current detection circuit and a voltage detection circuit shown in the figure. The controller samples the current and the voltage, and calculates a preset current value i through the sampled voltage₀Comparing the sampled current i with a preset current value i₀Performing comparison calculation, if the paying-off condition is met, i<i₀And the controller MCU outputs a control signal to open the Q1 and close the Q2 so as to start the pay-off mechanism to execute the brake pay-off. Specifically, the main switch K1 is closed, the motor is powered on, the grass trimmer runs, meanwhile, Q1 is in a closed state, and Q2 is in an open state; when the controller judges that the paying-off condition is met, the controller outputs a control signal to open the Q1 and close the Q2, the motor is in short circuit, and the grass trimmer executes the braking paying-off. Wherein, Q1 is driven by the operation MOS drive circuit, and Q2 is driven by the brake MOS drive circuit.

Referring to fig. 5, the main switch K1 is closed, the electronic pay-off switch K2 is connected to the NC terminal, i.e., the main switch is closed, Q1 is in a closed state, Q2 is in an open state, and the lawnmower is operated at full speed; when the controller determines that the line releasing condition is satisfied, referring to fig. 6, the line releasing electronic switch K2 is disconnected from the NC terminal and connected to the NO terminal, that is, the main switch in fig. 18 is closed, Q1 is in an open state, Q2 is in a closed state, the motor M is short-circuited, and the lawn mower brakes and releases the line. From the above, the paying-off electronic switch K2 is specifically a MOS transistor switch Q1 and Q2, and the controller switches the lawn mower between normal operation and braking paying-off by controlling the on and off of Q1 and Q2.

Because this paying out machine constructs through setting up the controller control alone, the controller is according to the parameter automatic output control result that detection module detected to selectivity control unwrapping wire electronic switch K2's action, thereby selectivity start paying out machine constructs, need not artificial operation, makes the quick-witted unwrapping wire of beating grass more intelligent.

FIG. 19 is a schematic view of the operation of a lawnmower according to a second embodiment of the present invention.

The grass trimmer shown in the present embodiment has a similar structure to the grass trimmer 100 of the first embodiment, and the differences will be described in detail below, and for convenience of description, the same structures are denoted by the same reference numerals and are not repeated.

Referring to fig. 19, the detecting module is used for detecting specific parameters reflecting the grass mowing length, and specifically, the detected specific parameters include a motor rotating speed S reflecting a working load. Under the same working conditions of the grass trimmer, in the embodiment, under the condition that the grass trimmer is in no load, the longer the grass trimming length is, the smaller the rotating speed of the motor is. That is, in the idle condition, the rotation speed of the motor is calculated as the preset rotation speed value S when the grass mowing line with the set wear length is worn₀Comparing the detected motor speed S during normal operation with a preset motor speed value S₀Comparing, if the detected motor speed is greater than the preset motor speed value, S>S₀And then, judging that the grass mowing line is worn by a set length, and outputting a control signal by the controller to start the paying-off mechanism.

In this embodiment, the parameter detected by the detection module further includes a driving voltage V, specifically, a voltage output from two ends of the battery pack 38 or a voltage output from two ends of the motor 26. Under the same load, when the length of the mowing line is fixed, the rotating speeds of the motors corresponding to different driving voltages are different, namely the rotating speeds of the motors can change along with the different driving voltages, and specifically form a one-to-one correspondence relationship, namely, one driving voltage only corresponds to one preset rotating speed value S₀. The controller is stored with the variation relation between the driving voltage V and the motor rotating speed S of the grass mowing line with the set abrasion length in advance, and the controller firstly calculates the preset motor rotating speed value S through the voltage V detected by the detection module₀Then the detected motor rotation speed S and a preset rotation speed value S are compared₀Making a comparison if S>S₀And the controller outputs a control signal to start the pay-off mechanism. In other embodiments, the detection module does not detect the voltage, and only needs to provide a voltage stabilizing module on the output power source to enable the two ends of the motor or the battery pack to be connectedThe voltage is stabilized on a determined value, the preset rotating speed value is calculated through the stabilized voltage, the rotating speed of the motor detected in normal work is compared with the preset rotating speed value, if the rotating speed of the motor detected in real time is smaller than the preset rotating speed value, the grass mowing line is judged to be worn out by a set length, and the controller outputs a control signal to start the paying-off mechanism.

Fig. 20 and 23 show a lawnmower 200 according to a third embodiment of the present invention.

The grass trimmer 200 shown in the present embodiment has a similar structure to the grass trimmer 100 of the first embodiment, and the differences will be described in detail below, and for convenience of description, the same structures are denoted by the same reference numerals and will not be described again.

In this embodiment, the specific parameter detected by the detection module is a parameter reflecting the actual physical length of the grass mowing length. Specifically, the specific parameter detected by the detection module is a photoelectric signal of the photoelectric element. More specifically, the optoelectronic elements comprise at least an optoelectronic element emitting an optoelectronic signal and an optoelectronic element receiving an optoelectronic signal, the reception of said optoelectronic element being able to be influenced by the grass-cutting line. In particular, the grass cord can block the photoelectric signal from reaching the photoelectric element for receiving light, or the grass cord can reflect the originally unreceived photoelectric signal to the photoelectric element for receiving light.

Referring to fig. 20 and 21, the cutting radius of the grass trimmer 200 of the present embodiment is r, the cutting radius r defines a cutting area, the detecting module includes at least a pair of spaced optoelectronic devices 101, one of the optoelectronic devices is used for emitting an optoelectronic signal, the other is used for receiving an optoelectronic signal, and the free end 34a of the grass trimming line 34 can block the receiving of the optoelectronic signal. Specifically, the photoelectric element is arranged at intervals, so that the tail end of the grass mowing line passes through the intervals when the grass mowing machine works, when the grass mowing line passes through the intervals, the photoelectric element for receiving the photoelectric signal cannot receive the photoelectric signal, the photoelectric signal detected by the photoelectric element displays that the grass mowing length is normal, when the grass mowing line is abraded to reach or exceed the set length, the grass mowing line is shortened to be incapable of passing through the intervals, the signal of the photoelectric element changes, the controller compares the changed photoelectric signal with the preset parameter, identifies the changed abnormal photoelectric signal, and outputs a control signal to start the pay-off mechanism to release the grass mowing line. More specifically, the preset parameters comprise a preset photoelectric signal when the grass mowing length is abraded to reach or exceed a set length, the photoelectric signal is compared with the preset photoelectric signal, and if the photoelectric signal is different from the preset photoelectric signal, the paying-off mechanism is started to release the grass mowing line; the preset parameters comprise preset photoelectric signals when the grass mowing length is abraded to reach or exceed a set length, the photoelectric signals are compared with the preset photoelectric signals, and if the photoelectric signals are the same as the preset photoelectric signals, the paying-off mechanism is started to release the grass mowing line.

In this embodiment, the photoelectric elements are oppositely arranged on the housing at intervals, and the interval d is used for the free tail end 34a of the grass mowing line 34 to pass through when the grass mowing machine works. In particular, the photoelectric element 101 is arranged in the vicinity of the path traversed by the free end 34a when the length of grass mowing is at its maximum during normal operation of the grass trimmer, said photoelectric element being arranged parallel to the axis L, in other embodiments, the photoelectric element may also be arranged at an oblique angle, provided that its spacing is such as to provide a gap traversed by the free end 34a during operation of the grass trimmer and to affect the reception of the photoelectric signal, all within the scope of the present invention. When the terminal wearing and tearing back of line of beating grass, free end 34a shortens can't pass through interval between the photoelectric element, also can't be right photoelectric element's signal reception produces the influence, and the signal that photoelectric element detected changes, and the signal of this change is unusual signal, instructs the length of beating grass to shorten, and the controller basis unusual signal compares with the parameter of predetermineeing, discerns the length of beating grass and has worn out the settlement length, and output control signal carries out the unwrapping wire with start paying out machine structure.

In other embodiments, the photovoltaic elements may be angularly spaced. Specifically, the optoelectronic elements are not on the same line, the signal emitted by the optoelectronic element responsible for emitting the signal cannot be directly received by the optoelectronic element responsible for receiving the signal, and only the object existing in the space reflects the emitted signal to the optoelectronic element responsible for receiving the signal. In the embodiment, the unworn grass mowing length can reflect the signal of the photoelectric element responsible for transmitting the signal to the photoelectric element receiving the signal through the interval between the photoelectric elements, so that the grass mowing length is judged to be in a normal state, and the signal detected by the photoelectric element in the normal state is a normal signal; when the grass mowing line is worn, the length of the grass mowing line is not long enough to reflect the photoelectric signal of the photoelectric element for emitting the signal, so that the photoelectric element for receiving the signal has no signal reception, the signal of the photoelectric element is an abnormal signal when no signal is received, the controller compares the normal signal with a preset parameter, identifies that the signal is the abnormal signal, judges that the grass mowing line is worn to reach or exceed the set length, and outputs a control signal to start the pay-off mechanism.

Preferably, the photocell 101 has a center of rotation, and the photocell 101 has a distance from the center of rotation that is greater than zero. The photocell can be rotated about the center of rotation to vary the distance from the axis L.

Referring to fig. 22 and 23, when the photoelectric element 101 is located on the distance connecting line between the rotation center of the photoelectric element and the rotation axis of the grass cutting head (see fig. 22), the cutting radius r of the grass cutting machine is the shortest; when the photoelectric element rotates around the rotation center by an angle (refer to fig. 23), the angle is larger than zero, and the cutting radius r of the grass trimmer is lengthened; when the photocell is rotated 180 degrees from the position shown in fig. 22, the cutting radius r of the lawnmower is the longest. The cutting radius of the grass trimmer is changed along with the rotation angle, so that the grass trimming length can be adjusted within a set range by adjusting the rotation angle of the photoelectric element, and the cutting area of the grass trimmer is changed. Specifically, the distance between the photoelectric element 101 and the rotation center thereof determines the size of the setting range. Therefore, the cutting area of the grass trimmer can be changed through the rotation of the photoelectric element, so that the grass trimmer is more flexible to apply.

Fig. 24 and 25 show a lawnmower 300 according to a fourth embodiment of the present invention.

The grass trimmer 300 of the present embodiment has a similar structure to the grass trimmer 200 of the third embodiment, and the differences will be described in detail below, and for convenience of description, the same structures are denoted by the same reference numerals and will not be described again.

The detection module of the lawnmower 300 shown in this embodiment includes an air pressure sensor located near the free end 34 a. The detection module directly detects the air pressure reflecting the actual physical length of the grass mowing length, when the grass mowing line is worn and shortened, the free tail end 34a of the grass mowing line is far away from the air pressure sensor, the air flow near the air pressure sensor is slowed down due to the fact that the free tail end 34a of the rotating grass mowing line is shortened, and the air pressure value detected by the air pressure sensor rises. The grass mowing length is inversely related to the air pressure value measured by the air pressure sensor, namely the shorter the grass mowing length is, the higher the air pressure detected by the air pressure sensor is. Thus, the controller stores the preset air pressure value P of the grass mowing line with the set wear length in advance₀When the grass mowing line is abraded to reach or exceed the set length, the controller enables the air pressure P detected by the air pressure sensor to be equal to the preset air pressure value P₀If P is>P₀Judging that the air pressure signal is abnormal, and when the grass mowing line is abraded to reach or exceed a set length, the controller outputs a control signal to start the pay-off mechanism; if P<P₀And judging that the air pressure signal is normal and the grass mowing length is normal, and outputting a control signal to stop the paying-off mechanism by the controller without paying off.

Fig. 26 and 27 show a lawnmower 400 according to a fifth embodiment of the invention.

The grass trimmer 400 shown in the present embodiment has a similar structure to the grass trimmer 100 of the first embodiment, and the differences will be described in detail below, and for convenience of description, the same structures are denoted by the same reference numerals and will not be described again.

The grass trimmer 400 provided by the embodiment further comprises a line breaking blade 31 arranged on the shell 25, and when the grass trimming line is too long, the line breaking blade 31 is used for cutting off the overlong grass trimming line 34, so that the grass trimming length of the grass trimming line is maintained in a safe and reasonable range. Specifically, the maximum value of the grass cutting length is the target length, when the grass cutting length is the target length, the free tail end of the grass cutting line just touches the line breaking blade 31 on the shell, and the line breaking blade 31 maintains the grass cutting length within the target length.

In this embodiment, the paying-off mechanism is selectively started according to the specific parameter detected by the detection module, specifically, the paying-off mechanism has a starting condition and a terminating condition, if the starting condition is met, the paying-off mechanism is continuously started, and the paying-off mechanism stops paying off until the terminating condition is detected to be met. Specifically, the continuous start of the pay-off mechanism means that the pay-off mechanism is started again to pay off if the termination condition is not met. The specific starting condition of the pay-off mechanism is specifically the condition that needs to be met when the pay-off mechanism is started in all the embodiments, and the starting condition adopted in this embodiment is that the detected current i is smaller than the preset current value i in the first embodiment₀The paying-off mechanism is started to pay off, and the starting conditions described in other embodiments can be adopted. The embodiment the unwrapping wire mode make at every turn the unwrapping wire can both make the length of beating the grass reach target length, make the use of machine of beating the grass nimble more intelligent. The termination condition of the pay-off mechanism adopted by the lawnmower 400 in this embodiment is described in detail below.

Referring to fig. 26 and 27, the lawn mower 400 of the present embodiment further includes a vibration sensor 102, and preferably, the vibration sensor 102 is disposed at the thread cutting blade 31. When the grass cutting length exceeds the target length, the free tail end 34a of the grass cutting line 34 touches the line breaking blade 31 to be cut off, the vibration sensor 102 senses the vibration when the free tail end 34a of the grass cutting line is cut off, the vibration signal serves as a target signal, the controller compares and recognizes the target signal, the termination condition is judged to be met, and a control signal is output to stop the pay-off mechanism to stop the pay-off. In other embodiments, the vibration sensor may be disposed at the housing, and it is within the scope of the present invention to provide the vibration sensor 102 to sense the vibration.

Specifically, controlThe controller is used for calculating a preset current value i through the driving voltage V detected by the detection module to obtain₀Then the detected working current i is compared with a preset current value i₀Making a comparison if i<i₀If the controller identifies the target signal, the controller outputs the control signal to stop the pay-off mechanism and pay off is stopped. According to the paying-off mode, the signal is detected to meet the starting condition every time, the paying-off mechanism can be continuously started before the target signal is not detected, the paying-off mechanism stops paying off until the termination condition is detected, the longest grass-mowing length can be achieved by paying off every time, and the situation that the paying-off mechanism is not started due to the fact that the line is short and caused by detection errors is avoided

FIG. 28 shows a lawnmower according to a sixth embodiment of the present invention.

The grass trimmer shown in this embodiment has a similar structure to the grass trimmer 400 provided in the fifth embodiment, and the differences will be described in detail below, and for convenience of description, the same structures are denoted by the same reference numerals and will not be described again.

In this embodiment, the termination condition comprises a pulse signal of the operating current of the lawnmower. When the grass cutting machine normally grass, when the grass cutting length exceeds the target length and the free tail end of the grass cutting line collides with the short line blade to be cut off, the working current flowing through the motor is suddenly changed, specifically, the working current generates a pulse signal, the intensity of the pulse signal is far higher than an interference signal accompanied in normal operation, and the pulse signal is used as a termination condition of the pay-off mechanism. Specifically, the controller compares the pulse signals detected by the detection module, recognizes that the pulse signals judge that the termination condition is met, and outputs a control signal to stop the pay-off mechanism.

Because the grass trimmer is in the trimming state, the free tail end of the grass trimming line collides with the ground, and the current is unstable, the re-trimming state does not adopt the line releasing mode described in the embodiment. Specifically, the grass trimmer is provided with a mechanism for identifying grass trimming and edge trimming states, when the grass trimmer identifies that the grass trimmer is in the grass trimming state, after the pay-off mechanism is started, the detection module detects a pulse signal of current, the controller judges that the grass trimming length exceeds a target length, and outputs a control signal to stop the pay-off mechanism and stop paying off; when the grass trimmer is in the trimming state, the grass trimmer is switched to the paying-off mode in the first embodiment of the specification due to severe collision of the grass trimming line with the ground, namely the paying-off mechanism is started only once when the controller outputs a control signal every time, namely only one paying-off process is executed, and when the condition that the starting condition is met is detected again, the paying-off mechanism is started again, so that the influence of unstable current caused by collision of the grass trimming line with the ground on the paying-off mechanism is avoided. Specifically, the switch is arranged at the grass mowing and trimming state switching mechanism of the grass mower, when the grass mower is switched to the trimming state, the switch is turned off or disconnected, the detection module detects the turning-off or disconnection state of the switch and recognizes that the grass mower is in the trimming state, and therefore the pay-off mechanism is switched to the pay-off mode in the first embodiment, namely, a line is paid off once when the starting condition is met.

The embodiment the unwrapping wire mode make the target length that can both accurately put at every unwrapping wire, avoided because of the unwrapping wire that error such as detection leads to can not put the condition in place, make the cutting radius of beating the grass machine after triggering the unwrapping wire at every turn be in the biggest cutting radius state all the time, improved the efficiency of beating the grass machine.

Fig. 29 and 30 show a lawnmower 500 according to a seventh embodiment of the present invention.

The grass trimmer shown in the present embodiment has a similar structure to the grass trimmer 300 provided in the fourth embodiment, and the differences will be specifically described below, and for convenience of description, the same structures are denoted by the same reference numerals and are not repeated.

Referring to fig. 29 and 30, the grass trimmer provided in the present embodiment further includes a hall sensor 105 and a magnetic grass trimming line, and specifically, the grass trimming line is doped with a magnetic material. When the line drawing machine normally works, when the free tail end 34a of the line drawing machine passes through the Hall sensor 105, the Hall sensor 105 senses a magnetic signal of the free tail end 34a of the line drawing machine, the line drawing machine is not abraded, a specific parameter detected by the Hall sensor is a normal signal, the controller identifies the normal signal of the Hall sensor, and the controller controls the line drawing mechanism to be in a stop state; when the grass mowing line is worn, the free tail end 34a cannot pass through the induction range of the Hall sensor, the Hall sensor 105 cannot sense a normal magnetic signal, the grass mowing line is worn, and the controller starts the paying-off mechanism to pay off the grass mowing line according to the abnormal signal.

Fig. 31 and 32 show a lawnmower 600 according to an eighth embodiment of the present invention.

Referring to fig. 31 and 32, the lawn mower provided in this embodiment further includes a color recognition sensor disposed on the housing, and a grass line having a certain color, specifically, the color recognition sensor can recognize red, and the grass line is set to red, which is obviously different from green of the lawn, so as to reduce the background interference and improve the accuracy of sensor recognition. When the line drawing machine normally works, when the free tail end of the line drawing machine passes through the color recognition sensor, the color recognition sensor quickly captures a red color signal of the line drawing machine, the line drawing machine is indicated to be not worn, a specific parameter detected by the color recognition sensor is a normal signal, the controller recognizes the normal signal, and the controller controls the line drawing mechanism to be in a stop state; when the grass mowing line is worn, the free tail end cannot pass through the sensing range of the color recognition sensor, the color recognition sensor cannot capture abnormal signals of specific parameters detected by normal color signals, the grass mowing line is worn, and the controller starts the pay-off mechanism to pay off according to the abnormal signals.

FIG. 33 shows that the invention also provides a line-releasing method of the grass trimmer.

The line releasing method of the grass trimmer provided by the invention is based on the grass trimmer provided by any embodiment, and comprises the following steps:

s1: specific parameters reflecting the length of the grass are detected.

The detection module of the grass trimmer is used for detecting specific parameters reflecting the grass trimming length. In particular, the specific parameters detected by the grass trimmer as described in any of the above embodiments. In the normal working process of the grass trimmer, the detection module detects specific parameters reflecting the grass trimming length, and the specific parameters are parameters reflecting the working load or parameters reflecting the actual grass trimming length.

S2: and comparing the specific parameter with a preset parameter, and outputting a judgment result.

The controller of the grass trimmer compares the detected specific parameter reflecting the grass trimming length with a preset parameter. Specifically, the preset parameter is a parameter pre-stored in the controller, and may be a fixed value or a parameter that varies with the operating condition. Specifically, the working conditions include the driving voltage and other working conditions, the parameters detected by the detection module further include the driving voltage or other parameters reflecting other working conditions, and the corresponding preset parameters are calculated according to the driving voltage or the parameters of other working conditions. According to the paying-off method of the grass trimmer, the controller compares the detected specific parameter reflecting the grass trimming length with the preset parameter and outputs a judgment result.

If the specific parameter detected in step S2 is the working current i, the parameter detected by the detection module further includes the driving voltage, and the controller calculates the current preset current value i according to the driving voltage₀. Will detectWorking current i and preset current value i₀Making a comparison if i<i₀And outputting a control signal to start the pay-off mechanism.

If the specific parameter detected in step S2 is the motor rotation speed S, the parameter detected by the detection module further includes a driving voltage, and the controller calculates the current preset rotation speed value S according to the driving voltage₀. The detected motor rotation speed S and a preset rotation speed value S₀Making a comparison if S>S₀And outputting a control signal to start the pay-off mechanism.

The detection module can not detect voltage, only a voltage stabilizing module is arranged on the output power supply, so that the voltages at two ends of the motor or the battery pack are stabilized on a determined value, a preset rotating speed value is calculated through the stable voltage, the working current detected in normal working is compared with a preset current value, and if the detected current is smaller than the preset current, the controller outputs a control signal to start the pay-off mechanism.

If the specific parameter detected in step S2 is a photoelectric signal, the detection module transmits the detected photoelectric signal to the controller, and the controller determines whether the photoelectric signal is normal. Specifically, free end 34a shortens and can't pass interval between the photoelectric element, and the signal that photoelectric element detected changes, and the signal of this change is unusual signal, will unusual signal sends the controller, and the controller judges that grass length wearing and tearing are beaten, output control signal in order to start paying out machine structure.

If the specific parameter detected in step S2 is an air pressure signal, the detection module transmits the detected air pressure signal to the controller, and the controller determines whether the air pressure signal is normal. Specifically, the controller is pre-stored with a preset air pressure value P of a grass mowing line with a preset abrasion length₀When the grass mowing line is abraded to reach or exceed the set length, the controller enables the air pressure P detected by the air pressure sensor to be equal to the preset air pressure value P₀If P is>P₀And judging that the air pressure signal is abnormal, and when the abrasion of the grass mowing line reaches or exceeds the set length, the controller outputs a control signal to start the paying-off mechanism.

If the specific parameter detected in step S2 is a parameter reflecting the actual physical length of the grass length. The photoelectric element comprises at least one pair of photoelectric elements arranged at intervals. Specifically, the specific parameter detected by the detection module is a photoelectric signal of the photoelectric element. More specifically, the optoelectronic elements comprise at least an optoelectronic element emitting an optoelectronic signal and an optoelectronic element receiving an optoelectronic signal, the reception of said optoelectronic element being able to be influenced by the grass-cutting line. In particular, the grass cord can block the photoelectric signal from reaching the photoelectric element for receiving light, or the grass cord can reflect the originally unreceived photoelectric signal to the photoelectric element for receiving light. When the grass cutting line cannot influence the signal reception of the light spot element, namely the tail end of the grass cutting line does not penetrate through the interval any more, the signal detected by the photoelectric element is an abnormal signal, and the controller selectively outputs a control result according to the signal of the photoelectric element so as to start the pay-off mechanism. More specifically, the preset parameters comprise a preset photoelectric signal when the grass mowing length is abraded to reach or exceed a set length, the photoelectric signal is compared with the preset photoelectric signal, and if the photoelectric signal is different from the preset photoelectric signal, the paying-off mechanism is started to release the grass mowing line; the preset parameters comprise preset photoelectric signals when the grass mowing length is abraded to reach or exceed a set length, the photoelectric signals are compared with the preset photoelectric signals, and if the photoelectric signals are the same as the preset photoelectric signals, the paying-off mechanism is started to release the grass mowing line.

Referring to fig. 33, in the paying-off method of the grass trimmer according to the present invention, the detection module detects and reflects a specific parameter of the grass trimming length, and outputs the specific parameter to the controller, and the controller compares the specific parameter with a preset parameter value and outputs a comparison result to selectively start the paying-off mechanism to pay off the grass. The paying-off method provided by the invention does not need manual operation, is more intelligent and is reliable in paying-off.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

It will be appreciated by those skilled in the art that the invention can be implemented in other ways, provided that the technical spirit of the invention is the same as or similar to the invention, or that any changes and substitutions based on the invention are within the protection scope of the invention.

Claims

1. A lawnmower comprising:

an extension rod;

the shell is arranged at one end of the extension rod;

the grass cutting head is connected to the shell and is provided with a wire outlet;

a motor for driving the grass cutting head to rotate around an axis;

the grass mowing line extends out of the line outlet, and the extending length is the grass mowing length;

the paying-off mechanism can selectively release the grass mowing line and increase the grass mowing length;

the detection module detects a specific parameter reflecting the grass mowing length when the grass mowing machine performs cutting work;

the controller is used for comparing the specific parameter with a preset parameter and further outputting a comparison result;

the method is characterized in that: and the paying-off mechanism is selectively started according to the comparison result so as to release the grass mowing line.

2. A lawnmower according to claim 1, wherein: the specific parameter is a parameter reflecting a workload.

3. A lawnmower according to claim 2, wherein: the specific parameters comprise the working current of the grass trimmer, and the preset parameters comprise preset current values.

4. A lawnmower according to claim 3, wherein: the controller compares the working current with the preset current value, and if the working current is smaller than the preset current value, the controller outputs a control signal to start the pay-off mechanism to release the grass mowing line.

5. A lawnmower according to claim 4, wherein: the parameters detected by the detection module further comprise voltage, and the controller calculates the preset current value through the voltage.

6. A lawnmower according to claim 2, wherein: the specific parameter comprises the rotational speed of the motor,

the preset parameter comprises a preset motor rotating speed value.

7. A lawnmower according to claim 6, wherein: the controller compares the rotating speed detected by the detection module with the preset motor rotating speed value, and if the detected rotating speed is greater than the preset motor rotating speed value, the controller outputs a control signal to start the paying-off mechanism to release the grass mowing line.

8. A lawnmower according to claim 7, wherein: the parameters detected by the detection module further comprise voltage, and the controller calculates the preset motor rotating speed value through the voltage.

9. A lawnmower according to claim 1, wherein: the specific parameter is a parameter reflecting the actual physical length of the grass mowing length.

10. A lawnmower according to claim 9, wherein: the specific parameters comprise air pressure near the tail end of the grass mowing length, and the detection module comprises an air pressure parameter detection module for detecting air pressure changes caused by different grass mowing lengths.

11. A lawnmower according to claim 10, wherein: the controller compares the air pressure value detected by the detection module with a preset air pressure value, and if the detected air pressure value is greater than the preset air pressure value, the controller outputs a control signal to start the pay-off mechanism to release the grass mowing line.

12. A lawnmower according to claim 9, wherein: the detection module comprises at least one pair of photoelectric elements, one of the photoelectric elements is used for emitting an optical electric signal, the other photoelectric element is used for receiving an optical electric signal, and the grass cutting line can influence the receiving of the photoelectric signal.

13. A lawnmower according to claim 12, wherein: the photoelectric elements are arranged at intervals, the interval is used for the tail end of the grass mowing length to pass through when the grass mowing machine works, when the tail end passes through the interval, the photoelectric signal is cut off, the photoelectric element used for receiving the photoelectric signal does not receive the photoelectric signal any more, and the controller outputs a control signal to start the paying-off mechanism according to the signal of the photoelectric element.

14. A lawnmower according to claim 12, wherein: the photoelectric elements are arranged at intervals, the tail end of the grass mowing length passes through the intervals when the grass mowing machine works, when the tail end passes through the intervals, the photoelectric signals are reflected, the photoelectric elements used for receiving the photoelectric signals receive the reflected photoelectric signals, the controller identifies the signals of the photoelectric elements, and the controller outputs control signals to start the paying-off mechanism.

15. A lawnmower according to claim 9, wherein: the detection module comprises a Hall sensor, and the Hall sensor is arranged on the detection module,

the grass mowing line has magnetism, when the grass mowing line passes through the sensing range of the Hall sensor, the Hall sensor senses the magnetism of the grass mowing line, when the grass mowing line is abraded to reach or exceed a set length,

the Hall sensor can not detect the magnetic signal of the grass mowing line, and the controller outputs a control signal to start the paying-off mechanism according to the signal of the Hall sensor.

16. A lawnmower according to claim 9, wherein: the detection module comprises a color recognition sensor, the color recognition sensor can recognize the color of the grass mowing line, when the abrasion of the grass mowing line reaches or exceeds a set length, the color recognition sensor cannot recognize the color of the grass mowing line, and a controller outputs a control signal to start the paying-off mechanism according to the signal of the color recognition sensor.

17. A lawnmower according to claim 1, wherein: the pay-off mechanism comprises at least one pay-off electronic switch, and the pay-off electronic switch can selectively start the pay-off mechanism according to the comparison result.

18. A lawnmower according to claim 1, wherein: the pay-off mechanism is selectively started according to the comparison result to release the grass mowing line, so that the grass mowing length is increased to a target length, the detection module also detects a parameter reflecting whether the grass mowing length reaches the target length, and the controller outputs a control signal according to the parameter reflecting whether the grass mowing length reaches the target length to selectively stop the pay-off action of the pay-off mechanism.

19. A lawnmower according to claim 1, wherein: and for each comparison result, the pay-off mechanism executes the pay-off action at most once.

20. A lawnmower according to claim 1, wherein: the grass trimmer also comprises an adjusting mechanism with preset parameters, and the preset parameters can be adjusted through the adjusting mechanism.

21. A lawnmower according to claim 1, wherein: the paying-off mechanism also comprises a control device,

the control device comprises a control circuit electrically connected with the motor, and the control circuit is used for controlling the motor to switch between a normal working speed and a pay-off speed.

22. A method of paying off a lawnmower, the lawnmower of claim 1, wherein: the paying-off method comprises the following steps:

s1: detecting a specific parameter reflecting the grass mowing length;

23. A method of paying-off a lawnmower according to claim 22, wherein: if the specific parameter detected in step S1 is a parameter reflecting the workload.

24. A method of paying-off a lawnmower according to claim 23, wherein: if the specific parameter detected in the step S1 comprises the working current of the grass trimmer, the preset parameter comprises a preset current value, the controller compares the working current with the preset current value, and if the working current is smaller than the preset current value, the paying-off mechanism is started in the step S3 to release the grass trimming line.

25. A method of paying-off a lawnmower according to claim 24, wherein: if the parameter detected by the detection module in the step S1 further includes a voltage, the controller calculates the corresponding preset current value according to the voltage.

26. A method of paying-off a lawnmower according to claim 22, wherein: and if the specific parameters detected in the step S1 include the rotating speed of the motor, the preset parameters include a preset motor rotating speed value, the rotating speed is compared with the preset motor rotating speed, and if the rotating speed is greater than the preset motor rotating speed, the paying-off mechanism is started in the step S3 to release the mowing line.

27. A lawnmower according to claim 26, wherein: the parameters detected by the detection module further comprise voltage, and the controller calculates the preset motor rotating speed value through the voltage.

28. A method of paying-off a lawnmower according to claim 22, wherein: the specific parameter detected in the step S1 is specifically a parameter reflecting the actual physical length of the grass length.

29. A method of paying-off a lawnmower according to claim 28, wherein: and if the specific parameters detected in the step S1 comprise photoelectric signals, the preset parameters comprise preset photoelectric signals that the grass mowing length is not worn or the wear does not reach the set length, the photoelectric signals are compared with the preset photoelectric signals, and if the photoelectric signals are different from the preset photoelectric signals, the paying-off mechanism is started in the step S3 to release the grass mowing line.

30. A method of paying-off a lawnmower according to claim 28, wherein: and if the specific parameters detected in the step S1 comprise photoelectric signals and the preset parameters comprise preset photoelectric signals when the grass cutting length is abraded to reach or exceed a set length, comparing the photoelectric signals with the preset photoelectric signals, and if the preset photoelectric signals are the same, starting the pay-off mechanism to release the grass cutting line in the step S3.