JP4982325B2 - Loading platform lifting device - Google Patents

Description

  The present invention relates to a load receiving table lifting device mounted on a truck and used for loading and unloading loads.

For example, the load receiving platform lifting / lowering device supports the load receiving platform at the tip of an arm constituting a parallel link, and lifts and lowers the load receiving platform by a hydraulic cylinder, while the load receiving platform at the rising end position is turned upright by the hydraulic cylinder. There is a so-called stand-up retractable type that is configured to be stored along the side.
In the above-described stand-up storage type load receiving device lifting device, when the load receiving stand is raised to the rising end position or when the load receiving stand is rotated to the stowed storage position, the load receiving stand is moved to the rising end position and the storage position. A stopper is provided so as not to rise or rotate beyond the upper limit, so that the load receiving platform can be stopped at a fixed position. For this reason, when the rising load receiving platform stops at the rising end position, and when the rotating load receiving platform stops at the retracted position, the rising and rotating load receiving platform contacts the stopper, There was a risk of noise.
Here, if the ascending speed and the rotating speed of the cargo cradle are always operated at a low speed, the noise can be suppressed. In this case, however, the time required for the lifting and lowering of the cargo cradle increases and the work efficiency is lowered. End up.
Therefore, in order to reduce the amount of hydraulic oil supplied to the cylinder, a detection sensor is provided for detecting that the load receiving base during the ascending operation or the storing operation has reached just before the ascending end position or just before the storing position. The hydraulic path is switched according to the output signals of these detection sensors and the amount of hydraulic oil supplied is reduced to reduce the operating speed immediately before the load receiving platform reaches the rising end position or the storage position. And measures have been taken to suppress the generation of noise (see, for example, Patent Documents 1 and 2).

Japanese Utility Model Publication No. 51-102107 Utility Model Registration No. 3048767

In the conventional load receiving table lifting device, in order to suppress noise generated in both cases of the lifting operation and the storing operation of the load receiving table, whether or not the load receiving table is positioned immediately before the rising end position is determined. It is necessary to provide both a detection sensor for detecting and a detection sensor for detecting whether or not it is located immediately before the storage position, and the structure as a load receiving table lifting device becomes complicated, and a plurality of The attachment work for attaching the sensor to the apparatus becomes complicated. For this reason, when manufacturing the said receiving stand raising / lowering apparatus, it became a cause of the raise of cost.
The present invention has been made in view of such circumstances. When the rising load receiving platform stops at the rising end position with a simpler configuration and without lowering the work efficiency, the rotating load receiving platform is provided. It is an object of the present invention to provide a load receiving table lifting / lowering device capable of preventing noise generated both when stopping at a storage position.

  The load receiving platform lifting apparatus according to the present invention rotates between a load receiving platform, a lifting device that supports and lifts the load receiving platform by a lifting cylinder, and a retracted position in which the load receiving stand is stood up and a deployed position that is horizontally deployed. Position for detecting that the storage cylinder to be moved, the driving means for driving both cylinders, and the load receiving base are located between the rising end position and a predetermined lifting position below the rising end position. By controlling the detection means and the drive means, a control device for controlling the lifting and turning operations of the cargo cradle and an ascending command for raising the cargo cradle at a predetermined ascent rate are given to the control device. An ascending command output means for outputting and a storage command output means for outputting a storage command for rotating the load receiving table to a storage position at a predetermined rotation speed to the control device, The control device When a rising command is output and the position detecting means detects that the load receiving platform is located between the rising end and the predetermined lift position, the load receiving table is moved from the predetermined rising speed. The speed detecting means for controlling the driving means so as to decelerate, and the position detecting means detect that the load receiving platform is located between the rising end and the predetermined lift position and the storage. An elapsed time determining means for determining whether or not an operation time required for the cargo cradle to rotate to a predetermined rotational position close to the storage position has elapsed since the command was output; and the elapsed time determination A rotation speed reduction means for controlling the drive means so as to decelerate the load receiving table from the predetermined rotation speed when it is determined by the means that the operation time has elapsed. Trying

  According to the load receiving table lifting apparatus configured as described above, when the elapsed time determining means determines that the operation time has elapsed, the drive means is configured to decelerate the load receiving table from a predetermined rotation speed. Since it has a rotation speed decelerating means to control, it is possible to decelerate the load receiving platform immediately before the storage position without providing a sensor for detecting whether the load receiving platform is positioned immediately before the storage position. Can do. For this reason, noise generated both when the rising load receiving platform stops at the rising end position and when the rotating load receiving platform stops at the retracted position is suppressed by a simpler configuration than the conventional example. can do.

The drive means includes a hydraulic pump that supplies hydraulic oil to the cylinders and a motor that drives the hydraulic pump, and the ascending speed reduction means and the rotation speed reduction means include the motor. The amount of oil discharged from the hydraulic pump may be reduced to reduce the ascent speed and the rotational speed of the load receiving table.
In this case, by reducing the amount of oil discharged from the hydraulic pump, the rising speed and turning speed of the load receiving platform are decelerated. For example, the amount of hydraulic oil supplied to the cylinders is reduced in order to reduce the operating speed of both cylinders. Compared to the case where a dedicated hydraulic path is provided, the hydraulic path for supplying hydraulic oil to both cylinders can be simplified. Therefore, speed reduction control of the load receiving platform can be realized while suppressing an increase in the manufacturing cost of the load receiving platform lifting device.

Further, the elapsed time judging means counts the time only while the cargo receiving platform is operating toward the storage position, and judges whether or not the operating time has passed based on this time. Preferably there is.
In this case, the elapsed time judging means counts the time only during the operation of the cargo cradle, so if the operation of the cargo cradle is temporarily stopped during the storage operation of the cargo cradle, the elapsed time judgment is made. Means stop timing. When the cargo cradle starts operating again, the elapsed time judging means adds up to the time when the time measurement was stopped and starts time measurement again. For this reason, since the time during which the cargo cradle is not operating is excluded from the time that is timed, the elapsed time judging means can accurately grasp the time when the cargo cradle actually operates, It can be determined whether or not the operating time has passed.

  As described above, according to the load receiving platform lifting apparatus of the present invention, both when the rising load receiving platform stops at the rising end position and when the rotating load receiving platform stops at the retracted position with a simpler configuration. It is possible to prevent noise generated in

FIG. 1 is a side view of a rear portion of a truck equipped with a load receiving table lifting apparatus according to a first embodiment of the present invention.
In FIG. 1, a cargo box 2 that accommodates luggage is mounted on a body 1 of a truck. The rear end surface of the packing box 2 can be opened and closed by a door 2a. At the rear part of the vehicle body 1, a load receiving table lifting / lowering device 3 for loading and unloading loads is attached. The load receiving platform lifting / lowering device 3 is installed between the load receiving platform 4, a lifting / lowering device 5 that supports and lifts the base end thereof, and the load receiving platform 4 and the lifting / lowering device 5. And a storage cylinder 6 (see also FIG. 2) for standing and storing. The stowage 4 in the retracted state stands vertically along the rear end surface of the packing box 2. From this retracted state, by rotating clockwise about the pivot 15 pin 15 (see also FIG. 2) of the rotation fulcrum located below the rear end face of the cargo box 2, the load receiving platform 4 is moved to two points in the figure. It will be in the state expanded horizontally indicated by a chain line. Further, it is possible to descend from this position until landing while maintaining the level of the load receiving platform 4.

  The structure of the load receiving table lifting device 3 will be described in more detail with reference to FIG. In FIG. 2, the support bracket 7 is fixed to a member 1 a that is fixed to the vehicle body 1 and extends in the vehicle width direction. A vertically long base link 8 is attached to the support bracket 7, and an upper arm 9 is rotatably attached to the base link 8 by a pin 11. The lower arm 10 is attached to the support bracket 7 so as to be rotatable by a pin 12. Further, the piston side end of the elevating cylinder 13 serving as a drive source for the elevating device 5 is pivotally attached to the base link 8 by a pin 14.

  A substantially L-shaped tip arm 9a is integrally fixed to the distal end side of the upper arm 9, so that the end portion of the upper arm 9 as a whole (including the tip arm 9a) protrudes upward. It has a shape. The end of the upper arm 9 and the end of the lower arm 10 are pivotally attached to the link body 17 by pins 15 and 16. Further, the base end portion of the load receiving platform 4 is pivotally attached to the upper arm 9 (the front arm 9 a) and the link body 17 by a pin 15.

Here, the pins 11, 12, 15 and 16 in FIG. 2 constitute the vertices of the parallelogram. That is, the upper arm 9 and the lower arm 10 constitute a parallel link. A lift cylinder 13 is pivotally attached to the upper arm 9 by a pin 18. A driving force is applied between the pin 18 and the pin 14 (FIG. 2) by the expansion / contraction operation of the elevating cylinder 13 so that the parallel link moves up and down while maintaining the horizontal posture of the load receiving table 4. be able to.
Further, the upper arm 9 and the support bracket 7 are provided with stoppers (not shown) for stopping the load receiving platform 4 so as not to rise above the same height position as the floor surface of the load box 2. The load receiving platform 4 can be moved up and down with the height position substantially the same as the floor surface 2b of the packing box 2 as the rising end position (see FIG. 2).

On the other hand, the above-mentioned storage cylinder 6 built in the stiffener 4 a portion of the load receiving platform 4 has the piston rod 6 a at its tip end pivotally attached to the link body 17 by a pin 19. The rear end of the cylinder tube is attached to the stiffener 4a. When the storage cylinder 6 is extended, the load receiving platform 4 is rotated in the upright direction (counterclockwise direction) around the pin 15 to be in the upright and stored state as shown in FIG. Conversely, by retracting the storage cylinder 6 from the stored state of the load receiving table 4, the load receiving table 4 is rotated in the expanding direction (clockwise direction) around the pin 15, and is in a horizontally expanded state at the rising end. In this manner, the storage cylinder 6 can rotate the load receiving table 4 between the storage state and the unfolded state. Further, the link body 17 is provided with a stopper (not shown) for stopping the load receiving platform 4 so that it does not rotate any more when it rotates to the retracted state.
In the following description, in the rotation operation of the load receiving platform 4, the position where the load receiving platform 4 is stood and stored is also referred to as a storage position, and the position where the load receiving platform 4 is deployed horizontally is also referred to as a deployment position.

FIG. 3 is an enlarged view of the vicinity of the base end portion of the upper arm 9. A dog 20 that rotates integrally with the upper arm 9 around the pin 11 is disposed at the base end of the upper arm 9. The dog 20 is a plate-like member, and includes a fixing portion 20a that is fixed to be overlapped with the side surface of the upper arm 9, and a protruding portion 20b that protrudes from the fixing portion 20a along the rotation direction. Yes.
Further, a proximity sensor 21 for detecting the protruding portion 20b of the dog 20 that rotates together with the upper arm 9 is fixed to the upper surface of the member 1a via a bracket 21a. The proximity sensor 21 has a detection range set so as to detect the protruding portion 20b when the upper arm 9 is positioned within a predetermined rotation angle range, and is connected to a control device 60 described later. The detection result is output to the control device 60. The protrusion 20b is detected by the proximity sensor 21 when the load receiving platform 4 is located above a position immediately before the rising end (see FIG. 2) as a predetermined lifting position below the rising end position. The angular width is set, so that it can be detected that the load receiving platform 4 is located between the rising end position and the position immediately before the rising end. That is, the proximity sensor 21 and the dog 20 constitute position detecting means for detecting that the load receiving platform 4 is located between the rising end position and the position immediately before the rising end.

Next, the hydraulic mechanism of the load receiving table lifting device 3 will be described. FIG. 4 is a hydraulic circuit diagram of the load receiving table elevating device 3. In the figure, the hydraulic circuit includes a power unit 51, a pair of elevating cylinders 13, a solenoid valve 52 connected to each elevating cylinder 13, and a pair of storage cylinders 6. The storage cylinder 6 is urged in the contracted direction at the upright storage position by a built-in spring, so that the impact sound generated by the load receiving platform 4 when being stored upright is alleviated to some extent. In the power unit 51, a tank 511, a motor 512, a hydraulic pump 513 driven by the motor 512, a relief valve 514 (set pressure is 20.6 MPa, for example), a check valve 515, an oil return electromagnetic valve 516, a throttle A valve 517, a solenoid valve 518 for driving the storage cylinder 6, a control valve 519 formed by connecting a series body of a check valve and a throttle valve in antiparallel to each other, and filters 520, 521 and 522 are connected as shown in the figure. Has been.
The solenoid valves 516, 518, and 52 are respectively provided with solenoids 516s, 518s, and 52s, and each solenoid is in a communication position in an excited state and is a check valve in a non-excited state.

Next, control of the hydraulic mechanism will be described. FIG. 5 is an electric circuit diagram showing aspects of the power unit 51 and the solenoid.
As shown in the figure, the power unit 51 includes a control device 60 that controls the hydraulic equipment in addition to the hydraulic equipment such as the electromagnetic valves described above, and a motor 512 for operating the in-vehicle battery 70 and the hydraulic pump 513. And a connected FET 53. The FET 53 is connected to the control device 60, and opens and closes an electric circuit between the motor 512 and the in-vehicle battery 70 based on a control signal from the control device 60.

The control device 60 is configured by a microcomputer having a CPU, a memory (RAM), a storage device (hard disk and ROM), and the like, and the like are installed in order to realize a function for performing the control described later. In addition to the FET 53, the control device 60 is connected to the solenoids 516s, 518s, 52s of the solenoid valves 516, 518, 52, and the up switch S1, the down switch S2, the expansion switch S3, and the storage switch S4. Has been. A proximity sensor 21 fixed to the member 1a (FIG. 3) is also connected.
The control device 60 controls the electric power supplied to the motor 512 by controlling the opening and closing of the electric circuit by the FET 53, and the rotation number of the motor 512 is rotated in two ways: a predetermined normal speed and a speed lower than the normal speed. In addition to being able to control the number, the speed of increase / decrease in the number of rotations can be controlled to a predetermined value. The control device 60 closes the electric circuit between the motor 512 and the in-vehicle battery 70 by the FET 53 when the normal speed control for operating the rotation speed of the motor 512 at the normal speed is performed. Further, in the case of low speed control for driving at a low speed, PWM control is performed by opening and closing the FET 53 based on a predetermined parameter, and the amount of electric power supplied to the motor 512 is set so as to achieve the low speed rotation speed. suppress. In addition, when adjusting the speed of increase / decrease in the rotational speed of the motor 512, the amount of electric power supplied to the motor 512 is gradually increased or decreased by PWM control. As a result, the discharge amount of hydraulic oil from the hydraulic pump 513 can be set in two stages, and the increase / decrease speed of the discharge amount can be adjusted.

Further, the control device 60 functionally includes timers T1 and T2 for measuring elapsed time. As will be described later, the timers T1 and T2 are used for control when the cargo receiving platform 4 is moved up and stored. Further, the timers T1 and T2 are configured so as to integrate the elapsed time measured by the timers unless reset.
In addition, the control device 60 includes an ascending speed reduction unit 61, a rotation speed reduction unit 62, and an elapsed time determination unit 63 that are functional units for controlling the operation of the cargo receiver 4. These will be described in detail later.

  Each of the switches S1 to S4 is connected between the control power supply 54 and the control device 60, and outputs a control signal to the control device 60 when turned on. Moreover, each switch S1-S4 is arrange | positioned at the operation surface S5 of the switch box S, as shown in FIG. The switch box S is used by an operator who operates the load receiving platform lifting / lowering device 3 to operate the switches S1 to S4. The switch box S is connected to the power unit 51 via a harness S6 of several meters, for example. Each of the switches S1 to S4 is a push button switch, and is configured to be in an on state while the operator performs a pressing operation and to be in an off state when the pressing operation is released. In addition, the ground symbol in a figure means the connection to the vehicle body as a-side electric circuit.

  The control device 60 is configured to control each hydraulic device based on the operation of each of the switches S1 to S4 so as to realize the expansion / contraction operation of the above-described lifting cylinder 13 and storage cylinder 6. Specifically, the control device 60 controls the motor 512 and the electromagnetic valves 516, 518, and 52 as shown in Table 1 in response to the operations of the switches S1 to S4. In Table 1, ○ means switch-on state, motor operation, excitation of solenoid valve, and x means switch-off state, motor stop, demagnetization of solenoid valve.

That is, when the storage switch S4 is pressed and turned on, the control device 60 starts operation of the motor 512 to generate a predetermined hydraulic pressure and excites the electromagnetic valve 518. Then, the storage cylinder 6 is extended by the hydraulic pressure supplied through the electromagnetic valve 518, and the storage operation for rotating the load receiving table 4 toward the storage position is performed. When the deployment switch S3 is turned on, the control device 60 stops the motor 512, and returns the hydraulic oil fed into the storage cylinder 6 to the tank 511 through the electromagnetic valves 518 and 516 in the communication position state. The retracting operation of rotating the storage cylinder 6 and rotating the load receiving platform 4 to the unfolding position is performed. If the motor 512 is stopped and the solenoid valves 518 and 516 are demagnetized, the hydraulic oil in the storage cylinder 6 is retained, and the storage cylinder 6 maintains that state.
Further, when the ascent switch S1 is turned on, the control device 60 operates the motor 512 to generate a predetermined hydraulic pressure, extends the lifting cylinder 13 through the electromagnetic valve 52 (check valve side), and the load receiving table 4 To raise. When the lowering switch S2 is turned on, the motor 512 is stopped, and the hydraulic oil sent to the elevating cylinder 13 is returned to the tank 511 through the electromagnetic valve 52 and the electromagnetic valve 516 in the communication position, thereby The lifting cylinder 13 to which a load is applied is contracted to lower the load receiving platform 4.

  As described above, the hydraulic mechanism including the motor 512, the hydraulic pump 513, each solenoid valve, and the like shown in FIG. 4 constitutes a drive unit that drives the elevating cylinder 13 and the storage cylinder 6, and the control device 60 Controls the lifting and lowering operations of the load receiving platform 4 by controlling the hydraulic mechanism.

  In addition, the ascending speed reduction unit 61 and the rotation speed reduction unit 62 of the control device 60 perform the normal speed control and the normal speed control as described above based on predetermined conditions when the cargo receiving platform 4 is raised and stored. By switching to one of the low speed controls, the hydraulic oil discharge amount of the hydraulic pump 513 can be set in two stages. Thereby, the extension speed of the storage cylinder 6 and the elevating cylinder 13 can be set in two stages, and the ascent speed of the load receiving platform 4 is a normal speed as a predetermined ascent speed and a speed lower than the normal speed. Can be set to low speed. Moreover, the rotation speed at the time of rotating the cargo receiving stand 4 to the storage position can be set to a normal speed as a predetermined rotation speed and a low speed that is lower than the normal speed.

As described above, the ascending speed reduction unit 61 and the rotation speed reduction unit 62 of the control device 60 reduce the amount of oil discharged from the hydraulic pump 513 when the number of rotations of the motor 512 is switched from the normal speed to the low speed. 4 can be controlled to decelerate the ascending speed and the rotating speed from the normal speed to the low speed.
The ascending speed reduction unit 61 and the rotation speed reduction unit 62 also reduce the ascending speed and the rotation speed of the load receiving table 4 from the normal speed to a lower speed by adjusting the speed of increase / decrease of the rotational speed of the motor 512. You can also
In this case, for example, a hydraulic path for supplying hydraulic oil to both cylinders as compared to a case where a dedicated hydraulic path for reducing the amount of hydraulic oil supplied to the cylinders to reduce the operating speed of both cylinders is provided. Can be configured in a simple manner. Therefore, it is possible to realize control capable of changing the operation speed of the load receiving platform 4 while suppressing an increase in manufacturing cost of the load receiving platform lifting / lowering device 3.

  In addition, the low speed in each of the ascending speed and the rotational speed of the load receiving platform 4 is set to be about 50% of the normal speed, for example, and is normally set as the rotation speed of the motor 512. The relationship between the speed and the low speed is set and controlled so that the low speed of the ascending speed and the rotational speed of the load receiving platform 4 is about 50%.

Next, the control of the lifting operation of the receiving platform 4 performed by the control device 60 will be described in detail.
FIG. 7 is a flowchart showing a processing procedure performed by the control device 60 when raising the unloading stage 4 from the ground to the rising end position.
First, when the operator turns on the ascent switch S1 (step S101), the control device 60 starts timing by the timer T1 that is functionally included in the control device 60 and operates the motor 512 by low-speed control. (Step S102). Thereby, the raising / lowering cylinder 13 starts expansion | extension, and the receiving platform 4 leaves | separates from the ground and starts raising. At this time, since the motor 512 is controlled at a low speed, the ascending speed of the load receiving platform 4 is set to a low speed.

Next, the control device 60 determines whether or not the elapsed time t1 measured by the timer T1 is 3 seconds or more (step S103). When determining that the elapsed time t1 is 3 seconds or longer, the control device 60 sets the control of the motor 512 to the normal speed control (step S104). As a result, the ascending speed of the load receiving platform 4 is set to the normal speed, and the load receiving platform 4 is increased to the normal speed.
In this way, the ascent switch S1 constitutes an ascending command output means for outputting a control signal as an ascending command for raising the load receiving platform 4 at a normal speed to the control device 60 by being turned on. .

  On the other hand, when determining that the elapsed time t1 is less than 3 seconds, the control device 60 determines whether or not the ascent switch S1 is in an on state (step S105). When determining that the ascent switch S1 is not in the ON state, the control device 60 proceeds to step S111, resets the timer T1 (step S111), stops the motor 512 (step S112), and ends the process. That is, when the operator stops the pressing operation to the raising switch S1, the control device 60 stops the motor 512 and stops the raising of the cargo receiving platform 4.

If it is determined in step S105 that the ascent switch S1 is in the ON state, the control device 60 determines whether or not the proximity sensor 21 has detected the dog 20 (step S106). When determining that the proximity sensor 21 detects the dog 20, the control device 60 proceeds to step S109. If it is determined that the dog 20 is not detected, the control device 60 returns to step S103, and if it is determined that the elapsed time t1 is 3 seconds or more, the control device 60 proceeds to step S104 and sets the ascending speed of the receiving platform 4 to the normal speed. To do.
By the above steps S103, S105, and S106, the control device 60 monitors the state of the ascent switch S1 and the detection state of the proximity switch 21 for 3 seconds after the ascent switch S1 is turned on and the loading platform 4 starts to ascend. To do.

Moreover, the control apparatus 60 raises at a low speed for 3 seconds after the load receiving stand 4 starts to rise by the above process, and then raises at a normal speed.
In this case, in the case where the load is raised with the load placed on the load receiving platform 4, the lift can be started at a relatively low speed, so that the swing of the load on the load receiving stand 4 can be reduced and smooth and reliable. You can lift and lower your luggage.

  When the ascending speed of the receiving platform 4 is set to the normal speed in step S104, the control device 60 causes the ascending speed deceleration unit 61 to determine whether or not the proximity sensor 21 has detected the dog 20 (step S107). If it is determined that the dog 20 is not detected, the ascending speed reduction unit 61 determines whether or not the ascending switch S1 is in the on state (step S108). The process proceeds to steps S111 and S112. Then, the control device 60 determines that the operator has stopped pressing the lift switch S <b> 1, stops the motor 512, and stops the lift of the load receiving platform 4. If it is determined in step S108 that the ascent switch S1 is in the on state, the ascending speed reduction unit 61 returns to step S107 again.

While the ascending speed deceleration unit 61 of the control device 60 is processing steps S107 and S108, the cargo receiving platform 4 continues to rise at the normal speed. Then, when the load receiving platform 4 reaches the position immediately before the rising end, the proximity sensor 21 detects the dog 20.
When determining that the proximity sensor 21 detects the dog 20 in step S107, the ascending speed deceleration unit 61 sets the control of the motor 512 to low speed control (step S109). Thereby, since the ascending speed of the cargo receiving platform 4 is set to a low speed, the ascending speed is decelerated.
In this way, the ascending speed reduction unit 61 is positioned between the ascending end and the position just before the ascending end by the proximity sensor 21 and the dog 20 when the ascending command is output in steps S107 to S109. When it is detected, the ascending speed decelerating unit is configured to control the cargo receiving platform 4 to decelerate from the speed FS which is the normal speed.

Next, the control device 60 determines whether or not the ascent switch S1 is in an off state (step S110). If it is not in an off state (in an on state), the control device 60 returns to step S110.
On the other hand, if it is determined that it is in the off state, the process proceeds to steps S111 and S112, where it is determined that the operator has stopped pressing the lift switch S1, and the control device 60 stops the motor 512 and Stop the climb.
In step S110, when the load receiving platform 4 reaches the rising end position and is stopped by the stopper, if the operator stops pressing the lifting switch S1, the load receiving platform 4 is stopped and held at the rising end position.

For example, when the operator stops the pressing operation of the lifting switch S1 during the lifting operation of the cargo receiving table 4 and stops the lifting of the cargo receiving table 4, if the operator presses the lifting switch S1 again, the lifting switch S1. For 3 seconds after turning on, the ascending speed is set to a low speed in step S103 and then set to a normal speed.
In addition, even when the pressing operation of the lifting switch S1 is stopped when the load receiving platform 4 is above the position immediately before the lifting end and the operator presses the lifting switch S1 again, the control device 60 performs the proximity sensor in step S106. Since it is judged that 21 has detected the dog 20, it can recognize that the load receiving stand 4 passes the position just before a raise end, and is higher than it. Thereafter, the control device 60 proceeds to step S109, so that the ascending speed of the cargo receiving platform 4 is set to a low speed.

Next, an operation mode of each part over time when the cargo receiving platform 4 is raised from the ground to the rising end position by the above processing procedure will be described. FIG. 8 is a timing chart showing the operation state of each part when raising the unloading stage 4 from the ground to the rising end position. In FIG. 8, the horizontal axis indicates the elapsed time, and the on / off state of the ascent switch S1, the height position of the load receiving table 4, the detection state of the proximity sensor 21, the terminal voltage of the motor 512, and the ascending speed of the load receiving table 4 are respectively shown. Shown over time.
In FIG. 8, at the timing f0 indicated by the broken line, the ascent switch S1 is in the OFF state, and the control device 60 does not operate the motor 512, so that the terminal voltage is 0V. Further, since the cargo receiving platform 4 is on the ground, the proximity sensor 21 is in a non-detected state and the ascending speed is zero.

When the operator presses the ascent switch S1 at the timing f1 to turn it on, the control device 60 starts the operation of the motor 512 with low speed control. Hereinafter, the case where the raising switch S1 is kept on until the cargo receiving platform 4 reaches the ascending end position and stops will be described.
Here, as described above, the control device 60 performs PWM control by opening and closing the FET 53 based on a predetermined parameter in order to set the rotational speed of the motor 512 to a low speed. For this reason, as shown in the figure, the terminal voltage appears as a pulse-like waveform between a predetermined voltage value that is substantially the voltage value of the in-vehicle battery 70 and 0V. By such control, the amount of power supplied to the motor 512 is suppressed and the rotation of the motor 512 is suppressed as compared with the case of normal speed control in which a predetermined voltage value that is substantially the voltage of the in-vehicle battery 70 is continuously energized. The number can be controlled at a lower speed than the normal speed. Further, since the control is performed at a low speed by the PWM control, heat generation can be suppressed as compared with a case where a voltage is suppressed by using a resistor or the like.
Further, the load receiving platform 4 starts to rise when the motor 512 is controlled at a low speed, and the rising speed is set to a low speed. Therefore, as shown in FIG. 8, the ascending speed of the load receiving platform 4 gradually increases from the timing f0 and reaches a speed LS1 that is a predetermined low speed.

Next, the control device 60 sets the control of the motor 512 to the normal speed control at a timing f2, which is 3 seconds after the timing f1 when the ascent switch S1 is turned on. Therefore, the terminal voltage of the motor 512 appears constant at a predetermined voltage value.
In addition, when the motor 512 is controlled at a normal speed, the ascending speed of the load receiving platform 4 is set to a speed FS1 that is a predetermined normal speed. Therefore, as shown in FIG. 8, the ascending speed of the receiving platform 4 further increases from the speed LS1 and reaches the speed FS1. Since the rising speed of the height position of the load receiving platform 4 increases, the inclination thereof increases as compared with that between the timings f1 and f2.

When the load receiving platform 4 rises at the speed FS1 and reaches the position immediately before the rising end, the proximity sensor 21 detects the dog 20. At the timing f3 when the proximity sensor 21 detects the dog 20, the control device 60 sets the control of the motor 512 to the above-described low speed control. Accordingly, the cargo receiving platform 4 starts to decelerate and decelerates from the speed FS1 to the speed LS1.
Further, the load receiving platform 4 rising at the speed LS1 is stopped by the stopper when reaching the rising end position at the timing f4, so that the rising speed becomes zero. When the load receiving table 4 reaches the rising end position, the operator releases the pressing operation of the lift switch S1 (timing f5), so that the terminal voltage of the motor 512 becomes 0V, the motor 512 stops, and the load receiving table 4 , Stopped and held at the rising end position.
The speed LS1, which is the ascending speed of the load receiving platform 4, is set to a speed that does not generate a large noise when the load receiving platform 4 moves up to reach the rising end position and stops by the stopper.

  As described above, the control device 60 of the load receiving platform lifting / lowering device 3 according to the present embodiment allows the load receiving platform 4 to be positioned between the rising end and the position immediately before the rising end by the proximity sensor 21 and the dog 20 when the lifting command is output. If it is detected that the load is received, the load receiving platform 4 is controlled to decelerate from the speed FS which is the normal speed. As a result, it is possible to suppress the noise that is generated when the rising receiving platform 4 stops at the rising end position.

Next, the control of the storage operation of the receiving platform 4 performed by the control device 60 will be described in detail.
FIG. 9 is a flowchart showing a processing procedure performed by the control device 60 when the load receiving platform 4 in the deployed state (deployed position) at the rising end position is rotated to the retracted position.
First, when the operator presses the storage switch S4 (step S201), the control device 60 determines whether or not the proximity sensor 21 detects the dog 20 (step S202). If it is determined that the dog 20 has not been detected, the control device 60 ends the process. This is because if the proximity sensor 21 does not detect the dog 20, the load receiving platform 4 is not located at the rising end position.

On the other hand, when determining that the dog 20 is detected, the control device 60 determines whether or not the elapsed time t2 counted by the timer T2 that is functionally included is less than 3 seconds (step S203). ). When determining that the elapsed time t2 is not less than 3 seconds, the control device 60 proceeds to step S213. Step S213 will be described later.
If it is determined that the elapsed time t2 is not less than 3 seconds, the control device 60 starts the time measurement by the timer T2 that it has functionally, and causes the motor 512 to start operation by the normal speed control (step S204). ).

Next, the control device 60 excites the solenoid 518s and switches the electromagnetic valve 518 to the communication position (step S205). As a result, the storage cylinder 6 starts to extend, and the load receiving platform 4 starts to rotate from the deployed position toward the stored position. At this time, since the motor 512 is controlled at a normal speed, the rotation speed of the load receiving platform 4 is set to the normal speed.
In this way, the storage switch S4 is provided with storage command output means for outputting a control signal as a storage command for rotating the load receiving platform 4 to the storage position at the normal speed to the control device 60 when the storage switch S4 is turned on. It is composed.

Next, the control device 60 determines whether or not the storage switch S4 is in an off state (step S206). When determining that the storage switch S4 is in the OFF state, the control device 60 proceeds to step S210, stops the timer T2 (step S210), closes the electromagnetic valve 518 (step S211), and stops the motor 512 (step S212). ).
On the other hand, when determining that the storage switch S4 is not in the OFF state, the control device 60 causes the elapsed time determination unit 63 to determine whether or not the elapsed time t2 measured by the timer T2 is 3 seconds or more (step S207). . If it is determined that the elapsed time t2 is not 3 seconds or more, the elapsed time determination unit 63 returns to step S206.
When determining that the elapsed time t2 is 3 seconds or more, the control device 60 causes the rotation speed reduction unit 62 to set the control of the motor 512 to be the low speed control (step S208). As described above, in steps S206 and S207, the control device 60 determines whether or not the storage switch S4 is in the OFF state for 3 seconds after the storage switch S4 is turned on and the cargo receiving table 4 starts to rotate. To monitor. When the elapsed time t2 of the timer T2 becomes 3 seconds or more, the motor 512 is controlled at a low speed, and the rotation speed of the load receiving platform 4 is set to a low speed, so that the rotation speed is reduced. If the pressing operation of the storage switch S4 is released before the elapsed time t2 becomes 3 seconds or more, the motor 512 is stopped and the rotation of the cargo receiving platform 4 is stopped.

Further, the normal speed, which is the rotational speed of the cargo cradle 4, is immediately before storing as a predetermined rotational position close to the storage position shown in FIG. 1 when the cargo cradle 4 is continuously rotated for 3 seconds from the deployed position. The value that reaches the position is set.
That is, the elapsed time determination unit 63 and the timer T2 of the control device 60 indicate that the load receiving platform 4 is located between the position immediately before the rising end and the rising end based on the elapsed time t2 measured by the timer T2. The operation time required for the load receiving platform 4 to rotate to the position immediately before the storage from the time when the control signal is detected (step S202) and the storage switch S4 is pressed and stored (step S201). It is determined whether or not a certain 3 seconds have passed (step S207).
Further, the rotation speed reduction unit 62 controls the rotation speed of the load receiving platform 4 so as to reduce the rotation speed from the normal speed to the low speed when the elapsed time determination unit 63 determines that the operation time has elapsed. The speed reduction means is constituted.

When the control of the motor 512 is set to the low speed control in step S208, the control device 60 next determines whether or not the storage switch S4 is in the OFF state (step S209). If it is determined that the storage switch S4 is not in the OFF state, the process returns to step S209 again to repeat the determination as to whether or not the storage switch S4 is in the OFF state.
On the other hand, when determining that the storage switch S4 is in the OFF state, the control device 60 proceeds to step S210, stops the timer T2 (step S210), closes the electromagnetic valve 518 (step S211), and stops the motor 512 ( Step S212). Thereby, the cargo receiving stand 4 stops rotating at the current position.
In step S209, when the load receiving table 4 reaches the storage position and is stopped by the stopper, if the operator stops pressing the storage switch S4, the load receiving table 4 is stopped and held at the storage position.

  In FIG. 9, when it is determined in step S203 that the elapsed time t2 is not less than 3 seconds, the control device 60 starts counting by the timer T2 and starts operating the motor 512 by the low speed control. (Step S213), the process proceeds to Step S209. Note that, as described above, the timer T2 is configured to accumulate the elapsed time t2 counted by the timer T2 unless reset, so that, for example, the storage switch S4 is operated while the load receiving table 4 is being stored by the operator. When the storage switch S4 is pressed again after the storage switch S4 is operated from the unfolded position, the load reception base 4 rotates to perform the storage operation. It is possible to time the operation time performed.

Further, the control device 60 rotates the load receiving table 4 while the storage switch S4 is pressed in steps S206, S207, and S209, and stops the rotation of the load receiving table 4 when the pressing operation is released. Is configured to do.
For this reason, the timer T2 is configured to count the elapsed time t2 only while the storage switch S4 is pressed and the load receiving platform 4 is rotating to the storage position.
Accordingly, when the pressing operation of the storage switch S4 is released and the rotation of the load receiving table 4 is stopped during the storing operation of the load receiving table 4, the timer T2 stops counting the elapsed time t2. When the storage switch S4 is pressed again to start rotating, the timer T2 adds up to the elapsed time when the time measurement is stopped and starts counting the elapsed time t2 again. For this reason, the elapsed time t2 excludes the time during which the load receiving table 4 is not rotating, so that the timer T2 can accurately measure the time during which the load receiving table 4 actually operates. The elapsed time determination unit 63 can determine more accurately whether or not the operation time has elapsed.

Further, when the operator releases the pressing operation of the storage switch S4 and stops the rotation of the load receiving table 4, and then presses the storage switch S4 again to rotate the load receiving table 4, the control device 60 By determining whether or not the elapsed time t2 is less than 3 seconds in step S203, it is possible to determine whether or not the cargo receiving platform 4 has reached the position immediately before storage.
Accordingly, if it is determined that the position just before the storage has not been reached, the receiving platform 4 can be rotated at a normal speed, and if it is determined that the position immediately before the storage has been reached, it can be rotated at a low speed.

  The timer T2 is configured to be reset when the lowering switch S2 and the deployment switch S3 are pressed. Therefore, when the operator operates the storage switch S4 in order to store the consignment table 4, the timer T2 is reset in the work of the previous stage.

Next, a description will be given of the operation of each part over time when the receiving platform 4 is stored from the deployed position to the stored position by the above processing procedure. FIG. 10 is a timing chart showing the operation state of each part when the cargo receiving platform 4 is stored from the deployed position to the stored position. In FIG. 10, the horizontal axis indicates the elapsed time. The storage switch S4 is turned on / off, the position (angle) of the load receiving table 4, the detection state of the proximity sensor 21, the terminal voltage of the motor 512, and the rotation speed of the load receiving table 4 Are shown over time.
In FIG. 10, at the timing f <b> 6 indicated by the broken line, the storage switch S <b> 4 is in the OFF state, and the control device 60 does not operate the motor 512, so the terminal voltage is 0V. Further, since the load receiving platform 4 is in the unfolded position and in the raised end position, the proximity sensor 21 is in the detection state and the rotation speed is zero.

When the operator depresses the storage switch S4 at the timing f7 to turn it on, the control device 60 starts the operation of the motor 512 by normal speed control. Hereinafter, a case will be described in which the storage switch S4 is kept on until the cargo receiving platform 4 reaches the storage position and stops.
In this case, the terminal voltage of the motor 512 appears constant at a predetermined voltage value. The load receiving platform 4 starts rotating by the normal speed control of the motor 512, and the rotating speed is set to the normal speed. Therefore, as shown in FIG. 10, the rotational speed of the load receiving platform 4 gradually increases from the timing f7 and reaches a speed FS2 that is a predetermined normal speed.
Next, the control device 60 sets the control of the motor 512 to the low speed control at the timing f8 that is 3 seconds after the timing f7 when the storage switch S4 is turned on. Accordingly, the terminal voltage of the motor 512 appears as a pulse-like waveform between the predetermined voltage value and 0 V, as in FIG. Further, the angle of the load receiving platform 4 reaches the position immediately before the storage (see FIG. 1) at the timing f8.

The load receiving platform 4 starts to decelerate when the motor 512 is set to the low speed control, and decelerates until the rotation speed becomes a predetermined low speed LS2.
Further, when the load receiving platform 4 that rotates at the speed LS2 reaches the storage position at the timing f9, the load receiving platform 4 comes into contact with and stops at the load box, the stopper, and the like, so the rotation speed becomes zero. When the load receiving platform 4 reaches the storage position, the operator releases the pressing operation of the storage switch S4 (timing f10), so that the terminal voltage of the motor 512 becomes 0V, and the motor 512 stops.
Note that the speed LS2, which is the rotational speed of the load receiving platform 4, is set to a speed that does not generate a large noise when the load receiving platform 4 rotates and reaches the storage position and stops by the stopper.

  According to the load receiving table lifting / lowering device 3 configured as described above, it is detected that the load receiving table 4 is positioned between the position immediately before the rising end and the rising end, and the storage switch S4 is pressed to store. When the elapsed time determination unit 63 determines that the operation time required for the load receiving platform 4 to rotate to the position immediately before the storage has elapsed since the control signal indicating that the load receiving platform 4 has been output is turned. Since it has the rotation speed reduction part 62 which controls a hydraulic mechanism so that a speed may be set to a low speed from a normal speed, it will detect whether the load receiving stand 4 is located in the position just before storage. Without providing a sensor for this, the load receiving platform 4 can be decelerated immediately before the storage position. For this reason, noise generated both when the rising cradle 4 stops at the rising end position and when the rotating cradle 4 stops at the retracted position with a simpler configuration as compared with the conventional example. Can be suppressed.

In particular, when providing a sensor or the like for determining whether or not the load receiving platform 4 has reached the position immediately before storage, it is necessary to lay wiring for connecting the sensor or to finely adjust the mounting position. The attaching operation is very complicated. On the other hand, in the load receiving table elevating device 3 of this embodiment, it is not necessary to provide a sensor for determining whether or not the load receiving table 4 has reached the position immediately before storage. The number of man-hours can be reduced, and the cost can be reduced.
Moreover, in the load receiving platform lifting / lowering device 3 of the present embodiment, the load receiving platform 4 rising at the normal speed can be decelerated from the position immediately before the rising end, and the load receiving platform 4 rotating toward the storage position at the normal speed is further provided. The vehicle can be decelerated from the position immediately before storage. In other words, since the decelerating table 4 operating at the normal speed is decelerated immediately before it is stopped, the work efficiency is not lowered as compared with the case where all of the operations of the receiving table 4 are performed at a low speed.

FIG. 11 is a hydraulic circuit diagram of the load receiving table lifting apparatus according to the second embodiment of the present invention. The difference between the present embodiment and the first embodiment is that the electromagnetic mechanism disposed between the adjustment valve 519 and the electromagnetic valve 518 in the hydraulic mechanism as the driving means for driving the elevating cylinder 13 and the storage cylinder 6. A valve 531, a flow control valve 532 disposed in a bypass path provided via the solenoid valve 531, a solenoid valve 533 disposed between the solenoid valve 52 and the check valve 515, and the solenoid valve 533 And a flow control valve 534 disposed in the bypass path provided.
That is, in the first embodiment, the control device 60 controls the rotational speed of the motor 512 and adjusts the discharge pressure of the hydraulic pump 513 in order to set the ascending speed and the rotational speed of the load receiving platform 4 in two stages. However, in the present embodiment, the control device 60 controls the switching to the bypass path in which the flow control valves 532 and 533 are arranged. For this reason, in this embodiment, the motor 512 is set to a predetermined rotational speed, and the hydraulic pump 513 discharges hydraulic oil with a constant hydraulic pressure.

The solenoid valve 531 can be controlled by the control device 60 in the same manner as the other solenoid valves. When the solenoid 531s is not excited, the adjustment valve 519 arranges the hydraulic path from the hydraulic pump 513 to the storage cylinder 6. In the case of the excitation state, it connects to the bypass route to which the flow control valve 532 is connected.
Here, the flow control valve 532 is set so as to reduce the flow rate of hydraulic oil to the storage cylinder 6 rather than the adjustment valve 519. Therefore, when the solenoid valve 531 is excited and switched to the bypass path side, the flow rate of the hydraulic oil supplied to the storage cylinder 6 is reduced as compared with the normal path. Thus, in the present embodiment, the flow rate of the hydraulic oil supplied to the storage cylinder 6 can be adjusted in two stages by switching the electromagnetic valve 531.

Further, the solenoid valve 533 can also be controlled by the control device 60. When the solenoid 533s is not excited, the hydraulic path from the hydraulic pump 513 to the lift cylinder 13 is connected to the normal path that is directly connected, and excited. In the case of a state, it connects to the bypass path to which the flow control valve 534 is connected.
Therefore, when the solenoid valve 533 is excited and switched to the bypass path side, the flow rate of the hydraulic oil supplied to the lift cylinder 13 is reduced as compared with the normal path. The flow rate of the hydraulic oil supplied to the cylinder 13 can be adjusted in two stages.

In the load receiving platform elevating device 3 having the above-described configuration, the control device 60 controls the solenoid valves 531 and 533 so that the flow rate of hydraulic oil supplied to the storage cylinder 6 and the elevating cylinder 13 can be adjusted in two stages. The extension speeds of the storage cylinder 6 and the lifting cylinder 13 are set in two stages. As a result, the ascending speed of the load receiving platform 4 can be set to a normal speed as a predetermined ascent speed and a low speed that is lower than the normal speed. Moreover, the rotation speed at the time of rotating the cargo receiving stand 4 to the storage position can be set to a normal speed as a predetermined rotation speed and a low speed that is lower than the normal speed.
Therefore, also in the load receiving platform elevating device 3 of the present embodiment, when the rising load receiving platform 4 stops at the rising end position and the rotating load receiving platform 4 stops at the retracted position, as in the first embodiment. Noise generated at both times can be suppressed.
The flow rate settings of the adjustment valve 519 and the flow control valves 532 and 534 and the discharge pressure of the hydraulic oil of the hydraulic pump 513 are set to predetermined ascending speeds and rotation speeds for the storage cylinder 6 and the lifting cylinder 13 respectively. Adjusted to The electromagnetic valves 531 and 533 are connected to the control device 60 and controlled to be switched at the switching timing between the normal speed and the low speed described in the above-described embodiment.

  As described above, in the load receiving table lifting device of the present invention, the control device 60 controls the hydraulic mechanism so as to decelerate the ascending speed and the rotation speed of the load receiving table 4 from the normal speed to the low speed. It can also be configured.

In addition, the load receiving table lifting / lowering device of the present invention is not limited to the above embodiment. In the above-described embodiment, the time required to reach the position immediately before storage is set to 3 seconds when the load receiving table 4 in the unfolded position rotates at the normal speed (speed FS2). The speed is appropriately changed according to the speed FS2 set as the rotation speed.
The position immediately before the rising end is set according to the normal speed (speed FS1) and the low speed (speed LS1) set as the rising speed, and the distance between the rising end position and the rising end position is , It is set to such an extent that it can be surely decelerated before reaching the rising end position. The same applies to the position immediately before the storage position, and the distance between the position immediately before storage and the storage position depends on the normal speed (speed FS2) and the low speed (speed LS2) set as the rotation speed. It is set to such an extent that it can be surely decelerated before reaching.

Further, by appropriately setting parameters (duty, frequency, etc.) in PWM control of the motor 512, the speed of increase / decrease of the rotational speed of the motor 512 is adjusted, and the speed of increase / decrease of the load receiving platform 4 and the speed of increase / decrease of the rotational speed are adjusted. You can also
FIG. 12 shows another aspect of the timing chart when raising the unloading cradle from the ground to the rising end position. In this case, in the acceleration section in which the ascending / descending speed of the load receiving platform 4 is increased to the normal speed and the deceleration section in which the lifting speed is decelerated from the normal speed, the ascending / descending speed of the load receiving platform 4 is increased and decelerated so as to change smoothly as shown in the figure. In addition, the rotational speed of the motor 512 is controlled.
In this case, noise generated when the load receiving platform 4 stops can be more effectively suppressed, and shaking of the load on the load receiving platform 4 when the load receiving platform 4 is raised with the load loaded thereon can be further reduced.

  Moreover, in the said embodiment, although it comprised so that the raising / lowering of the load receiving stand 4 and an expansion | deployment storage operation might be performed by operating each switch S1-S4, it replaced with the expansion | deployment switch S3 and the storage switch S4, for example, The rotation switch S7 may be provided. In this case, on the operation surface S5 of the switch box S, as shown in FIG. 13, a total of three switches, that is, the up / down switches S1, S2 and the rotation switch S7 are arranged. In this case, it is configured to output a storage command for rotating to the storage position to the control device 60 by simultaneously pressing the up switch S1 and the rotation switch S7. By simultaneously pressing the switch S7, a deployment command for rotating the load receiving platform 4 from the storage position to the deployment position is output to the control device 60.

It is the figure which looked at the rear part of the lorry equipped with the load receiving table raising / lowering device by a first embodiment of the present invention from the side. It is a side view which shows the raising / lowering operation | movement of a cargo receiving stand raising / lowering apparatus. It is an enlarged view of the base end part periphery of an upper arm. It is a hydraulic circuit diagram of the load receiving table lifting device. It is the electric circuit diagram which showed aspects, such as a power unit and a solenoid. It is an external view of a switch box. It is the flowchart which showed the process sequence which a control apparatus performs when raising the load receiving stand of an unfolded state from the ground to a raise end position. It is the timing chart which showed the operation state of each part at the time of raising the load receiving stand of a deployment state from the ground to a raise end position. It is the flowchart which showed the process sequence which a control apparatus performs when rotating the load receiving stand in a deployment state (deployment position) in a raise end position to a storage position. It is a timing chart which showed the operation state of each part at the time of carrying out storage operation of a receiving stand from a deployment position to a storage position. It is a hydraulic circuit figure of the load receiving table raising / lowering apparatus which concerns on 2nd embodiment of this invention. The other aspect of the timing chart at the time of raising the load receiving stand of an unfolded state from the ground to a raise end position is shown. It is an external view which shows the other aspect of a switch box.

Explanation of symbols

Reference Signs List 3 Loading platform lifting device 4 Loading platform 5 Lifting device 6 Storage cylinder 13 Lifting cylinder 20 Dog (position detection means)
21 Proximity sensor (position detection means)
60 Control Device 61 Ascending Speed Deceleration Unit 62 Rotation Speed Deceleration Unit 63 Elapsed Time Judgment Unit 512 Motor 513 Hydraulic Pump S1 Ascent Switch (Upward Command Output Unit)
S4 Storage switch (storage command output means)
T2 timer

Claims (3)

A cradle,
A lifting device that supports and lifts the load receiving table by a lifting cylinder;
A storage cylinder that rotates between a storage position in which the load receiving stand is erected and a deployment position in which it is deployed horizontally;
Drive means for driving both cylinders;
Position detecting means for detecting that the load receiving platform is located between the rising end position and a predetermined lifting position below the rising end position;
A control device that controls the lifting and lowering operations of the load receiving table by controlling the driving means; and
An ascending command output means for outputting an ascending command for raising the cargo receiving platform at a predetermined ascending speed to the control device;
A storage command output means for outputting, to the control device, a storage command for rotating the load receiving table to a storage position at a predetermined rotation speed;
When the control device detects that the ascending command is output and the position detecting means detects that the load receiving platform is located between the rising end and the predetermined lift position, the control device Ascending speed deceleration means for controlling the driving means to decelerate from the predetermined ascent speed;
The load receiving platform is close to the stored position when the position detecting means detects that the load receiving table is positioned between the rising end and the predetermined lift position and the storage command is output. An elapsed time determining means for determining whether or not an operation time required to rotate to a predetermined rotation position has elapsed;
A rotation speed reduction means for controlling the drive means so as to decelerate the load receiving table from the predetermined rotation speed when the elapsed time determination means determines that the operation time has elapsed. A cargo receiving platform lifting device. The drive means includes a hydraulic pump that supplies hydraulic oil to the cylinders, and a motor that drives the hydraulic pump,
The ascending speed decelerating means and the rotating speed decelerating means reduce the amount of oil discharged from the hydraulic pump by decreasing the number of rotations of the motor, thereby decelerating the ascending speed and the rotating speed of the load receiving platform, respectively. The load receiving table lifting device according to claim 1.   The elapsed time judging means counts the time only while the consignment base is operating toward the storage position, and judges whether or not the operating time has passed based on this time. 2. The cargo receiving platform lifting apparatus according to 2.

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