JP7516141B2 - Weight measuring device for construction machinery and construction machinery - Google Patents

Description

The present invention relates to a weight measuring device installed in a construction machine, and a construction machine equipped with the gravity measuring device.

Patent Document 1 discloses a construction machine in which a clamshell bucket is suspended from the front end of a boom that can be raised and lowered. In this construction machine, the clamshell bucket is used to excavate a load such as soil and sand, and the load is deposited inside the clamshell bucket. The load is then transferred from the clamshell bucket to a transport vehicle such as a truck.

JP 2002-173947 A

In construction machines such as those described in Patent Document 1, from the standpoint of improving work efficiency and preventing overloading of the load on the transport vehicle, it is required that the worker properly grasp the weight of the load piled up in the clamshell bucket and the total weight of the load loaded on the transport vehicle.

The present invention has been made to solve the above problems, and its purpose is to provide a weight measuring device for a construction machine that can properly grasp the weight of the load in the clamshell bucket and the total weight of the load in the transport vehicle. It is also an object of the present invention to provide a construction machine equipped with the weight measuring device.

In order to achieve the above object, one aspect of the present invention is a weight measuring device provided on a construction machine in which a clamshell bucket driven by an operating force transmitted via a rope paid out from a winch is suspended from a front end of a boom that can be raised and lowered, the weight measuring device including a sheave around which the rope is hung between the winch and the front end of the boom, a shaft extending along a central axis and supporting the sheave rotatably about the central axis, a first hydraulic cylinder attached to one end of the shaft in a direction along the central axis, a second hydraulic cylinder attached to the shaft at an end opposite to the first hydraulic cylinder in the direction along the central axis, and a load-bearing member for each of the first hydraulic cylinder and the second hydraulic cylinder. the controller calculates the load acting on the sheave based on the pressure detection result by the sensor in response to an input of a measurement command, and calculates the load acting on the rope based on the load acting on the sheave, measures the weight of the load piled up in the clamshell bucket as a subtraction value obtained by subtracting the weight of the clamshell bucket from the calculated load on the rope, and notifies a transport vehicle other than the construction machine of the measured weight of the load in the clamshell bucket and the sum of the weights of the loads loaded from the clamshell bucket.

According to the present invention, it is possible to provide a weight measuring device for a construction machine that can properly grasp the weight of the load in the clamshell bucket and the total weight of the load in the transport vehicle. It is also possible to provide a construction machine equipped with the weight measuring device.

FIG. 1 is a schematic diagram illustrating an example of a crane according to a first embodiment. FIG. 2 is a schematic diagram showing the front end of the boom of the crane of FIG. 1 as viewed in the direction of arrow H. FIG. 3 is a perspective view that shows a schematic configuration of a sheave (guide sheave) attached to the rear end of the boom in the crane of FIG. 1 and the surrounding area. FIG. 4 is a schematic diagram showing a sheave (guide sheave) attached to the rear end of the boom and the configuration in the vicinity thereof in the crane of FIG. 1, as viewed from one side in the width direction of the rotating body. FIG. 5 is a block diagram illustrating a control system of the weight measuring device according to the first embodiment. FIG. 6 is a schematic diagram showing an example of a display on a display unit of a user interface of the weight measuring device according to the first embodiment. FIG. 7 is a flowchart showing a process of measuring the weight of a loaded object, which is performed by the controller of the weight measuring device according to the first embodiment. FIG. 8 is a flowchart showing a process for measuring the load acting on the rope in FIG.

The following describes the embodiment with reference to the drawings.

First Embodiment
In the first embodiment, a crane will be described as an example of a construction machine. Fig. 1 shows an example of a crane 1 according to this embodiment. As shown in Fig. 1, the crane 1 includes a lower traveling body 2 and an upper rotating body 3 connected to the lower traveling body 2 from the vertically upper side. A cab 5 is provided on the upper rotating body 3. The upper rotating body 3 can rotate relative to the lower traveling body 2 around a rotation axis along the vertical direction. In addition, a boom 6 is connected to the upper rotating body 3. The boom 6 can rotate integrally with the upper rotating body 3 relative to the lower traveling body 2.

In addition, the boom 6 has a longitudinal direction (direction indicated by arrows X1 and X2). In addition, in the boom 6, one side of the longitudinal direction is the front side (arrow X1 side), and the opposite side to the front side is the rear side (arrow X2 side). The boom 6 is attached to the upper rotating body 3 at the rear end. In addition, the boom 6 can be raised and lowered relative to the upper rotating body 3. Therefore, in the boom 6, a (vertical or approximately vertical) raising and lowering direction (direction indicated by arrows Y1 and Y2) that intersects with the longitudinal direction is specified. By raising or lowering the boom 6 relative to the upper rotating body 3, the raising and lowering angle θ of the boom 6 with respect to the horizontal plane changes. In addition, in the boom 6, a (vertical or approximately vertical) width direction (direction perpendicular or approximately perpendicular to the paper surface of FIG. 1) that intersects with both the longitudinal direction and the raising and lowering direction is specified. The width direction of the boom 6 coincides or approximately coincides with the width direction of the upper rotating body 3. In addition, the boom 6 can be extended and retracted in the longitudinal direction. When the boom 6 extends or retracts, the boom length in the longitudinal direction of the boom changes.

2 shows the front end of the boom 6 as viewed from the direction of the arrow H in FIG. 1, that is, from the front side of the boom 6. In FIG. 2, the direction indicated by the arrows W1 and W2 is the width direction of the boom 6. The upper rotating body 3 is provided with winches 11 and 21. The winch 11 is provided with a rope 12. The rope 12 is extended from the rear end (base end) of the boom 6 to the front end (tip end) along the longitudinal direction of the boom 6. In the boom 6, the rope 12 is extended along the top surface of the boom, which is the end surface on the side where the boom 6 is raised (arrow Y1 side). As shown in FIG. 1 and FIG. 2, etc., the upper rotating body 3 is provided with a sheave 13, and the front end of the boom 6 is provided with sheaves 24 and 25. The rope 12 extended from the winch 11 is hung on the sheave 13, and then hung on the sheaves 24 and 25 in that order. In addition, the rope 12 is guided to the winch 11 by a sheave 13.

A rope 22 is paid out from the winch 21. The rope 22 is extended along the longitudinal direction of the boom 6 from the rear end to the front end of the boom 6. The rope 22 is extended along the top surface of the boom 6. A sheave (guide sheave) 23 is attached to the rear end of the boom 6, and sheaves 14 and 15 are attached to the front end of the boom 6. The rope 22 paid out from the winch 21 is hung on the sheave 23, and then hung on the sheaves 14 and 15 in that order. The rope 22 is guided to the winch 21 by the sheave 23.

The ropes 12 and 22 are connected to the clamshell bucket 60. The clamshell bucket 60 includes a top frame 61, a lower frame 62, and a pair of clamshells 65 and 66. The lower frame 62 is disposed vertically below the top frame 61. The top frame 61 is provided with a bracket 63 that protrudes vertically upward, and a sheave 67 is attached to it. A sheave 68 is attached to the lower frame 62. The pair of clamshells 65 and 66 are connected to the top frame 61 and the lower frame 62 in a state in which they can be opened and closed relative to each other.

The rope 12 is connected to a bracket 63 on the top frame 61 of the clamshell bucket 60. Therefore, the clamshell bucket 60 is suspended from a sheave 25 at the front end of the boom 6 via the rope 12. In the crane 1, the clamshell bucket 60 moves vertically upward by winding the rope 12 onto the winch 11. On the other hand, in the crane 1, the clamshell bucket 60 moves vertically downward by letting out the rope 12 from the winch 11.

The rope 22 is hung from the sheave 15 at the front end of the boom 6 to each of the sheaves 67, 68 of the clamshell bucket 60 multiple times, and then connected to the bracket 63 of the top frame 61 from below vertically. In the crane 1, the pair of clamshells 65, 66 in the clamshell bucket 60 close relative to each other by winding the rope 22 onto the winch 21. On the other hand, in the crane 1, the pair of clamshells 65, 66 in the clamshell bucket 60 open relative to each other by unwinding the rope 22 from the winch 21. Therefore, the operating force that drives the clamshell bucket 60 is transmitted via the rope 22.

In operations using the crane 1, the clamshell bucket 60 is moved downward close to the ground, and the clamshells 65, 66 are opened and closed to excavate the load, such as soil and sand. This causes the load to pile up inside the clamshell bucket 60. In operations using the crane 1, the clamshell is moved with the load piled up inside the clamshell bucket 60 to the vicinity of the bed of a transport vehicle other than the crane 1, such as a truck. Then, the clamshells 65, 66 are opened with the clamshell bucket 60 positioned close to the bed of the transport vehicle, and the load is loaded from the clamshell bucket 60 onto the bed of the transport vehicle.

In addition, a winch 71 is installed in front of the cab 5 on the upper rotating body 3 of the crane 1, and a rope 72 is paid out from the winch 71. In addition, a sheave 73 is attached to the underside of the boom 6, which is the end face of the side where the boom 6 is lowered (the side of the arrow Y2). The rope 72 is hung on the sheave 73 and connected to the clamshell bucket 60. The rope 72 prevents the clamshell bucket 60 from rotating and vibrating.

Figures 3 and 4 show the sheave 23 attached to the rear end of the boom 6 and the configuration in the vicinity thereof. Figure 3 shows a perspective view with the rope 22 omitted. Also, Figure 4 shows the state as viewed from one side in the width direction of the upper rotating body 3, and the state as viewed from one side in the width direction of the boom 6. Note that in Figure 3, the direction indicated by the arrows W1 and W2 is the width direction of the boom 6, and in Figure 4, the direction perpendicular or approximately perpendicular to the paper surface is the width direction of the boom 6.

As described above, the rope 22 that is reeled out from the winch 21 is hung on the sheave (guide sheave) 23 between the winch 21 and the front end of the boom 6. As shown in Figures 3 and 4, the sheave 23 is attached to the rear end of the boom 6 via a shaft 31 and a bracket 32. The bracket 32 is directly attached to the boom 6. The bracket 32 is rotatable relative to the boom 6 around a rotation axis P1 formed at the attachment position (connection position) to the boom 6. The rotation axis P1 of the bracket 32 relative to the boom 6 is along the width direction of the boom 6.

The bracket 32 also has a pair of plate-shaped portions 35A, 35B. The plate-shaped portions 35A, 35B are arranged apart from each other in the width direction of the boom 6. The bracket 32 is attached to the boom 6 in a state in which the boom 6 is sandwiched between the plate-shaped portions 35A, 35B in the width direction of the boom 6. The sheave 23 is attached to the bracket 32 via the shaft 31. The shaft 31 and the sheave 23, together with the bracket 32, are rotatable about the rotation axis P1 relative to the boom 6.

The shaft 31 has a central axis P2 and extends along the central axis P2. The shaft 31 is attached to the bracket 32 with the central axis P2 aligned along the width direction of the boom 6. One end of the shaft 31 in the direction along the central axis P2 is connected to the plate-shaped portion 35A of the bracket 32, and the other end of the shaft 31 in the direction along the central axis P2 is connected to the plate-shaped portion 35B of the bracket 32. The sheave 23 is supported by the shaft 31 so as to be rotatable about the central axis P2 of the shaft 31. The sheave 23 is movable along the central axis P2 of the shaft 31 relative to the shaft 31. That is, the sheave 23 is movable along the width direction of the boom 6 relative to the shaft 31 and the bracket 32.

The crane 1 of this embodiment is equipped with a weight measuring device 40. The weight measuring device 40 measures the load T acting on the rope 22, i.e., the tension acting on the rope 22. In the crane 1 described above, the magnitude of the load T acting on the rope 22 is equal to or approximately equal to the sum of the weight Ta of the clamshell bucket 60 and the weight Tb of the load piled up in the clamshell bucket 60. Therefore, in the crane 1 of this embodiment, the weight measuring device 40 measures the sum of the weight Ta of the clamshell bucket 60 and the weight Tb of the load in the clamshell bucket 60. The weight measuring device 40 is equipped with the sheave (guide sheave) 23, shaft 31, and bracket 32 described above.

The weight measuring device 40 also includes a pair of hydraulic cylinders 37A, 37B. Each of the hydraulic cylinders 37A, 37B has a cylinder axis (one of Qa and Qb) as a central axis, and each of the hydraulic cylinders 37A, 37B can be extended and retracted along the cylinder axis (one of Qa and Qb). One end of each of the hydraulic cylinders 37A, 37B is connected to the upper rotating body 3. The other end of the hydraulic cylinder (first hydraulic cylinder) 37A is connected to the shaft 31 via the plate-shaped portion 35A of the bracket 32. Therefore, the hydraulic cylinder 37A is attached to one end of the shaft 31 in the direction along the central axis P2 (the width direction of the boom 6). The other end of the hydraulic cylinder (second hydraulic cylinder) 37B is connected to the shaft 31 via the plate-shaped portion 35B of the bracket 32. Therefore, the hydraulic cylinder 37B is attached to the shaft 31 at the end opposite the mounting position of the hydraulic cylinder 37A in the direction along the central axis P2 (the width direction of the boom 6).

In the crane 1, the weight of the load in the clamshell bucket 60 changes, and the load T acting on the rope 22 changes, causing the load F acting on the sheave 23 from the rope 22 to change. In addition, the change in load F causes the load Ra acting on the hydraulic cylinder 37A and the load Rb acting on the hydraulic cylinder 37B to change, causing the hydraulic pressure of each of the hydraulic cylinders 37A and 37B to change.

Here, the distance La from the pivot axis P1 of the bracket 32 to the central axis P2 of the shaft 31 (the rotation axis of the sheave 23), and the distance Lb from the pivot axis P1 of the bracket 32 to the cylinder axis Qa of the hydraulic cylinder 37A and the cylinder axis Qb of the hydraulic cylinder 37B are specified. In this embodiment, the distance from the pivot axis P1 to the cylinder axis Qa of the hydraulic cylinder 37A and the distance from the pivot axis P1 to the cylinder axis Qb of the hydraulic cylinder 37B are the same at the distance Lb. The distances La and Lb are values that do not change even if the elevation state of the boom 6 changes. In addition, the opening angle α of the rope 22 at the contact point with the sheave 23 is specified. The opening angle α is the angle formed by the imaginary line M1 along the extension direction of the rope 22 from the front end of the boom 6 to the sheave 23 and the imaginary line M2 along the extension direction of the rope from the winch 21 to the sheave 23. The opening angle α changes in response to changes in the elevation state of the boom 6, i.e., in response to changes in the elevation angle θ of the boom 6 described above.

In addition, the bisector Mα of the opening angle α is specified, and the distance Lα from the pivot axis P1 of the bracket 32 to the bisector Mα is specified. Here, the angle between the imaginary line M1 and the bisector Mα, and the angle between the imaginary line M2 and the bisector Mα are α/2. In addition, the total load value R, which is the sum of the load Ra of the hydraulic cylinder 37A and the load Rb of the hydraulic cylinder 37B, is specified. When the parameters are specified as described above, the relationship between the distance La and the distance Lα is expressed by equation (1) using the opening angle α. In addition, from the balance of the moment around the axis of the pivot axis P1 of the bracket 32, the relationship between the total load value R and the load F acting on the sheave 23 is expressed by equation (2) using the distances Lb and Lα. And the relationship between the load F acting on the sheave 23 and the load T (the load of the suspended load) acting on the rope 22 is expressed by equation (3) using the opening angle α. In addition, FIG. 4 shows the cylinder axes Qa, Qb, distances La, Lb, Lα, imaginary lines M1, M2, opening angle α, and bisector Mα, as well as loads Ra (Rb), F, and T.

Lα=La×sin(α/2) (1)
R×Lb=F×La (2)
F=T×cos(α/2) (3)

Therefore, by detecting the load Ra of hydraulic cylinder 37A and the load Rb of hydraulic cylinder 37B, the total load value R is calculated, and the load F acting on the sheave 23 can be calculated using the calculated total load value R and equation (2) etc. Then, the load T acting on the rope 22 can be calculated using the calculated load F and equation (3). Therefore, in the crane 1, the load T acting on the rope 22 can be measured based on the load Ra of hydraulic cylinder 37A and the load Rb of hydraulic cylinder 37B.

Figure 5 shows an example of a control system of the weight measuring device 40. The weight measuring device 40 includes a controller 41. The controller 41 constitutes, for example, a computer, and includes a processor or integrated circuit (control circuit) including a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array), and a storage medium such as a memory. The number of processors or integrated circuits provided in the controller 41 may be one or more. The controller 41 performs processing by executing a program or the like stored in a storage medium or the like.

The weight measuring device 40 also includes pressure sensors (sensors) 42A and 42B. The pressure sensor 42A detects the pressure (hydraulic pressure) acting on the hydraulic cylinder (first hydraulic cylinder) 37A. The pressure sensor 42B detects the pressure (hydraulic pressure) acting on the hydraulic cylinder (second hydraulic cylinder) 37B. The controller 41 obtains the load Ra acting on the hydraulic cylinder 37A from the pressure detection result by the pressure sensor 42A, and obtains the load Rb acting on the hydraulic cylinder 37B from the pressure detection result by the pressure sensor 42B.

The weight measuring device 40 also includes a user interface 43. The user interface 43 includes an operating member, and an operation command is input by an operator or the like through the operating member. Examples of the operating member include a button, a dial, a touch panel, and a remote control, and in one example, the operating member is provided inside the cab 5. In the example of FIG. 5, buttons 45 and 46 are provided as the operating members. The controller 41 performs processing based on the command input through the operating member. The user interface 43 also includes a notification unit that notifies the operator or the like of information. The notification unit notifies the operator or the like by displaying a screen, emitting a sound, turning on a light, or the like. In the example of FIG. 5, the notification unit includes a display unit 47 that is provided inside the cab 5. In this embodiment, the crane 1 also includes an angle sensor 48. The angle sensor 48 detects the hoisting angle θ of the boom 6. The controller 41 obtains information on the hoisting state of the boom 6, including the hoisting angle θ of the boom 6, from the detection result of the angle sensor 48.

Figure 6 shows an example of the display on the display unit 47 of the user interface 43 of the weight measuring device 40. In the example of Figure 6, a button 51 is displayed on the display unit 47. The display unit 47 is provided with information display areas 52 and 53. The information display area 52 shows the weight Tb of the load piled up inside the clamshell bucket 60. The information display area 53 shows the total weight (accumulated value) N of the load loaded from the clamshell bucket 60 to the transport vehicle. In the display unit 47, the information display areas 52 and 53 are arranged in positions next to each other. Therefore, in the display unit 47, the weight Tb of the load in the clamshell bucket 60 and the total weight N of the load in the transport vehicle are displayed next to each other. In addition, the display unit 47 displays a display indicator 55. In the display unit 47, the display indicator 55 lights up to warn that the total weight N of the load in the transport vehicle has reached the allowable weight Nth.

Figure 7 shows the process of measuring the weight of a load, which is performed by the controller 41 of the weight measuring device 40. The process shown in Figure 7 is performed periodically at a predetermined interval by the controller 41 during the work of loading a load such as soil and sand onto a transport vehicle such as a truck using a clamshell bucket 60.

As shown in FIG. 7, in the process of measuring the weight of the loaded object, the controller 41 determines whether or not a weight update command, which is a command to update the weight Ta of the clamshell bucket 60, has been input (S101). In one example, the weight update command is input by pressing the button 51 on the display unit 47 of the user interface 43. If a weight update command has not been input (S101-No), the process proceeds to S103.

On the other hand, when a weight update command is input (S101-Yes), the controller 41 updates the weight Ta of the clamshell bucket (S102). At this time, in one example, when no load is piled up in the clamshell bucket 60, that is, when the weight Tb of the load piled up in the clamshell bucket 60 is 0, the load T acting on the rope 22 is measured in the same manner as the processing of S105 described later. Then, the measured load T is obtained as the weight Ta of the clamshell bucket 60. In another example, the weight Ta of the clamshell bucket 60 is input by an operator or the like in the user interface 43. Then, the input value in the user interface 43 is obtained as the weight Ta of the clamshell bucket 60. The controller 41 also stores the updated weight Ta in a storage medium or the like. Then, the controller 41 resets the weight Tb of the load in the clamshell bucket 60 to 0 based on the input of the weight update command. After performing step S102, processing proceeds to step S103.

In S103, the controller 41 determines whether or not a measurement command has been input to measure the weight Tb of the load piled up in the clamshell bucket 60. In one example, the measurement command is input by pressing the button 45 of the user interface 43. If a measurement command has not been input (S103-No), the process proceeds to S107. On the other hand, if a measurement command has been input (S103-Yes), the controller 41 performs a process of measuring the load T acting on the rope 22 (S104).

Figure 8 shows the measurement process of the load T acting on the rope 22 in Figure 7. As shown in Figure 8, in the measurement process of the load T, the controller 41 acquires the boom 6's hoisting angle θ from the detection result of the angle sensor 48 (S121). Then, the controller 41 calculates the aforementioned opening angle α of the rope 22, and calculates the distance Lα from the rotation axis P1 of the bracket 32 to the bisector Mα (S122). Here, the opening angle α changes in response to the change in the boom 6's hoisting angle θ. Information (tables, functions, etc.) showing the relationship between the hoisting angle θ and the opening angle α is stored in the storage medium of the controller 41. The controller 41 calculates the opening angle α based on the acquired hoisting angle θ and the information showing the relationship between the hoisting angle θ and the opening angle α. Then, the controller 41 calculates the distance Lα using the calculated opening angle α and the aforementioned formula (1), etc. The distance La from the rotation axis P1 of the bracket 32 to the center axis P2 of the shaft 31 is stored in a storage medium or the like.

The controller 41 obtains the load Ra acting on the hydraulic cylinder 37A from the pressure sensor 42A detecting the pressure of the hydraulic cylinder 37A, and obtains the load Rb acting on the hydraulic cylinder 37B from the pressure sensor 42B detecting the pressure of the hydraulic cylinder 37B (S123). The controller 41 then calculates the total load R, which is the sum of the load Ra of the hydraulic cylinder 37A and the load Rb of the hydraulic cylinder 37B (S124). The controller 41 then calculates the load F acting on the sheave 23 from the rope 22 using the calculated total load R and the above-mentioned formula (2) (S125). As a result, the load F is calculated based on the detection results of the pressure sensors 42A and 42B. The distances Lb from the pivot axis P1 of the bracket 32 to the cylinder axis Qa of the hydraulic cylinder 37A and the cylinder axis Qb of the hydraulic cylinder 37B are stored in a storage medium or the like.

The controller 41 then calculates the load (tension) T acting on the rope 22 based on the calculated load F acting on the sheave 23 (S126). In this manner, in this embodiment, the sum of the weight Ta of the clamshell bucket 60 and the weight Tb of the load piled up in the clamshell bucket 60 is calculated. The load T is calculated using the above-mentioned formula (3). In this manner, the load T acting on the rope 22 is measured as the sum of the weight Ta of the clamshell bucket 60 and the weight Tb of the load piled up in the clamshell bucket 60.

Then, when the measurement process of the load T (S104) is completed, the controller 41 acquires the weight Ta of the clamshell bucket 60 stored in a storage medium or the like. Then, the controller 41 calculates and measures the weight Tb of the load piled up in the clamshell bucket 60 by subtracting the weight Ta of the clamshell bucket 60 from the measured load T of the rope 22 (S105). At this time, the controller 41 stores the measured weight Tb in a storage medium or the like. Then, the controller 41 notifies the measured weight Tb of the load in the clamshell bucket 60 and the total weight N of the load loaded from the clamshell bucket 60 to the transport vehicle to which the load is to be loaded (S106). At this time, the controller 41, for example, displays the weight Tb in the information display area 52 of the display unit 47 and displays the total N in the information display area 53 of the display unit 47. The total weight N of the cargo loaded from the clamshell bucket 60 onto the transport vehicle is stored in a storage medium, etc. After processing S106, the process proceeds to S107.

In S107, the controller 41 determines whether a sum update command has been input, which is a command to update the sum N of the weights of the loads loaded from the clamshell bucket 60 onto the transport vehicle. In one example, the sum update command is input by pressing the button 46 of the user interface 43. If a sum update command has not been input (S107-No), the process proceeds to S113.

On the other hand, when a total sum update command is input (S107-Yes), the controller 41 adds the weight Tb of the load in the clamshell bucket 60 in the most recent measurement to the total sum N of the weight of the load in the transport vehicle (S108). As a result, the controller 41 updates the total sum (accumulated value) N of the weight of the load in the transport vehicle to the sum obtained by adding the weight Tb of the load in the clamshell bucket 60 in the most recent measurement. After updating the total sum N, the controller 41 resets the weight Tb of the load in the clamshell bucket 60 to 0 (S109). The controller 41 also notifies the user of the updated total sum N (S110). At this time, the controller 41 may also notify the user of the reset weight Tb together with the total sum N. For example, the controller 41 displays the updated total sum N in the information display area 53 of the display unit 47, and displays the reset weight Tb in the information display area 52 of the display unit 47. The controller 41 also stores the updated sum N in a storage medium or the like. After performing the process of S110, the process proceeds to S111.

In S111, the controller 41 determines whether the updated sum N is equal to or greater than the allowable weight Nth of the load on the transport vehicle. The allowable weight Nth is pre-stored in a storage medium or the like, or is input by an operator or the like via the user interface 43. If the sum N of the weights of the load on the transport vehicle is smaller than the allowable weight Nth (S111-No), the process proceeds to S113. On the other hand, if the sum N is equal to or greater than the allowable weight Nth (S111-Yes), the controller 41 issues a warning that the sum N of the weights of the load on the transport vehicle has exceeded the allowable weight Nth (S112). In one example, the display indicator 55 of the display unit 47 lights up to warn that the sum N of the weights of the load on the transport vehicle has exceeded the allowable weight Nth. After the process of S112 is performed, the process proceeds to S113.

In S113, the controller 41 determines whether a reset command has been input to reset the sum N to 0. In one example, the reset command is input by simultaneously pressing buttons 45 and 46 of the user interface 43. If a reset command has been input (S113-Yes), the controller 41 resets the sum N of the weights of the loads in the transport vehicle to 0 (S114).

When loading a load such as soil and sand onto a transport vehicle using a clamshell bucket 60, a new clamshell bucket 60 is hung from the front end of the boom 6 via the rope 12, and the rope 22 is connected to the clamshell bucket 60, and the worker inputs a weight update command via the button 51 on the display unit 47. At this time, the weight update command is input when no load is piled up in the clamshell bucket 60. This causes the controller 41 to obtain the weight Ta of the newly hung clamshell bucket 60. In addition, the weight Tb is reset to 0 by inputting the weight update command. When the weight Tb shown in the information display area 52 is 0.2 t, for example, and a weight update command is input, the weight Tb shown in the information display area 52 is switched to 0 t.

In addition, when the load is excavated by the clamshell bucket 60 and the load is piled up in the clamshell bucket 60, the worker or the like inputs a weight update command via the button 45 or the like. This causes the controller 41 to measure the weight Tb of the load piled up in the clamshell bucket 60 as described above. Here, assume that when the weight Tb shown in the information display area 52 is 0t, a measurement command is input and the measured value of weight Tb is 5t. In this case, based on the input of the measurement command, the weight Tb shown in the information display area 52 switches from 0t to 5t.

Furthermore, at the time or immediately after loading the cargo piled up in the clamshell bucket 60 onto the transport vehicle, the worker or the like inputs a total sum update command via button 46 or the like. This causes the controller 41 to add the most recently measured weight Tb of the cargo in the clamshell bucket 60 to the total sum N of the weights of the cargo on the transport vehicle. The controller 41 then resets weight Tb to 0. Therefore, when a total sum update command is input when the weight Tb shown in the information display area 52 is 5t and the total sum N shown in the information display area 53 is 0t, the weight Tb shown in the information display area 52 switches to 0t, and the total sum displayed in the information display area 53 switches to 5t. Furthermore, when the weight Tb shown in the information display area 52 is 5t and the sum N shown in the information display area 53 is 5t, if a command to update the sum is input, the weight Tb shown in the information display area 52 will change to 0t and the sum displayed in the information display area 53 will change to 10t.

In addition, when changing the transport vehicle to which the load is to be transferred from the clamshell bucket 60, the worker inputs a reset command via buttons 45, 46, etc. This causes the controller 41 to reset the total weight N of the load on the transport vehicle to 0. For example, when a reset command is input when the total weight N shown in the information display area 53 is 10 t, etc., the total weight N shown in the information display area 53 switches to 0 t.

In this embodiment, the controller 41 measures the weight Tb of the load piled up in the clamshell bucket 60 by subtracting the weight Ta of the clamshell bucket 60 from the measured load T of the rope 22. Therefore, the weight Tb of the load piled up in the clamshell bucket 60 is measured appropriately. Also, in this embodiment, based on the input of a measurement command, the controller 41 notifies the measured weight Tb of the load in the clamshell bucket 60 and the total weight N of the load loaded from the clamshell bucket 60 to the transport vehicle. Therefore, the worker, etc. can properly grasp the weight Tb and the total weight N. In other words, the worker, etc. can properly grasp the information of the load already loaded on the transport vehicle and the information of the load to be loaded on the transport vehicle.

By having the worker etc. properly grasp the weight Tb and the sum N, overloading of the load onto the transport vehicle is effectively prevented, and the work efficiency of loading the load onto the transport vehicle using the clamshell bucket 60 is improved. In addition, by having the worker etc. grasp the weight Tb of the load excluding the weight Ta of the clamshell bucket 60, excessive loading of the load onto the clamshell bucket 60 is effectively prevented.

In addition, in this embodiment, the weight Tb of the load in the clamshell bucket 60 and the total weight N of the load in the transport vehicle are displayed next to each other on the display unit 47. This allows the worker or the like to easily grasp the weight Tb and the total weight N while operating in the cab 5.

In addition, in this embodiment, the controller 41 updates the sum N of the weights of the load on the transport vehicle by adding the most recently measured weight Tb to the sum N based on the input of a sum update command. The updated sum N is then notified to the worker, etc. This allows the worker, etc. to properly understand the updated sum N. Also, by inputting a sum update command at the time the load accumulated in the clamshell bucket 60 is loaded onto the transport vehicle or immediately thereafter, the updated sum N becomes an appropriate value.

In addition, in this embodiment, if the sum N is equal to or greater than the allowable weight Nth, the controller 41 issues a warning that the sum N of the weights of the loads on the transport vehicle has exceeded the allowable weight Nth. This makes it easier for workers and others to recognize that the load on the transport vehicle is overloaded.

In addition, in this embodiment, the controller 41 resets the total weight N of the load on the transport vehicle to 0 based on the input of a reset command. Therefore, when changing the transport vehicle to which the load is to be loaded from the clamshell bucket 60, an operator or the like can input a reset command, and the total weight N will become an appropriate value even for the changed transport vehicle.

In the weight measuring device 40 of this embodiment, as described above, the sheave 23 around which the rope 22 is hung is supported by the shaft 31 so as to be rotatable around the central axis P2 of the shaft 31. A hydraulic cylinder 37A is attached to one end of the shaft 31 in the direction along the central axis P2, and a hydraulic cylinder 37B is attached to the shaft 31 at the end opposite the hydraulic cylinder 37A in the direction along the central axis P2. The weight measuring device 40 calculates the load T acting on the rope 22 as described above based on the detection results of the pressures of the hydraulic cylinders 37A and 37B. Therefore, the load T acting on the rope 22 is measured without complicating the configuration of the weight measuring device 40, and the weight Tb of the load in the clamshell bucket 60 is measured.

In addition, in the weight measuring device 40 of this embodiment, even if the drive of the winch 21 is stopped and the payout and winding operations of the rope 22 are stopped, the load Ra acts on the hydraulic cylinder 37A and the load Rb acts on the hydraulic cylinder 37B. Therefore, even if the drive of the winch 21 is stopped, the load T acting on the rope 22 is properly measured based on the loads Ra and Rb. Therefore, even if the drive of the winch 21 is stopped, the weight Tb and the sum N are properly calculated.

(Modification)
Construction machines other than the crane 1 may also be provided with a weight measuring device 40 similar to that of the above-described embodiment, etc., and the weight Tb may be measured and the sum N may be calculated in the same manner as in the above-described embodiment, etc. In this case as well, the weight Tb and the sum N are notified by the controller 41.

The present invention is not limited to the above-described embodiment, and various modifications can be made in the implementation stage without departing from the gist of the invention. In addition, the embodiments may be implemented in combination as appropriate as possible, in which case the combined effects can be obtained. Furthermore, the above-described embodiment includes inventions at various stages, and various inventions can be extracted by appropriate combinations of the multiple constituent elements disclosed.

1...Crane, 2...Lower running structure, 3...Upper rotating structure, 6...Boom, 21...Winch, 22...Rope, 23...Sheave, 31...Shaft, 32...Bracket, 37A, 37B...Hydraulic cylinder, 40...Weight measuring device, 41...Controller, 42A, 42B...Pressure sensor, 43...User interface, 47...Display unit, 60...Clamshell bucket.

Claims (4)

A weight measuring device provided on a construction machine in which a clamshell bucket driven by an operating force transmitted via a rope paid out from a winch is suspended from a front end of a boom that can be raised and lowered,
a sheave through which the rope is hung between the winch and the front end of the boom;
A shaft extending along a central axis and supporting the sheave so as to be rotatable about the central axis;
a first hydraulic cylinder attached to one end of the shaft in a direction along the central axis;
a second hydraulic cylinder attached to the shaft at an end opposite to the first hydraulic cylinder in the direction along the central axis;
a sensor for detecting a pressure acting on each of the first hydraulic cylinder and the second hydraulic cylinder;
A controller that acquires a detection result of the pressure by the sensor;
Equipped with
The controller:
In response to an input of a measurement command, a load acting on the sheave is calculated based on the detection result of the pressure by the sensor, and the load acting on the rope is calculated based on the load acting on the sheave.
The weight of the clamshell bucket is subtracted from the calculated load of the rope to obtain a weight of the load piled up in the clamshell bucket.
a total weight of the load in the clamshell bucket and the weight of the load loaded from the clamshell bucket to a transport vehicle other than the construction machine is notified to the transport vehicle .
Weight measuring device. The weight measuring device of claim 1, wherein the controller updates the sum of the weights of the loads in the transport vehicle by adding the weight of the loads in the clamshell bucket in the most recent measurement to the sum of the weights of the loads in the transport vehicle based on the input of a sum update command, and notifies the user of the updated sum. 3. The weight measuring device according to claim 1, further comprising a display unit that displays the measured weight of the load in the clamshell bucket and the sum of the measured weights of the load in the transport vehicle side by side by the controller. A weight measuring device according to any one of claims 1 to 3 ,
An upper rotating body on which the winch is provided;
A lower traveling body to which the upper rotating body is rotatably connected from a vertically upper side;
The boom is connected to the upper rotating body so as to be able to rise and fall, and is capable of rotating together with the upper rotating body relative to the lower traveling body;
The rope that is paid out from the winch;
The clamshell bucket is suspended from the front end of the boom and driven by the operating force transmitted via the rope;
A construction machine equipped with the above.