Dump truck

Abstract

To assist in accurately measuring the loading weight of a dump truck comprising a lock mechanism capable of locking and unlocking the load-carrying tray as the load-carrying tray rotates.SOLUTION: A dump truck 1 comprises: a load-carrying tray 30 coupled rotatably to the rear part of a vehicle body 1A; a weight measurement device 70 which measures the loading weight of the load-carrying tray 30 based upon a hydraulic value of a hydraulic cylinder 25 when the load-carrying tray 30 is inclined; lock mechanisms 50, 60 which lock the load-carrying tray 30 when the load-carrying tray 30 is in a horizontal position; and a notification device 72 which gives notice when the angle of inclination of the load-carrying tray 30 when the loading weight of the load-carrying tray 30 is measured is less than a predetermined lower-limit angle.SELECTED DRAWING: Figure 13

Description

Technical Field

[0001] The present invention relates to a dump truck capable of measuring the loading weight of a load box.

Background Art

[0002] Conventionally, as described in, for example, Patent Document 1, there is known a dump truck that tilts a load box and measures the loading weight based on the load of the load box at that time. This type of dump truck includes a hinge shaft that rotatably supports the rear part of the load box and a pressure receiving device that receives the load of the load box, and calculates the loading weight based on the load received by the pressure receiving device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the load box is tilted, the load of the load box is supported by both the pressure receiving device and the hinge shaft. The smaller the tilt angle of the load box, the relatively larger the load received by the pressure receiving device, and the relatively smaller the load received by the hinge shaft. Therefore, in order to more accurately measure the loading weight based on the load received by the pressure receiving device, it is preferable that the tilt angle of the load box at the time of measurement is small. In addition, when the tilt angle of the load box increases, the loaded goods may move downward and rearward in the load box. As a result, the load received by the pressure receiving device changes, and it may be difficult to obtain an accurate loading weight. From this also, it is preferable that the tilt angle of the load box at the time of measurement is small.

[0005] By the way, the inventor of the present application considered providing a lock mechanism that is turned on and off as the loading box rotates for a dump truck that measures the loading weight based on the load received by the pressure receiving device. For example, when the loading box is rotated from the horizontal position to the inclined position, the engagement between the member on the loading box side and the member on the vehicle body side is released, so that the lock is automatically released. When the loading box is returned from the inclined position to the horizontal position, an automatic lock mechanism that is automatically locked when the above two members are engaged was considered. However, when a lock mechanism is provided in the above dump truck, it was found that there are the following problems.

[0006] When the inclination angle of the loading box is small, the member on the loading box side and the member on the vehicle body side are in contact with each other, and the loading box receives an external force through these members. Therefore, when measuring the loading weight of the loading box, in addition to the weight of the load on the loading box, an external force from the lock mechanism may act on the pressure receiving device. As a result, it may be difficult to obtain an accurate loading weight.

[0007] The present invention has been made in view of such a point, and an object thereof is to assist in accurately measuring the loading weight in a dump truck provided with a lock mechanism capable of measuring the loading weight based on the load of the loading box and locking and unlocking the loading box as the loading box rotates.

Means for Solving the Problems

[0008] The dump truck according to the present invention includes a vehicle body, a loading box rotatably connected to the rear of the vehicle body and rotatable between a horizontal position and an inclined position, a pressure receiving device connected to the loading box and receiving the load of the loading box, a weight measuring device that measures the loading weight of the loading box based on the load of the loading box received by the pressure receiving device when the loading box is inclined, a locking mechanism that locks the loading box when the loading box is in the horizontal position, and a notification device that gives a notification when the inclination angle of the loading box when measuring the loading weight of the loading box is less than a predetermined lower limit angle. Here, the locking of the loading box includes both preventing the loading box from rotating with respect to the vehicle body and preventing a part of the loading box from moving with respect to another part of the loading box.

[0009] According to the above dump truck, when the inclination angle of the loading box when measuring the loading weight of the loading box is relatively small, the pressure receiving device may receive a load caused by the locking mechanism in addition to the load due to the loading weight of the loading box. Due to the influence of the locking mechanism, there is a possibility that the loading weight cannot be accurately measured. However, according to the above dump truck, when the inclination angle of the loading box when measuring the loading weight is less than the lower limit angle, a notification is given. Therefore, the measurer is urged to increase the inclination angle of the loading box. According to the above dump truck, inaccurate measurement of the loading weight is suppressed, so it is easy for the measurer to perform accurate measurement.

[0010] The locking mechanism may include a first sliding member movably supported on one of the vehicle body and the cargo box and movable between a locked position and an unlocked position, a biasing member that biases the first sliding member toward the locked position or the unlocked position, and a second sliding member provided on the other of the vehicle body and the cargo box. The locking mechanism may be configured such that, when the cargo box rotates from a horizontal position to an inclined position, the first sliding member slides relative to the second sliding member and moves from the locked position to the unlocked position, thereby unlocking the cargo box, and, when the cargo box rotates toward the horizontal position, the first sliding member slides relative to the second sliding member and moves from the unlocked position to the locked position, thereby locking the cargo box.

[0011] In the locking mechanism, the first sliding member and the second sliding member slide against each other as the box rotates, thereby locking or unlocking the box. Therefore, when the inclination angle of the box is relatively small, the first sliding member and the second sliding member come into contact with each other, and the box may be subjected to an external force from the locking mechanism. When the inclination angle of the box is relatively small, the pressure-receiving device may be subjected to a load caused by the locking mechanism in addition to a load corresponding to the load weight. When the locking mechanism has the above configuration, the aforementioned effects are significantly exhibited.

[0012] The locking mechanism may be configured such that the first sliding member is spaced apart from the second sliding member when the inclination angle of the packing box is equal to or greater than a predetermined angle, and the lower limit angle may be the predetermined angle.

[0013] As a result, if the first sliding member and the second sliding member are in contact with each other when measuring the load weight of the shipping box, a notification is issued. The measurer is prompted to rotate the shipping box to an inclination angle at which the first sliding member and the second sliding member move away from each other. In other words, the measurer is prompted to tilt the shipping box until the load caused by the locking mechanism is eliminated. This makes it easier for the measurer to accurately measure the load weight.

[0014] The lock mechanism may be configured such that the first sliding member is separated from the second sliding member when the tilt angle of the load box is equal to or greater than a predetermined angle. The notification device may be further configured to issue a notification when the tilt angle of the load box when measuring the loading weight of the load box is greater than a predetermined upper limit angle that is greater than the predetermined angle.

[0015] The greater the tilt angle of the load box, the relatively greater the load received by the rear part of the vehicle body, and the relatively smaller the load received by the pressure receiving device. In a method of measuring the loading weight based on the load received by the pressure receiving device, if the tilt angle is too large, it is difficult to obtain an accurate loading weight. According to the dump truck described above, when the tilt angle of the load box when measuring the loading weight of the load box is greater than the upper limit angle, a notification is issued. Therefore, the measurer is urged to reduce the tilt angle of the load box. Since inaccurate measurement due to too large a tilt angle is suppressed, the measurer can easily perform accurate measurement.

[0016] The lock mechanism may be configured such that the first sliding member is separated from the second sliding member when the tilt angle of the load box is equal to or greater than a predetermined angle. The weight measuring device may be configured to measure the loading weight of the load box based on a load obtained by adding a correction value predetermined according to the tilt angle of the load box to the load of the load box received by the pressure receiving device when the tilt angle of the load box is less than the predetermined angle when measuring the loading weight of the load box.

[0017] In the above dump truck, when the tilt angle of the load box is less than the predetermined angle, the first sliding member and the second sliding member are in contact with each other, and the pressure receiving device may receive a load caused by the lock mechanism. However, in that case, the weight measuring device measures the loading weight of the load box based on a load obtained by adding a correction value predetermined according to the tilt angle of the load box to the load of the load box received by the pressure receiving device. Therefore, the influence of the load caused by the lock mechanism can be reduced, and the loading weight can be measured more accurately.

[0018] Another dump truck according to the present invention includes a vehicle body, a loading box rotatably connected to the rear of the vehicle body and rotatable between a horizontal position and an inclined position, a pressure receiving device connected to the loading box and receiving the load of the loading box, a weight measuring device for measuring the loading weight of the loading box based on the load of the loading box received by the pressure receiving device when the loading box is inclined, and a locking mechanism for locking the loading box when the loading box is in the horizontal position. The weight measuring device is configured to measure the loading weight of the loading box based on the load obtained by adding a correction value predetermined according to the inclination angle of the loading box to the load of the loading box received by the pressure receiving device when the inclination angle of the loading box is less than a predetermined angle when measuring the loading weight of the loading box.

[0019] The locking mechanism may include a first sliding member movably supported on one of the vehicle body and the loading box and movable between a locking position and an unlocking position, a biasing member for biasing the first sliding member toward the locking position or the unlocking position, and a second sliding member provided on the other of the vehicle body and the loading box. The locking mechanism is configured such that when the loading box rotates from the horizontal position toward the inclined position, the first sliding member moves from the locking position to the unlocking position while sliding with respect to the second sliding member, thereby unlocking the loading box, and when the loading box rotates toward the horizontal position, the first sliding member moves from the unlocking position to the locking position while sliding with respect to the second sliding member, thereby locking the loading box.

[0020] In the above dump truck, when the inclination angle of the loading box is less than a predetermined angle, the pressure receiving device may receive a load caused by the locking mechanism. However, in that case, the weight measuring device measures the loading weight of the loading box based on the load obtained by adding a correction value predetermined according to the inclination angle of the loading box to the load of the loading box received by the pressure receiving device. Therefore, the influence of the load caused by the locking mechanism can be reduced, and the loading weight can be measured more accurately.

[0021] One of the first sliding member and the second sliding member may have a curved surface inclined with respect to a horizontal plane and a vertical plane, and the other of the first sliding member and the second sliding member may have a roller that rolls on the curved surface.

[0022] The pressure receiving device may be a hydraulic cylinder that rotates the load box. The weight measuring device may be configured to measure the loading weight of the load box based on the hydraulic pressure value of the hydraulic cylinder.

[0023] Thereby, the loading weight of the load box can be measured by using a hydraulic cylinder that rotates the load box.

[0024] The first sliding member may be a hook rotatably attached to the vehicle body frame of the vehicle body. The second sliding member may be a roller attached to a frame extending downward from the load box. The biasing member may be a spring that biases the hook toward the locked position.

[0025] The load box may include a load box body and a tailgate rotatably attached to the rear portion of the load box body by a hinge. The locking mechanism may include a lever rotatably attached to a frame extending downward from the load box, a hook that locks the load box body and the tailgate, and a connecting mechanism that connects the lever and the hook in an interlocking manner. The first sliding member may be a roller attached to the lever. The second sliding member may be a guide member attached to the vehicle body frame of the vehicle body. The biasing member may be a spring that biases the lever, the connecting mechanism, or the hook in a direction to release the locking between the load box body and the tailgate.

Effects of the Invention

[0026] According to the present invention, in a dump truck equipped with a sliding automatic locking mechanism capable of measuring the loading weight based on the load in the loading box and automatically locking and unlocking the loading box as it rotates, accurate measurement of the loading weight can be assisted.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Embodiments for Carrying Out the Invention

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a dump truck 1 according to this embodiment.

[0029] The dump truck 1 includes a chassis frame 2, a cab (driver's cab) 3 supported by the chassis frame 2, front wheels 5 and rear wheels 6 supported by the chassis frame 2, a sub-frame 7 disposed behind the cab 3 and on the chassis frame 2, and a cargo box 30 supported by the sub-frame 7. Further, the dump truck 1 includes an engine 9 as a drive source for generating power and a power take-off device (hereinafter referred to as PTO) 10. In this embodiment, the chassis frame 2, the cab 3, the sub-frame 7, the engine 9, and the PTO 10 constitute a vehicle body 1A. A driver's seat (not shown) is provided inside the cab 3. In the following description, unless otherwise specified, front, rear, left, right, up, and down mean front, rear, left, right, up, and down as seen by the driver sitting in the above-mentioned driver's seat.

[0030] The cargo box 30 is rotatably connected to the rear part of the vehicle body 1A. The cargo box 30 is rotatable between a horizontal position and an inclined position. Here, the rear part of the cargo box 30 is rotatably connected to the rear end part of the sub-frame 7 by a hinge shaft 8 extending in the vehicle width direction. FIG. 1 shows the dump truck 1 when the cargo box 30 is in the horizontal position. FIG. 2 is a side view of the dump truck 1 when the cargo box 30 is in the inclined position. The dump truck 1 is provided with a hydraulic cylinder 25 as an actuator for rotating the cargo box 30. The hydraulic cylinder 25 is connected to a dump mechanism 26 connected to the vehicle body 1A and the cargo box 30. The hydraulic cylinder 25 rotates the cargo box 30 via the dump mechanism 26.

[0031] As shown in FIG. 3, the dump truck 1 is provided with a hydraulic circuit 20 in which the hydraulic cylinder 25 is incorporated. The hydraulic circuit 20 has, in addition to the hydraulic cylinder 25, an oil tank 21, a hydraulic pump 22, and a switching valve (not shown). The PTO 10 extracts the power of the engine 9 and transmits the power to the hydraulic pump 22. In the hydraulic circuit 20, by appropriately switching the switching valve, the oil pressurized by the hydraulic pump 22 is supplied to the hydraulic cylinder 25. Thereby, the hydraulic cylinder 25 is driven and the cargo box 30 rotates around the hinge shaft 8 (see FIG. 2).

[0032] As shown in FIG. 1, the cargo box 30 has a bottom plate 31, a front wall 32 standing up from the front end part of the bottom plate 31, a left wall 33 standing up from the left end part of the bottom plate 31, a right wall (not shown) standing up from the right end part of the bottom plate 31, and a tailgate 35 forming the rear wall of the cargo box 30. The bottom plate 31, the front wall 32, the left wall 33, and the right wall constitute the cargo box body 30A.

[0033] The tailgate 35 is configured to be rotatable about a hinge shaft 37 extending in the left - right direction. The tailgate 35 is rotatably attached to the rear part of the load box body 30A by the hinge shaft 37. The tailgate 35 is rotatable between a closed position where it stands up from the rear end of the bottom plate 31 and an open position inclined with respect to the closed position. In FIG. 2, the state when the tailgate 35 is in the closed position is represented by a virtual line, and the state when it is in the open position is represented by a solid line. When the tailgate 35 is in the closed position, the rear of the load box 30 is closed by the tailgate 35. When the tailgate 35 is in the open position, the load box 30 is opened rearward. When discharging earth and sand etc. from the load box 30, the load box 30 is inclined and the tailgate 35 rotates to the open position. Thereby, the load box 30 is opened rearward, and earth and sand etc. can be smoothly discharged from the load box 30.

[0034] The dump truck 1 is provided with an automatic locking mechanism 50 (see FIGS. 4 - 6) that locks the entire load box 30 to the vehicle body 1A when the load box 30 is in the horizontal position. As shown in FIG. 4, a support member 7A is fixed to the sub - frame 7 of the vehicle body 1A. A main girder 38 is fixed to the bottom plate 31 of the load box 30. The main girder 38 extends in the front - rear direction and extends downward from the bottom plate 31 of the load box 30. The automatic locking mechanism 50 includes a hook 51 rotatably attached to the support member 7A, a roller 52 rotatably attached to a support member 38A fixed to the main girder 38, and a spring 53 that biases the hook 51. Here, the spring 53 is constituted by a torsion spring, but the type of the spring 53 is not particularly limited. The hook 51 is rotatable about a rotation center 51c. FIG. 4 shows the state where the hook 51 is in the locked position. The spring 53 biases the hook 51 toward the locked position.

[0035] The roller 52 is configured to roll on the left side surface of the hook 51. The left side surface of the hook 51 has a downward inclined surface 51a extending leftward and upward, and an upward inclined surface 51b extending rightward and upward. The downward inclined surface 51a and the upward inclined surface 51b are continuous. Since the downward inclined surface 51a of the hook 51 extends leftward and upward, when the roller 52 is in contact with the downward inclined surface 51a, the roller 52 receives a leftward force and a downward force from the hook 51. When the load box 30 is in the horizontal position, the roller 52 is in contact with the downward inclined surface 51a of the hook 51. When the load box 30 is in the horizontal position, the load box 30 receives a downward force, and is locked to the vehicle body 1A by this force.

[0036] When the hydraulic cylinder 25 rotates the load box 30 from the horizontal position, the roller 52 rises together with the main girder 38, and pushes up the hook 51 with a force greater than the biasing force of the spring 53. As shown in FIG. 5, since the downward inclined surface 51a of the hook 51 extends leftward and upward, the roller 52 rotates the hook 51 clockwise in FIG. 5 while rolling on the downward inclined surface 51a. Since the upward inclined surface 51b of the hook 51 extends rightward and upward, when the roller 52 moves from the downward inclined surface 51a to the upward inclined surface 51b, the roller 52 receives an upward force from the hook 51. Since the downward force on the load box 30 disappears, the lock of the load box 30 is released. In the present embodiment, the position of the hook 51 when the downward force on the load box 30 by the automatic locking mechanism 50 becomes zero is referred to as the unlocking position. Here, the position of the hook 51 when the roller 52 is in contact with the boundary portion between the downward inclined surface 51a and the upward inclined surface 51b is the unlocking position.

[0037] When the hydraulic cylinder 25 further rotates the load box 30, the roller 52 further rises while rolling on the upward inclined surface 51b of the hook 51, and eventually the roller 52 separates from the hook 51 (see FIG. 6).

[0038] When the hydraulic cylinder 25 rotates the loading box 30 from the inclined position to the horizontal position, the operation reverse to the above-described operation is performed. That is, the roller 52 contacts the upward inclined surface 51b of the hook 51, and the roller 52 rotates the hook 51 clockwise. When the roller 52 moves from the upward inclined surface 51b to the downward inclined surface 51a, the hook 51 rotates counterclockwise by the biasing force of the spring 53. Then, when the loading box 30 reaches the horizontal position, the roller 52 is pushed downward by the downward inclined surface 51a of the hook 51, and the loading box 30 is locked with respect to the vehicle body 1A.

[0039] As described above, the automatic locking mechanism 50 is configured to automatically lock and unlock the loading box 30 as the loading box 30 rotates. The automatic locking mechanism 50 does not include a dedicated drive device for locking and unlocking the loading box 30. When the loading box 30 rotates from the horizontal position toward the inclined position, the automatic locking mechanism 50 is configured to unlock the loading box 30 by moving the hook 51 from the locked position to the unlocked position while sliding with respect to the roller 52. Further, when the loading box 30 rotates toward the horizontal position, the automatic locking mechanism 50 is configured to lock the loading box 30 by moving the hook 51 from the unlocked position to the locked position while sliding with respect to the roller 52.

[0040] Further, the dump truck 1 includes an automatic locking mechanism 60 (see FIGS. 7 to 11) that locks the tailgate 35 in the closed position when the loading box 30 is in the horizontal position. The automatic locking mechanism 60 is an example of an automatic locking mechanism that locks a part of the loading box 30 with respect to another part.

[0041] As shown in FIG. 7, the tailgate 35 is provided with a locking pin 35A extending in the vehicle width direction. The tailgate 35 is rotatable about the upper end portion of the tailgate 35 (see FIG. 2), and the locking pin 35A is provided at the lower end portion of the tailgate 35. The automatic locking mechanism 60 includes a fixed hook 66 fixed to the load box 30, a movable hook 67 that sandwiches the locking pin 35A together with the fixed hook 66, and a connecting rod 68A connected to the movable hook 67. The movable hook 67 is rotatably attached to the fixed hook 66 by a shaft 28 extending in the vehicle width direction. Further, the movable hook 67 is rotatably connected to the connecting rod 68A by a shaft 29 extending in the vehicle width direction. When the connecting rod 68A is pulled forward, the movable hook 67 rotates clockwise about the shaft 28, and the locking pin 35A of the load box 30 is sandwiched by the movable hook 67 and the fixed hook 66. Thereby, the tailgate 35 is locked in the closed position. On the other hand, when the connecting rod 68A is pushed backward, as shown in FIG. 8, the movable hook 67 rotates counterclockwise about the shaft 28. Thereby, the locking pin 35A can move backward, and the tailgate 35 can move from the closed position to the open position (see the solid line in FIG. 2).

[0042] FIG. 9 is a plan view of the automatic locking mechanism 60. The automatic locking mechanism 60 further includes a connecting lever 69 connected to a connecting rod 68A, a connecting rod 68B connected to the connecting lever 69, a spring cylinder 64 connected to the connecting rod 68B, and a return spring 65 that pulls the spring cylinder 64 to the left. The connecting lever 69 is rotatably attached to the loading box body 30A in the left-right direction. The connecting rod 68A is connected to the connecting lever 69 so as to be movable back and forth as the connecting lever 69 rotates, and the connecting rod 68B is connected to the connecting lever 69 so as to be movable left and right as the connecting lever 69 rotates. The spring cylinder 64 has cylinder portions 64A and 64B and a spring (not shown) disposed inside the cylinder portion 64A. The connecting rod 68B is slidably inserted into the cylinder portions 64A and 64B. The spring is connected to the cylinder portion 64A and the connecting rod 68B. The cylinder portion 64A is fixed to the connecting rod 68C. The return spring 65 is a member that biases the movable hook 67 in the opening direction, and its mounting position is not particularly limited. Here, one end of the return spring 65 is attached to the cylinder portion 64A, and the other end of the return spring 65 is attached to the loading box body 30A.

[0043] FIG. 10 is a front view of a part of the automatic locking mechanism 60. The automatic locking mechanism 60 further includes a connecting rod 68C, a lever 63 connected to the connecting rod 68C, a roller 61 rotatably attached to the tip of the lever 63, and a guide member 62 fixed to the sub-frame 7. The connecting rod 68C is fixed to the cylinder portion 64A of the spring cylinder 64. The lever 63 is rotatably connected to the connecting rod 68C. A support member 38B is fixed to the main girder 38 extending downward from the loading box 30. The lever 63 is rotatably attached to the support member 38B by a rotation shaft 63A. The lever 63 is rotatable around the rotation shaft 63A.

[0044] The roller 61 is configured to roll on the left side surface of the guide member 62. The left side surface of the guide member 62 has a vertically extending vertical surface 62a and an inclined surface 62b extending rightward and upward. The inclined surface 62b is formed above the vertical surface 62a, and the inclined surface 62b and the vertical surface 62a are continuous.

[0045] As shown in FIG. 10, when the load box 30 is in the horizontal position, the roller 61 is in contact with the vertical surface 62a of the guide member 62. The lower end of the lever 63 is pushed leftward by the guide member 62, and the upper end of the lever 63 pulls the connecting rod 68C rightward. When the connecting rod 68C is pulled rightward, the connecting rod 68B is also pulled rightward, so that the connecting rod 68A is pulled forward via the lever 69. Therefore, the lock pin 35A of the tailgate 35 is sandwiched between the movable hook 67 and the fixed hook 66 (see FIG. 7). Accordingly, when the load box 30 is in the horizontal position, the tailgate 35 is locked in the closed position.

[0046] When the hydraulic cylinder 25 rotates the load box 30 from the horizontal position, the roller 61 rises while rolling on the vertical surface 62a. When the roller 61 moves from the vertical surface 62a to the inclined surface 62b, the lever 63 rotates in the clockwise direction in FIG. 10 about the rotation axis 63A. Then, the upper end of the lever 63 moves leftward, and the connecting rod 68C moves leftward. When the connecting rod 68C moves leftward, the connecting rod 68B also moves leftward, so that the connecting rod 68A is pushed rearward via the lever 69. As a result, the movable hook 67 rotates counterclockwise in FIG. 8 about the shaft 28, and the lock pin 35A becomes movable rearward. Accordingly, the lock of the tailgate 35 is released.

[0047] When the hydraulic cylinder 25 further rotates the load box 30, the roller 61 further rises while rolling on the inclined surface 62b of the guide member 62 and eventually separates from the guide member 62 (see FIG. 11). Here, the position where the roller 61 separates from the guide member 62 is the unlock position.

[0048] When the hydraulic cylinder 25 rotates the loading box 30 from the inclined position to the horizontal position, the operation reverse to the above-described operation is performed. That is, the roller 61 comes into contact with the inclined surface 62b of the guide member 62, and the roller 61 moves leftward and downward along the inclined surface 62b. As a result, the lever 63 rotates counterclockwise in FIG. 11 about the rotation axis 63A, and the connecting rod 68C is pulled rightward. Then, the connecting rod 68B is also pulled rightward, and the connecting rod 68A is pulled forward via the lever 69. As a result, the movable hook 67 rotates clockwise in FIG. 8 about the shaft 28, and the lock pin 35A of the tailgate 35 is sandwiched between the movable hook 67 and the fixed hook 66 (see FIG. 7). Thereby, the tailgate 35 is locked.

[0049] Thus, the automatic locking mechanism 60 is configured to automatically lock and unlock the tailgate 35 as the loading box 30 rotates. The automatic locking mechanism 60 does not include a dedicated drive device for locking and unlocking the tailgate 35. When the loading box 30 rotates from the horizontal position toward the inclined position, the automatic locking mechanism 60 is configured to unlock the tailgate 35 by moving the roller 61 from the locked position to the unlocked position while sliding with respect to the guide member 62. Further, when the loading box 30 rotates toward the horizontal position, the automatic locking mechanism 60 is configured to lock the tailgate 35 by moving the roller 61 from the unlocked position to the locked position while sliding with respect to the guide member 62.

[0050] As shown in FIG. 1, the vehicle body 1A has a seating portion 11 that supports the bottom of the load box 30. The seating portion 11 is provided on the sub-frame 7. When the load box 30 is in the horizontal position as shown in FIG. 1, the bottom of the load box 30 is supported by the seating portion 11. On the other hand, as shown in FIG. 12, when the load box 30 is rotated around the hinge shaft 8 by driving the hydraulic cylinder 25, the bottom of the load box 30 separates from the seating portion 11. At this time, the load of the load box 30 is applied to the hydraulic cylinder 25. The greater the loading weight of the load box 30, the greater the load applied to the hydraulic cylinder 25. The greater the load applied to the hydraulic cylinder 25, the greater the hydraulic pressure value of the hydraulic cylinder 25. Therefore, based on the hydraulic pressure value of the hydraulic cylinder 25, the loading weight of the load box 30 can be calculated. The hydraulic cylinder 25 is an example of a pressure-receiving device that receives the load of the load box 30. In the dump truck 1, a measurer such as a driver operates the hydraulic cylinder 25 to slightly incline the load box 30 and measures the loading weight of the load box 30.

[0051] In addition, when a load is loaded on the load box 30, the weight obtained by adding the weight of the load box 30 itself and the weight of the load is the weight of the load box 30. However, the weight of the load box 30 itself is specified in advance. By subtracting the weight of the load box 30 itself from the weight of the load box 30, the weight of the load can be calculated. Measuring the weight of the load box 30 with a load loaded thereon and measuring the loading weight of the load box 30 are technically equivalent matters. In this specification, the measurement of the loading weight shall include measuring the loading weight itself and measuring a weight having a correlation with the loading weight (in the above example, the weight of the load box 30 with a load loaded thereon). In other words, the measurement of the loading weight includes the measurement of any weight that can identify the loading weight.

[0052] As shown in FIG. 13, the dump truck 1 includes a hydraulic sensor 71 that detects the hydraulic pressure value of the hydraulic cylinder 25, an inclination angle detection device 75 that detects the inclination angle of the loading box 30 (hereinafter, also simply referred to as the inclination angle), a weight measurement device 70 that calculates the loading weight of the loading box 30 based on the hydraulic pressure value detected by the hydraulic sensor 71, a weight display device 73 that displays the weight calculated by the weight measurement device 70, and a notification device 72. Note that the inclination angle of the loading box 30 is the inclination angle from the horizontal position of the loading box 30. The weight measurement device 70 is configured by a microcomputer having a processor and a memory. In the memory, the relationship between the loading weight of the loading box 30 and the hydraulic pressure value of the hydraulic cylinder 25 is stored in advance. The processor refers to the above relationship stored in the memory and calculates the loading weight of the loading box 30 from the hydraulic pressure value detected by the hydraulic sensor 71.

[0053] In the present embodiment, the weight display device 73 is installed at the upper part of the front wall 32 of the loading box 30 (see FIG. 1). The weight display device 73 is installed backward so that an operator or the like can visually recognize it from the rear of the dump truck 1. However, the position and form of the weight display device 73 are not limited in any way. For example, the weight display device 73 may be arranged inside the cab 3. The loading weight calculated by the weight measurement device 70 is displayed on the weight display device 73.

[0054] Incidentally, when the loading box 30 is in an inclined state, the load of the loading box 30 is supported by the hydraulic cylinder 25 and the hinge shaft 8. When the inclination angle of the loading box 30 is small, the load received by the hinge shaft 8 is relatively small, and the load received by the hydraulic cylinder 25 is relatively large. Therefore, the loading load (hereinafter, also simply referred to as the loading weight) of the loading box 30 can be calculated based on the hydraulic pressure value of the hydraulic cylinder 25. On the other hand, when the inclination angle of the loading box 30 is large, the load received by the hinge shaft 8 becomes relatively large, and the load received by the hydraulic cylinder 25 becomes relatively small. The larger the inclination angle, the smaller the hydraulic pressure value of the hydraulic cylinder 25. Therefore, the loading weight calculated based on the hydraulic pressure value of the hydraulic cylinder 25 tends to be smaller than the actual loading weight as the inclination angle increases. As the inclination angle increases, the load borne by the hydraulic cylinder 25 decreases and the hydraulic pressure drops. When the hydraulic pressure drops, the ratio of the load conversion value to the change in hydraulic pressure becomes large (the load per 1 Mpa of error becomes large), making it difficult to measure accurately. Also, in reality, due to the properties of the load, the load in the loading box 30 shifts backward, so the center of gravity position shifts and accurate measurement becomes impossible.

[0055] The broken line in FIG. 14 schematically shows the relationship between the inclination angle of the loading box 30 and the hydraulic pressure value of the hydraulic cylinder 25 when the automatic locking mechanisms 50 and 60 are not present. θ represents the inclination angle of the loading box 30, and P represents the hydraulic pressure value of the hydraulic cylinder 25. As described above, the larger the inclination angle, the smaller the hydraulic pressure value. As described above, the measurement of the loading weight is performed after the measurer slightly inclines the loading box 30 by operating the hydraulic cylinder 25. The inclination angle of the loading box 30 when measuring the loading weight varies depending on the operation of the measurer. In the present embodiment, in order to measure the loading weight more accurately, an upper limit angle θmax is set in advance for the inclination angle at the time of measurement. The notification device 72 is configured to notify the measurer when the inclination angle at the time of measuring the loading weight is larger than the predetermined upper limit angle θmax.

[0056] Note that the notification method of the notification device 72 is not limited in any way. The notification method of the notification device 72 may be, for example, to display a message or the like on the display screen, or to output sound from the speaker. The notification device 72 may be a device that performs notification by light, image, sound, or the like, and may be, for example, an LED lamp, a liquid crystal display device, a speaker, or the like.

[0057] As described above, the dump truck 1 according to the present embodiment includes automatic locking mechanisms 50 and 60 that lock the loading box 30 when the loading box 30 is in the horizontal position. Note that locking the loading box 30 includes locking the entire loading box 30 to the vehicle body 1A and locking a part of the loading box 30 to another part. The automatic locking mechanism 50 is a mechanism that locks the entire loading box 30 to the vehicle body 1A. The automatic locking mechanism 60 is a mechanism that locks the tailgate 35, which is a part of the loading box 30, to the loading box body 30A, which is another part of the loading box 30.

[0058] As described above, in the automatic locking mechanism 50 (see FIG. 4), when the loading box 30 rotates from the horizontal position toward the inclined position, the roller 52 receives a force from the hook 51 until the roller 52 separates from the hook 51. When the roller 52 is in contact with the downward inclined surface 51a of the hook 51, the roller 52 receives a downward force from the hook 51. The hydraulic cylinder 25 receives the downward load by the hook 51 in addition to the load of the loading box 30. Therefore, the load received by the hydraulic cylinder 25 is a load larger than the loading weight of the loading box 30. On the other hand, when the roller 52 is in contact with the upward inclined surface 51b of the hook 51, the roller 52 receives an upward force from the hook 51. The hydraulic cylinder 25 receives the upward load by the hook 51. Therefore, the load received by the hydraulic cylinder 25 is a load smaller than the loading weight of the loading box 30. Thus, the hydraulic cylinder 25 receives not only the load of the loading box 30 but also the load by the automatic locking mechanism 50.

[0059] When the loading box 30 rotates from the horizontal position toward the inclined position, the roller 61 moves while being pressed against the guide member 62 until the roller 61 separates from the guide member 62. When the roller 61 is in contact with the guide member 62, the hydraulic cylinder 25 receives not only the load of the loading box 30 but also the load by the automatic locking mechanism 60.

[0060] Thus, when the inclination angle is relatively small, the hydraulic cylinder 25 receives not only the load of the loading box 30 but also the loads by the automatic locking mechanisms 50 and 60. The solid line in FIG. 14 is a graph schematically showing the relationship between the inclination angle of the loading box 30 and the hydraulic pressure value of the hydraulic cylinder 25 in the dump truck 1 equipped with the automatic locking mechanisms 50 and 60 (that is, the dump truck 1 according to the present embodiment). In the present embodiment, due to the influence of the automatic locking mechanisms 50 and 60, when the inclination angle is θ1 or less, the hydraulic pressure value becomes larger than the original hydraulic pressure value, and when the inclination angle is larger than θ1 and less than θ2, the hydraulic pressure value becomes smaller than the original hydraulic pressure value. Note that the original hydraulic pressure value is the hydraulic pressure value when the automatic locking mechanisms 50 and 60 are not provided (see the broken line in FIG. 14).

[0061] Here, θ2 is the minimum value among the inclination angles at which the hydraulic pressure value of the hydraulic cylinder 25 is not affected by the automatic locking mechanisms 50 and 60. When the inclination angle is θ2 or more, the roller 52 of the automatic locking mechanism 50 separates from the hook 51, and the roller 61 of the automatic locking mechanism 60 separates from the guide member 62.

[0062] In the dump truck 1, a predetermined angle smaller than the upper limit angle θmax is set as the lower limit angle θmin in advance, and the notification device 72 issues a notification if the tilt angle of the cargo box 30 when measuring the load weight is less than the lower limit angle θmin. The lower limit angle θmin can be set as appropriate, but it is preferable that the automatic locking mechanisms 50, 60 have little effect when the tilt angle is equal to or greater than the lower limit angle θmin. In this embodiment, the lower limit angle θmin is set to θ2. That is, the lower limit angle θmin is set to the smallest tilt angle at which the hydraulic pressure value of the hydraulic cylinder 25 is not affected by the automatic locking mechanisms 50, 60. The difference between the upper limit angle θmax and the lower limit angle θmin is not particularly limited, but is set to 1° or less in this embodiment. The values of the upper limit angle θmax and the lower limit angle θmin are not particularly limited, but may be, for example, θmax = 3° to 4° or θmin = 2.5° to 3.5°. In this embodiment, θmax = 3.5° and θmin = 3°.

[0063] As described above, in the dump truck 1 according to this embodiment, if the tilt angle of the loading container 30 is small, the hydraulic pressure of the hydraulic cylinder 25 is affected by the automatic locking mechanisms 50 and 60, which may result in an inaccurate measurement of the load weight. However, if the tilt angle of the loading container 30 when measuring the load weight is less than the lower limit angle θmin, a notification is issued by the notification device 72. The measurer is then notified that the load weight may not be measured accurately. This notification prompts the measurer to increase the tilt angle of the loading container 30 to accurately measure the load weight. By receiving this notification, the measurer can change the tilt angle of the loading container 30 to a value equal to or greater than the lower limit angle θmin, enabling a more accurate measurement of the load weight.

[0064] In this embodiment, the lower limit angle θmin is set to θ2, which is the smallest tilt angle at which the hydraulic pressure of the hydraulic cylinder 25 is not affected by the automatic locking mechanisms 50, 60. When the tilt angle is equal to or greater than the lower limit angle θmin, the roller 52 of the automatic locking mechanism 50 is separated from the hook 51, and the roller 61 of the automatic locking mechanism 60 is separated from the guide member 62. Therefore, by setting the tilt angle of the shipping box 30 when measuring the load weight to be equal to or greater than the lower limit angle θmin, the load weight can be measured more accurately.

[0065] Furthermore, according to this embodiment, if the tilt angle of the packing box 30 when measuring the load weight is greater than the upper limit angle θmax, a notification is issued by the notification device 72. By receiving this notification, the measurer can recognize that the measurement accuracy of the load weight may be low. Therefore, the measurer is prompted to reduce the tilt angle of the packing box 30 in order to measure the load weight more accurately. By receiving this notification, the measurer can change the tilt angle of the packing box 30 to less than the upper limit angle θmax, thereby enabling the load weight to be measured more accurately.

[0066] The effect of the automatic locking mechanisms 50, 60 on the hydraulic pressure of the hydraulic cylinder 25 can be determined in advance through simulations, tests, or the like. For example, the relationship between the tilt angle and the hydraulic pressure, shown by the solid line in FIG. 14, can be determined in advance. Therefore, the weight measuring device 70 may store the hydraulic pressure value ΔP due to the automatic locking mechanisms 50, 60 for each tilt angle in advance and add the hydraulic pressure value ΔP as a correction value to the hydraulic pressure value P detected by the hydraulic pressure sensor 71. The correction value ΔP (i.e., the hydraulic pressure value due to the automatic locking mechanisms 50, 60) corresponds to the difference between the hydraulic pressure value when the automatic locking mechanisms 50, 60 are not present and the hydraulic pressure value when the automatic locking mechanisms 50, 60 are present. The correction value ΔP can be positive or negative. Calculating the load weight based on the corrected hydraulic pressure value P + ΔP in this way makes it possible to accurately measure the load weight even when the tilt angle of the cargo box 30 is less than the lower limit angle θmin.

[0067] It is also possible to calculate the load weight by determining a weight correction value ΔW in advance for each tilt angle of the container 30 and adding the correction value ΔW to the load weight W calculated based on the hydraulic pressure value P detected by the hydraulic pressure sensor 71. Here, the load weight correction value ΔW is technically equivalent to the load weight corresponding to the hydraulic pressure value ΔP caused by the automatic locking mechanisms 50, 60. Therefore, calculating W+ΔW as the corrected load weight is included in calculating the load weight based on the corrected hydraulic pressure value P+ΔP.

[0068] In the dump truck 1, if the tilt angle of the cargo box 30 when measuring the loaded weight is less than the lower limit angle θmin, the notification device 72 may issue a notification, and the weight measuring device 70 may calculate the loaded weight based on the corrected hydraulic pressure value P+ΔP. Alternatively, if the tilt angle of the cargo box 30 when measuring the loaded weight is less than the lower limit angle θmin, the notification device 72 may not issue a notification, and the weight measuring device 70 may calculate the loaded weight based on the corrected hydraulic pressure value P+ΔP. In this case, the notification device 72 may not be required. That is, as another embodiment, the dump truck 1 may not be provided with the notification device 72, and may be configured to calculate the loaded weight based on the corrected hydraulic pressure value P+ΔP when the tilt angle of the cargo box 30 when measuring is less than the lower limit angle θmin.

[0069] Although the exemplary embodiments of the present invention have been described above, the above-described embodiments are merely examples, and various other embodiments are possible.

[0070] In the automatic locking mechanism 50 of the above embodiment (see FIG. 4), roller 52, which is an example of the first sliding member, is supported on cargo box 30, and hook 51, which is an example of the second sliding member, is supported on vehicle body 1A. However, the first sliding member may be supported on vehicle body 1A, and the second sliding member may be supported on cargo box 30. For example, hook 51 may be rotatably attached to main girder 38, and roller 52 may be attached to support member 7A. Spring 53 that biases hook 51 may be provided on the cargo box 30 side.

[0071] In the automatic locking mechanism 50 (see FIG. 4) of the above embodiment, the hook 51, which is an example of the second sliding member, has a curved surface inclined with respect to the horizontal plane and the vertical plane, and the first sliding member has a roller 52 that rolls on the above curved surface. However, the first sliding member may have a curved surface inclined with respect to the horizontal plane and the vertical plane, and the second sliding member may have a roller that rolls on the above curved surface.

[0072] In the automatic locking mechanism 60 (see FIG. 10) of the above embodiment, the roller 61, which is an example of the first sliding member, is supported by the load box 30, and the guide member 62, which is an example of the second sliding member, is supported by the vehicle body 1A. However, the first sliding member may be supported by the vehicle body 1A, and the second sliding member may be supported by the load box 30. The biasing member may be provided on the vehicle body 1A side.

[0073] In the automatic locking mechanism 60 (see FIG. 10) of the above embodiment, the guide member 62, which is an example of the second sliding member, has a curved surface inclined with respect to the horizontal plane and the vertical plane, and the first sliding member has a roller 61 that rolls on the above curved surface. However, the first sliding member may have a curved surface inclined with respect to the horizontal plane and the vertical plane, and the second sliding member may have a roller that rolls on the above curved surface.

[0074] The mounting position of the automatic locking mechanism 50 may be at the lower part of the front wall 32 of the load box 30. The biasing direction (moving direction) of the hook 51 may be the front-rear direction. The automatic locking mechanism 50 only needs to be a mechanism that restrains the load box 30 downward in the traveling posture, and its configuration is not limited.

[0075] The automatic locking mechanisms 50 and 60 according to the above embodiment are merely examples. The dump truck 1 may be provided with a locking mechanism having other configurations.

[0076] The pressure receiving device that receives the load of the load box 30 is not limited to the hydraulic cylinder 25. The pressure receiving device may be used in combination with an actuator that rotates the load box 30, or may be separate from the actuator that rotates the load box 30.

[0077] In the above-described embodiment, an example in which an operator operates to tilt the loading box 30 when measuring the loading weight has been described. However, by adopting a configuration further including a loading box tilting unit 100 shown in FIG. 15, the tilting of the loading box 30 and the measurement of the loading weight can be automatically performed.

[0078] The loading box tilting unit 100 includes a control unit 101, a weight measurement button 102, an electric motor 110 that is driven by receiving power supply, a hydraulic pump 122 that is driven by the electric motor 110, a solenoid valve 123, and a loading box tilting cylinder 125. The solenoid valve 123 is switched based on a switching signal transmitted from the control unit 101, and controls the hydraulic oil supplied to the loading box tilting cylinder 125. The cylinder tube of the loading box tilting cylinder 125 is connected to the sub-frame 7, and the rod of the loading box tilting cylinder 125 is detachably attached to the lower part of the front wall 32. The rod of the loading box tilting cylinder 125 may support the loading box 30 so as to be separable from below. The loading box tilting cylinder 125 extends by being supplied with the hydraulic oil discharged from the hydraulic pump 122, and tilts the loading box 30 backward about the hinge shaft 8. The hydraulic pressure sensor 171 detects the hydraulic pressure of the loading box tilting cylinder 125, and outputs the detection result to the control unit 101.

[0079] In the configuration of FIG. 15, when measuring the loading weight, the operator operates the weight measurement button 102. A measurement signal from the weight measurement button 102 is input to the control unit 101. When the control unit 101 refers to the tilt angle input from the tilt angle detection device 75 and determines that the loading box 30 is not in the horizontal position, the control unit 101 outputs a switching signal to the solenoid valve 23 so as to contract the hydraulic cylinder 25 by the own weight of the loading box 30. At this time, in the hydraulic cylinder 25, the bottom side port and the rod side port are in an open state to the atmosphere, and the loading box 30 can be tilted by the loading box tilting cylinder 125.

[0080] When the control unit 101 determines that the cargo box 30 is in a horizontal state, it outputs a drive signal to the electric motor 110 to drive it, and at the same time outputs a switching signal to the solenoid valve 123 so that the hydraulic oil is supplied to the cargo box tilting cylinder 125. When the cargo box tilting cylinder 125 extends and the cargo box 30 tilts, the control unit 101 refers to the tilting angle of the tilting angle detection device 75. When it determines that the tilting angle of the cargo box 30 has reached the lower limit angle θmin, it stops driving the electric motor 110 to hold the tilting state of the cargo box 30. The control unit 101 outputs a measurement signal to the weight measuring device 70 in the state where the cargo box 30 is at the lower limit angle θmin, so that the weight measuring device 70 calculates the loaded weight based on the detected value of the hydraulic pressure sensor 171.

[0081] When the calculation of the loaded weight is completed, the control unit 101 outputs a switching signal to the solenoid valve 123 to return the hydraulic oil on the bottom side of the cargo box tilting cylinder 125 to the tank 21, thereby reducing the cargo box tilting cylinder 125. When the control unit 101 determines that the cargo box 30 is in the horizontal position with reference to the tilting angle of the tilting angle detection device 75, it ends the measurement by the weight measurement button 102.

[0082] In addition, in the configuration of FIG. 15, a separate measurement end button may be provided. In this case, after the calculation of the loaded weight by the weight measuring device 70 is completed, by operating the measurement end button, the cargo box tilting cylinder 125 contracts and the cargo box 30 moves to the horizontal position. Also, in FIG. 15, the configuration may be such that the weight measurement button 102 is not provided. In this configuration, when the control unit 101 receives a measurement start signal transmitted from a chassis side control unit (not shown), a series of lifting operations and weight measurement of the cargo box 30 are automatically performed. When the control unit 101 determines that the cargo box 30 has become horizontal after the weight measurement is completed, it outputs a measurement end signal to the chassis side control unit.

[0083] With the configuration shown in FIG. 16, the inclination of the load box 30 and the measurement of the loading weight can also be automatically performed. When a measurement signal is input from the weight measurement button 102, the control unit 201 outputs a switching signal to the solenoid valve 23 to supply hydraulic oil to the hydraulic cylinder 25, causing it to extend. When the hydraulic cylinder 25 extends and the load box 30 inclines, the control unit 201 refers to the inclination angle of the inclination angle detection device 75. When it determines that the inclination angle of the load box 30 has reached the lower limit angle θmin, it outputs a switching signal to the solenoid valve 23 to stop the supply of hydraulic oil to the hydraulic cylinder 25 and holds the inclined state of the load box 30. The control unit 201 outputs a measurement signal to the weight measurement device 70 in the state where the load box 30 is at the lower limit angle θmin, and the weight measurement device 70 calculates the loading weight based on the detected value of the hydraulic pressure sensor 71.

[0084] When the calculation of the loading weight is completed, the control unit 201 outputs a switching signal to the solenoid valve 23 to return the hydraulic oil on the bottom side of the hydraulic cylinder 25 to the tank 21, thereby contracting the hydraulic cylinder 25 and rotating the load box 30 toward the horizontal position. When the control unit 201 determines that the load box 30 has reached the horizontal position by referring to the inclination angle of the inclination angle detection device 75, it ends the measurement by the weight measurement button 102.

[0085] Furthermore, with the configuration shown in FIG. 17, the inclination of the load box 30 and the measurement of the loading weight can also be automatically performed. When a measurement signal is input from the weight measurement button 102, the control unit 301 outputs switching signals to the solenoid valves 324, 325, and 326 to switch so that the hydraulic oil discharged from the hydraulic pump 122 is supplied to the bottom side port of the hydraulic cylinder 25. In that state, by driving the electric motor 110, the hydraulic cylinder 25 is extended. When the control unit 301 refers to the inclination angle of the inclination angle detection device 75 and determines that the inclination angle of the load box 30 has reached the lower limit angle θmin, it outputs switching signals to the solenoid valves 324, 325, and 326 to stop the supply of hydraulic oil to the hydraulic cylinder 25 and holds the inclined state of the load box 30. The control unit 301 calculates the loading weight by outputting a measurement signal to the weight measurement device 70 in the state where the load box 30 is at the lower limit angle θmin.

[0086] When the calculation of the loading weight is completed, the control unit 301 outputs a switching signal to the solenoid valves 324, 325, and 326 to return the hydraulic oil on the bottom side of the hydraulic cylinder 25 to the tank 21, thereby rotating the loading box 30 toward the horizontal position. When the control unit 301 determines that the loading box 30 has reached the horizontal position with reference to the inclination angle of the inclination angle detection device 75, it ends the measurement by the weight measurement button 102. When discharging the load by tilting the loading box 30, the control unit 301 outputs a switching signal to the solenoid valves 323, 324, and 325, and switches so that the hydraulic oil discharged from the hydraulic pump 22 is supplied to the bottom side port of the hydraulic cylinder 25. By driving the PTO 10 in that state, the hydraulic cylinder 25 is extended by the hydraulic oil from the hydraulic pump 22 to tilt the loading box 30.

[0087] Although the weighing accuracy is improved by the present invention, the accuracy is further improved by considering vehicle inclination (roll, pitch).

Explanation of Signs

[0088] [[ID=LL]]1 Dump truck 1A Vehicle body 7 Sub-frame (vehicle body frame) 25 Hydraulic cylinder (pressure receiving device) 30 Loading box 35 Tailgate 50 Locking device 51 Hook (second sliding member) 52 Roller (first sliding member) 53 Spring (biasing member) 60 Locking device 61 Roller (first sliding member) 62 Guide member (second sliding member) ) 65 Return spring (biasing member) 70 Weight measuring device 72 Notification device

Claims

1. A vehicle body, a loading box rotatably connected to the rear of the vehicle body and rotatable between a horizontal position and an inclined position, a pressure-receiving device connected to the loading box and receiving the load of the loading box, a weight measuring device for measuring the loading weight of the loading box based on the load of the loading box received by the pressure-receiving device when the loading box is inclined, a locking mechanism for locking the loading box when the loading box is in the horizontal position, a notification device for performing a notification when the inclination angle of the loading box when measuring the loading weight of the loading box is less than a predetermined lower limit angle, A dump truck equipped with the above.

2. The locking mechanism includes, a first sliding member movably supported on one of the vehicle body and the loading box and movable between a locking position and an unlocking position, a biasing member for biasing the first sliding member toward the locking position or the unlocking position, and a second sliding member provided on the other of the vehicle body and the loading box, and when the loading box rotates from the horizontal position toward the inclined position, the first sliding member moves from the locking position to the unlocking position while sliding with respect to the second sliding member, thereby unlocking the loading box, The dump truck according to claim 1, wherein when the loading box rotates toward the horizontal position, the first sliding member moves from the unlocking position to the locking position while sliding with respect to the second sliding member, thereby locking the loading box.

3. The locking mechanism is configured such that the first sliding member is separated from the second sliding member when the inclination angle of the loading box is a predetermined angle or more, The dump truck according to claim 2, wherein the lower limit angle is the predetermined angle.

4. The locking mechanism is configured such that the first sliding member is separated from the second sliding member when the inclination angle of the loading box is a predetermined angle or more, The dump truck according to claim 2, wherein the notification device is further configured to perform a notification when the inclination angle of the loading box when measuring the loading weight of the loading box is greater than a predetermined upper limit angle greater than the predetermined angle.

5. The locking mechanism is configured such that the first sliding member is separated from the second sliding member when the inclination angle of the loading box is a predetermined angle or more, When the inclination angle of the load box is less than the predetermined angle when measuring the loading weight of the load box, the dump truck according to claim 2 is configured to measure the loading weight of the load box based on the load obtained by adding a correction value determined in advance according to the inclination angle of the load box to the load of the load box received by the pressure receiving device.

6. A vehicle body, A load box rotatably connected to the rear part of the vehicle body and rotatable between a horizontal position and an inclined position, A pressure receiving device connected to the load box and receiving the load of the load box, A weight measuring device configured to measure the loading weight of the load box based on the load received by the pressure receiving device when the load box is inclined, A locking mechanism for locking the load box when the load box is in the horizontal position, and comprising: When the inclination angle of the load box is less than a predetermined angle when measuring the loading weight of the load box, the weight measuring device is configured to measure the loading weight of the load box based on the load obtained by adding a correction value determined in advance according to the inclination angle of the load box to the load of the load box received by the pressure receiving device.

7. The locking mechanism includes A first sliding member movably supported on one of the vehicle body and the load box and movable between a locked position and an unlocked position, A biasing member for biasing the first sliding member toward the locked position or the unlocked position, A second sliding member provided on the other of the vehicle body and the load box, and having When the load box rotates from the horizontal position toward the inclined position, the first sliding member slides with respect to the second sliding member and moves from the locked position to the unlocked position, thereby releasing the lock of the load box. When the load box rotates toward the horizontal position, the first sliding member slides with respect to the second sliding member and moves from the unlocked position to the locked position, thereby locking the load box. The dump truck according to claim 6 is configured as such.

8. One of the first sliding member and the second sliding member has a curved surface inclined with respect to a horizontal plane and a vertical plane, The other of the first sliding member and the second sliding member has a roller rolling on the curved surface. The dump truck according to any one of claims 2 to 5 and 7.

9. The pressure receiving device is composed of a hydraulic cylinder for rotating the load box. The dump truck according to any one of claims 1 to 7, wherein the weight measuring device is configured to measure the loading weight of the load box based on the hydraulic pressure value of the hydraulic cylinder.

10. The first sliding member is a hook rotatably attached to the vehicle body frame of the vehicle body. The second sliding member is a roller attached to a frame extending downward from the load box. The dump truck according to any one of claims 2 to 5 and 7, wherein the biasing member is a spring that biases the hook toward the locked position.

11. The load box has a load box body and a tailgate rotatably attached to the rear portion of the load box body by a hinge. The locking mechanism has a lever rotatably attached to a frame extending downward from the load box, a hook that locks the load box body and the tailgate, and a connecting mechanism that connects the lever and the hook in an interlocking manner. The first sliding member is a roller attached to the lever. The second sliding member is a guide member attached to the vehicle body frame of the vehicle body. The dump truck according to any one of claims 2 to 5 and 7, wherein the biasing member is a spring that biases the lever, the connecting mechanism, or the hook in a direction to release the locking between the load box body and the tailgate.

Images