Control device and pallet lock device

Abstract

To reduce a difference between a position of a movable part recognized by a control device and an actual position of the movable part.SOLUTION: A control device includes a processing unit and a storage unit. The processing unit recognizes a position of a movable part from a voltage of a potentiosensor. The potentiosensor detects the position of the movable part by converting a change in the position of the movable part into a voltage. The storage unit stores a voltage difference between a first position voltage which is a voltage when the movable part is in a first position, and a second position voltage which is a voltage when the movable part is in a second position. The processing unit acquires a detection result of a switch that switches between on and off when the movable part is in the first position, and determines the voltage acquired from the potentiosensor when the switch switches between on and off as the first position voltage. The processing unit determines the voltage obtained by adding the voltage difference stored in the storage unit to the first position voltage as the second position voltage.SELECTED DRAWING: Figure 13

Description

Technical Field

[0001] The present disclosure relates to a control device and a pallet locking device.

Background Art

[0002] The industrial vehicle disclosed in Patent Document 1 includes a fork and a pallet locking device. The fork supports a pallet. The pallet locking device locks the pallet supported by the fork. The pallet locking device includes an arm, a connecting rod, a joint, an actuator, a potentiometer, and a control device. The connecting rod is connected to the joint. The connecting rod is interlocked with the actuator. When the connecting rod moves in conjunction with the actuator, the arm is pressed against the pallet. Thereby, the pallet is locked. The potentiometer has a movable part and converts a change in the position of the movable part into a voltage. The position of the movable part changes depending on the pressing force of the arm against the pallet. The control device recognizes the position of the movable part from the voltage of the potentiometer. The control device controls the pallet locking device according to the position of the movable part.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the potentiometer deteriorates, the voltage characteristics of the potentiometer change. Since the correspondence between the movable part and the voltage changes, the control device cannot recognize the correct position of the movable part.

Means for Solving the Problems

[0005] The control device that solves the above problems includes a processing unit that recognizes the position of the movable part by obtaining the voltage from a potentiometer sensor that detects the position of the movable part by converting the change in the position of the movable part into a voltage, and a storage unit that stores the voltage difference between a first position voltage that is the voltage when the movable part is in the first position and a second position voltage that is the voltage when the movable part is in the second position. The processing unit obtains the detection result of a switch that switches between on and off when the movable part is in the first position, and sets the voltage obtained from the potentiometer sensor when the on and off are switched as the first position voltage, and sets the voltage obtained by adding the voltage difference to the first position voltage as the second position voltage.

[0006] In the change of the voltage characteristics of the potentiometer sensor due to the deterioration of the potentiometer sensor, the first position voltage corresponding to the first position and the second position voltage corresponding to the second position change. On the other hand, the voltage difference between the first position voltage and the second position voltage does not change, or the change is slight. Therefore, it is possible to detect with a switch that the movable part has moved to the first position. As a result, since the fact that the movable part is in the first position can be recognized by the switch, the voltage at this time is set as the first position voltage, and the second position voltage can be calculated by adding the voltage difference stored in the storage unit to the first position voltage. Thereby, even if the potentiometer sensor deteriorates, the difference between the position of the movable part recognized by the control device and the actual position of the movable part can be reduced.

[0007] Regarding the above control device, the control device is provided in a pallet locking device that locks a pallet supported by a fork. The pallet locking device includes an actuator, an arm pressed against the pallet, and a link mechanism that interlocks with the actuator and swings the arm. The movable part changes its position by the pressing force of the arm against the pallet. The first position is the position of the movable part in an unlocked state where the pallet is not locked by the arm. The second position includes the position of the movable part in a locked state where the pallet is locked by the arm and the position of the movable part in a state where the pallet is placed on the floor. The voltage difference includes a first voltage difference that is the difference between the voltage in the unlocked state and the voltage in the locked state, and a second voltage difference that is the difference between the voltage in the unlocked state and the voltage in the state where the pallet is placed on the floor.

[0008] The pallet locking device for solving the above problems is a pallet locking device that locks a pallet supported by a fork, and includes an actuator, an arm pressed against the pallet, a link mechanism that interlocks with the actuator and swings the arm, a movable part whose position changes by the pressing force of the arm against the pallet, a potentiometer sensor that detects the position of the movable part by converting the change in the position of the movable part into a voltage, a processing unit that recognizes the position of the movable part by acquiring the voltage from the potentiometer sensor, a storage unit that stores a voltage difference between a first position voltage that is the voltage when the movable part is in a first position and a second position voltage that is the voltage when the movable part is in a second position, and a switch that is switched between on and off by the movement of the link mechanism and is switched between on and off when the movable part is in the first position. The first position is the position of the movable part in an unlocked state where the pallet is not locked by the arm, and the second position includes the position of the movable part in a locked state where the pallet is locked by the arm and the position of the movable part in a storage state where the pallet is placed on the floor. The voltage difference includes a first voltage difference that is the difference between the voltage in the unlocked state and the voltage in the locked state, and a second voltage difference that is the difference between the voltage in the unlocked state and the voltage in the storage state. The processing unit sets the voltage acquired from the potentiometer sensor when the switch is switched between on and off as the first position voltage, sets the voltage obtained by adding the first voltage difference to the first position voltage as the second position voltage in the locked state, and sets the voltage obtained by adding the second voltage difference to the first position voltage as the second position voltage in the storage state.

[0009] The voltage when the movable part is in the first position is set as the first position voltage, and the second position voltage can be calculated by adding the voltage difference stored in the storage unit to the first position voltage. Even if the potentiometer sensor deteriorates, the difference between the position of the movable part recognized by the control device and the actual position of the movable part can be reduced.

[0010] Regarding the pallet locking device for solving the above problems, the link mechanism includes a first link arm that swings by the operation of the actuator, a connecting member fixed to the first link arm, and a second link arm that swings by the operation of the connecting member to swing the arm. The link mechanism further includes a switching member that is disposed on the swing locus of the first link arm and switches between turning on and turning off the switch by the swing of the first link arm.

Effect of the Invention

[0011] According to the present invention, the difference between the position of the movable part recognized by the control device and the actual position of the movable part can be reduced.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

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Figure 10

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Figure 13

DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the control device and the pallet locking device will be described. In the following description, "front", "rear", "left", "right", "up", and "down" are "front", "rear", "left", "right", "up", and "down" when the operator of the industrial vehicle is facing the forward direction during operation.

[0014] <Industrial vehicle> As shown in FIGS. 1 and 2, the industrial vehicle 10 is a picking lift. The picking lift is an example of a forklift. The industrial vehicle 10 includes a vehicle body 12, drive wheels 15, a traveling motor 16, driven wheels 17, and a handling device 31. The vehicle body 12 includes a main body portion 13 and two leg portions 14. The main body portion 13 is located at the front of the industrial vehicle 10. The drive wheels 15 are provided on the main body portion 13. The traveling motor 16 is provided inside the main body portion 13. The traveling motor 16 rotates the drive wheels 15. Thereby, the industrial vehicle 10 travels. The drive wheels 15 also serve as steering wheels. The two leg portions 14 extend rearward from the main body portion 13. The driven wheels 17 are provided on the two leg portions 14.

[0015] Industrial vehicle 10 is provided with a lifting section 21. The lifting section 21 includes a driver's cab 22, two forks 25, a wall section 26, a guard 27, an instrument panel 28, and a handling lever 29. The driver's cab 22 is the part where the operator of the industrial vehicle 10 boards. The driver's cab 22 is located at the rear of the industrial vehicle 10. The driver's cab 22 is provided between the two legs 14. The driver's cab 22 includes an upper plate 23 and a lower plate 24. The upper plate 23 and the lower plate 24 are arranged at intervals in the vertical direction. The upper surface of the upper plate 23 constitutes the upper surface of the driver's cab 22. The lower surface of the lower plate 24 constitutes the lower surface of the driver's cab 22. The forks 25 extend rearward from the driver's cab 22. The two forks 25 are arranged side by side at intervals in the left-right direction.

[0016] The wall section 26 extends upward from the front of the driver's cab 22. The upper part of the wall section 26 is net-shaped. Thereby, the forward visibility of the operator of the industrial vehicle 10 is ensured and the operator is protected. A guard 27 is provided on the rear surface of the wall section 26. The guard 27 protects the operator by surrounding the operator. An instrument panel 28 is provided on the rear surface of the wall section 26. A handling lever 29 is provided on the instrument panel 28. The handling lever 29 is operated when raising and lowering the lifting section 21.

[0017] As shown in FIG. 2, the handling device 31 includes a mast 32 and a mast drive section 35 that drives the mast 32. The mast 32 is located between the main body section 13 of the vehicle body 12 and the wall section 26 of the lifting section 21. The mast 32 includes an outer mast 33 and an inner mast 34. The outer mast 33 is fixed to the vehicle body 12. The inner mast 34 is vertically movable relative to the outer mast 33. A chain wheel (not shown) is provided at the upper part of the inner mast 34. A chain (not shown) is hung on the chain wheel. One end of the chain is attached to the outer mast 33. The other end of the chain is attached to the driver's cab 22. As the inner mast 34 moves up and down relative to the outer mast 33, the lifting section 21 moves up and down in the vertical direction.

[0018] The mast drive unit 35 includes a lift cylinder 36, a tank 37, a valve 38, a hydraulic pump 39, a handling motor 40, and an oil passage 41. The lift cylinder 36 is a hydraulic cylinder. By supplying and discharging hydraulic oil to and from the lift cylinder 36, the inner mast 34 moves vertically with respect to the outer mast 33. The tank 37 stores hydraulic oil. The lift cylinder 36 and the tank 37 are connected by the oil passage 41. The valve 38 is provided in the oil passage 41. When the handling lever 29 is operated, the valve 38 is in an open state. When the handling lever 29 is not operated, the valve 38 is in a closed state. When the valve 38 is in the open state, the lift cylinder 36 and the tank 37 communicate with each other. When the valve 38 is in the closed state, the lift cylinder 36 and the tank 37 do not communicate with each other.

[0019] The hydraulic pump 39 is provided between the valve 38 and the tank 37 in the oil passage 41. The hydraulic pump 39 is driven by the handling motor 40. The handling motor 40 drives when the handling lever 29 is operated. The handling motor 40 is a motor that can rotate in both directions. By switching the rotation direction of the handling motor 40, the operating state of the hydraulic pump 39 is switched. Thereby, while the hydraulic pump 39 supplies the hydraulic oil stored in the tank 37 to the lift cylinder 36 and returns the hydraulic oil filled in the lift cylinder 36 to the tank 37, the switching is performed. Thus, the handling motor 40 is a motor for raising and lowering the lifting unit 21.

[0020] <Pallet Locking Device> As shown in FIGS. 3 and 4, the industrial vehicle 10 includes a pallet locking device 50 that locks a pallet P supported by the forks 25. The pallet P includes an upper deck board D1 and a lower deck board D2. An insertion hole Pf is defined between the upper deck board D1 and the lower deck board D2.

[0021] The pallet locking device 50 is provided on the driver's cab 22. The driver's cab 22 includes two first mounting portions 42, two second mounting portions 43, a first support shaft 44, and a second support shaft 45. The two first mounting portions 42 protrude from the upper surface of the lower plate 24. The two first mounting portions 42 are arranged at intervals in the left - right direction. The two first mounting portions 42 support the first support shaft 44. The two second mounting portions 43 protrude from the upper surface of the lower plate 24 of the driver's cab 22. The two second mounting portions 43 are arranged at intervals in the left - right direction. The two second mounting portions 43 support the second support shaft 45.

[0022] The pallet locking device 50 includes a lock bar 51. The lock bar 51 includes a bar body 52, two arms 53, two mounting pieces 54, and an extension portion 55. The bar body 52 extends in the left - right direction. The bar body 52 is located behind the lower plate 24 of the driver's cab 22.

[0023] The two arms 53 are provided on the bar body 52. The two arms 53 are located at both ends of the bar body 52 in the left - right direction. The two arms 53 extend rearward from the bar body 52. The two arms 53 are located between the two forks 25.

[0024] The two mounting pieces 54 are provided on the bar body 52. The two mounting pieces 54 extend forward from the bar body 52. That is, the two mounting pieces 54 extend from the bar body 52 toward the lower plate 24. The two mounting pieces 54 are arranged at intervals in the left - right direction. The first support shaft 44 passes through the two mounting pieces 54. The lock bar 51 is supported by the first support shaft 44 so as to be swingable in the vertical direction. Specifically, the lock bar 51 is swingable about the first support shaft 44 as the rotation center.

[0025] The extension portion 55 extends forward from the bar body 52. The extension portion 55 extends further forward than the two attachment pieces 54. When the lock bar 51 swings so that the two arms 53 descend, the extension portion 55 ascends. On the other hand, when the lock bar 51 swings so that the arms 53 ascend, the extension portion 55 descends.

[0026] The pallet lock device 50 includes a pallet detection switch 56 and a detection switching member 57. The pallet detection switch 56 is used to detect that the two forks 25 have come into contact with the lower surface of the upper deck board D1 of the pallet P. The pallet detection switch 56 of the present embodiment is a limit switch. The detection switching member 57 switches between on and off of the pallet detection switch 56. The detection switching member 57 is attached to the extension portion 55. When the extension portion 55 ascends as the arm 53 descends, the detection switching member 57 also moves upward. When the detection switching member 57 moves upward, the pallet detection switch 56 turns on. When the extension portion 55 descends as the arm 53 ascends, the detection switching member 57 also moves downward. When the detection switching member 57 moves downward, the pallet detection switch 56 turns off.

[0027] The pallet lock device 50 includes a lock bar drive unit 61. The lock bar drive unit 61 is disposed between the upper plate 23 and the lower plate 24 of the driver's cab 22. Thereby, the lock bar drive unit 61 is built in the driver's cab 22.

[0028] The lock bar drive unit 61 presses the two arms 53 of the lock bar 51 against the upper surface of the lower deck board D2 of the pallet P by swinging the lock bar 51 in the vertical direction. The arm 53 presses against the lower deck board D2 of the pallet P to lock the pallet P together with the fork 25.

[0029] The lock bar drive unit 61 includes an actuator 62. The actuator 62 is an electric actuator, but a hydraulic cylinder may also be used. The actuator 62 includes, for example, a cylinder 63 and a cylinder motor 66. The actuator 62 is arranged such that the cylinder 63 extends in the front-rear direction. The cylinder 63 includes a cylinder tube 64 and a rod 65. The rod 65 is accommodated in the cylinder tube 64. The rod 65 is moved in the front-rear direction with respect to the cylinder tube 64 by the cylinder motor 66. When the rod 65 moves forward, the rod 65 protrudes from the cylinder tube 64. When the rod 65 moves backward, the rod 65 is retracted into the cylinder tube 64.

[0030] The lock bar drive unit 61 includes a link mechanism 71. The link mechanism 71 is arranged between the lock bar 51 and the actuator 62. The link mechanism 71 includes two first link arms 72, a support shaft 73, two second link arms 74, and a connecting member 75. The link mechanism 71 interlocks with the actuator 62 and swings the arm 53.

[0031] The two first link arms 72 are provided at intervals in the left-right direction. The two first link arms 72 are located between the two second attachment portions 43. A second support shaft 45 penetrates the lower end portions of the two first link arms 72. The rod 65 is inserted between the two first link arms 72. The support shaft 73 penetrates the upper end portions of the two first link arms 72 and the rod 65. Thereby, the first link arm 72 swings by the operation of the actuator 62. Due to the movement of the rod 65 in the front-rear direction with respect to the cylinder tube 64, the two first link arms 72 can swing in the front-rear direction about the second support shaft 45.

[0032] The two second link arms 74 are located between the two first attachment parts 42. The first support shaft 44 penetrates through the lower end parts of the second link arms 74. The second link arms 74 are supported by the first support shaft 44 so as to be swingable in the front-rear direction. The bar main body 52 of the lock bar 51 is arranged on the swing locus of the second link arms 74. Specifically, the bar main body 52 is arranged at a position where it contacts the second link arms 74 when the second link arms 74 swing backward. Thereby, the arm 53 can be swung by the link mechanism 71.

[0033] As shown in FIGS. 3 and 5, the connecting member 75 connects the first link arm 72 and the second link arm 74 to interlock the first link arm 72 and the second link arm 74. The connecting member 75 includes a joint 77, a connecting rod 80, a fixing member 83, a movable member 84, a spring 85, a plate 87, and two fixing nuts 93.

[0034] As shown in FIG. 5, the joint 77 is attached to the two second link arms 74. The joint 77 includes two first wall parts 78 and a second wall part 79. The two first wall parts 78 are provided at intervals in the left-right direction. The two first wall parts 78 sandwich the two second link arms 74 from the left and right directions. The two first wall parts 78 and the two second link arms 74 are connected. For example, the two first wall parts 78 and the two second link arms 74 are connected by a support shaft and are swingably connected about the support shaft. The second wall part 79 extends between the two first wall parts 78. The second wall part 79 is fixed to the two first wall parts 78 at a position in front of the second link arms 74.

[0035] As shown in FIGS. 3 and 5, the connecting rod 80 includes a first end part 81 and a second end part 82. The first end part 81 is fixed to the first link arm 72. The second end part 82 penetrates through the second wall part 79 and protrudes between the two first wall parts 78.

[0036] The fixing member 83 is fixed to the connecting rod 80. The fixing member 83 is provided between the first end portion 81 and the second wall portion 79. The fixing member 83 is, for example, a nut. The connecting rod 80 passes through the movable member 84. The movable member 84 is provided so as to be movable relative to the connecting rod 80 along the axial direction of the connecting rod 80. The movable member 84 is provided between the fixing member 83 and the second wall portion 79. The connecting rod 80 passes through the spring 85. The spring 85 is provided between the movable member 84 and the second wall portion 79.

[0037] The plate 87 includes a first portion 88, a second portion 89, a third portion 90, and a fourth portion 91. The first portion 88 is located between the two first wall portions 78. The second portion 89 is a portion extending in the left - right direction from the first portion 88. In the present embodiment, the second portion 89 extends leftward while inclining forward from the upper end portion of the first portion 88. The second portion 89 extends to a position outside the first wall portion 78 when the plate 87 is viewed from above. The third portion 90 extends forward from the second portion 89. The fourth portion 91 extends downward from the third portion 90.

[0038] The second end portion 82 of the connecting rod 80 is fixed to the plate 87. In the present embodiment, by sandwiching the connecting rod 80 passing through the first portion 88 with two fixing nuts 93, the second end portion 82 of the connecting rod 80 is fixed to the plate 87. Thereby, the plate 87 moves integrally with the connecting rod 80.

[0039] The link mechanism 71 converts the forward and backward movement of the rod 65 into the movement of the arm 53. When the rod 65 protrudes from the cylinder tube 64 and moves backward, the first link arm 72 swings about the second support shaft 45. Due to the swing of the first link arm 72, the connecting rod 80 fixed to the first link arm 72 moves integrally. At this time, although the connecting rod 80 and the joint 77 are not directly fixed, since the spring 85 is located between the fixing member 83 and the joint 77, the movement of the connecting rod 80 in the axial direction with respect to the joint 77 is restricted. A force from the connecting rod 80 is applied to the joint 77 via the fixing member 83 and the spring 85. As a result, the connecting rod 80 and the joint 77 move integrally to swing the second link arm 74. When the second link arm 74 swings, the arm 53 swings. Therefore, the elastic force of the spring 85 is set so as not to contract due to the movement of the connecting rod 80 in the axial direction in a state where the arm 53 is swinging.

[0040] When the rod 65 further protrudes from the cylinder tube 64 in a state where the swing of the arm 53 is restricted, since the movement of the joint 77 is restricted, the force applied from the connecting rod 80 to the spring 85 increases. For this reason, in a state where the swing of the arm 53 is restricted, the spring 85 contracts. As the spring 85 contracts, the protruding amount of the connecting rod 80 with respect to the second wall portion 79 increases. Thereby, the relative position of the plate 87 with respect to the second wall portion 79 changes. Specifically, when the plate 87 moves backward with respect to the second wall portion 79, the distance between the second wall portion 79 and the plate 87 increases.

[0041] The pallet locking device 50 includes a potentiometer 95. The potentiometer 95 includes a movable part 96 and a detection part 97. The position of the movable part 96 changes in conjunction with the forward and backward movement of the plate 87 with respect to the second wall part 79. The amount of movement of the plate 87 increases as the amount of contraction of the spring 85 increases. The greater the amount of contraction of the spring 85, the greater the pressing force applied from the arm 53 to the pallet P. The position of the movable part 96 changes due to the pressing force of the arm 53 on the pallet P.

[0042] As shown in FIG. 6, the movable part 96 of the present embodiment is a lever whose angle as a position changes in conjunction with the forward and backward movement of the plate 87 with respect to the second wall part 79. In the example shown in FIG. 6, as the plate 87 moves backward, the movable part 96 rotates upward. The amount of forward and backward movement of the plate 87 with respect to the second wall part 79 can also be regarded as the amount of contraction of the spring 85 or the amount of movement of the connecting rod 80 with respect to the second wall part 79. The detection part 97 detects the change in the position of the movable part 96 as a voltage. In the present embodiment, the voltage detected by the detection part 97 increases as the plate 87 moves backward.

[0043] The pallet locking device 50 includes a support member 99. The support member 99 supports the potentiometer 95. The support member 99 supports the potentiometer 95 such that the plate 87 and the potentiometer 95 move integrally in a state where the spring 85 is not contracted, and when the spring 85 contracts, the relative position of the plate 87 with respect to the movable part 96 changes to displace the movable part 96. In the present embodiment, the support member 99 supports the potentiometer 95 on one of the two first wall parts 78. In this case, it is preferable to support the potentiometer 95 on the first wall part 78 located in the direction in which the second part 89 of the first wall part 78 extends. In the present embodiment, the potentiometer 95 is supported on the left first wall part 78 of the two first wall parts 78. The support member 99 is, for example, a plate-like member.

[0044] As shown in FIG. 7, the pallet locking device 50 includes a switch 100. The switch 100 is, for example, a mechanical switch. The switch 100 is, for example, a limit switch. The switch 100 includes a shaft 101a. When the shaft 101a reaches a predetermined rotation angle, the on and off states of the limit switch are switched.

[0045] The pallet locking device 50 includes a switching member 101. The shaft 101a is fixed to the switching member 101. The switching member 101 extends from the shaft 101a toward one of the two first link arms 72. The switching member 101 includes a roller 102. One end of the switching member 101 is fixed to the shaft 101a, and the other end of the switching member 101 supports the roller 102 in a rotatable state. The roller 102 is disposed on the swing locus of one of the two first link arms 72. Specifically, the roller 102 is disposed in contact with the front surface of the first link arm 72. When the first link arm 72 swings forward, the switching member 101 is pushed by the first link arm 72. As a result, the shaft 101a rotates as the switching member 101 moves in conjunction with the first link arm 72. Thereby, the switch 100 is turned on. When the switching member 101 is not pushed by the first link arm 72, the switch 100 is turned off.

[0046] As shown in FIG. 4, during the loading and unloading operation of the industrial vehicle 10, the two forks 25 are inserted into the insertion holes Pf of the pallet P. The two arms 53 of the pallet locking device 50 are inserted into the insertion holes Pf.

[0047] As shown in FIG. 8, when the elevating unit 21 ascends with the two forks 25 and the two arms 53 inserted into the insertion hole Pf, the two arms 53 come into contact with the lower surface of the upper deck board D1 of the pallet P. The two arms 53 are pushed down by the upper deck board D1. As the two arms 53 are pushed down by the upper deck board D1, the extension part 55 ascends. The two forks 25 come into contact with the lower surface of the upper deck board D1 of the pallet P. The elevating unit 21 lifts the pallet P by ascending with the two forks 25 supporting the upper deck board D1.

[0048] The pallet locking device 50 assumes any one of an unlocked state, a locked state, and a loading state. The unlocked state is a state in which the pressing force by the arm 53 is not applied to the pallet P. That is, it is a state in which the pallet P is not locked by the arm 53. In the unlocked state, the pallet P can move upward. The position of the movable part 96 in the unlocked state is defined as the release position. The voltage detected by the detection unit 97 when the movable part 96 is at the release position is defined as the release voltage. The release position is an example of the first position. The release voltage is an example of the first position voltage.

[0049] As shown in FIG. 9, the locked state is a state in which the arm 53 is pressed against the lower deck board D2 of the pallet P. That is, it is a state in which the pallet P is locked by the arm 53. When the pressing force from the arm 53 is transmitted to the pallet P, the vertical movement of the pallet P is restricted. In the locked state, the position of the movable part 96 changes from the release position as the plate 87 moves. The position of the movable part 96 in the locked state is defined as the lock position. The voltage detected by the detection unit 97 when the movable part 96 is at the lock position is defined as the lock voltage. The lock position is an example of the second position. The lock voltage is an example of the second position voltage.

[0050] The pallet placement state is a state where the pallet P is placed on the floor in a locked state. The floor refers to the position where the pallet P is placed and includes the ground and the like. When the pallet P is placed on the floor in the locked state, a force from the floor is applied to the arm 53 via the pallet P. In the pallet placement state, the position of the movable part 96 changes from the locked position due to the force applied to the arm 53 from the floor via the pallet P. The position of the movable part 96 in the pallet placement state is defined as the pallet placement position. The voltage detected by the detection unit 97 when the movable part 96 is at the pallet placement position is defined as the pallet placement voltage. The pallet placement position is an example of the second position. The pallet placement voltage is an example of the second position voltage.

[0051] As shown in FIG. 10, the pallet locking device 50 includes a control device 110. The control device 110 includes a processing unit 111 and a storage unit 112. The processing unit 111 is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a DSP (Digital Signal Processor). The storage unit 112 includes a RAM (Random Access Memory), a ROM (Read Only Memory), and a non-volatile storage device. The storage unit 112 stores program codes or instructions configured to cause the processing unit 111 to execute processing. The storage unit 112, that is, the computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer. The control device 110 may be constituted by a hardware circuit such as an ASIC or an FPGA. The control device 110, which is a processing circuit, may include one or more processors operating according to a computer program, one or more hardware circuits such as an ASIC or an FPGA, or a combination thereof.

[0052] The control device 110 is connected to a pallet detection switch 56, a potentiometer 95, and a switch 100. The control device 110 can acquire the detection results of the pallet detection switch 56, the potentiometer 95, and the switch 100. The detection result of the pallet detection switch 56 is the on and off states of the pallet detection switch 56. The detection result of the potentiometer 95 is the voltage of the potentiometer 95. The detection result of the switch 100 is the on and off states of the switch 100. The voltage of the potentiometer 95 is the voltage detected by the detection unit 97. The control device 110 can control the actuator 62. Specifically, the control device 110 can cause the rod 65 to protrude from the cylinder tube 64 and retract the rod 65 into the cylinder tube 64 by controlling the rotation direction of the cylinder motor 66.

[0053] The detection results of the pallet detection switch 56, the potentiometer 95, and the switch 100 will be described together with the control performed by the control device 110. In the following description, the control after the fork 25 is inserted into the insertion hole Pf will be described.

[0054] As shown in FIG. 11, at time T0, the fork 25 is not in contact with the upper deck board D1. In this state, since the arm 53 is not in contact with the upper deck board D1, the extension portion 55 is in a lowered state. Therefore, the detection switching member 57 is in a lowered state, and the pallet detection switch 56 is off. At time T0, the pallet locking device 50 is in an unlocked state. At time T0, the switch 100 is on because the switching member 101 is pushed by the first link arm 72.

[0055] When the fork 25 contacts the upper deck board D1 at time T1, the arm 53 contacts the upper deck board D1, causing the extension part 55 to rise. As a result, the detection switching member 57 rises, turning on the pallet detection switch 56. When the pallet detection switch 56 turns on at time T1, the control device 110 starts control so that the pallet lock device 50 enters the locked state. The control device 110 controls the actuator 62 to project the rod 65 from the cylinder tube 64. That is, the rod 65 is moved rearward. As the rod 65 projects, the two first link arms 72 swing rearward about the second support shaft 45. With the swing of the first link arm 72, the switching member 101 that was being pushed by the first link arm 72 is no longer being pushed. As a result, the switch 100 switches from on to off at time T2.

[0056] When the switch 100 turns off at time T2, the voltage of the potentiometer 95 is the release voltage corresponding to the release position. That is, the position of the movable part 96 has not changed from the release position. The switch 100 is provided so that the on / off state switches when the movable part 96 is in the release position. The control device 110 continues to control the actuator 62 to project the rod 65 from the cylinder tube 64 after time T2. At time T3, the arm 53 contacts the lower deck board D2. From time T2 to time T3, the arm 53 swings toward the lower deck board D2 inside the insertion hole Pf. In this way, while the arm 53 is swinging, the spring 85 does not contract. In a state where the spring 85 is not contracted, the relative positional relationship between the plate 87 and the joint 77 is maintained by the spring 85. Therefore, the movable part 96 is maintained at the release position.

[0057] When the control device 110 further protrudes the rod 65 after time T3, the swing of the arm 53 is restricted by the lower deck board D2, so even if the rod 65 protrudes, the joint 77 cannot move. As a result, the force applied to the spring 85 from the connecting rod 80 increases. As the force applied to the spring 85 from the connecting rod 80 increases, the spring 85 contracts, and the pressing force of the arm 53 against the pallet P increases. Also, the plate 87 moves rearward with respect to the second wall portion 79. As the plate 87 moves rearward, the movable portion 96 is pushed by the plate 87. As a result, as the position of the movable portion 96 changes, the voltage of the potentiometer 95 increases. The position of the movable portion 96 changes as the pressing force of the arm 53 against the pallet P increases.

[0058] When the voltage of the potentiometer 95 reaches the lock voltage corresponding to the lock position at time T4, the control device 110 stops the actuator 62. As a result, the pallet locking device 50 enters the locked state.

[0059] The lowering of the fork 25 starts at time T5. When the pallet P contacts the floor, a force from the floor is applied to the arm 53 via the pallet P. The force applied to the arm 53 increases as the fork 25 lowers. A force that causes the arm 53 to swing upward is applied to the arm 53. Due to this force, a force is applied from the joint 77 to the spring 85, and the spring 85 further contracts. The further contraction of the spring 85 causes the plate 87 to move further rearward with respect to the second wall portion 79. As a result, the movable portion 96 is further pushed by the plate 87, and the voltage of the potentiometer 95 increases.

[0060] When the voltage of the potentiometer sensor 95 becomes the loading voltage corresponding to the loading position at time T6, the control device 110 recognizes that the loading is completed. The control device 110 controls the actuator 62 to retract the protruding rod 65 into the cylinder tube 64, reducing the amount of protrusion of the rod 65 from the cylinder tube 64. That is, the rod 65 is moved forward. As a result, the spring 85 that has been contracted is restored, and the amount of protrusion of the connecting rod 80 with respect to the second wall portion 79 decreases. As the plate 87 returns to its original position, the movable part 96 also returns to its original position. Thereby, the voltage of the potentiometer sensor 95 decreases.

[0061] At time T7, the voltage of the potentiometer sensor 95 becomes the release voltage corresponding to the release position. Thereby, the control device 110 can recognize that the movable part 96 has moved to the release position. Time T7 is the point in time when the arm 53 is separated from the lower deck board D2. When the control device 110 further retracts the rod 65 into the cylinder tube 64 after time T7, the arm 53 swings upward.

[0062] When the control of the actuator 62 is continued so that the rod 65 is retracted into the cylinder tube 64, the first link arm 72 swings forward about the second support shaft 45. As a result, the switching member 101 is pushed by the first link arm 72. The switching member 101 is pushed, and the switch 100 is turned on at time T8.

[0063] When the switch 100 is turned on at time T8, the control device 110 stops the actuator 62 at time T9 after a predetermined time has elapsed. As described above, the control device 110 recognizes the position of the movable part 96 based on the voltage obtained from the potentiometer sensor 95. The position of the movable part 96 represents the protruding amount of the rod 65 from the cylinder tube 64, in other words, the pressing force of the arm 53 against the pallet P. The control device 110 appropriately switches between the unlocked state, the locked state, and the storage state by controlling the pallet locking device 50 based on the voltage obtained from the potentiometer sensor 95.

[0064] <Release voltage, lock voltage, and storage voltage> The processing unit 111 of the control device 110 recognizes the release voltage by the switch 100, and calculates the lock voltage and the storage voltage using the release voltage. Then, it recognizes the position of the movable part 96 using these voltages.

[0065] The storage unit 112 stores the voltage difference between the first position voltage and the second position voltage. For example, the voltage difference is stored in the non-volatile storage device included in the storage unit 112. The non-volatile storage device is a rewritable storage device. The non-volatile storage device is, for example, a flash memory or an EEPROM (Electrically Erasable Programmable Read-Only Memory).

[0066] In this embodiment, the first position voltage is the release voltage. The second position voltage includes a lock voltage which is the second position voltage when in the locked state, and a storage position voltage which is the second position voltage when in the storage state. Therefore, the storage unit 112 stores the voltage difference corresponding to the two second position voltages. Specifically, the storage unit 112 stores a first voltage difference ΔV1 and a second voltage difference ΔV2. The first voltage difference ΔV1 is the difference between the voltage of the potentiometer 95 when the movable part 96 is in the unlocked state and the voltage of the potentiometer 95 when the movable part 96 is in the locked state. That is, the first voltage difference ΔV1 is the voltage difference between the release position and the lock position. The second voltage difference ΔV2 is the difference between the voltage when the movable part 96 is in the unlocked state and the voltage when the movable part 96 is in the storage state. That is, the second voltage difference ΔV2 is the voltage difference between the release position and the storage position.

[0067] As shown by line L1 in FIG. 12, when assembling the potentiometer 95, the operator examines the voltage characteristics of the potentiometer 95. The voltage characteristics of the potentiometer 95 are the amount of change in voltage with respect to the change in the position of the movable part 96. Then, the operator obtains the difference between the voltage corresponding to the release position and the voltage corresponding to the lock position from the voltage characteristics of the potentiometer 95 as the first voltage difference ΔV1. Similarly, the operator obtains the difference between the voltage corresponding to the release position and the voltage corresponding to the storage position as the second voltage difference ΔV2. The operator stores the obtained first voltage difference ΔV1 and second voltage difference ΔV2 in the storage unit 112. In this way, the first voltage difference ΔV1 and the second voltage difference ΔV2 are stored in the storage unit 112.

[0068] When the switch 100 is turned on and off, the processing unit 111 of the control device 110 acquires the voltage of the potentiometer sensor 95 and uses this voltage as the release voltage. The processing unit 111 of the control device 110 sets the voltage obtained by adding the first voltage difference ΔV1 to the release voltage as the lock voltage. The processing unit 111 of the control device 110 sets the voltage obtained by adding the second voltage difference ΔV2 to the release voltage as the loading voltage. Then, the actuator 62 is controlled according to the release voltage, lock voltage, and loading voltage thus obtained. In the example shown in FIG. 11, the voltage obtained from the potentiometer sensor 95 at time T2 is used as the release voltage. Then, based on this release voltage, the lock voltage and the loading voltage are calculated. The processing unit 111 of the control device 110 may use the voltage obtained at time T8 as the release voltage and calculate the lock voltage and the loading voltage based on this release voltage.

[0069] In the present embodiment, as the position of the movable part 96 changes from the release position → the lock position → the loading position, the voltage of the potentiometer sensor 95 increases. For this reason, the first voltage difference ΔV1 and the second voltage difference ΔV2 are positive values. When the voltage of the potentiometer sensor 95 decreases as the position of the movable part 96 changes from the release position → the lock position → the loading position, the first voltage difference ΔV1 and the second voltage difference ΔV2 may be set as negative values. That is, "adding the first voltage difference ΔV1 and the second voltage difference ΔV2 to the release voltage" includes not only addition but also subtraction.

[0070] [Operation of the Present Embodiment] When the potentiometer sensor 95 deteriorates, the voltage characteristics of the potentiometer sensor 95 change. Due to the change in the voltage characteristics of the potentiometer sensor 95 accompanying the deterioration, the voltage corresponding to each of the release position, the lock position, and the loading position changes. Therefore, even when the voltage is determined in advance corresponding to each of the release position, the lock position, and the loading position, there is a possibility that the control device 110 may not be able to recognize the correct position due to the deterioration of the potentiometer sensor 95.

[0071] As shown by line L2 in FIG. 13, assume that the voltage characteristics of the potentiometer sensor 95 have changed due to deterioration. Suppose that the release voltage corresponding to the release position, the lock voltage corresponding to the lock position, and the loading voltage corresponding to the loading position are determined from the voltage characteristics of the potentiometer sensor 95 at the time of assembly. In this case, the position of the movable part 96 corresponding to the release voltage will be different between line L1 and line L2. Therefore, when the potentiometer sensor 95 deteriorates, the position of the movable part 96 when the release voltage is obtained will deviate from the release position. The same applies to the lock voltage and the loading voltage.

[0072] The inventor has found that for the first voltage difference ΔV1, which is the voltage difference between the release voltage and the lock voltage, and the second voltage difference ΔV2, which is the voltage difference between the release voltage and the loading voltage, there is no change or only a slight change regardless of whether the potentiometer sensor 95 is deteriorated. That is, even if the value of the voltage corresponding to the position of the movable part 96 changes, it has been found that the amount of change in the voltage with respect to the amount of change in the position of the movable part 96 is constant. Therefore, if the control device 110 can recognize the voltage of the potentiometer sensor 95 when the movable part 96 is in the release position, the lock voltage and the loading voltage can be calculated by using this voltage as a reference.

[0073] A switch 100 is provided so that the on and off states of the switch 100 are switched when the movable part 96 is in the release position. Thus, since the fact that the movable part 96 is in the release position can be recognized by the switch 100, the voltage at this time is used as the release voltage, and the lock voltage can be calculated by adding the first voltage difference ΔV1 to the release voltage. Also, the loading voltage can be calculated by adding the second voltage difference ΔV2 to the release voltage. In the example shown in FIG. 13, if the release voltage corresponding to line L2 can be recognized, the lock voltage corresponding to line L2 and the loading voltage corresponding to line L2 can be calculated. That is, the release voltage, the lock voltage, and the loading voltage corresponding to the voltage of the potentiometer sensor 95 after deterioration can be calculated.

[0074] [Effects of this Embodiment] (1) By providing the switch 100, the control device 110 can recognize that the movable part 96 is in the release position. The storage unit 112 stores the first voltage difference ΔV1 and the second voltage difference ΔV2. Thereby, the lock voltage and the loading voltage can be calculated based on the voltage of the potentiometer sensor 95 when the movable part 96 is in the release position. Even if the potentiometer sensor 95 deteriorates, the difference between the position of the movable part 96 recognized by the control device 110 and the actual position of the movable part 96 can be reduced.

[0075] (2) The control device 110 is provided in the pallet locking device 50. Since the control device 110 can correctly recognize the release position, the lock position, and the loading position, the pallet locking device 50 can be appropriately controlled. For example, if the lock position cannot be correctly recognized, there is a possibility that the pressing force from the arm 53 to the pallet P is insufficient or the pressing force from the arm 53 to the pallet P becomes excessive. If the loading position cannot be correctly recognized, even when the pallet P is placed on the floor, there may be a case where it cannot be determined that it has been loaded. On the other hand, by correctly recognizing the release position, the lock position, and the loading position, such a situation can be suppressed from occurring.

[0076] (3) The switch 100 is switched between on and off by a link mechanism 71 interlocked with the actuator 62. Since the position of the movable part 96 changes with the movement of the link mechanism 71 interlocked with the actuator 62, there is a correlation between the link mechanism 71 and the position of the movable part 96. Therefore, by providing the switch 100 so that the on and off of the switch 100 are switched according to the position of the link mechanism 71 when the movable part 96 is in the release position, the on and off of the switch 100 can be switched by the link mechanism 71.

[0077] The embodiment can be implemented with the following modifications. The above embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range. ○ The switch 100 only needs to be provided so that its on and off states are switched by the movement of the link mechanism 71. For example, by arranging the switching member 101 on the swing locus of the second link arm 74, the on and off states of the switch 100 may be switched by the second link arm 74.

[0078] ○ The switch 100 only needs to have its on and off states switched when the movable part 96 is in the release position, and the on and off states may be switched by a member different from the link mechanism 71. For example, a switching member interlocked with the actuator 62 or the movable part 96 may be provided, and the on and off states of the switch 100 may be switched by the movement of this switching member.

[0079] ○ The switch 100 may turn off when the switching member 101 is pushed by the first link arm 72, and turn on when the switching member 101 is no longer pushed by the first link arm 72.

[0080] ○ The storage unit 112 may store a third voltage difference, which is the voltage difference between the lock voltage and the standby voltage, instead of the second voltage difference ΔV2. In this case, the control device 110 uses the voltage at the time when the on and off states of the switch 100 are switched as the release voltage, and uses the voltage obtained by adding the first voltage difference ΔV1 to the release voltage as the lock voltage. The control device 110 uses the voltage obtained by adding the third voltage difference to the lock voltage as the standby voltage. In this case, the second position is the lock position. The second position voltage is the lock voltage. The voltage difference is the first voltage difference ΔV1.

[0081] ○ The control device 110 may be provided in any device as long as it is a device equipped with the potentiometer sensor 95. For example, the potentiometer sensor 95 may be provided in the industrial vehicle 10. The first position and the second position only need to be set according to the device where the potentiometer sensor 95 is provided. For example, when detecting the position of the actuator by the potentiometer sensor 95, the first position and the second position may be set corresponding to the position of the actuator.

[0082] ○ The pallet locking device 50 may be provided on a forklift different from the picking lift. ○ The pallet locking device 50 may not be provided with the pallet detection switch 56. In this case, locking and unlocking of the pallet P may be switched by an operation of an operator of the industrial vehicle 10. In this case, the control device 110 may not recognize that the loading has been performed. In other words, it is sufficient that the control device 110 can recognize that the movable part 96 has reached the release position and the lock position. Therefore, it is sufficient that the first voltage difference ΔV1 is stored in the storage unit 112 as a voltage difference, and it is sufficient that the control device 110 can calculate the lock voltage from the release voltage.

[0083] ○ The pallet detection switch 56 may be turned off when the detection switching member 57 moves upward, and may be turned on when the detection switching member 57 moves downward. ○ The storage unit in which the voltage difference is stored may be an external storage device such as a hard disk drive or a solid state drive.

Explanation of Reference Numerals

[0084] P... pallet, 25... fork, 50... pallet locking device, 53... arm, 62... actuator, 71... link mechanism, 72... first link arm, 74... second link arm, 75... connecting member, 95... potentiometer, 96... movable part, 100... switch, 110... control device, 111... processing unit, 112... storage unit.

Claims

1. A processing unit that recognizes the position of the movable part by obtaining the voltage from a potentiometer that detects the position of the movable part by converting the change in the position of the movable part into a voltage; A storage unit that stores a voltage difference between a first position voltage that is the voltage when the movable part is in the first position and a second position voltage that is the voltage when the movable part is in the second position; and The processing unit Obtains a detection result of a switch that switches between on and off when the movable part is in the first position, and sets the voltage obtained from the potentiometer when the on and off are switched as the first position voltage; A control device that sets a voltage obtained by adding the voltage difference to the first position voltage as the second position voltage.

2. The control device is provided in a pallet locking device that locks a pallet supported by a fork, The pallet locking device An actuator; An arm pressed against the pallet; A link mechanism that interlocks with the actuator and swings the arm; and The position of the movable part changes due to the pressing force of the arm against the pallet, The first position is the position of the movable part in an unlocked state where the pallet is not locked by the arm, The second position includes the position of the movable part in a locked state where the pallet is locked by the arm and the position of the movable part in a state where the pallet is placed on the floor, The voltage difference includes a first voltage difference that is a difference between the voltage in the unlocked state and the voltage in the locked state, and a second voltage difference that is a difference between the voltage in the unlocked state and the voltage in the placed state. The control device according to claim 1.

3. A pallet locking device that locks a pallet supported by a fork, An actuator; An arm pressed against the pallet; A link mechanism that interlocks with the actuator and swings the arm; It has a movable part whose position changes due to the pressing force of the arm against the pallet, and a potentiometer that detects the position of the movable part by converting the change in the position of the movable part into a voltage. A control device having a processing unit that recognizes the position of the movable part by acquiring the voltage from the potentiometer sensor, and a storage unit that stores a voltage difference between a first position voltage, which is the voltage when the movable part is in the first position, and a second position voltage, which is the voltage when the movable part is in the second position. A switch that is switched between on and off by the movement of the link mechanism, and the switch is switched between on and off when the movable part is in the first position. The first position is the position of the movable part in an unlocked state where the pallet is not locked by the arm. The second position includes the position of the movable part in a locked state where the pallet is locked by the arm and the position of the movable part in a storage state where the pallet is placed on the floor. The voltage difference includes a first voltage difference that is the difference between the voltage in the unlocked state and the voltage in the locked state, and a second voltage difference that is the difference between the voltage in the unlocked state and the voltage in the storage state. The processing unit Sets the voltage acquired from the potentiometer sensor when the switch is switched between on and off as the first position voltage. Sets the voltage obtained by adding the first voltage difference to the first position voltage as the second position voltage when in the locked state. A pallet locking device that sets the voltage obtained by adding the second voltage difference to the first position voltage as the second position voltage when in the storage state.

4. The link mechanism A first link arm that swings by the operation of the actuator. A connecting member fixed to the first link arm. A second link arm that swings the arm by swinging due to the operation of the connecting member. The pallet locking device according to claim 3, further comprising a switching member that is disposed on the swinging locus of the first link arm and switches the switch between on and off by the swinging of the first link arm.

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