Forklift

Abstract

Provided is a forklift capable of accurately ascertaining the position of a cargo on a fork. A forklift (10) is provided with: a vehicle body; a cargo handling device provided in the vehicle body; the cargo handling device is provided with a fork which is provided with a bearing part capable of bearing the cargo and a standing part extending upwards from the base end of the bearing part. The goods detection device can detect goods on the forks; and a controller (60) connected to the cargo detection device. The cargo detection device is provided with: a shaft member that is pivotally supported by a fork; the arm component can be in contact with the goods on the fork and can swing by taking the shaft component as a fulcrum; and an angle detection sensor (43) capable of detecting the rotation angle of the arm member. The controller (60) has a distance calculation unit (62) that, when the arm member rotates due to contact between the cargo and the arm member, calculates the distance between the cargo and the standing portion in the longitudinal direction of the carrying portion on the basis of the rotation angle detected by the angle detection sensor (43).

Description

Technical Field

[0001] The present invention relates to a forklift. Background Art

[0002] As a conventional forklift technology, for example, the forklift cargo position detection device disclosed in Patent Document 1 is known. The forklift cargo position detection device disclosed in Patent Document 1 is a cargo position detection device provided on the forklift and comprises: a lever rotatably mounted on a fork; a cam that rotates as the lever rotates in response to pressure from a workpiece; a switch controlled according to the rotation angle of the cam; and a detection unit that detects the position of the workpiece on the fork based on the state of the switch. If the rotation angle of the cam is below a first threshold, the switch maintains a first state; if the rotation angle of the cam is between the first and second thresholds, the switch maintains a second state; and if the rotation angle of the cam is above the second threshold, the switch maintains the first state. The detection unit detects an abnormality in the cargo position when the switch returns to the first state after transitioning from the first state to the second state.

[0003] According to the forklift cargo position detection device disclosed in Patent Document 1, when the workpiece is positioned appropriately on the fork, the cam's rotation angle reaches a value between a first threshold and a second threshold, causing the switch to transition from the first state to the second state. Furthermore, when the workpiece is too close to the base, the cam's rotation angle exceeds the second threshold, causing the switch to transition from the second state to the first state. Thus, the detection unit can detect both the placement of the workpiece in the appropriate position on the fork and the proximity of the workpiece to the base by monitoring the output of a single switch. The forklift cargo position detection device disclosed in Patent Document 1 excels in providing a function for preventing the workpiece from contacting the forklift base, etc., using a simple configuration.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-193255 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, the forklift cargo position detection device disclosed in Patent Document 1 merely uses the ON / OFF state of a limit switch to detect any abnormalities in the cargo on the forks. However, in recent years, there has been a demand for more accurate detection of the location of cargo picked up by the forks. In particular, with the advancement of autonomous driving for forklifts, there is a strong desire to accurately detect the location of cargo on the forks in real time.

[0009] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a forklift capable of accurately grasping the position of a load on a fork.

[0010] Solutions for solving problems

[0011] In order to solve the above problems, the present invention is a forklift comprising: a vehicle body; a cargo loading and unloading device provided on the vehicle body; a fork provided on the cargo loading and unloading device, the fork comprising a load-bearing portion capable of carrying cargo and an upright portion extending upward from a base end of the load-bearing portion; a cargo detection device capable of detecting cargo on the fork; and a controller connected to the cargo detection device. The forklift is characterized in that the cargo detection device comprises: a shaft member axially supported by the fork; an arm member capable of contacting cargo on the fork and swinging about the shaft member as a fulcrum; and an angle detection sensor capable of detecting a rotation angle of the arm member, wherein the controller comprises a distance calculation unit that calculates a distance between the cargo and the upright portion in the longitudinal direction of the load-bearing portion of the load-bearing portion based on the rotation angle detected by the angle detection sensor when the arm member rotates due to contact between the cargo and the arm member.

[0012] In the present invention, when the load on the fork contacts the arm member, the arm member rotates due to the displacement caused by the swinging motion. As the arm member rotates, the angle detection sensor detects the rotation angle of the arm member. A distance calculation unit included in the controller calculates the distance between the load on the load-bearing portion and the upright portion based on the rotation angle detected by the angle detection sensor. This allows the controller to accurately determine the position of the load on the fork.

[0013] Furthermore, in the forklift described above, the angle detection sensor may be configured to detect the rotation angle of the arm member continuously or in stages.

[0014] In this case, since the angle detection sensor detects the rotation angle of the arm member continuously or in stages, the controller can continuously or in stages grasp the position of the load on the fork.

[0015] Furthermore, the forklift may include a first abnormality alarm for indicating that the state of the cargo is abnormal, and the controller may activate the abnormality alarm when the cargo moves toward the top end of the load-bearing portion.

[0016] In this case, if the cargo moves toward the top of the load-bearing section during travel or loading / unloading, the rotation angle detected by the angle detection sensor decreases. Therefore, the controller activates the first abnormality alarm when the cargo moves toward the top of the load-bearing section. As a result, it is possible to detect abnormalities in the cargo's position relative to the forks.

[0017] Furthermore, the forklift described above may be configured as follows: a second abnormality alarm indicating that the state of the cargo is abnormal is provided, wherein each of the pair of forks is provided with the angle detection sensor, and the controller activates the second abnormality alarm when the difference between the rotation angle detected by one angle detection sensor and the rotation angle detected by the other angle detection sensor is greater than a threshold value.

[0018] In this case, since each pair of forks is equipped with an angle detection sensor, if the difference between the rotation angle detected by one angle detection sensor and the rotation angle detected by the other angle detection sensor exceeds a threshold, the controller can determine that the cargo on the forks is excessively tilted relative to the fork insertion direction and activate the second abnormality alarm. As a result, it is possible to detect abnormalities in the cargo position relative to the forks.

[0019] In addition, in the above-mentioned forklift, it can also be set as follows: the controller has a path setting unit that pre-sets a travel path suitable for the destination, and when the abnormality alarm is working, the travel path is reset based on the position of the cargo or the cargo loading and unloading device is controlled in a manner such that the fork's picking-up action is resumed.

[0020] In this case, since the controller resets the travel route based on the position of the cargo or controls the cargo handling device so as to resume the fork's pickup action when the abnormality alarm is activated, there is no need to perform an abnormal stop even if the position of the cargo is abnormal.

[0021] Furthermore, the forklift described above may be configured to be capable of unmanned driving by automatic driving.

[0022] In this case, since the forklift can be driven unmanned by automatic driving, it is possible to realize a forklift that can be driven unmanned and can accurately grasp the position of the load on the fork.

[0023] Effects of the Invention

[0024] According to the present invention, it is possible to provide a forklift capable of accurately grasping the position of a load on a fork. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a plan view of the forklift according to the first embodiment.

[0026] Figure 2 It is a side view of the forklift according to the first embodiment.

[0027] Figure 3 It is a perspective view showing the main part of the forklift according to the first embodiment.

[0028] Figure 4This is a perspective view of a cargo detection device on a forklift.

[0029] Figure 5 It is a schematic configuration diagram of a forklift according to the first embodiment.

[0030] Figure 6 It is a side view illustrating the position of the cargo on the fork.

[0031] Figure 7 It is a plan view showing the cargo placed obliquely on the forks.

[0032] Figure 8 It is a perspective view of a cargo detection device for a forklift according to a second embodiment.

[0033] Figure 9 It is a side view of a cargo inspection device according to a modified example.

[0034] Description of Reference Numerals

[0035] 10, 70 forklift

[0036] 11 Body

[0037] 12 Main body of the vehicle

[0038] 16 Travel motor

[0039] 17 drive wheels

[0040] 24 Cargo handling equipment

[0041] 28 (28R, 28L) fork

[0042] 31 bearing part

[0043] 32 Establishment Department

[0044] 36 front (standing part)

[0045] 39 shaft support

[0046] 40, 71 cargo detection device

[0047] 42 shaft components

[0048] 43 Angle detection sensor

[0049] 44, 72, 81 arm components

[0050] 51 fixed part

[0051] 52 movable parts

[0052] 54 arm main body

[0053] 57 Torsion coil spring (force applying member)

[0054] 60 Controller

[0055] 61 Path Setting Unit

[0056] 62 Distance calculation unit

[0057] 63 Discrimination

[0058] 64 Abnormal alarm

[0059] 73 Flat Plate

[0060] 74 side panel

[0061] P Pallet

[0062] W goods. DETAILED DESCRIPTION

[0063] (First embodiment)

[0064] The following describes a forklift according to a first embodiment with reference to the accompanying drawings. The forklift according to this embodiment is an unmanned forklift capable of autonomous driving, and is also capable of human operation. Furthermore, the forklift according to this embodiment is a reach-type forklift that is electrically driven. The directions of "front and back," "left and right," and "up and down" are illustrated with the forklift operator seated in the driver's seat and facing the forward direction of the forklift.

[0065] like Figure 1 As shown, the vehicle body 11 of the forklift 10 has a vehicle body main body 12 and a pair of left and right front legs 13 (13R, 13L) extending forward from the front portion of the vehicle body main body 12. The front legs 13 are provided with freely rotatable driven wheels 14 corresponding to the front wheels. The right driven wheel is referred to as the driven wheel 14R, and the left driven wheel is referred to as the driven wheel 14L. Figure 2 In the figure, only the left front extension leg 13 and the left driven wheel 14L are shown.

[0066] like Figure 1 As shown, a drive unit 15 having a travel motor 16 and a drive wheel 17 serving as a rear wheel is provided on the left side of the rear portion of the vehicle body 12. The travel motor 16 drives the drive wheel 17. The forklift 10 travels on the road surface F by the drive wheel 17. In addition, the drive unit 15 is provided with a steering motor (not shown) for steering the drive wheel 17. The vehicle body 12 is equipped with a battery (not shown) that can be charged and discharged. Figure 1 As shown in FIG. 1 , a caster 18 is provided on the right side of the rear portion of the vehicle body 12. The caster 18 is a freely rotatable wheel for further stabilizing the posture of the vehicle body 11.

[0067] like Figure 2As shown in FIG. 1 , a right support 20 and a left support 21 are provided on the vehicle body 12. A roof guard 22 is provided on the upper portion of the right support 20 and the left support 21. Figure 1 The top guard 22 is omitted in the figure.

[0068] Between the pair of forward legs 13 is a cargo handling device 24 that can move forward and backward freely relative to the vehicle body 12. The cargo handling device 24 includes an outer mast 25 supported by the left and right forward legs 13 and an inner mast 26 supported by the outer mast 25 so as to be raised and lowered. A lifting support 27 is supported on the inner mast 26 so as to be raised and lowered. A pair of left and right forks 28 are supported on the front of the lifting support 27. The upper ends of the forks 28 are pivotally supported on the lifting support 27 so as to be tiltable. Therefore, the forks 28 can tilt forward and backward. A lifting cylinder 29 is fixed to the rear of the outer mast 25 for raising and lowering the inner mast 26. A control valve 30 is mounted on the vehicle body 12 for supplying and discharging hydraulic oil to and from the lifting cylinder 29 of the cargo handling device 24.

[0069] Next, the fork 28 will be described. The right fork 28R of the left and right forks 28R and 28L will be described. The left fork 28L is symmetrical to the right fork 28R, and the description of the right fork 28R will be cited. Figure 3 As shown, the right fork 28R includes a load-bearing portion 31 capable of carrying cargo, and an upright portion 32 extending upward from the base end of the load-bearing portion 31. The load-bearing portion 31 is a portion extending forward and has an upper surface 33, a lower surface 34, and a pair of side surfaces 35. The upper surface 33 is a flat surface for carrying cargo. The thickness of the load-bearing portion 31 decreases as it moves from the base end (rear end) to the top end (front end). One of the pair of side surfaces 35 faces outward, and the other side surface 35 faces the left fork 28L. In addition, in this embodiment, the longitudinal direction of the load-bearing portion 31 is the same as the front-rear direction of the forklift 10.

[0070] The upright portion 32 extends upward from the base end of the support portion 31. The longitudinal direction of the upright portion 32 is approximately perpendicular to the longitudinal direction of the support portion 31. The upright portion 32 has a front face 36, a back face 37, and a pair of side faces 38. The front face 36 is the face against which cargo can come into contact. The back face 37 faces the cargo handling device 24. One of the pair of side faces 38 faces outward, while the other side face 38 faces the upright portion 32 of the left fork 28L. A cylindrical shaft support 39 is provided on the upper portion of the upright portion 32 and is pivotally supported by the lifting support member 27.

[0071] In this embodiment, a cargo detection device 40 is provided on the other side surface 38 of the upright portion 32 of the fork 28. Figure 4As shown, cargo detection device 40 includes a bracket 41, a shaft member 42, an angle detection sensor 43, and an arm member 44. Bracket 41 includes a plate-shaped base 45 fixed to side surface 38, a rod portion 46 protruding from base 45 in a direction substantially perpendicular to side surface 38, and a plate-shaped shaft support portion 47 fixed to rod portion 46. Shaft member 42 is pivotally supported by fork 28 via base 45 and shaft support portion 47.

[0072] The angle detection sensor 43 includes a cylindrical fixed portion 51 fixed to the shaft member 42 and a movable portion 52 that is pivotable about the shaft member 42. The shaft member 42 extends through the angle detection sensor 43. The angle detection sensor 43 uses a potentiometer, and the voltage continuously changes according to the rotation angle of the movable portion 52 relative to the fixed portion 51. The angle detection sensor 43 continuously outputs the voltage change corresponding to the rotation angle as a signal. In other words, the angle detection sensor 43 can detect the rotation angle of the arm member 44.

[0073] An arm member 44 formed from a metal rod is attached to the movable portion 52. The arm member 44 includes a base end portion 53 fixed to the movable portion 52 and an arm main portion 54 extending forward and downward from the base end portion 53. The axis of the base end portion 53 is approximately parallel to the axis of the shaft member 42, and the arm main portion 54 is bent approximately at a right angle from the base end portion 53 so that the axis of the arm main portion 54 faces forward and downward, thereby changing the direction of the axis. A bent portion 55 is provided between the end of the arm main portion 54 on the base end portion 53 side and the tip end, slightly changing the direction of the axis of the arm main portion 54.

[0074] The provision of the curved portion 55 allows the load to be brought closest to the upright portion 32 in the longitudinal direction of the support portion 31 when the arm member 44 swings most toward the upright portion 32 due to contact with the load. Furthermore, a notch 56 is formed in the pivot support portion 47 of the bracket 41. This notch 56 is used to prevent interference between the pivot support portion 47 and the base end portion 53 when the arm member 44 swings most toward the upright portion 32 due to contact with the load. The notch 56 is formed to match the trajectory of the pivot support portion 47 during the swinging of the arm member 44.

[0075] The cargo detection device 40 includes a torsion coil spring 57 as a biasing member. The torsion coil spring 57 applies a biasing force to the movable portion 52 of the angle detection sensor 43, keeping the arm member 44 oriented toward the tip of the support portion 31 of the fork 28. The shaft member 42 is inserted through the center of the torsion coil spring 57. One end of the torsion coil spring 57 is engaged with the base 45 of the bracket 41, while the other end of the torsion coil spring 57 is engaged with the movable portion 52 of the angle detection sensor 43. As the arm member 44 approaches the upright portion 32 due to contact with the cargo, the biasing force on the movable portion 52 increases. The magnitude of the biasing force is such that the cargo on the fork 28 does not move. In addition to the torsion coil spring 57, a compression coil spring, for example, may also be used as the biasing member.

[0076] In addition, the vehicle body 12 houses a controller 60 that controls various parts of the vehicle body 11. The controller 60 includes a CPU as a calculation processing unit, a RAM and a ROM as a storage unit, and a communication unit that communicates with various parts of the vehicle body and the outside. The controller 60 realizes various functions by, for example, loading a program stored in the ROM of the storage unit into the RAM of the storage unit, and having the CPU execute the program loaded in the RAM. The controller 60 may also include dedicated hardware that performs at least a part of the various processes, such as an application-specific integrated circuit (ASIC). The controller 60 can be configured as a circuit including one or more processors that operate according to a computer program, one or more dedicated hardware circuits such as an ASIC, or a combination thereof.

[0077] The forklift 10 of this embodiment can be driven automatically without human intervention. Figure 5 As shown, the controller 60 includes a route setting unit 61. The route setting unit 61 has the function of presetting a route for the forklift 10 to travel unmanned via automated driving. Specifically, the controller 60 stores a map containing routes for unmanned driving of the forklift 10. The controller 60 selects and pre-sets a route suitable for the forklift 10's destination based on conditions such as travel distance and travel speed.

[0078] The controller 60 includes a distance calculation unit 62 and a determination unit 63. The controller 60 is connected to the cargo detection device 40. The distance calculation unit 62 has a function of calculating the distance based on the rotation angle detected by the angle detection sensor 43. Figure 6 The distance D between the back of the cargo W in the longitudinal direction of the load-bearing portion 31 and the front face 36 of the upright portion 32 is calculated using a trigonometric function. Specifically, the distance calculation unit 62 calculates the distance D from the rotation angle of the movable portion 52 of the angle detection sensor 43 relative to the fixed portion 51. The distance calculation unit 62 continuously calculates the distance D according to the change in the rotation angle. Figure 6As shown in FIG, the cargo W includes not only the cargo body but also the pallet P carrying the cargo body. Figure 6 , for convenience of explanation, the pallet P is shown in a broken state at the insertion opening into which the fork 28 can be inserted.

[0079] The determination unit 63 has a function of determining whether there is any abnormality in the cargo W supported on the fork 28. Specifically, the determination unit 63 monitors the calculated distance D and determines that there is an abnormality when the distance D increases over time. Figure 6 As shown in FIG. 2 , the cargo W indicated by the two-dot chain line moves forward to the position of the cargo W indicated by the solid line. In this case, since the cargo W moves toward the top of the fork 28, there is a possibility that the cargo W falls from the fork 28. The determination unit 63 determines that an abnormality has occurred when the difference between the angle of the right angle detection sensor 43 and the angle of the left angle detection sensor 43 is greater than a threshold value. In this case, for example, Figure 7 As shown, the cargo W is excessively tilted relative to the longitudinal direction (front-rear direction) of the carrying portion 31 of the fork 28 in a plan view.

[0080] like Figure 5 As shown, the controller 60 is connected to the driving motor 16 and the control valve 30, and is also connected to an abnormality alarm 64. The abnormality alarm 64 is controlled by the controller 60. The abnormality alarm 64 can be, for example, at least one of a warning buzzer that generates a warning sound to the surroundings and a warning light (for example, a red rotating light or a stacked indicator light) that lights up when an abnormality occurs. When the determination unit 63 determines that there is an abnormality in the cargo W, the controller 60 activates the abnormality alarm 64. The abnormality alarm 64 of this embodiment corresponds to a first abnormality alarm and a second abnormality alarm that indicate that the state of the cargo is abnormal. The first abnormality alarm indicates an abnormality in the state of the cargo caused by the movement of the cargo relative to the fork 28, and the second abnormality alarm indicates an abnormality in the state of the cargo caused by the tilt of the cargo on the fork 28.

[0081] In the event of an abnormality where the distance D increases over time, the controller 60 slows down and stops the forklift 10. Furthermore, in the event of an abnormality where the difference in angle between the left and right angle detection sensors 43 exceeds a threshold, the controller 60 resets the travel path based on the position of the cargo W or controls the cargo handling device 24 to resume the pickup action of the forks 28. The travel path is reset by the path setting unit 61, for example, to a travel path that causes the forklift 10 to move diagonally in accordance with the tilt of the cargo W. Furthermore, if the cargo W is excessively tilted in the longitudinal direction of the load-bearing portion 31, resetting the travel path may not resolve the issue. In this case, the controller 60 controls the control valve 30 to activate the lift cylinder 29 in such a way that the pickup action is resumed, thereby resolving the excessive tilt of the cargo W in the longitudinal direction of the load-bearing portion 31.

[0082] Next, the function of the forklift 10 of this embodiment will be described. The forklift 10 performs unmanned driving through automatic driving to carry out cargo loading and unloading operations. The driving path for unmanned driving through automatic driving is pre-set in the path setting unit 61 so that it becomes a driving path suitable for the destination. When picking up cargo W including a pallet P, when the fork 28 is inserted into the pallet P, the back of the cargo W abuts against the arm member 44 of the cargo detection device 40. Furthermore, when the fork 28 is inserted deeper into the pallet P, the arm member 44 is pressed against the cargo W and displaced rearward relative to the force of the torsion coil spring 57, causing the movable portion 52 of the angle detection sensor 43 to rotate relative to the fixed portion 51.

[0083] In the angle detection sensor 43, as the movable portion 52 rotates relative to the fixed portion 51, the voltage fluctuates in accordance with the rotation angle. This voltage fluctuation is continuously transmitted as a signal. In the controller 60, upon receiving the signal from the angle detection sensor 43, the distance calculation unit 62 calculates the distance D between the back surface of the cargo W and the front surface 36 of the upright portion 32 based on the rotation angle. The distance calculation unit 62 continuously calculates the distance D as the arm member 44 moves closer to the front surface 36 of the upright portion 32. As the cargo W approaches the front surface 36 of the upright portion 32, the rotation angle increases and the distance D decreases. When the arm member 44 is at its maximum displacement (maximum rotation angle), the distance D is zero.

[0084] The angle detection sensors 43 provided on the pair of left and right forks 28 detect their respective rotation angles, and the distance calculation unit 62 calculates the distance D between the back surface of the cargo W on the pair of forks 28 and the front surface 36 of the upright portion 32 .

[0085] In the controller 60, the distance calculator 62 continuously calculates the distance D corresponding to the displacement of the arm member 44, and the determination unit 63 determines whether there is any abnormality in the cargo W. The determination unit 63 monitors the calculated distance D and determines that an abnormality has occurred if the distance D increases over time. If the determination unit 63 determines that an abnormality has occurred, the controller 60 activates the abnormality alarm 64 and controls the travel motor 16 to decelerate and stop the forklift 10.

[0086] Furthermore, the determination unit 63 detects an abnormality when the difference in angle between the left and right angle detection sensors 43 exceeds a threshold. In this case, the abnormality annunciator 64 is activated because the cargo W is excessively tilted relative to the longitudinal direction of the fork 28's support portion 31 when viewed from above. In the event of an abnormality where the difference in angle between the left and right angle detection sensors 43 exceeds the threshold, the controller 60 resets the travel path based on the position of the cargo W or controls the cargo handling device 24 to resume the pickup operation of the fork 28.

[0087] The travel path is reset by the path setting unit 61, and for example, the travel path is set so that the forklift 10 moves diagonally according to the inclination of the cargo W (see Figure 7 Furthermore, if the load W is tilted excessively, resetting the travel path may not resolve the situation. However, in this case, the controller 60 controls the cargo handling device 24 to cause the forks 28 to resume the cargo pickup operation. After resetting the travel path or resuming the cargo pickup operation, the controller 60 deactivates the abnormality alarm 64. Furthermore, if the determination unit 63 determines that there is no abnormality with the load, the forklift 10 continues unmanned driving under automatic control.

[0088] The forklift 10 of this embodiment has the following effects.

[0089] (1) When the cargo W on the fork 28 contacts the arm member 44, the arm member 44 rotates relative to the shaft member 42. When the arm member 44 rotates, the angle of rotation is detected by the angle detection sensor 43. The distance calculation unit 62 included in the controller 60 calculates the distance between the cargo W on the load-bearing portion 31 and the upright portion 32 based on the angle of rotation detected by the angle detection sensor 43. Therefore, the controller 60 can accurately grasp the position of the cargo W on the fork 28. Therefore, even if the shape of the insertion port changes for each pallet type, for example, the position of the cargo W on the fork 28 can be accurately grasped, and robustness can be ensured.

[0090] (2) Since the angle detection sensor 43 continuously detects the rotation angle, the controller 60 can continuously grasp the position of the cargo W on the fork 28 .

[0091] (3) The controller 60 includes an abnormality alarm 64 that indicates that the state of the cargo W on the fork 28 is abnormal. The controller 60 activates the abnormality alarm 64 when the cargo W moves toward the top of the load-bearing portion 31. Therefore, when the cargo W moves toward the top of the load-bearing portion 31 during travel or cargo loading / unloading, the rotation angle of the arm member 44 detected by the angle detection sensor 43 decreases. Therefore, the controller 60 activates the abnormality alarm 64 when the cargo W moves toward the top of the load-bearing portion 31. As a result, it is possible to detect abnormalities in the position of the cargo W relative to the fork 28.

[0092] (4) If the difference between the rotation angle detected by one angle detection sensor 43 and the rotation angle detected by the other angle detection sensor 43 is greater than a threshold value, the controller 60 can determine that the cargo W on the fork 28 is excessively tilted relative to the insertion direction of 28 and activate the abnormality alarm 64. As a result, an abnormality in the position of the cargo W relative to the fork 28 can be detected.

[0093] (5) The controller 60 includes a route setting unit 61 that pre-sets a travel route as a predetermined travel route. When the abnormality alarm 64 is activated, the controller 60 resets the travel route based on the position of the cargo W or controls the cargo handling device 24 so as to resume the pickup operation of the fork 28. Therefore, since the controller 60 resets the travel route based on the position of the cargo W or controls the cargo handling device 24 so as to resume the pickup operation of the fork 28 when the abnormality alarm 64 is activated, even if the position of the cargo W is abnormal, it is not necessary to perform an abnormal stop.

[0094] (6) Since the forklift 10 can be driven unmanned by automatic driving, it is possible to realize a forklift that can be driven unmanned and can accurately grasp the position of the cargo W on the forks 28 .

[0095] (Second embodiment)

[0096] Next, a forklift according to a second embodiment will be described. In this embodiment, the configuration of the arm member differs from that of the first embodiment. In this embodiment, the same configuration as that of the first embodiment will be referred to the description of the first embodiment, and the same reference numerals will be used.

[0097] like Figure 8As shown, a cargo detection device 71 is provided on the side surface 38 of the right fork 28R of the forklift 70. The cargo detection device 71 includes a bracket 41, a shaft member 42, an angle detection sensor 43, a torsion coil spring 57, and an arm member 72. The arm member 72 is formed by bending a metal plate. The arm member 72 includes a flat plate portion 73 that can abut against cargo W and a pair of side plate portions 74 folded from both sides of the flat plate portion 73. The arm member 72 is fixed to the movable portion 52 of the angle detection sensor 43. Therefore, the arm member 72 is supported so as to be rotatable relative to the shaft member 42. Compared with the first embodiment, the length of the fixed portion 51 and the rod body portion 46 is changed to match the plate width of the flat plate portion 73 of the arm member 72.

[0098] When the arm member 72 is displaced to the maximum (the rotation angle is the maximum), the front surface of the flat plate portion 73 of the arm member 72 is substantially flush with the front surface 36 of the upright portion 32. Although not shown, the left fork 28L also includes a cargo detection device 71.

[0099] This embodiment achieves the same effects as those of Embodiment 1. In addition, in this embodiment, the arm member 72 is formed of a metal plate, and therefore is less likely to deform than the rod-shaped arm member 44 and has excellent durability.

[0100] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist of the invention. For example, the following modifications are also possible.

[0101] In the above embodiment, a cargo detecting device is provided on each of the pair of forks, but the present invention is not limited thereto. For example, the cargo detecting device may be provided on only one of the pair of forks.

[0102] In the above embodiment, the angle detection sensor continuously detects the rotation angle of the arm member, but the present invention is not limited to this. The angle detection sensor may detect the rotation angle in stages rather than continuously.

[0103] In the above embodiment, the angle detection sensor is provided on the upright portion of the fork, but the present invention is not limited thereto. Figure 9 As shown, the angle detection sensor 43 may be provided on, for example, the side surface 35 of the support portion 31 of the fork 28. In this case, an arm member 81 is provided on the movable portion 52 of the angle detection sensor 43, but the arm member 81 extends upward and forward from the side surface 35 of the support portion 31. Therefore, even in cases where it is not possible to provide an angle detection sensor on the upright portion of the fork, an angle detection sensor can be provided on the fork.

[0104] In the above embodiment, the forklift is equipped with an abnormality detector, but this is not limiting. For example, a forklift without an abnormality detector may also be used. In this case, even if the determination unit identifies an abnormality with the cargo, if the abnormality is related to the cargo moving forward of the load-carrying section, the forklift will be decelerated and stopped. If the cargo tilts in the longitudinal direction of the load-carrying section, the forklift can simply reset its travel path or perform the cargo pickup operation again.

[0105] In the above embodiment, the abnormality alarm 64 serves as both the first and second abnormality alarms, but this is not limiting. For example, a first abnormality alarm indicating an abnormality caused by the movement of the cargo and a second abnormality alarm indicating an abnormality caused by the tilt of the cargo may be separately provided. In this case, the angle detection sensor may be a common angle detection sensor, with only the conditions for the controller's determination varying.

Claims

1. A forklift comprising: body; The cargo loading and unloading device provided on the vehicle body; The fork provided in the cargo handling device includes a carrying portion capable of carrying cargo and an upright portion extending upward from a base end of the carrying portion; a cargo detection device capable of detecting cargo on the fork; as well as a controller connected to the cargo detection device, The forklift is characterized in that The cargo detection device comprises: a shaft member axially supported by the fork; an arm member capable of contacting cargo on the fork and swinging with the shaft member as a fulcrum; as well as an angle detection sensor capable of detecting the rotation angle of the arm member, The controller includes a distance calculation unit that calculates the distance between the load and the upright portion in the longitudinal direction of the load-bearing portion based on a rotation angle detected by the angle detection sensor when the arm member rotates due to contact between the load and the arm member.

2. The forklift according to claim 1, characterized in that The angle detection sensor detects the rotation angle of the arm member continuously or in stages.

3. The forklift according to claim 1 or 2, characterized in that: A first abnormality alarm device is provided to indicate that the state of the cargo is abnormal. The controller activates the first abnormality alarm when the cargo moves toward the top end of the load-bearing portion.

4. The forklift according to claim 1 or 2, characterized in that: A second abnormality alarm device is provided to indicate that the state of the cargo is abnormal. The pair of forks are each provided with the angle detection sensor. The controller activates the second abnormality annunciator when a difference between a rotation angle detected by one of the angle detection sensors and a rotation angle detected by the other angle detection sensor is equal to or greater than a threshold value.

5. The forklift according to claim 4, characterized in that The controller includes a route setting unit for presetting a driving route suitable for a destination. When the second abnormality alarm is activated, the travel route is reset based on the position of the cargo or the cargo handling device is controlled so that the picking-up operation of the fork is resumed.

6. The forklift according to claim 3, characterized in that It can be driven autonomously.

7. The forklift according to claim 5, characterized in that It can be driven autonomously.

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