Industrial vehicle

Abstract

An industrial vehicle (1) is provided with: a lateral displacement mechanism that laterally displaces the position of a pair of forks (13) in the horizontal direction; a distance sensor that is provided on a side surface in the horizontal direction of at least one fork (13) of the pair of forks (13) and that detects the distance from the side surface to the object to be detected; and a control unit (23) that controls the lateral movement of the pair of forks (13) by the lateral movement mechanism on the basis of the detection result of the distance sensor. The control unit (23) stores an initial value for the distance between the side surface of the fork (13) and the inner wall surface defining the insertion hole at the start of the side movement by the side movement mechanism, and when the distance between the side surface of the fork (13) and the inner wall surface varies from the initial value (ds) during the execution of the side movement by the side movement mechanism. The side movement by the side movement mechanism is stopped.

Description

Technical Field

[0001] The present disclosure relates to industrial vehicles. Background Art

[0002] For example, Japanese Patent Application Publication No. 2021-143039 discloses a forklift having a side shift device. The side shift device disclosed in Japanese Patent Application Publication No. 2021-143039 includes: a lifting bracket that is raised and lowered along a mast; a backrest that is provided on the lifting bracket and has a fork mounted thereon; and a side shift mechanism that causes the fork to side shift in a horizontal direction (e.g., in the width direction of the vehicle body). Summary of the invention

[0003] When loading goods onto a cargo bed of a truck or the like by means of the above-mentioned industrial vehicle, a method is adopted in which adjacent pallets are brought into contact with each other by means of a side shift mechanism to arrange the pallets in a manner that does not create gaps between the pallets. By eliminating the gaps between the pallets, the utilization efficiency of the cargo bed space can be improved, and the shaking of the goods caused by vibrations during transportation can be suppressed. On the other hand, in the scenario of loading goods, if the side shift amount becomes excessive when the side shift action of the fork is automatically performed, it is considered that the pallet being loaded may hit other loaded pallets. In this case, there is the possibility that the friction force when the pallet slides on the fork, or the reaction force of the fork pressing the inner wall surface of the pallet after the pallet hits other pallets is applied to the fork, and a load is applied to the mechanism on the fork side (the fork itself or the hydraulic cylinder for side shifting, etc.).

[0004] The present disclosure has been made to solve the above-mentioned problems, and an object thereof is to provide an industrial vehicle capable of suppressing an excessive load from being applied to a mechanism on the fork side during a lateral movement.

[0005] Solutions for solving problems

[0006] An industrial vehicle according to one aspect of the present disclosure is provided with a cargo handling device having a pair of forks, and cargo handling is performed by inserting the pair of forks into an insertion hole of a pallet. The industrial vehicle is provided with: a side shift mechanism that causes the position of the pair of forks to shift laterally in the horizontal direction; a distance sensor that is provided on the horizontal side surface of at least one of the pair of forks and detects the distance from the side surface to the detection object; and a control unit that controls the side shifting operation of the pair of forks performed by the side shift mechanism based on the detection result of the distance sensor. The control unit stores an initial value of the distance between the side surface of the fork and the inner wall surface that defines the insertion hole when the side shifting operation performed by the side shift mechanism starts, and stops the side shifting operation performed by the side shift mechanism when the distance between the side surface of the fork and the inner wall surface changes from the initial value during the execution of the side shifting operation performed by the side shift mechanism.

[0007] In the industrial vehicle, the stopping of the lateral movement performed by the lateral movement mechanism is determined based on the relationship between the distance between the side of the fork and the inner wall surface of the pallet and the initial value of the distance. During the lateral movement, from the start of the movement to the time when the pallet is abutted against the loaded pallet, the fork and the pallet are both displaced in the horizontal direction. Therefore, during the above period, the distance detected by the distance sensor does not change from the initial value. On the other hand, after the pallet is abutted against the loaded pallet, the distance detected by the distance sensor changes from the initial value because only the fork slides in the horizontal direction in the insertion hole. Therefore, when the lateral movement is performed, the slippage of the fork in the insertion hole can be quickly detected by stopping the lateral movement when the distance between the side of the fork and the inner wall surface of the pallet changes from the initial value. Thus, it is possible to prevent the friction force when the pallet slides on the fork or the reaction force of the force of the fork pressing the inner wall surface of the pallet after the pallet hits other pallets from being applied to the fork. As a result, it is possible to suppress an excessive load from being applied to the fork-side mechanism during the lateral movement.

[0008] Also can be, distance sensor is arranged on the side surface of each of a pair of forks in opposite directions mutually.In this case, can accurately detect the slippage of the fork inserted in the hole.

[0009] Alternatively, the control unit stops the lateral movement performed by the lateral movement mechanism when the distance detected by the distance sensor of one fork increases from an initial value and the distance detected by the distance sensor of the other fork decreases from an initial value. After the loaded pallet comes into contact with the loaded pallet, the loaded pallet slides in one horizontal direction in the insertion hole. At this time, as the pallet slides, the distance between the side surface of one fork and the inner wall surface of the pallet increases, and the distance between the side surface of the other fork and the inner wall surface of the pallet decreases. Therefore, by arranging the distance sensors on the respective side surfaces of a pair of forks in opposite directions to each other and stopping the lateral movement as described above, the slippage of the fork in the insertion hole can be detected with good accuracy.

[0010] Alternatively, the distance sensor may be composed of a first distance sensor located at the base end side of the fork and a second distance sensor located at the tip end side of the fork. In this case, the slippage of the fork inserted into the hole can be detected with good accuracy.

[0011] Alternatively, the control unit stops the lateral movement performed by the lateral movement mechanism when one of the distances detected by the first distance sensor and the second distance sensor changes from an initial value. In this case, by stopping the lateral movement as described above, the slippage of the fork inserted into the hole can be detected with greater accuracy.

[0012] Alternatively, the control unit stops the lateral movement performed by the lateral movement mechanism when the distances detected by the first distance sensor and the second distance sensor are both changed from the initial values. When inserting the fork into the insertion hole of the pallet, it is conceivable that the fork is inserted obliquely relative to the extension direction of the insertion hole. In this case, it is considered that a part of the pallet being loaded will first abut against the loaded pallet, and then the other part will abut against the loaded pallet. Therefore, according to the control as described above, when the fork is inserted obliquely relative to the extension direction of the insertion hole, the lateral movement can be stopped at the time when the pallet being loaded abuts against other loaded pallets. Therefore, while the pallet being loaded can be arranged without a gap relative to the loaded pallet, it is possible to prevent excessive load from being applied to the mechanism on the fork side during the lateral movement.

[0013] Alternatively, the control unit may stop the lateral movement by the lateral movement mechanism when a predetermined time has passed since one of the distances detected by the first distance sensor and the second distance sensor has changed from an initial value. According to such control, by setting the predetermined time in consideration of the speed of the lateral movement, it is possible to arrange the pallet being loaded with no gap relative to the pallet that has been loaded, while suppressing the application of an excessive load to the mechanism on the fork side during the lateral movement.

[0014] Alternatively, the control unit stops the lateral movement performed by the lateral movement mechanism when the distance detected by the first distance sensor and the distance detected by the second distance sensor become equal after one of the distances detected by the first distance sensor and the second distance sensor changes from the initial value. In the case where the fork is inserted obliquely relative to the extension direction in the insertion hole, as described above, a portion of the pallet being loaded first abuts against the loaded pallet. At this time, the distance detected by a distance sensor located near the portion changes from the initial value. Thereafter, the other portion abuts against the loaded pallet, so that the distances detected by the two distance sensors become equal. Therefore, according to the control as described above, in the case where the fork is inserted obliquely relative to the extension direction of the insertion hole, the lateral movement can be stopped at the time when the pallet being loaded abuts against other loaded pallets. Therefore, while the pallet being loaded can be arranged without gap relative to the loaded pallet, it is possible to suppress the excessive load applied to the mechanism on the fork side during the lateral movement.

[0015] Alternatively, the distance sensor may be disposed on the side of the fork facing the other side in a pair of forks. In this case, the distance sensor can be prevented from colliding with the inner wall surface of the pallet as the forks move sideways. Thus, damage to the distance sensor can be prevented.

[0016] Alternatively, a bracket with a window may be provided at a pair of forks, the bracket with a window being arranged on the side in such a manner that the distance sensor is exposed from the window. In this case, the protection of the distance sensor by the bracket can be achieved while easily realizing the configuration of arranging the distance sensor on the side.

[0017] Effects of the Invention

[0018] According to the present disclosure, it is possible to suppress an excessive load from being applied to the fork-side mechanism during the lateral movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a side view showing an example of an industrial vehicle of the present disclosure.

[0020] Figure 2 This is a perspective view schematically showing a situation when an industrial vehicle is loading and unloading cargo.

[0021] Figure 3 It is shown Figure 1 A block diagram of the functional composition of an industrial vehicle is shown.

[0022] Figure 4 It is a perspective view showing the structure of a fork.

[0023] Figure 5 It is a cross-sectional view schematically showing the configuration of a fork and a pallet.

[0024] Figure 6 It is a cross-sectional view schematically showing the configuration of a fork and a pallet.

[0025] Figure 7 This is a flowchart showing an example of the operation of the industrial vehicle.

[0026] Figure 8 1 is a flowchart showing an example of control of the lateral movement operation.

[0027] Fig. 9 It is a cross-sectional view schematically showing the configuration of a fork and a pallet.

[0028] Fig.10 It is a cross-sectional view schematically showing the configuration of a fork and a pallet.

[0029] Fig.11 2 is a flowchart showing another example of control of the lateral movement operation.

[0030] Fig.12 2 is a flowchart showing another example of control of the lateral movement operation. DETAILED DESCRIPTION

[0031] Hereinafter, preferred embodiments of an industrial vehicle according to one aspect of the present disclosure will be described in detail with reference to the accompanying drawings.

[0032] First, refer to Figure 1 The configuration of the industrial vehicle 1 according to the present disclosure will be described. Figure 1 1 is a side view showing an example of an industrial vehicle 1. Figure 1 As shown, the industrial vehicle 1 includes a travel device 2 and a cargo handling device 3 which is arranged in front of the travel device 2 and has a pair of forks 13 .

[0033] The travel device 2 includes a vehicle body 4, a pair of driving wheels, namely, front wheels 5, arranged at the front of the vehicle body 4, and a pair of steering wheels, namely, rear wheels 6, arranged at the rear of the vehicle body 4. A cab 7 composed of a frame including a head guard is provided on the vehicle body 4. A lifting operation lever for operating a lifting cylinder 14, a tilting operation lever for operating a tilting cylinder 15, a steering member for steering the industrial vehicle 1, and the like are arranged in the cab 7. In addition, the travel device 2 includes a travel motor for rotating the front wheels 5, and a steering motor for steering the rear wheels 6 by rotating a handle shaft of the industrial vehicle 1. In the industrial vehicle 1, the travel motor rotates the front wheels 5, and the steering motor steers the rear wheels 6, thereby realizing travel by the travel device 2.

[0034] The cargo handling device 3 includes a mast 11, a pair of forks 13, a lift cylinder 14, a tilt cylinder 15, and a side shift cylinder 16 (see Figure 3 ). The mast 11 is mounted on the vehicle body 4. A pair of forks 13 are mounted on the mast 11 via a lifting bracket 12 to hold the cargo W. The lifting cylinder 14 raises and lowers the forks 13. The tilt cylinder 15 tilts the mast 11. The side shift cylinder 16 shifts the forks 13 in the horizontal direction. In the present embodiment, the side shift cylinder 16 functions as a side shift mechanism that shifts the position of the pair of forks 13 in the horizontal direction.

[0035] The industrial vehicle 1 is an autonomous vehicle and receives a pallet P at a receiving position set at an arbitrary position indoors or outdoors, for example, and moves to a loading position where the pallet P is to be loaded. The industrial vehicle 1 then loads the pallet P at the loading position. Figure 2 It is a perspective view schematically showing the situation when the industrial vehicle 1 is loading and unloading cargo.

[0036] The pallet P is a cargo loading and unloading platform for loading cargo W, and is a cargo loading and unloading object for cargo loading and unloading by the cargo loading and unloading device 3. Figure 2 As shown, for example, one or more goods W are placed on a pallet P. The pallet P is a flat pallet made of plastic or wood, for example. The pallet P has a rectangular shape when viewed from above.

[0037] The pallet P has a front surface Pa, a rear surface Pb, and a pair of side surfaces Pc. The front surface Pa is a surface facing the industrial vehicle 1 when the pallet P is held by the fork 13. The rear surface Pb is a surface located on the side opposite to the front surface Pa. The pair of side surfaces Pc are surfaces that abut against a loaded pallet or the like when the pallet P is loaded.

[0038] The pallet P is provided with an insertion hole H into which the pair of forks 13 are inserted. In the present embodiment, the pallet P is provided with a pair of insertion holes H corresponding to the pair of forks 13. The insertion holes H are through holes having a rectangular cross section that penetrate from the front surface Pa to the rear surface Pb of the pallet P. The insertion holes H are defined by the inner wall surface Pd of the pallet P.

[0039] In the following description, the pallet to be loaded next by the industrial vehicle 1 is referred to as "pallet P1", and the pallet that has been loaded is referred to as "pallet P2". Here, for convenience, the pallet P1 and the pallet P2 are described as having the same structure.

[0040] When loading and unloading cargo, the industrial vehicle 1 holds the pallet P1 by inserting a pair of forks 13 into the insertion hole H. At this time, in the insertion hole H, the side 13a of the fork 13 and the inner wall surface Pd defining the insertion hole H are opposite to each other in the horizontal direction. When loading the pallet P1, the pair of forks 13 are automatically shifted sideways by the side shift cylinder 16, so that the pallet P1 is brought into contact with the loaded pallet P2, and loading is performed in a manner that no gap is generated between the two. At this time, when the side shift amount of the pair of forks 13 becomes excessive, it is considered that the loaded pallet P1 may hit the pallet P2. In this case, there is the possibility that the friction force when the pallet P1 slides on the fork 13, or the reaction force of the force pressing the inner wall surface Pd of the pallet P1 defining the insertion hole H after the pallet P1 hits the pallet P2 is applied to the fork 13, and a load is applied to the mechanism on the fork 13 side.

[0041] In order to solve such a problem, the industrial vehicle 1 quickly detects the slippage of the pallet P1 during the sideways movement to prevent the friction force when the pallet P1 slides on the fork 13 or the reaction force of the fork 13 pressing the inner wall surface Pd of the pallet P1 after the pallet P1 hits the pallet P2 from being applied to the fork 13. In order to realize this function, the industrial vehicle 1 includes a control device 20.

[0042] Hereinafter, the functional configuration of the control device 20 for realizing this function will be described in detail. Figure 3 2 is a block diagram showing an example of the functional configuration of an industrial vehicle. In order to realize the above-mentioned functions, the control device 20 includes a first distance sensor 21 , a second distance sensor 22 , and a control unit 23 .

[0043] The first distance sensor 21 and the second distance sensor 22 are distance sensors that detect the distance from the sensor itself to the detection object located in front of the sensor. For example, the first distance sensor 21 and the second distance sensor 22 detect the distance between themselves and the detection object by irradiating a laser in front of themselves and receiving the reflected light of the laser from the detection object.

[0044] The first distance sensor 21 and the second distance sensor 22 are disposed on the horizontal side surfaces 13a of the pair of forks 13. Figure 4 As shown, in each of the pair of forks 13, the first distance sensor 21 is provided at the base end side of the fork 13, and the second distance sensor 22 is provided at the top end side of the fork. That is, in the present embodiment, the first distance sensor 21 and the second distance sensor 22 are provided at mutually different positions on the side surface 13a in the extending direction of the fork 13. On the side surface 13a, the first distance sensor 21 and the second distance sensor 22 may be provided in a manner of being embedded in the side surface 13a, or may be provided on the side surface 13a.

[0045] The first distance sensor 21 and the second distance sensor 22 are disposed on the side surfaces 13a of the forks 13 in a pair of forks 13 facing each other in opposite directions. The first distance sensor 21 and the second distance sensor 22 disposed on one fork 13 are horizontally opposed to the first distance sensor 22 disposed on the other fork.

[0046] Furthermore, in this embodiment, if Figure 4 As shown, a bracket B with a window is provided on each side 13a of a pair of forks 13. Two windows Ba are provided on the bracket B. The window Ba is provided, for example, at an opening of the bracket B. In the bracket B, the two windows Ba are provided at positions corresponding to positions where the first distance sensor 21 and the second distance sensor 22 are provided. That is, the bracket B with a window is provided on the side 13a of the fork 13 in such a manner that the first distance sensor 21 and the second distance sensor 22 are exposed from the corresponding windows Ba.

[0047] For example, when the pair of forks 13 are inserted into the insertion hole H of the pallet P1, the side surfaces of the forks 13 are opposite to the inner wall surface Pd defining the insertion hole H. Therefore, in this state, the detection object is the inner wall surface Pd of the pallet P1, and the first distance sensor 21 and the second distance sensor 22 detect the distance from the side surface 13a of the forks 13 to the inner wall surface Pd.

[0048] The control unit 23 is a part that controls the lateral movement performed by the lateral movement cylinder 16 (lateral movement mechanism). In the present embodiment, in order to control the movement, the control unit 23 implements the storage of the initial value ds and the start and stop of the lateral movement. The storage of the initial value ds and the control of the start and stop of the lateral movement as the processing performed by the control unit 23 are described in detail below.

[0049] First, the storage of the initial value ds is described. The initial value ds is the distance between the side surface 13a and the inner wall surface Pd when the lateral movement performed by the lateral movement cylinder 16 starts. In one example, the control unit 23 stores the distances d1 and d2 received from the first distance sensor 21 and the second distance sensor 22 at the start of the lateral movement as the initial value ds. In this case, the control unit 23 may store the respective distances received from the first distance sensor 21 and the second distance sensor 22 as the corresponding initial value ds at the start of the lateral movement, or may store any one of the distances as the initial value ds. Alternatively, the control unit 23 may store the value pre-entered by the user using the industrial vehicle 1 as the initial value ds.

[0050] Next, the control of starting and stopping the lateral movement will be described. In the present embodiment, the start of the lateral movement is controlled by sending a start command to the lateral movement cylinder 16, and the stop of the lateral movement is controlled by sending a stop command to the lateral movement cylinder 16. The start command is a command for starting the lateral movement, and the stop command is a command for stopping the lateral movement. In one example, the control unit 23 stops the lateral movement performed by the lateral movement cylinder 16 based on the relationship between the distances d1 and d2 during the lateral movement and the initial value ds.

[0051] In the present embodiment, the control of the control unit 23 to stop the lateral movement is performed, for example, when the fork 13 is inserted in a manner along the extending direction of the insertion hole H. Here, before describing a more specific process for stopping the lateral movement, first refer to Figure 5 and Figure 6 The configuration of the fork 13 and the pallet P1 during the lateral movement in the above-mentioned case will be described in detail.

[0052] Figure 5 and Figure 6 is a cross-sectional view schematically showing the structure of a fork and a pallet. Specifically, Figure 5 It is a cross-sectional view schematically showing the configuration of the fork 13 and the pallet P1 at the start of the sideways movement operation. Figure 6 1 is a cross-sectional view schematically showing the structure of the fork 13 and the pallet P1 when the pallet P1 abuts against the pallet P2. Figure 5 and Figure 6 In the figure, the structure of the fork 13 is simplified, but in fact it is the same as Figure 4 The configuration shown is the same configuration.

[0053] First, the distance between the inner wall surface Pd at each position of the side surface 13a will be described. When the fork 13 is inserted along the extending direction of the insertion hole H as described above, the distance between the inner wall surface Pd at any position of the side surface 13a is the same.

[0054] Next, the change in the distance between the side surface 13a and the inner wall surface Pd during the side movement operation is described. During the side movement operation, the fork 13 and the pallet P1 are both displaced in the horizontal direction from the time when the side movement operation starts to the time when the pallet P1 held by the fork 13 abuts against the pallet P2. Figure 5 As shown, the distance between the side surface 13a of the fork 13 and the inner wall surface Pd does not change from the distance at the beginning of the side movement.

[0055] On the other hand, after the pallet P1 held by the fork 13 comes into contact with the pallet P2, only the fork 13 slides in the horizontal direction in the insertion hole H. Specifically, Figure 6 As shown, the fork 13 slides toward the side surface Pc abutting against the pallet P2 in the insertion hole H. As a result, in one fork 13 located on the side surface Pc, the distance between the side surface 13a and the inner wall surface Pd increases, and in the other fork 13, the distance between the side surface 13a and the inner wall surface Pd decreases.

[0056] According to the above, when the fork 13 is inserted in a manner along the extension direction of the insertion hole H, during the period from the start of the lateral movement to the abutment of the pallet P1 against the pallet P2, the distances d1 and d2 detected by the first distance sensor 21 and the second distance sensor 22 of each fork 13 provided in a pair of forks 13 are equal to each other.

[0057] Similarly, after pallet P1 abuts pallet P2, distance d1 detected by first distance sensor 21 and distance d2 detected by second distance sensor 22 in one fork 13 on the side abutting pallet P2 increase from initial value ds, while distance d1 and distance d2 in the other fork 13 decrease from initial value ds.

[0058] In the present embodiment, the side movement operation by the control unit 23 is stopped in view of the change in the distance between the side surface 13a of the fork 13 and the inner wall surface Pd during the above-mentioned side movement operation. That is, in the present embodiment, the control unit 23 stops the side movement operation by the side movement cylinder 16 when the distance d1 and the distance d2 in the fork 13 on the side surface Pc of the pallet P1 that contacts the pallet P2 increase from the initial value ds and the distance d1 and the distance d2 in the other fork 13 decrease from the initial value ds.

[0059] Alternatively, the control unit 23 may stop the lateral movement performed by the side shift cylinder 16 when the distance d1 or the distance d2 in the fork 13 on the side Pc of the pallet P1 abutting against the pallet P2 increases from the initial value ds and the distance d1 or the distance d2 in the other fork 13 decreases from the initial value ds.

[0060] As described above, the first distance sensor 21 and the second distance sensor 22 are provided on the side surface 13a of the fork 13. The detection object of the first distance sensor 21 and the second distance sensor 22 is the inner wall surface Pd defining the insertion hole H. Therefore, the distances d1 and d2 detected by the first distance sensor 21 and the second distance sensor 22 are the distances between the side surface 13a and the inner wall surface Pd of the fork 13. Based on the above, the control unit 23 stops the side shifting operation performed by the side shift cylinder 16 when the distance between the side surface 13a and the inner wall surface Pd of one fork 13 becomes larger than the initial value ds and the distance between the side surface 13a and the inner wall surface Pd of the other fork 13 becomes smaller than the initial value ds.

[0061] Next, refer to Figure 7 An example of the operation of the industrial vehicle 1 will be described. Figure 7 This is a flowchart showing an example of the operation of the industrial vehicle 1 .

[0062] In step S1, the fork 13 is inserted into the insertion hole H of the pallet P1. Thus, the pallet P1 is held by the fork 13. In step S2, the control unit 23 adjusts the fork position in the insertion hole H. Here, the fork position in the insertion hole H is adjusted based on the width of the fork 13 and the width of the insertion hole H so that the first distance sensor 21 and the second distance sensor 22 do not contact the inner wall surface Pd of the pallet P1 during the sideways movement during loading.

[0063] In step S3, the first distance sensor 21 and the second distance sensor 22 provided in each of the pair of forks 13 detect the distance (initial value ds) between the side surface 13a of the fork 13 and the inner wall surface Pd when the side movement operation starts.

[0064] In step S4, the control unit 23 controls the lateral movement operation performed by the lateral movement cylinder 16. Figure 8 The control of the lateral movement by the control unit 23 in step S4 will be described in further detail. Figure 8 1 is a flowchart showing an example of control of the lateral movement operation.

[0065] In step S401, the control unit 23 starts the side shift operation by the side shift cylinder 16. Here, the control unit 23 starts the side shift operation by transmitting a start command to the side shift cylinder 16 to start the side shift operation.

[0066] In step S402 , the first distance sensor 21 and the second distance sensor 22 provided at each fork 13 of the pair of forks 13 detect the distances d1 , d2 between the side surface 13 a of the fork 13 and the inner wall surface Pd.

[0067] In step S403, the control unit 23 determines whether the distances d1 and d2 between the side surface 13a and the inner wall surface Pd of the fork 13 detected in step S402 have changed from the initial value ds. Here, the control unit 23 determines whether the distances d1 and d2 in one fork 13 have increased from the initial value ds, and whether the distances d1 and d2 in the other fork 13 have decreased from the initial value ds.

[0068] When the distance d1 and the distance d2 in one fork 13 are increased from the initial value ds, and the distance d1 and the distance d2 in the other fork 13 are decreased from the initial value ds (YES in step S403 ), the process proceeds to step S404 .

[0069] If the distance d1 and the distance d2 in one fork 13 do not increase from the initial value ds, or if the distance d1 and the distance d2 in the other fork 13 do not decrease from the initial value ds (NO in step S403 ), the process returns to step S402 .

[0070] In step S404, the control unit 23 stops the side movement operation by the side movement cylinder 16. Here, the control unit 23 stops the side movement operation by sending a stop command to the side movement cylinder 16 to stop the side movement operation.

[0071] As described above, in the industrial vehicle 1, the stopping of the lateral movement performed by the lateral movement cylinder 16 (lateral movement mechanism) is determined based on the relationship between the distances d1 and d2 between the side surface 13a of the fork 13 and the inner wall surface Pd of the pallet P1 and the initial value ds of the distances. During the lateral movement, from the start of the movement to the time when the pallet P1 and the loaded pallet P2 come into contact, both the fork 13 and the pallet P1 are displaced in the horizontal direction. Therefore, during the above period, the distances d1 and d2 detected by the first distance sensor 21 and the second distance sensor 22 do not change from the initial value ds. On the other hand, after the pallet P1 comes into contact with the loaded pallet P2, since only the fork 13 slides in the horizontal direction in the insertion hole H, the distances d1 and d2 detected by the first distance sensor 21 and the second distance sensor 22 change from the initial value ds. Therefore, when the sideways movement is performed, the sideways movement is stopped when the distances d1 and d2 between the side surface 13a of the fork 13 and the inner wall surface Pd of the pallet P1 change from the initial value ds, so that the slippage of the fork 13 inserted into the hole H can be detected quickly. As a result, the friction force when the pallet P1 slides on the fork 13 or the reaction force of the fork 13 pressing the inner wall surface Pd of the pallet P1 after the pallet P1 hits the pallet P2 can be prevented from being applied to the fork 13. As a result, it is possible to suppress the excessive load on the mechanism on the fork 13 side during the sideways movement.

[0072] In the industrial vehicle 1, by stopping the lateral movement by the above-mentioned control, it is possible to prevent the lateral movement from becoming excessive. As a result, the time required for the lateral movement when loading one pallet P1 can be reduced compared to the conventional loading. As a result, the time required for the cargo loading and unloading operation by the industrial vehicle 1 can be reduced.

[0073] In the industrial vehicle 1, the first distance sensor 21 and the second distance sensor 22 are provided on the side surfaces 13a of the pair of forks 13 in opposite directions to each other. In this case, the detection accuracy of the slippage of the forks 13 inserted into the holes H can be improved.

[0074] In the industrial vehicle 1, the control unit 23 stops the side shifting operation by the side shift cylinder 16 when the distance d1 and the distance d2 in one fork 13 increase from the initial value ds and the distance d1 and the distance d2 in the other fork 13 decrease from the initial value ds. After the pallet P1 being loaded abuts against the pallet P2 that has been loaded, the pallet P1 being loaded slides in one horizontal direction in the insertion hole H. At this time, as the fork 13 slides, the distance between the side surface 13a of one fork 13 and the inner wall surface Pd of the pallet P increases, and the distance between the side surface 13a of the other fork 13 and the inner wall surface Pd of the pallet P decreases. Therefore, by providing the first distance sensor 21 and the second distance sensor 22 on the side surfaces 13a of the pair of forks 13 in opposite directions to each other and stopping the side shifting operation as described above, the slippage of the fork 13 in the insertion hole H can be detected with good accuracy.

[0075] In the industrial vehicle 1, the control device 20 includes a first distance sensor 21 located at the base end side of the fork 13 and a second distance sensor 22 located at the tip end side of the fork. In this case, the slippage of the fork 13 inserted into the hole H can be detected with high accuracy.

[0076] In the industrial vehicle 1, the first distance sensor 21 and the second distance sensor 22 are provided on the side surface 13a of the fork 13 facing the other side in the pair of forks 13. In this case, the first distance sensor 21 and the second distance sensor 22 can be prevented from colliding with the inner wall surface Pd of the pallet P1 during the sideways movement. Therefore, damage to the first distance sensor 21 and the second distance sensor 22 can be prevented.

[0077] In the industrial vehicle 1, a bracket B with a window is provided on the pair of forks 13. The bracket B with a window is provided on the side surface 13a so that the first distance sensor 21 and the second distance sensor 22 are exposed from the window Ba. In this case, while the configuration of providing the first distance sensor 21 and the second distance sensor 22 on the side surface 13a is easily realized, the bracket B can protect the first distance sensor 21 and the second distance sensor 22.

[0078] Next, refer to Fig. 9 and Fig.10 A modification of the control of the lateral movement by the control unit 23 will be described. Fig. 9 and Fig.10 is a cross-sectional view showing the structure of a fork and a pallet. Specifically, Fig. 9 It is a cross-sectional view showing the configuration of the fork 13 and the pallet P1 at the start of the sideways movement. Fig.10 1 is a cross-sectional view showing the structure of the fork 13 and the pallet P1 when the pallet P1 and the pallet P2 abut against each other. Fig. 9 and Fig.10 In the figure, the structure of the fork 13 is also simplified, but in fact it is the same as Figure 4 The configuration shown is the same configuration.

[0079] In this modification, the control of the sideways movement by the control unit 23 is performed, for example, when the fork 13 is inserted obliquely with respect to the extending direction of the insertion hole H. Here, before describing the specific processing of the control unit 23 in this modification, the configuration of the fork 13 and the pallet P1 during the sideways movement when the fork 13 is inserted obliquely with respect to the extending direction of the insertion hole H will be described in detail.

[0080] First, the distance between the side surface 13a and the inner wall surface Pd at each position will be described. When the fork 13 is inserted obliquely with respect to the extending direction of the insertion hole H, the distance between the side surface 13a and the inner wall surface Pd is not equal on the entire side surface 13a. That is, in the side surface 13a, the distance from the inner wall surface Pd is different for each position on the side surface 13a.

[0081] For example, in Fig. 9 In the example shown, one fork 13 has a smaller distance from the inner wall surface Pd as it approaches the base end, and the other fork 13 has a larger distance from the inner wall surface Pd as it approaches the base end. In the following description, in order to distinguish between a pair of forks 13, the fork 13 in which the distance between the side surface 13a and the inner wall surface Pd decreases as it approaches the base end is referred to as "fork 13A", and the fork 13 in which the distance between the side surface 13a and the inner wall surface Pd increases as it approaches the base end is referred to as "fork 13B".

[0082] Next, the change in the distance between the side surface 13a and the inner wall surface Pd during the sideways movement will be described. Fig. 9 As shown in FIG. 1 , even when the forks 13A and 13B are inserted obliquely with respect to the extending direction of the insertion hole H, the forks 13A and 13B and the pallet P1 are both displaced in the horizontal direction from the time point when the side movement operation starts to the time when the pallet P1 held by the forks 13A and 13B abuts against the loaded pallet P2. Therefore, during the above period, similarly to the case where the forks 13 are inserted along the extending direction of the insertion hole H, the distance between each side surface 13a of the forks 13A and 13B and the inner wall surface Pd does not change from the initial value ds.

[0083] On the other hand, when the pallet P1 contacts the pallet P2, a portion of the pallet P1 contacts the pallet P2 first. Specifically, a portion of the side surface Pc of the pallet P1 contacts the pallet P2. At this time, the distance between the portion of the side surface 13a of each of the forks 13A and 13B close to the side surface Pc and the inner wall surface Pd changes from the distance at the start of the side movement. Fig.10As shown in FIG. 1 , the pallet P1 is displaced so as to fill the gap between the remaining portion of the side surface Pc of the pallet P1 and the pallet P2. After the entire side surface Pc of the pallet P1 abuts against the pallet P2, the distance between the remaining portion of each side surface 13a of the forks 13A and 13B and the inner wall surface Pd changes from the distance at the start of the side movement, and the distance between the side surface 13a and the inner wall surface Pd becomes equal over the entire side surface 13a.

[0084] As described above, when the forks 13A and 13B are inserted obliquely with respect to the extending direction of the insertion hole H, the distances d1 and d2 detected by the first distance sensor 21 and the second distance sensor 22 provided at the pair of forks 13A and 13B are different from each other. The initial value ds is also different from each other depending on the position of each distance sensor.

[0085] In the following description, in order to distinguish the distances d1 , the distance d1 detected by the first distance sensor 21 provided at the fork 13A is referred to as “distance d1A”, and the distance d1 detected by the first distance sensor 21 provided at the fork 13B is referred to as “distance d1B”.

[0086] In order to distinguish the distances d2, the distance d2 detected by the second distance sensor 22 provided at the fork 13A is referred to as "distance d2A", and the distance d2 detected by the second distance sensor 22 provided at the fork 13B is referred to as "distance d2B".

[0087] In order to distinguish each initial value ds, the initial value ds at the position where the first distance sensor 21 and the second distance sensor 22 are set in the fork 13A are respectively referred to as "initial value ds1" and "initial value ds2", and the initial value ds at the position where the first distance sensor 21 and the second distance sensor 22 are set in the fork 13B are respectively referred to as "initial value ds3" and "initial value ds4".

[0088] In the fork 13A, since a part of the pallet P1 contacts the pallet P2, one of the distances d1A and d2A changes from the corresponding initial values ​​ds1 and ds2, and then since the remaining part of the pallet P1 contacts the pallet P2, the other of the distances d1A and d2A changes from the corresponding initial values ​​ds1 and ds2, and finally, the distance d1A and the distance d2A become equal. In the fork 13B, the distances d1B and d2B also change in the same way as the fork 13A.

[0089] In this modification, the control unit 23 controls the lateral movement in consideration of the change in the distance between the side surface 13a of the forks 13A and 13B and the inner wall surface Pd when the forks 13A and 13B are inserted obliquely with respect to the extending direction of the insertion hole H.

[0090] Specifically, the control unit 23 stops the side shifting operation by the side shift cylinder 16 when a predetermined time has passed since one of the distances d1A and d2A changes from the corresponding initial values ​​ds1 and ds2 and one of the distances d1B and d2B changes from the corresponding initial values ​​ds3 and ds4.

[0091] Alternatively, the control unit 23 may stop the lateral movement performed by the lateral movement cylinder 16 when a specified time has passed after one of the distances d1A and d2A has changed from the corresponding initial values ​​ds1 and ds2, or when a specified time has passed after one of the distances d1B and d2B has changed from the corresponding initial values ​​ds3 and ds4.

[0092] The above-mentioned prescribed time is determined based on the speed of the fork 13 that is shifted according to the speed of the lateral movement. The above-mentioned prescribed time is set in consideration of the speed of the lateral movement, and its range is, for example, not less than 0.5 seconds and not more than 3.0 seconds. By setting the above-mentioned prescribed time to not less than 0.5 seconds, the gap between pallet P1 and pallet P2 can be made infinitely close to zero. In addition, during the lateral movement, when the lateral displacement in the action becomes the maximum, sometimes the loading of pallet P1 will start even when pallet P1 and pallet P2 are not in contact. In such a case, by setting the above-mentioned prescribed time to not more than 3.0 seconds, the lateral movement can be stopped before the lateral displacement becomes the maximum, thereby preventing the loading of pallet P1 when pallet P1 and pallet P2 are not in contact.

[0093] The speed of the sideways movement includes, for example, the displacement speed of the fork 13 during the sideways movement. Therefore, the predetermined time may be set in consideration of the displacement speed of the fork 13 during the sideways movement.

[0094] Next, refer to Fig.11 The control of the lateral movement by the control unit 23 in step S4 of this modification example will be described. Fig.11 2 is a flowchart showing another example of control of the lateral movement operation.

[0095] In step S411, similarly to step S401, the control unit 23 starts the side shift operation by the side shift cylinder 16. In step S412, the first distance sensor 21 and the second distance sensor 22 provided at each of the pair of forks 13A and 13B detect the distances d1A, d1B, d2A, and d2B between the side surface 13a of the fork 13 and the inner wall surface Pd.

[0096] In step S413 , the control unit 23 determines whether one of the distances d1A and d2A has changed from the corresponding initial values ​​ds1 and ds2 , and whether one of the distances d1B and d2B has changed from the corresponding initial values ​​ds3 and ds4 .

[0097] When one of the distances d1A and d2A has changed from the corresponding initial values ​​ds1 and ds2, and one of the distances d1B and d2B has changed from the corresponding initial values ​​ds3 and ds4 (YES in step S413), the process proceeds to step S414.

[0098] If one of the distances d1A and d2A has not changed from the corresponding initial values ​​ds1 and ds2, or if one of the distances d1B and d2B has not changed from the corresponding initial values ​​ds3 and ds4 (NO in step S413), the process returns to step S412.

[0099] In step S414 , the control unit 23 determines whether a predetermined time has elapsed since one of the distances d1A and d2A changed from the corresponding initial value ds1 or ds2 and one of the distances d1B and d2B changed from the corresponding initial value ds3 or ds4 .

[0100] If the predetermined time has passed ("Yes" in step S414), the process proceeds to step S415. If the predetermined time has not passed ("No" in step S414), the process returns to step S414. That is, in this modification, the control unit 23 does not advance the process until the predetermined time has passed after one of the distances d1A and d2A has changed from the corresponding initial values ​​ds1 and ds2, and one of the distances d1B and d2B has changed from the corresponding initial values ​​ds3 and ds4.

[0101] In step S415 , similarly to step S404 , the control unit 23 stops the side shifting operation performed by the side shift cylinder 16 .

[0102] In this modification, the control unit 23 stops the lateral movement operation by the lateral movement cylinder 16 when a predetermined time has passed since one of the distances d1A and d2A has changed from the corresponding initial values ​​ds1 and ds2, and one of the distances d1B and d2B has changed from the corresponding initial values ​​ds3 and ds4. According to such control, by setting the predetermined time in consideration of the speed of the lateral movement operation, it is possible to arrange the pallet P1 with respect to the pallet P2 without a gap, while suppressing the application of an excessive load to the mechanism on the fork 13 side during the lateral movement operation.

[0103] Next, another modification of the control of the lateral movement by the control unit 23 will be described. The control of the lateral movement by the control unit 23 in this modification is also performed when the forks 13A and 13B are inserted obliquely with respect to the extending direction of the insertion hole H, for example.

[0104] In this case, as described above, in fork 13A, since part of pallet P1 abuts against pallet P2, one of distances d1A and d2A changes from the corresponding initial values ​​ds1 and ds2. Then, since the remaining part of pallet P1 abuts against pallet P2, the other of distances d1A and d2A changes from the corresponding initial values ​​ds1 and ds2. Finally, distance d1A and distance d2A become equal. The same is true for fork 13B as for fork 13A.

[0105] Therefore, in this modification, the control unit 23 stops the side shifting operation by the side shift cylinder 16 when one of the distances d1A and d2A changes from the corresponding initial values ​​ds1 and ds2, and when one of the distances d1B and d2B changes from the corresponding initial values ​​ds3 and ds4, and when the distances d1A and d2A become equal and the distances d1B and d2B become equal. Here, "equal" does not necessarily mean that the values ​​are identical. Even when the values ​​include a slight difference or a measurement error within a preset range, they can be regarded as "equal".

[0106] Next, refer to Fig.12 The control of the lateral movement by the control unit 23 in step S4 of this modification example will be described. Fig.12 2 is a flowchart showing another example of control of the lateral movement operation.

[0107] In step S421, similarly to step S401, the control unit 23 starts the side shift operation by the side shift cylinder 16. In step S422, similarly to step S412, the first distance sensor 21 and the second distance sensor 22 provided at each of the pair of forks 13A and 13B detect the distances d1A, d1B, d2A, and d2B between the side surface 13a of the fork 13 and the inner wall surface Pd.

[0108] In step S423 , the control unit 23 determines whether one of the distances d1A and d2A has changed from the corresponding initial values ​​ds1 and ds2 , and whether one of the distances d1B and d2B has changed from the corresponding initial values ​​ds3 and ds4 .

[0109] When one of the distances d1A and d2A has changed from the corresponding initial values ​​ds1 and ds2, and one of the distances d1B and d2B has changed from the corresponding initial values ​​ds3 and ds4 (YES in step S423), the process proceeds to step S424.

[0110] When one of the distances d1A and d2A has not changed from the corresponding initial values ​​ds1 and ds2, or when one of the distances d1B and d2B has not changed from the corresponding initial values ​​ds3 and ds4 (NO in step S423), the process returns to step S422.

[0111] In step S424, similarly to step S422, the first distance sensor 21 and the second distance sensor 22 provided at each of the pair of forks 13A and 13B detect the distances d1A, d1B, d2A, and d2B between the side surface 13a of the fork 13 and the inner wall surface Pd.

[0112] In step S425, the control unit 23 determines whether the distance d1A is equal to the distance d2A and whether the distance d1B is equal to the distance d2B. If the distance d1A is equal to the distance d2A and the distance d1B is equal to the distance d2B ("Yes" in step S425), the process proceeds to step S426. If the distance d1A is not equal to the distance d2A or the distance d1B is not equal to the distance d2B ("No" in step S425), the process returns to step S424.

[0113] In step S426 , similarly to step S404 , the control unit 23 stops the side shifting operation performed by the side shift cylinder 16 .

[0114] In this modification, the control unit 23 stops the side shifting operation by the side shift cylinder 16 when one of the distances d1A and d2A changes from the corresponding initial values ​​ds1 and ds2, and when one of the distances d1B and d2B changes from the corresponding initial values ​​ds3 and ds4, so that the distances d1A and d2A become equal, and the distances d1B and d2B become equal. When the fork 13 is inserted obliquely with respect to the extending direction in the insertion hole H, as described above, a part of the pallet P1 being loaded first abuts against the pallet P2 that has been loaded. At this time, the distance detected by one of the distances d1A and d1B and the distances d2A and d2B that is located near the above-mentioned part changes from the corresponding initial values ​​ds1 to ds4. Thereafter, because the other part of the pallet P1 abuts against the pallet P2, the distances d1A and d2A become equal, and the distances d1B and d2B become equal. Therefore, according to the control as described above, when the fork 13 is inserted obliquely with respect to the extending direction of the insertion hole H, the side movement operation can be stopped at the time when the pallet P1 abuts against the pallet P2. Therefore, while the pallet P1 can be arranged with no gap relative to the pallet P2, it is possible to suppress the excessive load on the mechanism on the fork side during the side movement operation.

[0115] As mentioned above, although embodiment and each modification of this disclosure were described, this disclosure is not necessarily limited to the above-mentioned embodiment and each modification, Various changes can be made within the range which does not deviate from the summary.

[0116] The control for stopping the lateral movement by the lateral movement cylinder 16 is not limited to the control described above. For example, the control unit 23 may stop the lateral movement by the lateral movement cylinder 16 when one of the distances d1 and d2 detected by the first distance sensor 21 and the second distance sensor 22 provided in each of the pair of forks 13 changes from the initial value ds. In this case, by stopping the lateral movement as described above, the slippage of the fork 13 inserted into the hole H can be detected with greater accuracy.

[0117] Alternatively, the side shifting operation by the side shift cylinder 16 may be stopped when both the distances d1 and d2 detected by the first distance sensor 21 and the second distance sensor 22 provided in each of the pair of forks 13 change from the initial value ds. In this case, the pallet P1 being loaded can be arranged without gap relative to the pallet P2 that has been loaded, while suppressing the excessive load on the mechanism on the side of the fork 13 during the side shifting operation.

[0118] In the above-mentioned embodiment and each modified example, the first distance sensor 21 and the second distance sensor 22 are provided on each of the pair of forks 13, but the first distance sensor 21 and the second distance sensor 22 may be provided on only one of the pair of forks 13. In this case, when one of the distances d1 and d2 detected by the first distance sensor 21 and the second distance sensor 22 provided on the one fork 13 changes from the initial value ds, the control unit 23 may stop the side movement operation performed by the side shift cylinder 16. Alternatively, when both the distances d1 and d2 detected by the first distance sensor 21 and the second distance sensor 22 provided on the one fork 13 change from the initial value ds, the control unit 23 may stop the side movement operation performed by the side shift cylinder 16.

[0119] In the above-mentioned embodiment and each modified example, the first distance sensor 21 and the second distance sensor 22 are provided in each of the pair of forks 13, but only one distance sensor may be provided in each of the pair of forks 13. In this case, when the distance detected by the one distance sensor provided in one fork 13 becomes larger than the initial value ds, and the distance detected by the one distance sensor provided in the other fork 13 becomes smaller than the initial value ds, the control unit 23 stops the side shifting operation performed by the side shift cylinder 16.

[0120] Alternatively, one distance sensor may be provided only on one fork 13 of the pair of forks 13. In this case, when the distance detected by the one distance sensor changes from the initial value ds, the control unit 23 may stop the side shifting operation performed by the side shift cylinder 16.

Claims

1. An industrial vehicle having a cargo handling device having a pair of forks, wherein cargo handling is performed by inserting the pair of forks into insertion holes of a pallet, wherein the industrial vehicle is characterized in that: A side shift mechanism that causes the position of the pair of forks to shift sideways in a horizontal direction; a distance sensor provided on a side surface of at least one of the pair of forks in the horizontal direction, and detecting a distance from the side surface to a detection object; and a control unit that controls the lateral movement of the pair of forks by the lateral movement mechanism based on the detection result of the distance sensor, The control unit storing an initial value of the distance between the side surface of the fork and the inner wall surface defining the insertion hole when the side shifting action performed by the side shifting mechanism starts, When the distance between the side surface of the fork and the inner wall surface changes from the initial value during the side shifting operation by the side shifting mechanism, the side shifting operation by the side shifting mechanism is stopped.

2. The industrial vehicle according to claim 1, wherein: The distance sensors are disposed on respective sides of the pair of forks in opposite directions from each other.

3. The industrial vehicle according to claim 2, wherein: The control unit stops the side shifting operation performed by the side shifting mechanism when the distance detected by the distance sensor of one fork increases from the initial value and the distance detected by the distance sensor of the other fork decreases from the initial value.

4. An industrial vehicle according to any one of claims 1 to 3, wherein: The distance sensor is composed of a first distance sensor located on the base end side of the fork and a second distance sensor located on the tip end side of the fork.

5. The industrial vehicle according to claim 4, wherein: The control unit stops the side shifting operation performed by the side shifting mechanism when one of the distances detected by the first distance sensor and the second distance sensor changes from the initial value.

6. The industrial vehicle according to claim 4, wherein: The control unit stops the side shifting operation performed by the side shifting mechanism when both the distances detected by the first distance sensor and the second distance sensor are changed from the initial values.

7. The industrial vehicle according to claim 4, wherein: The control unit stops the side shifting operation performed by the side shifting mechanism when a predetermined time has elapsed since one of the distances detected by the first distance sensor and the second distance sensor has changed from the initial value.

8. The industrial vehicle according to claim 4, wherein: The control unit stops the side shifting operation by the side shifting mechanism when the distance detected by the first distance sensor and the distance detected by the second distance sensor become equal after one of the distances detected by the first distance sensor and the second distance sensor changes from the initial value.

9. An industrial vehicle according to any one of claims 1 to 8, wherein: The distance sensor is provided on a side surface of the fork of the pair of forks that faces the other side.

10. An industrial vehicle according to any one of claims 1 to 9, wherein: A bracket with a window is provided on the pair of forks, The bracket with the window is disposed on the side surface in such a manner that the distance sensor is exposed from the window.

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