Pallet stacking and unstacking device

Abstract

Provided is a pallet stacking and unstacking device capable of stacking and unstacking pallets and compatible with both an automated guided vehicle and a hand lift. A pallet stacking and unstacking device 1 of the present invention comprises: supports 4 extending in a vertical direction from a floor surface G on which an automated guided vehicle V and a hand cart L for carrying a pallet P travel; pallet support claws 8 that ascend / descend along the supports 4 and support the pallet P; and a controller 10 that controls the ascending / descending operation of the pallet support claws 8. The controller 10 recognizes whether the recipient of the pallet P is the automated guided vehicle V or the hand cart L, and changes operation height positions of the pallet support claws 8 in accordance with whether the recipient of the pallet P is the automated guided vehicle V or the hand cart L on the basis of the recognition.

Description

Pallet stacking and unstacking device

[0001] The present invention relates to a pallet stacking and unstacking device, and particularly to a pallet stacking and unstacking device for stacking or unstacking pallets.

[0002] Conventionally, a transfer device including a lifting unit, a cart unit, and a conveyor unit is known (Patent Document 1). In this transfer device, after lifting the pallet received from the forklift to an upper position by the lifting unit, a cart is moved below it, and then the pallet is lowered from the lifting unit and transferred onto the cart below it. Finally, the goods are transferred from the cart to the conveyor. Also, within a predetermined work area of a warehouse, pallets and the goods placed on the pallets are transported using an automated guided vehicle that automatically travels upon receiving a command by wireless communication, or a forklift (so-called pallet truck, etc.) operated by an operator himself.

[0003] Japanese Patent Application Laid-Open No. 2021-042020

[0004] By the way, in the work area of a warehouse as described above, a so-called pallet magazine for stacking empty pallets that are not in use or for unstacking the empty pallets to be used from the stacked empty pallets may be installed in order to store the unused empty pallets together. However, conventional pallet magazines are either only compatible with automated guided vehicles or only compatible with hand-pushed carts (such as forklifts) operated by work vehicles.

[0005] However, with the increase in the volume of goods flow in recent years, the number of warehouses that transport goods using both automated guided vehicles and hand-pushed carts in a predetermined work area of a warehouse has been increasing. Along with this, a pallet stacking and unstacking device compatible with both automated guided vehicles and hand-pushed carts is in demand.

[0006] Therefore, the present invention has been made to solve the above-mentioned problems, and aims to provide a pallet stacking and unstacking device that can stack and unstacking pallets in conjunction with both automated guided vehicles and hand trucks.

[0007] To achieve the above objective, the present invention provides a pallet stacking and unstacking device for stacking or unstacking pallets, comprising: a support column extending vertically from the floor surface on which an automated guided vehicle and a hand truck for transporting pallets travel; pallet support claws that move up and down along the support column and support the pallets; and a controller that controls the up and down movement of the pallet support claws, wherein the controller recognizes whether the pallet is being transferred to an automated guided vehicle or a hand truck, and is configured to change the operating height position of the pallet support claws according to whether the pallet is being transferred to an automated guided vehicle or a hand truck based on the recognition.

[0008] With the present invention configured in this way, the controller changes the operating height position of the pallet support claws depending on whether it is an automated guided vehicle (AGV) or a hand truck, so that the stacking and unstacking device can be used in conjunction with both AGVs and hand trucks. In other words, the pallet stacking and unstacking device of the present invention can perform stacking and unstacking of pallets in accordance with both AGVs and hand trucks.

[0009] Furthermore, in the present invention, preferably, the controller is configured to raise and lower the pallet support claws to the pallet height position on the automated guided vehicle (AGV) when it recognizes the pallet transfer partner as an AGV, and to raise and lower the pallet support claws to the pallet height position on the floor when it recognizes the pallet transfer partner as a hand truck. With the present invention configured in this way, when using a hand truck, safety can be ensured by using the floor (the running surface of the AGV and hand truck) as a temporary storage area for the pallet. For example, monitoring of workers becomes unnecessary.

[0010] Furthermore, in the present invention, preferably, the controller recognizes whether the recipient of the pallet is an automated guided vehicle (AGV) or a hand truck based on predetermined information from a higher-level controller for controlling the operation of the AGV, and the support column is equipped with a sensor that detects the height position of the pallet transported to the stacking and unstacking device. With the present invention configured in this way, the sensor can detect whether the pallet transported to the stacking and unstacking device for pallets is a pallet on an AGV or a pallet placed on the floor by a hand truck, thereby enabling the detection of errors in the recipient of the pallet. For example, when the controller recognizes that the recipient of the pallet is an AGV, even if the pallet is placed on the floor by a hand truck, the error can be detected, preventing accidents such as the AGV colliding with the pallet on the floor.

[0011] The pallet stacking and unstacking device of the present invention can stack and unstacking pallets in accordance with both automated guided vehicles and hand trucks.

[0012] This is a perspective view showing the schematic configuration of a stacking and unstacking device for pallets according to an embodiment of the present invention. This is a front view showing the schematic configuration of the stacking and unstacking device for pallets shown in Figure 1. This is a plan view showing the schematic configuration of the stacking and unstacking device for pallets shown in Figure 1. This is a front view showing the schematic configuration of an automated guided vehicle used in an embodiment of the present invention. This is a schematic front view for explaining the first operation of unstacking pallets in automated guided vehicle mode using the stacking and unstacking device according to this embodiment. This is a schematic front view for explaining the second operation of unstacking pallets, following Figure 5A. This is a schematic front view for explaining the third operation of unstacking pallets, following Figure 5B. This is a schematic front view for explaining the fourth operation of unstacking pallets, following Figure 5C. This is a schematic front view for explaining the fifth operation of unstacking pallets, following Figure 5D. This is a schematic front view for explaining the sixth operation of unstacking pallets, following Figure 5E. This is a schematic front view for explaining the first operation of unstacking pallets in hand lift mode using the stacking and unstacking device according to this embodiment. Figure 6A is a schematic front view illustrating the second operation of unstacking pallets. Figure 6B is a schematic front view illustrating the third operation of unstacking pallets. Figure 7C is a schematic front view illustrating the fourth operation of stacking pallets. Figure 7D is a schematic front view illustrating the fifth operation of stacking pallets. Figure 7E is a schematic front view illustrating the sixth operation of stacking pallets. Figure 8A is a schematic front view illustrating the second operation of stacking pallets. Figure 8B is a schematic front view illustrating the third operation of stacking pallets. Figure 8C is a schematic front view illustrating the fourth operation of stacking pallets. This is a schematic front view illustrating the fifth step in stacking pallets, following Figure 8D.This is a schematic front view illustrating the sixth step in stacking pallets, following Figure 8E.

[0013] Next, with reference to the attached drawings, an embodiment of the present invention will be described as a pallet stacking and unstacking device.

[0014] First, the schematic configuration of the pallet stacking and unstacking device and the automated guided vehicle according to embodiments of the present invention will be explained with reference to Figures 1 to 4. Figure 1 is a perspective view showing the schematic configuration of the pallet stacking and unstacking device according to embodiments of the present invention, Figure 2 is a front view showing the schematic configuration of the pallet stacking and unstacking device shown in Figure 1, Figure 3 is a plan view showing the schematic configuration of the pallet stacking and unstacking device shown in Figure 1, and Figure 4 is a front view showing the schematic configuration of the automated guided vehicle used in embodiments of the present invention. First, as shown in Figure 1, reference numeral 1 indicates the stacking and unstacking device according to this embodiment. This stacking and unstacking device 1 is installed at a predetermined location in an area (not shown) to which a transport system that transports goods, etc., by pallets P placed on an automated guided vehicle V or hand lift L, which will be described later, is applied. The area to which this transport system is applied is, for example, a warehouse area inside a building partitioned by predetermined walls, and has a floor surface G that serves as the running surface for the automated guided vehicle V. This floor surface G is also the running surface for the hand lift L operated by a worker.

[0015] Figure 1 shows a hand lift L on which a pallet P is placed. The hand lift L is an example of a transport device (hand truck) on which a worker moves along the floor surface G to transport the pallet P (and other items not shown placed on the pallet P), and is operated manually by the worker.

[0016] The hand lift L is a known type, in which a pair of forks LF are raised and lowered hydraulically relative to the floor surface G, and the pallet P is lifted (placed on the hand lift L) by inserting the pair of forks LF into a pair of insertion holes PA on the pallet P, and the pallet P is transported. The pallet P has a pair of insertion holes PA formed on each of its four sides, and the forks LF are inserted into any pair of insertion holes PA for transport. Goods (not shown) are placed on the top surface of the pallet P.

[0017] As shown in Figures 1 to 3, the stacking and unstacking device 1 is equipped with a lifting unit 2, which is a power slider unit for stacking or unstacking pallets P in a predetermined area (pallet placement area) Ga on the floor surface G. As will be described later, pallets P are transported to the predetermined area Ga where this stacking and unstacking device 1 is installed by an automated guided vehicle V or a hand lift L.

[0018] The lifting unit 2 comprises a pair of support columns 4, a pair of lifter devices (hereinafter referred to as "lifters") 6 that move up and down along the pair of support columns 4, and a pair of pallet support claw members (pallet support claws) 8 (hereinafter referred to as "support claws") 8 provided on these lifters 6. As shown in Figures 1 and 2, the support columns 4 are each installed so as to extend vertically from the floor surface G and are spaced apart in the width direction of the stacking and unstacking device 1.

[0019] As shown in Figures 1 to 3, in this example, each support claw 8 is a plate-shaped member that extends laterally and inward from each of the opposing sides of the lifter 6. As shown in Figures 2 and 3, each support claw 8 is configured to move back and forth between a protruding position where it protrudes inward between the support columns 4 to support the pallet P (see support claw 8a in Figures 2 and 3) and a retracted position where it is stored inside the lifter 6 and support columns 4 (see support claw 8b in Figure 3).

[0020] The pair of lifters 6 are guide devices that guide the raising and lowering of each support claw 8. Inside the pair of support columns 4, there is an electric cylinder (not shown) consisting of a motor or ball screw, etc., which serves as a lifting drive mechanism to raise and lower each lifter 6, so that the pair of lifters 6 move up and down in sync. The electric cylinder may also be an air cylinder or a hydraulic cylinder.

[0021] Furthermore, a drive mechanism (not shown) consisting of an electric motor or the like is provided inside the pair of lifters 6 to cause each support claw 8 to extend and retract. These drive mechanisms cause a total of four support claws 8 to move synchronously between the aforementioned protruding position and retracted position.

[0022] Here, as shown in Figure 2, the lifter 6 and support claws 8 (shown as the support claw 8a in the protruding position in Figure 2) move up and down between a lower position (shown as a solid line) on which the pallet P can be placed on the floor surface G and an upper position (shown as a dashed line) a predetermined distance above that lower position, and can be stopped at any position. In this embodiment, the upper position a predetermined distance above the support claws 8 (the maximum raised position of the support claws 8) is at least a height position such that the automated guided vehicle V on which the pallet P is placed does not come into contact with the pallet P supported by the support claws 8, and is set to a height position such as that shown in Figure 5F, which will be described later.

[0023] Next, as shown in Figure 3, each support claw 8 is operated from the retracted position (8b) to the protruding position (8a) that extends inward between the support columns, and is inserted into the insertion hole PA of the pallet P at a predetermined height position of each support claw 8. Then, by positioning the opposing pair of support claws 8 (a total of four support claws 8) in the protruding position and inserting each support claw 8 into the insertion hole PA of the pallet P, and raising and lowering the lifter 6, the pallet P can be raised and lowered. On the other hand, each pair of support claws 8 is operated from the protruding position to the retracted position, and is withdrawn from the insertion hole PA of the pallet P.

[0024] Furthermore, as shown in Figures 1 and 2, the support columns 4 of the stacking and unstacking device 1 are equipped with sensors 14 for detecting pallets P transported to the device 1. Although only one sensor 14 is shown on one side in Figure 2, this sensor 14 is a photoelectric sensor in which a light source and light receiver set to have a horizontal optical axis are installed on one of the pair of support columns, and a reflector is installed on the other support column, and multiple sensors are installed in the height direction of the pair of support columns 4. With multiple such photoelectric sensors (14), the presence or absence of pallets P and their position in the height direction can be detected. Alternatively, instead of such photoelectric sensors, a single laser sensor that scans in the vertical direction to detect objects may be installed to detect pallets P and their height position.

[0025] Here, as shown in Figure 2, the stacking and unstacking device 1 has a controller 10 (shown only in Figure 2) that controls the lifting and lowering operation of the lifter 6 of the lifting unit 2 and the extending and retracting operation of the support claws 8, respectively. In this embodiment, a higher-level controller 12 is provided that controls the operation of various devices, including an automated guided vehicle V, within the area to which the above-described transport system is applied, and the lifting and lowering operation of the lifter 6 of the lifting unit 2 and the extending and retracting operation of the support claws 8 may be controlled by this higher-level controller 12.

[0026] Furthermore, the controller 10 can also control the lifting and lowering operation of the lifter 6 based on the detection signal from the sensor 14. For example, in an operation situation where a pallet P is transferred to and from an automated guided vehicle V (for example, the automated guided vehicle mode described later), if the pallet P is placed on the floor surface G (which is normally placed in hand-lift mode), the controller 10 can send an error signal to stop the lifting and lowering operation of the lifter 6, or change the operation to the hand-lift mode described later. Note that the controller 10 may be divided into a controller for controlling the operation of the lifter 6 and support claws 8 of the stacking and unstacking device 1, and a controller for controlling the operation of the automated guided vehicle V. Specifically, the controller 10 and the higher-level controller 12 are composed of a microprocessor, interface circuit, communication circuit, memory, and software to operate them (these are not shown).

[0027] Next, as shown in Figure 4, the Automated Guided Vehicle (AGV) V is an automated guided vehicle that carries and transports the pallet P described above, and has a lifter VL for raising and lowering the pallet P. In this embodiment, multiple AGVs V are operating within the area to which the transport system described above is applied, and they automatically travel along a predetermined travel line in that area based on instructions via wireless communication from the higher-level controller 12. Note that only one AGV V may be in operation. Here, in the predetermined area Ga area where the stacking and unstacking device 1 is installed, the travel operation, stopping operation of the AGV V, and the raising and lowering operation of the lifter VL are controlled by the controller 10 of the stacking and unstacking device 1, or by the higher-level controller 12 of the transport system.

[0028] Furthermore, in this embodiment, the controller 10 can be set to one of the following operating modes for the stacking and unstacking device 1: an automated guided vehicle (AGV) mode in which empty pallets P are mainly transported using an AGV; a hand lift mode in which empty pallets P are mainly transported manually by an operator using a hand lift L; or a shared mode that allows both transport by AGV V and transport by hand lift L. In addition, even in AGV mode, operators may be permitted to use hand lifts in designated areas.

[0029] The higher-level controller 12 defines and stores a plan for the order and timing of stacking and unstacking pallets P, based on a predetermined work plan, for example, formulated and input by the warehouse user, or automatically determined according to the warehouse's operating status. The higher-level controller 12 then transmits signals to the stacking and unstacking device 1 and the automated guided vehicle V to instruct the defined order and timing of stacking and unstacking pallets P. The higher-level controller 12 also transmits such signals to a worker management device (not shown).

[0030] The controller 10 receives the signal and, when performing the unstacking and stacking of pallets as described below, recognizes whether the transport device used for unstacking or stacking the pallets is an automated guided vehicle (AGV) or a hand lift L. In other words, based on the received signal, the controller 10 determines / decides and stores the order and timing in which to execute the AGV mode, hand lift mode, or shared mode described above. Naturally, the signals received by the controller 10 also include signals indicating whether to perform unstacking or stacking.

[0031] Furthermore, the controller 10 itself may determine (recognize) the automated guided vehicle mode and hand lift mode, etc. (without relying on signals from the higher-level controller 12), and may also determine (recognize) whether to perform unstacking or stacking. Alternatively, the operator may set each mode via a predetermined input device on the controller 10.

[0032] [Unstacking by Automated Guided Vehicle] Next, with reference to Figures 5A to 5F, the unstacking operation of the pallet P by the automated guided vehicle V, controlled by the controller 10, in the stacking and unstacking device 1 according to this embodiment will be explained. Figure 5A is a schematic front view illustrating the first operation of unstacking the pallet in automated guided vehicle mode by the stacking and unstacking device according to this embodiment, Figure 5B is a schematic front view illustrating the second operation of unstacking the pallet, following Figure 5A, Figure 5C is a schematic front view illustrating the third operation of unstacking the pallet, following Figure 5B, Figure 5D is a schematic front view illustrating the fourth operation of unstacking the pallet, following Figure 5C, Figure 5E is a schematic front view illustrating the fifth operation of unstacking the pallet, following Figure 5D, and Figure 5F is a schematic front view illustrating the sixth operation of unstacking the pallet, following Figure 5E. Note that the lifter 6 is not shown in Figures 5A to 5F. The operation of the lifter 6, support claws 8, and automated guided vehicle (AGV) V, as described below, is controlled by the controller 10. The AGV V is controlled by instructions transmitted from the controller 10 to the AGV V via the higher-level controller 12.

[0033] Firstly, as shown in Figure 5A, an operator uses a hand lift L (not shown in Figure 6A) to transport the stacked pallets P (eight pallets in the example in Figure 5A) to area Ga of the stacking and unstacking device 1 (see Figures 1 and 3). Alternatively, as will be described later, the stacked pallets P may be transported by an automated guided vehicle V based on instructions from the controller 10.

[0034] Secondly, the lifter 6 is positioned in a lower position, and the support claws 8 are extended in that lower position, thereby inserting the support claws 8 into the insertion holes (PA) of the lowest pallet P1 (see the lifter 6, support claws 8, etc., shown by the solid lines in Figure 2). Then, from that state, the lifter 6 is raised so that the stacked pallets P are lifted to the upper position, as shown in Figure 5B. Note that this raised position may be lower than the maximum raised position described above, as long as it is a height at which the lifted pallet P does not come into contact with the automated guided vehicle V in the next third operation (for example, a position one pallet's height lower than the maximum raised position).

[0035] Thirdly, as shown in Figure 5C, the automated guided vehicle V is moved beneath the lifted stacked pallets P.

[0036] Fourth, as shown in Figure 5D, the lifter 6 is lowered so that the bottommost pallet P1 rests on the lifter VL of the automated guided vehicle V, thereby placing the stacked pallets P onto the automated guided vehicle V.

[0037] Fifth, at that position, the support claws 8 are returned to their retracted position, and the lifter 6 is raised by one pallet level. Then, as shown in Figure 5E, at that raised position, the support claws 8 are extended to support the second pallet P2 from the bottom, and the lifter 6 is raised, thereby lifting a total of seven stacked pallets P.

[0038] Sixth, as shown in Figure 5F, the unpacking is complete when only one pallet P1 is placed on the automated guided vehicle V. The automated guided vehicle V then transports the pallet P1 to the designated work position. If unpacking is to be continued, the third to fifth operations described above are repeated.

[0039] In the first operation shown in Figure 5A, the stacked pallets P are transported to the device 1 by a hand lift L, but this may be done by an automated guided vehicle (AGV). In this case, as the first operation, first the stacked pallets P are transported by the AGV V, then the bottommost pallet (P1) of the stacked pallets P on the AGV V is lifted by the lifter 6 and support claws 8, then the AGV V is moved out of area Ga of the device 1 (see Figure 1), then the lifter 6 is lowered so that the bottommost pallet P1 is placed on the floor surface G of area Ga, and then the unstacking of the pallets from the second operation onward can be started. In this case, the unstacking may be started while the bottommost pallet P1 is still lifted to a predetermined height by the support claws 8, without being lowered to the floor surface G.

[0040] [Unstacking using a hand lift] Next, with reference to Figures 6A to 6C, the unstacking operation of pallets P using a hand lift L controlled by a controller 10 in the stacking and unstacking device 1 according to this embodiment will be explained. Figure 6A is a schematic front view illustrating the first operation of unstacking pallets in hand lift mode by the stacking and unstacking device according to this embodiment, Figure 6B is a schematic front view illustrating the second operation of unstacking pallets, following Figure 6A, and Figure 6C is a schematic front view illustrating the third operation of unstacking pallets, following Figure 6B. Note that the lifter 6 is not shown in Figures 6A to 6C. The operation of the lifter 6, support claws 8, and automated guided vehicle V, which will be described below, is controlled by the controller 10. Note that the automated guided vehicle V is controlled by instructions transmitted from the controller 10 to the automated guided vehicle V via a higher-level controller 12.

[0041] Firstly, as shown in Figure 6A, a worker uses a hand lift L (not shown in Figure 6A) to transport stacked pallets P (eight pallets in the example in Figure 6A) to area Ga of the stacking and unstacking device 1 (see Figures 1 and 3).

[0042] Second, with respect to the stacked pallets P placed on the floor surface G, the support claws 8 are raised to the height position of the second pallet P2 from the bottom, and at that height position, the support claws 8 are moved to the protruding position. As shown in FIG. 6B, the second pallet P2 from the bottom is supported and the lifter 6 is raised, thereby lifting the stacked pallets P for a total of seven levels. Note that when lifting such pallets, the support claws 8 may be raised to the same height position as when the pallets are separated by the automated guided vehicle V as shown in FIG. 5E, or alternatively, the second pallet P may be raised by the minimum height such that the second pallet P is separated from the first pallet P1 on the floor surface G.

[0043] Third, as shown in FIG. 6C, only one pallet P1 is placed on the floor surface G, and the pallet separation is completed. Thereafter, the operator operates the hand lift L to transport the pallet P1 to a predetermined work position. When continuing the pallet separation, the second operation to the third operation described above is repeated. Note that in this hand lift mode, the pallet P may be placed not only on the floor surface G but also on the hand lift L.

[0044] [Regarding the operating height position of the support claws 8 in pallet separation] Here, the difference in the operating height position of the support claws 8 when using an automated guided vehicle or a hand lift (hand pallet truck) for pallet separation will be described. First, in the case of the automated guided vehicle V, after placing the stacked pallets P on the automated guided vehicle V as in the fourth and fifth operations described above (FIG. 5D), the second pallet P2 from the bottom is supported to lift the stacked pallets P (FIG. 5E). On the other hand, in the case of the hand lift L, as in the second and third operations described above, with respect to the stacked pallets P placed on the floor surface G, the second pallet P2 from the bottom is supported to lift the stacked pallets P (FIG. 6B).

[0045] Thus, in this embodiment, the operating height position of the support claws 8 is changed to the height of the pallet P on the automated guided vehicle (AGV) or the height of the pallet P on the floor, or more precisely, to the height of the second pallet P2 on the floor, depending on whether the conveying device used to unpack the pallet P and transfer the pallet P to and from the device 1 is an AGV or a hand lift L.

[0046] Such an operating height position is controlled by the controller 10 after it recognizes whether the transport device used to unpack the pallets P is an automated guided vehicle (AGV) V or a hand lift L. In this embodiment, the controller 10 recognizes whether the transport device used to unpack the pallets P is an AGV V or a hand lift L based on predetermined information received from the higher-level controller 12, such as an AGV mode or a hand lift mode. However, it is not limited to this, and for example, information from the sensor 14 may be used to determine whether the transport device used to unpack the pallets P is an AGV V or a hand lift L.

[0047] [Stacking by Automated Guided Vehicle] Next, with reference to FIGS. 7A to 7F, the stacking operation of the pallet P by the automated guided vehicle V, which is controlled by the controller 10 in the stacking and leveling device 1 according to the present embodiment, will be described. FIG. 7A is a schematic front view for explaining the first operation of pallet stacking in the automated guided vehicle mode by the stacking and leveling device according to the present embodiment, FIG. 7B is a schematic front view following FIG. 7A for explaining the second operation of pallet stacking, FIG. 7C is a schematic front view following FIG. 7B for explaining the third operation of pallet stacking, FIG. 7D is a schematic front view following FIG. 7C for explaining the fourth operation of pallet stacking, FIG. 7E is a schematic front view following FIG. 7D for explaining the fifth operation of pallet stacking, and FIG. 7F is a schematic front view following FIG. 7E for explaining the sixth operation of pallet stacking. In FIGS. 7A to 7F, the illustration of the lifter 6 is omitted. The operations of the lifter 6, the support claws 8, and the automated guided vehicle V described below are controlled by the controller 10. Regarding the automated guided vehicle V, instructions from the controller 10 are transmitted to the automated guided vehicle V via the host controller 12 and controlled.

[0048] First, as shown in FIG. 7A, the automated guided vehicle V transports one pallet P1 to the area Ga (see FIGS. 1 and 3) of the stacking and leveling device 1.

[0049] Second, the lifter 6 is raised and lowered to the position of the pallet P1 on the automated guided vehicle V and is made to standby. At that position, the support claws 8 are set to the protruding position, so that the support claws 8 are inserted into the insertion holes (PA) of the pallet P1. Then, from that state, as shown in FIG. 7B, the lifter 6 is raised so that the pallet P1 is lifted to the upper position.

[0050] Third, as shown in FIG. 7C, the automated guided vehicle V transports the next pallet P2 below the lifted pallet P1.

[0051] Fourth, as shown in FIG. 7D, the lifter 6 is lowered so that the pallet P1 held by the support claws 8 is placed on the pallet P2 on the automated guided vehicle V.

[0052] Fifth, at that position, the support claws 8 are returned to the retracted position, and the lifter 6 is lowered by one pallet level. Then, as shown in Figure 7E, at the lowered position, the support claws 8 are extended to support the pallet P2 on the automated guided vehicle V, and the lifter 6 is raised, thereby lifting pallets P2 and P1.

[0053] Sixth, the controller 10 repeatedly executes the third to fifth operations described above (Figures 7C to 7E) until the desired number of layers (eight layers in this example) of stacking is completed, as shown in Figure 7F. Then, as shown in Figure 7F, the automated guided vehicle (AGV) V enters the device 1 to receive the stacked pallets P. The lifter 6 is lowered so that the stacked pallets P are placed on the lifter VL of the AGV V, and the support claws 8 are retracted. This allows the AGV V to transport the stacked pallets P to a predetermined work position. Alternatively, after the stacking is complete, the stacked pallets P may be transported to a predetermined work position using a hand lift L. In this case, the lifter 6 is lowered so that the stacked pallets P are placed on the floor G, and the support claws 8 are retracted.

[0054] [Stacking with a Handlift] Next, the stacking operation of pallets P using a handlift L controlled by a controller 10 in the stacking and unstacking device 1 according to this embodiment will be explained with reference to Figures 8A to 8F. Figure 8A is a schematic front view illustrating the first operation of stacking pallets in handlift mode by the stacking and unstacking device according to this embodiment, Figure 8B is a schematic front view illustrating the second operation of stacking pallets, following Figure 8A, Figure 8C is a schematic front view illustrating the third operation of stacking pallets, following Figure 8B, Figure 8D is a schematic front view illustrating the fourth operation of stacking pallets, following Figure 8C, Figure 8E is a schematic front view illustrating the fifth operation of stacking pallets, following Figure 8D, and Figure 8F is a schematic front view illustrating the sixth operation of stacking pallets, following Figure 8E. Note that the lifter 6 is not shown in Figures 8A to 8F. The operation of the lifter 6, support claws 8, and automated guided vehicle (AGV) V, as described below, is controlled by the controller 10. The AGV V is controlled by instructions transmitted from the controller 10 to the AGV V via the higher-level controller 12.

[0055] Firstly, as shown in Figure 8A, a worker uses a hand lift L to transport the stacked pallets P (in the example in Figure 6A, nine pallets) to area Ga of the stacking and unstacking device 1 (see Figures 1 and 3).

[0056] Secondly, the lifter 6 is lowered to a position below the pallet P1 on the floor surface G and placed in standby position, with the support claws 8 in a protruding position so that the support claws 8 can be inserted into the insertion holes (PA) of the pallet P1. Then, from that state, the lifter 6 is raised so that the pallet P1 is lifted to an upper position, as shown in Figure 8B.

[0057] Thirdly, as shown in Figure 8C, the worker uses a hand lift L to transport the next pallet P2 below the lifted pallet P1.

[0058] Fourth, as shown in Figure 8D, the lifter 6 is lowered so that the pallet P1, held by the support claws 8, rests on the pallet P2 on the floor surface G.

[0059] Fifth, at that position, the support claws 8 are returned to their retracted position, and the lifter 6 is lowered by one pallet level. Then, as shown in Figure 8E, at that lowered position, the support claws 8 are set to their protruding position to support the pallet P2 on the floor surface G, and the lifter 6 is raised, thereby lifting pallets P2 and P1.

[0060] Sixth, the controller 10 repeatedly executes the third to fifth operations described above (Figures 8C to 8E) until the desired number of pallets (eight in this example) are stacked, as shown in Figure 8F. Then, as shown in Figure 8F, the automated guided vehicle (AGV) V enters the device 1 to receive the stacked pallets P. The lifter 6 is then lowered so that the stacked pallets P are placed on the lifter VL of the AGV V, and the support claws 8 are retracted. This allows the AGV V to transport the stacked pallets P to a predetermined work position. Alternatively, as described above, the stacked pallets P may be transported to a predetermined work position using a hand lift L.

[0061] [Regarding the operating height position of the support claws 8 in stacking] Here, we will explain the difference in the operating height position of the support claws 8 when using an automated guided vehicle (AGV) or a hand lift (hand truck) for stacking pallets. First, in the AGV V, as described in the second step above, the pallet P1 on the AGV V is lifted (Figures 7A and 7B). On the other hand, in the hand lift L, as described in the second step above, the pallet P1 on the floor surface G is lifted (Figures 8A and 8B).

[0062] Furthermore, in the automated guided vehicle (AGV) V, as described in the fourth and fifth operations above, after placing pallet P1, held by support claws 8, on pallet P2 on the AGV V (Figure 7D), pallet P2 on the AGV V is supported to lift pallet P2 and pallet P1 (Figure 7E). On the other hand, in the hand lift L, as described in the fourth and fifth operations above, after placing pallet P1, held by support claws 8, on pallet P2 on the floor surface G (Figure 8D), pallet P2 on the floor surface G is supported to lift pallet P2 and pallet P1 (Figure 8E).

[0063] Thus, in this embodiment, the operating height position of the support claws 8 is changed to the height of the pallet P on the automated guided vehicle (AGV) or to the height of the pallet P on the floor, depending on whether the conveying device used for stacking the pallets P and transferring them between the device 1 is an AGV or a hand lift L.

[0064] Such operating height positions are controlled by the controller 10 after it recognizes whether the transport device used to unpack the pallet P is an automated guided vehicle (AGV) or a hand lift L. In this embodiment, the controller 10 recognizes whether the transport device used to unpack the pallet P is an AGV or a hand lift L based on predetermined information received from the higher-level controller 12, such as an AGV mode or a hand lift mode. However, it is not limited to this, and for example, information from the sensor 14 may be used to determine whether the transport device used to unpack the pallet P is an AGV or a hand lift L. Also, when raising or lowering the support claws 8, especially when lowering the support claws 8 in hand lift mode, the sensor 14 may be used to confirm that the hand lift L is not present in a predetermined area Ga of the device 1.

[0065] Next, the operation and effects of a pallet stacking and unstacking device according to an embodiment of the present invention will be explained. First, the pallet stacking and unstacking device 1 according to this embodiment for stacking or unstacking pallets comprises a support column 4 extending vertically from the floor surface G on which an automated guided vehicle V and a hand lift (hand truck) L for transporting pallets P travel, a pallet support claw 8 that moves up and down along the support column 4 and supports the pallet P, and a controller 10 that controls the up and down movement of the pallet support claw. The controller 10 recognizes whether the recipient of the pallet P is an automated guided vehicle V or a hand lift L, and is configured to change the operating height position of the pallet support claw 8 according to this recognition, depending on whether the recipient of the pallet P is an automated guided vehicle V or a hand lift L. With this configuration, the controller 10 changes the operating height position of the pallet support claw 8 according to whether it is an automated guided vehicle V or a hand lift L, so that the stacking and unstacking device can be shared between an automated guided vehicle V and a hand lift L. In other words, the pallet stacking and unstacking device of the present invention can perform stacking and unstacking of pallets in accordance with both automated guided vehicles and hand lifts.

[0066] Furthermore, according to this embodiment, the controller 10 is configured to raise and lower the pallet support claws 8 to the pallet height position on the automated guided vehicle V when it recognizes the recipient of the pallet P as an automated guided vehicle V, and to raise and lower the pallet support claws 8 to the pallet height position on the floor surface G when it recognizes the recipient of the pallet P as a hand lift L. With this configuration, when using the hand lift L, safety can be ensured by using the floor surface G (the running surface of the automated guided vehicle V and the hand lift L) as a temporary storage area for the pallet P. For example, monitoring of workers becomes unnecessary.

[0067] Furthermore, according to this embodiment, the controller 10 recognizes whether the recipient of the pallet P is the automated guided vehicle (AGV) V or the hand lift L based on predetermined information from the higher-level controller 12 for controlling the operation of the AGV, and the support column 4 is equipped with a sensor 14 that detects the height position of the pallet P transported to the stacking and unstacking device 1. With this configuration, the sensor 14 can detect whether the pallet P transported to the stacking and unstacking device 1 is a pallet P on the AGV V or a pallet placed on the floor G by the hand lift L, and can detect errors in the recipient of the pallet P. For example, when the controller 10 recognizes that the recipient of the pallet P is the AGV V, even if the pallet P is placed on the floor G by the hand lift L, the error can be detected, and accidents such as the AGV V colliding with the pallet on the floor G can be prevented.

[0068] G Floor surface, running surface Ga Pallet placement area in stacking and unstacking device P Pallet PA Insertion hole of pallet V Automated vehicle VL Lifter of automated vehicle L Hand lift (Hand lift L) LF Lift fork 1 Stacking and unstacking device 2 Lifting device 4 Support column 6 Lifter device 8 Pallet support claw member (pallet support claw) 8a Support claw in protruding position 8b Support claw in retracted position 10 Controller 12 Higher-level controller 14 Sensor

Claims

1. A pallet stacking and unstacking device for stacking or unstacking pallets, comprising: a support column extending vertically from the floor surface on which an automated guided vehicle and a hand truck for transporting pallets travel; pallet support claws that move up and down along the support column and support the pallets; and a controller that controls the up and down movement of the pallet support claws, wherein the controller recognizes whether the recipient of the pallet is an automated guided vehicle or a hand truck, and is configured to change the operating height position of the pallet support claws according to whether the recipient of the pallet is an automated guided vehicle or a hand truck based on the recognition.

2. The pallet stacking and unstacking device according to claim 1, wherein the controller is configured to raise and lower the pallet support claws to the pallet height position on the automated guided vehicle when the recipient of the pallet is recognized as the automated guided vehicle, and to raise and lower the pallet support claws to the pallet height position on the floor when the recipient of the pallet is recognized as the hand truck.

3. The pallet stacking and unstacking device according to claim 1 or 2, wherein the controller recognizes whether the recipient of the pallet is an automated guided vehicle or a hand truck based on predetermined information from a higher-level controller for controlling the operation of the automated guided vehicle, and the support column is equipped with a sensor for detecting the height position of the pallet that has been transported to the stacking and unstacking device.

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