Transfer device

Abstract

This transfer device comprises: a first arm having two claws for supporting one tray by abutting on a supported part of the tray; an advancing / retracting device for advancing and retracting the first arm; a raising / lowering device for raising and lowering the first arm; and a controller for controlling movement of the first arm. The controller controls the advancing / retracting device and the raising / lowering device to move the first arm so that a plurality of trays are stacked on a stacking body of trays disposed at a prescribed position, and to move the first arm so that a plurality of trays including one discretionary tray from within the stacking body are collectively removed from the stacking body.

Description

Transfer equipment

[0001] The present disclosure relates to a transfer device that transfers trays.

[0002] Conventionally, transfer devices that transfer trays containing articles are known. In the system described in Patent Document 1, multiple trays are stacked and carried in by a carry-in conveyor. A de-stack device is provided along the path of the carry-in conveyor. The de-stack device leaves only the bottom tray on the conveyor, lifts the multiple trays above it, and transports the remaining tray downstream. By repeating this process, the carry-in stack is separated into individual trays. In addition, each tray is carried out by an unloading conveyor. A stacking device is provided along the path of the unloading conveyor. The stacking device stacks the trays one by one to form the unloading stack.

[0003] International Publication No. 2021 / 171709

[0004] The above-mentioned conventional systems and devices can only separate and transport one tray at a time, or stack one tray at a time, but cannot separate or stack multiple trays at once.

[0005] The present disclosure describes a transfer device that can simultaneously stack multiple tiers of different trays onto a stack of trays, or simultaneously remove multiple tiers of trays, including any tray, from the stack.

[0006] [1] One aspect of the present disclosure is a transfer device for transferring multiple tiers of trays, comprising: a first arm having two forks that abut against a supported portion of a single tray to support the tray; an advance / retract device for moving the first arm forward and backward; a lifting / lowering device for raising and lowering the first arm; and a controller for controlling the movement of the first arm, wherein the controller controls the advance / retract device and the lifting / lowering device to move the first arm so as to stack multiple tiers of trays on a stack of trays arranged at a predetermined position, and to move the first arm so as to remove multiple tiers of trays, including any one tray from the stack, all at once.

[0007] According to the transfer device of [1], the first arm can be raised and lowered and can be stopped at any height by controlling the lifting and lowering device. The first arm can advance its two claws to the position of the supported portion of the tray and retract them from the position of the supported portion by controlling the forward and backward movement device. By controlling the first arm, which moves on at least two axes, with a controller, the transfer device can stack multiple tiers of different trays at once on a stack placed at a predetermined position. The number of tiers in the stack is not particularly limited, and the number of trays to be stacked is also not particularly limited. Furthermore, the transfer device can simultaneously remove multiple tiers of trays, including any tray, from the stack. The first arm may support any tray in the stack. All trays stacked above the supported tray, including the supported tray, are removed. Therefore, the number of trays to be removed is not particularly limited. Multiple tiers of trays can be freely handled within the load capacity and performance limits of each device.

[0008] [2] The transfer device of [1] above may further include a left-right movement device that moves the first arm left and right. In this case, the degree of freedom in layout in a system including other transport devices such as conveyors is improved.

[0009] [3] The transfer device of [1] or [2] above may further include a second arm positioned below the first arm and having two claws that can contact the top tray of the stack, and the controller may move the second arm to align the top tray before stacking multiple trays on the stack. According to this control, the top tray is aligned by the second arm, thereby adjusting the posture of the entire stack. This allows multiple trays to be stacked in a more stable state.

[0010] [4] In any one of the transfer devices [1] to [3] above, the first arm may include a sensor provided at the tip of at least one claw, and the controller may input a signal from the sensor to detect at least one of the position of the supported portion of any one tray and the number of trays in the stack. With this configuration, the controller can accurately grasp the position of the supported portion of the tray via the first arm and reliably support the tray. Alternatively, the controller can reliably identify multiple trays to be removed by grasping the number of trays in the stack. For example, this can prevent the first arm from being moved to a position in the air where no trays are present.

[0011] [5] In the transfer device of any one of [1] to [4] above, the stack may be placed on a pallet installed in a predetermined position, and a positioning guide for positioning the bottom tray of the stack may be provided on the top surface of the pallet. With this configuration, the bottom tray of the stack is placed in an appropriate position, so that each tray in the stack formed on the pallet also maintains a relatively appropriate position and posture. Therefore, multiple trays can be stacked on the stack and multiple trays can be removed from the stack without any problems.

[0012] According to the present disclosure, multiple trays can be stacked together in a stack of trays, and multiple trays including any tray can be removed from the stack at once.

[0013] FIG. 1 is a plan view showing a conveying system to which a transfer device according to an embodiment of the present disclosure is applied. FIG. 2 is a front view of the conveying system of FIG. 1. FIG. 3 is a side view of the conveying system of FIG. 1. FIG. 4 is a side view showing a stack of trays being conveyed by a first arm. FIG. 5 is a plan view showing a state in which trays are aligned by a second arm. FIG. 6(a) is a side view of the claws of the first arm, and FIG. 6(b) is a side view of the claws of the second arm. FIG. 7 is a plan view showing a stack of trays being conveyed toward a fixing station. FIG. 8 is a side view showing a state in which the top tray of a stack of trays is aligned by the second arm before the stack of trays is stacked. FIG. 9(a) is a front cross-sectional view showing a state in which the claws of the second arm are inserted into the insertion position for the top tray, and FIG. 9(b) is a front cross-sectional view showing a state in which the claws of the second arm are aligning the tray. FIG. 10 is a side view, subsequent to FIG. 8, showing a state in which the stack of trays has been moved upward in the stack of trays by the first arm. Figure 11(a) is a front cross-sectional view showing the state in which the tray stack has been moved above the stack by the first arm, and Figure 11(b) is a front cross-sectional view showing the state in which the tray stack has been stacked on top of the stack.

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated description will be omitted.

[0015] In the following description, for ease of explanation, reference will be made to orthogonal X, Y, and Z axes shown in several figures. For example, as shown in FIGS. 1 to 3, the X axis is oriented in one horizontal direction, and the Y axis is oriented in another horizontal direction perpendicular to the X axis. The Z axis is oriented perpendicular to both the X and Y axes and is oriented in the vertical direction (i.e., up and down). In this specification, with respect to the transfer device 1 as the reference, the + (plus) X direction corresponds to the leftward direction, and the opposite - (minus) X direction corresponds to the rightward direction. With respect to the transfer device 1 as the reference, the +Y direction corresponds to the forward direction, and the opposite -Y direction corresponds to the backward direction. Furthermore, the +Z direction corresponds to the upward direction, and the opposite -Z direction corresponds to the downward direction. As shown in FIG. 1, the +Y direction, i.e., the forward direction, is the direction in which the first arm 20 approaches the fixed station 200 (stack T). The -Y direction, i.e., the backward direction, is the direction in which the first arm 20 moves away from the fixed station 200 (stack T). Furthermore, when simply referring to the "X direction," the "Y direction," and the "Z direction," they mean the "left-right direction," the "front-rear direction," and the "up-down direction," respectively.

[0016] 1 to 3, a transfer device 1 according to this embodiment and a conveying system S to which the transfer device 1 is applied will be described. As shown in FIGS. 1 to 3, the conveying system S is a system that conveys a plurality of trays 10, each containing an article. Each tray 10 has the same shape, e.g., a flat rectangular shape. The articles contained in each tray 10 are not particularly limited. Examples of the articles that can be contained include electronic components and secondary battery materials. Furthermore, at least one tray 10 (or all trays 10) may not contain an article. In other words, at least one empty tray 10 may be conveyed.

[0017] Multiple trays 10 can be stacked on top of each other. Each tray 10 has a rectangular recess 17 on its top surface 15 (see FIG. 11( a)). When one tray 10 is stacked on top of another, the rectangular bottom surface 18 of the upper tray 10 fits into (fits into) the recess 17 of the lower tray 10. In plan view, the recess 17 is slightly larger than the bottom surface 18. That is, the upper tray 10 fitted into the recess 17 can move slightly in the horizontal direction (left-right and front-back directions).

[0018] In the conveying system S, multiple tiers of trays 10 are conveyed and transferred at the fixed station 200. The number of trays 10 to be conveyed (i.e., transferred) in the conveying system S is multiple. This number of trays 10 may be fixed or variable. For simplicity, the following description will be given assuming that there are always five trays 10 to be conveyed (a fixed number) (see FIG. 3). The five trays 10 to be conveyed are trays 10 stacked in five tiers (multiple tiers), and will be referred to as a "tray pile Ta" hereinafter. The tray pile Ta may also be referred to as a tray stack or the like.

[0019] 1 and 3 , the conveying system S includes a transfer conveyor 100 that horizontally transfers a stack of trays Ta, and an intermediary conveyor 110 that relays the stack of trays Ta transferred by the transfer conveyor 100. The conveying system S also includes a fixed station 200 that can hold a plurality of stacks of trays Ta, and a transfer device 1 that transfers the stack of trays Ta between the fixed station 200 and the intermediary conveyor 110. The transfer conveyor 100, the intermediary conveyor 110, and the fixed station 200 each have, for example, a known configuration. The transfer conveyor 100 and the intermediary conveyor 110 may be roller conveyors, or other conveyors (such as belt conveyors or chain conveyors). Between a transfer position 100a of the transfer conveyor 100 and an intermediary position 110a of the intermediary conveyor 110, the stack of trays Ta is transferred by a switching conveyor, a separate transfer device, or the like.

[0020] As shown in FIG. 2 , the fixed station 200 has, for example, four legs 201 and a horizontal mounting table 202 supported by the legs 201. As shown in FIG. 1 , the mounting table 202 has an area capable of mounting a total of four trays 10, two on the left and right and two on the front and back. As shown in FIG. 2 , one pallet PL is mounted on the mounting table 202 (see also FIG. 8 ). The pallet PL is positioned relative to the mounting table 202 in the left-right direction (X direction) and the front-back direction (Y direction). The fixed station 200 is disposed at a predetermined position within the conveyance system S. The fixed station 200 is disposed at an appropriate position in front of the transfer device 1. The pallet PL has an area capable of mounting a total of four trays 10, two on the left and right and two on the front and back. Each tray 10 is positioned at one of four mounting positions on the pallet PL. The fixed station 200 has a first placing section 203, a second placing section 204, a third placing section 205, and a fourth placing section 206 corresponding to these four placing positions.

[0021] In this embodiment, a stack of trays Ta consisting of multiple trays 10 is placed on the pallet PL. Therefore, one or more stacks of trays Ta can be placed on the first placement section 203. One or more stacks of trays Ta can be placed on the second placement section 204. One or more stacks of trays Ta can be placed on the third placement section 205. One or more stacks of trays Ta can be placed on the fourth placement section 206. In the following description, one or more stacks of trays Ta stacked on the fixed station 200 are referred to as a stack T (consisting of multiple trays 10). For example, as shown in FIG. 2 , three stacks of trays Ta are placed on one placement section on the pallet PL, i.e., 15 trays 10 (15 tiers). The number of trays 10 placed on the pallet PL is not particularly limited.

[0022] A positioning guide (not shown) is provided on the upper surface of the pallet PL to position the bottom tray 10 of the stack T. The positioning guide may be, for example, a rib that is cross-shaped in a plan view. The positioning guide is formed as a protrusion, protruding portion, rib, or the like that protrudes from the upper surface of the pallet PL at a position near the boundary between the four loading positions.

[0023] The transport system S may include, for example, multiple AGVs (Automated Guided Vehicles) (not shown). The multiple AGVs travel autonomously along a route set on the floor surface F. A pallet PL supporting one or multiple (e.g., up to four) stacks T may be transported from the fixed station 200 by the AGV. In this case, a new pallet PL is set (placed) on the placement table 202 of the fixed station 200 by the AGV. The AGV appropriately rotates the pallet PL and places it on the placement table 202 so that the portion to be transferred is located at the third placement section 205 or the fourth placement section 206 on the near side as viewed from the transfer device 1. The portion to be transferred is an empty space on the pallet PL, a stack T, or the like, and is a portion to be accessed by the transfer device 1.

[0024] Next, we will explain the configuration related to the function of transferring tray stack Ta provided in the transfer device 1. As shown in Figures 1 to 3, the transfer device 1 includes a lateral moving body 3 on which a first arm 20 and a second arm 30, which are arranged in two stages, are mounted, and a base 2 that supports the lateral moving body 3. The base 2 is fixed to a floor surface F.

[0025] The transfer device 1 includes a left-right movement device M1 that moves the lateral mover 3 left and right on the platform 2. The platform 2 has a pair of guide rails 2a that are spaced apart in the front-rear direction and extend parallel to the left and right direction. The lateral mover 3 has a slide base 4 that is supported by the guide rails 2a and is movable left and right along the guide rails 2a. The left-right movement device M1 includes a pair of guide rails 2a that guide the slide base 4, a ball screw 2b that extends left and right at an intermediate position on the guide rails 2a, and a motor 61 that moves the slide base 4 left and right by rotating the ball screw 2b. The ball screw 2b and motor 61 are incorporated in the platform 2. The motor 61 is a motor that enables position control of the slide base 4 (lateral mover 3) in the left and right direction, and is, for example, a servo motor.

[0026] The first arm 20 and the second arm 30 are provided on the lifting body 6 that forms part of the lateral mover 3. Specifically, the lifting body 6 has a pair of masts 5 that are erected on the slide base 4 and extend in the vertical direction, a support body 7 that can rise and fall freely along the masts 5, and a rectangular parallelepiped frame 8 that is supported by the support body 7. The first arm 20 and the second arm 30 are attached to the frame 8. The support body 7 includes a base portion 7a that holds the frame 8, and a support portion 7b that extends in the vertical direction above the base portion 7a and moves along a guide rail or the like provided on the surface of the mast 5.

[0027] The transfer device 1 includes a lifting / lowering device M2 that raises and lowers the lifting body 6 on the slide base 4. The pair of masts 5 have a length (height) corresponding to the vertical stroke required for the first arm 20 and the second arm 30 to access the multiple stacks T on the fixed station 200. The masts 5 support the frame 8, the first arm 20, and the second arm 30 via supports 7. The lifting / lowering device M2 includes the masts 5, the supports 7, a motor 62 fixed to the slide base 4, and a driving force transmission unit 9 that transmits the rotational driving force of the motor 62 to the supports 7. The driving force transmission unit 9 includes a cylinder unit 9b extending vertically at the center of the pair of masts 5 and a top beam 9a spanning between the cylinder unit 9b and the supports 7. The cylinder unit 9b includes, for example, an electric cylinder. The motor 62 is a motor, such as a servo motor, that enables vertical position control of the support 7 (lifting body 6).

[0028] 1 and 3, the support 7 is disposed on the platform 2, but the frame 8 protrudes forward from the platform 2. As shown in FIG. 1, the horizontal moving body 3 is positioned at a first horizontal position P Ｘ When the frame 8 is positioned at the second lateral position P1, the frame 8 extends toward the relay position 110a. The front end of the frame 8 is close to the relay position 110a with a predetermined gap therebetween. When the frame 8 is positioned at the second lateral position P2, the frame 8 faces the third receiving portion 205 (or another receiving portion) of the fixed station 200. ＸWhen the frame 8 is positioned at position 2, the frame 8 extends toward the third mounting portion 205 (or another mounting portion). The front end of the frame 8 is close to the third mounting portion 205 (or another mounting portion) with a predetermined gap therebetween. The first arm 20 and the second arm 30 also extend to the same positions as the frame 8 in the front-rear direction.

[0029] Next, the first arm 20, the second arm 30, and the moving device that moves them will be described with reference to Figures 1 and 3 to 6. As shown in Figures 1, 3, and 4, the first arm 20 has two claws 23 that abut against the flange underside (supported portion) 11 of a certain tray 10 to support the tray 10. The tray 10 includes a pair of flange portions 14 (see Figure 11(a)) on both sides thereof, and the claws 23 abut against the flange undersides 11 of these flange portions 14. When the transfer device 1 transports the tray stack Ta, the first arm 20 supports the lowest tray 10L (see Figure 11(a)) of the tray stack Ta.

[0030] The first arm 20 has a first arm base 21 extending in the left-right and front-back directions, a pair of left and right first holding and driving units 22 provided on the first arm base 21, and claws 23 held by each of the first holding and driving units 22.

[0031] The transfer device 1 includes a first advance / retract device M3a that moves the first arm 20 forward and backward relative to the lateral mover 3 (the lifting body 6 or the frame 8). The first advance / retract device M3a is integrated with the frame 8. The first advance / retract device M3a has a pair of guide rails 42 extending parallel to each other in the front-rear direction, one cylinder unit 41 extending in the front-rear direction at a midpoint between the guide rails 42, and a motor 43 provided in the cylinder unit 41. The pair of guide rails 42 support the first arm base 21 of the first arm 20 and guide the first arm base 21. The cylinder unit 41 includes, for example, an electric cylinder. The motor 43 is a motor that enables position control of the first arm base 21 (first arm 20) in the front-rear direction, and is, for example, a servo motor.

[0032] As shown in FIG. 4, the first arm 20 is moved to a rear initial position P Ｙa1 and the advanced position P where the claw 23 abuts against the flange lower surface 11 of the tray 10. Ｙ a2. Ｙ a1 and advance position P Ｙ a2 is not an absolute position in space, but a relative position in the front-to-rear direction with respect to the frame 8. As shown in Figures 11(a) and 11(b), the first holding drive unit 22 moves the pair of claws 23 in a direction that moves them apart from each other (opening operation) and in a direction that moves them closer to each other (closing operation). The movement of the pair of claws 23 changes the distance between the claws 23, which are always maintained in a parallel positional relationship.

[0033] As shown in Figures 3, 4, and 5, the second arm 30 is positioned below the first arm 20. The second arm 30 has two claws 33 that abut against the left and right side surfaces 16 (see Figure 9(b)) of a tray 10 to position (center) the tray 10. As described above, the positions of the trays 10 in the stack T in the front-to-rear and left-to-right directions may be slightly shifted based on the loose fit between the recessed portions 17 and the bottom surfaces 18. In other words, the 15 trays 10 shown in Figure 2 are not necessarily aligned strictly. When the transfer device 1 attempts to stack the tray stack Ta on the stack T, the second arm 30 positions (centers) the top tray 10H (see Figure 9(b)). The two claws 33 of the second arm 30 can abut against the side surfaces 16 of the top tray 10H of the stack T.

[0034] The second arm 30 has a second arm base 31 extending in the left-right and front-back directions, a pair of left and right second holding and driving units 32 provided on the second arm base 31, and claws 33 held by each of the second holding and driving units 32.

[0035] The transfer device 1 includes a second advance / retract device M3b that moves the second arm 30 forward and backward relative to the lateral mover 3 (the lifting body 6 or the frame 8). The second advance / retract device M3b is integrated with the frame 8. The second advance / retract device M3b includes a pair of guide rails 52 extending parallel to each other in the front-rear direction, one cylinder unit (not shown) extending in the front-rear direction at an intermediate position between the guide rails 52, and a motor (not shown) provided in the cylinder unit. The pair of guide rails 52 support the second arm base 31 of the second arm 30 and guide the second arm base 31. The cylinder unit includes, for example, an electric cylinder. The motor is a motor that enables position control of the second arm base 31 (second arm 30) in the front-rear direction, and is, for example, a servo motor.

[0036] As shown in FIGS. 4 and 5, the second arm 30 is moved to a rear initial position P Ｙ b1 and an advanced position P where the claw 33 is positioned in the space 13 under the flange of the tray 10. Ｙ b2. Ｙ b1 and advance position P Ｙ b2 is not an absolute position in space, but a relative position in the front-to-rear direction with respect to the frame 8. As shown in Figures 9(a) and 9(b), the second holding drive unit 32 moves the pair of claws 33 in a direction that moves them apart from each other (opening operation) and in a direction that moves them closer to each other (closing operation). The movement of the pair of claws 33 changes the distance between the claws 33, which are always maintained in a parallel positional relationship.

[0037] The second forward / backward movement device M3b moves the second arm 30 separately and independently from the movement of the first arm 20 by the first forward / backward movement device M3a. As described above, the first arm 20 and the second arm 30 move together in the left-right and up-down directions. However, the first arm 20 and the second arm 30 move independently and separately in the front-rear direction.

[0038] The transfer device 1 includes a controller 60 that controls the left-right movement device M1, the lifting / lowering device M2, the first forward / backward movement device M3a, and the second forward / backward movement device M3b. The controller 60 is a control device that controls each part of the transfer device 1. The controller 60 is a computer that includes a read-only memory (ROM) in which programs and the like are stored, a random access memory (RAM) in which data is temporarily stored, a storage medium such as a hard disk drive (HDD), a processor such as a central processing unit (CPU), and a communication circuit such as a wireless LAN. The controller 60 is capable of communicating information with a higher-level controller (not shown) via wired or wireless communication.

[0039] The controller 60 controls the left-right movement device M1, the lifting / lowering device M2, the first forward / backward movement device M3a, and the second forward / backward movement device M3b based on commands from, for example, a higher-level controller. Through these controls, the controller 60 moves the first arm 20 and the second arm 30 so as to stack the stack of trays Ta on the stack T placed on the pallet PL of the fixed station 200 (stacking control). The controller 60 also controls the first arm 20 and the second arm 30 so as to remove, in one go, the upper multiple tiers of trays 10 (e.g., five tiers equivalent to the stack of trays Ta) of the stack T from the stack T placed on the pallet PL of the fixed station 200 (de-tiering control). In other words, the controller 60 moves the first arm 20 and the second arm 30 so as to remove all trays 10 above any one of the stacks T (for example, the fifth tray 10 from the top of the stack T) from the stack T placed on the pallet PL of the fixed station 200 at once.

[0040] Here, the configuration of the claws 23 and 33 for reliable position control of the first arm 20 and the second arm 30 will be described. As shown in FIG. 6( a), the claw 23 includes a base end 23a held by the first holding / driving unit 22, a horizontal extension 23b extending at a position lower than the base end 23a, and an inclined portion 23f between the base end 23a and the horizontal extension 23b. The horizontal extension 23b has a rectangular cross section that is long in the vertical direction (see FIG. 11( a)). A sensor (first sensor) 26 is provided at the tip 23c of the horizontal extension 23b. The sensor 26 is, for example, a photoelectric sensor that emits light forward and detects the reflected light.

[0041] As shown in Fig. 6(b), the claw 33 includes a base end 33a held by the second holding / driving unit 32 and a horizontal extension 33b extending forward from the base end 33a. The horizontal extension 33b has a rectangular cross section that is long in the left-right direction (see Fig. 9(b)). A sensor 36 is provided at a tip end 33c of the horizontal extension 33b. The sensor 36 is, for example, a photoelectric sensor that emits light forward and detects the reflected light.

[0042] The controller 60 receives a signal from the sensor 26 and detects both or either the position of the flange undersurface 11 of any one tray 10 in the stack T (or the position of the under-flange space 13) and the number of trays in the stack T. The function of the sensor 36 is the same as that of the sensor 26. The sensor 26 may be attached to a location other than the tip end 23c (for example, the base end 23a, etc.). The sensor 36 may be attached to a location other than the tip end 33c (for example, the base end 33a, etc.).

[0043] Next, an example of transporting a stack of trays Ta by the transfer device 1 will be described with reference to Figures 4 and 7 to 11. In the following description, an example of stacking the stack of trays Ta on a stack T placed on the third placement section 205 on the fixed station 200 will be described. Note that in Figures 7, 8, and 10, stacks T (stacks T on the first placement section 203 and the second placement section 204) that are not the target of stacking (stacking) the stack of trays Ta are marked with crossed diagonal lines for ease of reference in each figure. Also, a state in which no stack of trays T is present on the fourth placement section 206 is shown.

[0044] 4, the controller 60 controls the left-right moving device M1, the lifting / lowering device M2, and the first forward / backward moving device M3a to support and lift the tray stack Ta placed at the relay position 110a. Ｚ 1, the first arm 20 is at the advanced position P Ｙ a2. After that, the frame 8 advances to the trade-in position P Ｚ 7, the controller 60 controls the left-right moving device M1 to transport the tray stack Ta to the left. Ｘ 2 (see FIG. 1), the second arm 30 is in the initial position P Ｙ Waiting at b1.

[0045] Next, as shown in FIG. 8, the controller 60 controls the lateral moving body 3 to move to the second lateral position P Ｘ 2, the controller 60 controls the lifting / lowering device M2 and the second forward / backward moving device M3b to insert the claws 33 into the under-flange space 13 of the uppermost tray 10H of the stack T placed on the third placement section 205, for example. Most of the horizontal extensions 33b are positioned within the under-flange space 13. At this time, as shown in FIG. 9( a), the pair of horizontal extensions 33b are spaced apart from the side surface 16. After stopping the forward movement of the second arm 30, the controller 60 controls the second holding drive unit 32 to bring the pair of horizontal extensions 33b closer to each other. The controller 60 stores the correct position (left-right and front-rear positions) of the tray 10 on the third placement section 205 based on the positioning guides on the pallet PL, etc., and moves the lateral mover 3 to the second lateral position P so that the correct position coincides with the position of the second arm 30 (lateral mover 3). Ｘ2. The controller 60 stops the closing operation of the claws 33 at a timing when the left-right distance between the pair of horizontally extending portions 33b substantially matches the distance between the pair of side surfaces 16 (the width of the tray 10 below the flange) (see FIG. 9B). As a result, the claws 33 come into contact with the side surfaces 16, and the topmost tray 10H of the stack T is aligned (centered). When the topmost tray 10H moves left-right, one or more topmost trays 10H below it are also influenced by this movement and move closer to their normal positions.

[0046] In addition, triangular protrusions or the like may be provided on the inner surfaces where the pair of horizontal extension portions 33b face each other, and depressions, recesses, grooves, or the like may be provided at positions corresponding to the protrusions or the like on the side surface 16 of the tray 10, so that alignment in the front-to-back direction (centering) can be performed in conjunction with alignment in the left-to-right direction.

[0047] As described above, in this embodiment, the controller 60 moves the second arm 30 to align the top tray 10H of the stack T before stacking the tray stack Ta on the stack T.

[0048] Subsequently, as shown in FIG. 10, the controller 60 controls the first forward / backward movement device M3a to move the first arm 20 to the advanced position P Ｙa2, and position the tray stack Ta directly above the stack T. At this time, as shown in FIG. 11( a), a gap G exists between the top surface 15 of the top tray 10H of the stack T and the bottom surface 18 of the bottom tray 10L of the tray stack Ta. Because the alignment of the top tray 10H has been completed, the position of the recessed portion 17 of the top tray 10H overlaps the position of the bottom surface 18 of the bottom tray 10L in a plan view. The controller 60 then controls the lifting / lowering device M2 to slightly lower the first arm 20 and the second arm 30. Thereafter, as shown in FIG. 11( b), the pair of claws 23 and the pair of claws 33 open, causing them to move away from the pair of side surfaces 16. With the tray stack Ta stacked on the stack T, the horizontal extension portion 23b and the horizontal extension portion 33b are located within the range of the under-flange space 13 and do not interfere with the flange portion 14. Thereafter, the controller 60 controls the first advance / retract device M3a and the second advance / retract device M3b to retract the first arm 20 and the second arm 30 rearward.

[0049] In the case of step-down control, the controller 60 controls only the left-right moving device M1, the lifting / lowering device M2, and the first forward / backward device M3a. The second forward / backward device M3b is not controlled, and the second arm 30 is kept at the initial position P Ｙ b1 (see FIG. 4). The controller 60 causes the first arm 20 to perform an operation reverse to the stacking control, thereby removing any upper multiple tiers of trays 10 from the stack T in one go. At this time, a signal from the sensor 26 is utilized to ensure that the claws 23 are inserted reliably into the under-flange spaces 13 of the targeted trays 10. The controller 60 can remove any number of tiers of trays 10 in one go by appropriately determining the trays 10 into which the claws 23 are to be inserted.

[0050] According to the transfer device 1, the first arm 20 can be raised and lowered and stopped at any height by controlling the lifting / lowering device M2. The first arm 20 can advance its two claws 23 to the position of the flange undersurface 11 of the tray 10 and retract them from the position of the flange undersurface 11 by controlling the first forward / backward moving device M3a. By controlling the first arm 20, which moves on at least two axes, with the controller 60, the transfer device 1 can stack tray stacks Ta in a predetermined position. The number of tray stacks T is not particularly limited, and the number of tray stacks Ta to be stacked is also not particularly limited. The transfer device 1 can also remove multiple trays 10, including any tray 10, from the stack T in a single operation. The first arm 20 may support any tray 10 in the stack T. All trays 10 stacked above the supported tray 10 are removed, including the supported tray 10. Therefore, there is no particular limit to the number of trays 10 that can be removed. Multiple trays 10 can be freely handled within the range of the load capacity and performance of each device.

[0051] Since the transfer device 1 is equipped with the left-right movement device M1, the degree of freedom in layout of the transport system S including other transport devices such as the transfer conveyor 100 and the relay conveyor 110 is improved.

[0052] The uppermost tray 10H is positioned by the second arm 30, so that the posture of the entire stack T can be adjusted. This allows the tray pile Ta to be stacked in a more stable state.

[0053] The controller 60 can accurately grasp the position of the flange undersurface 11 (including the position of the underflange space 13) of any one tray 10 via the first arm 20, and can reliably support that one tray 10. Alternatively, the controller 60 can reliably identify multiple tiers of trays 10 to be removed by grasping the number of tiers in the stack T. For example, it is possible to prevent a situation in which the first arm 20 is moved to a position in the air where no tray 10 is present (a so-called miss).

[0054] The positioning guides of the pallet PL place the bottom tray 10L of the stack T in an appropriate position, so that each tray 10 in the stack T formed on the pallet PL also maintains a relatively appropriate position and posture. Therefore, stacking of tray piles Ta on the stack T and removal of multiple trays 10 from the stack T can be carried out without any problems.

[0055] In the above explanation, we have explained stacking and de-stacking of the third loading section 205 on the front side of the fixed station 200, but the transfer device 1 may also be configured to be able to stack and de-stack the first loading section 203 and the second loading section 204 on the back side as viewed from the transfer device 1.

[0056] Although the embodiments of the present disclosure have been described above, the present invention is not limited to the above embodiments. For example, the left-right movement device M1, the lifting / lowering device M2, the first forward / backward movement device M3a, and the second forward / backward movement device M3b may have known configurations different from those of the devices in the above embodiments. The supported portion of the tray 10 may be a portion other than the flange undersurface 11 that can engage with the claws 23.

[0057] The second arm 30 may be omitted. The left-right movement device M1 may be omitted. In this case, instead of the lateral movement body 3, for example, a rotating body that can rotate around a vertical axis may be provided, and the tray stack Ta may be moved in the lateral direction.

[0058] 1...transfer device, 10...tray, 11...underside of flange (supported portion), 20...first arm, 23...claw, 23c...tip portion, 26...sensor, 30...second arm, 33...claw, 60...controller, 200...fixed station, M1...left-right movement device, M2...lifting and lowering device, M3a...first forward / backward movement device, M3b...second forward / backward movement device, T...stacked body, Ta...tray stack.

Claims

1. A transfer device for transferring multiple tiers of trays, comprising: a first arm having two claws that abut against a supported portion of a tray to support the tray; an advance / retract device for moving the first arm forward and backward; a lifting / lowering device for raising and lowering the first arm; and a controller for controlling the movement of the first arm, wherein the controller controls the advance / retract device and the lifting / lowering device to move the first arm so as to stack the multiple tiers of trays on a stack of trays arranged at a predetermined position, and to move the first arm so as to remove multiple tiers of trays, including any one of the trays in the stack, from the stack in one go.

2. The transfer device according to claim 1, further comprising a left-right movement device for moving the first arm left-right.

3. A transfer device as described in claim 1 or 2, further comprising a second arm positioned below the first arm and having two claws capable of abutting the topmost tray of the stack, and the controller moves the second arm to align the topmost tray before stacking the multiple trays on the stack.

4. A transfer device as described in claim 1 or 2, wherein the first arm includes a sensor provided at the tip of at least one of the claws, and the controller inputs a signal from the sensor to detect at least one of the position of the supported portion of any one of the trays and the number of stages in the stack.

5. A transfer device as described in claim 1 or 2, wherein the stack is placed on a pallet installed at the specified position, and a positioning guide is provided on the upper surface of the pallet to position the bottommost tray of the stack.

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