Workpiece supply device and control method

Abstract

[Problem] To provide a workpiece supply device and a workpiece supply method that can reduce temporary machine stoppages due to loading or unloading work performed by a worker using a hand truck. [Solution] The present invention provides a workpiece supply device 3 that places, in a designated position, a tray 300 from among a plurality of trays 300 onto which a workpiece W is to be transferred by a loader device 2, the workpiece supply device 3 comprising: a plurality of pallets 200 on which is placed a group of trays 300 made up of a stacked plurality of trays 300; a conveyor unit 10 that circulates each of the plurality of pallets 200 along a designated circulation route 100; and a tray changer 20 which is capable of raising and lowering a pallet 200 brought into a first specified area SA1 on the circulation route 100 and which holds the uppermost tray 300 on the raised pallet 200 at a designated position, wherein the tray changer 20 is capable of stacking the tray 300 at the designated position on a pallet 200 in a second specified area SA2 on the circulation route 100.

Description

Work supply device and control method

[0001] The present invention relates to a workpiece supplying device and a control method.

[0002] A known work supply device places the topmost tray of multiple trays stacked in a first specific area at a transfer position where workpieces are transferred to and from a loader device (see, for example, Patent Document 1). The work supply device stacks the trays that have completed the transfer of workpieces to and from the loader device in a second specific area adjacent to the first specific area, and places the next tray in the first specific area at the transfer position.

[0003] Japanese Patent Application Publication No. 6-106442

[0004] Generally, a hand truck is used to transport multiple stacked trays into the first specified area or to transport stacked trays out of the second specified area. For example, when there are no more trays in the first specified area, a worker stacks multiple trays on the hand truck and transports it into the first specified area.

[0005] However, while the worker is carrying in the work, it is difficult to transfer the workpieces, so the work supply device must be temporarily stopped, and therefore the loader device must be temporarily stopped. This problem is not limited to the worker carrying in the workpieces, and the same problem can occur when the worker carries out the tray.

[0006] An object of the present invention is to provide a work supply device and a work supply method that can reduce temporary machine stoppages caused by workers using hand carts to carry in or out work.

[0007] A work supply device according to one aspect of the present invention is a work supply device that places, at a predetermined position, one of a plurality of trays to which a work is transferred by a loader device, and includes a plurality of pallets on which a group of trays, each of which is made up of a plurality of stacked trays, is placed, a conveying unit that circulates each of the plurality of pallets along a predetermined circulation path, and a tray changer that is capable of raising and lowering a pallet brought into a first specific area on the circulation path and holds the topmost tray on the raised pallet at a predetermined position, and the tray changer stacks the tray at the predetermined position on a pallet in a second specific area on the circulation path.

[0008] A control method according to an aspect of the present invention is a control method for a work supply device that places a tray among a plurality of trays, to which a work is transferred by a loader device, at a predetermined position, and the work supply device has a predetermined circulation path and includes circulating a group of trays, each group having a plurality of stacked trays, along the circulation path, raising the topmost tray in a first specific area on the circulation path and holding it at a predetermined position, and when the transfer of the work is completed, stacking the tray at the predetermined position in a second specific area on the circulation path.

[0009] A workpiece supplying device and a control method thereof according to an embodiment of the present invention circulate a group of multiple trays along a predetermined circulation path 100 and hold the top tray on a pallet brought into a first specific area on the circulation path in a predetermined position. The workpiece supplying device then stacks the trays in the predetermined position on a pallet in a second specific area SA2 on the circulation path. This configuration allows trays to be brought into the first specific area and taken out from the second specific area multiple times without using a hand truck, reducing temporary machine stoppages due to workers' loading and unloading operations. Furthermore, trays of material can be inserted midway into the conveying section, significantly reducing temporary machine stoppages due to workers' loading and unloading operations.

[0010] Furthermore, in the work supply device according to the above aspect, the transfer of the work may include a first operation in which a loader device removes a workpiece material before processing from a tray at a predetermined position, and a second operation in which the loader device places a completed workpiece after processing in the position on the tray where the material removed in the first operation was placed.

[0011] In the workpiece supply device according to the above aspect, the tray changer may stack trays on which the transfer of the workpieces has been completed on the pallet in the second specific area. This configuration can reduce temporary machine stoppages due to the operation of loading trays before the transfer of the workpieces and unloading trays on which the transfer of the workpieces has been completed.

[0012] In addition, in the work supply device according to the above aspect, when all of the pallets in the first specific area are stacked in the second specific area, the transport unit may circulate each of the multiple pallets, thereby transporting the group of trays in the second specific area out of the second specific area and transporting a new group of trays into the first specific area.

[0013] In the workpiece supply device according to the above aspect, the tray changer may include a first lifter capable of raising and lowering the first pallet, which is a pallet in the first specific area, a second lifter capable of raising and lowering the second pallet, which is a pallet in the second specific area, a holding unit that holds the top tray on the first pallet in a predetermined position when the first pallet is raised, and a movement control unit that slides the holding unit between the first specific area and the second specific area, and the movement control unit may slide the holding unit, which holds the tray in the predetermined position, from the first specific area to the second specific area when the transfer of the workpiece is completed. Also, the tray changer may raise the second pallet using the second lifter, and stack the tray held by the holding unit that has slid to the second specific area on the second pallet.

[0014] 14 is a schematic configuration diagram of a work transport system according to the present embodiment. FIG. 15 is a view of the work supply device according to the present embodiment as seen from the Z direction. FIG. 16 is a view of the work supply device according to the present embodiment as seen from the X direction. FIG. 17 is a view of the work supply device according to the present embodiment as seen from the Y direction. FIG. 18 is a flowchart of the operation of the work supply device 3 according to the present embodiment. FIG. 19 is a view showing an initial state according to the present embodiment. FIG. 19 is a view showing a state in which the pallet is raised by the first lifter according to the present embodiment. FIG. 20 is a view showing a state in which the first pallet is lowered with the topmost tray held according to the present embodiment. FIG. 21 is a view showing a state in which works are being transferred between the topmost tray and the loader device according to the present embodiment. FIG. 22 is a view showing a state in which the holding unit holding a completed tray according to the present embodiment has moved above a second specific area. FIG. 23 is a view showing a state in which the second pallet is raised and the completed tray is supported from below by the second pallet according to the present embodiment. FIG. 24 is a view showing a state in which the second pallet is lowered according to the present embodiment. FIG. 25 is a schematic view showing a state in which all trays on the first pallet according to the present embodiment are stacked on the second pallet. FIG. 26 is a perspective view of the work supply device in the state shown in FIG. 13. FIG. 27 is a perspective view of the work supply device after pallet circulation according to the present embodiment. FIG. 28 is a view showing the case in which the transport unit according to the present embodiment is in an initial state. 17 is a diagram showing a state in which all trays placed on the pallet according to the present embodiment have been stacked on the pallet that is the final pallet. FIG. 18 is a diagram showing a state after the pallets have been circulated from the state shown in FIG. 17. FIG. 19 is a diagram showing a state in which the final pallet according to the present embodiment has been arranged in a first specific area.

[0015] The present invention will be described below through embodiments, but the following embodiments do not limit the scope of the invention. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. In the drawings, identical or similar parts may be designated by the same reference numerals, and redundant explanations may be omitted. Furthermore, the shapes and sizes of elements in the drawings may be exaggerated for clarity, and may differ in shape and size from the actual product.

[0016] In Figure 1, the directions in the figure may be explained using an XYZ coordinate system. In the XYZ coordinate system, a plane parallel to the horizontal plane is the XY plane. One direction in this XY plane is referred to as the X direction, and the direction perpendicular to the X direction is referred to as the Y direction. Furthermore, the direction perpendicular to the XY plane is referred to as the Z direction.

[0017] 1 is a schematic diagram of a workpiece transport system WTS according to this embodiment. As shown in FIG. 1, the workpiece transport system WTS includes a machine tool 1, a loader device 2, and a workpiece supply device 3.

[0018] The machine tool 1 processes a workpiece W. The shape of the workpiece W is not particularly limited. The machine tool 1 is not particularly limited as long as it processes the workpiece W, and is, for example, a lathe. The workpiece W processed by the machine tool 1 (the workpiece W before processing) may be referred to as a "raw material W1." Furthermore, the workpiece W after processing by the machine tool 1 may be referred to as a "finished product W2."

[0019] The loader device 2 transports the raw material W1 stored in the work supply device 3 to the machine tool 1. The loader device 2 also receives the work W machined by the machine tool 1, i.e., the finished product W2, from the machine tool 1 and transports it to the work supply device 3.

[0020] 1 , the machine tool 1 and the workpiece supply device 3 are arranged side by side along the X direction, and the loader device 2 has a loader head 21 that is movable in the X direction. The loader head 21 has a loader chuck 22 that grips the workpiece W. The loader chuck 22 has a mechanism for gripping the workpiece W. The loader device 2 grips a material W1 stored in the workpiece supply device 3 with the loader chuck 22 and transports it to the machine tool 1. The loader device 2 also grips a finished product W2 with the loader chuck 22 and transports it from the machine tool 1 to the workpiece supply device 3.

[0021] The work supply device 3 stores raw materials W1 and finished products W2. Fig. 2 is a view of the work supply device 3 according to this embodiment as seen from the Z direction. Fig. 3 is a view of the work supply device 3 according to this embodiment as seen from the X direction. Fig. 4 is a view of the work supply device 3 according to this embodiment as seen from the Y direction. The work supply device 3 includes, for example, a transport unit 10 and a tray changer 20.

[0022] As shown in FIG. 2 , the conveying unit 10 has a circulation path 100 along which each of the multiple pallets 200 is circulated. The circulation path 100 is formed, for example, along a horizontal plane (XY plane). That is, the conveying unit 10 circulates each of the multiple pallets 200 horizontally along the circulation path 100. Note that the circulation path 100 does not necessarily have to be formed along a horizontal plane, and may be, for example, a path for circulating in a vertical direction. As an example, the conveying unit 10 shown in the figure circulates each of the multiple pallets 200 clockwise. However, the direction in which the pallets 200 are circulated may also be counterclockwise. As an example, the conveying unit 10 shown in the figure has 14 pallets 200a to 200n and circulates each of the pallets 200a to 200n clockwise.

[0023] A single tray 300 or multiple stacked trays 300 can be placed on the pallet 200. The trays 300 can be placed on the pallet 200 by, for example, a worker, or mechanically using a robot or the like. Note that multiple trays 300 stacked on one pallet 200 may be collectively referred to as a "tray group 210." Multiple workpieces W are placed on each tray 300. In the example shown in FIG. 1, a maximum of six workpieces W can be placed on one tray 300.

[0024] As shown in FIG. 1 , when a group of trays 210 is placed on a pallet 200, the conveying unit 10 can circulate the plurality of tray groups 210 along a circulation path 100 by circulating each of the plurality of pallets 200 along the conveying unit 10. The conveying unit 10 is, for example, a conveyor. When the conveying unit 10 is a conveyor, the conveyor may be a belt conveyor, a roller conveyor, or a chain conveyor. The conveying unit 10 is only required to be able to continuously convey the pallets 200 along the circulation path 100, and the conveying method is not particularly limited.

[0025] The tray changer 20 includes a first lifter 30 , a holding unit 31 , a movement control unit 32 , and a second lifter 33 .

[0026] The first lifter 30 can raise and lower the pallet 200 (hereinafter referred to as the "first pallet") in the first specific area SA1 on the circulation path 100. When one or more trays 300 are placed on the pallet 200 in the first specific area SA1, the tray changer 20 raises and lowers the pallet 200, thereby raising and lowering the one or more trays 300.

[0027] The first lifter 30 includes, for example, a plurality of expandable members 311 and a lifting / lowering drive unit 312. The expandable members 311 are attached to the first pallet and are expandable and scalable in the up and down directions. The lifting / lowering drive unit 312 extends and retracts the expandable members 311. The lifting / lowering drive unit 312 raises the first pallet by extending the expandable members 311. The lifting / lowering drive unit 312 lowers the first pallet by contracting the expandable members 311. The lifting / lowering drive unit 312 can be, for example, a hydraulic cylinder, a hydraulic motor, an electric cylinder, an electric motor, or the like. However, the first lifter 30 is not limited thereto, and any configuration may be used as long as it is capable of raising and lowering the first pallet.

[0028] When the first pallet is raised, the holder 31 holds the top tray 300 placed on the first pallet at the transfer position DP. When only one tray 300 is placed on the first pallet, that tray 300 corresponds to the top tray 300.

[0029] For example, the holding unit 31 has a pair of holding members 40. The pair of holding members 40 are attached at preset positions. When the first pallet is raised to the uppermost position, the pair of holding members 40 move toward each other, so that the pair of holding members 40 come into contact with and hold the top tray 300. This causes the top tray 300 to be held at the transfer position DP. The transfer position DP is the position of the tray 300 where the workpiece W is transferred by the loader device 2. In other words, the loader device 2 transfers the workpiece W to the tray 300 located at the transfer position DP.

[0030] The transfer of the workpiece W between the tray 300 at the transfer position DP and the loader device 2 is either or both of removing the raw material W1 from the tray 300 and placing the finished product W2 on the tray 300. When placing the finished product W2 on the tray 300 at the transfer position DP, the loader device 2 may place the finished product W2 at the position where the raw material W1 was removed.

[0031] The transfer of the workpieces W will be described with reference to Fig. 1. Fig. 1 shows a state in which the loader device 2 has removed the material W1 placed on the tray 300. In the initial state before the transfer of the workpieces W, only the material W1 is accommodated in each tray 300.

[0032] When the loader device 2 starts to transfer the workpiece W, it first removes the material W1 placed at position Pt on the tray 300 (first operation). The loader device 2 transports the material W1 removed in the first operation to the machine tool 1. The loader device 2 then delivers the material W1 to the machine tool 1, and receives the workpiece W that the machine tool 1 has been machining until just now, i.e., the finished product W2.

[0033] When the loader device 2 receives the finished product W2, it transports it to the work supply device 3 and places the finished product W2 at position Pt (second operation). That is, when the loader device 2 removes one material W1 from the tray 300 in the first operation, the position Pt where the material W1 was placed becomes vacant, so the loader device 2 performs a second operation to return the finished product W2 to that position Pt. As a result, in the tray 300 held at the transfer position DP, the materials W1 are removed one by one by the loader device 2, and the finished products W2 are placed one by one. As a result, all of the workpieces W in the tray 300 held at the transfer position DP are eventually replaced with the finished products W2. When all of the workpieces W in the tray 300 held at the transfer position DP have been replaced with the finished products W2, the transfer of the workpieces W between the tray 300 and the loader device 2 is completed.

[0034] The movement control unit 32 slides the holding unit 31 between the first specific area SA1 and the second specific area SA2. The second specific area SA2 is an area on the circulation path 100 and is different from the first specific area SA1. In the example shown in FIG. 1 , the second specific area SA2 is an area adjacent to the first specific area SA1. For example, a rail is provided along which the holding unit 31 can slide over the distance between the first specific area SA1 and the second specific area SA2. When the transfer of the workpiece W is complete, the movement control unit 32 slides the holding unit 31, which is holding the tray 300 at the transfer position DP, along the rail from the first specific area SA1 to the second specific area SA2. As a result, the tray 300, for which the transfer of the workpiece W has been completed, moves from the first specific area SA1 to the second specific area SA2.

[0035] The second lifter 33 is capable of raising and lowering the pallet 200 (hereinafter referred to as the "second pallet") in the second specific area SA2 on the circulation path 100. By raising the second pallet, the second lifter 33 stacks the trays 300 held by the holders 31 that have slid into the second specific area SA2 on the second pallet. In other words, the trays 300 that have completed the transfer of the workpieces W are stacked on the second pallet. The configuration of the second lifter 33 is, for example, the same as that of the first lifter 30.

[0036] Here, the conveying unit 10 has one or more pallets 200 (hereinafter referred to as "empty pallets") that do not have trays 300 placed on them among the multiple pallets 200. That is, at least one empty pallet is required for the tray changer 20 to stack trays in the second specific area SA2. In the example shown in Figures 1 and 2, pallet 200n is an empty pallet.

[0037] The operation of the work supply device 3 according to this embodiment will be described below with reference to FIGS. 5 to 13. FIG. 5 is a flowchart showing the operation of the work supply device 3 according to this embodiment.

[0038] 6 to 13, the first pallet is pallet 200a and the second pallet is pallet 200n. Also, as shown in Fig. 5, trays 300a, 300b, and 300c are stacked on pallet 200a in this order from the top.

[0039] 6 shows the initial state when pallet 200h is carried into first specific area SA1. In the initial state, pallet 200n in second specific area SA2 is an empty pallet. The tray changer 20 first operates the first lifter 30 from the initial state shown in FIG. 6 to raise the first pallet, which is located at the lowest position (step S101 and FIG. 7).

[0040] The tray changer 20 has, for example, a first sensor (e.g., a photoelectric sensor) that detects when the top tray 300 of the first pallet reaches the transfer position DP when the first pallet is raised. The tray changer 20 raises the first pallet with the first lifter 30 until the tray 300 is detected by the first sensor. In other words, when the first sensor detects the tray 300, the tray changer 20 stops the first lifter 30 from raising the first pallet.

[0041] Next, the tray changer 20 operates the holder 31 to hold the top tray 300a at the transfer position DP (step S102). In other words, the tray changer 20 holds the top tray 300a that has reached the transfer position DP, thereby positioning the top tray 300a at the transfer position DP.

[0042] When the tray changer 20 holds the tray 300a in the holder 31, it operates the first lifter 30 to lower the first pallet (step S103 and FIG. 8). Then, when the first pallet has lowered to the lowest position, the tray changer 20 stops the operation of the first lifter 30.

[0043] When the top tray 300a is held at the transfer position DP and the first pallet is lowered to the lowest position, the workpiece W is transferred between the tray 300a held at the transfer position DP and the loader device 2 (step S104 and FIG. 9).

[0044] For example, in step S104, the loader device 2 uses the loader chuck 22 to remove the material W1 from the tray 300a held at the transfer position DP, and moves the loader head 21 to the machine tool 1 while holding the removed material W1. The loader device 2 then delivers the material W1 to the machine tool 1, and receives from the machine tool 1 the finished product W2 that the machine tool 1 had been machining until recently. After receiving the finished product W2 from the machine tool 1, the loader device 2 moves the loader head 21 to the work supply device 3 and places it on the tray 300a held at the transfer position DP.

[0045] The loader device 2 performs a series of operations of removing the raw materials W1 from the tray 300a held at the transfer position DP, transporting them to the machine tool 1, and placing finished products W2 on the tray 300a, until all the raw materials W1 in the tray 300a are gone. When all the raw materials W1 in the tray 300a held at the transfer position DP are gone, that is, when all the workpieces W in the tray 300a have become finished products W2, the transfer of the workpieces W between the tray 300a and the loader device 2 is completed (step S105).

[0046] When the transfer of the workpiece W between the tray 300a held at the transfer position DP and the loader device 2 is completed, the tray changer 20 moves the holding section 31 holding the tray 300a (hereinafter referred to as the "completed tray") on which the transfer of the workpiece W has been completed, and moves it above the second specific area SA2 (step S106 and Figure 10).

[0047] When the completed tray moves above the second specific area SA2, the tray changer 20 operates the second lifter 33 to raise the second pallet until the second pallet comes into contact with the bottom of the completed tray (step S107 and FIG. 11). That is, the tray changer 20 raises the second pallet so that the second pallet supports the completed tray from below.

[0048] With the completed tray supported from below by the second pallet, the tray changer 20 releases the holding of the completed tray by the holding unit 31, thereby placing the completed tray on the second pallet (step S108). For example, the tray changer 20 releases the holding of the completed tray by pulling the pair of holding members 40 away from each other. When the holding of the completed tray by the holding unit 31 is released, the completed tray is placed on the second pallet.

[0049] In step S108, placing a completed tray on the second pallet includes not only placing the completed tray directly on the second pallet, but also stacking the completed tray on top of another completed tray already placed on the second pallet. In other words, if another completed tray is already placed on the second pallet, the processing of step S108 causes the completed tray held in the holder 31 to be stacked on top of that other completed tray.

[0050] After releasing the holding unit 31 from the holding of the completed tray in step S108, the tray changer 20 operates the second lifter 33 to lower the second pallet to the lowest position (step S109 and FIG. 12). When step S109 is completed, the tray changer 20 returns the holding unit 31 to the first specified area SA1.

[0051] Next, the tray changer 20 determines whether the transfer of the workpieces W to all trays 300 on the first pallet has been completed (step S110). As an example, the tray changer 20 has a first sensor that detects whether a tray is present on the first pallet, and if the first sensor detects a tray 300 on the first pallet, it determines that the transfer of the workpieces W to all trays 300 on the first pallet has not been completed. Also, for example, if the first sensor does not detect a tray 300 on the first pallet, the tray changer 20 determines that the transfer of the workpieces W to all trays 300 on the first pallet has been completed.

[0052] However, without being limited to this, the tray changer 20 may execute the process of step S110 using a second sensor that detects that the number of trays 300 stacked on the second pallet has reached a specified number. For example, when the tray changer 20 detects using the second sensor that the number of trays 300 has reached the specified number, it determines that the transfer of the workpieces W from all trays 300 on the first pallet has been completed. The specified number of trays corresponds to the number of trays 300 stacked on the first pallet. For example, the number of trays 300 stacked on each pallet 200 is standardized to the same number of trays (specified number of trays) in advance.

[0053] If the tray changer 20 has not completed the transfer of the workpieces W from all trays 300 on the first pallet, the tray changer 20 proceeds to the process of step S101. That is, the tray changer 20 repeatedly executes the processes of steps S101 to S109 until all trays 300 on the first pallet are gone.

[0054] 6, the tray changer 20 executes the processes of steps S101 to S109 when the top tray 300 in the first tray is tray 300a, tray 300b, or tray 300c. As a result, as shown in FIGS. 13 and 14, the completed trays are stacked on the second pallet in the order of tray 300a, tray 300b, and tray 300c from the bottom.

[0055] If the tray changer 20 determines in step S110 that the transfer of the workpieces W to all trays 300 on the first pallet has been completed, it determines whether any pallets 200 before the transfer of the workpieces W (hereinafter referred to as "unprocessed pallets") remain on the circulation path 100 (step S111). An unprocessed pallet is a pallet on which a tray group 210 before the transfer of the workpieces W, i.e., a tray group 210 containing only the material W1, is placed. The tray changer 20 determines, for example, in step S111, whether the last pallet has been detected. If the tray changer 20 detects the last pallet, it determines that no unprocessed pallets remain on the circulation path 100. If the tray changer 20 does not detect the last pallet, it determines that no unprocessed pallets remain on the circulation path 100. The last pallet is set to, for example, the empty pallet described above. For example, the work supply device 3 may have a detection sensor 50 for detecting the last pallet among the multiple pallets 200.

[0056] In step S111, if the tray changer 20 determines that an unprocessed pallet remains on the circulation path 100, it sends a signal indicating this to the transport unit 10. Upon receiving this signal, the transport unit 10 executes a circulation operation to circulate each of the multiple pallets 200 by one pallet (step S112). For example, in step S112, the transport unit 10 executes a circulation operation to advance each of the multiple pallets 200 by one pallet in the circulation direction from the state shown in FIG. 14. As a result, the transport unit 10 places pallet 200b in the first specific area SA1 and pallet 200a in the second specific area SA2, as shown in FIG. 15.

[0057] The work supply device 3 repeatedly executes the processes of steps S101 to S112 until it is determined in step S111 that no unprocessed pallets remain on the circulation path 100. If it is determined in step S111 that no unprocessed pallets remain on the circulation path 100, the work supply device 3 determines that the transfer of all works W has been completed, stops the operation of the entire work transport system WTS, and completes the process shown in FIG.

[0058] A specific example of a method for detecting the final pallet is described below. FIGS. 16 to 19 are diagrams illustrating the method for detecting the final pallet. The final pallet is provided with a tag 51 that can be detected by a detection sensor 50. The detection sensor 50 is positioned so that it can detect the tag 51 of the final pallet when the final pallet circulates from the first specific area SA1 to the final pallet position PL, which is one pallet behind. The pallet position is the stop position of the pallet 200 on the circulation path. "Rear" refers to the direction opposite to the circulation direction. In the example shown in FIG. 16, 14 pallet positions are set. The conveyor unit 10 repeatedly performs a circulation operation of moving each pallet 200 to the next pallet position, thereby circulating each of the multiple pallets 200 on the circulation path 100. In FIG. 16, the position where pallet 200b stops corresponds to the final pallet position PL, among the 14 pallet positions.

[0059] In Figures 16 to 19, the tray group 210 before the transfer of the work W, i.e., the tray group 210 containing only the material W1, is shown with dots, and the tray group 210 after the transfer, i.e., the tray group 210 containing only the finished product W2, is shown with diagonal lines.

[0060] Fig. 16 is a diagram showing the initial state of the conveying unit 10. The initial state shown in Fig. 16 is a state in which pallet 200a has been carried into first specific area SA1. In the example shown in Fig. 16, the last pallet is set to pallet 200n, which is located one pallet ahead in the clockwise direction from pallet 200a. That is, in the example shown in Fig. 16, the first pallet is pallet 200a, and the second pallet is pallet 200n.

[0061] When the transport unit 10 is set to its initial state, a tag 51 is attached to pallet 200n (last pallet), which is an empty pallet. The detection sensor 50 is pre-positioned in a position where it can detect the tag 51 when the last pallet is located at the last pallet position PL. After the transport unit 10 is set to its initial state and the tag 51 is attached, the tray changer 20 performs a tray exchange operation (steps S101 to S110) from the initial state shown in FIG. 16, and ultimately stacks all of the trays 300 placed on pallet 200a on the last pallet, as shown in FIG. 17.

[0062] When all trays 300 are stacked on pallet 200n, the work supply device 3 executes a circulation operation to circulate each of the multiple pallets 200 by one pallet in the circulation direction. As a result, as shown in Fig. 18, pallet 200n is carried out from the second specific area SA2, pallet 200a is placed in the second specific area SA2, and pallet 200b is placed in the first specific area SA1. In the state shown in Fig. 18, pallet 200n, which is the last pallet, is not placed at the last pallet position PL. Therefore, the last pallet is not detected in step S111, and the tray changer 20 proceeds to step S101.

[0063] The workpiece supply device 3 repeatedly executes the processes of steps S101 to S112 until the detection sensor 50 detects the tag 51. Figure 19 is a diagram showing the state in which the last pallet is placed at the last pallet position PL. As shown in Figure 19, when the last pallet, pallet 200n, is placed at the last pallet position PL, the detection sensor 50 detects the tag 51 attached to pallet 200n and transmits the detection result to the tray changer 20.

[0064] The tray changer 20 executes the tray exchange operation (steps S101 to S110) from the state shown in Fig. 19, and in step S111, determines whether or not the final pallet has been detected based on the detection result received from the detection sensor 50. If the final pallet has been detected, it is determined that the transfer of all the workpieces W has been completed, and the operation of the entire workpiece transport system WTS is stopped, completing the process shown in Fig. 5.

[0065] In this way, the work supply device 3 according to this embodiment circulates a group of multiple trays along a predetermined circulation path 100, and holds one tray 300 on a pallet that has been brought into the first specific area SA1 on the circulation path 100 at the transfer position DP. The work supply device 3 can then stack the tray 300 at the transfer position DP on the pallet 200 in the second specific area SA2 on the circulation path. With this configuration, trays can be brought into the first specific area SA1 and taken out of the second specific area SA2 multiple times without using a handcart, thereby reducing temporary machine stoppages due to workers carrying in or out the trays.

[0066] In addition, the tray 300 of material W1 can be introduced into the conveying section 10 midway without temporarily stopping the operation of the work transport system WTS, such as the transfer of work W between the loader device 2 and the tray 300 and the tray replacement operation.

[0067] For example, while a tray exchange operation or a transfer of the workpieces W is being performed, the worker removes the tray group 210 on the pallet 200 outside the first specific area SA1 and the second specific area SA2, i.e., the tray group 210 containing only the complete products W2, and replaces it with the tray group 210 containing only the plurality of raw materials W1. In other words, while a tray exchange operation or a transfer of the workpieces W is being performed, the worker can insert the tray 300 of the raw materials W1 into the conveying section 10 midway.

[0068] This allows the worker to insert the tray 300 of material W1 into the transport section 10 midway without temporarily stopping the operation of the workpiece transport system WTS, such as the transfer of the workpiece W between the loader device 2 and the tray 300 or the tray replacement operation. As a result, trays can be carried into the first specific area SA1 and carried out from the second specific area SA2 without using a handcart, reducing temporary machine stoppages due to the worker's carrying-in or carrying-out operations.

[0069] The above-described embodiments disclose the following configurations: <Configuration 1> A work supply device 3 that places, among a plurality of trays 300, a tray 300 to which a workpiece W is transferred by a loader device 2 at a predetermined position (transfer position DP), includes: a plurality of pallets 200 on which a group of stacked trays 300 is placed; a transport unit 10 that circulates each of the plurality of pallets 200 along a predetermined circulation path 100; and a tray changer 20 that is capable of raising and lowering the pallet 200 carried into a first specific area SA1 on the circulation path 100 and holds the uppermost tray 300 on the raised pallet 200 in a predetermined position, and the tray changer 20 stacks the tray 300 at the predetermined position on the pallet 200 in a second specific area SA2 on the circulation path 100. <Configuration 2> The workpiece supply device 3 described in Configuration 1, wherein the transfer of the workpiece W includes a first operation in which the loader device 2 removes materials from the tray 300 at a predetermined position, and a second operation in which the loader device 2 places a completed product in the position on the tray where the materials removed in the first operation were placed. <Configuration 3> The tray changer 20 stacks the tray 300, after the transfer of the workpiece W has been completed, on the pallet 200 in the second specific area SA2. <Configuration 4> The workpiece supply device 3 described in any of Configurations 1 to 3, wherein the transport unit 10 circulates each of the multiple pallets 200 when all of the pallets 200 in the first specific area SA1 have been stacked in the second specific area SA2, thereby carrying out the group of trays 300 in the second specific area SA2 from the second specific area SA2 and carrying in a new group of trays 300 into the first specific area SA1.<Configuration 5> The tray changer 20 includes: a first lifter 30 that can raise and lower the first pallet, which is the pallet 200 in the first specific area SA1; a second lifter 33 that can raise and lower the second pallet, which is the pallet 200 in the second specific area SA2; a holding unit 31 that holds the top tray 300 on the first pallet in a predetermined position when the first pallet is raised; and a movement control unit 32 that slides and moves the holding unit between the first specific area SA1 and the second specific area SA2, and when the transfer of the workpiece W is completed, the movement control unit 32 slides and moves the holding unit, which is holding the tray 300 in the predetermined position, from the first specific area SA1 to the second specific area SA2. <Configuration 6> The work supply device 3 according to any one of Configurations 1 to 5, wherein the tray changer 20 raises the second pallet by the second lifter, and stacks the trays 300 held by the holding parts that have slid to the second specific area SA2 on the second pallet. <Configuration 7> A control method for the work supply device 3 that arranges, at a predetermined position, a tray 300 among the plurality of trays 300 to which the work W is to be transferred by the loader device 2, the work supply device 3 having a preset circulation path 100, the control method including: circulating a group of the plurality of stacked trays 300 along the circulation path 100; raising the uppermost tray 300 in the first specific area SA1 on the circulation path 100 and holding it at a predetermined position; and when the transfer of the work W is completed, stacking the tray 300 at the predetermined position in the second specific area SA2 on the circulation path 100.

[0070] One or more of the requirements described in the above-described embodiments may be omitted. Furthermore, the requirements described in the above-described embodiments may be combined as appropriate. Furthermore, the execution order of each procedure shown in this embodiment can be realized in any order as long as the results of a previous procedure are not used in a subsequent procedure. Furthermore, even if the operations in the above-described embodiments are described using terms such as "first," "next," and "subsequently" for convenience, it is not necessary to perform the operations in this order. Furthermore, to the extent permitted by law, the disclosures of Japanese Patent Application No. 2024-002670 and all documents cited in the above-described embodiments are incorporated herein by reference.

[0071] 1...machine tool, 2...loader device, 3...work supply device, 10...transport unit, 20...tray changer, 100...circulation path, 200...pallet, 300...tray

Claims

1. A workpiece supply device for placing, at a predetermined position, a tray among a plurality of trays on which a workpiece is transferred by a loader device, the workpiece supply device comprising: a plurality of pallets on which a group of trays stacked one above the other are placed; a transport unit for circulating each of the plurality of pallets along a predetermined circulation path; and a tray changer capable of ascending and descending a pallet carried into a first specific area on the circulation path, and holding, at the predetermined position, the uppermost tray on the pallet after ascending. The tray changer stacks the tray at the predetermined position on the pallet in a second specific area on the circulation path.

2. The workpiece supply device according to claim 1, wherein the transfer of the workpiece includes: a first operation in which a raw material, which is the workpiece before processing, is taken out from the tray at the predetermined position by the loader device; and a second operation in which a finished product, which is the workpiece after processing, is placed by the loader device at a position on the tray on which the raw material taken out in the first operation was placed.

3. The workpiece supply device according to claim 1, wherein the tray changer stacks the tray for which the transfer of the workpiece has been completed on the pallet in the second specific area.

4. The workpiece supply device according to claim 3, wherein when all the pallets in the first specific area are stacked in the second specific area, the transport unit circulates each of the plurality of pallets to carry out the following operations: carrying out the tray group in the second specific area out of the second specific area, and carrying a new tray group into the first specific area.

5. The tray changer of the workpiece supply device according to claim 1 includes: a first lifter capable of ascending and descending a first pallet, which is a pallet in the first specific area; a second lifter capable of ascending and descending a second pallet, which is a pallet in the second specific area; a holding unit for holding, at the predetermined position, the uppermost tray on the first pallet when the first pallet ascends; and a movement control unit for sliding the holding unit between the first specific area and the second specific area. When the transfer of the workpiece is completed, the movement control unit slides the holding unit holding the tray at the predetermined position from the first specific area to the second specific area.

6. The tracer raises the second pallet by the second lifter, and stacks the trays held by the holding part that has slid to the second specific area on the second pallet. The work supply device according to claim 5.

7. A control method for a work supply device that arranges, at a predetermined position, a tray among a plurality of trays through which the work is transferred by a loader device, the work supply device having a preset circulation path, circulating a plurality of groups of trays stacked with a plurality of the trays along the circulation path, raising the uppermost tray in a first specific area on the circulation path and holding it at the predetermined position, and when the transfer of the work is completed, stacking the tray at the predetermined position in a second specific area on the circulation path. A control method including.

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