Workpiece moving device

Abstract

To provide a workpiece moving device capable of detecting the height of a workpiece without using a captured image of the workpiece.SOLUTION: A workpiece moving device 10 that has a transfer source unit 11 elevating a workpiece group of loaded workpieces W and a conveyance unit 12 transferring the workpiece W in the uppermost stage to another position comprises: workpiece position detecting means 30 which detects the workpiece W in the uppermost stage reaching a height position H as the workpiece group is elevated by the transfer source unit 11, and also detects a workpiece W in a second stage before the workpiece W in the uppermost stage is acquired by the conveyance unit 12 being elevated to the height position H as the workpiece W in the uppermost stage is elevated by the transfer source unit 11 after being acquired; and workpiece height deriving means for detecting the elevation distance L traveled by the group of workpieces from the point at which the elevation of the uppermost workpiece W to the height position H is detected to the point at which the elevation of the second workpiece W to the height position H is detected, and for determining the distance L as the height of the workpiece W located in the uppermost stage.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a workpiece moving device that moves cardboard boxes or the like containing products. [Background technology]

[0002] In a logistics warehouse, cardboard boxes (an example of work) containing products are stacked on different pallets for each product. The required number of cardboard boxes for products requested by the shipping destination are transferred from these pallets to shipping pallets on which no cardboard boxes are stacked. The cardboard boxes are transferred using a support part that descends from above the cardboard box, contacts and supports the cardboard box, and then rises together with the products. The support part supporting the cardboard box moves to the upper side of the shipping pallet and descends to stack the cardboard box on the shipping pallet.

[0003] Conventionally, the distance that a support part is lowered when a cardboard box is loaded onto a shipping pallet is determined based on the height of the cardboard box, etc., which is registered in advance. When equipment is used that raises the shipping pallet when the cardboard boxes supported by the support part are loaded onto the shipping pallet, the distance that the shipping pallet is raised is determined from the height of the cardboard box, etc., which is registered in advance. In equipment that uses the height of the cardboard boxes registered in this way, in addition to registering the height of the cardboard boxes in advance, it is necessary to detect the height of the cardboard boxes to be transferred before starting the work of transferring the cardboard boxes. In contrast, if the system described in Patent Document 1, which detects the height of a cardboard box from an image of the cardboard box, is used, there is no need to register the height of the cardboard box in advance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-36204 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in order to detect the height of a cardboard box from its captured image, it is necessary to introduce image recognition technology, and there is a problem that detection of the height of the cardboard box becomes unstable depending on the image capturing conditions of the cardboard box, etc. This problem is not limited to cardboard boxes, but is the same for other workpieces. The present invention has been made in consideration of the above circumstances, and has an object to provide a work moving device that can detect the height of a work without using a captured image of the work. [Means for solving the problem]

[0006] A work moving device according to a first invention that meets the above-mentioned objective has a source unit that raises and lowers a group of workpieces in which works are stacked in multiple tiers, and a transport unit that acquires the topmost work of the group of workpieces and transfers it to another position, and is equipped with a work position detection means that detects that the work in the topmost tier has been raised to a predetermined height position H due to the raising of the group of works by the source unit, and that the work that was located in the second tier from the top before the transport unit acquired the work in the topmost tier has been raised to height position H by the raising of the source unit after the work in the topmost tier was acquired, and a work height derivation means that detects the distance L that the source unit has raised the group of works from the detection by the work position detection means of the rise of the topmost work to height position H to the detection of the rise of the work located in the second tier to height position H, and detects this distance L as the height of the work that was located in the topmost tier.

[0007] A work moving device according to a second invention that meets the above-mentioned objective has a source unit that raises and lowers a group of workpieces in which works are stacked in multiple tiers, and a transport unit that acquires the top work of the group of works and transfers it to another position by moving it accompanied by lifting.The work moving device is equipped with a work position detection means that detects that the work on the top tier has been raised to a predetermined height position K due to the raising of the group of works by the source unit, and that the work on the top tier has been raised by the height of the work by the transport unit, and a work height derivation means that detects the distance M that the transport unit has raised the work on the top tier from when the work position detection means detects the rise of the work on the top tier to height position K until it detects the rise of the work on the top tier by the transport unit by the height of the work, and detects this distance M as the height of the work that was located on the top tier. Effect of the Invention

[0008] The work moving device of the first invention comprises a work position detection means for detecting that the top work has been raised to a predetermined height position H due to the raising of the work group by the source unit, and that a work that was located in the second tier from the top before the transport unit acquired the work on the top tier has been raised to height position H due to the raising by the source unit after the work on the top tier has been acquired, and a work height derivation means for detecting the distance L by which the source unit has raised the work group from the detection by the work position detection means of the rise of the top work to height position H to the detection of the rise of the work located on the second tier to height position H, and detecting distance L as the height of the work that was located on the top tier.

[0009] In addition, the work moving device of the second invention is equipped with a work position detection means for detecting that the top work has been raised to a predetermined height position K due to the raising of the work group by the source unit, and that the top work has been raised by the transport unit by the height of the work, and a work height derivation means for detecting the distance M that the transport unit has raised the top work from when the work position detection means detects the rise of the top work to height position K to when the transport unit detects the rise of the top work by the height of the top work by the transport unit, and detects the distance M as the height of the work that was located on the top level. Therefore, the workpiece moving devices according to the first and second aspects of the present invention are capable of detecting the height of the workpiece without using a captured image of the workpiece. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram of a workpiece moving device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing the connections of the central control means; [Diagram 3] 1 is an explanatory diagram showing the relationship between the standard height position, the ascent limit height position, and the height position H. FIG. [Figure 4] 13A and 13B are explanatory diagrams showing the manner in which a workpiece is transferred. [Diagram 5] 13A and 13B are explanatory diagrams showing the manner in which a workpiece is transferred. [Figure 6] 13A and 13B are explanatory diagrams showing the manner in which a workpiece is transferred. [Figure 7] FIG. 11 is an explanatory diagram of a workpiece moving device according to a second embodiment of the present invention. [Figure 8] FIG. 2 is a block diagram showing the connections of the central control means; [Figure 9] 13A and 13B are explanatory diagrams showing the manner in which a workpiece is transferred. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, with reference to the attached drawings, an embodiment of the present invention will be described for understanding the present invention. 1, a work moving device 10 according to a first embodiment of the present invention is an apparatus having a source unit 11 that raises and lowers a work group in which works W are stacked in multiple layers, a transport unit 12 that acquires the work W on the top layer of the work group and transfers (moves) it to another position, and a destination unit 13 to which the work W is to be transferred. These will be described in detail below.

[0012] In this embodiment, the workpieces W are cardboard boxes containing products, and as shown in FIG. 1, a plurality of workpieces W are stacked in multiple layers (i.e., a group of workpieces) and placed on a pallet P1. The source unit 11 is equipped with a table 14 on which the workpieces are placed in a state in which they are placed on a pallet P1, and a lifter 15 for raising and lowering the table 14.

[0013] 1 and 2, the lifter 15 has a servo motor 16 (an example of a drive source) which generates a force by actuation to raise the work group placed on the mounting table 14 together with the mounting table 14 while the work group is placed on the pallet P1. The work group is placed on the mounting table 14 together with the pallet P1 on which the work group is placed by a forklift, a belt conveyor, or the like. The height position of the mounting table 14 when the work group is placed on the mounting table 14 is set as a standard height position, and various designs and settings are made so that the lifter 15 can raise the mounting table 14 arranged at the standard height position to the height of the work group or more.

[0014] As shown in Fig. 1, the destination unit 13 is equipped with a mounting table 17 carrying a pallet P2 on which the workpiece W is placed, and a lifter 18 for raising and lowering the mounting table 17. As shown in Figs. 1 and 2, the lifter 18 is equipped with a servo motor 19 for generating a force for lifting the pallet P2 together with the mounting table 17. As shown in Figs. 1 and 2, the source unit 11 and the destination unit 13 are arranged on the same floor surface F with a gap between them.

[0015] The conveying unit 12 has a running vehicle 21 that runs on a guide 20 arranged horizontally above the source unit 11 and the destination unit 13, an air cylinder 23 to which a cylinder tube 22 (base side) is attached to the running vehicle 21, and a suction pad 25 connected to a piston rod 24 (tip side of the air cylinder 23) of the air cylinder 23.

[0016] The piston rod 24 rises together with the suction pad 25 when air is supplied to the cylinder tube 22 from an air compressor (not shown) via a speed controller, and falls together with the suction pad 25 under its own weight when air is exhausted from the cylinder tube 22. Note that, although a single-acting air cylinder 23 is used in this embodiment, it goes without saying that a double-acting air cylinder can also be used, and an electric cylinder or the like may be used instead of the air cylinder 23.

[0017] The suction pad 25 has a suction hole (not shown) that communicates with an air compressor, and when in contact with the upper surface of the workpiece W, the suction hole becomes negative pressure, thereby adsorbing the workpiece W. The workpiece W adsorbed to the suction pad 25 is detached from the workpiece W when the suction hole of the suction pad 25 becomes open to the atmosphere or becomes positive pressure. The traveling vehicle 21 reciprocates along the guide 20, so that the suction pad 25 moves between directly above the source unit 11 and directly above the destination unit 13.

[0018] 2, the vehicle control unit 26, which controls the traveling of the traveling vehicle 21, is connected to a central control means 29 that manages and controls the transfer of the workpiece W, together with an air cylinder control unit 27 that controls the elevation of the servo motors 16, 19 and the piston rod 24, and an adsorption control unit 28 that controls the air pressure of the suction holes of the suction pad 25. The vehicle control unit 26 and the central control means 29 can each be configured by an electronic circuit board, a communication device, etc., and the air cylinder control unit 27 and the adsorption control unit 28 can each be configured by a solenoid valve, an electronic circuit board, etc.

[0019] 1, a photoelectric sensor 30 (an example of a non-contact sensor) fixed to a support member (not shown) is provided near the transfer source unit 11. The light irradiation direction of the photoelectric sensor 30 is adjusted so that it can detect whether or not a workpiece W or other object is present at a height position H in an area (space) where the workpiece group placed on the mounting table 14 rises. In this embodiment, a photoelectric sensor 30 that is long in the horizontal direction is used.

[0020] In this embodiment, the height position H is a position that is higher than the height of the work group with the maximum number of works W (hereinafter referred to as the "height of the maximum work group") plus the height (thickness) of the pallet P1 at the standard height position, and is lower than the height of the pallet P1 plus the limit height position at which the lifter 15 can raise the mounting table 14 (hereinafter also referred to as the "rising limit height position"). For reference, the relationship between the standard height position, the height of the maximum work group, the height of the pallet P1, the height position H, and the upper limit height position is shown in FIG. 3. Therefore, when the work group placed on the pallet P1 is placed on the mounting table 14 arranged at the standard height position, the photoelectric sensor 30 detects that there is no object at the height position H, and further, by raising the mounting table 14 together with the work group by the lifter 15, the photoelectric sensor 30 can detect that there is an object at the height position H (actually, the work W at the top of the work group).

[0021] 2, a work height deriving means 31 capable of acquiring signals from the servo motor 16 and the photoelectric sensor 30 is connected to the servo motor 16 and the photoelectric sensor 30. The work height deriving means 31 can be configured with an AD conversion circuit, an arithmetic circuit, etc., and can calculate the height of each work W constituting the work group based on the signals acquired from the servo motor 16 and the photoelectric sensor 30. The central control means 29 is connected to the work height deriving means 31 and can acquire a signal from the work height deriving means 31.

[0022] Next, a procedure for transferring the workpiece W on the source unit 11 onto the destination unit 13 will be described. With an empty (empty) pallet P2 placed on the mounting table 17 arranged at the same height as the mounting table 14 arranged at the standard height, a group of workpieces placed on the pallet P1 are placed on the mounting table 14 arranged at the standard height, as shown in Fig. 1. At this time, the transport unit 12 is placed above the source unit 11, the suction pad 25 is placed at a position higher than the height position H, and the photoelectric sensor 30 detects that there is no object at the height position H.

[0023] 4(A), the lifter 15 lifts the workpiece group on the pallet P1 together with the mounting table 14. When the workpiece group is raised to a height position H by the operation of the servo motor 16 in response to a command signal sent from the central control means 29 to the servo motor 16, the photoelectric sensor 30 detects the presence of an object at the height position H (i.e., detects that the workpiece W at the top has been raised to the height position H by the raising of the workpiece group by the source unit 11).

[0024] When the central control means 29 receives a signal from the photoelectric sensor 30 that the presence of the topmost workpiece W at height position H has been detected, it stops the servo motor 16 to stop the lifter 15 from raising the group of workpieces and the mounting table 14, and further sends a command signal to the air cylinder control unit 27 to lower the stationary piston rod 24 and suction pad 25 by their own weight, as shown in Fig. 4(B). As a result, the suction pad 25 comes into contact with the top surface of the topmost workpiece W, and by sending a command signal from the central control means 29 to the suction control unit 28, the suction pad 25 adsorbs the topmost workpiece W.

[0025] Thereafter, a command signal is sent from the central control means 29 to the air cylinder control unit 27, and as shown in FIG. 5(A), the piston rod 24 and the suction pad 25 rise together with the workpiece W adsorbed to the suction pad 25, and as shown in FIG. 5(B), a command signal is sent from the central control means 29 to the vehicle control unit 26, and the transport unit 12 moves together with the workpiece W adsorbed to the suction pad 25 from directly above the source unit 11 to directly above the destination unit 13 and stops there.

[0026] While the conveying unit 12 and the suction pad 25 are moving or after they have moved directly above the destination unit 13, a command signal is sent from the central control means 29 to the servo motor 16, and the lifter 15 lifts the group of works on the pallet P1 from which the top work W has been removed, together with the loading table 14, as shown in Figure 6(A).

[0027] As the work group rises, when the current topmost work W of the work group (the work W that was located second from the top before the transport unit 12 acquired the topmost work W) rises to height position H, the photoelectric sensor 30 detects the presence of the current topmost work W at height position H, and the central control means 29 detects the detection by the photoelectric sensor 30 and stops the servo motor 16 to stop the lifter 15 from raising the work group and the mounting table 14.

[0028] Next, the work height derivation means 31 calculates (detects) the distance L by which the lifter 15 (i.e., the source unit 11) lifts the work group from the time when the photoelectric sensor 30 detects that the work W that was originally on the top level (the work W that was on the top level before the transport unit 12 acquired the work W and is currently adsorbed to the suction pad 25) has risen to height position H to the time when it detects that the work W of the current top level (the work W that was originally located on the second level) has risen to height position H, based on the rotation amount (an example of the operating amount) of the servo motor 16, and detects the distance L as the height of the work W that was originally located on the top level and is currently adsorbed to the suction pad 25.

[0029] Then, based on the distance L detected as the height of the workpiece W adsorbed to the suction pad 25, the central control means 29 determines a lift distance D of the mounting table 17 at which the transport unit 12 can lower the suction pad 25 to place (contact) the workpiece W adsorbed to the suction pad 25 on the pallet P2 on the mounting table 17, and sends a command signal to the servo motor 19 to lift the mounting table 17 by the lift distance D, as shown in Figure 6(B).

[0030] While the mounting table 17 is rising or after the mounting table 17 has risen and stopped, the central control means 29 sends a command signal to the air cylinder control unit 27 to lower the suction pad 25 and the workpiece W adsorbed to the suction pad 25 together with the piston rod 24, and place the workpiece W adsorbed to the suction pad 25 on the pallet P2. Here, the height (as well as the width and depth) of each workpiece W that makes up the workpiece group falls within a predetermined range, but is different in the strict sense, so by performing the above-mentioned processing, the workpiece W can be stably placed on the pallet P2 by moving (lowering) within the stroke length of the piston rod 24.

[0031] Thereafter, the central control means 29 sends a command signal to the suction control unit 28, causing the suction pad 25 to release the suction of the workpiece W, and the central control means 29 sends a command signal to the air cylinder control unit 27 and the vehicle control unit 26, causing the suction pad 25 to rise and the transport unit 12 to move from above the destination unit 13 to above the source unit 11.

[0032] Then, the workpiece W that was originally on the second level on the mounting table 14 and is now on the top level is subjected to the same processing (such as measuring the height of the workpiece W) as that performed on the workpiece W that was originally on the first level, and the workpiece W is placed on the mounting table 17 (more precisely, on top of the workpiece W already placed on the pallet P2 on the mounting table 17). By repeating this processing for the other workpieces W, all of the workpieces W that were stacked on the mounting table 14 are finally transferred onto the mounting table 17.

[0033] Next, a work moving device 50 according to a second embodiment of the present invention that measures the height of the work W by a process different from that of the first embodiment will be described. Note that in the work moving device 50, the same components as those in the work moving device 10 are denoted by the same reference numerals and detailed description thereof will be omitted. As shown in Figure 7, the work moving device 50 has a source unit 11 that raises and lowers a group of works, a transport unit 12 that acquires the topmost work W in the group of works and transfers it to another position by moving it upward, and a destination unit 13 to which the work W is to be transferred.

[0034] 8, an air cylinder control unit 52 that controls the elevation of the piston rod 24 is connected to a central control means 51 together with the servo motors 16, 19, the vehicle control unit 26, the suction control unit 28, and the photoelectric sensor 30, and is capable of detecting the elevation length of the piston rod 24. In addition, a work height derivation means 53 that can obtain signals from the servo motor 16 and the photoelectric sensor 30 is connected to the servo motor 16, the photoelectric sensor 30, and the central control means 51.

[0035] The photoelectric sensor 30 provided in each of the work moving devices 10 and 50 is basically the same in terms of the installation position and the function thereof, but the photoelectric sensor 30 of the work moving device 10 detects that the work W in the topmost stage has risen to a height position H due to the rise of the work group by the transfer source unit 11, and that the work W that was located in the second stage from the top before the transfer source unit 12 acquired the work W in the topmost stage has risen to a height position H due to the transfer source unit 11 rising after the work W in the topmost stage was acquired, whereas the photoelectric sensor 30 of the work moving device 50 detects that the work W in the topmost stage has risen to a predetermined height position K due to the rise of the work group by the transfer source unit 11, and that the work W in the topmost stage has been raised by the height of the work W by the transfer unit 12. The work moving device 50 detects the rise of the work W in the topmost stage by the height of the work W when the photoelectric sensor 30 goes from a state where it had detected the presence of an object to no longer detecting the presence of the object.

[0036] As shown in Figures 9(A) and (B), the work height derivation means 53 of the work moving device 50 detects the distance M by which the transport unit 12 has raised the topmost work W from the time the photoelectric sensor 30 detects the rise of the topmost work W to height position K until the transport unit 12 detects the rise of the topmost work W by the height of the work W, and detects this distance M as the height of the work W that was located at the topmost level.

[0037] The rest of the work moving devices 10, 50 are basically the same. For example, when the work moving device 50 lowers the suction pad 25 to place the work W adsorbed to the suction pad 25 on the mounting table 17, the work moving device 50 sends a command signal to the servo motor 19 to raise the mounting table 17 by an elevation distance E determined based on the distance M detected as the height of the work W (the work W located on the top level).

[0038] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and all changes in conditions that do not depart from the gist of the present invention are within the scope of application of the present invention. For example, a range finder that measures the distance from a predetermined position above the source unit to the top of the workpiece group raised by the source unit can be used as the workpiece position detection means instead of a non-contact sensor that detects the presence or absence of an object at height position H. When a non-contact sensor that detects the presence or absence of an object at height position H is used, a sensor other than a photoelectric sensor (for example, a millimeter wave sensor) can be used.

[0039] The transport unit may also be one having a gripping portion for gripping the work (such as a robot hand). The work may be something other than a cardboard box containing a product, such as the product itself or a tool. The distance L (or the distance M) may be derived by measuring the amount of lift of the mounting table (or a member equivalent thereto) of the source unit using a distance sensor or the like. Furthermore, the destination of the workpiece may not be the destination unit, but may be on the floor or a table with a fixed height. In that case, for example, the lowering length of the workpiece when the transport unit supporting the workpiece places the workpiece at the destination is determined based on the detected height of the workpiece. [Explanation of symbols]

[0040] 10: workpiece moving device, 11: source unit, 12: transport unit, 13: destination unit, 14: placement table, 15: lifter, 16: servo motor, 17: placement table, 18: lifter, 19: servo motor, 20: guide, 21: traveling vehicle, 22: cylinder tube, 23: air cylinder, 24: piston rod, 25: suction pad, 26: vehicle control unit, 27: air cylinder control unit, 28: suction control unit, 29: central control means, 30: photoelectric sensor, 31: workpiece height deriving means, 50: workpiece moving device, 51: central control means, 52: air cylinder control unit, 53: workpiece height deriving means, F: floor surface, P1, P2: pallet, W: workpiece

Claims

1. A work moving device having a transfer source unit that raises and lowers a work group in which work pieces are stacked in multiple stages, and a transport unit that acquires the work piece on the top stage of the work group and transfers it to another position, a work position detection means for detecting that the work in the top tier has been raised to a predetermined height position H by the raising of the work group by the source unit, and that the work that was located in the second tier from the top before the transport unit acquired the work in the top tier has been raised to the height position H by the raising of the source unit after the work in the top tier has been acquired; a work height derivation means for detecting the distance L by which the source unit has raised the work group from the time when the work position detection means detects the rise of the topmost work to the height position H to the time when the work located on the second tier is detected to have risen to the height position H, and detecting the distance L as the height of the work located on the top tier.

2. 2. A workpiece moving device according to claim 1, wherein said workpiece position detecting means is a non-contact sensor for detecting whether or not an object is present at said height position H in an area where said group of works is raised.

3. 3. The work moving device according to claim 1 or 2, wherein the source unit has a drive source that generates a force to lift the work group by operation, and the distance L is calculated based on the amount of operation of the drive source.

4. A work moving device having a transfer source unit that raises and lowers a work group in which work pieces are stacked in multiple stages, and a transport unit that acquires the work piece on the top stage of the work group, moves the work piece while being elevated, and transfers the work piece to another position, a work position detection means for detecting that the work in the uppermost stage has been raised to a predetermined height position K by the raising of the work group by the transfer source unit, and that the work in the uppermost stage has been raised by the height of the work by the transport unit; A work moving device characterized in that the work position detection means is equipped with a work height derivation means which detects the distance M by which the transport unit has raised the work on the top tier from the time it detects the rise of the work on the top tier to the height position K until it detects the rise of the work on the top tier by the transport unit by the height of the work, and detects the distance M as the height of the work that was located on the top tier.

5. 5. A work moving device according to claim 4, wherein the work position detection means is a non-contact sensor which detects whether or not an object is present at the height position K of the area where the topmost work is raised by the transport unit.

6. 6. A work moving device as described in claim 4 or 5, characterized in that the transport unit has a drive source that generates a force to lift the work on the uppermost level by operation, and the distance M is calculated based on the amount of operation of the drive source.

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