Workpiece conveyance device and workpiece conveyance method
The workpiece conveying device addresses the challenge of diverse workpiece handling by using a deformable mat and claws to grip objects securely, enabling stable transport of varied shapes and sizes with rigid components.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- FANUC LTD
- Filing Date
- 2024-12-26
- Publication Date
- 2026-07-02
Smart Images
Figure JP2024046226_02072026_PF_FP_ABST
Abstract
Description
Work transfer device and work transfer method
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[0001] The present disclosure relates to a work transfer device and a transfer method.
[0002] As means for holding or gripping an object to be transferred (hereinafter referred to as a work) and transferring it to a predetermined location, various devices are known. For example, a robot having an end effector provided with a plurality of flexible fingers is well-known.
[0003] Further, a device is known that includes a fixed claw and a movable claw that moves relative to the fixed claw, and hooks the movable claw on the lower surface of the work to take out the work.
[0004] Japanese Patent Application Laid-Open No. 2014-188633, Japanese Patent Application Laid-Open No. 2017-18559
[0005] When it is required to transfer various shaped works with one device, as a means for gripping or holding the work, it is conceivable to use a robot equipped with a suction pad or flexible fingers. However, a suction pad cannot be used when there are irregularities on the surface of the work. Also, flexible fingers are not suitable for transferring, for example, thin film-like works.
[0006] Means for hooking a claw or the like on the bottom surface of the work and lifting the work can transfer the work without being affected by the thickness of the work or the shape of the upper surface. However, in order to hook a claw or the like on the bottom surface of the work, there must be a gap of a size that allows the claw or the like to be inserted between the surface on which the work is placed and the bottom surface of the work. However, it is not easy to provide such a gap for all of a variety of works with different sizes and shapes. [[ID=One aspect of the present disclosure is a workpiece conveying device comprising: a base displaceable in a first direction; at least one finger displaceable in a second direction intersecting the first direction with respect to the base; a claw provided at the tip of the finger; and a flexible matting member located a predetermined distance from the claw in the first direction, wherein the device is configured such that the claw engages with the underside of an object to be conveyed placed on the matting member by moving the finger while the claw is pressed against the matting member.
[0009] Another aspect of the present disclosure is a workpiece transport method comprising: placing an object to be transported on a flexible mat member; moving a finger having a claw at its tip toward the mat member, pressing the claw against the mat member to deform the mat member; moving the finger while the claw is pressed against the mat member to engage the claw with the underside of the object to be transported; and operating the finger to lift the object to be transported and transport it to a predetermined destination.
[0010] This is a schematic diagram of the main parts of a workpiece transfer device according to an embodiment. This figure shows the hand positioned above the workpiece. This figure shows the hand pressed against the matting member. This figure shows the hand with its claws moved to hold the workpiece. This is a schematic diagram of the main parts of a workpiece transfer device according to the first comparative example. This is a schematic diagram of the main parts of a workpiece transfer device according to the second comparative example. This is a schematic diagram of the main parts of a workpiece transfer device according to the third comparative example. This figure shows an example in which a pusher mechanism is provided on the hand. This figure shows the state in which the pusher mechanism is lowered from the state in Figure 4a to grip the workpiece. This figure shows an example in which a locking mechanism is provided on the hand. This figure shows the state in which the flange is lowered from the state in Figure 5a to grip the workpiece. This figure shows an example in which a suction mechanism is further provided on the configuration of Figure 4a. This figure shows the state in which the suction mechanism is lowered from the state in Figure 6a to grip the workpiece. This figure shows an example in which a suction mechanism is further provided on the configuration in Figure 5a to grip the workpiece. This is a perspective view showing an example of the configuration of a hand equipped with the mechanisms described in Figures 4a to 7a. This figure shows the state in which the claws of the hand are moved from the state in Figure 8. This figure shows the modified hand positioned above the workpiece. This figure shows the hand pressed against the matting member. This figure shows the hand with its claws moved to hold the workpiece. This is a schematic diagram of a workpiece transport device according to another embodiment.
[0011] Figure 1 is a schematic diagram of the main parts of a workpiece transfer device according to one embodiment of the present disclosure. The workpiece transfer device 10 has an industrial robot, such as a 6-axis vertical articulated robot, and Figure 1 shows only the robot hand 12 attached to its tip. The robot hand 12 is attached to the tip of a movable part such as a robot arm (not shown) and has a base or flange 14 that is displaceable in a first direction (here substantially vertical direction), and a pair of fingers 16 that are attached to the flange 14 so as to be able to move toward and away from it in a second direction (here substantially horizontal direction) that intersects the first direction, and at least one (preferably both) of the pair of fingers 16 is configured to be movable in the second direction relative to the flange 14. In addition, the tip of each finger 16 is provided with a claw 18 that extends in directions opposite to each other.
[0012] The workpiece transport device 10 has a mat member 20 on which the workpiece W, which is the object to be transported, is placed. The mat member 20 is made of a flexible material such as sponge, rubber, foam, or cloth, at least on its surface, and is configured to bend by an amount that allows the claws 18 to be displaced at least below the lower surface of the workpiece W when pressed against it. The position and shape of the workpiece W can be detected by sensors 19 such as 3D cameras installed in appropriate locations. The transport operation of the workpiece W, which will be described later, is configured to control a robot equipped with a robot hand 12 and can be controlled by a control device (not shown) having a processor and memory. The control device may also be equipped with input devices such as a keyboard or touch panel to receive input from an operator.
[0013] Figures 2a to 2c illustrate the procedure for lifting the workpiece W using the hand 12. First, as shown in Figure 2a, the hand 12 is positioned above the workpiece W, and the pair of fingers 16 are manipulated so that the minimum distance d1 between the two claws 18 is somewhat larger (for example, 1 to 10 mm) than the width d2 of the workpiece W.
[0014] Next, as shown in Figure 2b, the hand 12 is lowered until the claws 18 deform the mat member 20 and are positioned below the lower surface of the workpiece W, thereby forming a recess 21 in the mat member 20. Thus, the depth of the recess 21 is greater than the vertical thickness of the claws 18. Next, as shown in Figure 2c, at least one of the fingers 16 is displaced in a direction that brings them closer together, causing the claws 18 to contact the lower surface of the workpiece W. In the state shown in Figure 2c, the workpiece W is held or gripped by the hand 12, so the workpiece W moves along with the movement of the hand 12, making it possible to transport the workpiece W to a predetermined destination.
[0015] With respect to Figure 2c, whether or not the workpiece W is properly gripped by the claws 18 can be determined by comparing the minimum distance d1 between the two claws 18 with the width d2 of the workpiece W. For example, when d1 is equal to d2, it can be determined that the claws 18 are not engaged with the lower surface of the workpiece W. In this case, the pair of fingers 16 are moved further down along the first direction, and then at least one of the pair of fingers 16 is displaced in the second direction in a direction that brings the two claws 18 closer together. If, as a result, d1 becomes significantly smaller than d2, it can be determined that the claws 18 are engaged with the lower surface of the workpiece W.
[0016] Figures 3a to 3c show the main parts of a workpiece transport device according to a comparative example. The hand 112 has a flange 114 attached to a movable part such as a robot arm (not shown), a pair of fingers 116 that can be displaced in a direction that allows them to move toward and away from each other relative to the flange 114, and claws 118 formed at the tips of each finger 116. In the first comparative example in Figure 3a, the workpiece W is placed on a projection 122 formed on a support member 120, and as shown, the width of the projection 122 is smaller than the width of the workpiece W, so the workpiece W can be transported by appropriately manipulating the fingers 116 to hook the underside of the workpiece W onto the claws 118.
[0017] On the other hand, in the second comparative example shown in Figure 3b, the width of the workpiece W1, which is the object to be conveyed, is smaller than the width of the projection 122, so the claw 118 cannot be brought into contact with the lower surface of the workpiece W1 as in the first comparative example. Therefore, it is difficult to accommodate workpieces of all shapes and sizes with the configurations shown in Figures 3a and 3b.
[0018] Furthermore, in order to transport workpieces with a relatively small width, such as workpiece W1, it is conceivable to form an even smaller projection 123 on the support member 120, as shown in the third comparative example in Figure 3c. However, in the third comparative example, while it becomes possible to transport workpiece W1, long, slender workpieces such as workpiece W2 cannot be supported by the projection 123 alone, and a part of it may tilt so as to come into contact with the support member 120. In this state, it is still difficult to hook both claws 118 onto the underside of workpiece W2.
[0019] In contrast, according to this embodiment, the mat member 20 supporting the workpiece W can be deformed, allowing the claws 18 of the hand 12 to slide under the workpiece W. Therefore, regardless of the size or shape of the workpiece W, it can be held and transported without damaging it. Thus, even workpieces that would be difficult to lift or transport if flexible fingers or suction pads were used as the hand can be properly held and transported. Furthermore, the fingers 16 and claws 18 do not need to be made of flexible material; it is preferable that these components be made of rigid material such as metal.
[0020] The following describes auxiliary means for more stable holding or gripping of the workpiece. First, Figure 4a shows an example in which a pusher mechanism 24 that can be displaced along a first direction is provided on the flange 14 or finger 16. As shown in Figure 4b, the pusher mechanism 24 can engage the claw 18 with the lower surface of the workpiece W, and then be moved downward to contact the upper surface of the workpiece W and apply a constant pressure to the workpiece W. In this way, the claw 18 and the pusher mechanism 24 can cooperate to grip the workpiece W in the vertical direction, thereby preventing problems such as the workpiece W falling off the hand 12 during transport.
[0021] Figure 5a shows an example in which a linear motion mechanism 26 allows the flange 14 to be displaced in a first direction relative to the finger 16, and a locking mechanism 28 fixes the position of the flange 14 relative to the finger 16. As shown in Figure 5b, after engaging the claw 18 with the lower surface of the workpiece W, the flange 14 is lowered so that its lower surface contacts the upper surface of the workpiece W, and the flange 14 can be locked in that state. In this way, the workpiece W can be gripped vertically by the claw 18 and the flange 14, so that problems such as the workpiece W falling off the hand 12 during transport can be prevented. A suitable example of the linear motion mechanism 26 and the locking mechanism 28 is an air cylinder with a locking function.
[0022] Figure 6a shows an example in which a first suction mechanism 30, such as a suction pad that can be displaced in a first direction, is provided on the finger 16. As shown in Figure 6b, the suction pad 30 can be lowered so as to adhere to the upper surface of the workpiece W after engaging the claw 18 with the lower surface of the workpiece W. In this way, the workpiece W can be held in place within the hand 12 so as not to move, thereby preventing problems such as the workpiece W falling out of the hand 12 during transport.
[0023] Figure 7a shows an example in which, in addition to the linear motion mechanism 26 and locking mechanism 28 described in Figure 5a, a second suction mechanism 32, such as a suction pad, is provided on the flange 14. As shown in Figure 7b, by engaging the claw 18 with the lower surface of the workpiece W and then lowering the flange 14, the suction part 32 can be brought into contact with the upper surface of the workpiece W. In this way, the workpiece W can be held in place within the hand 12 so as to prevent problems such as the workpiece W falling out of the hand 12 during transport.
[0024] Figure 8 is a perspective view showing an example configuration of the hand 12 equipped with the various means shown in Figures 4a to 7a, and Figure 9 is a perspective view showing the state in which the fingers 16 are moved toward each other from the state in Figure 8. The flange 14 is provided with a drive mechanism 34 that moves the fingers 16 toward and away from each other, and the drive mechanism 34 has a guide that restricts the direction of movement of the fingers 16 and a motor (not shown) that drives the fingers 16. The pusher mechanism 24 and suction part 30 described above can be provided on the drive mechanism 34 and can be moved together with the fingers 16. On the other hand, the suction part 32 may not be provided on the drive mechanism 34 and may move up and down together with the flange 14. In addition, a linear motion mechanism 26 that moves the flange 14 up and down and a locking mechanism that fixes the flange 14 in a predetermined position are provided, and in the illustrated example, an air cylinder with a locking function is provided.
[0025] In this disclosure, the workpiece W needs to be placed on the mat member 20 before being lifted by the hand 12, but various methods and means can be considered to achieve this state. For example, an operator may manually place the workpiece on the mat member 20, or the workpiece may be transported by a belt conveyor or the like and dropped onto the mat member 20. Once the workpiece is placed on the mat member 20, the position, shape, orientation, etc. of the workpiece can be detected using the sensor 19, etc., and the workpiece can be transported by controlling the hand 12 as described above using the detection results.
[0026] Figures 10a to 10c illustrate the procedure for lifting a workpiece W1 using a modified hand 12a. The hand 12a is attached to the tip of a movable part such as a robot arm (not shown) and has a base or flange 14a that is displaceable in a first direction (here, approximately vertical) and a single finger 16a that is attached to the flange 14a so as to be able to move toward and away from it in a second direction (here, approximately horizontal) that intersects the first direction. The finger 16a is configured to be movable in the second direction relative to the flange 14a. A claw 18a is also provided at the tip of the finger 16a.
[0027] First, as shown in Figure 10a, the hand 12a is positioned above the workpiece W1. Next, as shown in Figure 10b, the hand 12a is lowered until the claws 18a deform the matting member 20 and are positioned below the lower surface of the workpiece W1, thereby forming a recess 21 in the matting member 20. Thus, the depth of the recess 21 is greater than the vertical thickness of the claws 18a. Next, as shown in Figure 10c, the fingers 16a are displaced toward the workpiece W1 so that the claws 18a contact the lower surface of the workpiece W1.
[0028] In the state shown in Figure 10c, the workpiece W1 is positioned on the claw 18a, so as the hand 12a moves, the workpiece W1 also moves, making it possible to transport the workpiece W1 to a predetermined destination. In this way, for example, if the workpiece W1 is relatively small, even a hand 12a with only one finger 16a and claw 18a can transport the workpiece W1 by deforming the mat member 20.
[0029] In the embodiments described above, cases with two fingers (a pair) and one finger were explained, but this disclosure is not limited thereto. For example, it is possible to provide a hand with three fingers, each having a nail, and to configure the three nails to be positioned 120° apart from each other on a single circle, with each nail being able to move toward and away from the center of the circle. Similarly, hands with four or more fingers and nails are also available.
[0030] Figure 11 is a schematic diagram of a workpiece transfer device 50 according to another embodiment. Although the workpiece transfer device 10 was substantially a robot, the disclosure is not limited thereto, and a suspended crane, for example, as shown in Figure 11, can also be applied. Specifically, the workpiece transfer device 50 has a horizontal movement rail 52, a vertical movement mechanism 54 that is movable along the rail 52 and has a tip that is displaceable in the vertical direction, and a hand 56 attached to the tip of the vertical movement mechanism 54. The hand 56, like the hand 12 described above, has a pair of fingers that can move toward and away from each other, and claws formed at the tips of each finger.
[0031] In the embodiment shown in Figure 11, the workpiece W can be placed on a flexible mat member 58 positioned on a conveyor 60, and then, after deforming the mat member 58 using the same procedure as described with reference to Figures 2a to 2c, it can be lifted by a hand 56 and placed in a box 64 positioned on another conveyor 62.
[0032] According to the above-described embodiment, various workpieces of different shapes and sizes (so-called multi-product workpieces) can be lifted and transported using a common device. Therefore, there is no need to prepare different holding means such as hands for each type of workpiece. Furthermore, the fingers and claws that make up the hand do not need to be flexible; on the contrary, by making them from rigid materials, it becomes possible to stably hold the workpiece.
[0033] The following additional information is disclosed regarding the above embodiments and modifications.
[0034] (Note 1) A workpiece conveying device comprising: a base that is displaceable in a first direction; at least one finger that is displaceable with respect to the base in a second direction intersecting the first direction; a claw provided at the tip of the finger; and a flexible matting member located a predetermined distance from the claw in the first direction, wherein the device is configured such that the claw engages with the lower surface of an object to be conveyed placed on the matting member by moving the finger while the claw is pressed against the matting member.
[0035] (Note 2) The workpiece conveying device according to Note 1, wherein the base or the fingers are displaceable in the first direction and have a pusher mechanism configured to grip the object to be conveyed in cooperation with the claws.
[0036] (Note 3) The workpiece transport device according to Note 1 or 2, comprising a linear motion mechanism that allows the base to be displaced in the first direction relative to the finger, and a locking mechanism that fixes the position of the base relative to the finger.
[0037] (Note 4) The workpiece conveying device according to any one of Notes 1 to 3, wherein at least one of the fingers and the base has an adsorption mechanism configured to adsorb to the surface of the object to be conveyed.
[0038] (Note 5) The workpiece conveying device according to Note 1, comprising a pair of fingers attached to the base so as to be able to move toward and away from each other in a second direction intersecting the first direction, and claws provided at the tip of each of the fingers and extending in directions opposite to each other, wherein the claws are pressed against the mat member and at least one of the pair of fingers is moved in a direction in which the pair of fingers move toward each other, thereby engaging the claws with the lower surface of an object to be conveyed placed on the mat member.
[0039] (Note 6) A workpiece transport device according to any one of Notes 1 to 5, comprising a sensor for detecting the position and shape of the object to be transported on the matting member.
[0040] (Note 7) The workpiece transport device according to any one of Notes 1 to 6, wherein the pair of fingers and the nails are made from a rigid material.
[0041] (Note 8) A workpiece transport method comprising: placing an object to be transported on a flexible mat member; moving a finger having a claw at its tip toward the mat member and pressing the claw against the mat member to deform the mat member; moving the finger while the claw is pressed against the mat member to engage the claw with the underside of the object to be transported; and operating the finger to lift the object to be transported and transport it to a predetermined destination.
[0042] 10, 50 Workpiece transport device 12, 56 Hand 14 Flange 16 Finger 18 Claw 19 Sensor 20 Mat component 24 Pusher mechanism 26 Linear motion mechanism 28 Locking mechanism 30, 32 Suction mechanism 34 Drive mechanism 52 Rail 54 Vertical movement mechanism 60, 62 Conveyor 64 Box
Claims
1. A workpiece conveying device comprising: a base that is displaceable in a first direction; at least one finger that is displaceable with respect to the base in a second direction intersecting the first direction; a claw provided at the tip of the finger; and a flexible matting member located a predetermined distance from the claw in the first direction, wherein the device is configured such that the claw engages with the underside of an object to be conveyed placed on the matting member by moving the finger while the claw is pressed against the matting member.
2. The workpiece conveying device according to claim 1, wherein the base or the fingers are displaceable in the first direction and have a pusher mechanism configured to grip the object to be conveyed in cooperation with the claws.
3. The workpiece conveying device according to claim 1 or 2, comprising a linear motion mechanism that allows the base to be displaced in the first direction relative to the finger, and a locking mechanism that fixes the position of the base relative to the finger.
4. The workpiece conveying device according to any one of claims 1 to 3, wherein at least one of the fingers and the base has an adsorption mechanism configured to adsorb to the surface of the object to be conveyed.
5. The workpiece conveying device according to claim 1, comprising: a pair of fingers attached to the base so as to be able to move toward and away from each other in a second direction intersecting the first direction; and claws provided at the tip of each finger and extending in directions opposite to each other, wherein the claws are pressed against the mat member, and at least one of the pair of fingers is moved in a direction in which the pair of fingers move toward each other, thereby engaging the claws with the lower surface of an object to be conveyed placed on the mat member.
6. A workpiece transport device according to any one of claims 1 to 5, comprising a sensor for detecting the position and shape of the object to be transported on the matting member.
7. The workpiece transport device according to any one of claims 1 to 6, wherein the pair of fingers and the nails are made from a rigid material.
8. A workpiece transport method comprising: placing an object to be transported on a flexible mat member; moving a finger having a claw at its tip toward the mat member and pressing the claw against the mat member to deform the mat member; moving the finger while the claw is pressed against the mat member to engage the claw with the underside of the object to be transported; and operating the finger to lift the object to be transported and transport it to a predetermined destination.