JP2019209458A - End effector and device - Google Patents

Abstract

To provide an end effector capable of surely performing picking of a workpiece by flexibly coping with a positional relation between fingers and the workpiece.SOLUTION: An end effector 1 includes: fingers 30 and 31 which grip a workpiece 2; a link member 20 which is connected to the fingers 30 and 31; an actuator rod 55 which drives the link member 20; and tension springs 40 and 41 which energize each of the fingers 30 and 31 in a prescribed direction. The fingers 30 and 31 have different link rigidity. Distances L1 and L2 from a connection section 20a between the link member 20 and the actuator rod 55 up to each of connection sections 20b and 20c between the link member 20 and the fingers 30 and 31 take different values.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an end effector that is attached to a robot arm and picks a workpiece, and an apparatus having the end effector.

  In assembly, packing, and distribution processes of industrial products, there are operations for picking workpieces such as parts, finished products, and packed products. As a technique for picking a workpiece, a technique is generally used in which an end effector having a plurality of fingers is attached to a robot arm, the workpiece is gripped by opening and closing the fingers, and picking is performed.

  Here, as a technique for driving a plurality of fingers with a single actuator, a finger driving technique using a link mechanism is known. For example, Patent Document 1 discloses a technique for evenly opening and closing a plurality of fingers with a single actuator using a link mechanism. On the other hand, a technique is known in which a link mechanism that drives a finger is rotatably supported to make the posture of the finger follow the position and shape of a workpiece. For example, Patent Document 2 discloses a technique that enables a workpiece to be gripped at a position deviated from the center of the end effector by rotatably supporting a link member that drives two fingers.

JP 2011-161577 A JP 2012-206215 A

  In Patent Documents 1 and 2, the arrangement of the fingers is substantially point-symmetric or line-symmetric, and the link member is similarly point-symmetric or line-symmetric. In order to open and close the plurality of fingers evenly, the center of the link mechanism or link member is driven by an actuator. Therefore, it is difficult to arrange another mechanism such as a mechanism for assisting gripping of the workpiece at the center of the link member.

  An object of the present invention is to provide an end effector capable of reliably picking a workpiece by flexibly corresponding to the positional relationship between the fingers and the workpiece.

  An end effector according to the present invention includes a plurality of fingers for gripping a workpiece, a link member connected to the plurality of fingers, a driving unit for driving the link member, and each of the plurality of fingers in a predetermined direction. Biasing means for biasing, wherein at least two fingers of the plurality of fingers have different link rigidity, and the link member and the at least one of the link member and the drive means are connected to each other. The distance to each connection part with two fingers takes a different value, It is characterized by the above-mentioned.

  According to the present invention, it is possible to flexibly cope with the positional relationship between the fingers and the workpiece, and to reliably pick the workpiece with the fingers.

It is a schematic sectional drawing of the end effector which concerns on 1st Embodiment. It is sectional drawing which shows the example of arrangement | positioning of the workpiece | work with respect to the end effector of FIG. It is a figure explaining the picking operation | movement of the workpiece | work by the end effector from the state of FIG. It is a schematic sectional drawing of the end effector which concerns on 2nd Embodiment. It is a perspective view of the end effector which concerns on 3rd Embodiment. FIG. 6 is a top view of the end effector of FIG. 5. It is a perspective view of the end effector which concerns on 4th Embodiment. It is a schematic sectional drawing of the end effector which concerns on 5th Embodiment. It is sectional drawing explaining operation | movement of the finger in the end effector of FIG. It is a 1st figure explaining the operation example of the end effector of FIG. It is a 2nd figure explaining the operation example of the end effector of FIG. It is a schematic perspective view of the end effector which concerns on 6th Embodiment.

<First Embodiment>
Hereinafter, an end effector according to a first embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1A and 1B are cross-sectional views showing a first state and a second state of the end effector 1 according to the first embodiment, respectively. For convenience of explanation, as shown in FIGS. 1A and 1B, an X axis, a Y axis, and a Z axis that are orthogonal to each other are defined. The end effector 1 includes a support member including a base portion 10 and support portions 12 and 13, a link member 20, fingers 30 and 31, tension springs 40 and 41, link rods 50 and 51, and an actuator rod 55. The first state in FIG. 1A is a state in which fingers 30 and 31 are opened (open state), and the second state in FIG. 1B is a state in which fingers 30 and 31 are closed (closed state). ).

  The base unit 10 is attached to an end effector moving means such as a robot arm (not shown) via an auxiliary member (not shown), thereby forming a transfer device (picking device). The base portion 10 is provided with a hole through which the link rods 50 and 51 are inserted so that the axial direction of the link rods 50 and 51 is substantially parallel to the Z axis. The finger 30 is supported so as to be rotatable about an axis parallel to the Y axis with respect to the support portion 12. Similarly, the finger 31 is supported so as to be rotatable about an axis parallel to the Y axis with respect to the support portion 13.

  The finger 30 is urged in the arrow A1 direction by a tension spring 40 stretched between the base portion 10 and the finger 30. The finger 31 is urged in the arrow B1 direction by a tension spring 41 stretched between the base portion 10 and the finger 31. That is, the fingers 30 and 31 are urged in the opening direction.

  The fingers 30 and 31 are connected to the link member 20 via link rods 50 and 51, respectively. The connecting portion between the link rod 50 and the finger 30 is configured to be rotatable around an axis parallel to the Y axis. Similarly, the connecting portion between the link rod 51 and the finger 31 is also rotated around an axis parallel to the Y axis. It is configured to be possible. The link rods 50 and 51 are connected to the link member 20 so as to be rotatable around an axis parallel to the Y axis at the connection portions 20b and 20c.

  An actuator rod 55 is connected to the link member 20 so as to be rotatable around an axis parallel to the Y axis at the connection portion 20a. An actuator (not shown) is connected to the actuator rod 55. In accordance with the driving of the actuator, the actuator rod 55 is driven in the driving direction indicated by arrows D and E, that is, the positive direction of the Z axis indicated by arrow D and the negative direction of the Z axis indicated by arrow E.

  When the actuator rod 55 is driven in the Z-axis direction, the fingers 30 and 31 are simultaneously driven via the link member 20 and the link rods 50 and 51. That is, the end effector 1 has a structure in which the two fingers 30 and 31 are driven by one actuator. Specifically, as shown in FIG. 1A, when the actuator rod 55 is driven in the direction of arrow E, the fingers 30 and 31 are driven in the opening directions indicated by arrows A1 and B1, respectively. On the other hand, when the actuator rod 55 is driven in the direction of arrow D as shown in FIG. 1B, the fingers 30 and 31 are driven in the closing directions indicated by arrows A2 and B2, respectively.

  In the end effector 1, the rotational moment around the connection portion of the finger 30 generated by the tension spring 40 (that is, the link stiffness of the finger 30) and the link stiffness of the finger 31 by the tension spring 41 are different. Such a difference in link rigidity is realized by using different tension rigidity (spring constant) for the tension springs 40 and 41 and adjusting the fixing positions of the tension springs 40 and 41 with respect to the fingers 30 and 31, respectively. can do. Due to the difference in link rigidity between the fingers 30 and 31, the force F1 generated in the link rod 50 when the finger 30 is shifted from the open state to the closed state, and the link rod 51 when the finger 31 is moved from the open state to the closed state. Is different from the force F2 generated at the same time.

  In the link member 20, the distance from the connection portion 20 b with the link rod 50 to the connection portion 20 a with the actuator rod 55 is “L1”. In the link member 20, the distance from the connection portion 20 c with the link rod 51 to the connection portion 20 a with the actuator rod 55 is “L2”. In the end effector 1, the distance L1 and the distance L2 take different values. That is, 'L1 ≠ L2'.

  As described above, the relationship of “F1 ≠ F2” is established between the forces F1 and F2, but the relationship of “F1 × L1 = F2 × L2” is established between the forces F1 and F2 and the distances L1 and L2. Is true. That is, the moment of the link member 20 around the connecting portion 20a with the actuator rod 55 is balanced, and the sum of the moments is substantially zero (0). Therefore, when the actuator rod 55 is driven in the Z-axis positive direction (arrow D direction), the link member 20 is maintained in a horizontal posture (a posture parallel to the XY plane). The movement distance in the Z-axis direction is the same. That is, as shown in FIG. 1B, the operation of closing the fingers 30 and 31 evenly is possible.

  Next, an example will be described in which the fingers 30 and 31 are closed unevenly due to external factors. FIG. 2 is a cross-sectional view showing an example of a state in which the workpiece 2 is arranged with respect to the end effector 1 in the first state of FIG. 1 shows a state where the center Ce in the X-axis direction is shifted in the X-axis direction. The position of an axis passing through the center of the link member 20 in the X axis direction and parallel to the Z axis is defined as the center Ce of the end effector 1 in the X axis direction.

  FIG. 3 is a view for explaining the picking operation of the workpiece 2 by the end effector 1 from the state of FIG. FIG. 3A shows a first transition state of the end effector 1 after the actuator rod 55 is driven in the direction of arrow D from the state of FIG. When the actuator rod 55 is driven in the direction of arrow D, as described above, the link member 20 maintains the horizontal state and moves in the direction of arrow D. Then, since the center Cw of the work 2 is closer to the finger 31 than to the finger 30, the finger 31 comes into contact with the work 2 and the finger 31 cannot be closed any more. Thus, the finger 31 is in a non-moving state at the contact position with the workpiece 2, and the link rod 51 does not move any more (cannot move in the positive direction of the Z axis). On the other hand, since the finger 30 is not in contact with the work 2, the finger 30 can be further closed.

  FIG. 3B shows a second transition state of the end effector 1 after the actuator rod 55 is further driven in the direction of arrow D from the state of FIG. When the actuator rod 55 is further moved in the direction of the arrow D from the state of FIG. 3A, the link member 20 rotates and tilts with the connecting portion 20c with the link rod 51 as a fulcrum, so that the link rod 50 further moves along the Z axis. It can move in the positive direction. As a result, the finger 30 is further closed and does not move any more at the position where it is in contact with the workpiece 2. Thus, the workpiece 2 is held by the fingers 30 and 31.

  As described above, in the end effector 1 according to the first embodiment, when the fingers 30 and 31 are opened and closed by one actuator via the link member 20, the fingers 30 and 31 are driven other than the center of the link member 20. 31 can be opened and closed. Further, in the end effector 1, according to the position and posture of the work 2 with respect to the link member 20, after one finger abuts the work during the closing operation, only the other finger can perform the closing operation. It is comprised so that the operation | movement which closes unevenly can be performed. Thus, the end effector 1 can grip the workpiece 2 with the fingers 30 and 31 even if the center of the end effector 1 (center of the link member 20) and the center of the workpiece 2 are deviated.

Second Embodiment
FIG. 4 is a schematic cross-sectional view of the end effector 101 according to the second embodiment of the present invention. Constituent elements of the end effector 101 that are the same as the constituent elements of the end effector 1 according to the first embodiment are given the same reference numerals, and common descriptions are omitted. The end effector 101 includes a base portion 110, a link member 120, fingers 30 and 31, tension springs 40 and 41, link rods 50 and 51, an actuator rod 55, and an adsorption rod 160.

  In order to insert and arrange the suction rod 160 so that the axial direction of the suction rod 160 is parallel to the Z-axis direction, in addition to the hole portion through which the link rods 50 and 51 are inserted and arranged in the base portion 110. Through-holes 111 are formed. Similarly to the through hole 111, the link member 120 is also provided with a through hole 121 for inserting and arranging the suction rod 160. The through holes 111 and 121 are formed at substantially the center of the surface perpendicular to the Z axis in the base portion 110 and the link member 120, respectively.

  The suction rod 160 is held by a member (not shown). FIG. 4 shows a configuration in which the suction rod 160 is not in contact with the link member 120 and the base part 110. In this case, assuming that the holding member of the suction rod 160 and the holding member of the base portion 110 can be relatively moved in the longitudinal direction of the suction rod 260, the same operation as that of the end effector 301 according to a fifth embodiment to be described later. (See FIGS. 10 and 11). On the other hand, by adopting a structure in which the suction rod 160 is fixed to the base portion 110 in the through hole 111 formed in the base portion 110, the suction holding by the suction rod 160 and the gripping by the fingers 30, 31 can be executed simultaneously. It is good.

  The through hole 111 of the base part 110 is provided in the approximate center (middle) between the support parts 12 and 13 in the X-axis direction. Further, the through-hole 121 of the link member 120 is provided in the approximate center between the connection portions 120b and 120c between the link member 120 and the link rods 50 and 51 in the X-axis direction.

  Here, if it is assumed that the distance L1 and the distance L2 according to the definitions in the first embodiment are equal, the arrangement positions of the actuator rod 55 and the adsorption rod 160 overlap, so the adsorption rod 160 cannot be arranged. Disappear. On the other hand, similarly to the end effector 1 according to the first embodiment, since the end effector 101 is also “L1 ≠ L2”, the suction rod 160 is placed at the center between the fingers 30 and 31 in the X-axis direction. It is possible to arrange.

  The suction rod 160 is a rod-like member having a hollow shape and having a suction pad 170 attached to the tips on the fingers 30 and 31 side. By adjusting the inside of the suction rod 160 to a negative pressure through the upper opening 161 of the suction rod 160, the suction rod 160 sucks and holds a workpiece (not shown) by the suction pad 170. That is, the end effector 101 can hold the workpiece more reliably by using both the suction holding of the workpiece by the suction pad 170 and the mechanical gripping of the workpiece by the fingers 30 and 31 in combination.

<Third Embodiment>
The end effector according to the third embodiment is generally obtained by remodeling an end effector having two fingers into an end effector having three fingers.

  5A and 5B are cross-sectional views showing a first state and a second state of the end effector 201 according to the third embodiment, respectively. For convenience of explanation, as shown in FIGS. 5A and 5B, an X axis, a Y axis, and a Z axis that are orthogonal to each other are defined. The end effector 1 includes a support member 210, a link member 220, fingers 230, 231, 232, link rods 250, 251, 252 and an actuator rod 255. The first state in FIG. 5A is an open state in which the fingers 230 to 232 are opened, and the second state in FIG. 5B is a closed state in which the fingers 230 to 232 are closed.

  In the end effector 201, the fingers 230 to 232 are rotatably supported by the support member 210. Each of the fingers 230 to 232 is urged in the opening direction by an urging member (not shown) such as a torsion coil spring loaded in a support portion with the support member 210, for example. The rotational moment around the support portion of the finger 230 by the biasing force of the biasing member, that is, the link stiffness of the finger 230 is different from the link stiffness of each of the fingers 231 and 232. Such a difference in link rigidity can be realized by using urging members having different urging forces as described in the first embodiment.

  The fingers 230 to 232 are connected to the annular link member 220 via link rods 250 to 252, respectively. The connecting portion between the finger 230 and the link rod 250 is rotatable so that the finger 230 can be opened and closed when the link member 220 moves in the Z-axis direction. Further, the connecting portion between the link rod 250 and the link member 220 is rotatable so that the upper surface of the link member 220 can take a state inclined at a predetermined angle with respect to the XY plane. The same applies to the connection portion between the finger 231 and the link rod 251, the connection portion between the finger 232 and the link rod 252, and the connection portion between the link rods 251 and 252 and the link member 220.

  The actuator rod 255 is rotatably connected to the link member 220 and is driven in the Z-axis direction by an actuator (not shown). FIG. 6 is a top view of the end effector 201 and is a view for explaining the positional relationship of each connection portion between the link member 220, the actuator rod 255, and the link rods 250 to 252. FIG. A connecting portion between the link member 220 and the actuator rod 255 is denoted as “O”, and a connecting portion between the link member 220 and the link rods 250, 251, and 252 is denoted as “P”, “Q”, and “R”. If the distance between the connecting portions O and P is ‘L21’, and the distance between the connecting portions O and Q and the distance between the connecting portions O and R is ‘L22’, ‘L21 ≠ L22’. However, the link rigidity of the fingers 230 to 232 and the values of the distances L21 and L22 are set so that the moments around the connection portion O between the link member 220 and the actuator rod 255 are balanced in the X-axis direction and the Y-axis direction.

  Thereby, also in the end effector 201, it is possible to open and close the three fingers 230 to 232 with one actuator, similarly to the end effector 1 according to the first embodiment. At this time, when the workpiece is not gripped, the fingers 230 to 232 can be opened and closed evenly, and when one of the three fingers 230 to 232 comes into contact with the workpiece, the finger 230 to 232 is not suitable depending on the position and posture of the workpiece. It is possible to perform the closing operation evenly.

<Fourth embodiment>
FIG. 7 is a perspective view showing a schematic configuration of the end effector 202 according to the fourth embodiment. The end effector 202 has a structure in which a suction rod 260 having a suction pad 270 attached to the tip of the fingers 230 to 232 is provided to the end effector 201 according to the third embodiment. The suction rod 260 is the same as the suction rod 160, and a description thereof is omitted here. Through holes 221 and 211 through which the suction rod 260 is inserted are formed at substantially the center in the XY plane of the link member 220 and the support member 210, and the suction rod 260 has an axial direction substantially parallel to the Z axis. It is arranged to be. As with the end effector 101 according to the second embodiment, the end effector 202 is capable of holding a workpiece using both workpiece adsorption and mechanical gripping by the fingers 230 to 232. Since the usage mode of the end effector 202 is the same as the usage mode of the end effector 101, description thereof is omitted here. Moreover, the operation mode of the fingers 230 to 232 in the end effector 202 is the same as the operation mode of the fingers 230 to 232 in the end effector 201 according to the third embodiment, and a description thereof will be omitted.

<Fifth Embodiment>
FIG. 8 is a schematic cross-sectional view of an end effector 301 according to the fifth embodiment. For convenience of explanation, as shown in FIGS. 5A and 5B, an X axis, a Y axis, and a Z axis that are orthogonal to each other are defined.

  The end effector 301 includes a suction unit 310 and a gripping unit 320. The suction unit 310 includes a base 311, a suction rod 312, a suction pad 313, a rail 314, and a rack 315. The gripping unit 320 includes a finger base 321, a slide block 322, a pinion 323, a lift motor 324, and fingers 325A and 325B. The gripping unit 320 includes finger rods 326A and 326B, finger opening and closing links 327A and 327B, and finger opening and closing motors 328A and 328B. The end effector 301 is attached to end effector moving means such as a robot arm (not shown) via the base portion 311.

  In the suction unit 310, the suction rod 312 is hollow, and a suction pad 313 is attached to the lower end thereof. A negative pressure is supplied to the inside of the suction rod 312 from an opening (not shown) provided in the suction rod 312, so that the work can be sucked and held by the suction pad 313. A rail 314 that supports the gripping unit 320 and a rack 315 for moving the gripping unit 320 in the Z-axis direction are attached to the suction rod 312 along the longitudinal direction (Z-axis direction). Details of the supporting method and moving method of the gripping unit 320 will be described later.

  In the gripping unit 320, a slide block 322, an elevating motor 324, and finger opening / closing motors 328 </ b> A and 328 </ b> B are fixed to the finger base 321. The fingers 325A and 325B are supported by the finger base 321 so as to be rotatable in the directions of arrows G and H, respectively. The slide block 322 is fitted to the rail 314 so as to be movable in the Z-axis direction, and the rail 314 and the slide block 322 function as a guide (guide means) for moving the gripping unit 320 in the Z-axis direction. . Thus, the gripping unit 320 is supported by the suction rod 312 so as to be movable in the Z-axis direction.

  The pinion 323 attached to the drive shaft of the lifting / lowering motor 324 meshes with the rack 315, and the gripping unit 320 can be moved in the Z-axis direction by driving the lifting / lowering motor 324. Finger rod 326A is rotatably connected to finger 325A and finger opening / closing link 327A, and finger opening / closing link 327A is connected to a drive shaft of finger opening / closing motor 328A. Thus, as will be described later, the finger 325A can be opened and closed in conjunction with the drive (rotation) of the finger opening / closing motor 328A (see FIG. 9B). The relationship between the finger 325B, the finger rod 326B, the finger opening / closing link 327B, and the finger opening / closing motor 328B is the same as the relationship between the finger 325A, the finger rod 326A, the finger opening / closing link 327A, and the finger opening / closing motor 328A. Therefore, the finger 325B can be opened and closed in conjunction with the driving (rotation) of the finger opening / closing motor 328B.

  When the end effector 301 is in the state shown in FIG. 8, that is, when the gripping unit 320 is located near the end in the positive direction of the Z axis, it is defined that “the gripping unit 320 is in the retracted position”. To do.

  FIG. 9 is a diagram for explaining the operation of the end effector 301. FIG. 9A is a cross-sectional view showing a state in which the lifting motor 324 is driven and the gripping unit 320 is moved from the retracted position shown in FIG. 8 to the suction pad 313 side (Z-axis negative direction side). When the end effector 301 is in the state shown in FIG. 9A, that is, when the gripping unit 320 is located near the end in the negative Z-axis direction, “the gripping unit 320 is in the gripping position”. Define. The fingers 325A and 325B are in an open state in which the workpiece (not shown) is not gripped in the state of FIGS. 8 and 9A.

  FIG. 9B is a cross-sectional view for explaining a gripping operation of a workpiece (not shown) by the gripping unit 320. As shown in FIG. 9B, the finger opening / closing motor 328A is driven so that the finger opening / closing link 327A rotates counterclockwise. As a result, the finger rod 326A moves in the positive Z-axis direction and the negative X-axis direction, and the finger 325A rotates in the counterclockwise direction and contacts a workpiece (not shown). Similarly, the finger opening / closing motor 328B is driven so that the finger opening / closing link 327B rotates in the clockwise direction. As a result, the finger rod 326B moves in the positive Z-axis direction and in the positive X-axis direction, and accordingly, the finger 325B rotates clockwise and comes into contact with a workpiece (not shown). Thus, the fingers 325A and 325B are in a closed state and grip a workpiece (not shown).

  In a state where the fingers 325A, 325B are gripping the workpiece (closed state), the end effector moving means is driven to move the workpiece to a predetermined position, and then the fingers 325A, 325B are opened so that the fingers 325A, 325B are opened. 328A and 328B are driven. As a result, the workpiece is released from the fingers 325A and 325B, and the conveyance of the workpiece is completed.

  10 and 11 are diagrams for explaining an example of a workpiece picking operation by the end effector 301. FIG. Here, it is assumed that the workpiece 2 is in the corner of the box 3. In this case, the gripping unit 320 cannot be inserted into the box 3. Therefore, as shown in FIG. 10, the fingers 325A and 325B are in the open state, and the gripping unit 320 is in the retracted position. Then, the suction rod 312 is inserted into the box 3 so that the gripping unit 320 does not interfere with the box 3 by a moving means (such as a robot hand (not shown)) of the end effector 301, and the suction pad 313 is inserted into the work 2 for example. It is arranged in the center of the upper surface. Subsequently, the work 2 is sucked and held on the suction pad 313.

  It should be noted that the suction holding position of the work 2 by the suction pad 313 is preferably a position corresponding to the center of gravity of the work 2 on the upper surface of the work 2. However, if the workpiece 2 can be lifted without dropping when the suction rod 312 is raised and can be gripped by the fingers 325A and 325B as will be described later, the suction position with respect to the workpiece 2 is limited. Not.

  Thereafter, as shown in FIG. 11A, the entire end effector 301 is moved in the positive direction of the Z axis, and the lifting motor 324 is driven to move the gripping unit 320 from the retracted position to the gripping position. In other words, the gripping unit 320 is lowered in the Z-axis negative direction while pulling out the suction rod 312 and the work 2 from the box 3 while the work 2 is sucked and held by the suction pad 313. At that time, the speed at which the gripping unit 320 moves from the retracted position to the gripping position is set to be equal to or less than the moving speed of the end effector 301 in the positive Z-axis direction, so that interference between the gripping unit 320 and the box 3 can be prevented. As will be described later with reference to FIG. 11B, if the workpiece 2 can be gripped again by gripping with the fingers 325A and 325B, the workpiece 2 tilts when the workpiece 2 held by suction is lifted. You may be in the state.

  Finally, as shown in FIG. 11B, by moving the fingers 325A and 325B from the open state to the closed state, the workpiece 2 is sucked and held by the suction pad 313 and is held by the fingers 325A and 325B. State. Thereby, the end effector 301 can hold | maintain the workpiece | work 2 more firmly, and when the end effector 301 is moved in order to convey the workpiece | work 2 to a predetermined position, it prevents that the workpiece | work 2 falls. be able to. In addition, it is also possible to place the gripped work 2 on a place where the gripping unit 320 cannot enter by a procedure reverse to the above-described procedure.

  As described above, the end effector 301 according to the present embodiment has the same effects as the end effector 101 according to the second embodiment described above. Further, according to the end effector 301, the workpiece 2 is picked flexibly and reliably in accordance with the environment in which the workpiece 2 is housed in the box 3 or the position of the workpiece 2 in the box 3. It becomes possible.

<Sixth Embodiment>
FIG. 12 is a perspective view of an end effector 401 according to the sixth embodiment. 5th Embodiment demonstrated the end effector 301 provided with the two fingers 325A and 325B which do not have a joint in a finger intermediate part. On the other hand, the end effector 401 includes a gripping unit 420 having three fingers 425A, 425B, and 425C having joints at an intermediate portion, and the other configuration is the same as the end effector 301. In FIG. 12, constituent elements of the end effector 401 that are the same as the constituent elements of the end effector 301 are given the same reference numerals, and descriptions thereof are omitted here.

  The gripping unit 420 is movable along the Z-axis direction shown in FIG. In addition, the fingers 425A to 425C can perform an opening / closing operation on the finger base 321 and an opening / closing operation at a joint portion. In this way, the size, shape and weight range of the work that can be gripped is widened, and it is possible to cope with picking up and transporting various kinds of work.

  Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. Furthermore, each embodiment mentioned above shows only one embodiment of this invention, and it is also possible to combine each embodiment suitably. For example, as long as there is no specific description, the present invention is not limited to the functions, materials, shapes, numbers and relative arrangements of the components and members shown in the above embodiments. Moreover, although the said embodiment demonstrated the end effector provided with 2 or 3 fingers, the number of fingers should just be more than one and is not limited to 2 or 3.

DESCRIPTION OF SYMBOLS 1,101 End effector 10 Base part 12,13 Support part 20 Link member 30,31 Finger 40,41 Extension spring 50,51 Link rod 55 Actuator rod 111,121 Through-hole 120 Link member 160 Adsorption rod 310 Adsorption unit 315 Rack 320 Grip unit 323 Pinion 324 Lifting motor

Claims (10)

A plurality of fingers for gripping the workpiece;
A link member coupled to the plurality of fingers;
Drive means for driving the link member;
An end effector comprising biasing means for biasing each of the plurality of fingers in a predetermined direction,
At least two fingers of the plurality of fingers have different link rigidity,
An end effector characterized in that a distance from a connecting portion between the link member and the driving means to each connecting portion between the link member and the at least two fingers takes different values.   The end effector according to claim 1, wherein a sum of moments around a connection portion between the link member and the driving unit is zero.   The end effector according to claim 1 or 2, wherein a suction rod for sucking and holding the workpiece is disposed so as to penetrate the link member in a direction substantially parallel to a drive direction of the drive means. A support member for supporting the plurality of fingers;
The end effector according to claim 3, wherein the suction rod penetrates the support member.   The end effector according to claim 4, wherein the support member, the link member, and the suction rod are capable of relative movement in a longitudinal direction of the suction rod. A gripping unit for gripping the workpiece;
A suction unit that holds and holds the workpiece;
A moving means for moving the position of the gripping unit relative to the suction unit, and an end effector comprising:
The gripping unit is
A support member;
A plurality of fingers supported by the support member;
Drive means for causing the plurality of fingers to transition between a closed state for gripping a workpiece and an open state for releasing the gripped workpiece;
The adsorption unit is
Having a suction rod arranged to penetrate substantially the center of the support member;
The end effector characterized in that the moving means moves the gripping unit in the longitudinal direction of the suction rod.   The gripping unit is capable of gripping the work held by the suction rod with the plurality of fingers at a retracted position where the suction rod does not contact the work when the suction rod sucks and holds the work. The end effector according to claim 6, wherein the end effector is movable between positions.   The end effector according to claim 6 or 7, wherein in the longitudinal direction of the suction rod, the thickness of the gripping unit when the plurality of fingers are in the open state is shorter than the length of the suction rod. The moving means is
A rack disposed on the suction rod along the longitudinal direction of the suction rod;
A pinion disposed on the gripping unit and meshing with the rack;
Guiding means for guiding the gripping unit in the longitudinal direction of the suction rod;
A motor for rotating the pinion,
The end effector according to claim 6, wherein the pinion and the motor are arranged on the support member. The end effector according to any one of claims 1 to 9,
And an end effector moving means for holding the end effector.

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