Hand

Abstract

The invention provides a hand. The hand (2) is provided with a hand body (20), a first finger (3) provided to the hand body (20), a second finger (5) provided to the hand body (20), and an advancing and retreating actuator (4) that advances and retreats the first finger (3) independently from the second finger (5) in a prescribed direction (Z) with respect to the hand body. The first finger (3) has a belt (35) that forms a contact surface (35a) with the article and moves in an in-plane direction of the contact surface (35a).

Description

Technical Field

[0001] The present invention relates to hands. Background Art

[0002] Until now, a hand including fingers having belts provided on the contact surfaces with an object has been known. For example, the hand described in Patent Document 1 includes a plurality of fingers. In each finger, a belt is provided on the contact surface with an object. When the belt is driven in a state where the object contacts the belt, the object moves together with the belt. In this way, the object is pulled in the moving direction of the belt.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2016-30316 Summary of the invention

[0004] However, the hand including the fingers provided with the above-mentioned belt can be used not only for simply holding an object, but also for pulling in an object, etc. However, there are many possibilities for utilizing such a hand. In other words, by improving the structure of the hand, it is possible to further improve the convenience of the hand.

[0005] In view of the above, an object of the present invention is to improve the convenience of a hand including fingers provided with a band.

[0006] The hand of the present invention includes a hand body, a first finger, a second finger and an advance and retreat actuator, wherein the first finger is arranged on the hand body, the second finger is arranged on the hand body, the advance and retreat actuator enables the first finger to advance and retreat independently from the second finger in a specified first direction relative to the hand body, and the first finger has a belt, which forms a contact surface with an object and moves in the in-plane direction of the contact surface.

[0007] (Effects of the Invention)

[0008] According to the hand of the present invention, the convenience of the finger provided with the band can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram showing the structure of a robot system.

[0010] Figure 2 This is the front view of the hand.

[0011] Figure 3 It is a three-dimensional picture of the hand.

[0012] Figure 4 This is a bottom view of the hand.

[0013] Figure 5 yes Figure 4 Cross-sectional view of the hand at line VV.

[0014] Figure 6 yes Figure 4 Cross-sectional view of the hand at line VI-VI.

[0015] Figure 7 yes Figure 2 Cross-sectional view of the hand at line VII-VII.

[0016] Figure 8 yes Figure 2 Partial cross-sectional view of the hand at line VIII-VIII.

[0017] Fig. 9 yes Figure 4 Cross-sectional view of the hand at line IX-IX.

[0018] Fig.10 The hand is in a completely closed state, equivalent to Figure 5 sectional view of .

[0019] Fig.11 It is the hand when the restraint switches from the restrained state to the released state, equivalent to Figure 6 sectional view of .

[0020] Fig.12 : is a block diagram showing a schematic hardware structure of the control device.

[0021] Fig.13 It is used to explain the hand's forward and backward movements, equivalent to Figure 6 sectional view of .

[0022] Fig.14 It is a schematic front view of the hand for explaining the action when the forward and backward action is completed.

[0023] Fig.15 It is a schematic front view of a hand for explaining a holding action.

[0024] Fig.16 This is a hand for explaining the operation of the buffer 8, equivalent to Figure 5 sectional view of .

[0025] Fig.17 This is an explanatory diagram for explaining the state of the hands at the beginning of pulling and grasping.

[0026] Fig.18 This is an explanatory diagram for explaining a hand in the middle of pulling in and grasping.

[0027] Fig.19 This is an explanatory diagram of the hand for explaining the state when the pulling-in grip is completed.

[0028] Fig. 20 This is an explanatory diagram for explaining an example of pulling in an article W by hand.

[0029] Fig.21 This is an explanatory diagram for explaining another example of pulling in an article W by hand. DETAILED DESCRIPTION

[0030] Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

[0031] Figure 1 is a schematic diagram showing the structure of the robot system 100 .

[0032] The robot system 100 includes a robot 110 including a robot arm 1 and a hand 2 , and a control device 120 for controlling the robot 110 .

[0033] The robot 110 is, for example, an industrial robot. The robot 110 moves a hand 2 by a robot arm 1. The hand 2 is connected to the robot arm 1, and more specifically, is connected to the front end of the robot arm 1. The hand 2 is one of the so-called end effectors. The hand 2 performs various processes such as holding an object.

[0034] The robot arm 1 includes a plurality of links 11 and a plurality of joints 12. Each joint 12 rotatably connects two adjacent links 11. Each joint 12 is rotationally driven by an electric motor. The electric motor is, for example, a servo motor. An encoder for detecting the rotation angle of the electric motor is provided in the electric motor.

[0035] 〔hand〕

[0036] Figure 2 It is the front view of hand 2. Figure 3 It is a stereogram of hand 2. Figure 4 : is a bottom view of the hand 2. The hand 2 includes a hand body 20, a first finger 3, and a second finger 5. The first finger 3 is provided on the hand body 20, and the second finger 5 is provided on the hand body 20. The first finger 3 is provided on the hand body 20 so as to be able to move forward and backward in a predetermined first direction Z. The first finger 3 has a belt 35, and the belt 35 forms a contact surface 35a with an object and moves in the in-plane direction of the contact surface 35a.

[0037] The first finger 3 and the second finger 5 perform an opening and closing action in a specified second direction X. In this example, the first finger 3 is arranged on the hand body 20 so as not to be movable in the second direction X. The second finger 5 is arranged on the hand body 20 so as to be movable relative to the first finger 3 in the second direction X. In other words, the first finger 3 moves forward and backward in the first direction Z, but cannot move in the second direction X. The second finger 5 moves in the second direction X, but cannot move in the first direction Z. It should be noted that the second direction X is a direction intersecting the first direction Z, and more specifically, a direction substantially orthogonal to the first direction Z.

[0038] Figure 5 yes Figure 4 The hand 2 further includes an advance and retreat actuator 4, which drives the first finger 3. The advance and retreat actuator 4 enables the first finger 3 to advance and retreat in the first direction Z relative to the hand body 20 independently from the second finger 5.

[0039] The hand 2 may also include an opening and closing actuator 6, which drives the second finger 5. The opening and closing actuator 6 moves the second finger 5 in the second direction X relative to the hand body 20. The second finger 5 moves in the second direction X in a direction close to the first finger 1, so that the first finger 3 and the second finger 5 are closed. On the other hand, the second finger 5 moves in the second direction X in a direction away from the first finger 3, so that the first finger 3 and the second finger 5 are opened.

[0040] The hand 2 can perform a holding action and a moving action. The holding action is an action of holding an object by the first finger 3 and the second finger 5. In the holding action, the hand 2 holds the object by the first finger 3 and the second finger 5 by moving the second finger 5 in the second direction X. The moving action is an action of moving the object by the belt 35 of the first finger 3. In the moving action, the hand 2 moves the object in the in-plane direction of the contact surface 35a by moving the belt 35 while the contact surface 35a of the belt 35 of the first finger 3 is in contact with the object. At this time, the hand 2 may also move the first finger 3 in the first direction Z in advance so that the first finger 3 protrudes more than the second finger 5 in the first direction Z. In this way, the first finger 3 can approach the object more easily.

[0041] Figure 6 yes Figure 4 The hand 2 may also include a restraint 7, which switches between a restraint state in which the first finger 3 cannot be moved in the first direction Z and a release state in which the first finger 3 can be moved in the first direction Z. When the hand 2 moves the first finger 3 in the first direction Z, the restraint 7 is in the release state. On the other hand, when the hand 2 performs a holding action or a moving action, the restraint 7 is in the restraint state.

[0042] The hand 2 may also include a buffer 8, which elastically supports the first finger 3 so that the first finger 3 can move relative to the hand body 20 in the first direction Z. When the hand 2 performs a holding action or a moving action, it sometimes moves in the first direction Z to approach an object or the like. Therefore, the first finger 3 may contact other objects from the first direction Z. At that time, the buffer 8 can absorb the impact acting on the first finger 3, and the first finger 3 moves in the first direction Z.

[0043] Hereinafter, the structure of the hand 2 will be described in detail. For convenience of description, a direction orthogonal to both the first direction Z and the second direction X is referred to as a third direction Y.

[0044] [Hand body]

[0045] like Figure 2 As shown in FIG. 1 and FIG. 2 , the hand body 20 is formed in a box shape. The hand body 20 supports the first finger 3 and the second finger 5. The hand body 20 accommodates the advance / retract actuator 4, the opening / closing actuator 6, the restrainer 7, and the buffer 8.

[0046] 〔First Finger〕

[0047] like Figure 2 as well as Figure 3 As shown, the first finger 3 has a finger body 30 and a band 35. The finger body 30 extends from the hand body 20 in a substantially first direction Z. The finger body 30 is formed to be gradually tapered toward the front end of the first direction Z. In detail, the dimension of the finger body 30 in the second direction X becomes smaller as it approaches the front end of the finger body 30.

[0048] Hereinafter, for the sake of convenience, the front end of the first finger 3 or the finger body 30 means the front end in the first direction Z. In addition, the second direction X is also referred to as the “opening and closing direction X”. The inside of the opening and closing direction X means the inside of the first finger 3 and the second finger 5 in the opening and closing direction X. The outside of the opening and closing direction X means the outside of the first finger 3 and the second finger 5 in the opening and closing direction X.

[0049] like Figure 5 As shown, the finger body 30 accommodates a first synchronous pulley 31 and a second synchronous pulley 32. The axis of the first synchronous pulley 31 and the axis of the second synchronous pulley 32 extend in the third direction Y. The finger body 30 rotatably supports the first synchronous pulley 31 and the second synchronous pulley 32 around the axis of each of the first synchronous pulley 31 and the second synchronous pulley 32. The first synchronous pulley 31 and the second synchronous pulley 32 are arranged substantially in the first direction Z. The second synchronous pulley 32 is arranged at the front end of the finger body 30. The first synchronous pulley 31 is arranged closer to the hand body 20 than the second synchronous pulley 32.

[0050] The belt 35 is an endless belt. Furthermore, the belt 35 is a toothed belt, which is a so-called synchronous belt. The belt 35 is wound around the first synchronous pulley 31 and the second synchronous pulley 32. Figure 3As shown, the belt 35 is exposed to the outside from the finger body 30 except for a portion wound around the first timing pulley 31. The belt 35 includes a portion extending between the first timing pulley 31 and the second timing pulley 32 on the inner side in the opening and closing direction X and a portion extending between the first timing pulley 31 and the second timing pulley 32 on the outer side in the opening and closing direction X. The portion extending between the first timing pulley 31 and the second timing pulley 32 on the inner side in the opening and closing direction X forms a contact surface 35a. The contact surface 35a is a substantially flat surface facing the second finger 5 side in the opening and closing direction X.

[0051] like Figure 5 As shown, the finger body 30 has a plurality of rollers 34. The axis of each roller 34 extends in the third direction Y. The finger body 30 rotatably supports the plurality of rollers 34 around the axis of each roller 34. The plurality of rollers 34 are arranged along the first direction Z inside the belt 35, more specifically, along the contact surface 35a. The portion of the belt 35 that forms the contact surface 35a is maintained in a planar shape by contacting the plurality of rollers 34.

[0052] 〔Advance and Retraction Actuator〕

[0053] like Figure 5 as well as Figure 6 As shown, the advance and retreat actuator 4 is installed on the finger body 30. The advance and retreat actuator 4 drives the belt 35 so that the belt 35 moves in the in-plane direction of the contact surface 35a. The advance and retreat actuator 4 has a reducer 41, an electric motor 42, a transmission mechanism 43 and a position acquisition sensor 44. For example, the electric motor 42 is a servo motor. The electric motor 42 is arranged with the first finger 3 in the first direction Z, and is configured in a manner that the rotation axis M of the electric motor 42 extends in the first direction Z. The position acquisition sensor 44 is provided on the electric motor 42 to detect the rotation position of the electric motor 42. The position acquisition sensor 44 is, for example, an encoder or a Hall element sensor. The reducer 41 is connected to the electric motor 42. The reducer 41 has an output shaft 41a, which reduces the rotation of the electric motor 42 and outputs it via the output shaft 41a. It should be noted that when the electric motor 42 is a stepping motor, the position acquisition sensor 44 can be omitted. The storage portion 33 is formed at the end of the finger body 30 on the opposite side of the front end in the first direction Z. The electric motor 42 is accommodated in the accommodation portion 33 and fixed to the finger body 30. Since the electric motor 42 is arranged to be aligned with the first finger 3 in the first direction Z with the rotation axis M extending in the first direction Z, the first finger 3 can be made thinner.

[0054] Figure 7 yes Figure 2 A cross-sectional view of hand 2 at line VII-VII of FIG. Figure 7As shown, the transmission mechanism 43 has a first gear 43a, a second gear 43b, a third gear 43c, a fourth gear 43d and a rotating shaft 43e. The axis of the rotating shaft 43e extends to the third direction Y. The finger body 30 rotatably supports the rotating shaft 43e with the axis of the rotating shaft 43e as the center. The axis of the rotating shaft 43e is substantially orthogonal to the axis of the output shaft 41a of the reducer 41. The first gear 43a is non-rotatably mounted on the output shaft 41a. The second gear 43b and the third gear 43c are non-rotatably mounted on the rotating shaft 43e. The fourth gear 43d is non-rotatably mounted on the rotating shaft 31a of the first synchronous pulley 31. The first gear 43a and the second gear 43b are bevel gears that mesh with each other. The third gear 43c and the fourth gear 43d are spur gears that mesh with each other. The first gear 43a, the second gear 43b, the third gear 43c and the fourth gear 43d form a gear train. When the electric motor 42 is working, the rotation of the output shaft 41a is sequentially transmitted to the first gear 43a, the second gear 43b, the third gear 43c and the fourth gear 43d, and the first synchronous pulley 31 rotates. When the first synchronous pulley 31 rotates, the belt 35 wound around the first synchronous pulley 31 moves. The portion of the belt 35 that forms the contact surface 35a moves in the first direction Z. At this time, the second synchronous pulley 32 rotates as the belt 35 rotates.

[0055] 〔buffer〕

[0056] The buffer 8 is supported by the hand body 20 so as to be movable in the first direction Z. The buffer 8 is elastically supported by the first finger 3 so as to be movable in the first direction Z. Figure 7 As shown, the buffer 8 includes a holder 81 that supports the first finger 3, a linear guide 82 that guides the first finger 3 in the first direction Z, and a third spring 83 that elastically absorbs the movement of the first finger 3 in the first direction Z. The third spring 83 is an example of a third elastic member.

[0057] The retainer 81 has a side wall 84 and a cover 85. The side wall 84 extends in a plane that is substantially parallel to both the first direction Z and the second direction X, that is, in a ZX plane. The cover 85 is formed in a cylindrical shape that is open at the bottom. The cover 85 is arranged so as to surround the outer periphery of the reducer 41, the electric motor 42, and the position acquisition sensor 44. The cover 85 does not contact the reducer 41, the electric motor 42, and the position acquisition sensor 44. More specifically, although Figure 7 Although it is difficult to see in the figure, a slight gap is provided between the upper part of the cover 85 and the electric motor 42 and the position acquisition sensor 44. A larger gap than the upper part of the cover 85 is provided between the lower part of the cover 85 and the speed reducer 41 and the electric motor 42. The upper end portion of the side wall 84 and the upper end portion of the cover 85 are connected to each other.

[0058] The linear guide 82 connects the holder 81 and the first finger 3. The linear guide 82 linearly guides the first finger 3 in the first direction Z. That is, the holder 81 supports the first finger 3 movably in the first direction Z via the linear guide 82. The movement of the first finger 3 is restricted by the stoppers at both ends in the first direction Z. Figure 8 yes Figure 2 A partial cross-sectional view of the hand 2 at the VIII-VIII line. Figure 8 As shown, the buffer 8 has two linear guides 82. Each linear guide 82 has a first rail 82a, a second rail 82b, and a plurality of balls or a plurality of rollers disposed between the first rail 82a and the second rail 82b. The first rail 82a and the second rail 82b are relatively movable in the first direction Z. The first rail 82a is mounted on the side wall 84 of the holder 81, and the second rail 82b is mounted on the finger body 30. In detail, the storage portion 33 of the finger body 30 has a side wall 36 extending substantially parallel to the side wall 84. The second rail 82b is mounted on the side wall 36.

[0059] The third spring 83 is, for example, a coil spring. The third spring 83 is arranged between the retainer 81 and the finger body 30 in a compressed state. Figure 7 As shown, the third spring 83 is disposed between the cover 85 of the holder 81 and the storage portion 33 of the finger body 30. The third spring 83 is disposed so as to surround the outer circumference of the electric motor 42. The third spring 83 exerts an elastic force to separate the holder 81 and the finger body 30 from each other in the first direction Z. That is, the first finger 3 is urged in the direction away from the holder 81 in the first direction Z by the third spring 83.

[0060] The first finger 3 is usually located at a position farthest away from the holder 81 in the first direction Z due to the elastic force of the third spring 83. When an impact is applied to the front end of the first finger 3 toward the hand body 20 in the first direction Z, the first finger 3 moves in the direction close to the holder 81 in the first direction Z against the elastic force of the third spring 83. The movement of the first finger 3 is absorbed by the third spring 83. As a result, the buffer 8 can absorb the impact applied to the first finger 3, and the first finger 3 moves in the first direction Z. Here, since the third spring 83 is arranged in a manner surrounding the outer periphery of the electric motor 42, the buffer 8 can be formed compactly.

[0061] The buffer 8 supporting the first finger 3 is supported by the hand body 20 so as to be movable in the first direction Z. Figure 8 As shown, the hand body 20 has a linear guide 21, and the linear guide 21 guides the buffer 81 to the first direction Z.

[0062] The linear guide 21 connects the hand body 20 and the buffer 8. That is, the hand body 20 supports the buffer 8 so as to be movable in the first direction Z via the linear guide 21. The hand body 20 has two linear guides 21. Each linear guide 21 has a first rail 21a, a second rail 21b, and a plurality of balls or rollers arranged between the first rail 21a and the second rail 21b. The first rail 21a and the second rail 21b are configured to be relatively movable in the first direction Z. The first rail 21a is mounted on the hand body 20, and the second rail 21b is mounted on the buffer 8. In detail, the first rail 21a is mounted on a side wall of the hand body 20, namely the first side wall 20a. The second rail 21b is mounted on the retainer 81 of the buffer 8, more specifically, on the cover 85.

[0063] In this way, the first finger 3 is supported by the hand body 20 via the buffer 8 so as to be movable in the first direction Z. When the first finger 3 moves in the first direction Z, the advance / retract actuator 4 mounted on the finger body 30 also moves integrally with the first finger 3 in the first direction Z. That is, even when the first finger 3 moves in the first direction Z, the advance / retract actuator 4 can drive the belt 35.

[0064] 〔Second finger〕

[0065] like Figure 2 , Figure 3 as well as Figure 5 As shown in FIGS. 1 and 1 , the second finger 5 includes a finger body 50 , a fingertip 54 , a linear guide 55 that guides the fingertip 54 in the first direction Z, and a spring 56 that elastically absorbs movement of the fingertip 54 in the first direction Z.

[0066] The finger body 50 as a whole extends from the hand body 20 in a substantially first direction Z. Figure 2 As shown, the hand body 20 has a bottom wall 22. A guide hole 23 extending in a first direction Z is formed through the bottom wall 22. The finger body 50 passes through the bottom wall 22 through the guide hole 23. Figure 5 As shown, the first end 51 of the finger body 50 in the first direction Z is arranged inside the hand body 20. The finger body 50 protrudes downward from the hand body 20 in the first direction Z. A support wall 52 is formed in the portion of the finger body 50 exposed downward from the hand body 20. The support wall 52 extends in a plane that is substantially parallel to both the first direction Z and the third direction Y, that is, in the YZ plane.

[0067] The fingertip 54 is formed as a whole in a flat plate shape that is roughly parallel to the support wall 52. That is, the fingertip 54 extends in the first direction Z. A contact surface 54a that contacts an object is formed in the portion of the fingertip 54 that faces the first finger 3. The contact surface 54a is a plane that is roughly parallel to the contact surface 35a of the first finger 3. A pin 54b is provided at the end of the fingertip 54 on the side close to the hand body 20 in the first direction Z. The pin 54b extends toward the hand body 20 side, that is, upward in the first direction Z. A hole 50a that opens downward is formed in the portion of the finger body 50 that faces the pin 54b.

[0068] The linear guide 55 connects the finger body 50 and the fingertip 54. The linear guide 55 linearly guides the fingertip 54 in the first direction Z. That is, the finger body 50 supports the fingertip 54 so that it can move in the first direction Z via the linear guide 55. Figure 3 As shown, the second finger 5 has two linear guides 55 .

[0069] The spring 56 is, for example, a coil spring. Figure 3 as well as Figure 5 As shown in FIG. 1 , the spring 56 is disposed so as to surround the outer circumference of the pin 54b. The spring 56 is disposed between the finger body 50 and the fingertip 54 in a compressed state. The spring 56 exerts an elastic force to separate the finger body 50 and the fingertip 54 from each other in the first direction Z. That is, the fingertip 54 is urged in a direction away from the finger body 50 in the first direction Z by the spring 56. The movement amount of the fingertip 54 in the first direction Z is limited by the stopper.

[0070] The finger tip 54 is usually located at a position farthest away from the finger body 50 in the first direction Z due to the elastic force of the spring 56. When an impact is applied to the front end of the finger tip 54 toward the hand body 20 in the first direction Z, the finger tip 54 moves in the first direction Z toward the finger body 50 against the elastic force of the spring 56. At this time, the pin 54b enters the hole 50a of the finger body 50 without interfering with the finger body 50. The movement of the finger tip 54 is absorbed by the spring 56. As a result, the spring 56 can absorb the impact acting on the finger tip 54, and the second finger 5 moves in the first direction Z.

[0071] 〔Opening and closing actuator〕

[0072] Fig. 9 yes Figure 4 A cross-sectional view of hand 2 at line IX-IX. Figure 5 , Figure 6 as well as Fig. 9As shown, the opening and closing actuator 6 further includes a moving body 61, and the moving body 61 moves in conjunction with the second finger 5. In detail, the opening and closing actuator 6 further includes an electric motor 62, and the electric motor 62 moves the moving body 61, and the second spring 63 elastically connects the moving body 61 and the second finger 5. The opening and closing actuator 6 moves the second finger 5 in the opening and closing direction X by moving the moving body 61 by the electric motor 62. The opening and closing actuator 6 further includes a speed reducer 64a, a position acquisition sensor 64b, a feed screw 65, and a transmission mechanism 66. The electric motor 62 is an example of a driving source, and the second spring 63 is an example of a second elastic member.

[0073] like Figure 5 As shown, the feed screw 65 has a nut 67 and a threaded shaft 68 screwed with the nut 67. The nut 67 is integrally mounted on the moving body 61. The electric motor 62 drives the threaded shaft 68 to rotate, so that the moving body 61 moves in the axial direction of the threaded shaft 68 together with the nut 67. The moving body 61 moves in the axial direction of the threaded shaft 68, so that the second finger 5 connected to the moving body 61 via the second spring 63 moves in the opening and closing direction X.

[0074] In detail, the axis of the threaded shaft 68 extends in the opening and closing direction X. That is, the axis direction of the threaded shaft 68 coincides with the opening and closing direction X. The hand body 20 rotatably supports the threaded shaft 68 around the axis of the threaded shaft 68. The first end 51 of the finger body 50 has a first side wall 51b and a second side wall 51c arranged in the second direction X. The second side wall 51c is arranged on the inner side in the opening and closing direction X compared to the first side wall 51b, that is, arranged close to the first finger 3. The threaded shaft 68 penetrates the first end 51, specifically, the first side wall 51b and the second side wall 51c.

[0075] The nut 67 is fixedly mounted on the inner side of the moving body 61. The moving body 61 and the nut 67 are housed in the first end portion 51 of the finger body 50. Specifically, the moving body 61 and the nut 67 are disposed between the first side wall 51b and the second side wall 51c. The moving body 61 is prevented from rotating around the axis of the threaded shaft 68 by the first end portion 51. The moving body 61 has an arm 61a that protrudes outward from the first end portion 51.

[0076] The second spring 63 is accommodated in the first end portion 51. The second spring 63 is arranged between the moving body 61 and the second side wall 51c in a compressed state. In this way, the second spring 63 presses the moving body 61 toward the first side wall 51b. In other words, the second spring 63 presses the second finger 5 toward the inner side of the opening and closing direction X relative to the moving body 61.

[0077] The electric motor 62 is, for example, a servo motor. Fig. 9As shown, the electric motor 62 is configured in such a manner that the output shaft 62a extends in the opening and closing direction X. The position acquisition sensor 64b is provided on the electric motor 62 to detect the rotational position of the electric motor 62. The position acquisition sensor 64b is, for example, an encoder or a Hall element sensor. It should be noted that when the electric motor 62 is a stepping motor, the position acquisition sensor 64b can be omitted. The reducer 64a, the electric motor 62, and the position acquisition sensor 64b are housed in the hand body 20 and fixed to the hand body 20.

[0078] The transmission mechanism 66 includes a first synchronous pulley 66a, a second synchronous pulley 66b, and a synchronous belt 66c. The first synchronous pulley 66a is non-rotatably mounted on the output shaft 62a. The second synchronous pulley 66b is non-rotatably mounted on the threaded shaft 68. The first synchronous pulley 66a and the second synchronous pulley 66b are arranged at approximately the same position in the opening and closing direction X. The synchronous belt 66c is wound around the first synchronous pulley 66a and the second synchronous pulley 66b. When the electric motor 62 is working, the first synchronous pulley 66a rotates together with the output shaft 62a. When the first synchronous pulley 66a rotates, the second synchronous pulley 66b rotates via the synchronous belt 66c, and the threaded shaft 68 rotates together with the second synchronous pulley 66b. In this way, the driving force of the electric motor 62 is transmitted to the feed screw 65 via the transmission mechanism 66.

[0079] The opening and closing actuator 6 moves the second finger 5 in the opening and closing direction X and opens and closes by operating the electric motor 62. At this time, the moving body 61 moves in conjunction with the second finger 5. Specifically, the rotational driving force of the electric motor 62 is transmitted to the threaded shaft 68 via the transmission mechanism 66. When the threaded shaft 68 rotates, the moving body 61 moves together with the nut 67 in the axial direction of the threaded shaft 68, that is, the opening and closing direction X. Since the second finger 5 is connected to the moving body 61 via the second spring 63, the second finger 5 moves in the opening and closing direction X in response to the moving body 61. At this time, the direction of movement of the second finger 5 in the opening and closing direction X depends on the direction of rotation of the electric motor 62. By switching the direction of rotation of the electric motor 62, the opening and closing of the second finger 5 is switched.

[0080] When the second finger 5 is open, the moving body 61 directly presses the second finger 5 in the opening direction of the opening and closing direction X. On the other hand, when the second finger 5 is closed, the moving body 61 presses the second finger 5 in the closing direction of the opening and closing direction X via the second spring 63. When the second finger 5 moves in the closing direction and contacts the first finger 3, the second finger 5 cannot move in the opening and closing direction X. However, the moving body 61 can continue to move after the second finger 5 is in a completely closed state. The moving body 61 can move in the closing direction in the opening and closing direction X by elastically deforming the second spring 63 even after the second finger 5 cannot move.

[0081] It should be noted that when the first finger 3 and the second finger 5 are used to hold the object so that the second finger 5 cannot move in the opening and closing direction X, the moving body 61 can still continue to move. Due to the independent movement of the moving body 61, the elastic force of the second spring 63 increases. Due to the increase in the elastic force of the second spring 63, the holding force of the first finger 3 and the second finger 5 is generated. In this way, the opening and closing actuator 6 can further move the moving body 61 after the second finger 5 contacts the object, and elastically deform the second spring 63 to increase the holding force.

[0082] 〔Constraint〕

[0083] like Figure 6 As shown, the restraint 7 has a stopper 71 and a first spring 72 capable of moving between a first position and a second position, wherein the first position is a position for restraining the first finger 3 and making it a restrained state, and the second position is a position for releasing the first finger 3 and making it a released state, and the first spring 72 applies force to the stopper 71 from the second position toward the first position side. Figure 6 The stopper 71 is located at the first position. The first spring 72 is an example of a first elastic member.

[0084] The stopper 71 is formed in a rod shape. A rubber contact 74 is provided at one end, i.e., the first end, of the stopper 71 in the longitudinal direction. A flange 71a is provided at the middle portion of the stopper 71 in the longitudinal direction. The stopper 71 is supported by a retainer 75 housed in the hand body 20 so as to be movable in the opening and closing direction X. The stopper 71 is supported by the retainer 75 in a state where the axis of the stopper 71 extends in the opening and closing direction X and the contact 74 faces the buffer 8. Specifically, the contact 74 faces the retainer 81 of the buffer 8.

[0085] The first position of the stopper 71 is the position of the stopper 71 when the contact 74 contacts the retainer 81 of the buffer 8. The second position of the stopper 71 is the position where the contact 74 leaves the retainer 81 in the opening and closing direction X, that is, the position where the contact 74 and the retainer 81 are not in contact.

[0086] The first spring 72 covers the outer periphery of the second end portion of the stopper 71, which is the end portion on the opposite side to the contact piece 74, and is arranged in a compressed state on the retainer 75. The first spring 72 presses the flange 71a of the stopper 71 toward the buffer 8 in the opening and closing direction X. The stopper 71 is urged in the opening and closing direction X by the first spring 72, so that the stopper 71 presses the contact piece 74 against the retainer 81 of the buffer 8 at the first position, thereby restricting the movement of the buffer 8.

[0087] The restrainer 7 may also include an operating rod 76, which is connected to the stopper 71 and is arranged on the moving track of the moving body 61. In detail, the operating rod 76 is connected to the stopper 71 via a connecting rod 77. The connecting rod 77 has a first end 77a and a second end 77b. The middle part of the first end 77a and the second end 77b in the connecting rod 77 is mounted on the retainer 75 via a pin 77c. The connecting rod 77 can rotate relative to the retainer 75 with the pin 77c as the center. A pin 71b is provided between the contact piece 74 and the flange 71a in the stopper 71. The pin 71b is inserted into a long hole formed in the first end 77a of the connecting rod 77. In this way, the first end 77a of the connecting rod 77 is connected to the stopper 71. The operating rod 76 is mounted on the second end 77b of the connecting rod 77 via a pin 77d. The operating rod 76 extends from the connecting rod 77 in the bending direction. For example, the operating rod 76 extends from the second end 77b of the connecting rod 77 toward the moving body 61 side along the substantially opening and closing direction X2. It should be noted that the operating rod 76 can rotate with respect to the connecting rod 77 around the pin 77d. However, the rotation range of the operating rod 76 is limited by the connecting rod 77. Therefore, the operating rod 76 is maintained in a state of extending from the connecting rod 77 in the bending direction.

[0088] The front end of the operating rod 76, that is, the end on the opposite side to the connecting rod 77, is arranged on the moving trajectory of the moving body 61. In detail, the front end of the operating rod 76 is located on the moving trajectory of the moving body 61 from the time when the first finger 3 and the second finger 5 are in a completely closed state to the time when the second spring 63 is elastically deformed. In more detail, when the first finger 3 and the second finger 5 are in a completely closed state and the gripping force of the first finger 3 and the second finger 5 increases to a predetermined threshold value, the front end of the operating rod 76 is located at a position in contact with the arm 61a of the moving body 61.

[0089] like Figure 6 As shown, in the restraint 7 constructed as above, when the first finger 3 and the second finger 5 are in the open state, the arm 61a of the moving body 61 does not contact the operating rod 76. At this time, the stopper 71 is arranged in the first position due to the elastic force of the first spring 72. The contact member 74 of the stopper 71 is pressed against the retainer 81 of the buffer 8 by a force in response to the elastic force of the first spring 72. The buffer 8 becomes a state in which it cannot move in the first direction Z relative to the hand body 20. Since the first finger 3 is supported by the hand body 20 via the buffer 8, the movement of the first finger 3 in the first direction Z is also restricted. This state is the restrained state of the restraint 7. However, although the buffer 8 cannot move relative to the hand body 20, the first finger 3 can still move relative to the buffer 8. That is, even in the restrained state of the restraint 7, the first finger 3 can move in the first direction Z relative to the buffer 8 within the range of relative movement.

[0090] The switching between the restraining state and the released state of the restraint 7 is performed by the opening and closing actuator 6. The opening and closing actuator 6 moves the restraint 7 from the first position to the second position side against the elastic force of the first spring 72 when the second finger 5 is moved in the opening and closing direction X in a direction close to the first finger 3, so that the restraint 7 is in the released state. The opening and closing actuator 6 puts the restraint 7 in the fully closed state by moving the second finger 5 in the opening and closing direction X, more specifically, by moving the second finger 5 in the opening and closing direction X in a manner close to the first finger 3 and contacting the first finger 3, and then moving the moving body 61, so that the restraint 7 is in the released state.

[0091] Specifically, the electric motor 62 moves the moving body 61 so that the second finger 5 moves in the opening and closing direction X. When the moving body 61 moves in the closing direction of the second finger 5 in the opening and closing direction X, the second finger 5 also moves in the closing direction together with the moving body 61. In this way, the arm 61a approaches the operating rod 76. When the second finger 5 contacts the first finger 3, the second finger 5 cannot move further in the opening and closing direction X. Fig.10 is the hand 2 in the fully closed state, equivalent to Figure 5 When the first finger 3 and the second finger 5 are in the fully closed state, the arm 61a has not yet come into contact with the operating rod 76.

[0092] After the second finger 5 contacts the first finger 3, the moving body 61 can still move further by causing the second spring 63 to deform elastically. When the moving body 61 moves further in the closing direction from the fully closed state of the first finger 3 and the second finger 5, the arm 61a finally contacts the operating rod 76 and presses the operating rod 76 in the closing direction of the opening and closing direction X. That is, the opening and closing actuator 6 moves from the first position to the second position side by the moving body 61 causing the stopper 71 to resist the elastic force of the first spring 72. At this time, the second finger 5 contacts the first finger 3 and stops, and only the moving body 61 moves.

[0093] Fig.11 is the position of the hand 2 when the restraint 7 switches from the restraint state to the release state, which is equivalent to Figure 6 sectional view. By moving the operating rod 76 in the closing direction of the opening and closing direction X, the connecting rod 77 is rotated around the pin 77c in such a manner that the second end 77b of the connecting rod 77 moves in the closing direction substantially in the opening and closing direction X. As a result, the first end 77a of the connecting rod 77 moves in the opening direction substantially in the opening and closing direction X, and in response thereto, the stopper 71 moves in the direction away from the buffer 8 in the opening and closing direction X against the elastic force of the first spring 72. In this way, the stopper 71 moves from the first position to the second position.

[0094] When the stopper 71 is located at the second position, the contact member 74 becomes a retainer 81 that does not contact the buffer 8, and the buffer 8 is released from the restraint of the stopper 71. In this way, the buffer 8 is in a state where it can move relative to the hand body 20 in the first direction Z. Since the first finger 3 is supported by the hand body 20 via the buffer 8, the first finger 3 can also move in the first direction Z. This state is a released state of the restrainer 7.

[0095] 〔Control device〕

[0096] Fig.12 1 is a block diagram showing a schematic hardware configuration of the control device 120 . The control device 120 includes a control unit 121 , a storage unit 122 , and a memory 123 .

[0097] The control unit 121 controls the entire control device 120. The control unit 121 performs various calculations. For example, the control unit 121 is formed by a processor such as a CPU (central processing unit). The control unit 121 can also be formed by an MCU (microcontroller unit), an MPU (microprocessor unit), an FPGA (field programmable gate array), a PLC (programmable logic controller), a system LSI, etc.

[0098] The storage unit 122 stores programs and various data executed by the control unit 121. For example, the storage unit 122 stores a control program. The storage unit 122 is formed of a nonvolatile memory, a HDD (hard disk drive) or an SSD (solid state drive), etc. The memory 123 temporarily stores data, etc. The memory 123 is formed of a volatile memory, for example.

[0099] The control unit 121 realizes various functions of the control device 120 by reading and developing a program from the storage unit 122 into the memory 123 .

[0100] The control unit 121 controls the movement of the robot arm 1 by controlling each electric motor of the robot arm 1. The control unit 121 controls the electric motor according to the detection result of the encoder of the robot arm 1. In addition, the control unit 121 controls the movement of the hand 2 by controlling the advance and retreat actuator 4 and the opening and closing actuator 6. In detail, the control unit 121 drives the belt 35 by controlling the electric motor 42 according to the detection result of the position acquisition sensor 44. The control unit 121 drives the belt 35 to make the hand 2 perform any one of the movement of the object and the advance and retreat of the first finger 3. The control unit 121 moves the second finger 5 in the opening and closing direction X by controlling the electric motor 62 according to the detection result of the position acquisition sensor 64b.

[0101] 〔Hand Movement〕

[0102] The hand 2 constructed in this way is controlled by the control device 120 to perform a gripping action and a moving action. In the gripping action, the first finger 3 and the second finger 5 grip an object. In the moving action, the belt 35 of the first finger 3 moves the object. In addition, the hand 2 performs an advance and retreat action of moving the first finger 3 forward and backward in the first direction Z. The hand 2 adjusts the position of the first finger 3 in the first direction Z by the advance and retreat action.

[0103] 〔Advance and retreat movement〕

[0104] First, the advance and retreat movements of the opponent 2 will be described. Fig.13 It is used to explain the hand 2 of the forward and backward movement, which is equivalent to Figure 6 sectional view. In the hand 2, the advance / retract actuator 4 advances / retracts the first finger 3. As described above, the advance / retract actuator 4 drives the belt 35. The movement of the belt 35 is used for the advance / retract of the first finger 3 and the movement of the object. That is, the advance / retract actuator 4 alternatively performs the function of advancing / retracting the first finger 3 (hereinafter referred to as the "advance / retract function") and the function of moving the object (hereinafter referred to as the "movement function"). The advance / retract function and the movement function of the advance / retract actuator 4 are switched by the restraint 7. When the restraint 7 is in the released state, the advance / retract actuator 4 performs the advance / retract function, and when the restraint 7 is in the restrained state, the advance / retract actuator 4 performs the movement function.

[0105] Specifically, when the hand 2 performs the forward and backward motion, the restrainer 7 is released, and the first finger 3 is in a state where it can move in the first direction Z. In addition, the hand 2 makes the belt 35 of the first finger 3 contact another object. In this state, the hand 2 drives the belt 35 with the forward and backward actuator 4 to perform the forward and backward motion.

[0106] As described above, when the restraint 7 is in the released state, the belt 35 contacts the second finger 5. That is, the second finger 5 functions as an object that the belt 35 contacts when the first finger 3 is moved forward and backward. In this state, the advance and retreat actuator 4 drives the belt 35 by operating the electric motor 42. When the belt 35 is driven, the portion of the belt 35 that forms the contact surface 35a moves relative to the finger body 30 in the in-plane direction of the contact surface 35a. The portion of the belt 35 that forms the contact surface 35a contacts the second finger 5. Frictional force is generated between the contact surface 35a and the second finger 5. Therefore, even if the belt 35 is driven, the belt 35 does not slide relative to the second finger 5, or the sliding of the belt 35 relative to the second finger 5 is reduced, and instead, as shown in FIG. Fig.13 As shown, the finger body 30 moves relative to the second finger 5 in the first direction Z. That is, the first finger 3 moves relative to the second finger 5 in the first direction Z. When the first finger 3 reaches the desired position in the first direction Z, the advance and retreat actuator 4 stops the electric motor 42 to stop the advance and retreat of the first finger 3.

[0107] The rotation direction of the electric motor 42 is switched so that the first finger 3 is switched forward and backward relative to the hand body 20. In response to the state in which the holding action or the moving action is performed, the position of the first finger 3 in the first direction Z is adjusted. Basically, in the holding action, the position of the first finger 3 in the first direction Z is aligned with the second finger 5. In the moving action, the first finger 3 is in a state of protruding more than the second finger 5 in the first direction Z.

[0108] Fig.14 2 is a schematic front view of the hand 2 for explaining the movement when the forward and backward movement is completed. After the position of the first finger 3 in the first direction Z is adjusted by the forward and backward movement, the opening and closing actuator 6 moves the moving body 61 in the opening and closing direction X in a direction away from the first finger 3, as shown in FIG. Fig.14 As shown, the contact between the moving body 61 and the operating rod 76 is eliminated. In this way, the stopper 71 moves to the first position due to the elastic force of the first spring 72, and the contact member 74 contacts the retainer 81 of the buffer 8. In this way, the restrainer 7 switches from the release state to the restraining state.

[0109] 〔Holding action〕

[0110] Next, the gripping action of the hand 2 will be described. Fig.15 2 is a schematic front view of the hand 2 for explaining the holding action. When the hand 2 performs the holding action, the position of the first finger 3 in the first direction Z is basically adjusted in such a way that the fingertip of the first finger 3 and the fingertip of the second finger 5 in the first direction Z are roughly aligned. Fig.15 As shown by the two-dot chain line, the hand 2 sets the second finger 5 away from the first finger 3 in the second direction X, that is, the first finger 3 and the second finger 5 are open. It should be noted that, depending on the usage conditions, the fingertip of the first finger 3 and the fingertip of the second finger 5 in the first direction Z may not be aligned.

[0111] Typically, the robot arm 1 moves the hand 2 so that the first finger 3 and the second finger 5 approach the surface (hereinafter referred to as the "support surface") P on which the article W is placed from the first direction Z. The hand 2 is moved so that the article W is located between the first finger 3 and the second finger 5. Next, the hand 2 moves the second finger 5 close to the first finger 3 through the opening and closing actuator 6. The opening and closing actuator 6 causes the electric motor 62 to operate in a direction corresponding to the closing action of the second finger 5. Through the rotation of the electric motor 62, the second finger 5 moves in the closing direction in the opening and closing direction X together with the moving body 61 and the nut 67. The second finger 5 eventually contacts the article W and pushes the article W in the closing direction until it contacts the first finger 3. Finally, the first finger 3 and the second finger 5 hold the article W by the contact surface 35a and the contact surface 54a. It should be noted that during the holding action, the advance and retreat actuator 4 does not operate and the belt 35 of the first finger 3 does not move.

[0112] Fig.16 This is a hand 2 for explaining the action of the buffer 8, which is equivalent to Figure 5 sectional view. As described above, when the first finger 3 and the second finger 5 approach the supporting surface P or other objects such as the article W, sometimes the front end of the first finger 3 or the second finger 5 contacts the supporting surface P, etc. Since the first finger 3 is elastically supported by the buffer 8, it can retreat toward the hand body 20 side in the first direction Z. The impact acting on the first finger 3 from the supporting surface P moves in the first direction Z through the first finger 3 and is absorbed by the third spring 83 of the buffer 8. Since the fingertip 54 of the second finger 5 is elastically supported by the finger body 50 via the spring 56, it can retreat toward the hand body 20 side in the first direction Z. The impact acting on the second finger 5 from the supporting surface P, etc. moves in the first direction Z through the fingertip 54 and is absorbed by the spring 56. In this way, either the first finger 3 or the second finger 5 can absorb the impact in the first direction Z.

[0113] (Move Action)

[0114] Next, the movement of the hand 2 is described. When the hand 2 performs the movement, in order to enable the forward and backward actuator 4 to perform the movement function, the restraint 7 is set to the restraint state. Fig.14 As shown, the hand 2 moves the second finger 5 away from the first finger 3 in the opening and closing direction X. In this state, the advance and retreat actuator 4 drives the belt 35. Since the first finger 3 cannot move in the first direction Z, the portion of the belt 35 that forms the contact surface 35a moves in the first direction Z. When the object contacts the contact surface 35a and the friction force acts between the contact surface 35a and the object, the object moves together with the contact surface 35a in the first direction Z. The hand 2 switches the moving direction of the object by the rotation direction of the electric motor 42 of the advance and retreat actuator 4.

[0115] According to the moving action, the object can be moved only by the first finger 3, without holding the object with the first finger 3 and the second finger 5. In this way, even if the space around the object is narrow and it is difficult to get multiple fingers close to the object or the object cannot be held from both sides, the object can be moved by only touching the object with the first finger 3. Fig.14 As shown, by making the tip of the first finger 3 protrude further in the first direction Z than the tip of the second finger 5 , the first finger 3 can be easily inserted into a narrow space, and the first finger 3 can reach the object more easily.

[0116] 〔Pull in and hold〕

[0117] First, the pull-in gripping is described, in which the object is pulled between the first finger 3 and the second finger 5 and then gripped by the first finger 3 and the second finger 5 . Fig.17 It is an explanatory diagram for explaining the state of the hand 2 at the start of pulling and grasping. Fig.18 It is an explanatory diagram for explaining the hand 2 in the middle of pulling and grasping. Fig.19 2 is an explanatory diagram for explaining the state of the hand 2 when the pull-in grip is completed. Fig.17 , Fig.18 as well as Fig.19 In the pulling-in grasping, one object W is pulled into the hand 2 from among a plurality of overlapping plate-shaped objects W and grasped.

[0118] For example, a plurality of plate-shaped articles W are stacked and stored in a standing state in a tray T. During the pulling and holding, the article W arranged on the outermost side in the stacking direction is taken out. For the sake of convenience, the plurality of articles W are referred to as the first article W1, the second article W2, the third article W3, etc., starting from the outermost side.

[0119] like Fig.17 As shown, the hand 2 is pre-set to a state where the first finger 3 protrudes a predetermined amount in the first direction Z compared to the second finger 5 and the interval between the first finger 3 and the second finger 5 in the opening and closing direction X is slightly larger than the thickness of the article W. In this state, the hand 2 is moved to a position where the first finger 3 contacts the first article W1. Specifically, the contact surface 35a of the first finger 3 contacts the surface of the first article W1 that is exposed to the outside in the stacking direction (hereinafter, this surface is referred to as the "outermost surface f1"). The second finger 5 is arranged at a position where it does not contact the end surface of the second article W2.

[0120] The hand 2 operates the advance / retract actuator 4 to drive the belt 35. At this time, since the restraint 7 is in the restrained state, the advance / retract actuator 4 performs the moving function. When the belt 35 is driven in this state, the portion of the belt 35 that forms the contact surface 35a moves in the in-plane direction of the contact surface 35a. Along with this, the first object W1 that contacts the belt 35 also moves together with the belt 35. Here, the rotation direction of the electric motor 42 is set so that the portion of the belt 35 that forms the contact surface 35a moves in the first direction Z toward the hand body 20, that is, in the upward direction in the figure. As a result, the first object W1 is pulled between the first finger 3 and the second finger 5.

[0121] like Fig.18 As shown, when the first object W1 is pulled into the gap between the first finger 3 and the second finger 5, the advance / retract actuator 4 stops driving the belt 35. At this time, the second object W2 may move in the first direction Z together with the first object W1 due to the friction between the first object W1 and the second object W2. However, the second finger 5 is located in the first direction Z of the second object W2. Therefore, the end face of the second object W2 moving in the first direction Z contacts the front end of the second finger 5. As a result, only the first object W1 is pulled in between the first finger 3 and the second finger 5, and the second object W2 is not pulled in between the first finger 3 and the second finger 5.

[0122] It should be noted that by adjusting the interval between the first finger 3 and the second finger 5 , it is possible to pull multiple objects W between the first finger 3 and the second finger 5 , for example, pull both the first object W1 and the second object W2 between the first finger 3 and the second finger 5 .

[0123] Then, the hand 2 causes the opening and closing actuator 6 to operate, as shown in FIG. Fig.19 As shown, the second finger 5 is closed. The second finger 5 moves toward the first finger 3 in the opening and closing direction X, and the first finger 3 and the second finger 5 hold the first article W1. In this way, the pull-in holding is completed.

[0124] When the pull-in grip is completed, the robot arm 1 moves the hand 2 to take out the first object W1 from the tray T.

[0125] In this way, even if only one of the two surfaces of the object W to be held by the first finger 3 and the second finger 5 is exposed to the outside, the object W can be moved together with the belt 35 by driving the belt 35 in a state where the belt 35 of the first finger 3 is in contact with the surface exposed to the outside. For example, the belt 35 can be driven in a state where the belt 35 of the first finger 3 is in contact with the outermost surface f1.

[0126] It should be noted that, in the example of the tray T, the hand 2 pulls the object W between the first finger 3 and the second finger 5, but the moving direction of the object W is not limited to this. For example, although it depends on the conditions around the object W, the belt 35 may be moved in the opposite direction to the direction when the object W is pulled in, so as to release the objects W one by one. After the objects W are released one by one, the hand 2 may move to hold the objects W by the first finger 3 and the second finger 5, or the objects W may be held by another hand or the like.

[0127] Furthermore, the plurality of objects W are arranged in the horizontal direction, but this is not limited to this. For example, even when the plurality of objects W are arranged and stacked in the vertical direction, the hand 2 can hold the object W by pulling it in and holding it. For example, the hand 2 is moved in such a way that the first finger 3 contacts the upwardly exposed surface of the object W located at the top of the plurality of objects W stacked in the vertical direction. That is, the posture of the hand 2 is adjusted in such a way that the first direction Z is oriented in the horizontal direction. The hand 2 thereafter is as described above. The top object W is held by the first finger 3 and the second finger 5 after being pulled in between the first finger 3 and the second finger 5 in the horizontal direction.

[0128] 〔Pull in〕

[0129] Next, simple pulling-in of the object W by the first finger 3 will be described. Fig. 20 2 is an explanatory diagram for explaining an example of pulling in an article W by the hand 2. For example, an article W is placed on a shelf S. In this example, the article W is a book.

[0130] The hand 2 is pre-set to a state where the first finger 3 protrudes a predetermined amount in the first direction Z compared to the second finger 5 and the first finger 3 and the second finger 5 are opened in the opening and closing direction X. In this state, the hand 2 is moved to a position where the first finger 3 enters the gap between the shelf S and the article W and the contact surface 35a of the first finger 3 contacts the end surface of the article W. It should be noted that the second finger 5 does not contact the article W.

[0131] The hand 2 operates the advance / retract actuator 4 to drive the belt 35. Since the restraint 7 is in the restrained state, the advance / retract actuator 4 performs the moving function. When the belt 35 is driven, the portion of the belt 35 that forms the contact surface 35a moves in the in-plane direction of the contact surface 35a. In detail, the rotation direction of the electric motor 42 is set so that the portion of the belt 35 that forms the contact surface 35a moves in the first direction Z toward the hand body 20. Along with this, the object W that contacts the belt 35 also moves in the first direction Z toward the hand body 20 side together with the belt 35. As a result, the object W is pulled from the shelf S to the hand body 20 side.

[0132] After the article W is pulled out from the shelf S, the hand 2 makes the front ends of the first fingers 3 and the second fingers 5 substantially coincide with each other in the first direction Z, and grasps the pulled-out portion of the article W with the first fingers 3 and the second fingers 5 .

[0133] Next, another example of simple pulling-in of the article W by the first finger 3 will be described. Fig.21 2 is an explanatory diagram for explaining another example of pulling in an article W by the hand 2. For example, the article W is placed on the tray T. In this example, the article W close to the side wall of the tray T is moved toward the center by pulling in by the hand 2.

[0134] The hand 2 is preset to a state where the first finger 3 protrudes a predetermined amount in the first direction Z compared to the second finger 5, and the first finger 3 and the second finger 5 are opened in the opening and closing direction X. In addition, the hand 2 is in a posture where the first direction Z is inclined relative to the vertical direction. In this state, the hand 2 is moved to a position where the front end of the first finger 3 contacts the article W close to the side wall of the tray T.

[0135] The hand 2 is moved toward the center side of the tray T in a state where the belt 35 at the front end of the first finger 3 contacts the article W. In this way, the article W contacted by the first finger 3 is moved toward the center side of the tray T together with the first finger 3. At this time, the hand 2 may also operate the advance / retract actuator 4. The advance / retract actuator 4 moves the belt 35 in a direction to move the article W toward the center side of the tray T. In addition to the movement of the first finger 3, the movement of the belt 35 promotes the movement of the article W toward the center of the tray T. The movement of the hand 2 is continued until the article W leaves the side wall of the tray T and a space is secured between the article W and the side wall of the tray T, for example, until a space is secured between the article W and the side wall of the tray T into which the first finger 3 can enter.

[0136] After ensuring a space between the article W and the side wall of the tray T, the hand 2 makes the front ends of the first fingers 3 and the second fingers 5 substantially coincide with each other in the first direction Z, and grasps the article W with the first fingers 3 and the second fingers 5 .

[0137] As described above, since the first finger 3 provided with the belt 35 in the hand 2 moves forward and backward in the first direction Z, the range of use of the belt 35 can be expanded, and the convenience of the first finger 3 can be improved. For example, by making the first finger 3 protrude more than the second finger 5 in the first direction Z, the first finger 3 can reach the object more easily even if the space around the object is narrow. By driving the belt 35 in a state where the belt 35 of the first finger 3 is in contact with the object, the object can be moved together with the belt 35. In other words, the object can be moved without being grasped by the first finger 3 and the second finger 5. In addition, after moving the object to an appropriate place, the object can be grasped by the first finger 3 and the second finger 5.

[0138] As described above, the method of moving the object by the belt 35 of the first finger 3 includes a method of pulling the object between the first finger 3 and the second finger 5, a method of simply pulling the object toward the hand body 20, and a method of moving the object by driving the belt 35 while moving the entire first finger 3.

[0139] Furthermore, it is also possible to combine the movement of the object by the belt 35 and the gripping by the first finger 3 and the second finger 5. For example, as described above, after the object is pulled between the first finger 3 and the second finger 5 by the belt 35, the object may be gripped by the first finger 3 and the second finger 5. The object may also be moved between the first finger 3 and the second finger 5 by the belt 35 while the object is being gripped by the first finger 3 and the second finger 5.

[0140] Thus, by making the first finger 3 independently movable in the first direction Z from the second finger 5 , the position of the first finger 3 relative to the second finger 5 in the first direction Z can be adjusted. Thus, the range of use of the first finger 3 provided with the belt 35 can be expanded.

[0141] Furthermore, regarding the hand 2, the driving source for moving the first finger 3 forward and backward in the first direction Z is the same as the driving source for the belt 35. That is, the forward and backward actuator 4 drives the belt 35, and the movement of the belt 35 is used alternately for the forward and backward movement of the first finger 3 and the movement of the object. In this way, the number of parts of the hand 2 can be reduced, the structure can be simplified, and the cost can be reduced.

[0142] Specifically, the hand 2 has a restraint 7, and the advance / retract function and the movement function of the belt 35 are switched by switching the restraint state and the release state of the first finger 3 by the restraint 7, and the restraint 7 restrains the movement of the first finger 3 in the first direction Z. By providing the restraint 7, both the advance / retract movement of the first finger 3 and the movement of the object can be realized by the common advance / retract actuator 4.

[0143] Furthermore, when the first finger 3 is moved forward and backward, the belt 35 is driven by the advancing and retreating actuator 4 in a state where the restrainer 7 is in a released state and the belt 35 is in contact with another object. By driving the belt 35 in a state where the belt 35 is in contact with another fixed object, the first finger 3 is moved in the first direction Z relative to the other object. The hand 2 uses the second finger 5 as another object that contacts the belt 35. Since the second finger 5 can move in the opening and closing direction X, when the first finger 3 is moved forward and backward, the hand 2 makes the first finger 3 and the second finger 5 in a completely closed state, and makes the second finger 5 contact the belt 35 of the first finger 3. Since the second finger 5 cannot move forward and backward in the first direction Z, the belt 35 is driven in a state where the belt 35 is in contact with the second finger 5, so that the first finger 3 is moved forward and backward in the first direction Z. In this way, it is not necessary to move the hand 2 in a manner that the belt 35 contacts another fixed object. By using the second finger 5 that the hand 2 originally has for holding an object, the first finger 3 can be moved forward and backward more easily.

[0144] Furthermore, the hand 2 switches the restraint state and the release state of the restraint 7 by the opening and closing action of the second finger 5. Specifically, the moving body 61 that moves in conjunction with the opening and closing of the second finger 5 switches the restraint state and the release state of the restraint 7. In this way, there is no need to separately provide a driving source for switching the restraint state and the release state of the restraint 7. In other words, the driving force of the opening and closing actuator 6 can be used to switch the restraint state and the release state of the restraint 7.

[0145] Furthermore, by switching the restraint 7 by using the opening and closing motion of the second finger 5, the switching timing of the restraint 7 can be coordinated with the opening and closing timing of the second finger 5. For example, when the second finger 5 is used as another object that the belt 35 contacts in order to move the first finger 3 forward and backward, the second finger 5 needs to be in a completely closed state and the restraint 7 needs to be in a released state. By switching the restraint 7 by using the opening and closing motion of the second finger 5, such a situation can be easily achieved.

[0146] In addition, the opening and closing actuator 6 that drives the second finger 5 has a moving body 61 and a second spring 63. From the completely closed state of the first finger 3 and the second finger 5, the moving body 61 is further moved against the elastic force of the second spring 63, so that the moving body 61 switches the restraint 7 from the restrained state to the released state. The moving body 61 is driven in the opening and closing direction X, and the second spring 63 elastically connects the moving body 61 and the second finger 5.

[0147] That is, the moving body 61 has a function of moving each of the second finger 5 and the stopper 71. By connecting the moving body 61 and the second finger 5 via the second spring 63, the moving body 61 can be further moved after the first finger 3 and the second finger 5 are in a completely closed state. While the second finger 5 is not in contact with the first finger 3, the moving body 61 moves only the second finger 5 and does not move the stopper 71. When the second finger 5 contacts the first finger 3, the second finger 5 stops and only the moving body 61 moves. When the moving body 61 moves while the second finger 5 stops, the moving body 61 moves the stopper 71. That is, in the section of further movement of the moving body 61 after the second finger 5 contacts the first finger 3, the moving body 61 releases the restraint 7.

[0148] In this way, in the fully closed state of the first finger 3 and the second finger 5, the restraint state and the release state of the restraint 7 are switched according to the position of the moving body 61. At the moment when the first finger 3 and the second finger 5 are in the fully closed state, the restraint 7 is still in the restraint state. In this way, when the first finger 3 and the second finger 5 hold the object in a state close to the fully closed state, such as when holding a thin sheet-like object, the restraint 7 can be prevented from being in the release state. Specifically, the opening and closing actuator 6 moves the moving body 61 to a position where the second finger 5 contacts the first finger 3 and the moving body 61 does not contact the stopper 71. In this way, when the restraint 7 is maintained in the restraint state, the first finger 3 and the second finger 5 are in the fully closed state. On the other hand, the opening and closing actuator 6 moves the moving body 61 to a position where the second finger 5 contacts the first finger 3 and the moving body 61 presses the stopper 71 to the second position. In this way, in the fully closed state of the first finger 3 and the second finger 5, the restraint 7 is in the release state. In this manner, the opening and closing actuator 6 can appropriately switch the restraining state and the releasing state of the restraint device 7 according to the position of the moving body 61 in the fully closed state of the first finger 3 and the second finger 5 .

[0149] 《Other Implementation Methods》

[0150] As described above, the embodiments are described as examples of the technology disclosed in this application. However, the technology disclosed in the present invention is not limited thereto, and can also be applied to embodiments that have been appropriately changed, replaced, added, omitted, etc. Furthermore, the various constituent elements described in the embodiments can also be combined as new embodiments. Furthermore, the constituent elements recorded in the drawings and detailed descriptions include not only the constituent elements necessary to solve the problem, but also constituent elements that are not necessary to solve the problem in order to exemplify the technology. Therefore, it should not be immediately assumed that those non-essential constituent elements are necessary just because they are recorded in the drawings and detailed descriptions.

[0151] For example, the hand 2 may not be connected to the robot arm 1 . The hand 2 may be applied to a dedicated machine or the like instead of the robot 110 .

[0152] The hand 2 may have other fingers instead of the second finger 5. The hand 2 may include more than three fingers. In other words, the hand 2 only needs to include fingers that can move forward and backward relative to the hand body independently of the other fingers.

[0153] It is sufficient that at least one of the first finger 3 and the second finger 5 can move in the second direction X. For example, the first finger 3 can be provided on the hand body 20 so as to be movable in the second direction X, and the second finger 5 cannot be provided on the hand body 20 so as to be movable in the second direction X. Alternatively, both the first finger 3 and the second finger 5 can be provided on the hand body 20 so as to be movable in the second direction X. Alternatively, when the first finger 3 can move in the second direction X, the opening and closing actuator 6 can move the first finger 3 in the second direction X relative to the hand body 20 in conjunction with the second finger 5 or independently from the second finger 5.

[0154] It may also be a finger other than the first finger 3, for example, the second finger 5 is provided on the hand body 20 so as to be able to move forward and backward in the first direction Z. For example, it may also be possible for all fingers of the hand 2 to be able to move forward and backward in the first direction Z. In that case, it is sufficient as long as at least one finger provided with the belt can move forward and backward in the first direction Z independently of the other fingers.

[0155] Alternatively, a finger other than the first finger 3 , for example, the second finger 5 , may be provided with a belt having a contact surface for contacting an object.

[0156] The advance / retract actuator for advancing / retracting the first finger 3 is not limited to the drive belt 35, and is a device for advancing / retracting the first finger 3 by the action of the belt 35. The advance / retract actuator may be provided separately from the actuator for the drive belt 35. For example, the advance / retract actuator may be a linear actuator for advancing / retracting the first finger 3.

[0157] As described above, in the structure in which the first finger 3 is moved forward and backward by the movement of the belt 35, the other object that is brought into contact with the belt 35 is not limited to the second finger 5. For example, the first finger 3 may be moved forward and backward by driving the belt 35 while the belt 35 is brought into contact with a fixed object such as a support table or a tray that supports an article.

[0158] Furthermore, the first finger 3 may be moved to a position where the front end is further back in the first direction Z than the front end of the second finger 5 .

[0159] The restraint 7 is not limited to the above-described structure. The restraint state and the release state of the restraint 7 may be switched by an actuator other than the opening and closing actuator 6. For example, the hand 2 may include a dedicated actuator for switching the state of the restraint 7.

[0160] The timing of switching the restraint 7 from the restrained state to the released state can be set arbitrarily. The timing of switching to the released state can also be when the first finger 3 and the second finger 5 are in a completely closed state. Alternatively, the first finger 3 and the second finger 5 can be switched to the released state at any time in the open state. The timing of switching the restraint 7 from the restrained state to the released state can be set arbitrarily in the above-mentioned structure composed of the opening and closing actuator 6 by changing the positional relationship between the moving body 61 and the operating rod 76. In the structure in which the state of the restraint 7 is switched by a dedicated actuator, the state of the restraint 7 can be switched at any time.

[0161] The application of the first finger 3 is not limited to the above examples. The first finger 3 can be used alone, or can be used in cooperation with other fingers such as the second finger 5, and can be used in various situations. For example, in a holding action, the front end of the first finger 3 and the front end of the second finger 5 in the first direction Z may not be aligned. In a moving action, the front end of the first finger 3 and the front end of the second finger 5 in the first direction Z may also be aligned.

[0162] The functions implemented by the components described in this specification may also be implemented in a circuit or processing circuitry that includes a general-purpose processor, a special-purpose processor, an integrated circuit, an ASIC (Application Specific Integrated Circuits), a CPU (a Central Processing Unit), a conventional circuit, and / or a combination thereof that is programmed to implement the described functions. The processor includes transistors and other circuits and is considered a circuit or processing circuit. The processor may also be a programmable processor that executes a program stored in a memory.

[0163] In this specification, circuits, units, and devices are hardware programmed or executed to implement the functions described. The hardware may also be various hardware disclosed in this specification or various hardware well known as hardware programmed or executed to implement the functions described.

[0164] When the hardware is a processor of a type regarded as a circuit, the circuit, device or unit is a combination of hardware and software used to constitute the hardware and / or processor.

[0165] The technology of the present invention is summarized below.

[0166] [1] The hand 2 includes a hand body 20, a first finger 3, a second finger 5 and an advance / retract actuator 4, wherein the first finger 3 is arranged on the hand body 20, and the second finger 5 is arranged on the hand body 20. The advance / retract actuator 4 enables the first finger 3 to advance / retract independently from the second finger 5 relative to the hand body in a specified first direction Z. The first finger 3 has a belt 35, and the belt 35 forms a contact surface 35a with an object and moves in the in-plane direction of the contact surface 35a.

[0167] According to this structure, the tip of the first finger 3 and the tip of the second finger 5 can be aligned or offset in the first direction Z by making the first finger 3 advance and retreat independently from the second finger 5. For example, when the space around the article is narrow or when the article is handled only by the belt 35 of the first finger 3, the first finger 3 can be made to protrude more than the second finger 5 in the first direction Z, so that the first finger 3 can easily reach the article. Or, when the article is handled by the first finger 3 and the second finger 5, the tip of the first finger 3 and the tip of the second finger 5 can be aligned in the first direction Z, so that the belt 35 can easily apply an action to the article in a state where the first finger 3 and the second finger 5 hold the article. In this way, the hand 2 can change the position of the first finger 3 relative to the second finger 5 in the first direction Z in response to the situation around the article and the method of handling the article by the hand 2. By changing the position of the first finger 3 in the first direction Z, the hand 2 can appropriately and easily handle the article. As a result, the first finger 3 provided with the belt 35 can be used more effectively, and the convenience of the first finger 3 can be improved.

[0168] [2] In the hand 2 described in [1], the advance / retract actuator 4 drives the belt 35 so as to move the belt 35 in the in-plane direction of the contact surface 35 a.

[0169] According to this configuration, specifically, the advancing and retreating actuator 4 advances and retreats the first finger 3 in the second direction Z by driving the belt 35 .

[0170] [3] The hand 2 described in [1] or [2] further includes a restraint 7 which switches between a restraint state in which the first finger 3 cannot move in the first direction Z and a release state in which the first finger 3 can move in the first direction Z.

[0171] According to this configuration, the first finger 3 switches between a state in which it cannot move in the first direction Z and a state in which it can move in the first direction Z by the restraint 7 .

[0172] [4] In the hand 2 described in any one of [1] to [3], the advance / retract actuator 4 causes the first finger 3 to advance / retract in the first direction Z by driving the belt 35 when the restraint 7 is in a released state and the belt 35 is in contact with another object, and causes the object to move in the in-plane direction of the contact surface 35a by driving the belt 35 when the restraint 7 is in a restrained state and the belt 35 is in contact with another object.

[0173] According to this configuration, the advance / retract actuator 4 can switch between an advance / retract function of advancing / retracting the first finger 3 and a move function of moving an object by switching the release state and the restraint state of the restraint 7 .

[0174] [5] In the hand 2 described in any one of [1] to [4], the other object is a second finger 5.

[0175] According to this configuration, the advance / retract actuator 4 can relatively easily realize the advance / retract of the first finger 3 by utilizing the second finger 5. That is, in order to realize the advance / retract of the first finger 3, it is not necessary to search for another object for the first finger 3 to contact each time.

[0176] [6] The hand 2 described in any one of [1] to [5] also includes an opening and closing actuator 6, which causes at least one of the first finger 3 and the second finger 5 to move in a predetermined second direction X relative to the hand body 20 in a manner close to or away from the other of the first finger 3 and the second finger 5, and the restraint 7 has a stopper 71 and a first spring 72 (first elastic component), wherein the stopper 71 is movable between a first position for restraining the first finger 3 and a second position for releasing the first finger 3, and the first spring 72 (first elastic component) applies a force to the stopper 71 from the second position toward the first position side, and when the opening and closing actuator 6 causes at least one of the first finger 3 and the second finger 5 to move in the second direction X in a direction close to the other of the first finger 3 and the second finger 5, the stopper 71 moves from the first position to the second position side against the elastic force of the first spring 72, thereby releasing the restraint 7.

[0177] According to this configuration, the restraint 7 can be placed in the released state when the first finger 3 and the second finger 5 are closed.

[0178] [7] In the hand 2 described in any one of [1] to [6], the opening and closing actuator 6 sets the restraint 7 to the released state when the first finger 3 and the second finger 5 are in the fully closed state.

[0179] According to this structure, specifically, the restraint 7 is in the released state when the first finger 3 and the second finger 5 are in a completely closed state when they are closed. When the first finger 3 and the second finger 5 are in the completely closed state, the second finger 5 contacts the belt 35 of the first finger 3. By driving the belt 35 in this state, the first finger 3 is moved forward and backward in the first direction Z. In other words, by making the first finger 3 and the second finger 5 in the completely closed state, both the state in which the belt 35 contacts the second finger 5 and the released state of the restraint 7 can be achieved, and as a result, the first finger 3 can be moved forward and backward in the first direction Z.

[0180] [8] In the hand 2 described in any one of [1] to [7], the opening and closing actuator 6 has a movable body 61, a second spring 63 (second elastic component) and an electric motor 62 (driving source), wherein the second spring 63 (second elastic component) elastically connects the movable body 61 and the second finger 5, and the electric motor 62 (driving source) moves the movable body 61. By moving the movable body 61 by the electric motor 62, the second finger 5 is moved in the second direction X. After the second finger 5 contacts the first finger 3, the movable body 61 is further moved against the elastic force of the second elastic component, so that the movable body moves the stopper from the first position to the second position against the elastic force of the first elastic component, thereby releasing the restraint 7.

[0181] According to this structure, the restraint 7 is in the released state when the first finger 3 and the second finger 5 are in the fully closed state, and the movable body 61 elastically deforms the second spring 63 and moves further after the second finger 5 contacts the first finger. That is, by connecting the movable body 61 and the second finger 5 via the second spring 63, it is possible to move the movable body 61 even after the second finger 5 contacts the first finger 3, and the timing of the stopper 71 moving to the second position is later than the timing of the second finger 5 contacting the first finger 3. For example, when the hand 2 holds a very thin object, if the restraint 7 is in the released state while the object is held by the first finger 3 and the second finger 5, the holding of the object may become unstable. However, even when the first finger 3 and the second finger 5 are in the substantially fully closed state, the restraint 7 may not be in the released state depending on the position of the movable body 61. That is, it is possible to prevent the restraint 7 from being immediately released when the first finger 3 and the second finger 5 are in the fully closed state. Therefore, the state of holding the object by the first finger 3 and the second finger 5 is appropriately maintained.

[0182] [9] In the hand 2 described in any one of [1] to [8], the restraint 7 also has an operating rod 76, which is connected to the stopper 71 and is arranged on the moving trajectory of the moving body 61. The moving body 61 presses the operating rod 76 when it further moves against the elastic force of the second spring 63 after the second finger 5 contacts the first finger 3, so that the stopper 71 moves from the first position to the second position side against the elastic force of the first spring 72, thereby releasing the restraint 7.

[0183] According to this structure, the moving moving body 61 presses the operating rod 76, and the stopper 71 connected to the operating rod 76 moves from the first position to the second position side, and as a result, the restraint 7 is released. Here, the position of the operating rod 76 is set so that when the moving body 61 moves further after the second finger 5 contacts the first finger 3, the stopper 71 moves from the first position to the second position side. In this way, it is possible to realize a structure in which the restraint 7 is released when the moving body 61 moves further after the first finger 3 and the second finger 5 are in a completely closed state.

[0184]

[10] The hand 2 described in any one of [1] to [9] further includes a buffer 8 that elastically supports the first finger 3 so that it can move in the first direction Z relative to the hand body 20.

[0185] According to this structure, even if an impact in the first direction Z acts on the first finger 3, the buffer 8 can absorb the impact. For example, even if the hand 2 moves and the first finger 3 contacts another object from the first direction Z, the buffer 8 can absorb the impact from the other object to the first finger 3.

[0186]

[11] In the hand 2 described in any one of [1] to

[10] , the buffer 8 has a linear guide 82 and a third spring 83 (third elastic component), wherein the linear guide 82 guides the first finger 3 in the first direction Z, and the third spring 83 (third elastic component) elastically absorbs the movement of the first finger 3 in the first direction Z.

[0187] According to this structure, the first finger 3 can be elastically moved in the first direction Z by the linear guide 82 and the third spring 83. When an impact acts on the first finger 3, the first finger 3 is guided by the linear guide 82 and moves in the first direction Z, and the impact is absorbed by the third spring.

[0188]

[12] In the hand 2 described in any one of [1] to

[11] , the advance and retreat actuator 4 has an electric motor 42, the first finger 3 and the electric motor 42 are arranged in the first direction Z, the electric motor 42 is configured so that the rotation axis M of the electric motor 42 extends in the first direction Z, and the third spring 83 is a coil spring arranged around the outer periphery of the electric motor 42.

[0189] According to this structure, since the third spring 83 is arranged around the outer periphery of the electric motor 42, the shock absorber 8 can be arranged compactly. As a result, the hand 2 can be miniaturized.

Claims

1. A hand, characterized in that: The hand includes a hand body, a first finger, a second finger, and an advance / retract actuator, wherein the first finger is arranged on the hand body, the second finger is arranged on the hand body, and the advance / retract actuator enables the first finger to advance / retract independently from the second finger relative to the hand body in a predetermined first direction. The first finger has a belt that forms a contact surface with the object and moves in an in-plane direction of the contact surface.

2. The hand according to claim 1, characterized in that: The advance / retract actuator drives the belt to move the belt in an in-plane direction of the contact surface.

3. The hand according to claim 2, characterized in that: The hand further includes a restraint, which switches between a restraint state and a release state, wherein in the restraint state, the first finger cannot move in the first direction, and in the release state, the first finger can move in the first direction.

4. The hand according to claim 3, characterized in that: The advance and retreat actuator drives the belt in the released state of the restraint and in contact with another object to move the first finger forward and backward in the first direction, and drives the belt in the constrained state of the restraint and in contact with another object to move the object in the in-plane direction of the contact surface.

5. The hand according to claim 4, characterized in that: The other object is the second finger.

6. The hand according to any one of claims 3 to 5, characterized in that: The hand further includes an opening and closing actuator that causes at least one of the first finger and the second finger to move in a predetermined second direction relative to the hand body in a manner that the first finger approaches or moves away from the other of the first finger and the second finger. The restraint device includes a stopper and a first elastic component, wherein the stopper is movable between a first position for restraining the first finger and a second position for releasing the first finger, and the first elastic component applies force to the stopper from the second position toward the first position. The opening and closing actuator puts the restraint in the released state by causing the stopper to move from the first position toward the second position side against the elastic force of the first elastic component when at least one of the first finger and the second finger moves in the second direction toward the other direction approaching the first finger and the second finger.

7. The hand according to claim 6, characterized in that: The opening and closing actuator sets the restraint to the released state when the first finger and the second finger are in the fully closed state.

8. The hand according to claim 7, characterized in that: The opening and closing actuator includes a moving body, a second elastic member, and a driving source, wherein the second elastic member elastically connects the moving body and the second finger, and the driving source moves the moving body. The second finger is moved in the second direction by moving the moving body with the driving source, After the second finger contacts the first finger, the movable body is further moved against the elastic force of the second elastic member, so that the movable body moves the stopper from the first position to the second position against the elastic force of the first elastic member, and the restraint is in the released state.

9. The hand according to claim 8, characterized in that: The restraint device further comprises an operating rod, which is connected to the stopper and arranged on the moving track of the moving body. The movable body presses the operating rod when further moving against the elastic force of the second elastic member after the second finger contacts the first finger, so that the stopper moves from the first position to the second position against the elastic force of the first elastic member, and the restraint is in the released state.

10. The hand according to claim 1, characterized in that: The hand further includes a buffer that elastically supports the first finger so that the first finger can move in the first direction relative to the hand body.

11. The hand according to claim 10, characterized in that: The buffer includes a linear guide that guides the first finger in the first direction and a third elastic member that elastically absorbs movement of the first finger in the first direction.

12. The hand according to claim 11, characterized in that: The forward and backward actuator has an electric motor. The first finger and the electric motor are arranged in the first direction, The electric motor is configured such that the rotating axis of the electric motor extends in the first direction, The third elastic member is a coil spring disposed around the outer circumference of the electric motor.

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