Control agency

Abstract

To provide a gripping mechanism that allows an operator to easily predict the movement of a gripping member. [Solution] The gripping mechanism 10 includes a fixed link L0, a first link L1, a second link L2, a third link L3, a first auxiliary link AL1, a second auxiliary link AL2, a first rotating pair R1, a second rotating pair R2, a third rotating pair R3, a fourth rotating pair R4, a fifth rotating pair R5, a sixth rotating pair R6, and a seventh rotating pair R7. As the first link L1 rotates around the first rotating pair R1, the gripping mechanism transitions from an open state to a closed state in which the first gripping surface G1 and the second gripping surface G2 grip the gripping object OB. The second link L2 is a link that rotates relative to the first link L1 in the same direction as the rotational movement, with the second rotating pair R2 as the center of rotation. The third link L3 is a link that rotates relative to the second link L2 in the same direction as the rotational movement, with the third rotating pair R3 as the center of rotation.

Description

[Technical Field]

[0001] The present invention relates to a gripping mechanism. [Background technology]

[0002] Patent Document 1 describes a finger mechanism, which includes a first bone member, a second bone member, a third bone member, a fourth bone member, and a link mechanism. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-0043231 Summary of the Invention [Problem to be solved by the invention]

[0004] In the finger mechanism described in Patent Document 1, the movement trajectory of the gripping members is different when transitioning from a closed state in which the object is gripped to an open state in which the object is released, and when transitioning from the open state to the closed state. If the movement trajectory of the gripping members is different, it is difficult for an operator to predict the movement of the gripping members when operating the gripping mechanism while checking the positional relationship between the object and the gripping members. [Means for solving the problem]

[0005] A gripping mechanism for solving the above problem includes a fixed link, a first link having a first gripping surface, a second link, a third link having a second gripping surface, a first auxiliary link, a second auxiliary link, and a plurality of rotating pairs each having a rotation axis parallel to one another, the first rotating pair connecting a base end of the first link and the fixed link, a second rotating pair connecting a tip end of the first link and a base end of the second link, a third rotating pair connecting a tip end of the second link and a base end of the third link, a fourth rotating pair connecting a base end of the first auxiliary link and the fixed link, a fifth rotating pair connecting a tip end of the first auxiliary link and a portion of the second link that is different from the base end and the tip end, a sixth rotating pair connecting a portion of the first link between the base end and the tip end and the base end of the second auxiliary link, and a sixth rotating pair connecting a portion of the first link between the base end and the tip end and the base end of the second auxiliary link. and a seventh rotating pair connecting the tip of the third link to a portion of the third link that is different from the base end and the tip, wherein the first gripping surface is a surface that extends along a line segment connecting the first rotating pair and the second rotating pair, and the second gripping surface is a surface that extends along a line segment connecting the third rotating pair and the tip of the third link, and the gripping mechanism transitions from an open state to a closed state in which the first gripping surface and the second gripping surface can grip an object to be gripped with the first gripping surface and the second gripping surface as the first link rotates around the first rotating pair, and the second link is a link that rotates relative to the first link in the same direction as the rotational movement, with the second rotating pair as the rotational center, and the third link is a link that rotates relative to the second link in the same direction as the rotational movement, with the third rotating pair as the rotational center.

[0006] According to the above configuration, when the first link rotates around the first rotating pair, once the rotation position of the first link is determined, the position of the second rotating pair is determined. Furthermore, once the position of the fourth rotating pair and the length of the first auxiliary link are determined, the position of the fifth rotating pair is determined. Furthermore, once the positions of the second rotating pair and the fifth rotating pair are determined, the position of the third rotating pair is determined. Furthermore, once the position of the sixth rotating pair and the length of the second auxiliary link are determined, the position of the seventh rotating pair is determined.

[0007] That is, the relative positions of the second and third links with respect to the first link are uniquely determined depending on the rotational position of the first link. Therefore, the movement trajectory of the first link, second link, and third link when the gripping mechanism transitions from the open state to the closed state is the same as the movement trajectory of the first link, second link, and third link when the gripping mechanism transitions from the closed state to the open state. Therefore, this gripping mechanism makes it easy for the operator to predict the movement of each link.

[0008] In the gripping mechanism, when the first link performs the rotational movement, the magnitudes of the rotation angle θ1 of the first link, the rotation angle θ2 of the second link relative to the first link, and the rotation angle θ3 of the third link relative to the second link may satisfy the relational expression θ1<θ2<θ3.

[0009] In the gripping mechanism, an angle formed between the first gripping surface and the second gripping surface in the open state may be an obtuse angle. In the gripping mechanism, an angle formed between the first gripping surface and the second gripping surface in the closed state may be an acute angle.

[0010] The gripping mechanism may further include a cylinder having a tube and a rod that reciprocates within the tube, and a pair of rotating pairs each having a rotation axis parallel to the rotation axes of the first to seventh rotating pairs, including an eighth rotating pair that connects the tip of the rod to a portion of the first link between the first rotating pair and the second rotating pair, and a ninth rotating pair that connects the tube to the fixed link. [Effects of the Invention]

[0011] When an operator operates the gripping mechanism, the movement of the gripping member is easy to predict. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a front view showing a simplified structure of the gripping mechanism. [Figure 2]FIG. 2 is a front view showing a simplified structure of the gripping mechanism. [Figure 3] FIG. 3 is a front view showing a simplified structure of the gripping mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the gripping mechanism 10 will be described below with reference to Figs. 1 to 3. The drawings are schematic diagrams for facilitating understanding of the structure of the gripping mechanism 10, and show the components on the same plane. In the drawings, components may be enlarged or omitted. The dimensional ratios of the components in the drawings may differ from those in reality.

[0014] <Overall structure> The gripping mechanism 10 is a finger mechanism modeled after the fingers of a human hand for gripping a gripping object OB. As shown in FIG. 1, the gripping mechanism 10 includes multiple links, multiple rotating pairs connecting the respective links, and a cylinder 20 for operating the links. The links include a fixed link L0, a first link L1, a second link L2, a third link L3, a first auxiliary link AL1, and a second auxiliary link AL2. The rotating pairs include a first rotating pair R1, a second rotating pair R2, a third rotating pair R3, a fourth rotating pair R4, a fifth rotating pair R5, a sixth rotating pair R6, a seventh rotating pair R7, an eighth rotating pair R8, and a ninth rotating pair R9. The rotating pairs have rotation axes that are parallel to each other.

[0015] <permalink> In the gripping mechanism 10, the fixed link L0 corresponds to the metacarpal bones of a human finger. The fixed link L0 is connected to the first rotation pair R1, the fourth rotation pair R4, and the ninth rotation pair R9. The fixed link L0 has a triangular shape formed by connecting the rotation centers of the first rotation pair R1, the fourth rotation pair R4, and the ninth rotation pair R9 with line segments. The diagonal angle of the line segment connecting the rotation center of the first rotation pair R1 and the rotation center of the fourth rotation pair R4 is approximately 30 degrees. The diagonal angle of the line segment connecting the rotation center of the fourth rotation pair R4 and the rotation center of the ninth rotation pair R9 is approximately 20 degrees. The diagonal angle of the line segment connecting the rotation center of the ninth rotation pair R9 and the rotation center of the first rotation pair R1 is approximately 130 degrees.

[0016] <First link> In the gripping mechanism 10, the first link L1 corresponds to the proximal phalanx of a human finger. The base end of the first link L1 is connected to the first rotation pair R1. The first link L1 is rotatable relative to the fixed link L0 around the first rotation pair R1. The tip of the first link L1 is connected to the second rotation pair R2. The tip and base ends of the first link L1 are connected to the sixth rotation pair R6. The tip and base ends of the first link L1 are connected to the eighth rotation pair R8. The sixth rotation pair R6 and the eighth rotation pair R8 are located at the same position in a plane. The sixth rotation pair R6 and the eighth rotation pair R8 are located between the first rotation pair R1 and the second rotation pair R2.

[0017] <Second link> In the gripping mechanism 10, the second link L2 corresponds to the middle phalanx of a human finger. The second link L2 is connected to the second rotation pair R2, the third rotation pair R3, and the fifth rotation pair R5. The second link L2 has a triangular shape formed by connecting the rotation centers of the second rotation pair R2, the third rotation pair R3, and the fifth rotation pair R5 with line segments. The diagonal angle of the line segment connecting the rotation center of the second rotation pair R2 and the rotation center of the third rotation pair R3 is approximately 100 degrees. The diagonal angle of the line segment connecting the rotation center of the third rotation pair R3 and the rotation center of the fifth rotation pair R5 is approximately 60 degrees. The diagonal angle of the line segment connecting the rotation center of the fifth rotation pair R5 and the rotation center of the second rotation pair R2 is approximately 20 degrees.

[0018] The base end of the second link L2 is connected to the second rotating pair R2. A portion of the second link L2 that is different from the tip and base ends is connected to the fifth rotating pair R5. The acute-angled base end of the second link L2 can rotate relative to the first link L1 around the second rotating pair R2. The tip of the second link L2 is connected to the third rotating pair R3. The second link L2 rotates relative to the first link L1 in the same direction as the rotational movement of the first link L1.

[0019] <Third link> In the gripping mechanism 10, the third link L3 corresponds to the distal phalanx of a human finger. The third link L3 is connected to the third rotation pair R3 and the seventh rotation pair R7. In the following description, the point on the third link L3 that is farthest from the rotation center of the third rotation pair R3 and the rotation center of the seventh rotation pair R7 is referred to as the tip T of the third link L3. The shape of the third link L3 is triangular, with lines connecting the rotation centers of the third rotation pair R3 and the seventh rotation pair R7 to the tip T. The diagonal angle of the line segment connecting the rotation centers of the third rotation pair R3 and the seventh rotation pair R7 is approximately 20 degrees. The diagonal angle of the line segment connecting the rotation center of the seventh rotation pair R7 to the tip T is approximately 120 degrees. The diagonal angle of the line segment connecting the tip T to the rotation center of the third rotation pair R3 is approximately 40 degrees.

[0020] The base end of the third link L3 is connected to the third rotation pair R3. A portion of the third link L3 that is different from the tip and base ends is connected to the seventh rotation pair R7. The obtuse-angled base end of the third link L3 can rotate relative to the second link L2 around the third rotation pair R3. The third link L3 rotates relative to the second link L2 in the same direction as the rotational movement of the second link L2.

[0021] <First auxiliary link> The first auxiliary link AL1 supports the second link L2 in the gripping mechanism 10. The base end of the first auxiliary link AL1 is connected to the fourth rotating pair R4. The base end of the first auxiliary link AL1 is rotatable relative to the fixed link L0 around the fourth rotating pair R4. The tip of the first auxiliary link AL1 is connected to the fifth rotating pair R5. The tip of the first auxiliary link AL1 is rotatable relative to the second link L2 around the fifth rotating pair R5.

[0022] <Second auxiliary link> The second auxiliary link AL2 supports the third link L3 in the gripping mechanism 10. The base end of the second auxiliary link AL2 is connected to the sixth rotating pair R6. The base end of the second auxiliary link AL2 is rotatable relative to the first link L1 around the sixth rotating pair R6. The tip of the second auxiliary link AL2 is connected to the seventh rotating pair R7. The tip of the second auxiliary link AL2 is rotatable relative to the third link L3 around the seventh rotating pair R7.

[0023] <Cylinder> The cylinder 20 is a hydraulic cylinder. The cylinder 20 has a tube 21 having an oil chamber, and a rod 22 that reciprocates within the tube 21 by force based on the oil pressure in the oil chamber. As the rod 22 reciprocates, the amount of protrusion of the rod 22 from the tube 21 changes. The tip of the rod 22 is connected to the eighth rotating pair R8. The tip of the rod 22 is rotatable relative to the first link L1 around the eighth rotating pair R8. The base end of the tube 21 is connected to the ninth rotating pair R9. The base end of the tube 21 is rotatable relative to the fixed link L0 around the ninth rotating pair R9.

[0024] <link length> In the following description, the line segment connecting the rotation centers of any rotation pair and the length of the line segment will be referred to as Dij. Here, i and j are represented by any number from 1 to 9 that identify the rotation pair. For example, D37 represents the line segment connecting the rotation center of the third rotation pair R3 and the rotation center of the seventh rotation pair R7, or the length of the line segment. In the gripping mechanism 10, an example of the relationship in length between the line segments of each rotation pair is (D12>D16=D18>D45>D67=D87>D23>D35>D19>D14>D25>D49>D37>D26=D28).

[0025] <Angle relationship between the first link, second link and third link> In the following description, the rotation angle of the first link L1 when the first link L1 rotates around the first rotation pair R1 is referred to as the first angle θ1. The rotation angle of the second link L2 when the second link L2 rotates around the second rotation pair R2 is referred to as the second angle θ2. The rotation angle of the third link L3 when the third link L3 rotates around the third rotation pair R3 is referred to as the third angle θ3.

[0026] The magnitude of the first angle θ1 is determined by the amount of protrusion of the rod 22. Once the magnitude of the first angle θ1 is determined, the position of the second rotating pair R2 on the movement trajectory of the second rotating pair R2 is determined by the product of the magnitude of the first angle θ1 and the line segment D12. Once the position of the second rotating pair R2 on the movement trajectory is determined, the position of the third rotating pair R3 on the movement trajectory of the third rotating pair R3 is determined by the product of the magnitude of the second angle θ2 and the line segment D23. Once the position of the third rotating pair R3 on the movement trajectory is determined, the position of the tip end T on the movement trajectory of the tip end T is determined by the product of the magnitude of the third angle θ3 and the length of the line segment connecting the rotation center of the third rotating pair R3 and the tip end T.

[0027] The magnitudes of the second angle θ2 and the third angle θ3 are both determined by the amount of protrusion of the rod 22, the respective lengths of the first auxiliary link AL1 and the second auxiliary link AL2, the line segments D25 and D37, the relative positional relationship of the fifth rotation pair R5 to the second rotation pair R2, and the relative positional relationship of the seventh rotation pair R7 to the third rotation pair R3.

[0028] An example of the magnitude relationship among the first angle θ1, the second angle θ2, and the third angle θ3 when each link rotates from the open state to the closed state is (θ1<θ2<θ3). The open state and the closed state will be described later.

[0029] <Gripping surface> On the first link L1, the line segment connecting the rotation center of the first rotating pair R1 and the rotation center of the second rotating pair R2 is defined as the first imaginary straight line VL1. Of the first link L1, the surface that extends along the first imaginary straight line VL1 and faces the object to be grasped OB is defined as the first gripping surface G1. On the third link L3, the line that connects the rotation center of the third rotating pair R3 and the tip T of the third link L3 is defined as the second imaginary straight line VL2. Of the third link L3, the surface that extends along the second imaginary straight line VL2 is defined as the second gripping surface G2. The angle formed by the first gripping surface G1 and the second gripping surface G2 is defined as the specified angle SA.

[0030] On the second link L2, a line connecting the rotation center of the third rotation pair R3 and the rotation center of the fifth rotation pair R5 is defined as a third imaginary line VL3. Of the second link L2, a surface extending along the third imaginary line VL3 is defined as a third gripping surface G3. In the gripping mechanism 10, a material such as rubber is fixed to the gripping surface, which increases the friction force between the gripping object OB and the gripping surface when the gripping object OB is held.

[0031] When viewed from the rotation center of each rotation pair, the angle of 180 degrees or less at the point where the first virtual line VL1 and the second virtual line VL2 intersect is defined as the specified angle SA. In the present disclosure, the state of the gripping mechanism 10 when the specified angle SA is largest is defined as the open state of the gripping mechanism 10. The state of the gripping mechanism 10 when the specified angle SA is smallest is defined as the closed state of the gripping mechanism 10.

[0032] The gripping mechanism 10 continuously changes between an open state and a closed state in accordance with the rotational movement of the first link L1 about the first rotation pair R1. The open state of the gripping mechanism 10 is the initial state when the gripping mechanism 10 rotates, and the closed state of the gripping mechanism 10 is the final state when the gripping mechanism 10 rotates. In other words, when the state changes in accordance with the rotational movement of the gripping mechanism 10, the open state and the closed state of the gripping mechanism 10 are boundary states.

[0033] 1, when the gripping mechanism 10 is in the open state, the amount of protrusion of the rod 22 from the tube 21 is the greatest. In this state, the rod 22 pulls the second rotating pair R2 toward the tube 21 through the first link L1. The rod 22 also pulls the seventh rotating pair R7 toward the tube 21 through the second auxiliary link AL2. In this state, the specified angle SA is an obtuse angle, for example, 100 degrees.

[0034] 2, when the gripping mechanism 10 is in an intermediate state between the open state and the closed state, the amount of protrusion of the rod 22 from the tube 21 is intermediate between the maximum and minimum amounts. In this state, the rod 22 pushes the second rotating pair R2 toward the opposite side of the tube 21 via the first link L1. The rod 22 also pushes the seventh rotating pair R7 toward the opposite side of the tube 21 via the second auxiliary link AL2. In this state, the specified angle SA is smaller than 100 degrees, which is the size when the gripping mechanism 10 is in the open state.

[0035] 3, when the gripping mechanism 10 is in the closed state, the amount of protrusion of the rod 22 from the tube 21 is smallest. In this state, the rod 22 further pushes the second rotating pair R2 toward the opposite side of the tube 21 through the first link L1. The rod 22 also further pushes the seventh rotating pair R7 toward the opposite side of the tube 21 through the second auxiliary link AL2. In this state, the specified angle SA is an acute angle, for example, 30 degrees.

[0036] <Operation of this embodiment> The gripping mechanism 10 reciprocates as the rod 22 of the cylinder 20 extends or contracts. When the rod 22 extends, the first link L1, which is indirectly connected to the rod 22 by the sixth rotating pair R6, rotates around the first rotating pair R1. When the rotation of the first link L1 stops, the position of the second rotating pair R2, which is located at the tip of the first link L1, is determined.

[0037] Furthermore, once the position of the fourth rotating pair R4 connected to the fixed link L0 and the length of the first auxiliary link AL1 are determined, the position of the fifth rotating pair R5 located at the tip of the first auxiliary link AL1 is determined. Then, once the positions of the second rotating pair R2 located at the base end of the second link L2 and the fifth rotating pair R5 located at a position on the second link L2 different from the base end and the tip end are determined, the position of the third link L3 located at the tip of the second link L2 is determined.

[0038] Furthermore, once the position of the sixth rotating pair R6 connected to the first link L1 and the length of the second auxiliary link AL2 are determined, the position of the seventh rotating pair R7 located at the tip of the second auxiliary link AL2 is determined. The shape of the third link L3 is then determined by the third rotating pair R3 located at the base end of the third link L3, the seventh rotating pair R7 located at a position on the third link L3 different from the base end and the tip, and the tip portion T which is the tip of the third link L3.

[0039] <Effects of this embodiment> (1) In the gripping mechanism 10, the relative positions of the second link L2 and the third link L3 with respect to the first link L1 are uniquely determined depending on the rotational position of the first link L1. In the gripping mechanism 10, the movement trajectories of the first link L1, the second link L2, and the third link L3 when transitioning from the open state to the closed state are the same as the movement trajectories of the first link L1, the second link L2, and the third link L3 when transitioning from the closed state to the open state. Therefore, in this gripping mechanism 10, the operator can easily predict the movement of each link.

[0040] (2) In the open state of the gripping mechanism 10, the specified angle SA is an obtuse angle. Therefore, in the open state, the gripping mechanism 10 can grip a larger object to be gripped OB than when the specified angle SA is an acute angle.

[0041] (3) In the closed state of the gripping mechanism 10, the specified angle SA is an acute angle. Therefore, in the closed state, the gripping mechanism 10 can grip a larger object to be gripped OB than when the specified angle SA is an obtuse angle.

[0042] (4) The gripping mechanism 10 can swing the first link L1 around the first rotation pair R1 by the rod 22 of the cylinder 20. Therefore, the gripping mechanism 10 can change between a closed state and an open state.

[0043] (5) Rubber is fixed to the entire surfaces of the first gripping surface G1, the second gripping surface G2, and the third gripping surface G3 of the gripping mechanism 10. Therefore, the gripping mechanism 10 can prevent the gripping object OB from slipping off the first gripping surface G1, the second gripping surface G2, and the third gripping surface G3.

[0044] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0045] The first angle θ1, the second angle θ2, and the third angle θ3 do not have to satisfy the relational expression θ1<θ2<θ3. They only need to satisfy the relation that allows the gripping mechanism 10 to grip the gripping object OB. For example, the magnitudes of the first angle θ1, the second angle θ2, and the third angle θ3 may each satisfy the relational expression θ1=θ2=θ3.

[0046] In the open state, the angle formed between the first gripping surface G1 and the second gripping surface G2 does not have to be an obtuse angle. For example, the angle formed between the first gripping surface G1 and the second gripping surface G2 may be 90 degrees or less. In the closed state, the angle formed between the first gripping surface G1 and the second gripping surface G2 may be an acute angle. For example, the angle formed between the first gripping surface G1 and the second gripping surface G2 may be 90 degrees or greater.

[0047] In the gripping mechanism 10, the eighth rotating pair R8 and the sixth rotating pair R6 do not have to be provided at the same position in a plane in the first link L1. The gripping mechanism 10 does not necessarily have to include the cylinder 20. In this case, the gripping mechanism 10 may use a motor to swing the first link L1 around the first rotation pair R1 as the center of rotation.

[0048] The gripping mechanism 10 may transition to an open state or a closed state by the driving force of an actuator acting on one of the links. The cylinder 20 may be a pneumatic cylinder.

[0049] The cylinder 20 may be another linear actuator, such as an actuator including a ball screw and a motor, and the first link L1 may be oscillated by this linear actuator.

[0050] At least a portion of each link, such as the first link L1, may be made of an elastic material such as rubber. With this configuration, when grasping the graspable object OB, the link made of the elastic material elastically deforms, thereby preventing the graspable object OB from being grasped with excessive force.

[0051] At least a portion of each rotating pair may be made of an elastic material such as rubber. With this configuration, when each link grasps the object to be grasped OB, the rotating pair made of the elastic material elastically deforms, allowing the object to be grasped OB to be grasped in accordance with the shape of the object to be grasped OB.

[0052] At least a portion of each rotating pair may have a small gap between the rotating shaft and the portion supporting the rotating shaft. With this configuration, when each link grasps the object to be grasped OB, the gap at the portion where each rotating pair and link are connected becomes play, and the positional relationship of the links changes depending on the shape of the object to be grasped OB, making it possible to easily grasp the object to be grasped OB.

[0053] The third rotating pair R3 and the seventh rotating pair R7 may be spherical roller bearings. With this configuration, the tip portion T can be swung around the line segment D37 connecting the rotation center of the third rotating pair R3 and the rotation center of the seventh rotating pair R7 as the rotation axis. As a result, the position of the third link L3 can be changed according to the shape of the object to be grasped OB, making it easier to grasp the object to be grasped OB.

[0054] The relationship between the lengths of the line segments in each rotation pair does not have to be (D12>D16=D18>D45>D67=D87>D23>D35>D19>D14>D25>D49>D37>D26=D28).

[0055] The magnitude relationship between the first angle θ1, the second angle θ2, and the third angle θ3 when each link rotates from the open state to the closed state does not have to be (θ1<θ2<θ3). For example, the magnitude relationship may be θ1=θ2=θ3.

[0056] In the above embodiments, if an object is made up of multiple objects, the multiple objects may be integrated, and conversely, if an object is made up of a single object, it may be divided into multiple objects. Regardless of whether the objects are integrated or not, it is sufficient that the object of the invention can be achieved. [Explanation of symbols]

[0057] 10...Gripping mechanism 20...Cylinder 21...Tube 22...Rod L0...permalink L1...first link L2: Second link L3...Third link AL1...First auxiliary link AL2: Second auxiliary link R1...First rotation pair R2...Second rotation pair R3...3rd rotation pair R4...4th rotation pair R5...5th rotation pair R6...6th rotation pair R7...7th rotation pair R8...8th rotation pair R9…9th rotation pair T…Tip VL1: First virtual line VL2: Second virtual line G1...first gripping surface G2…Second gripping surface G3…Third gripping surface θ1…first angle θ2…Second angle θ3...Third angle SA…Specified angle OB…Gripped object

Claims

1. A cylinder having a tube and a rod that reciprocates within the tube; a fixed link, a first link having a first gripping surface, a second link, a third link having a second gripping surface, a first auxiliary link, and a second auxiliary link; a plurality of rotating pairs each having a rotation axis parallel to one another, including a first rotating pair connecting a base end of the first link and the fixed link, a second rotating pair connecting a tip end of the first link and a base end of the second link, a third rotating pair connecting a tip end of the second link and a base end of the third link, a fourth rotating pair connecting a base end of the first auxiliary link and the fixed link, a fifth rotating pair connecting a tip end of the first auxiliary link and a portion of the second link that is different from the base end and the tip end, a sixth rotating pair connecting a portion of the first link between the base end and the tip end and the base end of the second auxiliary link, and a seventh rotating pair connecting a tip end of the second auxiliary link and a portion of the third link that is different from the base end and the tip end; a pair of rotating pairs each having a rotation axis parallel to the rotation axes of the first to seventh rotating pairs, including an eighth rotating pair connecting a tip end of the rod and a portion of the first link between the first rotating pair and the second rotating pair, and a ninth rotating pair connecting the tube and the fixed link; the first gripping surface is a surface extending along a line segment connecting the first rotating pair and the second rotating pair, and the second gripping surface is a surface extending along a line segment connecting the third rotating pair and the tip of the third link, a gripping mechanism that transitions from an open state to a closed state in which a gripping object can be gripped by the first gripping surface and the second gripping surface in response to a rotational movement of the first link about the first rotation pair, the second link is a link that rotates relative to the first link in the same direction as the rotational movement, with the second rotation pair as a rotation center, the third link is a link that rotates relative to the second link in the same direction as the rotational movement, with the third rotation pair as a rotation center; Gripping mechanism.

2. when the first link performs the rotational movement from the open state to the closed state, the magnitudes of a rotation angle θ1 of the first link, a rotation angle θ2 of the second link relative to the first link, and a rotation angle θ3 of the third link relative to the second link satisfy a relational expression of θ1<θ2<θ3. The gripping mechanism of claim 1 .

3. In the open state, the angle formed between the first gripping surface and the second gripping surface is an obtuse angle. The gripping mechanism of claim 1 .

4. In the closed state, the angle formed between the first gripping surface and the second gripping surface is an acute angle. The gripping mechanism of claim 1 .

Images