JP6855064B2 - Joint mechanism - Google Patents

Description

The present invention relates to a joint mechanism with rotational pairing.

Conventional rotary pairs consisting of shafts and bearings have been widely used in mechanical structures such as link mechanisms. Such rotational pairs of shafts and bearings are easily destroyed because bending stress and torsional stress due to external force are concentrated on the shaft at one point, and the mobility is significantly impaired due to deterioration of restraint due to rust and distortion. was there. In the conventional rotary pair, in order to avoid destruction due to an external force, high-precision processing based on the bearing is required, and the number of structural materials related to the shaft and the bearing increases. Therefore, there is a problem that the rotational pair of the shaft and the bearing becomes heavy and has high rigidity. To solve this problem, Patent Document 1 proposes a flexible musculoskeletal arm using a ball-jointed doll.

Japanese Unexamined Patent Publication No. 2011-121163 (published on June 23, 2011)

AC Etoundi, R Vaidyanathan, and SC Burgess. “A bio-inspired condylar hinge joint for mobile robots.” Inteligent Robots and Systems (IROS), 2011 IEEE / RSJ International Conference on. IEEE, 2011.

However, the ball-jointed doll described in Patent Document 1 has a problem that it is vulnerable to deterioration due to rust and distortion and also increases in weight, like a conventional joint composed of a shaft and a bearing.

A joint that approximates a human knee joint to a link mechanism (Non-Patent Document 1) has characteristics and durability suitable for a walking robot, but is large in size, heavy in weight, and complicated in design and manufacturing procedures. There is a problem that it is difficult. Further, due to the structure of the joint, there is a problem that the rotational movement of the joint may be disturbed due to the occurrence of slippage in the rolling joint.

One aspect of the present invention is to realize a joint mechanism that does not require a shaft and a bearing, is compact and lightweight, and is easy to manufacture.

In order to solve the above problems, the joint mechanism according to one aspect of the present invention includes a pair of first side planes arranged in parallel with each other and at least a part of one end formed in a curved shape, and the pair of first side planes. To roll on the first member having the first rolling surface formed between the first side planes, the pair of second side planes corresponding to the pair of first side planes, and the first rolling surface. A second member having a second rolling surface formed between the pair of second side planes, and the first side plane and the second side in order to press the second rolling surface against the first rolling surface. A pair of side wire arranged so as to straddle a flat surface, and the first rolling surface and the second rolling surface in order to prevent slippage between the first rolling surface and the second rolling surface. It is characterized by having a pair of intersecting wires arranged so as to intersect each other along the line.

According to this feature, the pair of side wires presses the second rolling surface against the first rolling surface, and the pair of intersecting wires prevents slippage between the first rolling surface and the second rolling surface. Therefore, a rotating pair without a shaft and a bearing rotates by a rolling motion, and a compact and lightweight joint mechanism that is easy to manufacture can be realized.

In the joint mechanism according to one aspect of the present invention, it is preferable that one end of the pair of first side planes is formed in an arc shape.

According to the above configuration, the second rolling surface rolls on the first rolling surface, so that the second member can rotate 360 degrees around the first member.

In the joint mechanism according to one aspect of the present invention, the first through hole penetrating the pair of first side planes is formed in the first member, and the second through hole penetrating the pair of second side planes is said. One of the pair of side wires formed in the second member is connected to the other of the pair of side wires through the first through hole, and the other of the pair of side wires is connected through the second through hole. It is preferable to be connected with.

According to the above configuration, the pair of side wires can be simply configured with one wire.

In the joint mechanism according to one aspect of the present invention, a part of one end of the pair of first side planes has an arc shape, and the other part of the other end is around the first member of the second member. It is preferable to have a rotation range limiting shape that limits the rotation range.

According to the above configuration, the rotation range limiting shape acts as a stopper for the rotation of the first member, and the movable range of the joint mechanism can be limited.

In the joint mechanism according to one aspect of the present invention, it is preferable that the rotation range limiting shape includes a first straight line shape in contact with the arc shape and a second straight line shape orthogonal to the first straight line shape.

According to the above configuration, the rotation range limited shape can be realized by a simple configuration.

In the joint mechanism according to one aspect of the present invention, a part of one end of the pair of first side planes has an arc shape, and the other part of the other end has the second member in a first state to a second state. It is preferable to have a jumping shape for jumping to.

According to the above configuration, the characteristic of releasing energy at once in the process of jumping from the energy storage state to the energy release state can be obtained.

In the joint mechanism according to one aspect of the present invention, it is preferable that the jump shape includes a first straight line shape connected to the arc shape and a second straight line shape obliquely intersecting the first straight line shape.

According to the above configuration, the jump shape can be realized by a simple configuration.

In the joint mechanism according to one aspect of the present invention, it is preferable that a tension regulator for adjusting the tension of the side wire is provided on at least one of the first side plane and the second side plane.

According to the above configuration, by adjusting the initial tension of the side wire with the tension regulator, it is possible to finely adjust the mechanical characteristics such as the joint rigidity of the joint mechanism.

According to one aspect of the present invention, it is possible to realize a joint mechanism that is compact, lightweight, and easy to manufacture.

(A) is a perspective view for explaining a rolling surface of a link member provided in the joint mechanism according to the first embodiment, and (b) is a perspective view for explaining a side wire provided in the joint mechanism. (C) is a perspective view for explaining another side wire provided in the joint mechanism, and (d) is a perspective view for explaining an intersecting wire provided in the joint mechanism. , (E) are perspective views for explaining other crossing wires provided in the joint mechanism. (A) to (c) are side views showing the operation of the joint mechanism. (A) to (c) are side views for explaining the range of motion of the joint mechanism. (A) and (b) are perspective views of the joint mechanism according to the second embodiment. (A) is a side view of the joint mechanism according to the first embodiment, and (b) to (d) are side views showing the operation of the joint mechanism according to the third embodiment. (A) and (b) are side views showing the operation of the joint mechanism according to the fourth embodiment. It is a figure which shows the application example of the joint mechanism which concerns on Embodiment 5. It is a figure which shows the other application example of the joint mechanism which concerns on Embodiment 5.

Hereinafter, embodiments of the present invention will be described in detail.

(Embodiment 1)
FIG. 1A is a perspective view for explaining a rolling surface 3a of the link member 2a provided in the joint mechanism 1 according to the first embodiment, and FIG. 1B is a perspective view showing a side wire 5 provided in the joint mechanism 1. It is a perspective view for demonstrating, (c) is a perspective view for demonstrating the side wire 6 provided in the joint mechanism 1, and (d) is the crossing wire 7 provided in the joint mechanism 1. (E) is a perspective view for explaining the crossing wire 8 provided in the joint mechanism 1. 2 (a) to 2 (c) are side views showing the operation of the joint mechanism 1.

The joint mechanism 1 includes a link member 2a (first member). The link member 2a is a rolling surface 3a (first) formed between a pair of side planes 4a (first side plane) arranged parallel to each other and having one end formed in a semicircular shape and a pair of side planes 4a. It has a rolling surface). A through hole 9a (first through hole) penetrating the pair of side planes 4a is formed at one end of the link member 2a.

The joint mechanism 1 is provided with a link member 2b (second member). The link member 2b is configured in the same manner as the link member 2a. That is, the link member 2b is a rolling surface 3b (2) formed between a pair of side planes 4b (second side plane) arranged parallel to each other and one end formed in a semicircular shape, and a pair of side planes 4b. It has a second rolling surface). A through hole 9b (second through hole) penetrating the pair of side planes 4b is formed at one end of the link member 2b.

The link member 2a is arranged so that the rolling surface 3a faces the rolling surface 3b of the link member 2b and the rolling surface 3a rolls on the rolling surface 3b.

The joint mechanism 1 includes a pair of side wires 5 and 6. The side wire 5 is arranged so as to straddle one of the pair of side planes 4a and one of the pair of side planes 4b in order to press the rolling surface 3b against the rolling surface 3a. The side wire 6 is arranged so as to straddle the other of the pair of side planes 4a and the other of the pair of side planes 4b in order to press the rolling surface 3b against the rolling surface 3a.

One end of the side surface wire 5 can be fixed to one of the side planes 4a by a known method such as a screw, and the other end of the side surface wire 5 can be fixed to one of the side planes 4b by a known method such as a screw. .. One end of the side surface wire 6 can be fixed to the other side plane 4a by a known method, and the other end of the side surface wire 6 can be fixed to the other side surface 4b by a known method.

The side wire 5 and the side wire 6 are composed of one wire so that the side wire 5 is connected to the other side wire 6 through the through hole 9a and is connected to the side wire 6 through the through hole 9b. You may.

The joint mechanism 1 is provided with a pair of intersecting wires 7 and 8. As shown in FIGS. 1 (d) and 1 (e), the intersecting wires 7 and 8 are arranged so as to intersect each other along the rolling surface 3a and the rolling surface 3b. The intersecting wires 7 and 8 prevent slippage between the rolling surface 3a and the rolling surface 3b during the operation of the joint mechanism 1.

The materials of the side wires 5 and 6 and the cross wires 7 and 8 are preferably materials having high strength and non-stretchability, and examples thereof include UHPE (Ultra High Molecular Weight Polyethylene) fibers.

The joint mechanism 1 configured in this way operates as follows.

First, as shown in FIG. 2A, from the state where the link members 2a and 2b are arranged in a straight line, the rolling surface 3a rolls on the rolling surface 3b without sliding, so that the link member 2a rotates clockwise. The state shown in FIG. 2B, in which the link member 2a is bent perpendicularly to the link member 2b, after the state shown in FIG. 2B, which is rotated in the direction of the link member 2b and bent diagonally with respect to the link member 2b. Become.

At this time, the side wires 5 and 6 function to maintain contact between the rolling surfaces 3a and 3b and restrain the movement of the link members 2a and 2b in directions other than the bending direction. Further, the intersecting wires 7 and 8 function to prevent the rolling surfaces 3a and 3b from slipping each other.

The present embodiment is a rotation mechanism composed of rolling surfaces 3a and 3b corresponding to cartilage in a human knee joint, side wires 5.6 corresponding to ligaments in the knee joint, and crossing wires 7.8. The novelty of this embodiment is that the shaft is not used to restrain the joint, and instead of the shaft, a plurality of wires (side wires 5.6, crossing wires 7 and so on) that imitate the ligaments in the human knee joint are used. 8) is used.

3A to 3C are side views for explaining the range of motion of the joint mechanism 1. The link member 2a can be rotated 180 degrees clockwise from the state shown in FIG. 3B to the state shown in FIG. 3C by rolling the rolling surface 3a on the rolling surface 3b. Then, the state shown in FIG. 3B can be rotated 180 degrees counterclockwise from the state shown in FIG. 3A to the state shown in FIG. 3A. The joint mechanism 1 has a wide range of motion of 360 degrees because the rotation center of the bending motion of the link member 2a moves along the rolling surface 3b.

Since the conventional joint mechanism consisting of a shaft and a bearing is precisely configured, there is a problem that if an external force acts in the bending direction of the shaft and the shaft bends and even a slight deviation from the bearing, it will not function. There is.

On the other hand, since the joint mechanism 1 of the present embodiment is configured to be ambiguous to some extent, the wires (side wires 5.6 and intersecting wires 7.8) are pulled even if an external force acts in the bending direction. Due to the elongation based on the above, the link members 2a and 2b are allowed to be displaced in a direction other than the bending operation direction. Therefore, the joint mechanism 1 is tougher against an external force than the conventional joint mechanism including the shaft and the bearing. The joint mechanism 1 is softer in its operation than the conventional joint mechanism, and is particularly tough against impact force as compared with the conventional joint mechanism having the same mass.

According to this embodiment, since no shaft or bearing is used, precise machining is not required, and the manufacturing cost can be reduced. Since no shaft or bearing is used, the weight of the joint mechanism can be reduced by reducing the number of structural materials related to the joint.

Further, since the wire does not need to consider buckling, it is strong against a load, and by giving the joint mechanism 1 of the present embodiment appropriate flexibility by the minute elongation of the wire, the impact force acting on the joint mechanism 1 can be applied. Can be absorbed.

Further, as shown in FIG. 3, the movable range is widened as compared with the conventional joint mechanism, and the folding operation that rotates by about 180 degrees becomes possible.

Further, by improving the shapes of the rolling surfaces 3a and 3b as described later, the flexibility and rigidity of the joint mechanism 1 can be adjusted.

Since the joint mechanism 1 of the present embodiment is modularized as a single mechanical element, it can be easily replaced with a rotational pair even in a conventional mechanical structure.

Due to the above properties, the present embodiment can be widely applied to a conventional mechanical structure, and is innovative in that it is superior in impact resistance and light weight as compared with a conventional joint structure using a shaft and a bearing. is there.

The joint mechanism 1 includes two rolling surfaces 3a and 3b that restrain the rotation directions of the link members 2a and 2b, and four wires (side wire 5.6 and crossing wires 7.8) that restrain the rolling surfaces 3a and 3b. ) Is a rotation mechanism. The two side wire 5 and 6 extending from the center of the semicircle at one end of the link member 2a and the center of the semicircle at one end of the link member 2b press the rolling surface 3a against the rolling surface 3b while pressing the link member 2a. It plays a role of supporting an undesired bending stress in a plane perpendicular to the side planes 4a and 4b of 2b and an undesired torsional stress in the axial direction of the link members 2a and 2b. The intersecting wires 7 and 8 arranged so as to intersect along the rolling surfaces 3a and 3b play a role of supporting unwanted bending stress while eliminating slippage between the rolling surfaces 3a and 3b.

When the rolling surfaces 3a and 3b are formed by a semi-cylindrical shape without distortion, the distance between the centers between the two semicircles forming the two rolling surfaces 3a and 3b and the circumference of the semicircle are geometric. Does not change scientifically. Therefore, while the link member 2a of the joint mechanism 1 shown in FIGS. 2 (a) to 2 (c) is rotating with respect to the link member 2b in the bending direction, the wires (side wires 5.6 and intersecting). The wires 7 and 8) do not stretch, and smooth rolling rotation of the rolling surface 3a with respect to the rolling surface 3b occurs. However, if an attempt is made to rotate in a direction other than the above direction, the wire is stretched. Therefore, the rigidity of the wire can restrain an undesired rotational movement in a direction other than the above direction.

Unlike the conventional rotary pair, the joint mechanism 1 of the present embodiment does not use a shaft and a bearing. Therefore, precision machining is not required, and the weight of the joint mechanism can be reduced by reducing the structural materials related to the shaft and the bearing. Further, due to the flexibility of the wire, the joint mechanism 1 of the present embodiment has excellent load resistance and impact resistance. The joint mechanism 1 of the present embodiment is modularized as a single mechanical element. Therefore, it is possible to replace the conventional rotating kinematic pair in the mechanical structure.

From the above properties, the joint mechanism 1 of the present embodiment can be widely applied to a conventional mechanical structure, does not require precision processing, and is lightweight, so that cost reduction can be expected.

It can be applied to ultra-lightweight structures that were difficult to realize with conventional mechanical structures, and machines with unexpected collisions and contact with the outside world, which were difficult to realize in the past from the viewpoint of danger and the like. Can be newly applied to.

Due to its light weight, the joint mechanism 1 of the present embodiment can be applied to applications requiring an ultra-lightweight mechanism such as a deployable space structure and a robot arm mounted on a drone. In addition, due to its inertia and impact resistance, it can be applied to mechanical structures that operate in a real-world environment, such as rough terrain traveling robots and medical / nursing robots that carry the risk of unexpected collisions with the outside world and people.

(Embodiment 2)
4 (a) and 4 (b) are perspective views of the joint mechanism 1A according to the second embodiment. The same components as those described above are designated by the same reference numerals. The detailed description of these components will not be repeated.

The joint mechanism 1A includes a tension regulator 10. The tension regulator 10 is arranged on one of the side planes 4a of the link member 2a and one of the side planes 4b of the link member 2b in order to adjust the tension of the side wire 5. Then, the tension adjuster 10 for adjusting the tension of the side wire 6 is arranged on the other side plane 4a of the link member 2a and the other side plane 4b of the link member 2b.

As shown in FIG. 4A, when the initial tension of the side wire 5 and 6 is set small by the tension regulator 10, the degree of freedom of twisting in the direction indicated by the arrow 21 of the joint mechanism 1A increases. As shown in FIG. 4B, when the initial tension of the side wires 5 and 6 is set large by the tension regulator 10, the degree of freedom of twisting in the direction indicated by the arrow 22 of the joint mechanism 1A becomes small. As described above, in addition to the effect of the first embodiment, according to the second embodiment, by adjusting the initial tension of the side wires 5 and 6 with the tension regulator 10, mechanical characteristics such as joint rigidity of the joint mechanism 1A are obtained. Can be fine-tuned. For example, when precise rotation operation is required, a strong tension may be applied by the tension regulator 10, and when flexibility for absorbing impact force or the like is required, a weak tension may be applied by the tension regulator 10. ..

(Embodiment 3)
5A is a side view of the joint mechanism 1 according to the first embodiment, and FIGS. 5B to 5D are side views showing the operation of the joint mechanism 1B according to the third embodiment. The same components as those described above are designated by the same reference numerals. The detailed description of these components will not be repeated.

The joint mechanism 1B includes link members 15a and 15b. At the tip of the link member 15a, an arcuate surface 11a and a jump-shaped surface 12a connected to the arcuate surface 11a are formed. The jump-shaped surface 12a includes a first linear surface 13a connected to the arc surface 11a and a second linear surface 14a obliquely intersecting the first linear surface 13a. At the tip of the link member 15b, an arcuate surface 11b and a jump-shaped surface 12b connected to the arcuate surface 11b are formed. The jump-shaped surface 12b includes a first linear surface 13b connected to the arc surface 11b and a second linear surface 14b obliquely intersecting the first linear surface 13b.

The joint mechanism 1B configured in this way operates as follows.

First, as shown in FIG. 5 (b), from the state where the link members 15a and 15b are arranged in a straight line, the link member 15a rotates clockwise with respect to the link member 15b, and FIG. As shown in the above, the first linear shape surface 13a is in contact with the first linear shape surface 13b and shifts to an energy storage state (first state) in which energy is stored. Then, the link member 15a further rotates clockwise with respect to the link member 15b, and the first linear shape surface 13a separates from the first linear shape surface 13b, and as shown in FIG. 5D, the second linear shape is formed. The surface 14a approaches the second linearly shaped surface 14b and shifts to an energy release state (second state) in which energy is released at once. This phenomenon is called a jumping buckling phenomenon.

As described above, the joint mechanism 1B according to the present embodiment realizes desired mechanical characteristics by devising the shape of the rolling surface. That is, a small chevron shape is formed by the first linear shape surface 13a and the second straight shape surface 14a, and a small chevron shape is formed by the first straight shape surface 13b and the second straight shape surface 14b, and the link is formed. The curvatures of the rolling surface of the member 2a and the rolling surface of the link member 2b are partially changed. As a result, energy is accumulated from the state shown in FIG. 5 (b) to the energy storage state shown in FIG. 5 (c), and the energy release state shown in FIG. 5 (d) is changed from the energy storage state shown in FIG. 5 (c). In the process of shifting to, the characteristic of releasing energy at once is obtained. Such a joint mechanism 1B can be applied to, for example, a jumping robot that requires a large instantaneous output. The production and fine adjustment of such rolling surfaces (arc surfaces 11a / 11b, jumping shape surfaces 12a / 12b) can be easily realized by using a laminated 3D printer.

(Embodiment 4)
6 (a) and 6 (b) are side views showing the operation of the joint mechanism 1C according to the fourth embodiment. The same components as those described above are designated by the same reference numerals. The detailed description of these components will not be repeated.

The joint mechanism 1C includes link members 20a and 20b. At the tip of the link member 20a, an arc surface 19a and a rotation range limited shape surface 16a connected to the arc surface 19a are formed. The rotation range limited shape surface 16a includes a first straight line shape surface 17a connected to the arc surface 19a and a second straight line shape surface 18a orthogonal to the first straight line shape surface 17a. At the tip of the link member 20b, an arc surface 19b and a rotation range limited shape surface 16b connected to the arc surface 19b are formed. The rotation range limited shape surface 16b includes a first straight line shape surface 17b connected to the arc surface 19b and a second straight line shape surface 18b orthogonal to the first straight line shape surface 17b.

The joint mechanism 1B configured in this way operates as follows.

First, from the state shown in FIG. 6B in which the arcuate surfaces 19a and 19b are in contact with each other and the rotation range limited shape surfaces 16a and 16b are separated from each other, the arcuate surface 19a rolls on the arcuate surface 19b to link. The member 20a rotates counterclockwise with respect to the link member 20b, and the state shifts to the state shown in FIG. 6A in which the link members 20a and 20b are located on a straight line. Then, further counterclockwise rotation of the link member 20a is blocked by the shapes of the rotation range limited shape surfaces 16a and 16b.

As described above, the joint mechanism 1C according to the fourth embodiment realizes desired mechanical characteristics by devising the shape of the rolling surface as in the third embodiment. That is, a larger chevron shape is formed by the first linear shape surface 17a and the second straight shape surface 18a, and a larger chevron shape is formed by the first straight shape surface 17b and the second straight shape surface 18b to form a link. The curvatures of the rolling surface of the member 2a and the rolling surface of the link member 2b are partially changed. As a result, the rotation range limited shape surfaces 16a and 16b act as stoppers against the counterclockwise rotation of the link member 20a, and the movable range of the joint mechanism 1C can be limited.

(Embodiment 5)
FIG. 7 is a diagram showing an application example of the joint mechanism according to the fifth embodiment. The joint mechanisms 1, 1A, 1B, and 1C described in the first to fourth embodiments can be mounted on the joint portion A of the power assist suit 23 to be attached to the human body, for example.

FIG. 8 is a diagram showing another application example of the joint mechanism according to the fifth embodiment. The joint mechanisms 1, 1A, 1B, and 1C can be mounted on the joint portion B of the quadruped walking robot 24 that collides with the human body and the environment.

Further, since the joint mechanisms 1, 1A, 1B, and 1C have excellent ultralightness, impact resistance, and safety (impact resistance), for example, they are lightweight and portable for tents, temporary housing, and the like. It can be mounted on deployable structures, space structures such as antennas, mechanisms mounted on drones, and robots that come into contact with the environment or the human body.

Since it can be manufactured without using metal parts, metal parts such as peripheral equipment related to medical MRI (Magnetic Resonance Imaging) and equipment with a risk of chemical erosion. The joint mechanisms 1, 1A, 1B, and 1C can be mounted on a device whose use is restricted.

Since it has geometric characteristics similar to the joint structure of the human body whose rotation center changes depending on the joint angle, the joint mechanisms 1, 1A, 1B, and 1C can be mounted on the orthosis to be attached to the human body.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

1 Joint mechanism 2a Link member (first member)
2b link member (second member)
3a Rolling surface (first rolling surface)
3b Rolling surface (second rolling surface)
4a side plane (first side plane)
4b side plane (second side plane)
5, 6 Side wire 7, 8 Crossing wire 9a Through hole (first through hole)
9b through hole (second through hole)
10 Tension regulators 11a, 11b Arc surface 12a, 12b Jump shape 13a, 13b First straight shape surface (jump shape, first straight shape)
14a, 14b 2nd straight line shape surface (jump shape, 2nd straight line shape)
15a link member (first member)
15b link member (second member)
16a, 16b Rotation range limited shape 17a, 17b First straight line shape (rotation range limited shape)
18a, 18b 2nd straight line shape (rotation range limited shape)
19a, 19b Arc surface 20a Link member (first member)
20b link member (second member)

Claims (8)

A first member having a pair of first side planes arranged parallel to each other and having at least a part of one end formed in a curved shape, and a first rolling surface formed between the pair of first side planes. ,
A second having a pair of second side planes corresponding to the pair of first side planes and a second rolling surface formed between the pair of second side planes for rolling on the first rolling surface. 2 members and
A pair of side wires arranged so as to straddle the first side plane and the second side plane in order to press the second rolling surface against the first rolling surface.
With a pair of intersecting wires arranged so as to intersect each other along the first rolling surface and the second rolling surface in order to prevent slippage between the first rolling surface and the second rolling surface. A joint mechanism characterized by being equipped with. The joint mechanism according to claim 1, wherein one end of the pair of first side planes is formed in an arc shape. A first through hole penetrating the pair of first side planes is formed in the first member.
A second through hole penetrating the pair of second side planes is formed in the second member.
Claim 1 in which one of the pair of side wires is connected to the other of the pair of side wires through the first through hole and is connected to the other of the pair of side wires through the second through hole. The joint mechanism described in. A part of one end of the pair of first side planes has an arc shape, and the other part of the one end has a rotation range limiting shape that limits the rotation range of the second member around the first member. The joint mechanism according to claim 1. The joint mechanism according to claim 4, wherein the rotation range limited shape includes a first straight line shape in contact with the arc shape and a second straight line shape orthogonal to the first straight line shape. A claim in which a part of one end of the pair of first side planes has an arc shape, and the other part of the other end has a jump shape for the second member to jump from the first state to the second state. Item 1. The joint mechanism according to item 1. The joint mechanism according to claim 6, wherein the jump shape includes a first straight line shape connected to the arc shape and a second straight line shape diagonally intersecting the first straight line shape. The joint mechanism according to claim 1, wherein a tension regulator for adjusting the tension of the side wire is provided on at least one of the first side plane and the second side plane.

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