Joint device

Abstract

The present invention is a joint device attached to a robot arm, comprising: a first main body having a rotating shaft; a second body disposed along the rotation axis and rotatable with respect to the first body; one end of the limiting part is additionally arranged on the rotating shaft, the other end of the limiting part is arranged between the first main body and the second main body, and the limiting part can rotate with the rotating shaft as the center.

Description

Technical Field

[0001] The invention relates to a joint device installed on a robot arm. Background Art

[0002] Joint devices that rotate a pivoted component are well known. The pivoted component rotates around the rotation axis of the joint device.

[0003] The joint device is used, for example, to drive the joint of a robot. In this case, the robot arm is equivalent to the pivoted member. The joint device sometimes has a limiting mechanism that physically limits the pivoting range of the pivoted member. Summary of the invention

[0004] Technical issues

[0005] The present invention aims to provide a joint device with an expanded rotatable range.

[0006] Technical Solution

[0007] One aspect of the present invention provides a joint device, comprising: a first body, the first body having a rotation axis; a second body, the second body is arranged along the rotation axis and can rotate relative to the first body; and a limiting portion, one end of the limiting portion is attached to the rotation axis, and the other end is arranged between the first body and the second body, and can rotate around the rotation axis.

[0008] One aspect of the present invention provides a joint device, wherein the second body comprises: a protruding portion, the protruding portion is arranged adjacent to one end of the limiting portion to limit the rotation of the limiting portion;

[0009] When the second body rotates in one direction, one end of the limiting portion is supported on one side of the protruding portion, and the other end is supported on the first protrusion.

[0010] When the second body rotates in another direction, the one end is supported on the other side of the protruding portion, and the other end is supported on the second protrusion.

[0011] Effects of the Invention

[0012] The joint device of one embodiment of the present invention can expand the rotatable range. The limiter disposed between the first body and the second body rotates along the rotation axis, so the rotatable range between the first body and the second body can be set to exceed 360 degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a three-dimensional view showing a joint device according to an embodiment of the present invention.

[0014] Figure 2 for Figure 1 A stereoscopic view of the joint device in a first position.

[0015] Figure 3 for Figure 1 A stereoscopic view of the joint device in a second position.

[0016] Figure 4 for Figure 2 Top view of the .

[0017] Figure 5 for Figure 3 Top view of the .

[0018] Figure 6 To show Figure 1 A side view of the articular arrangement.

[0019] Figure 7 To show Figure 1 FIG. 1 is a diagram of another embodiment of a joint device.

[0020] Best Mode for Carrying Out the Invention

[0021] One aspect of the present invention provides a joint device, comprising: a first body, the first body having a rotation axis; a second body, the second body is arranged along the rotation axis and can rotate relative to the first body; and a limiting portion, one end of the limiting portion is attached to the rotation axis, and the other end is arranged between the first body and the second body, and can rotate around the rotation axis.

[0022] In addition, the device may further include a driving motor, wherein the driving motor is disposed on at least one of the first body and the second body to rotate the first body or the second body.

[0023] In addition, the first body may include: a first protrusion that contacts the other end of the stopper to limit the rotation angle; and a second protrusion that is spaced apart from the first protrusion and contacts the other end of the stopper to limit the rotation angle.

[0024] In addition, the second body may include: a protrusion, which is arranged adjacent to one end of the limiting portion to limit the rotation of the limiting portion; wherein, when the second body rotates in one direction, the one end of the limiting portion can be supported on one side of the protrusion, and the other end can be supported on the first protrusion, and when the second body rotates in the other direction, the one end can be supported on the other side of the protrusion, and the other end can be supported on the second protrusion.

[0025] Other aspects, features, and advantages in addition to the foregoing will become apparent from the following drawings, claims, and summary of the invention. DETAILED DESCRIPTION

[0026] The following embodiments are described in detail with reference to the accompanying drawings. When describing with reference to the accompanying drawings, the same or corresponding components are given the same figure numbers, and repeated descriptions thereof are omitted.

[0027] The embodiments of the present invention can be subjected to various changes, and specific embodiments will be exemplarily shown in the drawings and described in detail in the text. Figure 1 The effects and features of the embodiments of the present invention and the methods for achieving the same will be clear from the detailed description. However, the embodiments of the present invention are not limited to the embodiments disclosed below, and can be embodied in various forms.

[0028] In the following embodiments, the terms "first" and "second" are not intended to be limiting but are used to distinguish one constituent element from other constituent elements.

[0029] In the following embodiments, an expression in the singular includes an expression in the plural as long as the context does not clearly indicate otherwise.

[0030] In the following embodiments, terms such as including or having mean that the features or constituent elements described in the specification are present, and do not preclude the possibility of adding one or more other features or constituent elements.

[0031] In the following embodiments, when referring to a unit, region, constituent element or the like as being above or on top of other parts, it includes not only the case where the unit, region, constituent element or the like is immediately above the other parts, but also the case where other units, regions, constituent elements or the like are present in between.

[0032] In the following embodiments, as long as the context does not clearly indicate otherwise, terms such as connection or coupling do not mean that two components must be directly and / or fixedly connected or coupled, and do not exclude the presence of other components between the two components.

[0033] This means that the features or constituent elements described in the specification exist, and does not preclude the possibility of adding one or more other features or constituent elements.

[0034] In the drawings, the sizes of the components may be exaggerated or reduced for the convenience of description. For example, the sizes and thicknesses of the components shown in the drawings are arbitrarily shown for the convenience of description, and thus the following embodiments are not necessarily limited to the contents shown.

[0035] An embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0036] Figure 1 FIG. 1 is a perspective view showing a joint device 100 according to an embodiment of the present invention.

[0037] Reference Figure 1 , the joint device 100 can be defined as a device for adjusting the rotation angle of two bodies.

[0038] The joint device 100 is used to limit the rotation range of two structures that rotate relative to each other, and can be applied to various industrial structures or medical structures, etc. For ease of description, the following description focuses on an embodiment of limiting the rotation angle between a structure with a first body 110 and a structure with a second body 120.

[0039] Figure 2 for Figure 1 A three-dimensional diagram of the joint device in a first position, Figure 3 for Figure 1 A perspective view of the joint device in a second position, Figure 4 for Figure 2 A top view of Figure 5 for Figure 3 A top view of Figure 6 To show Figure 1 A side view of the articular arrangement.

[0040] Reference Figures 2 to 6 The joint device 100 can adjust the rotation range of the first body 110 and the second body 120. The joint device 100 may include a first body 110, a second body 120 and a limiting portion 130.

[0041] The first body 110 may have a rotation axis AX. The first body 110 may have the same rotation axis AX as the second body 120 and rotate around the rotation axis AX.

[0042] As an embodiment, the first body 110 may include a circular plate shape having more than two height staggered sections and formed in a stepped manner. For example, the diameter of the surface 111 configured at the upper portion of the first body 110 may be formed to be smaller than the diameter of the body configured at the lower portion. Therefore, the first body 110 can minimize the area of ​​contact with the second body 120 to prevent interference between structures during pivoting operation. In addition, a connection portion with a housing equipped with a drive portion may be formed. However, the shape of the first body 110 is not limited thereto and may be configured in various shapes according to the purpose of use.

[0043] The first body 110 may have at least one protrusion for limiting the rotation of the limiting portion 130 .

[0044] The first body 110 may be provided with a protrusion on a surface 111 facing the second body 120 .

[0045] The protrusion configured on the first body 110 is fixed on the surface 111, and there is no particular limitation. For example, the protrusion configured on the first body 110 can be one, or a convex-concave structure including a plurality of protrusions.

[0046] However, for the convenience of description, in the present embodiment, a case where the first body 110 includes a plurality of protrusions is described.

[0047] As an example, the first body 110 may include a first protrusion 112, which contacts the other end of the stopper 130 to limit the rotation angle. In addition, the first body 110 may include a second protrusion 113, which is separated from the first protrusion 112 and contacts the other end of the stopper 130 to limit the rotation angle.

[0048] The first protrusion 112 and the second protrusion 113 may be configured to protrude from the surface 111. The first protrusion 112 and the second protrusion 113 may have a predetermined height T.

[0049] In addition, the first protrusion 112 may extend from the surface 111 along the radial direction of the rotation axis AX. The second protrusion 113 may also extend from the surface 111 along the radial direction of the rotation axis AX. The first protrusion 112 and the second protrusion 113 may be arranged as close to the rotation axis AX as possible to ensure a rotation space for the first body 110.

[0050] The first protrusion 112 and the second protrusion 113 may be set to the same height as each other, or may be set to different heights. Alternatively, the first protrusion 112 and the second protrusion 113 may be composed of a staggered structure with a hanging edge so as to be placed on the limiting portion 130. However, for ease of description, the following description is centered on an embodiment in which the first protrusion 112 and the second protrusion 113 are set at the same height.

[0051] The first protrusion 112 and the second protrusion 113 may be shaped corresponding to the shape of the stopper 130 so as to limit the rotation of the stopper 130. In addition, the first body 110 is shown in the drawings to have only the first protrusion 112 and the second protrusion 113, but a plurality of protrusions may be provided according to the purpose.

[0052] The first protrusion 112 and the second protrusion 113 are disposed on a rotation path of the limiting portion 130 , and can limit the rotation of the limiting portion 130 .

[0053] The extension lines of the first protrusion 112 and the second protrusion 113 may be arranged apart from the rotation axis AX. Figure 4 The extension lines of the first protrusion 112 and the second protrusion 113 can be arranged at a predetermined distance from the rotation axis to expand the rotatable angle between the first body 110 and the second body 120.

[0054] A first drive motor 10 may be disposed on one side of the first body 110, and the driving force of the first drive motor 10 may be transmitted to the rotation axis AX, so that the second body 120 may rotate relative to the first body 110. The first drive motor 10 may be driven by an electrical connection or a pneumatic connection located outside the industrial structure.

[0055] As one embodiment, the first drive motor 10 can be configured so that the drive shaft is placed parallel to the rotation axis AX of the first body 110. As an example, at least one drive source such as a drive motor can be provided. For example, a drive source different from the first drive motor 10 that drives the first body 110 can be provided so as to drive the first body 110 to rotate using the driving force of the first drive motor 10 and multiple drive sources. In addition, the power of the multiple drive sources can be the same or different. When motors with different powers are provided, a control program for driving the motors can be additionally provided.

[0056] The second body 120 is disposed along a rotation axis AX and is rotatable relative to the first body 110 .

[0057] A second drive motor 20 is arranged on one side of the second body 120, and the driving force of the second drive motor 20 can transmit power to the power transmission unit 30 installed on the second body 120. Specifically, the power transmission unit 30 can be connected to a housing extending from the second body 120. The housing can have a set length and extend in the same direction as the rotation axis AX of the second body 120. For example, the joint device 100 can be constructed as follows: the power transmission unit 30 connected to the housing receives the driving force transmission, so that the end of the industrial structure can be driven according to the purpose. The second body 120 can include: a main body, the main body has a built-in connection portion that receives the driving force transmission from the second drive motor 20; and a hub 121, the hub 121 extends from the main body.

[0058] The second body 120 may include a hub 121 inserted into the rotation axis AX, and the center of the hub 121 may extend along the rotation axis AX.

[0059] A protrusion 122 may be disposed on one side of the hub 121 . The protrusion 122 may be disposed adjacent to one end 131 of the limiting portion 130 to limit the rotation of the limiting portion 130 .

[0060] The protruding portion 122 protrudes from the hub 121 by a predetermined height, and one end 131 of the limiting portion 130 can be supported on a side wall of the protruding portion 122 to limit the rotation of the second body 120 .

[0061] The protrusion 122 may have one side 122A and another side 122B along the area where the stopper 130 contacts. Figure 4When the limiting portion 130 is supported on the first protrusion 112, the one side 122A can support the other end 132 of the limiting portion 130 together with the first protrusion 112. Figure 5 , the other side 122B can support the other end 132 of the limiting portion 130 together with the second protrusion 113 when the limiting portion 130 is supported on the second protrusion 113. Therefore, the joint device 100 can be firmly supported by the dual support structure of the limiting portion 130 and the protrusion 122, so that the joint device 100 does not rotate beyond the set rotation angle.

[0062] The position-limiting portion 130 may be installed to be rotatable around the rotation axis AX. One end 131 of the position-limiting portion 130 may be attached to the rotation axis, and the other end 132 may be disposed between the first body 110 and the second body 120 .

[0063] One end 131 of the stopper 130 is inserted into the rotation axis AX and extends radially outward along the outer surface of the hub 121. In addition, the stopper 130 covers the side surface of the hub 121, and the other end 132 extends radially inward along the inner surface of the hub 121. The end 133 of the stopper 130 can be disposed between the first body 110 and the second body 120.

[0064] At this time, the overall shape of the stopper 130 can be a U-shaped hook pin shape with a predetermined placement space along the outer contour of the hub 121. For example, when the second body 120 rotates along the rotation radius, it can contact the stopper 130 and stop. Therefore, the stopper 130 can be arranged on the moving path of the second body 120 corresponding to the first body 110 to prevent the second body 120 from excessive movement.

[0065] Specifically, the limiting part 130 can rotate in either clockwise or counterclockwise direction. One end 131 of the limiting part 130 can be attached to the rotation axis AX by means of an insertion pin 135, and the limiting part 130 can rotate around the rotation axis AX.

[0066] For example, the stopper 130 can rotate relative to the first body 110 with the rotation axis AX as the center, and rotate along the edge of the hub 121. As an example, the stopper 130 can rotate with the rotation of the second body 120. For example, when the second body 120 is to rotate in a clockwise direction, the stopper 130 can be located on the right side of the second body 120. The second body 120 pushes out one side of the stopper 130 while rotating, and when the second body 120 stops after rotating, the stopper 130 can be located on the left side of the second body 120.

[0067] The problem with the joint device of the prior art is that when the two coaxially connected bodies rotate, the intersection rotation angle of the two bodies is difficult to expand to 360 degrees. In addition, even if the thickness of the conventional limiter is made to the minimum size, the rotation angle of the component elements cannot exceed 360 degrees due to the space angle occupied by the limiter itself.

[0068] In the joint device 100 of the present invention, the limiting portion 130 is disposed between the first body 110 and the second body 120, and the first body 110 and the limiting portion 130 can be rotatably connected by means of the rotation axis AX, and the first body 110 and the second body 120 can be rotatably connected by means of the rotation axis AX. That is, the first body 110, the second body 120, and the limiting portion 130 can rotate in different directions with the same axis as the center. The limiting portion 130 can rotate relative to the first body 110 or the second body 120, and can limit the rotation in one direction by means of the first protrusion 112 and the protrusion 122, and can limit the rotation in the other direction by means of the second protrusion 113 and the protrusion 122.

[0069] The working range of the second body 120 may be larger than the working range of the limiting portion 130 .

[0070] As an embodiment, the working range of the limiter 130 that can rotate relative to the first body 110 is set to the rotation angle between the first protrusion 112 and the second protrusion 113. At this time, the working range of the second body 120 that can rotate relative to the first body 110 is set to be larger than the working range of the limiter 130.

[0071] Reference Figure 4 The second body 120 is supported on the first protrusion 112 and extends along the first center line CL-A. Figure 5 If the second body 120 rotates in the clockwise direction, the second body 120 passes through the second protrusion 113 and the first protrusion 112 and is supported on the second protrusion 113. At this time, the second body 120 extends along the second center line CL-B. On the other hand, the stopper 130 can rotate from the first protrusion 112 to the second protrusion 113.

[0072] In addition, the limiting portion 130 may be set to a shape and amplitude that allows the second body 120 to rotate within a maximum working range. For example, the limiting portion 130 may be formed to have a set thickness and length.

[0073] As an example, the stopper 130 may be formed to have a width defined as the first width W1. By setting the stopper 130 to the first width W1, the second body 120 may have a working range exceeding 360 degrees.

[0074] When the second body 120 is supported on the first body 110, the first width W1 of the stopper 130 sets the distance between the protrusion of the first body 110 and the protrusion 122 of the second body 120. That is, the first width W1 of the stopper 130 can set the rotation angle of the second body 120.

[0075] Reference Figure 4 The shortest distance between the extension line of the first protrusion 112 and the second protrusion 113 and the rotation axis AX can be defined as a first distance D1, and the shortest distance between the extension line of the protrusion 122 and the rotation axis AX can be defined as a second distance D2.

[0076] As an example, Figure 4 As shown, if the first width W1 is smaller than the sum of the first distance D1 and the second distance D2, the second body 120 can be rotated more than 360 degrees relative to the first body 110.

[0077] As another embodiment, although not shown in the drawings, if the first width W1 is greater than the sum of the first distance D1 and the second distance D2 , the second body 120 may be rotated within 360 degrees relative to the first body 110 .

[0078] As another embodiment, although not shown in the drawings, if the first width W1 is equal to the sum of the first distance D1 and the second distance D2 , the second body 120 can rotate 360 ​​degrees relative to the first body 110 .

[0079] In addition, the position-limiting portion 130 may be supported by the insertion pin 135. For example, the insertion pin 135 may be coaxially inserted with the first body 110 and the second body 120. The insertion pin 135 may be inserted into an opening formed on the upper side of the position-limiting portion 130, and may be installed by passing through the second body 120 and the position-limiting portion 130.

[0080] As an example, the insertion pin 135 may be provided to have a length relatively longer than the maximum height of the stopper 130. Therefore, the insertion pin 135 may prevent the stopper 130 from being separated from the rotation axis AX during the pivoting action.

[0081] Reference Figure 2 and Figure 4 , the first body 110 and the second body 120 may be restricted from rotating at the first position.

[0082] At this time, the clockwise or counterclockwise rotation angle of the limiting portion 130 is limited by the protrusion of the first body 110. As an example, the rotation radius of the limiting portion 130 may be limited by the first protrusion 112, the second protrusion 113 and the protruding portion 122.

[0083] Reference Figure 6A first gap G may be formed between the first body 110 and the second body 120 . The first gap G is greater than a protruding height T of the first protrusion 112 , and the first protrusion 112 may be disposed radially outward of the hub 121 .

[0084] As an example, due to the predetermined height of the first interval G, the joint device 100 can ensure a space for the limiter 130 to move between the first body 110 and the second body 120. In addition, compared with the protrusion height T of the protrusion configured on the first body 110, the first interval G can be set relatively higher. Specifically, the separation distance obtained by the first interval G can ensure a predetermined interval, so that the first body 110 and the second body 120 do not interfere with each other when the second body 120 rotates relative to the first body 110. Therefore, wear and damage of the body caused by the pivoting action of the first body 110 and the second body 120 can be prevented.

[0085] One end 131 of the limiting portion 130 can be supported on one side 122A of the protruding portion 122, and the other end 132 of the limiting portion 130 can be supported on the first protrusion 112. Since the limiting portion 130 limits the rotation of the first body 110 and the second body 120, the second body 120 cannot be further rotated in the counterclockwise direction. At this time, the second body 120 is arranged along the first center line CL-A.

[0086] Reference Figure 3 and Figure 5 , the first body 110 and the second body 120 may be restricted from rotating at the second position.

[0087] One end 131 of the limiting portion 130 may be supported on the other side 122B of the protruding portion 122, and the other end 132 of the limiting portion 130 may be supported on the second protrusion 113. That is, the second body 120 may use one side 122A and the other side 122B of the protruding portion 122 formed relatively higher than the hub 121 to form a blocking edge for the limiting portion 130 to be hung.

[0088] As an optional embodiment, the second body 120 may be composed of a structure in which the body extending toward the protruding portion 122 has a predetermined inclination angle. For example, one end of the body may extend toward the hub 121, and the other end may be composed of a structure in which the inclined body gradually expands. Thus, the strength of the protruding portion 122 supporting the limiting portion 130 may be increased as the limiting portion 130 rotates.

[0089] In addition, the height of the one side 122A and the other side 122B of the protrusion 122 may be set to be the same or greater according to the height of the limiting portion 130 .

[0090] Since the limiting portion 130 limits the rotation of the first body 110 and the second body 120, the second body 120 cannot further rotate in the clockwise direction. At this time, the second body 120 is configured along the second center line CL-B. At this time, the position of the first body 110 remains unchanged, and the second body 120 and the limiting portion 130 can rotate together. The second body 120 and the limiting portion 130 rotate around the same rotation axis AX, and thus can rotate stably. In the opposite case, that is, when rotating in the counterclockwise direction, the same can also be applied. Therefore, the joint device 100 can set the rotation range of the first body 110 and the second body 120 to be greater than 360 degrees.

[0091] If the second body 120 is rotated clockwise in the first position, the second body 120 can be rotated to the second position, that is, the center line of the second body 120 can change from the first center line CL-A to the second center line CL-B, and the rotation angle of the second body 120 can exceed 360 degrees.

[0092] The first protrusion 112 and the second protrusion 113 of the first body 110 are separated from the rotation axis AX by a predetermined distance, and the protrusion 122 of the second body 120 is separated from the rotation axis AX by a predetermined distance. In addition, the stopper 130 is disposed between the first body 110 and the second body 120, and the stopper 130 can rotate around the rotation axis AX, so that the rotation range of the joint device 100 can be set to be more than 360 degrees.

[0093] The joint device 100 of one embodiment of the present invention can expand the rotation range. The stopper 130 disposed between the first body 110 and the second body 120 rotates along the rotation axis AX, so the rotation angle range between the first body 110 and the second body 120 can be set to exceed 360 degrees.

[0094] As described above, according to the structure in which the first body 110, the second body 120 and the limit part 130 are rotatably connected with the rotation axis AX as the center, the joint device 100 can improve the problems of reduced operability and long operation time when the rotation of the joint device 100 cannot reach the working area. By limiting the rotation angle, the interference between the robot arms of industrial or medical structures can be minimized.

[0095] In a factory, for safety or to avoid interference with other devices, it is required to limit the pivot range of industrial or medical structures. In addition, as the layout of the industrial structure changes, it is sometimes required to change the pivot range. In this case, the user needs to perform additional processing individually to change the position of the limiter. The industrial structure using the joint device 100 of this embodiment can change the pivot range without additional processing.

[0096] In addition, the joint device 100 of the present invention adopts a relatively simple structure and a small size of the limiting portion 130 structure, which is easy to install and convenient to use.

[0097] Figure 7 To show Figure 1 FIG. 1 is a diagram of another embodiment of a joint device 100 .

[0098] Reference Figure 7 In the case where a protrusion is disposed on the first body 110 and a protrusion is disposed on the second body 120, the second body 120 can rotate more than 360 degrees for multiple turns.

[0099] For example, the limit portion 130 can be arranged between the first body 110 and the second body 120. A protrusion 112A is arranged on the surface 111 of the first body 110. The A protrusion 112A can be formed in a shape protruding along the diameter direction perpendicular to the rotation axis AX. The A protrusion 112A can have a first surface S1 and a second surface S2 facing each other. For example, when the second body 120 stops at the position of the first center line CL-A, one side 122A of the second body 120 can contact one side of the limit portion 130, and the other side of the limit portion 130 can be in a state of contacting the first surface S1 of the A protrusion 112A. If the second body 120 rotates in the clockwise direction of the first body 110, the second body 120 can pass over the A protrusion 112A, and the other side 122B of the second body 120 can contact the other side of the limit portion 130 and rotate more than 360 degrees. When one side of the limiter 130 contacts the second surface S2 of the A protrusion 112A, the second body 120 can be supported by the A protrusion 112A. At this time, the maximum working range of the second body 120 exceeds 360 degrees, and multiple rotations can be achieved at an angle greater than the working range of the limiter 130.

[0100] As mentioned above, the present invention is described with reference to an embodiment shown in the accompanying drawings, but this is only exemplary, and anyone with common sense in the corresponding technical field will understand that various modifications and variations of the embodiments can be made. Therefore, the true technical protection scope of the present invention should be determined by the technical ideas of the attached claims.

Claims

1. A joint device, comprising: a first body having a rotation axis; a second body, the second body being arranged along the rotation axis and being rotatable relative to the first body; and Limiting part, The characteristic is that one end of the limiting part is mounted on the rotating shaft, and the other end is arranged between the first body and the second body, and can rotate around the rotating shaft.

2. The joint device according to claim 1, further comprising: A driving motor is disposed on at least one of the first body and the second body to rotate the first body or the second body.

3. The joint device according to claim 1, wherein: The first entity has: A first protrusion, the first protrusion contacts the other end of the limiting portion to limit the rotation angle; and A second protrusion is spaced apart from the first protrusion and contacts the other end of the limiting portion to limit the rotation angle.

4. The joint device according to claim 3, wherein: The second subject comprises: a protrusion, the protrusion being arranged adjacent to one end of the limiting portion to limit the rotation of the limiting portion; When the second body rotates in one direction, one end of the limiting portion is supported on one side of the protruding portion, and the other end is supported on the first protrusion. When the second body rotates in another direction, the one end is supported on the other side of the protruding portion, and the other end is supported on the second protrusion.

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