Mechanical arm

Abstract

The invention discloses a mechanical arm which comprises a first arm part and a second arm part, and the first arm part and the second arm part are rotationally connected. The first arm part driving piece is arranged on the first arm part; and the connecting rod assembly is connected with the first arm part and the second arm part, and the first arm part driving piece is connected with the connecting rod assembly, so that the first arm part driving piece can drive the second arm part to move between the initial position and the limiting position. According to the mechanical arm provided by the embodiment of the invention, the first arm part driving piece is arranged on the first arm part, and the connecting rod assembly is arranged to be connected with the first arm part and the second arm part, so that the first arm part driving piece can drive the second arm part to rotate relative to the first arm part through the connecting rod assembly; according to the mechanical arm, the occupied space of the first arm driving part at the joint of the first arm part and the second arm part can be reduced, the whole mechanical arm can be more compact, the first arm driving part can be prevented from protruding out of the human body envelope, and the anthropomorphic effect of the mechanical arm can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and in particular to a robotic arm. Background Art

[0002] In the related art, existing robotic arms generally use a drive motor to directly drive the forearm to rotate and lift, which causes the drive motor to occupy additional space at the robotic arm joints (such as the elbow joints) and easily protrude from the human body envelope, leaving room for improvement. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a robotic arm with a more compact structure and a good anthropomorphic effect.

[0004] According to an embodiment of the present invention, the robotic arm includes: a first arm portion and a second arm portion, the first arm portion and the second arm portion being rotatably connected; a first arm portion driving member, the first arm portion driving member being arranged on the first arm portion; a connecting rod assembly, the connecting rod assembly connecting the first arm portion and the second arm portion, the first arm portion driving member being connected to the connecting rod assembly so that the first arm portion driving member can drive the second arm portion to move between an initial position and an extreme position.

[0005] According to the robotic arm of an embodiment of the present invention, a first arm driving component is provided on the first arm portion, and a connecting rod assembly is provided to connect the first arm portion and the second arm portion respectively, so that the first arm driving component can drive the second arm portion to rotate relative to the first arm portion through the connecting rod assembly, thereby reducing the space occupied by the first arm driving component at the connection between the first arm and the second arm, making the robotic arm as a whole more compact, and preventing the first arm driving component from protruding from the human body envelope, thereby improving the anthropomorphic effect of the robotic arm.

[0006] According to some embodiments of the present invention, the connecting rod assembly and the lower part of the first arm, the upper part of the second arm, the hinge point of the driving end of the first arm driving member, and the hinge point of the first arm and the second arm form a polygon, and the polygon is a quadrilateral.

[0007] In some embodiments, the connecting rod assembly includes a first connecting rod and a second connecting rod, the two ends of the first connecting rod are respectively rotatably connected to the first arm and the driving end of the first arm driving member, the two ends of the second connecting rod are respectively rotatably connected to the driving end of the first arm driving member and the second arm, and the angle between the first connecting rod and the second connecting rod is less than 90°.

[0008] In some embodiments, at the initial position, an inner angle of the polygon at a hinge point between the first arm and the second arm is greater than 90°, and an inner angle of the polygon at a hinge point between the first arm and the first link is less than 90°.

[0009] In some embodiments, the first arm includes a support frame, and the end of the support frame close to the second arm includes two supporting legs, the second arm is rotatably connected to the two supporting legs respectively, and the first connecting rod is rotatably connected to at least one of the supporting legs, wherein an avoidance space is formed between the two supporting legs, and in the extreme position, part of the second arm is located in the avoidance space.

[0010] In some embodiments, the first connecting rod includes a first support rod and two second support rods connected to each other, the first support rod is connected to the first arm driving member, and the two second support rods are located between the two support legs and are respectively connected to the two support legs in a one-to-one correspondence.

[0011] In some embodiments, the two legs are connected by a fixed axis, and the hinge points form a polygon located on the radial outer periphery of the fixed axis.

[0012] In some embodiments, the support frame defines a accommodating cavity with one side open, the first arm driving member is located on the open side of the support frame, and when the first arm driving member drives the second arm, a portion of the first arm driving member can extend into the accommodating cavity.

[0013] In some embodiments, the first arm driving member includes a first arm motor, a telescopic rod and a connecting shaft. The first arm motor can drive the telescopic rod to extend or shorten. The axis of the connecting shaft is perpendicular to the telescopic direction of the telescopic rod. The middle part of the connecting shaft is rotatably connected to the telescopic rod, and the first connecting rod and the second connecting rod are respectively rotatably connected to the two ends of the connecting shaft.

[0014] According to some embodiments of the present invention, the swing angle of the second arm is 0-145°.

[0015] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0017] Figure 1 is a schematic structural diagram of a robotic arm according to some embodiments of the present invention;

[0018] Figure 2 is a schematic diagram of a partial structure of a robotic arm according to some embodiments of the present invention;

[0019] Figure 3 yes Figure 2 The structure shown is a schematic diagram of a local structure at one viewing angle;

[0020] Figure 4 yes Figure 2 A schematic diagram of the local structure of the structure shown in another perspective;

[0021] Figure 5 is a schematic structural diagram of a connecting rod assembly according to some embodiments of the present invention at a certain viewing angle;

[0022] Figure 6 is a schematic structural diagram of a connecting rod assembly according to some embodiments of the present invention from another perspective;

[0023] Figure 7 is a schematic structural diagram of a first arm according to some embodiments of the present invention;

[0024] Figure 8 is a schematic diagram of the partial structure of the first arm according to some embodiments of the present invention.

[0025] Reference numerals:

[0026] Robotic arm 100,

[0027] First arm 11, first arm driving member 111, first arm motor 1111, telescopic rod 1112, connecting shaft 1113, support frame 112, support leg 1121, avoidance space 1122, accommodating cavity 1123, support plate 113, fixed shaft 114, second arm 12,

[0028] Connecting rod assembly 40 , first connecting rod 41 , first support rod 411 , second support rod 412 , second connecting rod 42 . DETAILED DESCRIPTION

[0029] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0031] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0032] Reference below Figures 1-8 A robotic arm 100 according to an embodiment of the present invention is described.

[0033] like Figures 1-8 As shown, the robotic arm 100 according to an embodiment of the present invention may include a first arm 11, a second arm 12, a first arm driving member 111 and a connecting rod assembly 40. The first arm 11 and the second arm 12 can be rotatably connected, the first arm driving member 111 can be set on the first arm 11, the connecting rod assembly 40 can connect the first arm 11 and the second arm 12, and the first arm driving member 111 can be connected to the connecting rod assembly 40 so that the first arm driving member 111 can drive the second arm 12 to move between an initial position and an extreme position.

[0034] That is, the connecting rod assembly 40 can be arranged at the connection between the first arm 11 and the second arm 12 (such as the elbow joint), and the first arm driving component 111 can be installed on the first arm 11 and drive the second arm 12 to rotate relative to the first arm 11 through the connecting rod assembly 40, which can reduce the space occupied by the first arm driving component 111 at the connection between the first arm 11 and the second arm 12, so that the space at the connection between the first arm 11 and the second arm 12 can be more compact, and the overall robotic arm 100 can be more compact, and the first arm driving component 111 can be prevented from protruding from the human body envelope, thereby improving the aesthetics of the robotic arm 100 and improving the anthropomorphic effect of the robotic arm 100.

[0035] According to the robotic arm 100 of an embodiment of the present invention, a first arm driving component 111 is provided on the first arm 11, and a connecting rod assembly 40 is provided to be connected to the first arm 11 and the second arm 12 respectively, so that the first arm driving component 111 can drive the second arm 12 to rotate relative to the first arm 11 through the connecting rod assembly 40, which can reduce the space occupied by the first arm driving component 111 at the connection between the first arm 11 and the second arm 12, make the robotic arm 100 more compact as a whole, and prevent the first arm driving component 111 from protruding from the human body envelope, thereby improving the anthropomorphic effect of the robotic arm 100.

[0036] like Figure 1 As shown, in the present application, the robot may include two robotic arms 100, which are movably arranged on opposite sides of the robot body, that is, the two robotic arms 100 may be the left arm and the right arm of the robot, and the robotic arm 100 described below may be the right arm of the robot.

[0037] like Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, according to some embodiments of the present invention, the connecting rod assembly 40 can be hinged to the lower part of the first arm 11, the connecting rod assembly 40 can be hinged to the upper part of the second arm 12, the connecting rod assembly 40 can be hinged to the driving end of the first arm driving member 111, and the first arm 11 can be hinged to the second arm 12, and the above-mentioned four hinge points can form a polygon, which can be a quadrilateral.

[0038] That is, the first arm 11, the second arm 12 and the connecting rod assembly 40 can cooperate with each other to form a four-bar linkage between the first arm 11 and the second arm 12, which is beneficial to increase the rotation angle range of the second arm 12 relative to the first arm 11 (such as the maximum rotation angle can reach 145°), and is beneficial to improve the relative rotation efficiency of the second arm 12 and the first arm 11, thereby increasing the range of movement of the second arm 12, and improving the flexibility of the second arm 12, and improving the anthropomorphic effect of the robotic arm 100.

[0039] It can be understood that the first arm driving member 111 can be rotatably connected to the first arm 11, the first arm driving member 111 can be connected to the second arm 12 through the connecting rod assembly 40, the first arm driving member 111 can be a linear push rod motor, and the driving end of the telescopic rod 1112 of the linear push rod motor can be rotatably connected to the connecting rod of the connecting rod assembly 40, so that the first arm driving member 111 can drive the second arm 12 to rotate relative to the first arm 11, which can increase the range of motion of the second arm 12 and improve the flexibility of the movement of the second arm 12.

[0040] Of course, the driving end of the telescopic rod 1112 and the connecting rod assembly 40 can be connected by a ball joint, which can increase the degree of freedom of the connection between the first arm driving component 111 and the connecting rod assembly 40, and the first arm driving component 111 and the first arm 11 can be connected by a ball joint, which can increase the degree of freedom of the connection between the first arm driving component 111 and the first arm 11, so that the first arm driving component 111 can fine-tune its own position when the second arm 12 moves, which can increase the range of movement of the second arm 12 and improve the flexibility of the movement of the second arm 12.

[0041] like Figure 3 、 Figure 4 、 Figure 5 and Figure 6 As shown, in some embodiments, the connecting rod assembly 40 may include a first connecting rod 41 and a second connecting rod 42, and the two ends of the first connecting rod 41 can be rotatably connected to the driving end of the first arm 11 and the first arm driving member 111, respectively, so that the hinge point located at the driving end of the first arm driving member 111 can rotate around the hinge point located between the first connecting rod 41 and the first arm 11, and the two ends of the second connecting rod 42 can be rotatably connected to the driving end of the first arm driving member 111 and the second arm 12, respectively, so that the first arm driving member 111 can drive the second connecting rod 42 to move, thereby driving the second arm 12 to rotate relative to the first arm 11.

[0042] Among them, the angle between the first link 41 and the second link 42 can be less than 90°, which is conducive to the first arm driving component 111 driving the second arm 12 to rotate in the direction close to the first arm 11 (such as lifting the forearm) through the connecting rod assembly 40, which is conducive to optimizing the above-mentioned four-bar linkage, increasing the rotation angle range of the second arm 12 relative to the first arm 11, and improving the minimum equivalent torque of the second arm 12 when rotating relative to the first arm 11, and improving the relative rotation efficiency of the second arm 12 and the first arm 11, thereby increasing the range of movement of the second arm 12, and improving the flexibility of the second arm 12 movement, and improving the anthropomorphic effect of the robotic arm 100.

[0043] like Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, in some embodiments, when the second arm 12 is in the initial position, the internal angle of the above-mentioned polygon at the hinge point of the first arm 11 and the second arm 12 can be greater than 90°, and the internal angle of the above-mentioned polygon at the hinge point of the first arm 11 and the first connecting rod 41 can be less than 90°, which is conducive to the first arm driving member 111 driving the second arm 12 to rotate in the direction close to the first arm 11 through the connecting rod assembly 40 (such as lifting the forearm), which is conducive to optimizing the above-mentioned four-bar linkage, increasing the rotation angle range of the second arm 12 relative to the first arm 11, and improving the minimum equivalent torque of the second arm 12 when rotating relative to the first arm 11, and improving the relative rotation efficiency of the second arm 12 and the first arm 11, thereby increasing the range of movement of the second arm 12, and improving the flexibility of the second arm 12 movement, and improving the anthropomorphic effect of the robotic arm 100.

[0044] like Figure 1 、 Figure 2 、 Figure 7 and Figure 8 As shown, in some embodiments, the first arm 11 may include a support frame 112, and one end of the support frame 112 close to the second arm 12 (such as Figure 7 The lower end shown in the figure may include two supporting legs 1121, and the second arm 12 may be rotatably connected to the two supporting legs 1121 respectively, so that the second arm 12 can rotate relative to the first arm 11, and the first connecting rod 41 may be rotatably connected to one supporting leg 1121, which can ensure that the first arm driving member 111 can normally drive the second arm 12 to rotate relative to the first arm 11 through the connecting rod assembly 40. Alternatively, the first connecting rod 41 can be rotatably connected to the two supporting legs 1121, which can improve the reliability and stability of the rotation of the second arm 12 relative to the first arm 11.

[0045] Among them, an avoidance space 1122 can be formed between the two legs 1121. When the second arm 12 is in the extreme position, part of the second arm 12 can be located in the avoidance space 1122, which can achieve avoidance of the second arm 12 and prevent the second arm 12 from interfering with the first arm 11 during the rotation process, thereby increasing the range of movement of the second arm 12, and improving the flexibility of the second arm 12, which can improve the anthropomorphic effect of the robotic arm 100.

[0046] like Figure 3 、 Figure 4 、 Figure 5 and Figure 6As shown, in some embodiments, the first connecting rod 41 may include a first support rod 411 and two second support rods 412. The first support rod 411 and the two second support rods 412 may be connected to each other. The first support rod 411 may be connected to the driving end of the telescopic rod 1112 of the first arm driving member 111, that is, one end of the first support rod 411 may be hinged to the driving end of the telescopic rod 1112, and the two second support rods 412 may be located between the two support legs 1121, and the two second support rods 412 may be respectively connected to the two support legs 1121 one by one.

[0047] That is, one end of the two second support rods 412 can be connected to the other end of the first support rod 411 respectively, and the two second support rods 412 can be located on opposite sides of the first support rod 411 (such as Figure 3 The other ends of the two second support rods 412 can be hinged to the two support legs 1121 respectively, so that the first connecting rod 41 and the two support legs 1121 can be rotatably connected, thereby improving the reliability and stability of the rotation of the second arm 12 relative to the first arm 11.

[0048] like Figure 1 、 Figure 2 、 Figure 3 and Figure 7 As shown, in some embodiments, the two support legs 1121 can be connected by a fixed shaft 114, which can improve the structural strength of the support frame 112 at the support legs 1121, and the above-mentioned four hinge points can be surrounded by a polygon, and the polygon can be located on the radial outer periphery of the fixed shaft 114. On the one hand, the support legs 1121 can be evenly stressed when the second arm 12 rotates relative to the first arm 11, which can improve the service life of the support frame 112. On the other hand, it can prevent the above-mentioned four-bar linkage from interfering with the fixed shaft 114 when the second arm 12 rotates relative to the first arm 11, which can improve the reliability and stability of the rotation of the second arm 12 relative to the first arm 11.

[0049] like Figure 1 、 Figure 2 、 Figure 7 and Figure 8 As shown, in some embodiments, the support frame 112 may define a receiving cavity 1123, and the receiving cavity 1123 may have one side (such as Figure 8 The front side shown in FIG1 is open, and the first arm driving member 111 can be located on the open side of the support frame 112 (as shown in FIG1 ). Figure 8 The front side is shown in FIG, and when the first arm driving member 111 drives the second arm 12, a portion of the first arm driving member 111 can extend into the accommodating cavity 1123.

[0050] In this way, the first arm driving component 111 can be hidden, the aesthetics of the robot arm 100 can be improved, the first arm driving component 111 can be protected, the reliability of the rotation of the second arm 12 relative to the first arm 11 can be improved, and at the same time, the space occupied by the first arm driving component 111 at the connection between the first arm 11 and the second arm 12 can be reduced, so that the robot arm 100 as a whole can be more compact, the first arm driving component 111 can be prevented from protruding from the human body envelope, and the anthropomorphic effect of the robot arm 100 can be improved.

[0051] The first arm 11 may further include a support plate 113, an end of the support frame 112 away from the second arm 12 (such as Figure 7 The upper end shown in the figure can be connected to the support plate 113, and the first arm driving member 111 can be connected to the first arm 11 through a ball joint or a universal joint, which can increase the degree of freedom of the connection between the first arm driving member 111 and the first arm 11, so that the first arm driving member 111 can fine-tune its own position when the second arm 12 moves, thereby increasing the range of movement of the second arm 12 and improving the flexibility of the movement of the second arm 12.

[0052] like Figure 1 、 Figure 2 and Figure 7 As shown, in some embodiments, the first arm driving member 111 may include a first arm motor 1111, a telescopic rod 1112 and a connecting shaft 1113. The first arm motor 1111 can drive the telescopic rod 1112 to extend or shorten. The axis of the connecting shaft 1113 can be perpendicular to the telescopic direction of the telescopic rod 1112, and the middle part of the connecting shaft 1113 can be rotatably connected to the telescopic rod 1112.

[0053] The first connecting rod 41 and the second connecting rod 42 can be connected to the two ends of the connecting shaft 1113 (such as Figure 7 The left and right ends (as shown) are rotatably connected, so that the telescopic rod 1112 of the first arm motor 1111 can be telescoped to drive the connecting rod assembly 40 to move and drive the second arm 12 to rotate relative to the first arm 11, thereby ensuring that the first arm driving member 111 can normally drive the second arm 12 to rotate relative to the first arm 11 through the connecting rod assembly 40, and can improve the reliability and stability of the rotation of the second arm 12 relative to the first arm 11.

[0054] like Figure 3 and Figure 4As shown, according to some embodiments of the present invention, the angle at which the second arm 12 rotates relative to the first arm 11 is the swing angle of the second arm 12. If the swing angle of the second arm 12 is too large, the anthropomorphism of the robotic arm 100 is affected. Therefore, the swing angle of the second arm 12 can be limited to a range of 0-145°, the range of motion of the second arm 12 can be increased, and the flexibility of the second arm 12 can be improved, thereby improving the anthropomorphic effect of the robotic arm 100. When the second arm 12 is in the initial position, the angle between the second arm 12 and the first arm 11 is the largest (the forearm hangs down naturally), and when the second arm 12 is in the extreme position, the angle between the second arm 12 and the first arm 11 is the smallest (the forearm is raised).

[0055] The other components and operations of the robotic arm 100 according to the embodiment of the present invention are well known to those skilled in the art and will not be described in detail here. In the description of the present invention, "first feature" and "second feature" may include one or more of these features. The vertical direction, left-right direction, and front-back direction are based on the vertical direction, left-right direction, and front-back direction shown in the figure.

[0056] In the description of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or the first and second features being in contact not directly but through another feature therebetween. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is at a higher level than the second feature.

[0057] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0058] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A robotic arm, characterized in that: include: a first arm portion and a second arm portion, wherein the first arm portion and the second arm portion are rotatably connected; a first arm driving member, wherein the first arm driving member is provided on the first arm; A connecting rod assembly connects the first arm and the second arm, and the first arm driving member is connected to the connecting rod assembly so that the first arm driving member can drive the second arm to move between an initial position and an extreme position.

2. The robotic arm according to claim 1, wherein: The connecting rod assembly, the lower part of the first arm, the upper part of the second arm, the hinge point where the driving end of the first arm driving member is hinged, and the hinge point between the first arm and the second arm form a polygon, and the polygon is a quadrilateral.

3. The robotic arm according to claim 2, wherein: The connecting rod assembly includes a first connecting rod and a second connecting rod, the two ends of the first connecting rod are respectively rotatably connected to the first arm and the driving end of the first arm driving member, the two ends of the second connecting rod are respectively rotatably connected to the driving end of the first arm driving member and the second arm, and the angle between the first connecting rod and the second connecting rod is less than 90°.

4. The robotic arm according to claim 3, wherein: In the initial position, an internal angle of the polygon at a hinge point between the first arm and the second arm is greater than 90°, and an internal angle of the polygon at a hinge point between the first arm and the first link is less than 90°.

5. The robotic arm according to claim 3, wherein: The first arm portion includes a support frame, and one end of the support frame close to the second arm portion includes two supporting legs. The second arm portion is rotatably connected to the two supporting legs respectively, and the first connecting rod is rotatably connected to at least one of the supporting legs, wherein an avoidance space is formed between the two supporting legs. In the extreme position, part of the second arm portion is located in the avoidance space.

6. The robotic arm according to claim 5, characterized in that: The first connecting rod includes a first support rod and two second support rods connected to each other, the first support rod is connected to the first arm driving component, and the two second support rods are located between the two support legs and are respectively connected to the two support legs in a one-to-one correspondence.

7. The robotic arm according to claim 5, characterized in that: The two legs are connected via a fixed axis, and the hinge points form a polygon located on the radial outer periphery of the fixed axis.

8. The robotic arm according to claim 5, wherein: The support frame defines a accommodating cavity with one side open, the first arm driving member is located on the open side of the support frame, and when the first arm driving member drives the second arm, a portion of the first arm driving member can extend into the accommodating cavity.

9. The robotic arm according to claim 3, wherein: The first arm driving component includes a first arm motor, a telescopic rod and a connecting shaft. The first arm motor can drive the telescopic rod to extend or shorten. The axis of the connecting shaft is perpendicular to the telescopic direction of the telescopic rod. The middle part of the connecting shaft is rotatably connected to the telescopic rod, and the first connecting rod and the second connecting rod are rotatably connected to the two ends of the connecting shaft respectively.

10. The robotic arm according to any one of claims 1 to 9, characterized in that: The swing angle of the second arm portion is 0-145°.

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