A prosthetic hand

Abstract

The present invention discloses a prosthetic hand, including a palm component and a finger component, wherein the finger component at least includes a thumb component and an index finger component, and the palm component includes a housing and a driving device, wherein a chamber is formed in the housing, the driving device is arranged in the chamber, and is drivingly connected with the finger component located at the upper end of the housing, the driving device includes a first driving motor and a first lead screw connected with the first driving motor, a driving connection is formed between the first lead screw and the index finger component, and is used to drive the index finger component to move up and down; the thumb component is a passive thumb component arranged on the housing, and forms a front opening and closing with the index finger component. The present invention provides a driving device connected with the index finger component in the housing, the driving device adopts a lead screw transmission mode, and the thumb component is set to a passive form, thereby reducing the number of driving motors, which is conducive to reducing the size and weight of the palm, and is suitable for disabled people of different age groups.

Description

Technical Field

[0001] The present invention relates to the technical field of bionic hands, and in particular to a prosthetic hand. Background Art

[0002] The control of intelligent prosthetic hands mostly adopts myoelectric control, which uses tiny myoelectric potential difference signals as the initial signals to control and manipulate various functions of the myoelectric prosthesis, thereby achieving the control of the opening and closing of the prosthetic hand and other actions.

[0003] At present, an important challenge in the field of prosthetic hand research is to design a multi-freedom prosthetic hand that is light in weight, small in size, has high output force and flexible movement. The existing driving method of intelligent prosthetic hands mainly uses a complex gear set transmission structure to achieve various hand movements. Although it has high control accuracy, it also has problems such as high failure rate, heavy weight and high cost, which is not conducive to the promotion and application of prosthetic hands.

[0004] At the same time, the use of gear transmission to accurately control the prosthetic hand will cause the palm area to be larger, exceeding the size of a normal human hand, and not aesthetically pleasing. In response to the above-mentioned technical problems, there is also a structure in the prior art that controls the movement of finger joints by pulling wires driven by motors. Although the weight is reduced compared with the multi-degree-of-freedom movement of fingers driven by gears, in order to improve the accuracy of the operation, more than a dozen sets of pulling wire motor groups are required, which results in a large power drive module and a complex pulling wire routing method. Summary of the invention

[0005] In view of the above deficiencies in the prior art, the present invention provides a prosthetic hand that is designed to better meet the needs of users in combination with the user's usage conditions. The size of the entire hand can be made closer to users of different age groups according to the different needs of the user groups. The structure is simple, the weight is light, and the difficulty of assembly is significantly reduced.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A prosthetic hand comprises a palm component and a finger component, wherein the finger component comprises at least a thumb component and an index finger component, the palm component comprises a shell and a driving device, a chamber is formed in the shell, the driving device is arranged in the chamber and forms a driving connection with the finger component located at the upper end of the shell, the driving device comprises a first driving motor and a first lead screw connected to the first driving motor, a driving connection is formed between the first lead screw and the index finger component for driving the index finger component to move up and down; the thumb component is a passive thumb component arranged on the shell, and forms a front opening and closing with the index finger component.

[0008] The finger assembly includes a thumb assembly, an index finger assembly, a middle finger assembly, a little finger assembly and a ring finger assembly. The driving device also includes a second driving motor and a second lead screw connected to the second driving motor. The second lead screw is connected to the middle finger assembly, the little finger assembly and the ring finger assembly through a pull rod to form a synchronous displacement connection.

[0009] The pull rod is a three-finger pull rod, and an active hinged portion hinged to the second lead screw is provided in the middle portion of the pull rod, and three passive hinged portions are provided on the other side of the pull rod corresponding to the active hinged portion, and the passive hinged portions are respectively hinged to the middle finger assembly, little finger assembly and ring finger assembly.

[0010] The index finger assembly, the middle finger assembly, the little finger assembly and the ring finger assembly all include an upper joint and a lower joint, the upper end of the housing is fixed with a hinge seat hinged to each of the index finger assembly, the middle finger assembly, the little finger assembly and the ring finger assembly, the hinge seat is provided with a first hinge hole close to the inner lower part and a second hinge hole close to the outer upper part, and the lower end of the upper joint is respectively provided with a third hinge hole on the outer side and a fourth hinge hole on the inner side;

[0011] One end of the lower joint is rotationally connected to the first hinge hole via a rotating shaft, and the other end thereof is rotationally connected to the third hinge hole of the upper joint via a rotating shaft; the fourth hinge hole of the upper joint is rotationally connected to one end of the connecting rod via a rotating shaft, and the other end of the connecting rod is rotationally connected to the second hinge hole via a rotating shaft; an arc-shaped long hole is formed on the lower joint, and the arc-shaped long hole is an arc formed with the first hinge hole as the axis, and a pulling shaft is arranged in the arc-shaped long hole, and the pulling shaft is connected to the pulling rod via a hinge chain, and a torsion spring is also arranged on the rotating shaft at the position of the third hinge hole.

[0012] Furthermore, the thumb assembly includes a base, a limit frame and a thumb, the limit frame is arranged on the base, and the base is fixedly connected to the shell; a first slide groove is formed on the limit frame, and the lower end of the thumb is connected to the first slide groove through a pin shaft connector, and the thumb moves up and down along the first slide groove.

[0013] The limiting frame includes a fixed plate and support blocks arranged at both ends of the fixed plate, the first slide groove is formed on the side of the fixed plate, and the outer end surface of the fixed plate is formed with a second slide groove connected to the first slide groove, and a square slider is arranged at the lower end of the thumb, and the square slider is arranged in the second slide groove and extends into the first slide groove. The square slider is connected to the first slide groove by a pin shaft connecting member that passes through the first slide groove, and the square slider is slidably connected to the second slide groove.

[0014] The outer end surface of the fixing plate is in an arc shape that bulges outward, and the first sliding groove is an arc-shaped sliding groove that is arranged parallel to the outer end surface of the fixing plate.

[0015] A bottom plate is also arranged on the base, and the bottom plate is fixed to the base through a fixing shaft. A fixing block is respectively arranged at both ends of the bottom plate. The fixing block is rotationally connected to the support blocks arranged at both ends of the limiting frame through fixing connecting pieces, and the limiting frame rotates left and right along the fixing connecting pieces.

[0016] The fixing shaft is a universal shaft with a spherical end cover, and the bottom plate is in contact with the spherical end cover of the fixing shaft.

[0017] The arc angle formed by the thumb moving up and down along the first slide groove is less than or equal to 80 degrees; the limit frame rotates with the fastening connectors arranged at both ends as the rotation axis, and the rotation angle formed is less than or equal to 90 degrees.

[0018] A rotating arm is also fixed at the lower end of the shell, and the rotating arm includes a cylindrical support, a rotating body and a circuit board. Both ends of the cylindrical support are open, and the rotating body is arranged at an open position at one end of the cylindrical support and forms a relatively rotating connection with the inner side surface of the cylindrical support. The circuit board is fixed inside the cylindrical support, and an electric slip ring is provided on the rotating body. The electric slip ring includes an upper slip ring and a lower slip ring that are electrically connected. The upper slip ring is relatively rotationally connected to the lower slip ring, and the lower slip ring is electrically connected to the circuit board through a connecting wire.

[0019] The technical solution of the present invention has the following advantages:

[0020] A. The present invention provides a driving device connected to the index finger assembly in the housing. The driving device adopts a screw transmission mode. At the same time, the thumb assembly is set to a passive form, which reduces the number of driving motors and is beneficial to reducing the size of the palm. Under the premise of ensuring the accuracy of the index finger assembly on the driving housing, the screw transmission mode can greatly simplify the transmission structure and reduce the weight of the prosthetic hand, which is suitable for disabled people of different age groups.

[0021] B. At the same time, the present invention uses a screw drive device to independently drive the index finger, and uses another independent screw drive device to synchronously drive the middle finger assembly, the little finger assembly and the ring finger assembly. Only two drive motors are arranged in the chamber of the shell. The structure is simple. Compared with the prosthetic hand in the prior art, the weight of the entire prosthetic hand of the present invention is light and low in cost. It is more convenient for disabled people to independently hold and pinch the prosthetic hand for a long time.

[0022] C. The present invention sets a first slide groove and a second slide groove on the limit frame, and the slider at the lower end of the thumb moves up and down along the second slide groove, so that the thumb moves up and down along the second slide groove. At the same time, the opening and closing damping size of the thumb can be adjusted by applying different tightening forces to the pin shaft connector, which is beneficial to control the pinching force of the thumb and improve the pinching efficiency of the thumb. The square slider cooperates with the second slide groove on the limit frame to limit the thumb to only open and close up and rotate left and right, avoiding the thumb rotating around itself, making it more convenient for disabled people to operate.

[0023] D. In the present invention, the fixed blocks at both ends of the limit frame and the fixed blocks on the base are connected to each other in relative rotation through a fixing connector. By controlling the fixing force of the fixing connector, the holding force applied to the limit frame to enable it to rotate left and right can be well controlled, thereby realizing the passive side pinching function of the thumb. Combined with the up and down opening and closing function of the thumb, the thumb can move in multiple degrees of freedom. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a schematic diagram of the overall structure of the prosthetic hand provided by the present invention;

[0026] Figure 2 yes Figure 1 The cross-sectional view shown;

[0027] Figure 3 yes Figure 1 Schematic diagram of the shell structure shown;

[0028] Figure 4 It is a schematic diagram of the connection structure between the driving device and the pull rod;

[0029] Figure 5 yes Figure 4 A cross-sectional view of the structure shown;

[0030] Figure 6 A schematic diagram of the structure of the finger assembly located at the upper end of the housing;

[0031] Figure 7 yes Figure 6 A stereoscopic view of the lower joint structure;

[0032] Figure 8 is a schematic diagram of the thumb assembly structure;

[0033] Fig. 9 yes Figure 8 A top view of the structure shown;

[0034] Fig.10 A schematic diagram of the frontal pinching action of the thumb of the passive prosthetic hand provided by the present invention;

[0035] Fig.11 is a cross-sectional view of the rotating wrist structure provided by the present invention;

[0036] Fig.12 It is a schematic diagram of the side pinching action of the thumb of the passive prosthetic hand provided by the present invention.

[0037] Description of reference numerals:

[0038] 1-Palm component

[0039] 11- Shell

[0040] 111-Hinged seat

[0041] 12-Drive device

[0042] 121-1 first drive motor, 122-1 first lead screw

[0043] 121-2- second drive motor, 122-2 second lead screw

[0044] 122a bearing seat, 122b support frame, 122c bearing, 122d screw, 122e clamping sleeve, 122f nut rod, 122g pressure ring

[0045] 123-Tie rod

[0046] 1231-active hinge, 1232-passive hinge

[0047] 124-1 driving gear, 124-2 passive gear

[0048] 2- Finger Assembly

[0049] 21- Thumb assembly

[0050] 211-Base

[0051] 212-Limiting frame

[0052] 2121-fixed plate, 2122-support block,

[0053] 213-thumb, 2131-square slider

[0054] 22-index finger component, 23-middle finger component, 24-little finger component, 25-ring finger component

[0055] 3-base plate; 4-pin connector; 5-rotating shaft, 51-spherical end cover; 6-fixing block; 7-fastening connector

[0056] 8-Rotate wrist

[0057] 81-cylindrical support, 82-rotating body, 83-circuit board

[0058] 84-Electric slip ring

[0059] 841-upper slip ring, 842-lower slip ring

[0060] 85-Connecting wire

[0061] 86-Connection plate

[0062] 9A-Upper joint

[0063] 9B-Lower joint

[0064] 9B-1 arc-shaped long hole

[0065] 10-pulling shaft; 20-hinged chain; 30-connecting rod; 40-rotating shaft; 50-torsion spring

[0066] A-first chute; B-second chute

[0067] C1-first hinge hole, C2-second hinge hole

[0068] D1-the third hinge hole, D2-the fourth hinge hole. DETAILED DESCRIPTION

[0069] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0070] like Figure 1 and Figure 2As shown, the present invention provides a prosthetic hand, including a palm component 1 and a finger component 2, wherein the finger component 2 includes at least a thumb component 21 and an index finger component 22, the palm component 1 includes a shell 11 and a driving device 12, a chamber is formed in the shell 11, the driving device 12 is arranged in the chamber, and forms a driving connection with the finger component 2 located at the upper end of the shell 11, the driving device 12 includes a first driving motor 121-1 and a first lead screw 122-1 connected to the first driving motor 121-1, a driving connection is formed between the first lead screw 122-1 and the index finger component 22, and is used to drive the index finger component 22 to move up and down; the thumb component 21 is a passive thumb component arranged on the shell 11, and forms a front opening and closing with the index finger component 22. The present invention sets a driving motor in the shell to drive the first screw to move up and down, so as to complete the up and down movement of the index finger component 22. The thumb component adopts a passive form. By swinging the thumb component with a healthy hand, the opening and closing action between the thumb and the index finger can also be well realized. The structure is simple, the driving components are few, and the palm can be made small enough, which is suitable for younger disabled people.

[0071] The finger assembly 2 here includes a thumb assembly 21, an index finger assembly 22, a middle finger assembly 23, a pinky assembly 24 and a ring finger assembly 25, and the driving device 12 also includes a second driving motor 121-2 and a second lead screw 122-2 connected to the second driving motor 121-2, and the second lead screw 122-2 is connected to the middle finger assembly 23, the pinky assembly 24 and the ring finger assembly 25 through a pull rod 123 to form a synchronous displacement connection. Of course, the finger assembly 2 can also be provided with one of the middle finger assembly, the pinky assembly and the ring finger assembly or a combination thereof.

[0072] like Figure 4 and Figure 5 As shown, the pull rod 123 used in the present invention is preferably a three-finger pull rod, and an active hinged portion 1231 hinged to the second lead screw 122-2 is provided in the middle portion of the pull rod 123, and three passive hinged portions 1232 are provided on the other side of the pull rod 123 corresponding to the active hinged portion 1231, and the passive hinged portions 1232 are respectively hinged to the middle finger assembly 23, the little finger assembly 24 and the ring finger assembly 25. The second lead screw 122-2 drives the three fingers connected to the pull rod 123 to realize synchronous up and down movement under the action of the second drive motor 121-2. Only two drive devices are provided in the chamber of the shell 11, which well realizes the active drive of the three fingers. Here, the transmission of the driving force is realized by the engagement of the active gear 124-1 at the lower end of the drive motor with the passive gear 124-2 at the lower end of the lead screw. The specific structure of the lead screw is shown in FIG. Figure 5As shown, it mainly includes a bearing seat 122a, a support frame 122b, a bearing 122c, a screw 122d, a clamping sleeve 122e, a nut rod 122f and a pressing ring 122g. The screw is driven to rotate by a passive gear, thereby converting the rotation of the screw 122d into a linear motion of the nut rod 122f, thereby realizing the up and down linear motion of the screw.

[0073] The structures of the index finger component 22, the middle finger component 23, the little finger component 24 and the ring finger component 25 are further described below. Figure 3 and Figure 6 As shown, the structures of the four fingers include an upper joint 9A and a lower joint 9B. A hinge seat 111 hinged to the index finger assembly 22, the middle finger assembly 23, the little finger assembly 24 and the ring finger assembly 25 is fixed at the upper end of the housing 11. A first hinge hole C1 near the inner lower part and a second hinge hole C2 near the outer upper part are provided on the hinge seat 111. Figure 3 The two hinge holes C1 and C2 are arranged diagonally, and the third hinge hole D1 on the outside and the fourth hinge hole D2 on the inside are respectively provided at the lower end of the upper joint 9A; one end of the lower joint 9B is rotatably connected to the first hinge hole C1 through a rotating shaft 40, and the other end thereof is rotatably connected to the third hinge hole D1 of the upper joint 9A through a rotating shaft 40; the fourth hinge hole D2 of the upper joint 9A is rotatably connected to one end of the connecting rod 30 through a rotating shaft 40, and the other end of the connecting rod 30 is rotatably connected to the second hinge hole C2 through a rotating shaft 40; an arc-shaped long strip hole 9B-1 is formed on the lower joint 9B, such as Figure 7 As shown, the arc-shaped long hole 9B-1 is an arc formed with the first hinge hole C1 as the axis, and a pull shaft 10 is arranged in the arc-shaped long hole 9B-1. The pull shaft 10 is connected to the pull rod 123 through a hinge chain 20. A torsion spring 50 is also arranged on the rotating shaft 40 at the position of the third hinge hole D1, and the two protruding ends of the torsion spring 50 are respectively arranged at the connection points of the upper joint and the lower joint. The hinge chain 20 is driven to move up and down by the pull rod 123 in the driving device. For example, when the hinge chain 20 and the pull shaft 10 are driven to move downward, the lower joint rotates around the rotation axis located in the first hinge hole. At this time, the lower joint drives the upper joint to rotate around the rotation axis located in the second hinge hole. Since the lower joint rotates around the rotation axis in the inner first hinge hole, and the upper joint rotates around the rotation axis in the outer second hinge hole through the connecting rod, since the rotation axes of the connecting rod and the lower joint are different, the rotation radius is also different. In the process of driving the lower joint to rotate, the upper joint will rotate around the rotation axis in the third hinge hole, thereby simulating the downward bending action of the upper joint by a human hand.

[0074] The thumb component 21 is as Figure 8 and Fig. 9As shown, it includes a base 211, a limiting frame 212 and a thumb 213. The limiting frame 212 is arranged on the base 211, and the base 211 is fixedly connected to the shell 11; a first slide groove A is formed on the limiting frame 212, and the lower end of the thumb 213 is connected to the first slide groove A through a pin shaft connector 4, and the thumb 213 moves up and down along the first slide groove A.

[0075] The limiting frame 212 used in the present invention includes a fixed plate 2121 and support blocks 2122 arranged at both ends of the fixed plate 2121. The first slide groove A is formed on the side of the fixed plate 2121. The outer end surface of the fixed plate 2121 is formed with a second slide groove B connected to the first slide groove A. A square slider 2131 is arranged at the lower end of the thumb 213. The square slider 2131 is arranged in the second slide groove B and extends into the first slide groove A. The square slider 2131 is connected to the first slide groove A through a pin connecting member 4 that passes through the first slide groove A. The square slider 2131 is slidably connected to the second slide groove B. The present invention preferably designs the outer end surface of the fixed plate 2121 to be an arc convex outward, and the first slide groove A is an arc slide groove arranged parallel to the outer end surface of the fixed plate 2121. The thumb is provided with a function of rotating along the arc slide groove during the up and down movement, and the arc angle formed by the thumb 213 moving up and down along the first slide groove A is less than or equal to 80 degrees. The arc-shaped slide structure allows the thumb to receive better force when performing pinching actions, such as Fig.10 shown.

[0076] The pin connection member here can be composed of a bolt and a nut. The opening and closing force of the thumb 213 can be adjusted by rotating the nut on the pin connection member, so that the thumb has a suitable damping when moving up and down along the first slide groove A. By manually driving the thumb to move upward along the first slide groove A, the thumb can be stretched forward, which greatly increases the range of action of the thumb.

[0077] In addition, the present invention further increases the left-right rotation function of the limit frame, so that the thumb can pinch the back of the grasped object. Fig.12 shown.

[0078] The present invention preferably further provides a bottom plate 3 on the base 211, the bottom plate 3 is fixed to the base 211 through a fixing shaft 5, a fixing block 6 is provided at each end of the bottom plate 3, the fixing block 6 is rotationally connected to the support blocks 2122 provided at both ends of the limiting frame 212 through a fixing connector 7, the limiting frame 212 rotates left and right along the fixing connector 7, and the rotation angle formed is less than or equal to 90 degrees. The fixing connector 7 here can be a standard structure such as a bolt, by applying a force to the thumb outward, the limiting frame is turned outward, the index finger is bent downward, and then the thumb and the index finger are contacted, so as to realize the back pinching action, and the pinching effect can be achieved by loosening or tightening the fixing connector.

[0079] The fixing shaft 5 used in the present invention is preferably a universal shaft with a spherical end cover 51, and a bolt can also be used. Fig.10 As shown, the rotation center is the center of the fixing shaft 5, and the spherical end cover 51 of the fixing shaft 5 forms a spherical contact with the bottom plate 3 to form an integrated structure.

[0080] like Fig.11 As shown, the rotating wrist 8 is fixed at the lower end of the housing 11. The rotating wrist 8 includes a cylindrical support 81, a rotating body 82 and a circuit board 83. The two ends of the cylindrical support 81 are open. The rotating body 82 is arranged at the opening position of one end of the cylindrical support 81 and forms a relative rotation connection with the inner side surface of the cylindrical support 81. The circuit board 83 is fixed inside the cylindrical support 81. The rotating body 82 is provided with an electric slip ring 84. The electric slip ring 84 includes an upper slip ring 841 and a lower slip ring 842 that are electrically connected. The upper slip ring 841 and the lower slip ring 842 are relatively rotationally connected. The lower slip ring 842 and the circuit board 83 are electrically connected through a connecting wire 85. A connecting plate 86 is also provided at the upper end of the rotating body 82. The lower end of the housing 11 is fixedly connected to the connecting plate 86 through a connecting member.

[0081] When the rotating body 82 rotates, the upper slip ring 841 rotates synchronously with the rotating body 82, the lower slide body 842 and the circuit board 83 remain stationary, and the connecting wire 85 includes a slip ring connecting wire and a circuit board connecting wire. The two remain relatively still after being connected. The rotating wrist 8 can rotate continuously in one direction, exceeding a rotation angle of 360°, and the rotating body can also be rotated at will without causing entanglement of the internal circuits of the cylindrical support. It is easier to use and more convenient to assemble.

[0082] Fig.11 An annular protrusion is formed on the inner side of the upper part of the cylindrical support 81, and an O-shaped rubber pad is respectively arranged between the rotating body 82 and the upper and lower end surfaces of the annular protrusion. The O-shaped rubber pad here can avoid the noise generated when the two rotate relative to each other.

[0083] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A prosthetic hand, comprising a palm component (1) and a finger component (2), wherein the finger component (2) comprises a thumb component (21), an index finger component (22), a middle finger component (23), a little finger component (24) and a ring finger component (25), wherein the palm component (1) comprises a housing (11) and a drive device (12), wherein a chamber is formed in the housing (11), and the drive device (12) is arranged in the chamber and forms a driving connection with the finger component (2) located at the upper end of the housing (11), wherein: The driving device (12) comprises a first driving motor (121-1) and a first lead screw (122-1) connected to the first driving motor (121-1); a driving connection is formed between the first lead screw (122-1) and the index finger assembly (22) for driving the index finger assembly (22) to move up and down; the thumb assembly (21) is a passive thumb assembly arranged on the housing (11), and forms a front opening and closing with the index finger assembly (22); The driving device (12) further comprises a second driving motor (121-2) and a second lead screw (122-2) connected to the second driving motor (121-2), wherein the second lead screw (122-2) is connected to the middle finger assembly (23), the little finger assembly (24) and the ring finger assembly (25) via a pull rod (123) to form a synchronous displacement connection; The pull rod (123) is a three-finger pull rod, an active hinged portion (1231) hinged to the second lead screw (122-2) is provided at the middle portion of the pull rod (123), and three passive hinged portions (1232) are provided on the other side of the pull rod (123) corresponding to the active hinged portion (1231), and the passive hinged portions (1232) are respectively hinged to the middle finger component (23), the little finger component (24) and the ring finger component (25); The index finger assembly (22), the middle finger assembly (23), the little finger assembly (24) and the ring finger assembly (25) each comprise an upper joint (9A) and a lower joint (9B); a hinge seat (111) is fixed at the upper end of the housing (11) and is hingedly connected to each of the index finger assembly (22), the middle finger assembly (23), the little finger assembly (24) and the ring finger assembly (25); a first hinge hole (C1) close to the inner lower portion and a second hinge hole (C2) close to the outer upper portion are provided on the hinge seat (111); and a third hinge hole (D1) on the outer side and a fourth hinge hole (D2) on the inner side are provided at the lower end of the upper joint (9A); One end of the lower joint (9B) is rotationally connected to the first hinge hole (C1) via a rotating shaft (40), and the other end is rotationally connected to the third hinge hole (D1) of the upper joint (9A) via a rotating shaft (40); the fourth hinge hole (D2) of the upper joint (9A) is rotationally connected to one end of the connecting rod (30) via a rotating shaft (40), and the other end of the connecting rod (30) is rotationally connected to the second hinge hole (C2) via a rotating shaft (40); an arc-shaped long hole (9B-1) is formed on the lower joint (9B), and the arc-shaped long hole (9B-1) is an arc formed with the first hinge hole (C1) as the axis. A pulling shaft (10) is arranged in the arc-shaped long hole (9B-1), and the pulling shaft (10) is connected to the pulling rod (123) via a hinge chain (20). A torsion spring (50) is also arranged on the rotating shaft (40) at the position of the third hinge hole (D1); A rotating arm (8) is also fixed at the lower end of the shell (11), and the rotating arm (8) comprises a cylindrical support (81), a rotating body (82) and a circuit board (83). Both ends of the cylindrical support (81) are open, and the rotating body (82) is arranged at an open position at one end of the cylindrical support (81) and forms a relative rotation connection with the inner side surface of the cylindrical support (81). The circuit board (83) is fixed inside the cylindrical support (81). An electric slip ring (84) is provided on the rotating body (82), and the electric slip ring (84) comprises an upper slip ring (841) and a lower slip ring (842) which are electrically connected. The upper slip ring (841) and the lower slip ring (842) are relatively rotationally connected, and the lower slip ring (842) and the circuit board (83) are electrically connected via a connecting wire (85); The thumb assembly (21) comprises a base (211), a limiting frame (212) and a thumb (213); the limiting frame (212) is arranged on the base (211); the base (211) is fixedly connected to the housing (11); a first slide groove (A) is formed on the limiting frame (212); the lower end of the thumb (213) is connected to the first slide groove (A) through a pin connecting member (4); and the thumb (213) moves up and down along the first slide groove (A).

2. The prosthetic hand according to claim 1, characterized in that: The limiting frame (212) comprises a fixing plate (2121) and support blocks (2122) arranged at both ends of the fixing plate (2121); the first slide groove (A) is formed on the side of the fixing plate (2121); the outer end surface of the fixing plate (2121) is formed with a second slide groove (B) connected to the first slide groove (A); a square slider (2131) is arranged at the lower end of the thumb (213); the square slider (2131) is arranged in the second slide groove (B) and extends into the first slide groove (A); the square slider (2131) is connected to the first slide groove (A) by a pin connecting member (4) passing through the first slide groove (A); the square slider (2131) is slidably connected to the second slide groove (B).

3. The prosthetic hand according to claim 2, characterized in that: The outer end surface of the fixing plate (2121) is in the shape of an arc that bulges outwards, and the first sliding groove (A) is an arc-shaped sliding groove that is arranged parallel to the outer end surface of the fixing plate (2121).

4. The prosthetic hand according to claim 3, characterized in that: A bottom plate (3) is also provided on the base (211), and the bottom plate (3) is fixed to the base (211) via a fixing shaft (5). A fixing block (6) is provided at each end of the bottom plate (3), and the fixing block (6) is rotatably connected to a support block (2122) provided at each end of the limiting frame (212) via a fixing connection piece (7). The limiting frame (212) rotates left and right along the fixing connection piece (7).

5. The prosthetic hand according to claim 4, characterized in that: The fixing rotating shaft (5) is a universal shaft with a spherical end cover (51), and the base plate (3) is in contact with the spherical end cover (51) of the fixing rotating shaft (5).

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