CN112318548B - Mechanical arm - Google Patents

Abstract

The invention discloses a mechanical holding arm which comprises a plurality of joint units connected front and back, wherein each joint unit comprises a shell, a spherical head and a locking mechanism, wherein the spherical head and the locking mechanism are coaxially arranged in the shell. According to the invention, any length combination of the mechanical holding arm is realized through the assembly relation of the spherical head and the shell, and the pressure is applied to the spherical head through the position relation of the conical top block and the expansion block, so that the friction force between the spherical head and the inner wall of the shell is regulated, and the mechanical holding arm is controlled to have a free state, a damping state and a locking state, so that the mechanical holding arm is convenient to accurately and freely regulate. The whole structure of the mechanical arm is simple to set, is convenient to connect and use, and effectively reduces the cost requirement of fixing the joint.

Description

A mechanical arm

Technical Field

The present invention belongs to the technical field of medical equipment, and in particular relates to a mechanical arm holding a device.

Background technique

With the rapid development of robots, various surgical instrument fixation devices have emerged, and among them, the use of serpentine joints to fix surgical instruments has become more and more common. Serpentine joints can achieve plane torsion and spatial torsion, and can adjust surgical instruments over a wide range and at a wide angle according to the doctor's requirements to meet surgical requirements, reduce surgical manpower requirements, and improve surgical reliability and safety.

However, the serpentine joints currently used in medical devices have the disadvantages of complex structure, many parts and complicated assembly. For example, the US patent with the announcement number of US 6817974 B2 proposes a serpentine joint, in which the joints are connected by a short connecting rod-like structure, which can realize spatial torsion motion through different arrangements, but in the bending and torsion process, there are disadvantages of low motion accuracy, complex structure and high cost.

Summary of the invention

The purpose of this application is to provide a mechanical arm that has a serpentine fixed joint with high motion accuracy, simple structure and low cost.

In order to achieve the above purpose, the technical solution of this application is as follows:

A mechanical arm, comprising a plurality of joint units connected front and back, wherein the joint units comprise a shell, a spherical head coaxially arranged inside the shell, and a locking mechanism;

The shell is in the shape of a hollow cylinder, and the bottom of the shell is inwardly concave to form a hemispherical groove. The top of the shell is provided with a rotating port connected to the hollow interior, and the outer wall of the shell near the rotating port is bent inward so that the top of the hollow interior forms a hemispherical space;

The spherical head comprises a rotating sphere with a hollow interior and an open bottom, the outer diameter of the rotating sphere matches the diameter of the hemispherical space, and the rotating sphere is located in the hemispherical space, a convex rod is provided on the top of the rotating sphere, and the convex rod is fixed to the hemispherical groove of the shell of the previous joint unit after extending out of the hemispherical space from the rotating mouth, and the diameter of the rotating mouth is larger than the rod diameter of the convex rod;

The locking mechanism includes a conical top block and multiple expansion blocks. The multiple expansion blocks are movably assembled inside the spherical head. The multiple expansion blocks are combined to form an expansion sphere with a conical hollow hole inside. The conical top block matches the conical hollow hole of the expansion sphere after passing through the bottom opening of the spherical head. A motor is used to control the conical top block to extend into the expansion sphere at different depths so that the robotic arm has a free state, a damping state and a locked state.

Preferably, the shell comprises an upper shell and a lower shell, the upper shell is sleeved on the outer surface of the lower shell, the hemispherical groove is arranged at the bottom of the lower shell, and the rotating port and the hemispherical space are arranged at the top of the upper shell.

Preferably, the rotating sphere includes an upper hemisphere and a lower hemisphere, the convex rod is fixed to the upper hemisphere, an opening is provided at the bottom of the lower hemisphere, and the interiors of the upper hemisphere and the lower hemisphere are both hollow.

Preferably, the upper bottom surface of the conical hollow hole inside the expanded sphere is smaller than the lower bottom surface, and the bottom opening of the spherical head is larger than the lower bottom surface of the conical hollow hole and smaller than the diameter of the expanded sphere.

Preferably, the locking mechanism further comprises a screw motor, the conical top block is a conical screw nut, the conical screw nut cooperates with the screw of the screw motor and moves up and down following the rotation of the screw motor.

Preferably, an elastic component is provided between the motor body of the lead screw motor and the tapered lead screw nut.

Preferably, the mechanical arm further comprises a supporting ring support, the supporting ring support is fixed to the shell, the inner surface of the supporting ring support is an arc surface, and the arc surface abuts against the spherical head.

Preferably, the number of the expansion blocks is greater than or equal to 3.

Preferably, in the front and rear joint units, the protruding rod of the rear joint unit and the hemispherical groove of the front joint unit can be detachably assembled, and after the front and rear joint units are assembled, part of the inner surface of the hemispherical groove of the front joint unit is against the outer surface of the shell of the rear joint unit.

Preferably, the robotic arm comprises at least two joint units.

The mechanical arm proposed in this application realizes any length combination of the mechanical arm through the assembly relationship between the spherical head and the shell, and applies pressure to the spherical head through the position relationship between the conical top block and the expansion block, and adjusts the friction between the spherical head and the inner wall of the shell, thereby controlling the mechanical arm to have a free state, a damping state and a locked state, which facilitates the precise and free adjustment of the mechanical arm. The overall structure of the mechanical arm is simple to set and easy to connect and use, effectively reducing the cost of fixing the joint.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of the mechanical arm of the present application;

FIG2 is a partial exploded schematic diagram of the armed mechanical arm of the present application;

FIG3 is an exploded view of the joint unit of the present application after removing the outer shell;

Fig. 4 is a cross-sectional view taken along the A-A plane in Fig. 1;

FIG5 is a schematic structural diagram of a joint unit in FIG4 ;

FIG6 is a schematic structural diagram of the outer shell portion in FIG5 ;

FIG. 7 is a schematic diagram of the structure of FIG. 5 with the outer shell portion removed.

In the figure: 1, joint unit; 2, upper shell; 201, rotating mouth; 202, hemispherical space; 3, upper hemisphere; 4, expansion block; 5, conical top block; 6, lower hemisphere; 7, support ring bracket; 8, screw motor; 9, screw; 10, lower shell; 1001, hemispherical groove; 11, protruding rod; 12, elastic component.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

As shown in FIG. 1 , in one embodiment, a device-holding robotic arm is provided. The device-holding robotic arm (eg, surgical instrument) includes a plurality of joint units 1 connected front to back.

As shown in FIGS. 2 to 7 , each joint unit 1 includes a housing, a spherical head coaxially arranged inside the housing, and a locking mechanism.

The shell is a hollow cylindrical body, and the bottom of the shell is concave inward to form a hemispherical groove 1001. The top of the shell is provided with a rotating port 201 connected to the hollow interior. The outer wall of the shell close to the rotating port 201 is bent inward so that the top of the hollow interior forms a hemispherical space 202.

The spherical head includes a rotating sphere with a hollow interior and an open bottom. The outer diameter of the rotating sphere matches the diameter of the hemispherical space 202, and the rotating sphere is located in the hemispherical space 202. A convex rod 11 is provided on the top of the rotating sphere. The convex rod 11 extends out of the hemispherical space 202 from the rotating mouth 201 and is fixed to the hemispherical groove 1001 of the shell of the previous joint unit. The diameter of the rotating mouth 201 is larger than the rod diameter of the convex rod 11 to meet the large range of rotation of the convex rod 11.

The locking mechanism includes a conical top block 5 and a plurality of expansion blocks 4. The plurality of expansion blocks 4 are movably assembled inside the spherical head. The plurality of expansion blocks 4 are combined to form an expansion sphere with a conical hollow hole inside. The conical top block 5 passes through the bottom opening of the spherical head and cooperates with the conical hollow hole of the expansion sphere. A motor is used to control the conical top block 5 to extend into the expansion sphere at different depths so that the robotic arm has a free state, a damping state and a locked state.

In this embodiment, when the conical top block 5 is not inserted or the insertion depth is small, the expansion sphere is not subjected to pressure. At this time, the multiple expansion blocks 4 are in a natural unexpanded state. The expansion blocks 4 have no force or very small force on the inner wall of the rotating sphere. The friction between the outer surface of the rotating sphere and the inner wall of the shell is small. The outside world can apply force to easily change the position of the protruding rod 11 in the rotating mouth 201 and change the movement state of the armed robotic arm. At this time, the armed robotic arm is in a free state.

When the conical top block 5 extends into the conical hollow hole to a certain depth, the expansion sphere is stretched open by force, and the multiple expansion blocks 4 move away from each other and resist the inner surface of the rotating sphere. After the rotating sphere is subjected to force, the outer surface rests against the inner wall of the shell. The friction between the inner wall of the shell and the outer surface of the rotating sphere makes it relatively difficult for the rotating sphere to rotate. A small force applied from the outside cannot easily change the position of the convex rod in the rotating mouth. At this time, the mechanical arm is in a damping state.

When the conical top block 5 is inserted into the conical hollow hole to a sufficient depth, the expansion sphere is stretched to the maximum extent by the force, and the multiple expansion blocks 4 move away from each other and resist the inner surface of the rotating sphere. After the rotating sphere is subjected to force, the outer surface of the rotating sphere resists against the inner wall of the shell. Since the force exerted by the expansion blocks on the rotating sphere is relatively large at this time, a large friction force is generated between the inner wall of the shell and the outer surface of the rotating sphere. This friction force makes it impossible to change the position of the convex rod in the rotating mouth even if a large force is applied from the outside. At this time, the mechanical arm is in a locked state.

It should be noted that the depth of the conical top block 5 inserted into the conical hollow hole in the free state, damping state and locking state can be set according to needs, that is, different insertion depths can bring different motion states, but the depth limits corresponding to each specific state can be divided according to the actual working requirements of the robotic arm.

The robotic arm as a whole uses the friction force on the surface of an object to adjust the motion state, overcoming the problem of jitter displacement after locking in the existing pneumatic locking method, and bringing higher motion adjustment accuracy; and the free rotation of the convex rod in the rotating mouth makes the robotic arm a serpentine joint, which can realize adjustment in any direction and angle, and is easy to use.

In order to facilitate the later maintenance of the joint unit, in one embodiment, the shell includes an upper shell 2 and a lower shell 10, the upper shell 2 is sleeved on the outer surface of the lower shell 10, the hemispherical groove 1001 is arranged at the bottom of the lower shell 10, and the rotating mouth 201 and the hemispherical space 202 are arranged at the top of the upper shell 2.

Specifically, in order to improve the aesthetics of the joint unit, it is preferred that both the upper shell 2 and the lower shell 10 are hollow cylindrical structures, and the radius of the upper shell 2 and the lower shell 10 is the same, so as to achieve a seamless connection between the upper and lower shells. The wall thickness of the upper shell 2 is smaller than that of the lower shell 10, and the wall thickness of the top of the lower shell 10 is thinned to form a nesting step, so that the upper shell 2 can be directly installed on the nesting step, and the upper shell 2 and the lower shell 10 are fastened by screws 9 that penetrate the upper shell 2 and abut against the outer wall of the lower shell 10.

Since it is difficult to directly install the expansion block into the hollow rotating sphere, in one embodiment, the rotating sphere includes an upper hemisphere 3 and a lower hemisphere 6. The division of the rotating sphere not only facilitates the installation of the expansion block but also does not affect the rotation of the spherical head.

The convex rod 11 is fixed to the upper hemisphere 3, and an opening is provided at the bottom of the lower hemisphere 6 as the bottom opening of the spherical head. The interiors of the upper hemisphere 3 and the lower hemisphere 6 are both hollow, forming a spherical head with a hollow interior.

It is easy to understand that in order for the conical top block 5 to be inserted through the bottom opening of the spherical head, the upper bottom surface of the conical hollow hole inside the main expansion sphere is smaller than the lower bottom surface, and the bottom opening of the spherical head is larger than the lower bottom surface of the conical hollow hole and smaller than the diameter of the expansion sphere (in the unexpanded state).

Since the expansion block 4 and the conical top block 5 inside the spherical head do not follow the rotation during the rotation of the spherical head, it is preferred to set the bottom opening of the spherical head larger than the lower bottom surface of the conical hollow hole to reserve enough rotation space for the rotating sphere. In addition, the bottom opening of the spherical head is preferably smaller than the diameter of the expansion sphere to prevent the expansion block 4 from falling out of the spherical head in the unexpanded state.

In the movement of driving the conical top block 5 to extend into or out of the conical hollow hole of the expansion sphere, the telescopic rod can directly provide a force for the conical top block 5, so that the expansion sphere expands when the telescopic rod is extended, and the expansion sphere returns to a natural unexpanded state when the telescopic rod is contracted.

Of course, the conical top block 5 can also be driven by a motor, for example, the locking mechanism also includes a screw motor 8, the conical top block 5 is a conical screw nut, the conical screw nut cooperates with the screw of the screw motor 8, and moves up and down following the rotation of the screw motor. Compared with the driving method of the telescopic rod, the driving method using the screw motor 8 has better stability and higher movement accuracy.

In order to further reduce the vibration caused by the rotation of the screw motor 8, an elastic component 12 is provided between the motor body of the screw motor 8 and the conical screw nut. The elastic component 12 can not only absorb part of the vibration, thereby improving the overall motion accuracy of the mechanical arm, but also provide support for the expansion block 4 after the conical top block 5 is withdrawn.

Since there is no additional restriction structure between the upper hemisphere 3 and the lower hemisphere 6 in the spherical head, there is no additional restriction structure between the upper hemisphere 3 and the lower hemisphere 6 and the shell, there is no additional restriction structure between the expansion block 4 and the upper hemisphere 3 and the lower hemisphere 6, and there is no additional restriction structure between the conical top block 5 and the expansion block 4, so the above components do not have a good support point. Therefore, in one embodiment, the mechanical arm also includes a support ring 7, which is fixed to the shell, and the inner surface of the support ring 7 is a curved surface, and the curved surface is against the spherical head.

The support ring 7 is an annular structure. In order to improve the supporting force and not affect the rotation of the spherical head, the inner surface of the support ring 7 is set to be an arc surface, and the radius of the circle where the arc surface is located is greater than the radius of the rotating sphere.

It should be noted that, in other embodiments, the inner surface of the support ring 7 may be a whole arc surface, or a part of the inner surface may be a arc surface on the premise of satisfying the support range.

In this embodiment, the state change of the robotic arm is achieved by the expansion of the expansion blocks. In order to ensure a better state adjustment effect, in this embodiment, it is preferred to set the expansion blocks to be greater than or equal to 3, that is, it can be 3, 4, 5, etc.

For the mechanical arm of the present embodiment, it includes at least two joint units 1 to achieve direction and angle adjustment. It is easy to understand that the adjustment direction and angle of each joint unit are limited by the rotation range of the protruding rod 11 in the rotation opening 201, but when there are enough joint units 1 connected, the rotation range of one joint unit 1 will be cumulatively enlarged, and finally a mechanical arm that can be adjusted in any direction and angle can be obtained.

In the connection of multiple joint units 1, in the front and rear joint units 1, the convex rod 11 of the rear joint unit 1 and the hemispherical groove 1001 of the front joint unit 1 can be detachably assembled, and after the front and rear joint units are assembled, part of the inner surface of the hemispherical groove 1001 of the front joint unit abuts against the outer surface of the shell of the rear joint unit 1. This not only ensures the beauty of the overall appearance of the mechanical arm, but also the shell of the rear joint unit 1 provides support and limit for the rotation of the front joint unit 1.

In the present application, the terms "top", "bottom", "upper", "lower", "inner", "outer", "axial", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in certain drawings, or based on the spatial posture of the product under normal use. Of course, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the position or component referred to must have a specific orientation, a specific structure and operation, and therefore cannot be understood as a limitation on the present application.

The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims (7)

1. The mechanical arm comprises a plurality of joint units which are connected front and back, and is characterized by comprising a shell, a spherical head and a locking mechanism, wherein the spherical head and the locking mechanism are coaxially arranged in the shell;

The shell is in a cylindrical shape with a hollow inside, the bottom of the shell is inwards recessed to form a hemispherical groove, the top of the shell is provided with a rotating opening communicated with the hollow inside, and the outer wall of one side of the shell, which is close to the rotating opening, is inwards bent to enable the top of the hollow inside to form a hemispherical space;

The spherical head comprises a rotary sphere with a hollow inside and an open bottom, the outer diameter of the rotary sphere is matched with the diameter of the hemispherical space, the rotary sphere is positioned in the hemispherical space, a convex rod is arranged at the top of the rotary sphere, the convex rod is fixed with a hemispherical groove of the shell of the previous joint unit after extending out of the hemispherical space from a rotary opening, and the caliber of the rotary opening is larger than the rod diameter of the convex rod;

The locking mechanism comprises a conical jacking block and a plurality of expansion blocks, the expansion blocks are movably assembled in the spherical head, the expansion blocks are combined to form an expansion sphere with a conical hollow hole inside, the conical jacking block is matched with the conical hollow hole of the expansion sphere after passing through the bottom opening of the spherical head, the upper bottom surface of the conical hollow hole in the expansion sphere is smaller than the lower bottom surface, and the bottom opening of the spherical head is larger than the lower bottom surface of the conical hollow hole and smaller than the diameter of the expansion sphere;

The locking mechanism further comprises a screw motor, the conical ejector block is a conical screw nut, the conical screw nut is matched with a screw of the screw motor and moves up and down along with rotation of the screw motor, an elastic part is arranged between a motor body of the screw motor and the conical screw nut, and the motor is used for controlling the conical ejector block to extend into different depths of an expansion sphere so that the mechanical arm has a free state, a damping state and a locking state.

2. The mechanical arm of claim 1, wherein the housing comprises an upper housing and a lower housing, the upper housing is sleeved on the outer surface of the lower housing, the hemispherical groove is arranged at the bottom of the lower housing, and the rotation opening and the hemispherical space are arranged at the top of the upper housing.

3. The mechanical arm of claim 1, wherein the rotary sphere comprises an upper hemisphere and a lower hemisphere, the protruding rod is fixed with the upper hemisphere, an opening is arranged at the bottom of the lower hemisphere, and the interiors of the upper hemisphere and the lower hemisphere are hollow.

4. The mechanical arm of claim 1, further comprising a support ring support, wherein the support ring support is fixed to the housing, and wherein the inner surface of the support ring support is a cambered surface and abuts against the spherical head through the cambered surface.

5. The mechanical arm of claim 1, wherein the expansion block is greater than or equal to 3 blocks.

6. The mechanical arm according to claim 1, wherein the protruding rod of the latter joint unit is detachably assembled with the hemispherical groove of the former joint unit, and after the former joint unit is assembled with the latter joint unit, part of the inner surface of the hemispherical groove of the former joint unit is abutted against the outer surface of the housing of the latter joint unit.

7. The holding arm of claim 1, wherein the holding arm comprises at least 2 joint units.