Snake bone pair, flexible joint assembly and surgical operation arm

Abstract

The utility model discloses a snake bone pair, a flexible joint assembly and a surgical operation arm. The snake bone pair, the flexible joint assembly and the surgical operation arm aim to solve the problem that uncertain dislocation sliding occurs between two bone joints in the bending process of the snake bone pair. The snake bone pair comprises two bone joints, a supporting structure, a first elastic rod and a second elastic rod. Each joint can rotate based on the corresponding rotating shaft, and the supporting structure is arranged between the two joints parallel to the rotating shafts so that the distance between the two rotating shafts can be constant. The two elastic rods are both connected between the two joints, and orthographic projections of the two elastic rods on the normal plane of the rotating shaft are in a cross symmetry state. Each joint comprises a first constraint cambered surface and a second constraint cambered surface which are equal in radius and coincide in central axis, the first elastic rod is attached to the first constraint cambered surface, and the second elastic rod is attached to the second constraint cambered surface; orthographic projections of the two constraint cambered surfaces on the same joint on the normal plane of the rotating shaft are symmetrical based on a first plane, and the first plane coincides with the central axis and the rotating shaft. Therefore, the bending precision and the load deformation resistance of the snake bone can be improved.

Description

Technical Field

[0001] This application relates to the technical field of medical devices, and more specifically, to a snake bone pair, a flexible joint assembly, and a surgical operating arm. Background Technology

[0002] Snake-bone pairs are self-bending components widely used in the medical device field. Operators can control the insertion and orientation of the distal end of the surgical arm into the body by bending at least one segment of the snake-bone pair, thereby enabling observation and surgical procedures at designated locations. Snake-bone pairs typically consist of multiple segments, which can rotate in coordination to achieve the self-bending function of the pair.

[0003] In related technologies, although the snake-bone pair can achieve bending at a specified angle by pulling back and releasing the drive cables threaded between each segment, the relative rotation state between the segments is uncertain. This makes it difficult to ensure consistent cable retraction or maintain a balanced lever arm for the drive cables on both sides of the snake-bone pair during bending. The drive cables are prone to deformation or even damage, thus affecting the lifespan of the snake-bone pair and the surgical arm. Furthermore, the uncertain relative rotation state between the segments prevents the snake-bone pair from having a unique shape at a specified bending angle. When any segment of the snake-bone pair is subjected to external force, the pair is highly susceptible to deformation, introducing uncertainties and risks to the surgical procedure and reducing the reliability of the snake-bone pair and surgical arm when used in surgical operations. Utility Model Content

[0004] The purpose of this application is to provide a snake bone pair, a flexible joint assembly, and a surgical operating arm, which can alleviate the technical problem of uncertain misalignment and slippage between the two joints during the bending process of the snake bone pair, and improve the bending accuracy and resistance to load deformation of the snake bone pair.

[0005] The embodiments of this application are implemented as follows:

[0006] In a first aspect, embodiments of this application provide a snake-bone pair, comprising two segments, each capable of rotating based on its own axis of rotation. The snake-bone pair further includes a support structure, a first elastic rod, and a second elastic rod. The support structure is disposed between the two segments with parallel axes of rotation to ensure a constant distance between the two axes of rotation of the same snake-bone pair. The first and second elastic rods are both connected between the two segments, and their orthographic projections onto the normal plane of the rotation axis are cross-symmetrical. Each segment includes a first constraint arc surface and a second constraint arc surface with equal radii and coincident central axes. The first elastic rod is in contact with the first constraint arc surface, and the second elastic rod is in contact with the second constraint arc surface. The orthographic projections of the first and second constraint arc surfaces on the same segment onto the normal plane of the rotation axis are symmetrical based on a first plane, which coincides with the central axis and the rotation axis.

[0007] In the above technical solution, the two joints are rotatably connected by a support structure, which can maintain a constant distance between the two rotating axes. With the rotating axes parallel to each other and the distance constant, the first and second elastic rods are arranged in a cross-symmetrical pattern, and both elastic rods are attached to the constraint arc surface on each joint. This allows the two elastic rods to apply equal constraint forces to the constraint arc surface and each joint during the bending process of the snake bone pair and when the snake bone pair is at rest. This enables the snake bone pair to achieve a symmetrical motion configuration, with a unique shape at a specified bending angle, reducing the probability of misalignment and slippage between the joints, and improving the bending accuracy and load deformation resistance of the snake bone pair. The two constraint arc surfaces are symmetrical based on the first plane, which makes the force on the joints more uniform and balanced in all directions, improving the stability and consistency of joint rotation and the overall stability of the snake bone pair structure. Building upon this, the elastic deformation capability of the elastic rod reduces the output force required for the drive cable to tighten and drive the snake pair to bend. The elastic rod also provides auxiliary force during the snake pair's return process based on its restoring deformation characteristics, similarly reducing the output force required for the drive cable to drive the snake pair back into position. Furthermore, the support structure can distribute the pressure load generated by the interaction of the joints during drive cable tightening, thereby reducing joint wear and extending the service life of the joints and the snake pair.

[0008] In some embodiments, when the snake bone pair is in a straight state, the two segments face each other and their adjacent end faces are parallel; the first elastic rod is tangent to the first constraint arc surface on the two segments, and the second elastic rod is tangent to the second constraint arc surface on the two segments. In the above technical solution, the design of the elastic rod being tangent to the constraint arc surface reduces the friction between them, thereby reducing segment wear and extending the service life of the snake bone pair; the design of the elastic rod being tangent to the constraint arc surface also simplifies the manufacturing process of the segments and the assembly process of the snake bone pair, resulting in lower manufacturing costs.

[0009] In some embodiments, when the snake-bone pair is in a straight state, the two segments face each other and their adjacent end faces are parallel; a first elastic rod wraps around a first constraint arc surface of each segment, and a second elastic rod wraps around a second constraint arc surface of each segment. In the above technical solution, the design of the elastic rod wrapping around the constraint arc surface increases the contact area between the elastic rod and the constraint arc surface, making the force transmission more uniform and stable, thereby improving the bending stability and shape maintenance stability of the snake-bone pair, and enhancing the load-bearing capacity and structural strength of the snake-bone pair.

[0010] In some embodiments, the distance between the two rotating shafts is the center distance of the snake bone pair, and the radii of both the first and second constraint arc surfaces do not exceed half of the center distance. In the above technical solution, the radius of the constraint arc surfaces not exceeding half of the center distance helps reduce the processing difficulty of the bone joints and the assembly difficulty of the snake bone pair, thereby improving the smoothness of the snake bone pair's bending.

[0011] In some embodiments, on the same joint, a first constraint arc surface and a second constraint arc surface are connected or partially overlapped to form a double constraint arc surface. In the above technical solution, the first constraint arc surface and the second constraint arc surface are connected or partially overlapped to form a semi-circular double constraint arc surface, which makes the structure of the joint simpler and more compact, and more conducive to the processing and assembly of snake bone pairs.

[0012] In some embodiments, the snake-bone pair includes at least one pair of adjacent first and second elastic rods. Each of the adjacent edges of the first and second elastic rods is provided with a clearance groove. The first and second elastic rods are arranged intersectingly through the clearance grooves and are independent of each other. In the above technical solution, the adjacent first and second elastic rods can reduce motion interference through the design of the clearance grooves. Each elastic rod can be bent and twisted independently, thereby improving the flexibility, smoothness, reliability, and stability of the snake-bone pair in bending. Furthermore, the installation and disassembly process of the first and second elastic rods is simpler, and the clearance grooves save space between the two joints, making the elastic rod layout more reasonable and compact.

[0013] In some embodiments, in the snake-bone pair, the adjacent end faces of the two segments are the first end faces; each end of the rotating shaft is provided with a first elastic rod and a second elastic rod. In the above technical solution, the provision of a first elastic rod and a second elastic rod at each end of the rotating shaft gives the snake-bone pair good symmetry, which is beneficial for the uniform distribution of load, reduces local stress concentration, and improves the stability and load-bearing capacity of the overall structure of the snake-bone pair.

[0014] In some embodiments, in the snake-bone pair, the surfaces of two segments facing each other and adjacent to each other are the first end faces; a first elastic rod is provided at one end of the rotating shaft, and a second elastic rod is provided at the other end of the rotating shaft. In the above technical solution, an elastic rod is provided at each end of the rotating shaft, which makes the snake-bone pair have good symmetry, thereby facilitating the uniform distribution of load, reducing local stress concentration, and improving the stability and load-bearing capacity of the overall structure of the snake-bone pair.

[0015] Secondly, embodiments of this application provide a flexible joint assembly, which includes at least two snake-bone pairs as provided in any embodiment of the first aspect of this application, at least two drive cables, and at least two constraint cables. The at least two snake-bone pairs extend in the same direction along their rotation axes; each drive cable and each constraint cable extends and passes through each snake-bone pair, and the connection positions of the drive cables and constraint cables at each joint are symmetrical based on the rotation axis; one end of each drive cable is fixedly connected to the most distal joint in the flexible joint assembly; between two snake-bone pairs that extend in the same direction and are most adjacent, the connection position of each constraint cable to the nearest snake-bone pair is a first connection position, and the connection position of each constraint cable to the most distal snake-bone pair is a second connection position. The first connection position is shifted by 180° from the second connection position based on the central axis of the flexible joint assembly. In the above technical solution, the connection position of the drive cable on each joint is based on the axis of rotation symmetry, which enables the drive cables on both sides of the axis of rotation of the snake bone pair to achieve consistent extension and retraction and lever arm balance during the bending process of the snake bone pair; the 180° displacement arrangement of the constraint cable makes the two snake bone pairs that are closest in position and have the same bending direction have a fixed bending angle when the flexible joint component is deflected as a whole, that is, the flexible joint component has a unique shape under a specified deflection angle. The embodiments of this application improve the load deformation resistance of the flexible joint component.

[0016] Thirdly, embodiments of this application provide a surgical operating arm, which includes at least one flexible joint component provided in any embodiment of the second aspect of this application. In the above technical solutions, the surgical operating arm has the same technical effects as the aforementioned flexible joint component.

[0017] The advantages of this application compared to the prior art are:

[0018] This application addresses the problem of uncertain misalignment and slippage between joints during the bending process of a snake-bone pair. When the two joints rotate relative to each other, a flexible traction body arranged in a cross-symmetrical projection applies the same constraint force to both joints, enabling the snake-bone pair to achieve a symmetrical motion configuration during bending and possessing a unique shape at a specified bending angle. This reduces the probability of misalignment and slippage between joints, ultimately improving the bending accuracy and resistance to load deformation of the snake-bone pair. Furthermore, the adjacent first and second elastic rods, through the design of clearance grooves, reduce motion interference and improve the bending flexibility of the snake-bone pair. The design of the elastic rods being tangent to the constraint arc surface reduces friction between them, simplifying the manufacturing of the joints and the assembly process of the snake-bone pair. The design of the elastic rods wrapping around the constraint arc surface improves the load-bearing capacity and structural strength of the snake-bone pair, further enhancing the bending stability and shape maintenance stability of the snake-bone pair. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 The present application provides schematic diagrams illustrating the structure of a surgical robot according to some embodiments.

[0021] Figure 2 This is a schematic diagram of the overall structure of the surgical arm shown in some embodiments of this application;

[0022] Figure 3 This is a schematic diagram of the overall structure of a flexible joint component shown in some embodiments of this application;

[0023] Figure 4 This is a schematic diagram of the overall structure of the second flexible joint assembly shown in some embodiments of this application;

[0024] Figure 5 This is a schematic diagram of the constraint cable layout of the second flexible joint assembly shown in some embodiments of this application;

[0025] Figure 6 This is a schematic diagram of the overall structure of the snake bone pair shown in some embodiments of this application;

[0026] Figure 7 This is a schematic diagram of the explosion of a snake bone pair shown in some embodiments of this application;

[0027] Figure 8 This is an exploded schematic diagram of a snake bone pair shown in some other embodiments of this application;

[0028] Figure 9 This is a front view schematic diagram of a snake bone pair in a flat state, as shown in some embodiments of this application;

[0029] Figure 10 This is a front view schematic diagram of a snake bone pair in a 90-degree bent state, as shown in some embodiments of this application;

[0030] Figure 11 This is a schematic diagram illustrating the geometric principle of the symmetrical motion configuration of the snake bone pair shown in some embodiments of this application.

[0031] Icons: 1-Surgical robot; 2-Surgical arm; 3-Flexible joint component; 4-Snake bone pair; 5-Joint; 21-Tool head; 22-Instrument box; 23-Straight instrument tube; 30-Flexible joint assembly; 31-First flexible joint assembly; 32-Second flexible joint assembly; 33-Drive cable; 34-Constraint cable; 340-Connection position; 341-First connection position; 342-Second connection position; 35-Connecting tube; 401-First snake bone pair; 402-Second snake bone pair; 403-Third snake bone pair; 404-Fourth snake bone pair; 41-Supporting structure Structure; 42-Circular arc top unit; 420-Circular arc top surface; 421-Side guard; 43-Connecting pin assembly; 431-Connecting pin; 4311-Connecting pin shaft; 4312-Connecting rod; 432-Anti-detachment component; 50-Rotating shaft; 500-First plane; 51-Bone base; 510-First end face; 511-Rope hole; 512-Limiting inclined surface; 52-Elastic rod; 520-Relief groove; 521-First elastic rod; 522-Second elastic rod; 53-Constraint arc surface; 531-First constraint arc surface; 532-Second constraint arc surface; A-Rotating shaft extension direction. Detailed Implementation

[0032] The terms “first,” “second,” “third,” etc., are used only for distinguishing descriptions and do not indicate a sequence number, nor should they be interpreted as indicating or implying relative importance.

[0033] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of this application, it should be noted that the terms "inner", "outer", "left", "right", "upper", "lower", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0035] In the description of this application, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” shall be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a mechanical connection or an electrical connection; as a direct connection or an indirect connection through an intermediate medium; or as a connection within two components.

[0036] The technical solution of this application will now be described in detail with reference to the accompanying drawings.

[0037] Surgical robots, as an important research technology in the field of medical devices, are widely used in surgical procedures, assisting surgeons in performing various types of minimally invasive and non-invasive surgeries. Among them, surgical robots with flexible joint components or snake-like skeletons are specially designed robots that can operate in confined spaces and perform complex bending or rotating movements inside the human body. Compared with traditional rigid surgical instruments, this type of surgical robot has many advantages. Using this type of surgical robot to perform surgery can not only improve the precision of surgical operations, but also reduce damage to surrounding tissues at the surgical site, shorten recovery time, and reduce the risk of complications.

[0038] Snake-bone joints are biomimetic joint structures used to create instruments that can bend and twist to reach areas inside the body that are difficult to access with ordinary tools. For example, in endoscopic surgery, surgical instruments with snake-bone joints can help surgeons more accurately locate lesions and perform more precise manipulations. While snake-bone joints can bend by pulling back and releasing drive cables threaded between the joints, the relative rotational state between the joints is uncertain. The snake-bone joint cannot maintain a unique shape at a specified bending angle, and it is prone to deformation under external forces, affecting the reliability and safety of surgical procedures. Therefore, the medical device field urgently needs a new type of snake-bone joint that can maintain a fixed shape while achieving a specified bending angle, thereby further improving the bending accuracy, resistance to load deformation, and reliability of surgical procedures.

[0039] Based on the above considerations, this application provides a snake-bone pair, including two joints, a support structure, and at least one pair of elastic rods projected symmetrically along the extension direction of the rotation axis, each elastic rod being in contact with a constraint arc surface. Thus, during rotation and at rest, the two joints are always subject to the constraint force of the two elastic rods while the support structure maintains parallelism of the rotation axis and a constant distance between them. The snake-bone pair can achieve a symmetrical motion configuration during bending and has a unique shape at a specified bending angle. This application reduces the probability of uncertain rotation or misalignment between the joints, improves the bending accuracy and load deformation resistance of the snake-bone pair, and, based on the elastic deformation characteristics of the elastic rods, reduces the output force required to tighten the drive cable to control the continued bending or return of the snake-bone pair.

[0040] Please see Figure 1 , Figure 1 This is a schematic diagram of the overall structure of the surgical robot 1 shown in some embodiments of this application. For example... Figure 1As shown, the surgical robot 1 may include at least one surgical arm 2. The surgical arm 2 is used to perform actions required for surgical procedures via tool heads 21. Tool heads 21 refer to the direct execution instruments on the surgical robot 1 that participate in surgical procedures. Different tool heads 21 may have different functions, and may include needle forceps, electric hooks, electric shovels, bipolar window forceps, bipolar Maryland forceps, cardill forceps, intestinal forceps, tweezers, graspers, needles, scalpels, scissors, cauterizers, endoscopes, and anastomosing devices, etc. The tool head 21 can be mounted on the distal end of the surgical arm 2 via a docking port, drive cable 33, or other structures. The distal end of the surgical arm 2 refers to the end of the surgical arm 2 used to insert into the human body and perform surgical procedures.

[0041] Please see Figure 2 , Figure 2 This is a schematic diagram of the overall structure of the surgical arm 2 shown in some embodiments of this application. For example... Figure 2 As shown, the surgical arm 2 may include an instrument box 22, a flexible joint component 3, an instrument tube 23, and a tool head 21. The flexible joint component 3 may include at least one flexible joint assembly 30. One end of the flexible joint component 3 can be connected to the instrument box 22 via the instrument tube 23, and the other end of the flexible joint component 3 can be connected to the tool head 21.

[0042] In this embodiment, the flexible joint component 3 or flexible joint assembly 30 refers to a structure composed of at least one snake bone pair 4, which can be tightened or loosened by the drive cable 33 to achieve directional deflection function; the instrument box 22 refers to a device that can drive the tool head 21, flexible joint assembly 30 or instrument straight tube 23 to move through the transmission structure and power source (such as servo motor and other components).

[0043] In some embodiments, the instrument tube 23 can be a hollow tubular structure; the drive cable 33 for driving the flexible joint component 3 to deflect can extend and pass through the flexible joint component 3, and extend into the instrument box 22 through the inside of the instrument tube 23, and be wound and connected to the transmission structure in a specified winding direction. Thus, the instrument box 22 can drive the transmission structure to rotate by starting the power source, thereby retracting or releasing the drive cable 33 by a certain distance, so that the flexible joint component 3 deflects in a specified direction at a specified deflection angle.

[0044] In some embodiments, the instrument tube 23 can also be rotatably mounted on the instrument case 22 to enable the self-rotation of the flexible joint component 3, thereby adjusting the movement orientation of the tool head 21 or the deflection orientation of the flexible joint component 3. In some embodiments, the tool head 21 can also be connected to the transmission structure and power source within the instrument case 22 via a dedicated tool drive cable or other transmission mechanism. Thus, the instrument case 22 can achieve the movement of the tool head 21 (e.g., the gripping of tweezers, the insertion and withdrawal of needles, etc.) or the self-rotation of the instrument tube 23 by activating the power source.

[0045] The instrument tube 23 supports the flexible joint component 3 and the tool head 21 and assists in bending. In some embodiments, the instrument tube 23 may be made of materials such as steel pipe and have a slit cut in the middle section. The length of the instrument tube 23 is determined by the trocar travel of the surgical robot 1, which refers to the distance or range that the surgical instrument (surgical arm 2 or tool head 21) enters the patient's body through the trocar during the operation.

[0046] Please see Figures 3 to 5 , Figure 3 This is a schematic diagram of the overall structure of the flexible joint component 3 shown in some embodiments of this application; Figure 4 This is a schematic diagram of the overall structure of the second flexible joint assembly 32 shown in some embodiments of this application; Figure 5 This is a schematic diagram showing the layout of the constraint cable 34 of the second flexible joint assembly 32 according to some embodiments of this application. Figures 2 to 5 As shown, the flexible joint component 3 may include two flexible joint assemblies 30, namely a first flexible joint assembly 31 and a second flexible joint assembly 32.

[0047] Each flexible joint assembly 30 may include at least one snake bone pair 4 and at least two drive cables 33. Each drive cable 33 extends and passes through each snake bone pair 4, and the connection position (or passing position) of the drive cable 33 on each bone segment 5 is symmetrical based on the rotation axis 50 corresponding to the current snake bone pair 4. One end of each drive cable 33 is fixed to the most distal bone segment 5 in the corresponding flexible joint assembly 30, which refers to the bone segment 5 in the same flexible joint assembly 30 that is closest to the tool head 21. Thus, the surgical instrument box 22 can achieve the bending or repositioning of the snake bone pair 4 to one side and the deflection of the flexible joint assembly 30 to one side by retracting and extending the drive cables 33 on both sides of the snake bone pair 4, thereby achieving the specified posture of the tool head 21.

[0048] In some embodiments, the first flexible joint assembly 31 may further include a connecting straight tube 35. Each end of the connecting straight tube 35 may have at least one snake-bone pair 4 (taking the first flexible joint assembly 31 as an example). The connecting straight tube 35 can be used to expand the working space of the flexible joint component 3 or the first flexible joint assembly 31. For example, the connection straight tube 35 can enable the first flexible joint assembly 31 to achieve a working space of 120mm during deflection. Furthermore, the connecting straight tube 35 can be a perforated steel tube to reduce the overall weight of the flexible joint component 3.

[0049] In some embodiments, each flexible joint assembly 30 can achieve reciprocating deflection in at least two degrees of freedom via multiple pairs of serpentine bones 4. Further, each flexible joint assembly 30 can include at least two pairs of serpentine bones 4 with bendable directions perpendicular to each other (i.e., two axes of rotation 50 perpendicular to each other). Figure 3 As shown, in the first flexible joint assembly 31, each end of the connecting straight tube 35 can be provided with two pairs of serpentine bones 4 whose rotational extension direction A (flexible direction) is perpendicular to each other, and the maximum bendable angle of each serpentine bone pair 4 facing either side can be set to 60 degrees. Furthermore, the serpentine bone pairs 4 arranged at both ends of the connecting straight tube 35 have the same bendable direction; in the second flexible joint assembly 32, multiple serpentine bone pairs 4 can initially be stacked sequentially in the same straight direction, and the maximum bendable angle of each serpentine bone pair 4 facing either side can be set to 45 degrees.

[0050] In some embodiments, where any flexible joint assembly 30 includes at least two pairs of serpentine bones 4 with the same axis of rotation A, the flexible joint assembly 30 may further include at least two constraint cables 34. The constraint cables 34 are used to limit the uncertain deformation of the flexible joint assembly 30, so that after directional deflection based on a specified deflection angle, it has a uniquely determined posture, thereby alleviating the problem of uncertain deformation (e.g., S-shaped deformation) of the flexible joint assembly 30 due to external loads.

[0051] Specifically, in the flexible joint assembly 30, each constraint cable 34 extends and passes through multiple pairs of serpentine bones 4. The connection positions 340 (passing positions) of the constraint cables 34 on each spur 5 (or serpentine bone pair 4) are generally symmetrical about the axis of rotation 50. Further, between two serpentine bone pairs 4 that are adjacent in the same direction of rotation A, the connection position 340 of each constraint cable 34 with the nearest spur 5 (serpentine bone pair 4) is the first connection position 341, and the connection position 340 of each constraint cable 34 with the farthest spur 5 (serpentine bone pair 4) is the second connection position 342. The first connection position 341 can be shifted by 180 degrees relative to the second connection position 342 based on the central axis of the flexible joint assembly 30. The 180-degree shift based on the central axis of the flexible joint assembly 30 can be understood as the first connection position 341 and the second connection position 342 being located on opposite sides of the central axis of the flexible joint assembly 30 when the flexible joint assembly 30 is in a straight state without deflection.

[0052] like Figure 4 , Figure 5 As shown, taking the second flexible joint assembly 32 as an example, the second flexible joint assembly 32 may include a first snake bone pair 401, a second snake bone pair 402, a third snake bone pair 403, and a fourth snake bone pair 404 arranged sequentially along the same straight direction M. The rotation axis extension directions A of the first snake bone pair 401 and the second snake bone pair 402 are perpendicular to each other, the rotation axis extension directions A of the third snake bone pair 403 and the fourth snake bone pair 404 are perpendicular to each other, and the rotation axis extension directions A of the first snake bone pair 401 and the fourth snake bone pair 404 are the same (or parallel to each other).

[0053] Furthermore, the second flexible joint assembly 32 may include four drive cables 33 and four constraint cables 34. All four drive cables 33 and four constraint cables 34 extend and pass through each snake bone pair 4, and the connection or passing positions of the four drive cables 33 and four constraint cables 34 on each segment 5 can be symmetrical about the axis of rotation 50. Furthermore, one drive cable 33 may be adjacent to one constraint cable 34. The connection position 340 between each constraint cable 34 and the segment 5 in the first snake bone pair 401 is the first connection position 341, and the connection position 340 between each constraint cable 34 and the segment 5 in the fourth snake bone pair 404 is the second connection position 342. The first connection position 341 is shifted by 180 degrees from the second connection position 342 based on the central axis M of the second flexible joint assembly 32.

[0054] In some embodiments, the first vertical distance between the first connecting position 341 and the central axis M may be equal to the second vertical distance between the second connecting position 342 and the central axis M, so that the two adjacent snake bone pairs 4 with the same bendable direction have equal bending angles when the flexible joint assembly 30 deflects; in other embodiments, the first vertical distance between the first connecting position 341 and the central axis M may be greater than or less than the second vertical distance between the second connecting position 342 and the central axis M, so that the two adjacent snake bone pairs 4 with the same bendable direction have unequal bending angles when the flexible joint assembly 30 deflects.

[0055] In this embodiment, for two adjacent snake-bone pairs 4 in the same flexible joint assembly 30 with the same bending direction A, four constraint cables 34, arranged with a 180-degree shift based on the central axis M, are connected to ensure that each snake-bone pair 4 has a fixed bending angle when deflected to one side at a specified angle. This is because the lengths of the four constraint cables 34 are fixed, and the constraint positions (i.e., connection positions 340 or insertion positions) of each constraint cable 34 with each snake-bone pair 4 are fixed. When a constraint cable 34 is pulled to one side by a bending snake-bone pair 4, since the lengths of each constraint cable 34 and the connection positions 340 remain unchanged, the other snake-bone pair 4 will also be pulled by the constraint cable 34, resulting in bending and displacement. The two snake-bone pairs 4 are connected to the specified position by a 180-degree shift of at least two constraint cables 34, thus determining a unique bending angle.

[0056] Please participate Figures 6 to 8 , Figure 6 This is a schematic diagram of the overall structure of the snake bone pair 4 as shown in some embodiments of this application; Figure 7 This is a schematic diagram of the explosion of the snake bone pair 4 as shown in some embodiments of this application; Figure 8 This is a schematic diagram of the explosion of the snake bone pair 4, as shown in other embodiments of this application. Figures 6 to 8 As shown, this application embodiment provides a snake bone pair 4, which includes two bone segments 5, a support structure 41, and at least two elastic rods 52.

[0057] In this embodiment, segment 5 refers to a snake-bone unit used to form a snake-bone pair 4 and to support the snake-bone pair 4 through mutual cooperation to achieve bending movement; support structure 41 refers to a structure disposed between two segments 5, which provides support and can limit the centers (or pivots 50) of the two segments 5 from moving closer or further apart. In this embodiment, support structure 41 can be an independent component or integrally formed with segment 5. Elastic rod 52 refers to a structure that, during the relative rotation of two segments 5, or when two segments 5 are kept stationary at a fixed angle, can bend to cooperate with the rotation of segments 5, and can also apply bidirectional constraint force to two segments 5 based on its own elastic deformation characteristics, so as to reduce or even avoid further uncertain misalignment and slippage between segments 5.

[0058] Specifically, each segment 5 can rotate based on its own axis 50. The two axes 50 in the same snake bone pair 4 are parallel to each other and have a constant distance between them. The distance between the two axes 50 is the center distance H of the snake bone pair 4. A support structure 41 is disposed between the two segments 5 to maintain a constant center distance between them. In the above technical solution, the snake bone pair 4 can maintain a constant center distance between the two segments 5 through the support structure 41 or the cooperation of the support structure 41 with the drive cable 33, thereby effectively improving the bending accuracy and bending stability of the snake bone pair 4. In addition, the support structure 41 can bear a portion of the pressure load generated when the segments 5 are tightened by the drive cable 33, thereby reducing wear between the segments 5, extending the service life of the segments 5, and improving the bending accuracy of the snake bone pair 4. The axis 50 can refer to an actual structure in the snake bone pair 4, or it can refer to a specific axial position on each segment 5; in this embodiment, the axis 50 is the reference axis around which each segment 5 rotates, usually referring to a straight line position on the segment 5.

[0059] Furthermore, each segment 5 includes two constraint arc surfaces 53 of equal size (or radius), coinciding central axes, and facing opposite directions, namely a first constraint arc surface 531 and a second constraint arc surface 532. The elastic rod 52 includes a first elastic rod 521 and a second elastic rod 522, both connected between the two segments 5, and their projections onto the normal plane of the rotation axis 50 are cross-symmetrical (please refer to...). Figures 9 to 11 (As shown); the first elastic rod 521 is in contact with the first constraint arc surface 531, and the second elastic rod 522 is in contact with the second constraint arc surface 532. Furthermore, the orthographic projections of the first constraint arc surface 531 and the second constraint arc surface 532 on the normal plane of the rotation axis 50 on the same joint 5 are symmetrical about the first plane 500, and the central axis of the first plane 500 coincides with the central axis of the constraint arc surface 53 and the rotation axis 50.

[0060] Please combine Figures 9 to 11As shown, in the same snake bone pair 4, with the two rotation axes 50 parallel and the distance between them constant, at least one pair of elastic rods 52 are connected between the two segments 5, and the projections of the pair of elastic rods 52 along the extension direction A of the rotation axis are cross-symmetrical. The first elastic rod 521 and the second elastic rod 522 are both in contact with the constraint arc surface 53, which is the premise for the two segments 5 to achieve symmetrical rotation based on the constraint of the cross elastic rods 52. The segment 5 includes a segment base 51. The end faces of the two segment bases 51 in the same snake bone pair 4 that are opposite to each other and adjacent to each other are the first end faces 510. The constraint arc surface 53 is provided on the first end faces 510 of the two segment bases 51 and protrudes outward relative to the first end faces 510. In the embodiment of this application, the first plane 500 is perpendicular to the first end face 510, and the first plane 500 coincides with the rotation axis 50 of the segment 5. Therefore, the axes of the first constraint arc surface 531 and the second constraint arc surface 532 set on the same bone segment 5 coincide, and the plane where the coincident axis and the rotation axis 50 of the bone segment 5 are located is the first plane 500.

[0061] The two constraint arc surfaces 53 have the same shape and size, ensuring that the deformation of the same pair of elastic rods 52 under the compression of the constraint arc surfaces 53 during the bending of the snake bone pair 4 is consistent. Furthermore, under the bidirectional constraint force of the pair of elastic rods 52 with consistent deformation, the two skeletal joints 5 can achieve relative rotation with the same rotation angle, thereby realizing the symmetrical motion configuration of the snake bone pair 4. Under the symmetrical motion configuration, the two skeletal joints 5 rotate towards each other with equal rotation angles, reducing the probability of uncertain deformation (which can be called S-shaped deformation or parallelogram deformation) of the snake bone pair 4 due to external forces.

[0062] Furthermore, the first elastic rod 521 and the second elastic rod 522 have the same shape, size, and length, and also have the same inclination angle relative to the first end face 510. The constraint arc surface 53 that is in contact with the elastic rod 52 can be semi-circular or partially circular. The elastic rod 52 can be made of a spring with elasticity, and is made of metal or non-metal materials with good elastic deformation and tensile strength. The cross-sectional shape of the elastic rod 52 can be circular or rectangular. Furthermore, the two ends of the elastic rod 52 can be set as boss-shaped structures for easy embedding or fixing. The two ends of the elastic rod 52 can be fixed to the connecting grooves at the ends of the constraint arc surface 53 on the two joints 5 by embedding methods such as welding, threaded connection, and crimping.

[0063] In the above technical solution, the two joints 5 are rotatably connected by the support structure 41, which can maintain a constant distance between the two rotating shafts 50. When the rotating shafts 50 are parallel to each other and the distance is constant, the first elastic rod 521 and the second elastic rod 522 are arranged in a cross-symmetrical state, and the two elastic rods 52 are both attached to the constraint arc surface 53 on each joint 5. This allows the two elastic rods 52 to apply equal constraint forces to the constraint arc surface 53 and each joint 5 during the bending process of the snake bone pair 4 and when the snake bone pair 4 is in a stationary state. This enables the snake bone pair 4 to achieve a symmetrical motion configuration and has a unique shape at a specified bending angle. This reduces the probability of uncertain misalignment and slippage between the joints 5 and improves the bending accuracy and load deformation resistance of the snake bone pair 4. The two constraint arc surfaces 53 are symmetrically arranged based on the first plane 500, which can make the force on the joints 5 more uniform and balanced, and improve the stability and consistency of the rotation of the joints 5 and the overall stability of the snake bone pair 4.

[0064] Based on this, the elastic deformation capability of the elastic rod 52 can reduce the output force required for the drive cable 33 to tighten and drive the snake pair 4 to bend. The elastic rod 52 can also provide an auxiliary force based on its deformation recovery characteristics during the return process of the snake pair 4, similarly reducing the output force required for the drive cable 33 to drive the snake pair 4 to return. In addition, the support structure 41 can share the pressure load generated by the interaction of the joints 5 when the drive cable 33 tightens, thereby reducing the wear of the joints 5 and extending the service life of the joints 5 and the snake pair 4.

[0065] In some embodiments, the distance between the two rotating shafts 50 is the center distance of the snake bone pair 4, and the radii R1 of the first constraint arc surface 531 and the radii R2 of the second constraint arc surface 532 are both no more than half of the center distance H. In the above technical solution, the radius of the constraint arc surface 53 is no more than half of the center distance, which helps to reduce the processing difficulty of the bone joint 5 and the assembly difficulty of the snake bone pair 4, and improves the smoothness, flexibility and stability of the bending of the snake bone pair 4. Further, the range of values ​​for the radius R of the constraint arc surface 53 on each bone joint 5 is as follows: When the radius R1 of the first constraint arc surface 531 and the radius R2 of the second constraint arc surface 532 are both equal to half the center distance H, the first elastic rod 521 and the second elastic rod 522 can be accommodated in the grooves on their respective constraint arc surfaces 53 to reduce wear.

[0066] In some embodiments, on the same joint 5, a first constraint arc surface 531 and a second constraint arc surface 532 are connected or partially overlapped to form a double constraint arc surface. Specifically, in the same snake bone pair 4, the double constraint arc surfaces on the two joints 5 remain symmetrical during the bending process of the snake bone pair 4, and the symmetry reference plane is also one of the normal planes of the line connecting the center points of the two rotating shafts 50. In the above technical solution, the first constraint arc surface 531 and the second constraint arc surface 532 are connected or partially overlapped to form a semi-circular double constraint arc surface, making the structure of the joint 5 simpler and more compact, and more conducive to the processing and assembly of the snake bone pair 4. In other embodiments, the same pair of elastic rods 52 can also be attached to the independent first constraint arc surface 531 and second constraint arc surface 532 respectively. This solution can also reduce the probability of uncertain misalignment and sliding between joints 5 and improve the bending accuracy and load deformation resistance of the snake bone pair 4.

[0067] In some embodiments, the snake bone pair 4 includes at least one pair of adjacent first elastic rods 521 and second elastic rods 522. The edges of the first elastic rods 521 and second elastic rods 522 adjacent to each other are provided with relief grooves 520. The first elastic rods 521 and second elastic rods 522 are arranged crosswise through the relief grooves 520 and are independent of each other.

[0068] In the above technical solution, the adjacent first elastic rod 521 and second elastic rod 522 can be arranged side by side through the design of the clearance groove 520, reducing motion interference. Each elastic rod 52 can be bent and twisted independently, thereby improving the flexibility, smoothness, reliability and stability of the snake bone bending. In addition, the setting of the clearance groove 520 makes the installation and disassembly process of the first elastic rod 521 and the second elastic rod 522 simpler, and can save space between the bases 51 of the two joints, making the layout of the support structure 41, multiple elastic rods 52, drive cable 33 and constraint cable 34 more reasonable and compact.

[0069] In some embodiments, the surfaces of the two segments 5 of the snake bone pair 4 that are opposite to each other and adjacent to each other are first end faces 510. On either first end face 510, along a direction perpendicular to the rotation axis 50, both ends of the first end face 510 are provided with limiting inclined surfaces 512 that are inclined relative to the first end face 510 and have equal inclination angles. In this embodiment, the limiting inclined surfaces 512 on the bases 51 of the two segments can be designed according to the maximum bendable angle of the snake bone pair 4. When the two segments 5 rotate to the maximum rotatable angle, the limiting inclined surfaces 512 of the two segments 5 abut against each other to play a limiting role. In this embodiment, the two segments 5 of the snake bone pair 4 can rotate up to ±90°; the inclination angle of the limiting inclined surfaces 512 relative to the first end face 510 can reach up to ±90 degrees. In the above technical solution, the setting of the limiting inclined surface 512 can limit the maximum rotation angle of the joint 5 to one side, that is, limit the maximum bending angle of the snake bone pair 4 to one side, reduce the edge collision and wear between the joints 5, and extend the service life of the joints 5.

[0070] In some embodiments, each joint 5 includes multiple sets of rope holes 511, which are symmetrically arranged on both sides of the rotating shaft 50. Each rope hole 511 is located on the first end face 510 and extends in a direction perpendicular to the first end face 510. The rope holes 511 are used to accommodate the drive cable 33 or the constraint cable 34. Furthermore, the multiple rope holes 511 for threading or connecting the drive cable 33 can be symmetrically arranged on both sides of the rotating shaft 50. For example, each side of the rotating shaft 50 has two rope holes 511 for connecting the drive cable 33. The snake joint 4 can achieve a bending action towards one side by tightening and loosening the two drive cables 33.

[0071] In the above technical solution, the arrangement of multiple sets of rope holes 511 makes the overall structure of the snake bone pair 4 and the flexible joint assembly 30 more compact, and also reduces the pulling and interference on the restraint cable 34 or drive cable 33 when the joint 5 rotates. Furthermore, the symmetrical arrangement of the rope holes 511 based on the pivot 50 ensures that the connection positions of the drive cables 33 on both sides of the snake bone pair 4 and each joint 5 are symmetrical and equidistant based on the pivot 50. When the snake bone pair 4 can achieve a symmetrical motion configuration, the symmetrical arrangement of the rope holes 511 allows the drive cables 33 on both sides of the snake bone pair 4 to achieve consistent extension and retraction with balanced lever arms, thereby extending the service life of the drive cables 33.

[0072] When the snake-bone pair 4 is bent, the shortening length of one side of the drive cable 33 is equal to the elongation length of the other side, meaning the drive cables 33 on both sides of the snake-bone pair 4 extend and retract in unison. Furthermore, the perpendicular distance between the drive cables 33 on both sides of the pivot 50 and the intersection point O of the projection of the elastic rod 52 can be considered as the lever arm corresponding to the tightening of the drive cable 33 when the snake-bone pair 4 is in any posture, and when one side of the drive cable 33 drives the snake-bone pair 4 to continue bending or return to its original position (or when the drive cable 33 drives the snake-bone pair 4 to bend to any side). For example, the lever arm corresponding to the tightening of the right drive cable 33 to drive the snake-bone pair 4 to continue bending to the right is equal to the lever arm corresponding to the tightening of the left drive cable 33 to drive the snake-bone pair 4 to return to its straight position to the left. This state of equal lever arm magnitude can be considered as lever arm balance. That is, regardless of the posture of the snake-bone pair 4 or which side it is about to bend to, the force required to tighten the drive cables 33 on both sides of the snake-bone pair 4 is equal. As a result, the probability of deformation of the drive cables 33 on both sides of the snake bone is reduced, the service life of the drive cables 33 is extended, and the consistency of the service life of each drive cable 33 is improved.

[0073] In some embodiments, the double snake bone pair can be formed by connecting and interleaving two snake bone pairs 4 that are perpendicular to each other in the direction A of the rotating shaft. Furthermore, each snake bone pair 4 can be bent up to 90° in any direction. Four drive cables 33 are symmetrically arranged on both sides of the rotating shaft 50 of each snake bone pair 4, and the four drive cables 33 can be evenly distributed circumferentially on the first end face 510 of each bone segment 5. The retraction of every two adjacent drive cables 33 corresponds to the bending of the snake bone pair 4 to one side, thereby realizing the bending of the snake bone pair 4 in four directions around two straight lines, with each straight line corresponding to bending in both directions.

[0074] In some embodiments, in the snake-bone pair 4, the end faces of the two segments 5 that are opposite to each other and adjacent to each other are the first end faces 510; on the first end faces 510, each end of the rotating shaft 50 is provided with a first elastic rod 521 and a second elastic rod 522. In the above technical solution, the provision of a first elastic rod 521 and a second elastic rod 522 at each end of the rotating shaft 50 makes the snake-bone pair 4 have good symmetry, which is conducive to the uniform distribution of load, reduces local stress concentration, and improves the stability and load-bearing capacity of the overall structure of the snake-bone pair 4.

[0075] In other embodiments, in the snake-bone pair 4, the surfaces of the two segments 5 facing each other and adjacent to each other are first end faces 510. All first elastic rods 521 are provided at one end of the rotating shaft 50, and all second elastic rods 522 are provided at the other end of the rotating shaft 50. In the above technical solution, elastic rods 52 are provided at each end of the rotating shaft 50, which is beneficial to the uniform distribution of load, reduces local stress concentration, and improves the stability and load-bearing capacity of the overall structure of the snake-bone pair 4.

[0076] In other embodiments, in the snake bone pair 4, the end faces of the two bone segments 5 that are opposite to each other and adjacent to each other are the first end faces 510. Only one end of the rotating shaft 50 is provided with a first elastic rod 521 and a second elastic rod 522, and the other end of the rotating shaft 50 is provided with only the first elastic rod 521 or the second elastic rod 522; or, the other end of the rotating shaft 50 is not provided with an elastic rod 52; or, the other end of the rotating shaft 50 is provided with a third elastic rod and / or a fourth elastic rod. The radius of the constraint arc surface 53 corresponding to the first elastic rod 521 and the second elastic rod 522 can be greater than or less than the radius of the constraint arc surface corresponding to the third elastic rod and the fourth elastic rod. The orthographic projections of the third elastic rod and the fourth elastic rod on the normal plane of the rotating shaft can also be in a cross-symmetrical state.

[0077] like Figure 7 As shown, in some embodiments, the support structure 41 may include at least one connecting pin assembly 43. Each connecting pin assembly 43 may include at least one connecting pin 431, and each connecting pin 431 may include two connecting pin shafts 4311 and a connecting rod 4312. The connecting rod 4312 is vertically connected between the two parallel connecting pin shafts 4311 and may be integrally formed with the connecting pin shafts 4311. In the same snake bone pair 4, one connecting pin shaft 4311 is rotatably connected to one bone segment 5, and the axis of one connecting pin shaft 4311 is fixedly aligned with the rotation axis 50 of one bone segment 5. In the above technical solution, the snake bone pair 4 fixes the center distance between the two bone segments 5 through the connecting pins 431, making it difficult for the two bone segments 5 to approach or move away from each other during the rotation process, thereby improving the bending accuracy and bending reliability of the snake bone pair 4.

[0078] Furthermore, each connecting pin assembly 43 may include two connecting pins 431 and an anti-detachment component 432. The anti-detachment component 432 is disposed between the two connecting pins 431 and achieves connection, synchronous rotation and anti-detachment in the direction A of the shaft extension by engaging the limiting groove with the limiting insert plate.

[0079] like Figure 8As shown, in some embodiments, each support structure 41 may include multiple arc-shaped top units 42. In the same snake bone pair 4, the arc-shaped top units 42 may be respectively disposed on the first end faces 510 of two bone segments 5 that are opposite to each other and adjacent, and may be integrally formed with the bone segments 5. Specifically, each arc-shaped top unit 42 has an arc-shaped top surface 420, and the two arc-shaped top surfaces 420 are in rolling contact and have equal radii. One arc-shaped top surface 420 is disposed on the first end face 510 of one bone segment 5 and convex outward relative to the first end face 510, and the other arc-shaped top surface 420 is disposed on the first end face 510 of another bone segment 5 and convex outward relative to the first end face 510. The axis of the arc-shaped top surface 420 coincides with the rotation axis 50, and the radius of the arc-shaped top surface 420 is equal to half the center distance of the snake bone pair 4. In the above technical solution, the setting of the arc on the top surface 420 can reduce the wear of the joint 5. The arc on the top surface 420 makes rolling contact with each other, which can improve the smoothness of the bending of the snake bone 4 and the stability of the structure, improve the load-bearing capacity of the joint 5, and reduce the processing difficulty of the joint 5.

[0080] In some embodiments, in a pair of arc-shaped top surfaces that are in rolling contact with each other, at least one side of one arc-shaped top surface 420 is provided with a stop 421. The limiting movement direction corresponding to the stop 421 is the same as the extension direction A of the rotating shaft, and the radius corresponding to the stop 421 is greater than half of the center distance H. In the above technical solution, the stop 421 provided on at least one side of the arc-shaped top surface 420 can reduce the probability of misalignment between the joints 5 along the rotating shaft 50 during the bending process of the snake bone pair 4, thereby improving the bending accuracy of the snake bone pair 4.

[0081] In the above technical solution, the snake bone pair 4 can fix the center distance H between the two bone segments 5 through various types of support structures 41, so that the rotating shafts 50 of the two bone segments 5 are difficult to approach or move away from each other during the rotation process (the cooperation of the arc-shaped top unit 42 and the drive cable 33 to tighten and connect several bone segments 5 can make it difficult for the bone segments 5 to move away from or approach each other, and the connecting pin assembly 43 can also play the same role). The constant center distance ensures that the centers of the bone segments 5 will not suddenly approach or move away from each other under the tension of the drive cable 33, thereby reducing the probability of the snake bone pair 4 being "accidentally impacted" or "dislocated".

[0082] Please see Figures 9 to 10 , Figure 9 This is a front view schematic diagram of the snake bone pair 4 in a flat state, as shown in some embodiments of this application; Figure 10 This is a front view schematic diagram illustrating the snake bone pair 4 in a 90-degree bent state, as shown in some embodiments of this application. Figures 9 to 10As shown, in some embodiments, when the snake bone pair 4 is in a straight state, the two segments 5 are opposite each other and their adjacent end faces are parallel, that is, the snake bone pair 4 as a whole remains straight and without bending. The first elastic rod 521 is tangent to the first constraint arc surface 531 on the two segments 5, and the second elastic rod 522 is tangent to the second constraint arc surface 532 on the two segments 5. Specifically, the two elastic rods 52, which are originally in a straight state, can be inserted between the two segments 5 in a non-deformed state and are in contact with the constraint arc surface 53 on the base 51 of each segment. When the two segments 5 rotate relative to each other, the two cross-arranged elastic rods 52 are deformed by the compressive force of the constraint arc surface 53. Since the constraint arc surface 53 on the two segments 5 has the same shape and size, the two elastic rods 52 always maintain a cross-symmetrical state and the deformation is consistent. Figure 10 As shown, when the snake bone pair 4 bends to one side to 90 degrees, the projections of the two elastic rods 52 on the extension direction A of the rotation axis still maintain a cross-symmetrical state, that is, the snake bone pair 4 can still maintain a symmetrical configuration.

[0083] In the above technical solution, the design of the elastic rod 52 being tangent to the constraint arc surface 53 reduces the friction between the two, thereby reducing the wear of the joint 5 and extending the service life of the snake bone pair 4; the design of the elastic rod 52 being tangent to the constraint arc surface 53 makes the manufacturing process of the joint 5 and the assembly process of the snake bone pair 4 simpler and the manufacturing cost lower.

[0084] Please see Figure 11 , Figure 11 This is a schematic diagram illustrating the geometric principle of a serpentine four-symmetric motion configuration shown in some embodiments of this application. For example... Figure 11 As shown, in some other embodiments, when the snake bone pair 4 is in a straight state, the two segments 5 are opposite each other and their adjacent end faces are parallel to each other, that is, the snake bone pair 4 as a whole remains straight and without bending. A first elastic rod 521 wraps around the first constraint arc surface 531 of each segment 5, and a second elastic rod 522 wraps around the second constraint arc surface 532 of each segment 5.

[0085] Specifically, the two elastic rods 52, initially in a straight state, can be inserted between the two joints 5 in a bent deformed state, closely adhering to the constraint arc surface 53 on the base 51 of each joint; or, the two elastic rods 52, initially in an S-shaped bent state, can be inserted between the two joints 5 in a non-deformed state, closely adhering to the constraint arc surface 53 on the base 51 of each joint. When the two joints 5 rotate relative to each other, the two intersecting elastic rods 52 are further deformed or recover their deformation under the pressure of the constraint arc surface 53. Since the constraint arc surface 53 on the two joints 5 has the same shape and size, the two elastic rods 52 always maintain a cross-symmetrical state and the deformation is consistent. In the above technical solution, the design of the elastic rods 52 wrapping around the constraint arc surface 53 increases the contact area between the elastic rods 52 and the constraint arc surface 53, making the force transmission more uniform and stable, thereby improving the bending stability and shape maintenance stability of the snake bone pair 4, and improving the load-bearing capacity and structural strength of the snake bone pair 4.

[0086] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A snake bone pair, comprising two segments, each segment capable of rotating about its respective axis, characterized in that, The snake bone pair also includes: A support structure is provided between two vertebrae parallel to the axis of rotation, so that the distance between the two axes of rotation of the same snake bone pair is constant; A first elastic rod and a second elastic rod are both connected between two vertebrae, and their orthographic projections on the normal plane of the rotation axis are symmetrically arranged. Each vertebra includes a first constraint arc surface and a second constraint arc surface with equal radii and coincident central axes. The first elastic rod is in contact with the first constraint arc surface, and the second elastic rod is in contact with the second constraint arc surface. The orthographic projections of the first constraint arc surface and the second constraint arc surface on the normal plane of the rotation axis on the same vertebra are symmetrical based on a first plane, which coincides with the central axis and the rotation axis.

2. The snake bone pair according to claim 1, characterized in that, When the snake bone pair is in a straight state, the two bone segments are opposite each other and their adjacent end faces are parallel to each other. The first elastic rod is tangent to the first constraint arc surface on the two bone segments, and the second elastic rod is tangent to the second constraint arc surface on the two bone segments.

3. The snake bone pair according to claim 1, characterized in that, When the snake bone pair is in a straight state, the two bone segments are opposite each other and their adjacent end faces are parallel to each other. The first elastic rod wraps around the first constraint arc surface of each bone segment, and the second elastic rod wraps around the second constraint arc surface of each bone segment.

4. The snake bone pair according to claim 1, characterized in that, The distance between the two rotating shafts is the center distance of the snake bone pair, and the radius of the first constraint arc surface and the radius of the second constraint arc surface do not exceed half of the center distance.

5. The snake bone pair according to claim 1, characterized in that, On the same joint, a first constraint arc surface connects with or partially overlaps with a second constraint arc surface to form a double constraint arc surface.

6. The snake bone pair according to claim 1, characterized in that, The snake-bone pair includes at least one pair of first elastic rods and second elastic rods arranged adjacent to each other. The first elastic rods and the second elastic rods are provided with relief grooves on their adjacent edges. The first elastic rods and the second elastic rods are arranged crosswise through the relief grooves and are independent of each other.

7. The snake bone pair according to any one of claims 1-6, characterized in that, In the snake bone pair, the two bone segments facing each other and adjacent end faces are the first end faces; each end of the rotating shaft is provided with the first elastic rod and the second elastic rod.

8. The snake bone pair according to any one of claims 1-6, characterized in that, In the snake bone pair, the surfaces of the two bone segments that are opposite to each other and adjacent to each other are the first end faces; the first elastic rod is provided at one end of the rotating shaft, and the second elastic rod is provided at the other end of the rotating shaft.

9. A flexible joint assembly, characterized in that, The flexible joint assembly includes: At least two snake bone pairs as described in any one of claims 1-8; wherein the rotation axes of at least two snake bone pairs extend in the same direction; At least two drive cables and at least two constraint cables are provided, each of which extends and passes through each of the snake bone pairs, and the connection positions of the drive cables and constraint cables on each bone segment are symmetrical based on the axis of rotation; one end of each drive cable is fixedly connected to the most distal bone segment of the flexible joint assembly. Between the two snake bone pairs that extend in the same direction and are closest in position, the connection position of each constraint cable with the nearest snake bone pair is the first connection position, and the connection position of each constraint cable with the farthest snake bone pair is the second connection position. The first connection position is shifted by 180° based on the central axis of the flexible joint assembly compared to the second connection position.

10. A surgical operating arm, characterized in that, The surgical arm includes at least one flexible joint assembly as described in claim 9.

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