Articulated member and surgical instrument

Abstract

An articulated member and a surgical instrument are provided. The articulated member includes: a plurality of rotatable joints connected sequentially along a lengthwise direction of the articulated member, each including a first section and a second section rotatable relative to each other about a rotation axis perpendicular to a central axis of the articulated member, the second section of a proximal joint and the first section of a distal joint among two adjacent rotatable joints constitutes an joint body; and a plurality of coupling tendons each extending through the plurality of joint bodies, with two ends being fixed to the proximal and distal ends of the articulated member respectively, each coupling tendon extends from the first section of a first rotatable joint along a first extension axis to a first joint body, changes its orientation within at least two joint bodies by bypassing the central axis, and then leaves a last joint body along a second extension axis and is fixed to the second section of a last rotatable joint, the first and second extension axes are parallel to and symmetrical about the central axis. In this way, coupling tendons do not occupy a central channel of the articulated member, so that the central channel can be made smaller to reduce a size of the articulated member.

Description

[0001] ARTICULATED MEMBER AND SURGICAL INSTRUMENT

[0002] TECHNICAL FIELD

[0003] The present application relates to the field of medical devices, in particular to an articulated member and a surgical instrument including the articulated member.

[0004] BACKGROUND ART

[0005] Surgical instruments forming part of a robotic surgical system generally include actuation tendons, articulated members, and end effectors. The actuation tendon may extend from other components of the robotic surgical system to the interior of the articulated member to control and drive movement of the articulated member and the end effector. The articulated member may include a plurality of rotatable joints arranged adjacent to each other to provide a certain freedom of movement to the end effector and to adjust its orientation. The end effector may be used to perform specific actions required in the surgical procedures.

[0006] When the rotatable joints bend at sharp angles, the actuation tendons passing through the joints follow the sharp bends resulting in high friction and high wear and tear damage. Distributing the bending angle between multiple joints can improve the performance of instruments. For example, two joints bend in the same direction at 45 degrees each results in the overall bending of 90 degrees. Most of the existing technologies use two pairs of actuation tendon to drive the two serial joints. The two pairs of actuation tendon pass through the instrument body to the back of the instrument where the two pairs of tend movement is coupled so that the two joints can be moved in unison. The number of tendons passing through the instrument body and the coupling mechanism increase the complexity of the mechanism. A mechanism to couple the joints within the articulation member, with only one pair of actuation tendon to drive the joints moving in the same direction to simplify the mechanism is highly desirable.

[0007] In the surgical instruments, a central channel near a central axis of the articulated member is extremely important, as connection lines pass through the central channel for supplying power, fluid, drugs, etc., to the end effector. Therefore, the functionality of the end effector is largely limited by the size of the central channel. However, in the existing surgical instruments, coupling tendons for coupling multiple joints more or less occupy the central channel to ensure movement of the articulated members, thus limiting the functionality of the end effector. Thereby, it has become an urgent issue as how to effectively control and drive movement of the articulated member, while keeping the central channel thereof unobstructed. SUMMARY OF THE INVENTION

[0008] In view of the above, it is an object of the present application to efficiently control and drive movement of the articulated member with simplified joint coupling mechanism while keeping the central passage thereof unobstructed. This object can be achieved by the technical solutions as set forth in the appended claims.

[0009] In a first aspect, the present application provides an articulated member which includes a plurality of rotatable joints and a plurality of coupling tendons. The rotatable joints are connected sequentially along a lengthwise direction of the articulated member. Each rotatable joint includes a first section and a second section rotatable relative to each other about a rotation axis perpendicular to a central axis of the articulated member. The second section of a proximal joint and the first section of a distal joint among two adjacent rotatable joints constitutes a joint body, and a plurality of joint bodies are distributed in series along the lengthwise direction between a proximal end and a distal end of the articulated member. The coupling tendons each extends through the plurality of joint bodies, with two ends being fixed to the proximal and distal ends of the articulated member respectively. Each coupling tendon extends from the first section of a first rotatable joint along a first extension axis to a first joint body, changes its orientation within at least two of the plurality of joint bodies by bypassing the central axis, and then leaves a last joint body along a second extension axis and is fixed to the second section of a last rotatable joint. The first extension axis and the second extension axis are parallel to and symmetrical about the central axis.

[0010] In a second aspect, the present application provides a surgical instrument which includes the articulated member as described above, and an end effector coupled to the articulated member.

[0011] As compared with the prior art, the technical solutions set forth in this application makes the coupling tendons no longer occupy valuable space in the central channel of the articulated member, by configuring the coupling tendon to change its orientation within at least two joints by bypassing the central axis as the coupling tendon extends in the articulated member along a lengthwise direction thereof. Accordingly, the central channel can be made smaller to reduce the size of the articulated member, making the articulated member suitable for more body passages; alternatively, the central channel of the same size can provide more space for the connection lines of the end effector.

[0012] DESCRIPTION OF THE DRAWINGS

[0013] To better illustrate technical solution of the present application, a brief description of the accompanying drawings required for describing the embodiments or prior art is provided below. Obviously, the following drawings relate to only some embodiments of the present application, and other drawings may be obtained from these drawings without creative effort by a person of ordinary skill in the art.

[0014] FIG. 1 is a schematic structural view of an articulated member according to an embodiment of the present application;

[0015] FIG. 2 is a side view of the articulated member shown in FIG. 1;

[0016] FIG. 3 is another schematic structural view of the articulated member shown in FIG. 2, where the external structure is treated in transparency to illustrate an extended state of the coupling tendons;

[0017] FIG. 4 is a schematic structural view of the coupling tendons inside the articulated member shown in FIG. 3;

[0018] FIG. 5 is a schematic structural view of the first joint in the articulated member shown in FIG. 1;

[0019] FIG. 6 is a schematic cross-sectional view along line A-A in FIG. 2;

[0020] FIG. 7 is a schematic cross-sectional view along line B-B in FIG. 2;

[0021] FIG. 8 is a schematic cross-sectional view of the articulated member shown in FIG. 1, where the cross-section passes through two coupling tendons on opposite sides;

[0022] FIG. 9 is another schematic cross-sectional view of the articulated member shown in FIG. 1, with the coupling tendons omitted;

[0023] FIG. 10 is another schematic structural view of the articulated member shown in FIG. 1, where the external structure is treated in transparency to illustrate an extended state of the actuation tendons and the coupling tendons;

[0024] FIG. 11 is a schematic structural view of the actuation tendons and the coupling tendons inside the articulated member shown in FIG. 10;

[0025] FIG. 12 is a schematic structural view of the articulated member in a bent state according to an embodiment of the present application;

[0026] FIG. 13 is another schematic structural view of the articulated member shown in FIG. 12, where the external structure is treated in transparency to illustrate an extended state of the coupling tendons;

[0027] FIG. 14 is a schematic structural view of a surgical instrument according to an embodiment of the present application;

[0028] FIG. 15 is a schematic structural view of an articulated member according to another embodiment of the present application; and

[0029] FIG. 16 is a schematic structural view of the coupling tendons inside the articulated member shown in FIG. 15.

[0030] Reference numerals:

[0031] 1-articulated member; 11-first joint; 12-second joint; 13-third joint; 14-fourth joint; 15-first section; 16-second section; 17-joint protrusion; 18-joint recess; 2- coupling tendon; 21-first coupling tendon; 22-second coupling tendon; 23-third coupling tendon; 24-fourth coupling tendon; 211, 221, 231, 241-proximal portion; 212, 222, 232, 242-intermediate portion; 213, 223, 233, 243-distal portion; 215, 225, 235, 245-transition portion; 3-coupling tendon accommodation part; 31-straight section; 32-diverting section; 4-joint body; 41-first joint body; 42-second joint body; 43-third joint body; 5-rotation axis; 51-first rotation axis; 52-second rotation axis; O-central axis; Xl-first extension axis; X2-second extension axis; 6-actuation tendon; 61-first actuation tendon; 62-second actuation tendon; 63-third actuation tendon; 64-fourth actuation tendon; 7-actuation tendon accommodation part; 8-connection line; 9- central channel; 10-surgical instrument; 20-end effector; 201-fixation part; 202- manipulation part.

[0032] DETAILED DESCRPTION OF THE EMBODIMENTS

[0033] In the following description, specific details are presented for the purpose of illustration only and not for limitation, so as to provide a thorough understanding of some embodiments of the present application. However, it is evident to those skilled in the art that the present application can be implemented in other embodiments without such specific details. In some instances, detailed description of well-known systems, devices, circuits, and methods are omitted so that unnecessary details will not interfere with the description of this application.

[0034] It is to be understood that in the description of this application, the terms "center", "central", "longitudinal", "lengthwise", "circumferential", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship based on the accompanying drawings are solely for the purpose of describing this application, and are not intended to indicate or imply that the elements referred to must be of a particular orientation, constructed and operated in a particular orientation. The terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying the relative importance or number of technical features. The term "plurality" is intended to mean two or more, unless otherwise specified. Further, the terms "includes" and "has" and any variations thereof are intended to be non-exclusive. The terms "connected", "fixed", "secured", etc., shall be understood in a broad sense and may, for example, refer to a detachable connection or an integral connection, a mechanical or electrical connection, a direct connection or an indirect connection via a medium. For those skilled in the art, the specific meanings of the above terms can be understood on a case-by-case basis.

[0035] Technical solutions in the embodiments of this application will be described in detail below in conjunction with the accompanying drawings. Referring to FIGS. 1, 2 and 3, provided in a first aspect of the present application is an articulated member 1, which includes a plurality of rotatable joints connected sequentially along a lengthwise direction of the articulated member 1. Each rotatable joint includes a first section 15 and a second section 16 rotatable relative to each other about a rotation axis 5. Each rotation axis 5 is perpendicular to a central axis O of the articulated member 1. The central axis O is a straight line through the center of each cross-section of the articulated member 1 when the articulated member 1 is in its straight configuration, as shown in FIG. 2. The direction of the central axis O is parallel to the lengthwise direction of the articulated member 1. That is, each rotatable joint has a rotation axis 5 passing through its center, to enable a first section 15 of the rotatable joint to rotate relative to a second section 16 about the rotation axis 5.

[0036] Among any two adjacent rotatable joints, the second section 16 of a proximal joint and the first section 15 of a distal joint constitutes a joint body 4. Referring to FIGS. 1-3, for example, the plurality of rotatable joints includes a first joint 11, a second joint 12, a third joint 13 and a fourth joint 14 connected in sequence along the lengthwise direction of the articulated member 1. A second section 16 of the first joint 11 and a first section 15 of the second joint 12 constitutes the first joint body 41, a second section 16 of the second joint 12 and a first section 15 of the third joint 13 constitutes the second joint body 42, and a second section 16 of the third joint 13 and a first section 15 of the fourth joint 14 constitutes the third joint body 43. A plurality of joint bodies 4 are distributed in series along the lengthwise direction between the proximal and distal ends of the articulated member 1. The proximal end of the articulated member 1 is an end that is close to a driving power source when in use, and the distal end is an end that is close to the end effector when in use, i.e., an end away from the driving power source.

[0037] The articulated member 1 further includes a plurality of coupling tendons 2. Each coupling tendon 2 extends through the plurality of joint bodies 4, with two ends being fixed to the proximal and distal ends of the articulated member 1, respectively. Each coupling tendon 2 extends from a first section 15 of the first rotatable joint along a first extension axis XI to the first joint body, changes its orientation within at least two of the plurality of joint bodies by bypassing (or avoiding) the central axis O, and then leaves a last joint body along a second extension axis X2 and is fixed to a second section of the last rotatable joint. Both the first extension axis XI and the second extension axis X2 are parallel to and symmetrical about the central axis O. As shown in FIGS. 1 and 3, the coupling tendon 2 extends from the first section 15 of the first joint 11 through the second section 16 of the first joint 11 to the first section 15 of the second joint 12, and so on, until it is connected to the second section 16 of the fourth joint 14. Specifically, the coupling tendon 2 is initially led parallel to the central axis O of the articulated member on the first side of the central axis O, along the first extension axis XI. The coupling tendon 2 then passes through three joint bodies 4, changing its orientation relative to the central axis within two of the joint bodies, but not through the central axis O. Finally, the coupling tendon 2 extends from the last joint body along the second extension axis X2, parallel to the central axis O of the articulated member, and is then located on the second side of the central axis, finally secured to the second section 16 of the fourth joint 14, where the second side is diagonally opposite to the first side. By "changing orientation", it is meant that the coupling tendon switches from one axis parallel to the central axis to another axis parallel to the central axis, as it travels through the joint body, the two axes being parallel to but not coincident with each other.

[0038] The coupling tendon 2 changes its orientation relative to the central axis within at least two joint bodies as it travels inside the articulated member, thereby enabling multiple rotatable joints to be coupled, without a need for coupling tendons 2 to pass through the central channel of the articulated member. In other words, the coupling tendons 2 will no longer occupy valuable space in the central channel, so the central channel can be made smaller to reduce the size of the articulated member, making the articulated member suitable for more body channels; alternatively, the central channel of the same size can provide more space for connection lines of the end effector.

[0039] Furthermore, each joint body 4 is configured to conceal the plurality of coupling tendons 2 extending therethrough, which means that each coupling tendon 2 is concealed within a joint body 4 as it changes orientation. The portions of the coupling tendons 2 that provide the change of orientation are the portions of the coupling tendon 2 exposed to the greatest interaction forces and are, therefore, the portions most vulnerable to friction and wear. Concealing those portions within the joint bodies 4 allows the bending angles and contact surfaces to be controlled and provides protection from the external environment, thereby reducing the impacts of friction and wear. This can improve the robustness of the articulated member and reduce the likelihood of damage or failure.

[0040] In some embodiments, the proximal end of the articulated member 1 is located at the first section 15 of the first rotatable joint, and the distal end is located at the second section 16 of the last rotatable joint. As shown in FIG. 1, the first section 15 of the first joint 11 may be considered as a proximal end of the articulated member 1, and the second section 16 of the fourth joint 14 may be considered as a distal end of the articulated member 1. Each joint body 4 includes a second section 16 of the proximal joint and a first section 15 of the distal joint among two adjacent rotatable joints, and the first section 15 and the second section 16 constituting the joint body 4 may be fixed to each other or formed integrally. In this way, when the rotatable joint rotates about its rotation axis, the joint bodies 4 on both sides will each participate in motion as a whole, and there will be no relative motion between the first and second sections 15, 16 within the joint body.

[0041] In some embodiments, the first rotatable joint and the last rotatable joint are each rotatable about a respective first rotation axis 51, which intersects the central axis O of the articulated member and define a first rotation plane together with the central axis O. The first extension axis XI and the second extension axis X2 are located on two sides of the first rotation plane. As shown in FIGS. 1 and 3, both the first joint 11 and the fourth joint 14 are rotatable about the first rotation axis 51, which intersects the central axis O of the articulated member 1. In the lengthwise direction of the articulated member, two rotatable joints are provided between the first rotatable joint and the last rotatable joint. The two rotatable joints are able to rotate about their respective second rotation axis 52, which intersects the central axis O of the articulated member and define a second rotation plane together with the central axis O. The first extension axis XI and the second extension axis X2 are located on two sides of the second rotation plane. The second rotation axis 52 is perpendicular to the first rotation axis 51, and the second rotation plane is perpendicular to the first rotation plane, such that the two intermediate rotatable joints are rotatable orthogonally with respect to the first and last rotatable joints, respectively. As shown in FIGS. 1 and 3, both the second joint 12 and the third joint 13 are rotatable about the second rotation axis 52, wherein the second rotation axis 52 intersects the central axis O of the articulated member 1 and is also perpendicular to the first rotation axis 51.

[0042] In some embodiments, each change of orientation of each coupling tendon 2 occurs between two rotatable joints having rotation axes defining a rotation plane together with the central axis O, the change of orientation occurring along a tendon plane that is perpendicular to the rotation plane. For example, the first coupling tendon 21 changes orientation within the second joint body 42, which is between the second and third joints 12, 13 having rotation axes 52 (FIG. 1). As mentioned above, the rotation axes 52 may be considered as defining a rotation plane with the central axis O. As such, the change of orientation of the first coupling tendon 21 occurs along a plane that is perpendicular to the rotation plane. This ensures that movement of the articulated member 1 relative to the parallel rotation axes 52 will not cause unintentional movement of the articulated member 1 relative to the other rotation axes 51. In other words, moving joints 12 and 13 will not affect joints 11 and 14.

[0043] In some embodiments, as shown in FIG. 5 illustrating the first joint 11, the first section 15 of the rotatable joint is detachably connected to the second section 16, with two opposing portions of these two sections 15, 16 tapering toward the first rotation axis 51, so as to guarantee a space for the first section 15 to rotate relative to the second section 16. The first section 15 is provided with a joint recess 18 on an end face facing the second section 16, and the second section 16 is provided with a joint protrusion 17 on an end face facing the first section 15. In an assembled state, the joint protrusion 17 is embedded into the joint recess 18. The joint recess 18 and the joint protrusion 17 can be provided continuously and consistently along the first rotation axis 51 or can be arranged as a plurality of discrete recesses and protrusions positioned along the first rotation axis 51.

[0044] Each rotatable joint is divided into four parts by the first rotation plane and the second rotation plane, and accordingly, each joint body is also divided into four parts. The joint body 4 includes a coupling tendon accommodation part 3 in each part, and the respective coupling tendon accommodation parts 3 of the plurality of joint bodies 4 arranged along the lengthwise direction of the articulated member 1 cooperate with each other to form a channel for extension of the coupling tendon 2, so as to receive the respective coupling tendons 2.

[0045] In some embodiments, the coupling tendon accommodation part 3 includes a straight section 31 and a diverting section 32. The straight section 31 extends parallel to the central axis O of the articulated member 1, and the diverting section 32 connects a straight section 31 belonging to one rotatable joint and another straight section belonging to another rotatable joint in the joint body 4, with the two straight sections extending in a direction symmetrical about the first or second rotation plane. As shown in FIGS. 8-9, a proximal part of the second joint body 42 belongs to the second joint 12, and a distal part thereof belongs to the third joint 13. Both the proximal and distal parts are provided with a straight section 31 extending parallel to the central axis O, while a middle part of the second joint body 42 is provided with a diverting section 32 for connecting a straight section in the proximal part with a straight section in the distal part. The two straight sections are symmetrical about the first or second rotational plane. The same is true for the first and third joint bodies 41, 43. In some other embodiments, two straight sections in the joint body extending along the same axis can communicate with each other, so that the coupling tendon 2 can pass through the articulated member 1 not only in a way transitioning from one straight section to another one via the diverting section 32, but also in an alternate way extending straight from one straight section to another one, thereby enriching the configuration manner of the coupling tendons 2 to be adapted to various motions of the articulated joint.

[0046] As shown in FIGS. 3, 10 and 13, each coupling tendon 2 extends linearly within one of three joint bodies, exchanges its orientation symmetrically with an adjacent coupling tendon about the first rotation plane within another one of the three joint bodies, and exchanges its orientation symmetrically with another adjacent coupling tendon about the second rotation plane within the remaining one of the three joint bodies. Each coupling tendon 2 includes a proximal portion, an intermediate portion and a distal portion received in the straight section 31 of the coupling tendon accommodation part 3, and a transition portion received in the diverting section 32. In the lengthwise direction of the articulated member, the proximal portion transitions to the intermediate portion within one joint body via the transition portion, and the proximal portion extends in a direction symmetrical to the intermediate portion about the first rotation plane. The intermediate portion transitions to the distal portion within another joint body via the transition portion, and the intermediate portion extends in a direction symmetrical to the distal portion about the second rotation plane. Thus, the proximal portion and the distal portion of the coupling tendon 2 are ultimately made diagonally opposite with respect to the central axis O of the articulated member. That is, the distal portion and the proximal portion are located in a plane extending through the central axis O and are distanced equally from the central axis O.

[0047] In particular, as shown in FIGS. 3-4, the first coupling tendon 21 includes a proximal portion 211, an intermediate portion 212 and a distal portion 213 connected in sequence via transition portions 215. The proximal end of the first coupling tendon 211 is secured to the first section 15 of the first joint 11, and the distal end is secured to the second section 16 of the fourth joint 14. The proximal portion 211 extends from the first section 15 of the first joint 11 to the second section 16 of the first joint 11 and then, within the first joint body 41, extends linearly to the first section 15 of the second joint 12. Subsequently, the proximal portion 211 extends to the second section 16 of the second joint 12. Next, a transition portion 215 of the first coupling tendon 21 extends, inside the second joint body 42, from one straight section 31 for receiving the proximal portion 211 to another straight section 31 for receiving the intermediate section 212 via the diverting section 32. The two straight sections 31 are symmetrical with respect to the second rotation plane. The intermediate portion 212 of the first coupling tendon 21 extends from the first section 15 of the third joint 13 to the second section 16 of the third joint 13. A further transition portion 215 of the first coupling tendon 21 extends, inside the third joint body 43, from one straight section 31 for receiving the intermediate portion 212 to another straight section 31 for receiving the distal portion 213 via the diverting section 32. The two straight sections 31 are symmetrical with respect to the first rotation plane. As a result, the proximal and distal portions 211, 213 of the first coupling tendon 21 are diagonally opposite relative to the central axis O of the articulated member 1.

[0048] Similarly, a proximal portion 221 of the second coupling tendon 22 extends from the first section 15 of the first joint 11 to the second section 16 of the first joint 11 and then, within the first joint body 41, extends linearly to the first section 15 of the second joint 12. Subsequently, the proximal portion 221 extends to the second section 16 of the second joint 12. Next, a transition portion 225 of the second coupling tendon 22 extends, inside the second joint body 42, from one straight section 31 for receiving the proximal portion 221 to another straight section 31 for receiving the intermediate portion 222 via the diverting section 32. The two straight sections 31 are symmetrical with respect to the second rotation plane. The intermediate portion 222 of the second coupling tendon 22 extends from the first section 15 of the third joint 13 to the second section 16 of the third joint 13. A further transition portion 225 of the second coupling tendon 22 extends, inside the third joint body 43, from one straight section 31 for receiving the intermediate portion 222 to another straight section 31 for receiving the distal portion 223 via the diverting section 32. The two straight sections 31 are symmetrical with respect to the first rotation plane. As a result, the proximal and distal portions 221, 223 of the second coupling tendon 22 are diagonally opposite relative to the central axis O of the articulated member 1.

[0049] The third and fourth coupling tendons 23, 24 are arranged equivalently to the first and second coupling tendon 21, 22 and will not be detailed here.

[0050] Each coupling tendon 2 passes straight through each of the joints and changes its orientation within two of the three joint bodies 41, 42, 43. Each time the orientation is changed, the coupling tendon 2 exchanges its orientation with an adjacent coupling tendon 2 about one of the first and second rotation planes. Referring to FIGS. 3 and 4, the adjacent first and second coupling tendons 21, 22 (or the third and fourth coupling tendon 23, 24) cross the second rotation plane inside the second joint body 42 to exchange their orientations, respectively. The adjacent first and fourth coupling tendons 21, 24 (or the second and third coupling tendon 22, 23) cross the first rotation plane inside the third joint body 43 to exchange their orientations, respectively.

[0051] That is, each coupling tendon 2 passes straight through each joint and changes direction within some of the joint bodies in two steps. Initially, the coupling tendon 2 is located on one side of one of the first and second rotation planes. In the first step, the coupling tendon 2 moves to the other side of the one of the first and second rotation planes within any joint body. In the second step, the coupling tendon 2 moves to the other side of the other one of the first and second rotation planes within another joint body. The aforementioned two steps can be implemented within any two of the first joint body 41, the second joint body 42, and the third joint body 43. In addition to the configuration shown in FIGS. 3 to 6 where two pairs of coupling tendons 2 pass linearly within the first joint body 41 and exchange orientations within the second joint body 42 and the third joint body 43, the articulated member may also employ a configuration where two pairs of coupling tendons 2 pass linearly within the second joint body 42 and exchange orientations within the first and third joint bodies 41, 43, or a configuration where two pairs of coupling tendons 2 pass linearly within the third joint body 43 and exchange orientations within the first and second joint bodies 41, 42.

[0052] Alternatively, other configurations of the articulated member may be employed. For example, one pair of coupling tendons 2 may exchange their orientations within one of the first joint body 41, the second joint body 42 and the third joint body 43, another pair of coupling tendons 2 may exchange their orientations within another one of the three joint bodies 41, 42 and 43, and two pairs of coupling tendons 2 exchange their orientations within the remaining one of the three joint bodies 41, 42 and 43. Each coupling tendon 2 extends from an initial position located on a first side of the central axis O to a final position located on a second side of the central axis O, by means of orientation exchanges for twice with respect to the first rotation plane and the second rotation plane, wherein the initial and final positions are diagonally opposite to each other. Due to the symmetry of the articulated member's movement, the first joint 11 and the fourth joint 14 are coupled together, and rotation of one of them will cause the other one to rotate the same magnitude of rotation in the same direction. The same is true for the second and third joints 12, 13.

[0053] FIGS. 15-16 show such an example with reference to an articulated member 1'. The articulated member 1' is similar to the articulated member 1 shown in the preceding figures in that the first and third coupling tendons 21, 23 follow exactly the same path through the articulated member 1' as they do through the articulated member 1 shown in the preceding figures. However, the second and fourth coupling tendons 22', 24' follow a different path through the articulated member 1' compared to the second and fourth coupling tendons 22, 24 of the articulated member 1 shown in preceding figures.

[0054] In particular, a proximal portion 221' of the second coupling tendon 22' extends from the first section 15 of the first joint 11 to the second section 16 of the first joint 11. Within the first joint body 41, a transition portion 225' of the second coupling tendon 22' extends from one straight section 31 for receiving the proximal portion 221' to another straight section 31 for receiving the intermediate portion 222' via the diverting section 32. The two straight sections 31 are symmetrical with respect to the first rotation plane. The intermediate portion 222' of the second coupling tendon 22' extends from the first section 15 of the second joint 12 to the second section 16 of the second joint 12. Within the second joint body 42, a further transition portion 225' of the second coupling tendon 22' extends from one straight section 31 for receiving the intermediate portion 222' to another straight section 31 for receiving the distal portion 223' via the diverting section 32. The two straight sections 31 are symmetrical with respect to the second rotation plane. The distal portion 223' extends from the first section 15 of the third joint 13 to the second section 16 of the third joint 13 and then, within the third joint body 43, extends linearly to the first section 15 of the fourth joint 14. Subsequently, the distal portion 223' extends to the second section 16 of the second joint 12 and is secured there. As a result, the proximal and distal portions 221', 223' of the second coupling tendon 22' are diagonally opposite relative to the central axis O of the articulated member 1'. The fourth coupling tendon 24' follows an equivalent path to the second coupling tendon 22' through the articulated member 1' so that its proximal and distal portions 241', 243' are also diagonally opposite relative to the central axis O of the articulated member 1'. Although the joints 11, 12, 13, 14 of the articulated member 1' are coupled to rotate identically to those of the articulated member 1 shown in the preceding figures, a potential advantage of the articulated member 1' is that a region extending longitudinally through the articulated member 1', to one side of the central axis O, is entirely clear of any transition portions. In other words, no coupling tendons 2 change orientation through this eccentric longitudinally extending region of the articulated member 1'. This may provide additional space in the articulated member 1' for auxiliary features such as a lumen and / or sensing devices.

[0055] The first rotation plane and the second rotation plane divide a cross-section of the articulated member 1 into four quadrants. In the embodiment shown in FIGS. 3-4 and 10-11, the first coupling tendon 21 is initially located in the first quadrant, and will be located in the second quadrant after symmetrically exchanging its orientation with the second coupling tendon 22 about the second rotation plane inside the second joint body 42, and be located in the third quadrant after symmetrically exchanging its orientation with the fourth coupling tendon 24 about the first rotation plane inside the third joint body 43. In this case, it is understood that the first coupling tendon 21 transitions in a counterclockwise direction from one quadrant to an adjacent quadrant, eventually arriving at a diagonal position. Similarly, the second coupling tendon 22 is initially located in the second quadrant, and will be located in the first quadrant after exchanging its orientation symmetrically with the first coupling tendon 21 about the second rotation plane inside the second joint body 42, and be located in the fourth quadrant after exchanging its orientation symmetrically with the third coupling tendon 23 about the first rotation plane inside the third joint body 43. In this case, it is understood that the second coupling tendon 21 transitions in a clockwise direction from one quadrant to an adjacent quadrant, eventually arriving at a diagonal position. Likewise, the third coupling tendon 23 and the fourth coupling tendon 24 may be considered as transitioning from one quadrant to an adjacent quadrant in a clockwise, counterclockwise direction, respectively, eventually arriving at a diagonal position.

[0056] One exemplar of the articulated member 1 of the present application follows an "ABBA" configuration, in which two joints B having a rotation axis extending in the same first direction are sandwiched between two joints A having an rotation axis extending in the same second direction. Referring to FIGS. 1-3, for example, the second joint 12 and the third joint 13 rotating about the second rotation axis 52 are sandwiched by the first joint 11 and the fourth joint 14 rotating about the first rotation axis 51.

[0057] The articulated member may have different configurations such as AABB, ABAB as long as the coupling tendons change orientations in the joint body between the two A joints about the first rotation plane, and then change the orientations in the joint body between the two B joints again about the second rotation plane.

[0058] In the ABBA configuration, the articulated member 1 may include 2N rotatable joints and 2N coupling tendons, wherein a rotation axis of the ith joint and a rotation axis of the (2N+ l-i)th joint are parallel to each other and define the ith rotation plane together with the central axis O of the articulated member, wherein N^2 and l^i^N. That is, the joints with the same sequence number counted from a head end and a tail end of the articulated member can rotate about the axes parallel to each other. An angle between any two adjacent rotation planes among the N rotation planes is 180° / N, that is, an angle between the ith rotation plane and the (i+l)th rotation plane is 180° / N.

[0059] Among the 2N rotatable joints, a joint body is consisted of the second section of a proximal joint and the first section of a distal joint in two adjacent rotatable joints, resulting in a total number of (2N-1) joint bodies. Each joint body is divided into 2N parts by N rotation planes, and each part includes a coupling tendon accommodation part. The respective coupling tendon accommodation parts of the plurality of joint bodies arranged along the lengthwise direction of the articulated member cooperate with each other to form a channel for extension of the coupling tendon. Each coupling tendon changes its orientation within N of the (2N-1) joint bodies by bypassing the central axis of the articulated member. In the lengthwise direction of the articulated member, each coupling tendon includes (N+l) linear portions connected sequentially via a transition portion, and each linear portion extends parallel to the central axis O of the articulated member. The mth linear portion extends in a direction symmetric to the (m+l)th linear portion about the mth rotation plane, wherein l^m^N. In the embodiment shown in FIGS. 1-4, N equals to 2. In this case, the articulated member 1 includes four rotatable joints and four coupling tendons, and three linear portions of each coupling tendon are the proximal portion, the middle portion, and the distal portion, respectively.

[0060] In this way, the coupling tendon 2 is deflected 180 / N degrees relative to the central axis O during its transition from the second section 16 of a proximal joint to the first section 15 of a distal joint in two adjacent rotatable joints, and will be deflected 180 degrees relative to the central axis after a full change of orientation within N joints, i.e., arriving at a final position diagonally opposite to the initial position. From the perspective of a cross-section of the articulated member divided into 2N parts by the N rotation planes, a certain coupling tendon transitions from one part to an adjacent part in the clockwise direction, finally arriving at a diagonal position, while two adjacent coupling tendons thereof transition from one part to an adjacent part in the counterclockwise direction, finally arriving at their respective diagonal positions.

[0061] Linear portions 31 of each coupling tendon accommodation part 3 may be equally distanced from two adjacent rotation planes, and any two adjacent linear portions 31 in a circumferential direction of the articulated member 1 within a certain joint body may be equally distanced. In other words, the plurality of coupling tendons 2 received in the coupling tendon accommodation part 3 are evenly spaced apart from each other throughout the articulated member, and are equidistant from the adjacent rotation planes. Accordingly, any one of the linear portions 31 is offset from any one of two adjacent rotation planes thereof by a degree of 180° / N. This ensures that the mutually coupled first and last rotatable joints (and other intermediate joints rotating about the same rotation axis) can rotate at the same rate, and the plurality of coupling tendons 2 can act equally on each rotatable joint of the articulated member to make it rotate about the corresponding rotation axis, thus facilitating the usability and stability of the articulated member.

[0062] In some embodiments, the articulated member 1 further includes a plurality of actuation tendons 6 and a plurality of actuation tendon accommodation parts 7. Each actuation tendon accommodation part 7 extends parallel to the central axis O of the articulated member 1, and each actuation tendon 6 extends through one actuation tendon accommodation part 7. The distal end of the actuation tendon 6 is fixed to the distal end of the articulated member 1, and the proximal end of the actuation tendon 6 is capable of moving along the lengthwise direction of the articulated member relative to the proximal end of the articulated member, as shown in FIGS. 10-11. In operation, the proximal end of the actuation tendon 6 can be pulled to drive the respective rotatable joints to rotate.

[0063] In some embodiments, the number of actuation tendons 6 is the same as the number of coupling tendons 2, and the plurality of actuation tendon accommodation parts 7 are positioned symmetrically about the respective rotation axes. Each actuation tendon 6 is located between two adjacent coupling tendons 2 in the circumferential direction of the articulated member 1. That is, the actuation tendons 6 are provided in pairs about the respective rotation axes inside the articulated member, and the pairs of actuation tendons are operable antagonistically with respect to one another. Referring to FIGS. 6-7 and 10-11, for example, the first and second actuation tendon 61, 62 are located on the second rotation plane and are symmetrically distributed on two sides of the first rotation plane, and the third and fourth actuation tendons 63, 64 are located on the first rotation plane and are symmetrically distributed on two sides of the second rotation plane. The actuation tendon 6 extends from the first section 15 of the first joint 11 along the lengthwise direction of the articulated member to the fourth joint 14, and is finally fixed to the second section 16 of the fourth joint 14. When the actuation tendon 61 or 62 is pulled, the first joint 11 and the fourth joint 14 rotate in the same direction with respect to their respective first rotation axis 51; when the actuation tendon 63 or 64 is pulled, the second joint 12 and the third joint 13 rotate in the same direction with respect to their respective second rotation axis 52.

[0064] By pulling pairs of the actuation tendons 6 the articulated member 1 will bend from a straight state shown in FIG. 10 to a U-shaped state shown in FIG. 12. Referring to FIGS. 10-13, for example, the second actuation tendon 62 at the bottom is located between the first coupling tendon 21 and the third coupling tendon 23, and when the second actuation tendon 62 is pulled toward the proximal side, the length of each coupling tendon 2 required to extend across each joint will change, and accordingly each joint may rotate about its respective rotation axis. Since the distal end of the second actuation tendon 62 is fixed, while the proximal end is free, and the fourth coupling tendon 24 extends straight within the first joint body 41, the fourth coupling tendon 24 will be more exposed at the first and second joints 11, 12. Since the length of each coupling tendon 2 is fixed between the proximal end and the distal end of the articulated member, a change in the length of the fourth coupling tendon 24 required to extend across the first and second joints 11, 12 needs to be balanced by corresponding change in the length within the third and fourth joints 13, 14. The fourth coupling tendon 24 exchanges its orientation with the second coupling tendon 22 about the second rotation plane inside the second joint body 42, and with the first coupling tendon 21 about the first rotation plane inside the third joint body 43. To balance the change in length, the fourth coupling tendon 24 needs to be shortened in the third joint

[0065] 13 and also in the fourth joint 14, thus driving the third joint 13 to rotate about the second rotation axis 52 toward the outside of the paper, while driving the fourth joint

[0066] 14 to rotate downward about the first rotation axis 51. Other coupling tendons 2 will similarly change their length at each joint. As a result, pulling action of the actuation tendon 6 may cause the entire articulated member to bend into a U-shape, as shown in FIGS. 12-13.

[0067] In some embodiments, the articulated member 1 further includes a central channel 9 extending through the articulated member along its central axis O, and a connection line 8 received in the central channel 9, as shown in FIGS. 1 and 6-7. The central passage 9 extends along the central axis O of the articulated member 1, and bypasses the aforementioned coupling tendons 2 and actuation tendons 6. The connection line 8 extends within the central passage 9 for supplying power, fluids, drugs, etc. to the end effector of a robotic surgical system. Since the central channel 9 of the articulated member 1 configured for accommodating the connection lines 8 is not occupied by the coupling tendons 2 and actuation tendons 6, a space for accommodating the connection lines 8 can be ensured, making the articulated member 1 suitable for a wider range of surgical scenarios. In addition, the central channel 9 can be made smaller to reduce the size of the articulated member.

[0068] In a second aspect of the present application, there is provided a surgical instrument 10, as shown in FIG. 14, which includes an articulated member 1 as described above, and an end effector 20 coupled to the articulated member 1. In this embodiment, the end effector 20 is coupled to the second section 16 of the fourth joint 14 and rotates along with the fourth joint 14. The end effector 20 is movable by pulling the actuation tendon 6 to control an attitude of the articulated member, which in turn adjusts an attitude of the end effector 20 to perform certain operations. The connection line 8 may extend from the proximal end to the distal end of the articulated member 1, and finally to the end effector 20 through the central channel 9 of the articulated member 1.

[0069] In some embodiments, as shown in FIG. 14, the end effector 20 includes a fixation part 201 and a manipulation part 202. The fixation part 201 is fixed to the distal end of the articulated member 1, and the manipulation part 202 is connected to the connection lines of the articulated member 1. The manipulation part 202 may be a surgical forceps, etc., for holding and releasing a scalpel. In practice, different types of end effectors 20 can be employed as needed, to achieve specific movements required in surgical procedures.

[0070] The above embodiments are used only to illustrate technical solutions of the present application, not in a limiting way. Despite the detailed description of this application with reference to the foregoing embodiments, it is understood by those of ordinary skill in the art that it is possible to modify the technical solutions set forth in the foregoing embodiments, or to replace some technical features with equivalent ones. Such modifications or replacements do not make the essence of the corresponding technical solutions out of the spirit and scope of the present application, and they should be included in the scope of protection of this application.

Claims

CLAIMS1. An articulated member comprising: a plurality of rotatable joints connected sequentially along a lengthwise direction of the articulated member, each rotatable joint comprising a first section and a second section rotatable relative to each other about a rotation axis perpendicular to a central axis of the articulated member; the second section of a proximal joint and the first section of a distal joint among two adjacent rotatable joints constitutes a joint body, and a plurality of joint bodies are distributed in series along the lengthwise direction between a proximal end and a distal end of the articulated member; and a plurality of coupling tendons each extending through said plurality of joint bodies, with two ends being fixed to the proximal end and the distal end of the articulated member respectively; each coupling tendon extends from the first section of a first rotatable joint along a first extension axis to a first joint body, changes its orientation within at least two of said plurality of joint bodies by bypassing the central axis, and then leaves a last joint body along a second extension axis and is fixed to the second section of a last rotatable joint; wherein the first extension axis and the second extension axis are parallel to and symmetrical about the central axis.

2. The articulated member according to claim 1, wherein each change of orientation of each coupling tendon occurs between two rotatable joints having rotation axes defining a rotation plane with the central axis, the change of orientation occurring along a tendon plane that is perpendicular to the rotation plane.

3. The articulated member according to claim 1 or claim 2, wherein each joint body is configured to conceal the plurality of coupling tendons extending therethrough such that each coupling tendon is concealed within a joint body as the coupling tendon changes orientation.

4. The articulated member according to any one of claims 1 to 3, wherein the proximal end of the articulated member is located at the first section of the first rotatable joint, the distal end of the articulated member is located at the second section of the last rotatable joint, and the first section and the second section in each joint body are secured to each other or formed integrally.

5. The articulated member according to any one of claims 1 to 4, wherein the first rotatable joint and the last rotatable joint are each rotatable about a respective first rotation axis, the first rotation axis intersects the central axis of the articulated memberand defines a first rotation plane together with the central axis, and the first extension axis and the second extension axis are located on two sides of the first rotation plane.

6. The articulated member according to claim 5, wherein two rotatable joints are provided between the first rotatable joint and the last rotatable joint in the lengthwise direction of the articulated member, and are both rotatable about a respective second rotation axis; the second rotation axis intersects with the central axis of the articulated member and defines a second rotation plane together with the central axis; the second rotation plane is perpendicular to the first rotation plane, and the first extension axis and the second extension axis are located on two sides of the second rotation plane.

7. The articulated member according to claim 6, wherein each of the rotatable joints is divided into four parts by the first rotation plane and the second rotation plane; the joint body comprises in each part a coupling tendon accommodation part; the respective coupling tendon accommodation parts of the plurality of joint bodies arranged along the lengthwise direction of the articulated member cooperates with each other to form a channel for extension of the coupling tendon.

8. The articulated member according to claim 7, wherein the coupling tendon accommodation part comprises a straight section extending parallel to the central axis of the articulated member, and a diverting section connecting one straight section belonging to one rotatable joint with another straight section belonging to another rotatable joint in the joint body, wherein said one straight section extending in a direction symmetrical to said another straight section about the first rotation plane or the second rotation plane.

9. The articulated member according to claim 6, wherein each of the coupling tendons extends linearly within one of three joint bodies, exchanges its orientation symmetrically with an adjacent coupling tendon about the first rotation plane within another one of the three joint bodies, and exchanges its orientation symmetrically with another adjacent coupling tendon about the second rotation plane within the remaining one of the three joint bodies.

10. The articulated member according to claim 9, wherein all of four coupling tendons extend linearly within the same one of the three joint bodies.

11. The articulated member according to claim 9, wherein two of four coupling tendons extend linearly within the same one of the three joint bodies and the other two of the four coupling tendons extend linearly within another one of the three joint bodies.

12. The articulated member according to claim 8, wherein each of the coupling tendons comprises a proximal portion, an intermediate portion and a distal portion received in respective straight sections, and a pair of transition portions received in respective diverting sections, wherein the proximal portion transitions to the intermediate portion within one joint body via one of the pair of transition portions, the proximal portion extending in a direction symmetrical to the intermediate portion about the first rotation plane; the intermediate portion transitions within another joint body to the distal portion via the other of the pair of transition portions, the intermediate portion extending in a direction symmetrical to the distal portion about the second rotation plane.

13. The articulated member according to claim 1, wherein the articulated member comprises 2N rotatable joints and 2N coupling tendons, wherein a rotation axis of the ithrotatable joint and a rotation axis of the (2N+ l-i)throtatable joint are parallel to each other and define the ithrotation plane together with the central axis of the articulated member, wherein N^2, and l^i^N; an angle between any two adjacent rotation planes of the N rotation planes is 180° / N.

14. The articulated member according to claim 13, wherein each of the coupling tendons changes its orientation within N of the (2N-1) joint bodies by bypassing the central axis of the articulated member; in the lengthwise direction of the articulated member, each of the coupling tendons comprises (N+l) linear portions connected sequentially via a transition portion, wherein each linear portion extends parallel to the central axis, and the mthlinear portion extends in a direction symmetrical to the (m+ l)thlinear portion about the mthrotation plane, wherein l^m^N.

15. The articulated member according to any one of claims 1 to 14, wherein the articulated member further comprises a plurality of actuation tendon accommodation parts extending parallel to the central axis of the articulated member, and a plurality of actuation tendons each extending through a respective one of the actuation tendon accommodation parts; a distal end of the actuation tendon is fixed to the distal end of the articulated member, and a proximal end of the actuation tendon is movable relative to the proximal end of the articulated member along the lengthwise direction.

16. The articulated member according to claim 15, wherein the number of the actuation tendons is the same as the number of the coupling tendons, and the plurality of actuation tendon accommodation parts are positioned symmetrically about the respective rotation axes; each actuation tendon is located between two adjacent coupling tendons in a circumferential direction of the articulated member.

17. The articulated member according to any one of claims 1 to 14, wherein the articulated member further comprises a central channel extending through the articulated member along the central axis, and a connection line received in the central channel.

18. A surgical instrument comprising an articulated member as claimed in any one of claims 1 to 17, and an end effector coupled to the articulated member.

19. The surgical instrument according to claim 18, wherein the articulated member is an articulated member as claimed in claim 17; the end effector comprises a fixation part fixed to the distal end of the articulated member, and a manipulation part connected with the connection line of the articulated member.

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