Advancing and retreating mechanism of cable and end effector assembly using the same

Abstract

To provide an advancing and retreating mechanism of a cable that enables reliable advancing and retreating of the cable even when a guide part is partially provided with respect to the cable.SOLUTION: An advancing and retreating mechanism of a cable includes: a bending part 23 performing bending and extension; a flexible push-pull cable 11 capable of advancing and retreating at a predetermined stroke while inserting the bending part 23 in an axial direction; a guide part 13 for guiding a part of the push-pull cable 11 in the axial direction outside the bending part 23; and a strength member 15 attached to the push-pull cable 11 at least outside the guide part 13, separated in the axial direction more than the stroke in a state before advancing of the push-pull cable 11 with respect to the bending part 23, and having a higher strength than the push-pull cable 11.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cable advance / retract mechanism used in a robot, a manipulator, or the like, and an end effector assembly using the same. [Background technology]

[0002] A conventional cable advancement / retraction mechanism is, for example, that described in Patent Document 1, which is applied to a surgical stapling device.

[0003] This cable advancement / retraction mechanism includes a flexible tubular shaft and a tubular support shaft, which are bending portions that perform bending and extension, and a flexible closure cable is inserted through these flexible tubular shaft and tubular support shaft.

[0004] The closure cable is guided by a cable support element acting as a guide from the flexible tubular shaft to the tubular support shaft, and the closure cable can be pushed and pulled relative to the flexible tubular shaft, allowing it to advance and retract axially at a predetermined stroke.

[0005] However, there are cases where guide portions such as cable support elements cannot be provided for the entire cable. In such cases, when the cable is pushed in, it may bend and bulge in a direction transverse to the axial direction at the locations where there are no guide portions, making it impossible to reliably move the cable forward and backward. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 7-265323 Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved is that when a guide portion is partially provided for a cable, there is a risk that the cable may not be able to reliably move forward and backward. [Means for solving the problem]

[0008] The present invention provides a cable advancement / retraction mechanism comprising: a bending section that bends and extends; a flexible cable that can be advanced and retreated by a predetermined stroke while being inserted axially through the bending section; a guide section that guides a portion of the cable in the axial direction outside the bending section; and a strength member that is attached to the cable at least outside the guide section and that is spaced apart from the bending section in the axial direction by more than the stroke in a state before the cable advances.

[0009] The present invention also provides an end effector assembly having the above-mentioned cable advance / retract mechanism, comprising an end effector attached to the tip of the bending portion, and the tip of the cable attached to the end effector. [Effects of the Invention]

[0010] According to the present invention, even when guide portions are partially provided for the cable, the cable can be reliably advanced and retracted. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a side view showing a distal end portion of an end effector assembly equipped with a cable advance / retract mechanism according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a side view showing the base end side of the end effector assembly according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing the distal end side of the end effector assembly of FIG. 1 with the end effector attached. [Figure 4] 4 is a cross-sectional view showing the proximal end side of the end effector assembly of FIG. 2. FIG. [Figure 5] FIG. 5 is a cross-sectional view showing a push-pull cable and a strength member used in a cable advance / retract mechanism according to a second embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view showing a push-pull cable, a strength member, and a proximal guide portion used in a cable advance / retract mechanism according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The object of enabling the cable to reliably move forward and backward even when a guide section is partially provided for the cable is achieved by attaching a high-strength strength member to the cable at least outside the guide section that guides the cable.

[0013] The cable advancement / retraction mechanism comprises a bending portion 23, cable 11, a guide portion 13, and a strength member 15. The bending portion 23 is the portion that performs bending and extension. Cable 11 is a flexible member that can be advanced and retreated at a predetermined stroke while being inserted axially through bending portion 23. Guide portion 13 guides a portion of cable 11 in the axial direction outside of bending portion 23. Strength member 15 is a member that is stronger than cable 11 and is attached to cable 11 at least outside of guide portion 13. This strength member 15 is positioned axially away from bending portion 23 by a distance greater than the stroke of cable 11 before cable 11 is advanced.

[0014] The guide portion 13 may include a proximal guide portion 17 that is relatively close to the bending portion 23 and a distal guide portion 19 that is relatively far from the bending portion 23. In this case, the strength member 15 may be located at least between the proximal guide portion 17 and the distal guide portion 19 before the cable 11 is advanced.

[0015] The extension range of the strength member 15 can be set arbitrarily. In one embodiment, the strength member 15 may be attached to the cable 11 so as to extend from outside the guide portion 13 to inside the guide portion 13. When the strength member 15 is provided at least between the proximal guide portion 17 and the distal guide portion 19, it is preferable that the strength member 15 be positioned within the distal guide portion 19 for a length equal to or greater than the stroke.

[0016] The strength member 15 may include an abutment portion 35 that abuts against the guide portion 13 when the cable 11 advances by the stroke. In one embodiment, the abutment portion 35 may be an end portion of the strength member 15 in the axial direction.

[0017] The cable 11 may be composed of a first cable portion 11a and a second cable portion 11b which are separate from each other and located on either side of the strength member 15. In this case, the strength member 15 connects the first cable portion 11a and the second cable portion 11b together in an integrated manner.

[0018] The strength member 15 may have any suitable shape, and may be a cylindrical body in one embodiment. In this case, the strength member 15 is attached to the outer periphery of the cable 11 by caulking.

[0019] The end effector assembly 1, which is equipped with a cable advance / retract mechanism, includes an end effector 7 attached to the tip of the bending portion 23, and the tip of the cable 11 is attached to the end effector 7. [Example]

[0020] [End effector assembly] Fig. 1 is a side view showing a distal end portion of an end effector assembly having a cable advance / retract mechanism according to Example 1. Fig. 2 is a side view showing a proximal end portion of the end effector assembly according to Example 1. Fig. 3 is a cross-sectional view showing the distal end portion of the end effector assembly of Fig. 1 with an end effector provided thereto. Fig. 4 is a cross-sectional view showing the proximal end portion of the end effector assembly of Fig. 2.

[0021] The end effector assembly 1 in FIGS. 1 to 4 is a surgical instrument used in a surgical support robot, a surgical support manipulator, or the like, and includes a shaft 3, a bending structure 5, and an end effector .

[0022] Although a forceps assembly is shown as an example of the end effector assembly 1, it is not limited to a forceps assembly and may be used in other surgical instruments. Furthermore, the end effector assembly 1 can be applied to various devices other than surgical instruments, such as industrial robots and manipulators.

[0023] The shaft 3 is formed in a cylindrical shape and is coupled to a surgical support robot, a surgical support manipulator, or the like so that it can rotate about an axis. A bending structure 5 is provided at the tip of the shaft 3. The shape of the shaft 3 is not particularly limited. The tip of the shaft 3 refers to the end of the shaft 3 that is closest to the end effector 7 in the axial direction. The axial direction is the direction along the axis of the end effector assembly 1.

[0024] An operating wire 9 and a push-pull cable 11, which is the cable of this embodiment, are provided inside the shaft 3. Also provided inside this shaft 3 are a guide portion 13 and a strength member 15, which together with the push-pull cable 11 constitute a part of the advance / retreat mechanism of this embodiment.

[0025] The operating wire 9 and the push-pull cable 11 are pulled out from the base end of the shaft 3. The base end of the shaft 3 refers to the end of the shaft 3 that is far from the end effector 7 in the axial direction. Note that the tip and base ends refer to the ends of each part of the end effector assembly 1 that are close to and far from the end effector 7 in the axial direction, respectively, just like the shaft 3.

[0026] The tip of the operation wire 9 is connected to the bending structure 5 and extends into the shaft 3. The connection to the bending structure 5 is achieved by engaging the end 9a of the operation wire 9 with a movable part 25 (described later) of the bending structure 5 so that it does not slip out toward the base end.

[0027] The operating wire 9 is operated so as to be pulled in the axial direction relative to the base end of the shaft 3, thereby bending the bending structure 5. The operating wire 9 may be any long, flexible member.

[0028] The tip of the push-pull cable 11 is coupled to the end effector 7. The push-pull cable 11 extends in the axial direction from the end effector 7 and passes through the bending structure 5 and the shaft 3, including a bending portion 23 described later.

[0029] The push-pull cable 11 can be moved forward and backward in the axial direction by a predetermined stroke by being pushed and pulled in the axial direction relative to the base end of the shaft 3. The push-pull cable 11 operates the end effector 7 by moving forward and backward.

[0030] This push-pull cable 11 only needs to have flexibility to follow the bending of the bending portion 23 of the bending structure 5, and can be an appropriate long member such as a twisted wire, a single wire, an articulated rod, a chain, a string, a thread, a rope, etc. The flexibility of the push-pull cable 11 refers to the ease with which it can be deformed to bend its axis, and is not limited to being determined by the material, but may also be determined by a hinge such as the above-mentioned articulated rod.

[0031] The guide portion 13 guides a portion of the push-pull cable 11 in the axial direction outside the bending portion 23. The guide portion 13 of this embodiment also guides the operating wire 9 in the axial direction. The guide portion 13 is composed of a proximal guide portion 17 that is relatively close to the bending portion 23 and a distal guide portion 19 that is relatively far from the bending portion 23.

[0032] Although the guide portion 13 includes two guide portions, the proximal guide portion 17 and the distal guide portion 19, it may include only one of the proximal guide portion 17 or the distal guide portion 19. It may also include three or more guide portions.

[0033] The proximal guide portion 17 is attached to the tip of the shaft 3. The proximal guide portion 17 is configured to be cylindrical overall, and includes a small diameter portion 17a with a relatively small outer diameter and a large diameter portion 17b with a relatively large outer diameter. The small diameter portion 17a is fitted into the shaft 3, and the large diameter portion 17b abuts against the tip of the shaft 3.

[0034] The proximal guide portion 17 has a through hole 17c on its inner periphery and a radially recessed groove 17d on its outer periphery. The through hole 17c and the groove 17d extend over the entire proximal guide portion 17 in the axial direction.

[0035] The push-pull cable 11 is inserted through the through-hole 17c in the axial direction. With this insertion, the proximal guide portion 17 guides the push-pull cable 11 in the axial direction. The operation wire 9 is inserted through the groove 17d in the axial direction. With this insertion, the operation wire 9 is guided in the axial direction.

[0036] The distal guide portion 19 is attached to the base end of the shaft 3. The distal guide portion 19 is configured to have a cylindrical shape as a whole, similar to the proximal guide portion 17. However, the axial dimension of the distal guide portion 19 is smaller than that of the proximal guide portion 17.

[0037] The distal guide portion 19 has a small diameter portion 19a with a relatively small outer diameter and a large diameter portion 19b with a relatively large outer diameter, and the small diameter portion 19a is fitted into the shaft 3 while the large diameter portion 19b is abutted against the base end of the shaft 3.

[0038] The distal guide portion 19 has a through-hole 19c extending over the entire axial direction on its inner and outer peripheries, and a radially recessed groove 19d. The push-pull cable 11 is inserted and guided through the through-hole 19c in the axial direction. The operating wire 9 is inserted and guided through the groove 19d in the axial direction.

[0039] Between the distal guide portion 19 and the proximal guide portion 17, the push-pull cable 11 and the operating wire 9 are not guided but are exposed inside the shaft 3. A strength member 15 is attached to the push-pull cable 11 in at least this portion.

[0040] That is, the strength member 15 is attached to the push-pull cable 11 at least outside the guide portion 13. The strength member 15 is made of a material having higher strength than the push-pull cable 11. High strength means that the strength member 15 is less susceptible to deformation such that its axis is curved than the push-pull cable 11.

[0041] The shape and material of the strength member 15 are not critical as long as it is less susceptible to deformation such that its axis is curved than the push-pull cable 11. For example, the strength member 15 may have any appropriate shape, such as a cylindrical body, a rod-like body, or a plate-like body.

[0042] In this embodiment, the strength member 15 is a cylindrical body made of a metal such as stainless steel. The strength member 15 is attached to the push-pull cable 11 that passes through the inside of the strength member 15 by crimping. The strength member 15 may also be attached to the push-pull cable 11 by other methods such as welding.

[0043] The strength member 15 extends from the base end region to the tip end region of the shaft 3, and is located within the distal guide portion 19 at the base end region of the shaft 3 and within the proximal guide portion 17 at the tip end region of the shaft 3.

[0044] As a result, before the strength member 15 advances to the bending portion 23, it is positioned at least between the proximal guide portion 17 and the distal guide portion 19. Note that the strength member 15 may be positioned only between the proximal guide portion 17 and the distal guide portion 19.

[0045] In this embodiment, the strength member 15 is located within the distal guide portion 19 in the base end region of the shaft 3, over a length equal to or greater than the stroke. The base end of the strength member 15 is positioned biased toward the tip end relative to the base end of the distal guide portion 19. Therefore, a portion of the push-pull cable 11 is exposed within the distal guide portion 19 and not covered by the strength member 15. In this portion, a gap equal to the thickness of the strength member 15 is formed between the distal guide portion 19 and the push-pull cable 11.

[0046] The tip of the strength member 15 is positioned closer to the base end than the tip of the proximal guide portion 17. As a result, the strength member 15 is positioned at a distance in the axial direction that is greater than the stroke before the push-pull cable 11 advances relative to the bending portion 23.

[0047] In this embodiment, before the push-pull cable 11 advances, the strength member 15 is spaced apart from the base 21 (the tip of the proximal guide part 17) of the bending structure 5 including the bending part 23 by the stroke of the push-pull cable 11. Therefore, within the proximal guide part 17, a part R of the push-pull cable 11 that can advance into the bending structure 5 by the stroke is exposed outside the strength member 15. At this part R, a gap equal to the thickness of the strength member 15 is formed between the distal guide part 19 and the push-pull cable 11.

[0048] The bending structure 5 has a joint function and is a part that enables bending and extension in the end effector assembly 1. The bending structure 5 of this embodiment includes a base portion 21, a bending portion 23, a movable portion 25, and a core material 27.

[0049] The base 21 functions as a base for the bending portion 23 that receives the base end of the bending portion 23. The base 21 is a columnar body, particularly a cylindrical body, formed from resin, metal, or the like. In this embodiment, the base end of the axial direction of the bending portion 23 is attached to the base 21 by welding or the like. However, it is also possible for only one end of the bending portion 23 to abut against the base 21. Furthermore, the material, shape, and structure of the base 21 can be freely set depending on the device to which the bending structure 5 is applied.

[0050] The base 21 is attached to the tip of the shaft 3 via the proximal guide portion 17. The base 21 can be fixed to the proximal guide portion 17 by an appropriate method such as welding. The base 21 has an axial through-hole 21a. The base 21 also has an insertion hole (not shown) around the through-hole 21a for inserting the operating wire 9.

[0051] The bending portion 23 is formed by stacking a plurality of wave washers in the axial direction and maintaining the stacked state by welding, etc. The tip of the bending portion 23 moves relative to the base end received by the base portion 21 by bending and stretching.

[0052] The bending portion 23 is not particularly limited as long as it can be bent and extended, and may be a coil spring, a bellows, etc. At the tip of the bending portion 23, a movable portion 25 is provided.

[0053] The movable part 25 is attached to the tip of the bending part 23 and functions as the base of the end effector 7. The movable part 25 is a columnar body, particularly a cylindrical body, made of resin, metal, or the like. In this embodiment, the movable part 25 is disposed on the tip of the bending part 23 and attached to the tip of the bending part 23 by welding or the like.

[0054] However, the movable part 25 may simply come into contact with the tip of the bending part 23. Furthermore, the movable part 25 only needs to be able to receive the tip of the bending part 23, and the material, shape, and structure can be freely set depending on the device to which the bending structure 5 is applied.

[0055] The movable part 25 of this embodiment has an axial through-hole 25a. The axial thickness of this movable part 25 varies in the circumferential direction. An insertion hole (not shown) for inserting the operation wire 9 is provided in each of the portions of the movable part 25 where the thickness varies.

[0056] The core material 27 is a member that can bend and stretch together with the bending portion 23. In this embodiment, the core material 27 is a multiple coil spring, particularly a double coil spring. However, the core material 27 can also be a tightly closed coil spring, a flexible cylindrical body, or the like.

[0057] The multiple coil spring is arranged such that one winding portion of at least two coil springs is fitted between the other winding portion, thereby making it possible to suppress compression of the bent portion 23. Note that the multiple coil spring may also be one that uses three or more coil springs.

[0058] The axial ends of the core member 27 are attached by welding or the like to the through holes 21a and 25a of the base member 21 and the movable member 25, respectively. A hole 27a is defined on the inner periphery of the core member 27. The push-pull cable 11 is inserted through this hole 27a.

[0059] The end effector 7 is a forceps and includes a base 29, a pair of jaws 31, a jaw holder 33, and the like.

[0060] The base 29 is attached to the movable portion 25 of the bending structure 5. A pair of jaws 31 are supported on the base 29.

[0061] The jaws 31 are rotatably supported on the base 29 and can open and close relative to each other. The end effector 7 of this embodiment can grip a suture or the like by closing the jaws 31. These jaws 31 can be opened and closed by a jaw holder 33.

[0062] The jaw holder 33 is a member that is coupled to both of the pair of jaws 31 so as to be rotatable relative to each other and is capable of reciprocating relative to the base 29. The reciprocating movement of the jaw holder 33 causes the pair of jaws 31 to open and close.

[0063] The reciprocating movement of the jaw holder 33 is performed by the stroke of the push-pull cable 11. In this embodiment, the jaw holder 33 has a connecting tubular portion 33a, and the tip of the push-pull cable 11 is inserted into this tubular portion 33a and connected by welding or the like.

[0064] [Cable advance / retract] In such an end effector assembly 1, the push-pull cable 11 is operated to push and pull outside the shaft 3 in order to open and close the jaws 31.

[0065] When opening the jaws 31, before the push-pull cable 11 has advanced, the push-pull cable 11 is pushed in from the base end of the shaft 3. This causes the push-pull cable 11 to advance by a predetermined stroke toward the tip of the end effector assembly 1.

[0066] When the push-pull cable 11 is advanced, the push-pull cable 11 is guided by the guide portion 13, and the posture is maintained by the strength member 15 outside the guide portion 13. Therefore, the push-pull cable 11 can be reliably advanced.

[0067] At this time, the portion R of the push-pull cable 11 enters the bending structure 5. Since the strength member 15 is not provided in this portion R, the influence on the flexibility of the bending structure 5 is suppressed.

[0068] When the push-pull cable 11 advances in this manner, the jaw holder 33 of the end effector 7 advances, causing the jaws 31 to perform an opening operation.

[0069] On the other hand, when closing the jaw 31, after the push-pull cable 11 has advanced, the push-pull cable 11 is pulled out from the base end of the shaft 3. This causes the push-pull cable 11 to retract by a predetermined stroke toward the base end of the end effector assembly 1.

[0070] Even when the push-pull cable 11 is retracted, the push-pull cable 11 is guided by the guide portion 13, and the posture is maintained by the strength member 15 outside the guide portion 13. Therefore, the push-pull cable 11 can be reliably retracted.

[0071] The retraction of the push-pull cable 11 causes the retraction of the jaw holder 33 of the end effector 7. In response to the retraction of the jaw holder 33, the jaws 31 of the end effector 7 close and perform an operation.

[0072] Therefore, in this embodiment, even if the guide portion 13 is partially provided for the push-pull cable 11, the push-pull cable 11 can be reliably advanced and retracted.

[0073] As described above, the cable advancement / retraction structure of this embodiment comprises the bending section 23 that bends and extends, the flexible push-pull cable 11 that can advance and retract a predetermined stroke while being inserted axially through the bending section 23, the guide section 13 that guides a portion of the push-pull cable 11 in the axial direction outside the bending section 23, and the strength member 15 that is attached to the push-pull cable 11 at least outside the guide section 13 and is spaced apart from the bending section 23 in the axial direction by more than the stroke in the state before the push-pull cable 11 advances, and has greater strength than the push-pull cable 11.

[0074] Therefore, in this embodiment, even if the guide portion 13 is partially provided for the push-pull cable 11, the push-pull cable 11 can be reliably moved forward and backward, while the strength member 15 is prevented from entering the bending portion 23, thereby suppressing the impact on the flexibility of the bending portion 23.

[0075] The guide portion 13 has a proximal guide portion 17 that is relatively close to the bending portion 23 and a distal guide portion 19 that is relatively far from the bending portion 23, and the strength member 15 is located at least between the proximal guide portion 17 and the distal guide portion 19 before the push-pull cable 11 is advanced.

[0076] Therefore, while the push-pull cable 11 is guided on both sides in the axial direction, the posture of the middle part of the push-pull cable 11 in the axial direction is maintained, and the push-pull cable 11 can be moved forward and backward more reliably.

[0077] In this case, it is preferable that the strength member 15 is positioned within the distal guide section 19 by a length equal to or greater than the stroke before the push-pull cable 11 is advanced. If the strength member 15 is attached to the push-pull cable 19 so as to extend from the outside of the guide section 13 to the inside of the guide section 13, as in this embodiment, the push-pull cable 11 can be advanced and retreated more reliably.

[0078] The portion R of the push-pull cable 11 where the strength member 15 is not provided is preferably guided by the guide portion 13, but may be located outside the guide portion 13.

[0079] The strength member 15 of this embodiment is a cylindrical body and is attached to the outer periphery of the push-pull cable 11 by caulking, so that it can be easily attached to the push-pull cable 11.

[0080] The end effector assembly 1 having such a reciprocating structure includes an end effector 7 attached to the tip of the bending portion 23 , and the tip of the push-pull cable 11 is attached to the end effector 7 .

[0081] Therefore, the end effector 7 can be reliably operated through the reliable advancement and retraction of the push-pull cable 11. [Example]

[0082] 5 is a cross-sectional view showing a push-pull cable and a strength member used in a cable advance / retract mechanism according to Example 2 of the present invention. Note that Example 2 has a basic configuration in common with Example 1, and therefore the same reference numerals are used for corresponding components and redundant explanations will be omitted.

[0083] In Example 2, the push-pull cable 11 is divided into a first cable portion 11a and a second cable portion 11b, which are connected by a strength member 15. The first cable portion 11a and the second cable portion 11b are separate elongated members located on either side of the strength member 15.

[0084] The base end of the first cable portion 11a is inserted into and joined to the tip of the strength member 15. The first cable portion 11a and the strength member 15 are joined by crimping. The tip of the second cable portion 11b is inserted into and joined to the base end of the strength member 15. This joining is also done by crimping.

[0085] The first cable portion 11a and the second cable portion 11b are located at the tip and part of the base end inside the strength member 15, and the first cable portion 11a and the second cable portion 11b are not located in other parts, leaving space. However, the first cable portion 11a and the second cable portion 11b may be located throughout the strength member 15.

[0086] In the second embodiment, the same effects as those of the first embodiment can be achieved. [Example]

[0087] 6 is a cross-sectional view showing a push-pull cable, a strength member, and a guide part used in a cable advance / retract mechanism according to Example 3 of the present invention. Note that Example 3 has a basic configuration in common with Example 1, and therefore the same reference numerals are used for corresponding components and redundant explanations will be omitted.

[0088] In the third embodiment, before the push-pull cable 11 is advanced, the strength member 15 includes an abutment portion 35 that abuts against the guide portion 13 when the push-pull cable 11 is advanced by the stroke.

[0089] In this embodiment, the abutting portion 35 is the axial tip of the strength member 15. An abutted portion 36 that protrudes radially inward is formed inside the through hole 17c of the proximal guide portion 17. The abutting portion 35 of the strength member 15 abuts against this abutted portion 36.

[0090] In addition, the abutting portion 35 can be configured by a protrusion or the like provided on the outer periphery of the strength member 15 in the structure of Example 1. Also, in the structure of Example 1, the outer diameter of the strength member 15 can be partially increased, and this portion with the increased outer diameter can be used as the abutting portion 35. Furthermore, an abutted portion 36 can also be provided inside the through hole 19c of the distal guide portion 19.

[0091] In this embodiment 3, it is possible to achieve the same effects as in embodiment 1. Furthermore, in this embodiment, the abutting portion 35 can prevent the push-pull cable 11 from advancing beyond the stroke, thereby preventing damage to the advancing / retracting mechanism and the end effector assembly. [Explanation of symbols]

[0092] 1 End effector assembly 7 End Effector 11 Push-pull cable 13 Guide section 15 Strength members 17 Proximal guide part 19 Distal guide part 11a First cable section 11b Second cable section 35 Contact part

Claims

1. A flexion portion that performs flexion and extension; a flexible cable that can be advanced and retreated by a predetermined stroke while being inserted through the bent portion in the axial direction; a guide portion that guides a portion of the cable in the axial direction outside the bending portion; a strength member that is attached to the cable at least outside the guide portion and that is spaced apart from the bent portion in the axial direction by more than the stroke in a state before the cable advances; and A cable advance / retract mechanism equipped with the

2. The cable advancement / retraction mechanism of claim 1, The guide portion includes a proximal guide portion that is relatively close to the bending portion and a distal guide portion that is relatively far from the bending portion, The strength member is located at least between the proximal guide portion and the distal guide portion before the cable is advanced. Cable advance / retract mechanism.

3. The cable advancement / retraction mechanism according to claim 1 or 2, The strength member is attached to the cable so as to extend from the outside of the guide portion to the inside of the guide portion. Cable advance / retract mechanism.

4. The cable advancement / retraction mechanism of claim 2, The strength member is located within the distal guide portion by a length equal to or greater than the stroke. Cable advance / retract mechanism.

5. The cable advancement / retraction mechanism according to claim 1 or 2, The strength member includes a contact portion that contacts the guide portion when the cable advances by the stroke. Cable advance / retract mechanism.

6. The cable advancement / retraction mechanism of claim 5, The abutment portion is an end portion of the strength member in the axial direction and abuts against an end portion of the guide portion in the axial direction. Cable advance / retract mechanism.

7. The cable advancement / retraction mechanism of claim 1, The cable is composed of a first cable portion and a second cable portion that are separate from each other and are located on both sides of the strength member, The strength member integrally connects the first cable portion and the second cable portion. Cable advance / retract mechanism.

8. The cable advancement / retraction mechanism according to claim 1 or 2, The strength member is a cylindrical body and is attached to the outer periphery of the cable by crimping. Cable advance / retract mechanism.

9. An end effector assembly equipped with the cable advancement / retraction mechanism of claim 1 or 2, an end effector attached to a tip of the bending portion; The cable has a tip attached to the end effector. End effector assembly.

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