JP2000023908A - Articulated curving mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge a working diameter of an articulated curving mechanism constituting the curved portion of an endoscope and to achieve a reduction in tension of a wire cable, particularly to reduce the diameter of the end of the endoscope. SOLUTION: In an articulated curving mechanism for use in an endoscope, etc., the position of a wire guide 35 guiding a wire cable 36 is circumferentially offset by 45 deg. with respect to a position where connecting pieces 21, 22 are connected by a rivet 25 on the inner periphery side of an intermediate element 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-joint bending mechanism, and more particularly to a multi-joint mechanism in which a plurality of emerents are alternately rotatably connected about axes orthogonal to each other, and are bent by being pulled by a wire cable. The present invention relates to a joint bending mechanism.

[0002]

2. Description of the Related Art An endoscope is used for observing a part of a living body which cannot be observed by direct visual observation. Such an endoscope has an operation unit as described in, for example, Japanese Patent Application Laid-Open No. 8-280606, and by manually operating a handle provided on the operation unit, a distal end side is provided. The bending portion is bent in a desired direction, and the observation site can be observed through an objective optical system inside the distal end provided on the distal end side of the bending portion.

[0003] Such endoscopes are widely used for diagnosing the properties of various parts of the human body. For example, gastric endoscopes include a conventional gastric camera type endoscope and a type incorporating a camera. Also, a fiberscope type endoscope that can be photographed by a hand-held camera is used.

FIGS. 11 to 13 show the structure of a conventional bending portion used in such an endoscope. As shown in FIGS. 11 and 12, the curved portion is composed of a tip element 4 and a plurality of intermediate elements 1, which are rotatably connected by rivets 3 and which aim the tip element 4 in a desired direction. Of the element 1
Are guided by a wire guide 5 provided on the inner peripheral portion of.

[0005] As shown in FIG.
A pair of connecting pieces 2 are provided at one end thereof so as to face each other at a position shifted by 180 ° in the circumferential direction, and a pair of opposite ends are provided so as to face each other with a phase shift of 90 °. Are connected to each other. Each connecting piece 2 is provided with a connecting hole through which the rivet 3 is inserted. Also, on the inner peripheral surface of the intermediate element 1, 2
The wire guides 5 are fixed. Wire guide 5
Is to restrain the wire cable 6 while guiding it.

Here, the phase of the plurality of intermediate elements 1 is set to 9
The intermediate element 1 is connected by the rivets 3 sequentially using the connecting pieces 2 so as to be rotated by 0 °. The tip element 4 is rotatably connected to the tip of the intermediate element 1. The four wire cables 6 passing through the intermediate element 4 are linearly guided by the wire guides 5 which are shifted by 90 ° in the circumferential direction, and are fixed to the tip element 4.

Accordingly, when the wire cable 6 is pulled, the articulated bending mechanism bends so that the pulled wire cable 6 is on the inside in order to shorten the pulled wire cable 6.

[0008]

In particular, as shown in FIG. 13, since the wire guide 5 and the wire cable 6 are in the same phase position in the circumferential direction as the rivet 3, the connection piece 2 inside the overlap is provided. Inside surface and rivets 3
Cable 6 with head or crimped projection
Need to avoid interference. For this, wire guide 5
Must be disposed on the inner peripheral side of the connecting piece 2 or the inner diameter of the wire guide 5 needs to be increased.

However, in an endoscope whose distal end can be bent in four directions, the outer diameter of the distal end is about 9 to 10 mm for a medical upper digestive tract and is about 9 to 10 mm for a lower digestive tract. Those having a diameter of 12 to 13 mm are widely used. In order to improve the insertability of the distal end portion of the endoscope into the body cavity and reduce the burden on the patient, it is desired to further reduce the diameter without reducing the function such as the forceps channel diameter.

In such a situation, for example, FIG.
As shown in the figure, in a thick tube 7 or the like, it is difficult to enter the space between the adjacent wire guides 5, and a large dead space 8 is generated in the cross section. As a result, if it is attempted to reduce the diameter of the distal end portion, the tube 7 and other necessary members cannot be accommodated, thereby causing a problem that the reduction in diameter is hindered or the function needs to be reduced. One cause of such a problem results from the relatively large diameter wire guide 5 disposed inside the connection piece 2 of the intermediate element 1 as described above.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a multi-joint bending mechanism in which an internal space is not particularly reduced by a wire guide.

[0012]

According to the present invention, a plurality of elements are alternately rotatably connected about axes orthogonal to each other, and are inserted into a wire guide provided on the inner peripheral side of the elements. In the articulated bending mechanism configured to bend by pulling the wire cable, the wire guide is arranged at a position shifted in a circumferential direction with respect to an axis serving as a rotation center of the element. The present invention relates to a multi-joint bending mechanism.

[0013] The wire guide may be circumferentially offset by about 45 ° with respect to an axis which is a center of rotation of the element. Further, a bending portion of the endoscope may be formed by a plurality of elements that are connected to each other so as to bendable.

According to another aspect of the present invention, there is provided an element having a pair of connecting pieces provided at both ends thereof in a state of being shifted by 180 ° in the circumferential direction, and further having a phase of the connecting pieces at both ends shifted from each other by 90 °, and a plurality of elements. Connecting means for sequentially and rotatably connecting the connecting pieces, a guide provided at a position shifted from the connecting piece by approximately 45 ° in the circumferential direction of the element, and the plurality of elements guided by the guide. And a traction member for bending the joint.

[0015] A connection hole may be formed in each of the connection pieces of the element, and the connection hole may be rotatably connected by a rivet or a pin. Further, the guide may be fixed to an inner peripheral surface of the element.

According to a preferred aspect of the present invention, in a multi-joint bending mechanism used in an endoscope, a circumferential phase of a position of a wire guide for guiding a wire cable while restraining the same is adjusted by a position of a connecting means serving as a rotation fulcrum. And 45 ° in the circumferential direction. Such a bending mechanism is particularly suitably used for a bending portion of a wire cable pulling type endoscope whose tip is directed in a desired direction.

According to this aspect, the dead space in the intermediate element can be reduced by shifting the phase in the circumferential direction of the position where the wire cable passes by 45 °, so that a large holding force in the element is secured. can do. Therefore, it is possible to further reduce the diameter of the multi-joint bending mechanism of the bending portion of the endoscope for which the reduction in diameter is required. Also, compared to the conventional method, it is possible to increase the distance from the center to the wire, and it is possible to require less wire tension when generating a bending moment required for such a bending mechanism. .

[0018]

FIG. 1 shows an entire configuration of an endoscope according to an embodiment of the present invention. The endoscope includes a distal end portion 11 having an objective optical system therein, A bending portion 12 that can bend so that the tip portion 11 is directed in a predetermined direction.
, A flexible portion 13 that is flexible and inserted into a living body, and an operation portion 15. Further, a universal cord 16 for guiding light, water, air, and power from a power supply unit is connected to the operation unit 15.

The distal end portion 11 is provided with a solid-state imaging device for observing a target portion through an objective lens built therein, and is introduced into the body, and is used for photographing the target portion and forceps from the suction port. The treatment is performed remotely by operation. And such a tip part 11 is attached to the tip part of the curved part 12.

A bendable portion 12 is provided on the proximal end side adjacent to the distal end portion 11 and has a function of following a change in camera angle. Further, the proximal end side of the curved portion 12 is connected to the flexible portion 13 so as to guide the distal end portion 11 to a target portion. An operating portion 15 is provided on the proximal end side of the flexible portion 13. By rotating the operating handle 17 of the operating portion 15, the bending portion 12 is moved up and down or through a built-in wire cable. It is designed to bend left and right.

Next, the structure of the bending portion 12 will be described with reference to FIGS. As shown in FIG. 3, the bending portion 12 includes a tip element 30, a plurality of intermediate elements 20, a root element 31, rivets 25 rotatably connecting these elements, a wire cable 36 for providing a bending driving force,
It comprises a wire guide 35 for guiding the wire cable 36 while restraining it.

The intermediate element 20 is, as shown in FIG.
A pair of connection pieces 21 facing each other is formed at one end, and a pair of connection pieces 22 are provided at the other end with a phase shift of 90 ° with respect to this. Here, the interval between the pair of connecting pieces 21 is smaller than the interval between the connecting pieces 22 at the other end by twice the plate thickness of the connecting pieces 21 and 22. Connection holes 23 and 24 for connection by rivets 25 are formed in the connection pieces 21 and 22, respectively.

On the inner peripheral surface of the intermediate element 20, a pair of wire guides 35 for one of the intermediate elements 20 is provided at a position shifted by 45 ° from the pair of connection pieces 22 having a large interval. Fixed by the way.
Such a wire guide 35 guides the wire cable 36 while restraining it.

Here, the phases of the plurality of intermediate elements 20 are rotated by 90.degree.
The intermediate elements 20 are alternately rotatably connected about axes perpendicular to each other by inserting narrow connecting pieces 21 inside the two and overlapping them, and crimping the connecting holes 23 of these connecting pieces 21 and 22 through rivets and caulking. Is done. Further, a tip element 30 is connected to one end of the connection body of the intermediate element 20, and a root element 31 is connected to the other end by a rivet 25 in a rotatable manner. And four wire cables 36 are inserted through the inside of such a curved part. The wire cable 36 is linearly inserted through a wire guide 35 having a different phase position every 90 ° of the intermediate element 20, and the distal end of the wire cable 36 is fixed to the distal element 30.

When the wire cable 36 is pulled while the root element 31 is fixed, the articulated bending mechanism is arranged such that the pulled wire cable 36 is on the inside in order to shorten the drawn wire cable 36. Curved.

As described above, a major feature of the bending portion 12 of the present embodiment is that the position of the wire guide 35 provided in the intermediate element 20 is shifted by 45 ° in the circumferential direction with respect to the connection piece 22. It was done. Here, the direction in which the wire guide 35 is shifted is not necessarily the direction shown in FIG. 4, but may be shifted by 45 ° in the opposite direction. However, the shifting direction needs to be common to all the elements 20. As the phase of the wire guide 35 is shifted by 45 °, the position of the wire cable 36 is also restrained by the wire guide 35 at a position shifted by 45 °.

By displacing the wire guide 35 for guiding the wire cable 36 in the circumferential direction by 45 °, FIG.
As shown in FIG. 7, the diameter of the wire guide 35 can be made smaller than that of the conventional one. Also, the relatively thick tube 40 and other connecting members 41 can be brought closer to the inner edge of the intermediate element 20 without interfering with the wire guide 35. This increases the space for storing the contents such as the tube 40 and the connecting member 41, which cannot be stored in the conventional technology. In addition, the dead space 42 is much smaller than before.

A major feature of the present embodiment is that the phase of the wire guide 35 through which the wire cable 36 is inserted is shifted by 45 ° with respect to the conventional one, whereby the connection pieces 21 and 22 and the rivet 25 are shifted toward the inner diameter side. And interference with the wire cable 36 is avoided. With such a structure, the diameter of the wire guide 35 can be made smaller, and the wire cable 36 and the wire guide 35 can be arranged on the outer peripheral side as compared with the related art.

The operation unit 1 shown in FIG.
When the operation knob 17 of FIG. 5 is rotated and pulled, the operation knob 17 is rotated in synchronization with the rotation support shafts in two directions orthogonal to each other, so that the rotation is substantially centered on the axis perpendicular to the phase direction where the wire cable 36 is virtually located. Is performed as if there is a rotation fulcrum. In addition, the magnitude of the bending moment generated in the bending mechanism is equal to the case where the position of the wire cable 36 is not offset if the tension of the wire cable 36 is the same. This will be described with reference to FIGS.

First, as shown in FIG. 5, a moment vector having a direction in which the right-handed screw advances when the right-handed screw is turned in the rotation direction and having a length proportional to the magnitude of the moment is defined.

Next, the distance from the center O of the intermediate element 20 to the wire cable 36 shown in FIG. 6 is represented by r, the tension acting on the wire cable 36 is represented by F, and the rotation fulcrum axis of the rivet 25 is represented by P axis and Q axis. . If the wire cable 3
If the phase through which 6 passes is on the same P axis or Q axis as before,
A rotational moment having a magnitude of rF acts around the Q axis or the P axis. Here, as shown in FIG. 6, it is assumed that a tension F is applied to the wire cable 36 positioned at an angle of 45 ° with respect to the P axis from the upper side to the lower side perpendicular to the plane of the drawing. Moment vector ¯ ¯ M _P generated in the P axis and Q axis in this case, the M _Q magnitude M _P, M _Q becomes _{M P = M Q = rF /} √2 ¯ ¯. Also each moment vector M _P, the direction of the M _Q, the Q-axis right direction, and P on the axis.

As shown in FIG. 7, an R axis, which is a virtual rotation fulcrum axis, is defined on the same plane as the P axis and the Q axis in a direction forming an angle of 90 ° with respect to the phase of the wire cable 36. The ¯ ¯ ¯ 2 one time rotational moment vector M _P, the resultant vector M _R of M _Q becomes R-axis upper right 4 ¯ 5 ° direction, magnitude M _R of M _{R is, M R = √2M P = √2M} Q = RF. That is, a moment having the same magnitude as the magnitude rF of the bending moment generated when the position of the wire guide 35 is not offset is generated here. That is, according to the bending mechanism according to the present embodiment, it is not necessary to apply a larger tension to the wire cable 36 than in the related art. That is, the bending moment of bending with the same wire tension does not decrease.

This means that, as shown in FIG.
A multi-joint bending mechanism using the 1.3 mm intermediate element 20 was prototyped, and four wire cables 36 were inserted therein, and the position of the wire guide 35 for guiding these wire cables 36 was changed in the circumferential direction. It has also been confirmed by an experiment performed using an articulated bending mechanism shifted by 45 °.

The results of this experiment are shown in Table 1 below.

[0035]

[Table 1]

Next, another embodiment will be described with reference to FIGS. 9 and 10. FIG. In this embodiment, the intermediate element 2
The wire guide 35 is formed integrally with the wire guide 35. That is, 45 ° in the circumferential direction with respect to the connection piece 22
At a shifted position, the intermediate element 20 is squeezed and protruded inward, so that a wire guide 35 having a substantially semicircular arc shape is integrally formed.

According to such a configuration, the wire guide 3
Although the wire cable 36 passing through the inside of the wire 5 is exposed on the outer surface of the intermediate element 20 at the portion of the wire guide 35, there is no particular problem because the distance is very short. Then, since it is not necessary to fix the wire guide 35 formed of a separate member to the intermediate element 20 by a method such as brazing, it is possible to provide a multi-joint bending mechanism with lower cost.

[0038]

As described above, according to the present invention, a plurality of elements are alternately rotatably connected about axes orthogonal to each other, and are inserted into a wire guide provided on the inner peripheral side of the elements. In a multi-joint bending mechanism configured to bend by pulling an existing wire cable, a wire guide is arranged at a position shifted in a circumferential direction with respect to an axis serving as a rotation center of the element.

Therefore, according to such a configuration, the wire cable can be inserted at a position shifted from the connection position of the element, thereby preventing the wire cable and the wire guide from interfering with the connection mechanism. .

According to the configuration in which the wire guide is displaced by about 45 ° in the circumferential direction with respect to the axis serving as the rotation center of the element, it is possible to generate the same bending moment with substantially the same wire tension as in the related art. And the bending moment is not reduced.

According to the configuration in which the bending portion of the endoscope is formed by a plurality of elements that are bendably connected to each other, a large space is required for inserting other members such as a tube and a connecting member. An endoscope provided with a curved portion capable of performing the operation is provided.

An element in which a pair of connecting pieces are provided at both ends in a state of being shifted by 180 ° in the circumferential direction and the phases of the connecting pieces at both ends are shifted by 90 ° from each other, and a plurality of elements are sequentially connected by the connecting pieces. It comprises a connecting means for rotatably connecting, a guide provided at a position shifted from the connecting piece by approximately 45 ° in a circumferential direction of the element, and a traction member guided by the guide to bend the plurality of elements. The present invention relates to a multi-joint bending mechanism.

According to such a bending mechanism, the connecting piece and the 4
By the traction member guided by the guide provided at a position shifted by 5 °, the bending mechanism including a plurality of elements can be bent in a desired direction. Moreover, the guide and the traction member are prevented from interfering with the connecting means.

According to a configuration in which a connection hole is formed in each of the connection pieces of the element and the connection hole is rotatably connected by a rivet or a pin, a connection mechanism including such a rivet or a pin is provided. The traction member and the guide can be arranged in an offset state.

According to the configuration in which the guide is fixed to the inner peripheral surface of the element, a multi-joint bending mechanism in which a wire cable is routed in the element is provided.

[Brief description of the drawings]

FIG. 1 is a front view showing the entire structure of an endoscope.

FIG. 2 is an enlarged perspective view of a part of an intermediate element.

FIG. 3 is a perspective view of a bending portion.

FIG. 4 is an enlarged vertical sectional view of a bending portion.

FIG. 5 is a plan view showing a moment vector.

FIG. 6 is a plan view of an intermediate element for explaining a bending moment.

FIG. 7 is a plan view of an intermediate element for explaining a bending moment.

FIG. 8 is a perspective view showing a bending portion for measuring a bending moment.

FIG. 9 is a perspective view showing an intermediate element according to another embodiment.

FIG. 10 is an enlarged vertical sectional view of the intermediate element.

FIG. 11 is an enlarged perspective view of a conventional intermediate element.

FIG. 12 is a perspective view of the bending portion.

FIG. 13 is an enlarged cross-sectional view of a conventional bending portion.

[Explanation of symbols]

1 ‥‥ Intermediate element, 2 ‥‥ Connection piece, 3 ‥‥ Rivet, 4 ‥‥ Tip element, 5 ‥‥ Wire guide, 6 ‥
‥ Wire cable, 7 ‥‥ Tube, 8 ‥‥ Dead space, 11 ‥‥ Tip, 12 ‥‥ Bend, 13 ‥‥ Flexible part, 15 ‥‥ Operation part, 16 ‥‥ Universal cord, 1
7 ‥‥ operation knob, 20 ‥‥ intermediate element, 21 、 connection piece (one end), 22 、 connection piece (other end), 23, 24 ‥
{Connection hole, 25} rivet, 30} tip element, 31 ‥‥ root element, 35 ‥‥ wire guide,
36 ‥‥ wire cable, 40 ‥‥ tube, 41 ‥‥
Connection member, 42 ‥‥ dead space

Claims (6)

[Claims] 1. A method of connecting a plurality of elements so as to be alternately rotatable about axes orthogonal to each other and pulling a wire cable inserted through a wire guide provided on an inner peripheral side of the element. A multi-joint bending mechanism, wherein the wire guide is arranged at a position shifted in a circumferential direction with respect to an axis serving as a rotation center of the element. 2. The multi-joint bending mechanism according to claim 1, wherein said wire guide is circumferentially shifted by about 45 ° with respect to an axis serving as a rotation center of said element. 3. The multi-joint bending mechanism according to claim 1, wherein a bending portion of the endoscope is formed by a plurality of elements that are connected to bendable with each other. 4. An element in which a pair of connecting pieces are provided at both ends in a state of being shifted by 180 ° in the circumferential direction, and the phases of the connecting pieces at both ends are shifted by 90 ° from each other; Connecting means for sequentially and rotatably connecting by means of a piece;
A multi-joint bending mechanism comprising: a guide provided at a position shifted by 5 °; and a traction member guided by the guide to bend the plurality of elements. 5. The multi-joint bending mechanism according to claim 4, wherein a connection hole is formed in each of the connection pieces of the element, and the connection hole is rotatably connected to the connection piece by a rivet or a pin. . 6. The multi-joint bending mechanism according to claim 4, wherein said guide is fixed to an inner peripheral surface of said element.