Apparatus for adjusting the flexing of the bending section of an endoscope

Abstract

An apparatus for adjusting the flexing of the bending section of an endoscope extending between the distal end and flexible tube, which comprises a pair of wire members partly wound about a pulley in opposite directions on the opposite sides of said pulley in a state fixed to the pulley at one end and connected to the bending section at the other end such that the one way rotation of the pulley causes one of the wire members to be stretched and the other to be loosened; and a wire sagging-preventing device disposed intermediate each of said wire members so as to eliminate the excessive sagging of the wire members.

Description

BACKGROUND OF THE INVENTION

This invention relates to an endoscope and more particularly to an endoscope wherein the bending section extending between the flexible tube and distal end can have the degree of its flexing properly controlled.

An endoscope used for the observation, examination and medical treatment of organs received in the abdominal cavity such as the stomach and small intestines generally has a bending section extending between the flexible tube and distal end. External control of the degree with which the bending section is flexed enables the distal end to be rotated to a desired position and condition.

The bending section performing the above-mentioned action has a large number of rocking members arranged parallel in a synthetic resin tube along its length, the upper and lower central portions of the respective adjacent ones of a series of said rocking members being connected together by a pin to be rendered swingable in substantially the same plane. The foremost one of said series of rocking members has both right and left sides firmly fitted with the ends of two flexible wire members. The intermediate portions of said wire members are loosely inserted through the right and left sides of all the other rocking members. The wire members pass through the flexible tube to be connected to a control unit fitted to the rear end of said tube. When the control unit is so operated as to stretch one of the wire members and loosen the other, then the bending section of the endoscope can be flexed toward the stretched wire member.

To date, various devices have been designed for the tension and relaxation of the above-mentioned type of wires. However, no fully satisfactory mechanism has been provided. Namely, any process hitherto proposed has failed to meet the requirements that since the endoscope is preferred to be of small size and simple construction from the standpoint of operation, the wire-operating system should similarly have a compact and simple arrangement, and that to attain smooth working, while one of the wires is stretched, the other should be prevented from unduly sagging.

One of the known contrivances using a pinion and a pair of racks wherein two wires are inserted at one end into the penetrating holes of the racks and both racks are made to move in opposite ways by the rotation of the pinion causes one of the wires to be sufficiently loosened through the penetrating holes of the corresponding rack to provide for the flexing of the bending section of an endoscope, and indeed offers the advantage of preventing the loosened wire from presenting excessive sagging. But the above-mentioned contrivance consisting of a pinion and racks has the drawbacks that the whole construction is not only complicated and bulky but also it is necessary to use parts requiring time-consuming mechanical working such as the pinion and rack, eventually resulting in high cost.

According to another device proposed to eliminate the shortcomings of the aforesaid pinion-rack mechanism, two wires are partly wound about a pulley in a state fixed at one end to the pulley and connected to the bending section of an endoscope at the other end. This prior art device effects the flexing of the bending section of an endoscope by rotating the pulley one way further to wind or stretch one of the wires and rewind or loosen the other. Though of simple construction, said device fails to absorb the undesirable sagging of the loosened wire. As the result, the loosened wire presenting such sagging is likely to be displaced from the pulley or have some portions entwined or twisted together, eventually causing its breakage.

SUMMARY OF THE INVENTION

It is accordingly the object of this invention to provide a compact apparatus of simple construction for controlling the flexing of the bending section of an endoscope, and preventing the loosened wire from unduly sagging.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an endoscope;

FIG. 2 is a front view of the endoscope of FIG. 1 with the bending section exploded;

FIGS. 3 and 4 are cross and longitudinal sectional views of an endoscope according to this invention;

FIG. 5 is a cross sectional view on line 5--5 of FIG. 3;

FIG. 6 is an oblique view of a modification of the pulley used in the endoscope of this invention; and

FIG. 7 is an oblique sectional view of the wire sagging-preventing device used in the endoscope of the invention.

DETAILED DESCRIPTION OF THE INVENTION

There will now be described by reference to the appended drawings the apparatus of this invention for adjusting the flexing of the bending section of an endoscope.

An endoscope 10 generally comprises, as shown in FIG. 1, a distal end 11 provided with an observation window, illunimation window and forceps opening; a flexible tube 12 for inserting the distal end 11 into the abdominal cavity; and a bending section 13 for deflecting the distal end 11 through a prescribed angle relative to the flexible tube 12. The rear end of the flexible tube 12 is fitted with a control unit 14 for carrying out the various operations of the endoscope from outside of the living body.

The bending section 13 has a large number of annular rocking members 16 arranged in series, as shown in FIG. 2, in a synthetic resin envelope 15 along its length. The annular members 16 have a projection 16a formed on one side substantially at the center. The projecting central portion 16a of each rocking member 16 is pivotally connected to that of the adjacent one by a pin 17. As a result, a series of rocking members 16 is made swingable to the right and left. Both crosswise sides of the rocking members 16 are loosely penetrated by a pair of wire members 17a and 17b, whose forward end is fixed to the foremost one of the series of rocking members 16, namely, the annular member near the distal end of the endoscope. The wire members 17a and 17b pass through wire channels 18a and 18b formed inside of the flexible tube 12, and reach the control unit 14 at the rear end. Where, therefore, the control unit 14 is so operated as to stretch one of the wire members 17 and loosen the other, then the bending section 13 of an endoscope is flexed toward the stretched wire member to an extent corresponding to the degree of said stretching.

The control unit 14 contains a device 19 for controlling the flexing of the bending section 13 of an endoscope by stretching or loosening both wire members 17a and 17b. The wire-operating device 19 has a housing 20 for holding various mechanisms. Rotatably received in the housing 20 is a pulley 21 having a groove 21a cut out in the peripheral surface. The pulley 21 has a rotatable shaft 22 projecting along the rotation axis of said pulley 21. The shaft 22 extends to the outside through the upper side of the housing 20. The exposed end is fitted with a dial 23, whose operation causes the pulley 21 to rotate.

The housing 20 contains that portion of the wire members 17a and 17b which extend through the wire channels 18a and 18b of the flexible tube 12 to the pulley 21 and guide channels 24a and 24b permitting the passage of the wire members 17a and 17b, thereby guiding the later-described wire sagging-preventing device. Said guide channels 24a and 24b are defined by an elongate projection 25 formed at the center of the cavity of the housing 20 so as to extend from the pulley 21 to the flexible tube 12 and guide plates 26a and 26b extending along both sides of the projection 25 at a presecribed interval. The wire members 17a and 17b passing through both sides of the rocking members 16 are partly wound about the pulley 21 in opposite directions on the opposite sides thereof. As previously described, the wire members 17a and 17b are fixed at one end to the pulley 21 and at the other end to the bending section of an endoscope. When, therefore, the pulley 21 is rotated either way, one of the wire members is stretched and the other is loosened to give rise to the flexing of the bending section of the endoscope. The pulley 21 may be partly cut out in fixing the wire members 17a and 17b thereto through said cutout portion 21b.

Wire sagging-preventing devices 27a and 27b are connected, as shown in FIG. 7, to the intermediate portions of the wire members 17a and 17b to eliminate the undue sagging of the wire members. Said devices 27a and 27b each have a cylindrical member 28 open at one end which can slide through the guide channels 24a, 24b. The cylindrical member 28 contains a pair of slidable members 29 sliding therethrough along the length. Screwed into the opening of the cylindrical member 28 is a plugging member 30 provided with screw threads on the peripheral surface. An adjustment member 31 may, as occasion demands, be placed between the plugging member 30 and one of the slidable members 29. Where, therefore, the wires are too much lengthened due to the long use of an endoscope and in consequence fail to attain the desired flexing of a bending section, it is advised to control the extent to which the plugging member 30 is screwed into the opening of the cylindrical member 28 and/or insert the adjustment member 31 between the plugging member 30 and one of the slidable members 29 to restrict the moving rang of the slidable members 29. Then the above-mentioned difficulties will be resolved. The cut portions of each wire member are fixed to the paired slidable members 29 by being conducted through a penetrating hole bored in the closed wall of the cylindrical member 28 and another penetrating hole bored in the plugging member respectively, both holes extending along the central axis of the cylindrical member 28.

There will now be described by reference to FIG. 3 the operation of the wire sagging-preventing devices 27a and 27b. When the dial 23 (FIG. 4) mounted on the top of the projecting end of the rotary shaft 22 is turned in the direction of the indicated arrow in FIG. 3, one wire member 17b is wound about the pulley 21, whereas the other wire member 17a is rewound or loosened. At this time, the wire sagging-preventing device 27b contacting the stretched wire 17b has the slidable members 29 pressed against the inner walls of the cylindrical member 28 on both sides. In the wire sagging-preventing device 27a contacting the rewound or loosened wire member 17a, said loosening causes the slidable member 29 contacting said loosened wire member 17a to travel toward the other slidable member 29, namely, toward the plugging member 30, thereby eliminating the resultant sagging. Accordingly, that portion of the loosened wire member 17a which extends between said other slidable member 29 and the one of the annular members 16 which is closest to said slidable member 29 is saved from undesirable sagging. As the result, the loosened wire member 17a itself is not thrown off the guide channel 24a or wire channel 18a, nor damaged by being pressed against the inner wall of either or both of these channels 24a and 18a.

The wire sagging-preventing device used in the foregoing embodiment does not always have to be formed of one cylindrical member and two slidable members. For example, it is possible to provide one cylindrical member and one slidable member and attach the cut portions of each wire member to these members.

In the apparatus of this invention constructed as described above to adjust the flexing of the bending section of an endoscope, a pulley is of simple construction and a wire sagging-preventing device contacting a wire member is also of simple construction, and yet these members cooperate unfailingly to eliminate the undue sagging of the wire member, thus providing a fully reliable, practically convenient endoscope having an uncomplicated arrangmenet as a whole.

Claims

What is claimed is:

1. An endoscope comprising:

a distal end;

a bending section;

a flexible tube connected to the distal end through the bending section;

said bending section being flexible to deflect the distal end relative to the flexible tube;

a control unit for operating the distal end, said control unit having guide channels therein; and

apparatus for adjusting the flexing of the bending section comprising:

a pulley rotatably received in the control unit;

a pair of operating wires at least partly wound about the pulley in opposite directions on the opposite sides of said pulley, said operating wires being fixed to said pulley at one end and connected to the bending section at the other end thereof, and said operating wires being cut off at an intermediate part thereof; and

a pair of wire sagging-preventing devices slidably received in said guide channels of said control unit, and each including a pair of slidable members respectively coupled between the cut ends of said cut operating wires whereby when one wire sagging-preventing device is drawn toward the pulley via the wire by rotating the pulley in one direction, one of the slidable members of the other wire sagging-preventing device is moved away from the pulley, independently of said other wire sagging-preventing device, to prevent the loosening of the wire connected to said other wire sagging-preventing device.

2. An endoscope according to claim 1 wherein said wire sagging-preventing device includes a cylindrical member in which said paired slidable members are received.

3. An endoscope according to claim 2 wherein said paired slidable members are freely movable relative to each other within said cylinder to take up said sag.

4. An endoscope according to claim 2 wherein said cylindrical member includes means for controlling the moving range of said slidable members received therein.

5. An endoscope according to claim 4 wherein said control means comprises a plugging member screwed into one end of said cylindrical member.

6. An endoscope according to claim 4 wherein said control means comprises an insert located between one of said slidable members and the end wall of the cylindrical member so as to restrict the movement of said slidable members.

7. An endoscope according to claim 1 wherein said paired slidable members are fixedly connected to respectively cut ends of said cut operating wires.

8. An endoscope according to claim 1 wherein said paired slidable members are freely movable relative to each other to take up said sag.