JP2003144382A - Curved tube for endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curved tube for an endoscope, in which the diameter of a pivot part for linking adjacent node rings can be reduced and a sufficient linking strength can be secured. SOLUTION: An outer tongue piece 16a is equipped with a through window 19 for confirming the locating condition of a rod pin 12 from the appearance when an inner tongue piece 16b in the overlapping part of a preceding and following adjacent node ring 11 is overlapped with the outer tongue piece 16a almost in a regular position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending tube for an endoscope, which is disposed at a distal end portion of an insertion portion inserted into a lumen.

[0002]

2. Description of the Related Art Generally, at the tip of the insertion portion of an endoscope,
A bending tube that can bend in any direction is provided. A plurality of node rings are arranged side by side in the front-rear direction on the curved tube, and connecting portions of adjacent front and rear node rings are rotatably connected to each other. The bending tube is connected to a bending operation mechanism on the operation portion side via an operation wire. Then, the bending tube can be bent through the operation wire by remote operation on the operation unit side.

Further, generally, a pair of tongue pieces are projected at both front and rear ends of each node ring of the bending tube along the axial direction of the insertion portion. A fitting hole is formed in each tongue piece. Then, with the tongues of the adjacent front and rear node rings overlapped, insert the rivet type shaft pin from the inside into the insertion hole of the overlapped tongues and mechanically crimp the end of the shaft pin. Thus, the respective node rings are rotatably connected.

While this mechanical caulking portion is necessary to prevent the shaft pin from coming off, in an endoscope for which a smaller diameter is desired in recent years, the caulking portion of the shaft pin is curved, although locally. Since it protrudes outward from the outer peripheral surface of the tube, it causes an increase in the outer diameter of the curved tube, and therefore improvement has been desired.

As an improvement of this, for example, Japanese Utility Model Laid-Open No. 60-187702 and Japanese Patent Laid-Open No. 10-24879.
A curved tube having the configuration shown in Japanese Patent No. 6 has been devised. In Japanese Utility Model Laid-Open No. 60-187702, fitting holes are formed in the tongue pieces that are superposed on each other at the connecting portions of the front and rear node rings that form the bending tube, and the shaft pins are inserted through these fitting holes. . Here, the length of the shaft pin is a length corresponding to the total thickness of the tongue pieces that are overlapped.
Then, when the shaft pin is inserted from the inside into the fitting hole of the tongue pieces that are overlapped with each other, the head end surface of the shaft pin is arranged substantially flush with the outer surface of the outer tongue piece. In this state, by welding the outer peripheral surface of the shaft pin and the inner peripheral surface of the fitting hole of the outer tongue piece with light energy such as laser, each node ring is connected through the shaft pin, and turning performance is obtained. At the same time, there is no occurrence of a protruding caulking portion as in mechanical caulking, and it is possible to reduce the diameter of the bending tube.

Further, Japanese Unexamined Patent Publication No. 10-248796 discloses a curved tube having a structure different from that of Japanese Utility Model Laid-Open No. 60-187702. Here, as shown in FIG. 7 (A), the fitting hole b is formed only in the overlapped inner tongue piece b1 in the connecting portion c between the front and rear node rings a and b forming the bending tube.
2 is formed, and the fitting hole is not formed in the outer tongue piece a1. The shaft pin d is formed in a length such that the head end surface of the shaft pin d substantially contacts the inner surface of the tongue piece a1 at the outer position.
Then, with the shaft pin d inserted from the inside, light energy such as a laser is radiated from the outer surface side of the tongue piece a1 at the outer position to weld the tongue piece a1 at the outer position and the head end surface of the shaft pin d. There is. Even with such a configuration
Since there is no caulking portion protruding outward from the outer peripheral surface of the bending tube as in Japanese Patent No. 2, it is possible to reduce the diameter of the bending tube.

[0007]

By the way, in recent endoscopes, in order to reduce the diameter, the nodal ring used for the bending tube is formed to have a very thin wall thickness. Naturally, the thickness of the tongue is also very thin.

Therefore, in the bending tube disclosed in Japanese Utility Model Laid-Open No. 60-187702, the inner peripheral surface of the fitting hole of the tongue piece at the outer position which is superposed on the connecting portion of the front and rear node rings forming the bending tube. Since it is a welded portion, it is difficult to secure a sufficient welded area, and there is a problem that the weld strength becomes relatively weak. Here, if the thickness of the tongue piece is increased, a large welding area can be secured and the strength is improved, but it is contrary to the reduction of the diameter of the endoscope.

Further, in the bending tube disclosed in Japanese Patent Laid-Open No. 10-248796, the entire head end surface of the shaft pin d can be welded to the inner surface of the tongue piece a1 at the outer position, so that a relatively wide welding area can be secured. It is possible and considered strong in terms of strength. However, in this case, since the outer tongue piece a1 does not have a fitting hole or the like, when the tongue pieces a1 and b1 are superposed on each other, the head of the shaft pin d cannot be seen from the outside of the curved tube. It becomes very difficult to align the spot center with the center of the shaft pin d. That is, although it is originally desired to weld the outer tongue piece a1 to the entire head portion of the shaft pin d, the spot of light energy actually shifts, and only a part of the head portion of the shaft pin d is welded. Poor welding may occur. In this case, the joint strength between the outer tongue piece a1 and the head portion of the shaft pin d is apt to be weaker than the proper strength, so that the mechanical strength of the bending tube may be weakened.

Further, in Japanese Unexamined Patent Publication No. 10-248796, as shown in FIG. 7 (A), the tongue pieces at the outer position where the connecting portions c between the front and rear node rings a and b that form the curved tube are superposed on each other. a1 is formed with a width substantially equal to the diameter of the small diameter portion d1 of the shaft pin d, and the tip projection of the tongue piece a1 is formed on a semicircular arc whose diameter is the width of the tongue piece a1. The configuration is shown in which the tongue pieces a1 are overlapped with each other so that the circumferential portion of the small diameter portion d1 and the semicircular portion of the tip protruding portion a2 of the tongue piece a1 coincide with each other, and light energy is emitted. That is, according to such a configuration, if the light energy is irradiated toward the center of the semicircular tip projection a2 of the tongue piece a1 at the outer position,
Since the spot center naturally comes to the center of the head of the shaft pin d, the outer tongue piece a1 can be welded to the entire head of the shaft pin d.

However, even with such a construction, if light energy of a level capable of welding the entire head of the shaft pin d is applied, the outer tongue piece a1 actually melts out as shown in FIG. 7B. In some cases, it may be difficult to ensure sufficient welding strength after all.

The present invention has been made in view of the above circumstances, and an object thereof is to make it possible to reduce the diameter of a pivotally connecting portion for connecting adjacent node rings and to secure a sufficient connecting strength. It is to provide a bending tube of an endoscope.

[0013]

The invention according to claim 1 is arranged at the distal end portion of an insertion portion to be inserted into a lumen, and
A plurality of node rings are arranged side by side in the front-rear direction, the end surface of the shaft member is welded to the outer connecting portion of the overlapping portion where the connecting portions of adjacent front and rear node rings are overlapped, and the inner side of the overlapping portion In the bending tube of the endoscope in which the plurality of node rings are rotatably connected to each other by inserting the shaft member into the fitting hole formed in the connecting portion, the connection inside the overlapping portion is formed. The outer connecting portion is provided with a through window through which the arrangement state of the shaft member can be confirmed from the appearance when the outer portion and the outer connecting portion are substantially overlapped with each other at a regular position. It is a curved tube of an endoscope. In the invention of claim 1, when the connecting portions of the adjacent front and rear node rings are overlapped with each other, the position of the shaft member is visually confirmed from the outside of the node ring through the through window of the outer connecting portion. To do. After that, light energy such as a laser is applied to the connecting portion at the outer position aiming at the axial center of the shaft member, and the connecting portion at the outer position is welded to the entire head portion of the shaft member.

The invention according to claim 2 is the bending tube for an endoscope according to claim 1, wherein the through window is arranged at a position where the outer peripheral portion of the shaft member can be confirmed. . Further, in the invention of claim 2, the position of the shaft member is visually confirmed from the outside of the nodal ring through the through window at a position where the outer peripheral portion of the shaft member can be confirmed.

According to a third aspect of the present invention, the shaft member has a minute index formed at the center of the end face thereof, and the through window is arranged at a position where the index can be confirmed from the appearance. The bending tube for an endoscope according to claim 1, wherein. Further, in the invention of claim 3, the index of the shaft member is visually confirmed from the outside of the node ring through the through-window at the position where the index of the shaft member can be confirmed.

The invention according to claim 4 is the bending tube for an endoscope according to claim 3, wherein the index is formed in a concave shape. In the invention of claim 4, the concave index of the shaft member is visually confirmed from the outside of the node ring to surely confirm it.

According to a fifth aspect of the present invention, the shaft member has a protrusion portion formed at a central portion of an end surface thereof, and the through window is formed so as to be fitted to the protrusion portion. The curved tube of the endoscope according to claim 1. Further, in the invention of claim 5, while visually confirming the protrusion at the center of the end surface of the shaft member from the outside of the nodal ring through the through window of the outer connecting portion, the protrusion of the shaft member is connected to the outer connecting portion. By fitting it into the through window, the overlapping portion of the connecting portions of the adjacent front and rear node rings is prevented from being displaced.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIGS. 1 (A), 1 (B) to 3. FIG. 1A schematically shows the overall configuration of a flexible endoscope 1 which is an endoscope according to this embodiment. An operation section 3 is connected to the proximal end of an insertion section 2 inserted into the lumen of the flexible endoscope 1. Further, an eyepiece section 4 is arranged at the base end of the operation section 3.

Further, in the insertion section 2, a bending tube 6 is connected to the tip of the elongated flexible tube 5, and a tip end hard portion 7 is connected to the tip of the bending tube 6. Further, the operation section 3 is provided with an angle operation knob 8 for operating the bending tube 6. By rotating the angle operation knob 8, the bending tube 6 can be remotely bent in the vertical direction via an operation wire 15 described later.

Further, FIG. 1B shows the tip portion of the insertion portion 2,
In particular, it shows a schematic configuration near the bending tube 6. Here, in the insertion portion 2, a channel 9 that serves as an insertion passage for water and suction, a treatment tool, etc., an image guide fiber 10 for transmitting an image, a light guide (not shown) for supplying illumination light to the tip. Built-in fiber etc. The tips of these built-in objects are connected to the tip rigid portion 7. The proximal end side of the channel 9 is the channel opening of the operating section 3, the proximal end side of the image guide fiber 10 is the eyepiece section 4, and the proximal end side of the light guide fiber (not shown) is the universal section connected to the operating section 3. It is connected to a connector or the like (not shown) at the tip of the cord.

The bending tube 6 has a plurality of node rings 11 arranged side by side in the front-rear direction of the insertion portion 2 and rotatably connected by rivet type shaft pins (shaft members) 12. The tip side of the bending tube 6 is the tip rigid portion 7, and the base side is the connecting tube 1
It is connected to the flexible tube 5 via 3 and its outer circumference is covered with an outer tube 14.

Further, a plurality of node rings 11 constituting the bending tube 6
At the most tip end of, the tip ends of the operation wires 15 are connected at substantially opposite positions in the vertical direction. The proximal end portion of each operation wire 15 extends through the insertion portion 2 to the operation portion 3 and is connected to a bending operation mechanism (not shown) incorporated in the operation portion 3. Further, an angle operation knob 8 is connected to the bending operation mechanism. Then, by rotating the angle operation knob 8, either one of the two wires 15 connected to the bending operation mechanism in the operation portion is pulled. At this time, each node ring 11 of the bending tube 6 rotates in a fixed direction around the shaft pin 12 as an axis, that is, the bending tube 6 is bent.

FIG. 2 shows the structure of the connecting portion of the plurality of node rings 11 forming the bending tube 6. Here, the node ring 11 is formed of a metal tubular member. A pair of tongue pieces (coupling portions) 16 are provided on the distal end portion and the proximal end portion of the node ring 11.
Each of a and 16b is formed so as to project in the axial direction of the insertion portion 2.

Further, a pair of tongue pieces 16b projecting from the base end side of each node ring 11 are formed with step portions 17 bent inward. Here, 1 on the base end side of each node ring 11
The distance L1 between the outer surfaces of the pair of tongue pieces 16b is equal to the distance L between the inner surfaces of the pair of tongue pieces 16a projecting from the tip side of each node ring 11.
It is formed to be equal to or slightly smaller than 2. Then, in a state where the plurality of node rings 11 are arranged in the axial direction of the insertion portion 2, a tongue piece 16b on the base end side of the adjacent front side node ring 11 and
It is set so that the tongue piece 16a on the front end side of the node ring 11 on the rear side can be overlapped.

The rivet type shaft pin 12 has a large diameter portion 12a and a small diameter portion 12 having a diameter smaller than the large diameter portion 12a.
b are formed. Further, a fitting hole 18 having a diameter slightly larger than the small diameter portion 12b at the tip of the shaft pin 12 is formed in the tongue piece 16b on the proximal end side of each node ring 11. The small diameter portion 12b of the shaft pin 12 can be inserted into the fitting hole 18. The diameter of the large diameter portion 12a of the shaft pin 12 is set to be larger than the diameter of the fitting hole 18 of the tongue piece 16b on the base end side of each node ring 11.

Further, the length of the small diameter portion 12b of the shaft pin 12 is such that the small diameter portion 12b is inserted from the inside of the node ring 11 into the fitting hole 18 of the tongue piece 16b, and the large diameter portion 12a of the shaft pin 12 is inserted into the tongue piece 1.
The length of the head portion 12c of the small diameter portion 12b of the shaft pin 12 is set so as to be substantially in contact with the inner surface of the tongue piece 16a while being substantially in contact with the inner surface of 6b.

The tongue pieces 16a of the adjacent node rings 11 are
16b are overlapped, and the insertion hole 1 of the tongue piece 16b of the node ring 11
2 with the small-diameter portion 12b of the shaft pin 12 inserted in FIG.
As shown in FIG. 5, the tongue piece 16a is irradiated with light energy J such as a laser from the outside of the tongue piece 16a, and the tongue piece 16a is moved to the axial pin 1a.
It is designed to be welded to the second head 12c. By welding the tongue piece 16a of each node ring 11 and the shaft pin 12 in this manner, a plurality of node rings 11 are connected and the pivotal pin 12 serves as a shaft to be rotatable. .

Further, as shown in FIG. 3, the tongue piece 16a is formed such that its width is slightly larger than the diameter of the small diameter portion 12b of the shaft pin 12. Furthermore, the tip end protruding portion 16a1 of the tongue piece 16a is formed in a semicircular shape having a diameter as its width. Then, the small diameter portion 12b of the shaft pin 12 is attached to the tongue piece 16
When each node ring 11 is connected in such a manner that the center O1 of the small diameter portion 12b of the shaft pin 12 and the center O2 of the semicircular tip protruding portion 16a1 are inserted into the insertion hole 18 of b and are substantially aligned with each other. It is configured to have a curved angle of.

Further, the tongue piece 16a is formed with a plurality of through windows 19, in the present embodiment, three through windows 19. These through windows 19 are formed in the small diameter portion 12 of the shaft pin 12 on the tongue piece 16a.
They are arranged at substantially equal intervals along the outer peripheral surface of the shaft pin 12 at the joining position of b. Then, the tongue piece 16a and the tongue piece 16b are superposed so that the center O1 of the small diameter portion 12b of the shaft pin 12 and the center O2 of the semicircular tip protruding portion 16a1 substantially coincide with each other, and these tongue pieces 16a and 16b are passed through these through windows 19. The outer peripheral portion of the small diameter portion 12b of the shaft pin 12 can be visually observed from the outer appearance of the bending tube 6 at several points.

The shape of the through window 19 is not particularly limited, but the through window 19 is intended to determine the central position of the small diameter portion 12b of the shaft pin 12 by recognizing a part of the outer peripheral portion of the shaft pin 12. It is desirable that the outer peripheral portion of the small diameter portion 12b of the shaft pin 12 can be confirmed at about three places for that purpose. Further, from the viewpoint of the strength of the tongue piece 16a, it is desirable that the occupied area of the through window 19 be as small as possible at a level where the outer peripheral portion of the small diameter portion 12b of the shaft pin 12 can be recognized. For example, FIG. 3 shows an example in which the through window 19 is formed by three slits extending along the radiation with reference to the center O2 of the semicircular tip protrusion 16a1 of the tongue piece 16a. They are arranged with the same shape and the same distance with respect to the center O2. Further, the width X of the slit of the through window 19 is formed as small as possible within a range in which the outer peripheral portion of the shaft pin 12 can be recognized from the outside of the bending tube 6. The length Y of the slit is 1 tongue piece.
6a and the tongue piece 16b are overlapped with each other, the center O1 of the small diameter portion 12b of the shaft pin 12 and the semi-circular tip protruding portion 16a1
Even if the center O2 of the shaft is slightly deviated, the outer peripheral portion of the small diameter portion 12b of the shaft pin 12 can be observed at several points.
It is formed slightly longer than the width X.

Next, the operation of the above configuration will be described.
At the time of assembling work for assembling the bending tube 6 of the flexible endoscope 1 of the present embodiment, a plurality of node rings 11 are arranged in the axial direction of the insertion portion 2, and a tongue piece 16 on the base end side of the adjacent front node ring 11 is arranged.
b and the tongue piece 16a on the tip side of the node ring 11 on the rear side are overlapped. At this time, the tongue pieces 1 of the adjacent front and rear node rings 11
6a and 16b are roughly overlapped. Then, the small diameter portion 12b of the shaft pin 12 is inserted from the inside of the node ring 11 into the fitting hole 18 of the tongue piece 16b by an appropriate jig, and the head portion 12c of the small diameter portion 12b of the shaft pin 12 is inserted as shown in FIG. Tongue 16a
To substantially contact the inner surface of the.

Thereafter, as shown in FIG. 3, from the through window 19 of the tongue piece 16a of each node ring 11 to the small diameter portion 12b of the shaft pin 12.
The tongue pieces 16a, 16b of the node ring 11 so that the outer periphery of the
Adjust the stacking of.

Further, after fine adjustment is made so that the areas of the small diameter portion 12b of the shaft pin 12 observed from the respective through windows 19 become substantially equal, the semicircular tip projection 16a of the tongue piece 16a.
The tongue piece 16a is irradiated with light energy J such as a laser around the center O2 of 1 to weld the tongue piece 16a to the entire head 12c of the small diameter portion 12b of the shaft pin 12.

Therefore, the following effects can be obtained with the above configuration. That is, in the present embodiment, since the three through windows 19 are formed in the tongue piece 16a of the node ring 11, the head 12c of the shaft pin 12 is visually confirmed through the through window 19 to check the outside of the tongue piece 16a. It is possible to confirm the arrangement of the shaft pin 12 below the tongue piece 16a, and the tongue piece 16a can be arranged at an appropriate position with respect to the shaft pin 12. Therefore, since the center of the small diameter portion 12b of the shaft pin 12 can be accurately determined, the spot center of the light energy J of the laser or the like can be accurately aligned with the axis of the small diameter portion 12b of the shaft pin 12, The tongue piece 16a can be welded uniformly over the entire head portion 12c of the shaft pin 12. Therefore, there is an effect that the connection strength of each node ring 11 that is always high and stable can be secured.

It should be noted that the through window 19 is not limited to a slit, for example, but may be formed of a through hole having a width X substantially equal to the diameter, but there is no particular problem.
To form the center O1 of the small diameter portion 12b of the shaft pin 12,
Even if the center O2 of the semicircular tip protrusion 16a1 is slightly displaced, the outer peripheral portion of the small-diameter portion 12b of the shaft pin 12 cannot be confirmed, and thus it takes some time to overlap with the tongues 16a and 16b. there is a possibility. Therefore, if the through window 19 is formed in the slit shape as described above, the outer peripheral portion of the small diameter portion 12b of the shaft pin 12 can be easily confirmed when the tongue piece 16a and the tongue piece 16b are overlapped, The small diameter portion 1 of the shaft pin 12 visible from the slit of each through window 19
If the areas 25 of 2b are finely adjusted to be substantially equal to each other, the center O1 and the center O2 can be made to substantially coincide with each other, so that the work of superposing the tongue pieces 16a and 16b becomes easy.

The through window 19 may be formed as a hole whose slit length Y is approximately the diameter. However, in this case, the area occupied by the through window 19 is widened and the strength of the tongue piece 16a is somewhat increased. It may decrease. Therefore, it is desirable that the through window 19 be formed in a slit shape as shown in FIG. However, when the mechanical strength required for the curved tube 6 is satisfied, there is no problem even if it is formed with a slightly larger hole as described above, and in consideration of the workability of the through window 19, the through window 1
Instead of providing a plurality of 9, a single through window 20 having a substantially Y-shape in which the through windows 19 are connected may be configured as in the modification shown in FIG.

Further, FIGS. 5A and 5B show the second embodiment of the present invention.
FIG. In this embodiment, the configuration of the bending tube 6 of the first embodiment (see FIGS. 1A and 1B to 3) is modified as follows.

That is, in the present embodiment, as shown in FIG. 5B, an index 21 formed of a minute recess is provided at the center of the head 12c of the shaft pin 12. Further, a pair of tongue pieces 16a projecting from the tip end side of each node ring 11 is provided with a through hole 22 having a minute circular hole at the center O2 of the semi-circular tip protrusion portion 16a1. This through window 22 is an index 21
It is formed slightly larger than. And the shaft pin 1
With the small-diameter portion 12b of No. 2 inserted into the fitting hole 18 of the tongue piece 16b, as shown in FIG.
By overlapping 6b, the small diameter portion 12b of the shaft pin 12
Center O1 of the tip is formed as a center O2 of a semi-circular protrusion
It is possible to adjust to.

Next, the operation of this embodiment having the above configuration will be described. At the time of assembling work for assembling the bending tube 6 of the flexible endoscope 1 of the present embodiment, the plurality of node rings 11 are inserted into the insertion portion 2
The tongue pieces 16b on the base end side of the adjacent front side node ring 11 and the tongue pieces 16a on the tip side of the rear side node ring 11 are overlapped with each other in the state of being aligned in the axial direction. At this time, as shown in FIG. 5 (A), the tongue piece 16 is arranged so that the entire index 21 of the head 12c of the shaft pin 12 can be confirmed from the through window 22 of the tongue piece 16a.
Adjust the superposition of a and 16b.

Thereafter, the tongue piece 16 is centered on the through window 22.
The hole energy J of a laser or the like is radiated to a tongue piece 16a.
Is welded to the entire head portion 12c of the small diameter portion 12b of the shaft pin 12.

Therefore, in this embodiment, since the through window 22 is formed in the tongue piece 16a of the node ring 11, the tongue piece 16a of the shaft pin 12 is visually confirmed from the through window 22 to visually confirm the tongue. The arrangement of the shaft pin 12 under the tongue piece 16a can be confirmed from the outside of the piece 16a. Therefore, by adjusting the superposition of the tongues 16a and 16b so that the entire index 21 of the head 12c of the shaft pin 12 can be confirmed from the through window 22, the shaft is placed at an appropriate position with respect to the tongue 16a. Since the pin 12 can be arranged, the spot center of the light energy J of the laser or the like can be accurately aligned with the axis of the small diameter portion 12b of the shaft pin 12 as in the first embodiment, and the tongue piece 16a is provided. The shaft pin 12
The head 12c can be welded entirely and uniformly. Therefore, there is an effect that the connection strength of each node ring 11 that is always high and stable can be secured.

FIG. 6 shows a third embodiment of the present invention. In this embodiment, the configuration of the bending tube 6 of the first embodiment (see FIGS. 1A and 1B to 3) is further modified as follows.

That is, in this embodiment, the protrusion 31 is provided at the center of the head portion 12c of the shaft pin 12. Further, the pair of tongue pieces 16a of each node ring 11 is formed with a through hole 32 having a minute circular hole at the center O2 of the semi-circular tip protruding portion 16a1. Here, the protrusion length of the protrusion 31 of the shaft pin 12 is set to be substantially equal to the thickness of the tongue piece 16a. The protrusion 31 of the shaft pin 12 is formed so that it can be fitted into the through window 32.

Next, the operation of this embodiment having the above configuration will be described. At the time of assembling work for assembling the bending tube 6 of the flexible endoscope 1 of the present embodiment, the plurality of node rings 11 are inserted into the insertion portion 2
The tongue pieces 16b on the base end side of the adjacent front side node ring 11 and the tongue pieces 16a on the tip side of the rear side node ring 11 are overlapped with each other in the state of being aligned in the axial direction. At this time, as shown in FIG. 6, the tongue pieces 16a and 16b are overlapped so that the through window 32 is arranged on the axis of the fitting hole 18 of the tongue piece 16b. Subsequently, the small diameter portion 12b of the shaft pin 12 is inserted from the inside of the node ring 11 into the fitting hole 18 formed in the tongue piece 16b by a proper jig, and the projection 31 protruding from the head portion 12c of the shaft pin 12 is inserted. The tongue piece 16a is fitted into the through window 32.

Thereafter, the tongue piece 16a is irradiated with light energy J such as a laser around the projection 31 of the shaft pin 12 to weld the projection 31 to the inner peripheral portion of the through window 32, and the tongue piece 16a is fixed to the shaft pin 12. Head 12 of 12 small diameter portion 12b
c Weld all over.

Therefore, in this embodiment, since the through window 32 is formed in the tongue piece 16a of the node ring 11, the tongue piece 16a of the shaft pin 12 is visually confirmed from the through window 32 to visually confirm the tongue. The arrangement of the shaft pin 12 under the tongue piece 16a can be confirmed from the outside of the piece 16a. Therefore, by adjusting the superposition of the tongues 16a and 16b so that the entire projection 31 of the head 12c of the shaft pin 12 can be confirmed from the through window 32, the shaft is positioned at an appropriate position with respect to the tongue 16a. Since the pin 12 can be arranged, the spot center of the light energy J of the laser or the like can be accurately aligned with the axis of the small diameter portion 12b of the shaft pin 12 as in the first embodiment, and the tongue piece 16a is provided. The shaft pin 12
The head 12c can be welded entirely and uniformly. Therefore, there is an effect that the connection strength of each node ring 11 that is always high and stable can be secured.

Further, in the present embodiment, since the projection 31 of the shaft pin 12 is fitted into the through window 32 of the tongue piece 16a, the tongue pieces 16a and 16b are not misaligned after the shaft pin 12 is inserted. .

Furthermore, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention. Next, other characteristic technical matters of the present application will be additionally described as follows. Note (Additional Item 1) The connecting portions of adjacent node rings are overlapped with each other, and the shaft member is inserted into the fitting hole formed in the first connecting portion located on the inner side of the overlapping connecting portions.
In a bending tube of an endoscope in which a plurality of node rings are rotatably connected to each other by welding a second connecting portion located outside and an end surface of the shaft member to the first connecting portion. A through window is formed in the second connecting portion so that the arrangement state of the shaft member can be visually confirmed when the second connecting portion is substantially overlapped with the regular position. Curved tube of endoscope.

(Additional Item 2) The bending tube for an endoscope according to claim 1, wherein the through window is formed so that the outer peripheral portion of the shaft member can be confirmed at at least one place.

(Additional Item 3) A minute index is formed at the center of the end surface of the shaft member, and the through window is formed so that the index can be confirmed from the appearance. The bending tube of the endoscope according to 1.

(Additional Item 4) The bending tube for an endoscope according to claim 3, wherein the index is formed in a concave shape.

(Additional Item 5) A protrusion is formed at a central portion of an end surface of the shaft member, and the through window is formed so as to be fitted to the protrusion. Endoscopic curved tube.

(Prior Art of Supplementary Items 1 to 5) A bending tube is usually formed at the distal end of the insertion portion of the endoscope, and the bending tube can be bent via an operation wire by remote operation on the operation section side. Is possible. Generally, a curved tube is formed by connecting a plurality of node rings each having a pair of tongue pieces protruding in the longitudinal direction from the end. Fitting holes are formed in each tongue piece, and with the tongue pieces of adjacent node rings stacked,
A rivet type shaft pin is inserted from the inside into the fitting holes of the tongues that are overlapped, and the end portions of the shaft pin are mechanically caulked to connect the respective node rings and ensure rotatability. But,
While this mechanical caulking part is necessary to prevent the shaft pin from coming off, in an endoscope that is recently required to have a reduced diameter, it locally increases the outer diameter of the bending tube. Since it becomes a cause, improvement was desired. In order to improve these, the full-scale utility model Sho 60-187702 and Japanese Unexamined Patent Publication No.
As shown in 248796, there has been devised a curved tube that secures rotatability by welding a rivet type shaft pin to the outer tongue piece by light energy of a laser or the like to connect each node ring.

Fitting holes are formed in the tongue pieces which are superposed on each other, and the shaft pins are inserted into these fitting holes. The length of the shaft pin is equivalent to the total thickness of the tongues that are overlapped, and when the shaft pin is inserted from the inside, the head end face of the shaft pin is the outer surface of the tongue located outside. And is arranged on substantially the same plane. In this state, since the outer peripheral surface of the shaft pin and the inner peripheral surface of the fitting hole of the tongue located on the outer side are welded by the optical energy of the laser or the like, each node ring is connected through the shaft pin to rotate. In addition, the curved tube can be made thinner without the occurrence of a protruding caulking portion unlike mechanical caulking.

On the other hand, in Japanese Unexamined Patent Publication No. 10-248796, the fitting hole is formed only in the tongue located inside, and the fitting hole is not formed in the outside tongue. The shaft pin is formed to have a length such that the head end surface of the shaft pin is substantially in contact with the inner surface of the tongue located on the outer side, and from the outer surface side of the tongue located on the outer side with the shaft pin inserted from the inside. By irradiating light energy from a laser or the like, the tongue located outside and the head end surface of the shaft pin are welded. Even in such a case, since the protruding caulking portion does not occur, the diameter of the bending tube can be reduced.

(Problems to be Solved by Additional Items 1 to 5)
In recent years, in order to reduce the diameter of the endoscope, the nodal ring used for the bending tube is formed to have an extremely thin wall thickness.
Naturally, the thickness of the tongue is also very thin. However, since the curved tube shown in Japanese Utility Model Laid-Open No. 60-187702 uses the inner peripheral surface of the fitting hole of the tongue located on the outer side as the welding portion, it is difficult to secure a sufficient welding area and the welding strength is relatively high. There is a problem that it becomes weak. If the wall thickness of the tongue piece is increased, a large welding area can be secured and the strength is improved, but this is contrary to the reduction in the diameter of the endoscope.

On the other hand, since the curved tube disclosed in Japanese Patent Laid-Open No. 10-248796 can weld the head end surface of the shaft pin, it can be considered that a relatively wide welding area can be secured and the strength is strong. However, since there is no insertion hole in the outer tongue, the head of the shaft pin cannot be seen from the outside when the tongues are overlapped, and it is very easy to align the light energy spot center with the center of the shaft pin. It will be difficult. In other words, although we originally wanted to weld the outer tongue to the entire head of the shaft pin, the spot of light energy actually shifted, and only a part of the head of the shaft pin could be welded. Something, that is, something weak in strength may occur. On the other hand, as shown in FIG. 3, the tongue located on the outside is formed with a width substantially equal to the diameter of the small diameter portion of the shaft pin, and the tip projection of the tongue is a semicircular arc whose diameter is the width of the tongue. Japanese Patent Application Laid-Open No. 10- 248796. That is, according to such a configuration,
If the light energy is irradiated aiming at the center of the semicircular part of the tongue located on the outer side, the spot center will naturally come to the center of the head of the shaft pin, so the outer tongue will be the entire head of the shaft pin. It is possible to weld to. However, even with such a configuration, if light energy of a level capable of welding the entire head of the shaft pin is applied, the outer tongue may actually melt out as shown in FIG. It may be difficult to secure a sufficient welding strength.

(Purposes of Additional Items 1 to 5) An object of the present invention is to provide a bending tube capable of reducing the diameter of a pivotally connecting portion connecting adjacent node rings and ensuring sufficient connection strength. To do.

(Operation of Supplementary Note 1) The tongue pieces of adjacent node rings are overlapped with each other, and the position of the shaft pin is confirmed from the external appearance through the through window formed in the tongue piece located outside. afterwards,
The tongue located on the outer side of the shaft pin is irradiated with light energy such as a laser aiming at the center of the shaft, and the tongue located on the outer side is welded to the entire head of the shaft pin.

(Effects of Supplementary Items 1 to 5) Since the through window is formed in the tongue piece located on the outer side, the arrangement of the shaft pin can be confirmed from the external appearance through the through window. Therefore, since it is possible to irradiate the optical energy of the laser or the like by accurately aiming the center of the axis of the axis pin,
It is possible to evenly weld the entire head portion of the shaft pin, and it is possible to secure sufficient and stable connection strength.

[0061]

According to the first aspect of the present invention, when the inner connecting portion and the outer connecting portion of the overlapping portion are substantially overlapped with each other at the regular position, the arrangement of the shaft members can be visually confirmed. Since a possible through window is provided in the outer connecting portion, the disposition of the shaft member can be confirmed from the appearance through the through window of the connecting portion at the outer position of the overlapping portion. Therefore, since it is possible to precisely aim at the shaft center of the shaft member and irradiate light energy such as a laser, the connecting portion at the outer position is provided on the entire head part of the shaft member.
In addition, it is possible to weld them uniformly, and it is possible to reduce the diameter of the pivotally connecting portion that connects adjacent node rings, and it is possible to secure sufficient connection strength.

According to the second aspect of the present invention, the position of the shaft member can be visually confirmed from the outside of the node ring through the through window at a position where the outer peripheral portion of the shaft member can be confirmed.

According to the third aspect of the invention, the index of the shaft member can be visually confirmed from the outside of the node ring through the through window at the position where the index of the shaft member can be confirmed.

According to the fourth aspect of the present invention, the concave index of the shaft member can be visually confirmed from the outside of the node ring without fail.

According to the fifth aspect of the present invention, the protrusion at the center of the end face of the shaft member can be visually confirmed from the outside of the node ring through the through window of the outer connecting portion, and the protrusion of the shaft member can be confirmed. By fitting the to the through window of the outer connecting portion, the overlapping portion of the connecting portions of the adjacent front and rear node rings is not displaced.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention,
(A) is a side view showing a schematic configuration of the entire endoscope, and (B) is a longitudinal sectional view showing an internal configuration of a bending tube.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a plan view of a main part showing a through window of a bending tube of the endoscope according to the first embodiment.

FIG. 4 is a plan view of a main part showing a modified example of the through window of the bending tube of the endoscope according to the first embodiment.

FIG. 5 shows a second embodiment of the present invention,
(A) is a plan view showing the main configuration of the bending tube of the endoscope,
(B) is a VB-VB line sectional view of (A).

FIG. 6 is a vertical cross-sectional view of a main part showing a third embodiment of the present invention.

FIG. 7 is a perspective view of a main part of a conventional endoscope, showing a structure of a main part of a bending tube, wherein (A) is a perspective view of a main part showing a connecting portion between front and rear node rings forming the bending tube; FIG. 7 is a perspective view of a main part showing a state in which an outer tongue piece is melted out when the entire head portion of the shaft pin is laser-welded to a connecting portion between the node rings.

[Explanation of symbols]

2 Insert 11 joint rings 16a, 16b Tongue piece (connecting portion) 12 Shaft pin (Shaft member) 19 Through window

Claims (5)

[Claims] 1. A plurality of node rings are arranged side by side in the front-rear direction while being arranged at the distal end of an insertion part to be inserted into a lumen, and connecting parts of adjacent front and rear node rings are overlapped with each other. By welding the end surface of the shaft member to the outer connecting portion of the overlapping portion and inserting the shaft member into the fitting hole formed in the inner connecting portion of the overlapping portion, the plurality of node rings are respectively formed. In a bending tube for an endoscope that is rotatably connected, when the inner connecting portion and the outer connecting portion of the overlapping portion are substantially overlapped with each other at a regular position, from the appearance, A bending tube for an endoscope, wherein a through window through which the arrangement state can be confirmed is provided in the outer connecting portion. 2. The bending tube for an endoscope according to claim 1, wherein the through window is arranged at a position where the outer peripheral portion of the shaft member can be confirmed. 3. The shaft member has a minute index formed at the center of the end face thereof, and the through window is arranged at a position where the index can be confirmed from the appearance. The bending tube for an endoscope according to claim 1. 4. The bending tube for an endoscope according to claim 3, wherein the index is formed in a concave shape. 5. The shaft member according to claim 1, wherein a protrusion is formed at a center portion of an end surface of the shaft member, and the through window is formed so as to be fitted to the protrusion. Curved tube of the described endoscope.