JPH01223925A - Endoscope - Google Patents

Abstract

PURPOSE:To provide an endoscope capable of being easily and smoothly bent from the leading end of a curved part thereof, by a method wherein the thickness of the first elastic film surrounding the outside of each of the nodal rings of the curved part of the endoscope is made small toward the leading end of the curved part. CONSTITUTION:A large number of nodal rings are connected in a curved part in the center axis direction thereof and four wires 2 for bending the curved part are respectively fixed to the inside of the nodal ring positioned at the leading end of the curved part at one ends thereof. Cables 6 such as wiring having a lens or opening part at the leading end part 5 thereof, an illumination fiber, a water feed pipe or the like are passed through the central part of the curved part. A large number of the connected nodal rings 1 are arranged outside the cables 6 and the wires 2 connected to the leading end nodal ring at one ends thereof are passed between the nodal rings 1 and the cables 6. A layer 3 consisting of a flex and a blade is provided outside the nodal rings 1 and the outside of the layer 3 is covered with an elastic film 4a. The elastic film 4a is composed of rubber whose modulus of elasticity is, for example, 60 as rubber hardness and taper is provided thereto so that the thickness of the most leading end part is, for example, 0.1mm and the thickness of the part separated by 50mm from the leading end is, for example, 0.4mm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a medical or industrial endoscope, and particularly to the structure of a curved portion near the tip.

(Prior Art) Endoscopes have conventionally been used to observe internal conditions from parts with small hole diameters, such as in body cavities of living bodies and water pipes. When observing with an endoscope, it is necessary to bend the endoscope over a wide range of angles starting from a portion near the tip so that observations can be made from all angles in a narrow space. For this reason,
For example, the portion of the tip of the endoscope, which is approximately 50 mm in length, is called a curved portion and has a structure that allows it to bend over a large angular range.

FIG. 5 is a schematic diagram showing an example of the structure of the curved portion of the endoscope. Two fulcrums 10a and 10b are provided at the front and rear ends of the ring-shaped node ring 1, respectively. The node ring 1 is rotatable about the supporting points 10a and 10b.
Multiple lines are connected in the direction of the central axis. Fulcrums 10a and 10b
are installed at positions rotated by 90'' from each other, so the curved portion consisting of a plurality of nodal rings 1 can bend in four directions, ASB, C, and D. At the rear end of the nodal ring 1 at the tip, Four wires 2as 2 at each of the four contacts 11
bs 2cs 2d are connected and their wires pass inside the nodal ring. By pulling this wire in the direction of arrow E, the curved portion can be bent. For example, when the wire 2a is pulled in the direction of arrow E, the curved portion bends in the direction of A. Details of this operation will be described later. Although not shown for the sake of simplicity, the distal end portion 5 of the curved portion is provided with an objective lens, a solid-state image sensor, etc., and captures images of the inside of the body cavity. Image information captured from the tip 5 is sent to the main body by a cable (not shown) passing inside the nodal ring 1, and is provided for observation by the user. Also,
Inside the node ring 1, there are various cables such as a fiber for sending light to the lighting window provided at the tip 5 and a pipe for sending water to the water inlet for cleaning the front side of the tip 5. Passing through. The outside of the nodal ring 1 is covered with a flex 12 made of a spirally wound strip-shaped thin metal plate in order to protect the nodal ring 1 and the cables inside it, and the outside is made of knitted thin metal wire. It is covered with a braided blade 13. The outer side of the blade 13 is an elastic coating 4 made of rubber or resin for protecting a living body or a test object as the outermost part.
covered with.

FIG. 6 schematically shows the operation when bending a curved portion consisting only of the node ring 1 and the wire 2. Here, for the sake of simplicity, it is assumed that the curved portion has a structure that bends only in two directions. When one side of the wire 2 is pulled in the direction of arrow F, the nodal ring 1a at the tip bends in the direction of arrow G, as shown in FIG. 6(A). When the wire 2 is further pulled, the nodal ring 1a at the tip comes into contact with the nodal ring 1b behind it at point H, as shown in FIG.
), the node ring 1b begins to bend.

In this way, when the curved portion is composed of only the node ring and the wire, as the wire is pulled, it gradually bends from the node ring at the tip. However, in an actual endoscope, the outer side of the nodal ring is covered with an elastic coating, so the operation as shown in FIG. 6 does not occur.

FIGS. 7A, 7B, and 7C show the operation of the conventional endoscope bending section in three cases. FIG. 7(A) shows a state in which the wire (not shown) is not pulled at all. 7th
When the wire is pulled in FIG. 7(A), the node ring 1a at the tip of the curved portion bends in the direction of arrow G, resulting in a state as shown in FIG. 7(B).

Then, the elastic coating 4 on the outside of the nodal ring has an expanding part and a contracting part, and a restoring force is generated in each part to return to its original state. The part that stretches has an inward pulling force f
1, a force f2 is generated in the contracted portion to push it outward. Then, as shown in Figure 7 (C), these forces also affect the neighboring nodal rings, so that the amount of stretch (or contraction) of the elastic membrane in each nodal ring becomes equal. Therefore, the state shown in FIG. 7(B) cannot be maintained.

In other words, the length Nl in Fig. 7(A) is extended in Fig. 7(B), so that Nl+Δ1
1, but in Fig. 7(C) it also affects the adjacent nodal ring, and in Fig. 7(A) and (B) the length [2(ff2-1
The part that was 1) expands and becomes length g2 + ΔfI2,
The part whose length was fl1 + Δf11 is Jul + Δ! 11
'CΔ11゛<ΔNl). Therefore, Fig. 7 (C
), before the nodal ring at the tip is completely bent, the adjacent nodal ring 1b begins to bend, and as a result, it is difficult to bend a large angle range from the tip of the curved part, as shown in Figure 7 (B). becomes. As a result, the tip of the endoscope cannot be easily directed to a region desired to be observed within a narrow space within the body cavity. Furthermore, although it is possible to increase the volume of the body cavity by pumping more air into the body cavity in order to direct the tip of the scope to the region desired to be observed, this method causes pain to the subject.

(Problems to be Solved by the Invention) As explained above, it is difficult to bend the conventional endoscope from the tip of the curved portion, making observation in a narrow space extremely difficult.

An object of the present invention is to solve the above problems and provide an endoscope that can be easily and smoothly bent from the tip of the curved portion.

[Configuration of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the configuration of the present invention has a ring shape, and a plurality of rings are connected in the direction of the central axis to form a tubular body. and a bending means capable of bending the tubular body; an elastic body surrounding the outer periphery of the tubular body and having a constant elastic modulus; It consists of a first elastic coating whose wall thickness becomes smaller as the closer it gets, and an elastic body surrounding the outer periphery of the first elastic coating and having an elastic modulus smaller than that of the first elastic coating, and at the tip of the tubular body. It is composed of a second elastic coating whose thickness increases as the closer it approaches.

(Function) By making the thickness of the first elastic coating surrounding the outside of the nodal ring of the curved portion of the endoscope smaller toward the tip of the curved portion, the elastic modulus of the elastic coating decreases as it approaches the tip of the curved portion. becomes smaller continuously. As a result, the force generated within the elastic coating becomes smaller as it approaches the tip of the curved portion, and therefore the curved portion can be easily and smoothly bent from the tip. In addition, the first elastic coating has a thinner wall thickness closer to the tip, making it easier to tear, but there is a second elastic coating on the outside of the first elastic coating, which has a thicker wall thickness closer to the tip. By providing the elastic coating, it is possible to provide an endoscope that maintains strength against tearing and can be easily inserted into the subject.

(Example) FIG. 1 shows the configuration of an endoscope bending section according to a first example of the present invention. A plurality of joint rings 1 are connected in the direction of the central axis of the curved part in FIG. 1, and four wires 2 for bending the curved part are each fixed at one end inside the joint ring located at the tip. There is. The outer side of the nodal ring 1 is surrounded by a layer 3 consisting of a flex and a blade, and the outer side of the layer 3 is a first elastic coating 4a.

A second elastic coating 4b is provided on the outside of the first elastic coating 4a.

FIG. 2 is a cross-sectional view of the structure of the endoscope bending section and tip section according to the first embodiment of the present invention, taken along a plane including the central axis of the endoscope. Cables 6 such as wiring, lighting fibers, and water pipes having lenses or openings at the tips 5 run through the central portion. A plurality of joint rings 1 are arranged on the outside of the cables 6, and between the joint rings 1 and the cables 6 there is a wire 2 whose one end is fixed to the joint ring at the tip.
is passing through. A layer 3 consisting of a flex and a blade is provided on the outside of the node ring 1. The outside of the layer 3 is covered with an elastic coating 4a. The elastic coating 4a has an elastic modulus of, for example, a rubber hardness of 60, and is tapered so that the thickness of the most tip part is O', 1 mm, and the thickness of the part 5C1++s away from the tip is, for example, 0.4 mm. It is. Due to the taber of the elastic coating 4a, the elastic coating 4a
Although the rubber hardness of the elastic coating 4a is uniform, the elastic modulus of the elastic coating 4a decreases continuously as it approaches the tip.

This makes it possible to smoothly bend a large angle range near the tip. Here, the elastic coating 4a
The part near the tip is very thin and easily torn. Therefore,
The outside of the elastic coating 4a is covered and protected by another elastic coating 4b. The elastic coating 4b has a rubber hardness of 30, for example, in order to reduce the influence of its elastic force on the bending operation.
It has a smaller elastic modulus than the elastic coating 4a.

The thickness of the elastic coating 4b is 0.4m+* at the tip, and 0.1mm at the portion 50u+ away from the tip.
The combined thickness of the elastic coating 4b and the elastic coating 4b is kept constant, and the elastic coating has a shape that can be easily inserted into the subject while maintaining the thickness of the elastic coating with sufficient strength against tearing.

FIG. 3 schematically shows the operation of the endoscope bending section of the present invention, which is constituted by the node ring 1 and the elastic coating 4a. As shown in FIG. 7, the curved portion has a structure that allows it to bend only in two directions.

In FIG. 3(A), when the wire (not shown) is pulled in the same manner as in FIG. 6, the nodal ring 1a at the tip of the curved portion bends in the direction of the arrow, resulting in a deaf state as shown in FIG. 3(B). Become. here,
Since the elastic modulus of the elastic coating 4a is small, both the inward pulling force fl generated in the extending portion of the elastic coating 4a and the outward pushing force f2 generated in the contracting portion are small, and the elastic coating 4a
Since the elastic modulus of b is large, it does not affect adjacent nodal rings.

When the nodal ring is further bent to a certain angle by pulling a wire (not shown), the elastic coating 4a no longer contracts (or stretches), and only at this point does the adjacent nodal ring change as shown in FIG. 3(C). It starts to curve like this.

FIG. 4 is a sectional view taken along a plane including the central axis of the endoscope, showing the lateral movement of the bending part and the distal end part of the endoscope according to the second embodiment of the present invention. Similar to the one shown in FIG. 2, cables 6 pass through the center, and a plurality of connected nodes 1 are arranged on the outside of the cables 6.
A wire 2, one end of which is fixed to a node ring at the tip, passes between the cables 6 and the cables 6. A layer 3 consisting of a flex and a blade is provided on the outside of the node ring 1. The outside of layer 3 is covered with an elastic coating 4g-. Elastic coating 4a-
The elastic modulus is, for example, a rubber hardness of 30, and it is tapered so that the thickness of the most tip part is, for example, 0.4 mm, and the thickness of the part 50 m+s away from the tip is, for example, 0.1 mm. . The outside of the elastic coating 4b'' is covered with another elastic coating 4.
The elastic coating 4b- has an elastic modulus of, for example, a rubber hardness of 60, and a thickness of, for example, 0.1+1l11 at the most distal end. 4 m.The thickness of the elastic coating 4b-, which has a large elastic modulus, becomes thinner near the tip, and the combined thickness of the elastic coating 4a- and the elastic coating 4b- is always kept constant. As in the first embodiment, this allows the part near the tip to be smoothly bent over a wide range of angles, and can be inserted into the subject while maintaining the thickness of the elastic coating that is strong enough to resist tearing. In addition, in this embodiment, since the rubber hardness of the elastic coating covering the outermost periphery of the curved portion of the endoscope is high, the elastic coating with low rubber hardness covers the outermost periphery. The strength against tearing of the elastic coating is even greater than in the example.

As described above, according to the endoscope of the present invention, it is possible to smoothly bend a large angle range from a portion near the tip of the curved portion with a simple configuration, and the thickness of the elastic coating is sufficient to prevent breakage. It has a shape that makes it easy to insert into the subject while maintaining the

Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without changing the main idea.

For example, instead of the wire in this embodiment,
-Applicable to endoscopes that are bent using a hydraulic system as shown in Publication No. 103430, and endoscopes that are similarly bent using deformation caused by temperature changes in shape memory alloys instead of wires. Can be done.

[Effects of the Invention] As explained above, according to the present invention, the thickness of the first elastic coating covering the outside of the nodal ring of the curved portion of the endoscope is made smaller toward the tip of the endoscope. , it is possible to smoothly bend a large angle range from the part near the tip,
Furthermore, by covering the outside of the first elastic coating with a second elastic coating that is thicker nearer to the tip of the endoscope,
The elastic coating can be shaped to be easily inserted into the subject while maintaining the thickness of the elastic coating with sufficient strength against tearing.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a first embodiment of the present invention, FIG. 2 is a sectional view of the first embodiment of the present invention, FIG. 3 is a schematic diagram showing the operation of the embodiment of the present invention, and FIG. The figure is a sectional view of the second embodiment of the present invention, FIG. 5 is a configuration diagram of a conventional endoscope, and FIG. 6 is a schematic diagram showing the operation when there is no elastic coating on the curved part of the endoscope. FIG. 7 is a schematic diagram showing the operation of a conventional endoscope. 1... Node ring, 2... Wire, 4a, 4b...
・Elastic coating lll3 Figure 6 @

Claims (2)

[Claims] (1) A ring having a ring shape, a plurality of which are connected in the direction of the central axis to form a tubular body, and are rotatably supported; a bending means capable of bending the tubular body; a first elastic coating that surrounds the outer periphery of the tubular body, is made of an elastic body having a constant elastic modulus, and has a thickness that becomes smaller toward the tip of the tubular body, and surrounds the outer periphery of the first elastic coating; An endoscope comprising: a second elastic coating made of an elastic body having a smaller elastic modulus than the first elastic coating, and having a wall thickness that becomes larger nearer to the distal end of the tubular body. (2) a ring having a ring shape, a plurality of which are connected in the direction of the central axis to form a tubular body, and rotatably supported; a bending means capable of bending the tubular body; a first elastic coating that surrounds the outer periphery of the tubular body and becomes thicker toward the tip of the tubular body; and a constant elastic coating that surrounds the outer periphery of the first elastic coating and is larger than the first elastic coating. An endoscope comprising a second elastic coating made of an elastic body having a modulus of elasticity and having a thickness that decreases closer to the distal end of the tubular body.