JPH0975298A - Mesh-like tube for flexible tube of endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mesh-like tube for a flexible tube of an endoscope which has a higher bonding strength with a skin and is bendable smoothly when assembled into the flexible tube. SOLUTION: The outer circumference of a spiral pipe is covered with a mesh-like tube 20 formed by braiding in strand bundles 21 in which filaments are arranged in plurality with the width of the strand larger than the thickness thereof and the shape of a cross section thereof flat and moreover, the mesh-like tube 20 composes a flexible tube 1 of an endoscope by covering the outer circumference thereof with a flexible skin 30 made of a synthetic resin. In work with an angle of braiding of 45 deg.-65 deg., a braiding density of 0.78-0.90 and the frequency of braiding of 24 in bundle, when the width of the strand of the mesh-like tube 20 is represented by A, the number (n) of braids held per average braiding diameter D of the mesh-shaped tube 20 is in a range of 0.058D/A<n<0.128D/A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reticulated tube for a flexible tube used as an exterior part of an endoscope.

[0002]

2. Description of the Related Art Generally, a flexible tube of an endoscope is formed by coating a mesh tube formed by braiding a plurality of wire bundles in which a plurality of thin wires are juxtaposed on the outer circumference of a spiral tube and further flexing the outer circumference thereof. It is formed by covering a synthetic resin outer shell having properties.

As shown in FIG. 7, for example, in Japanese Unexamined Patent Publication No. 1-223923, the total length L of the intersecting portions of the wire bundles 21 in the axial direction of the mesh tube 20 is the axial line of the flexible tube. It is described that the ratio to the total length is 73% to 83%.

If this is replaced with a braid density K (K = (S-s) / S in FIG. 8) which is the ratio of the area where each wire bundle 21 covers the outer peripheral surface of the mesh tube 20, 1- (1 Since −0.73) ² = 0.9271 1- (1-0.83) ² = 0.9711, 0.927 ≦ K ≦ 0.971.
When there is no gap between the wire bundles 21, s = 0 and K = 1.

[0005]

The flexible tube of an endoscope is used while being repeatedly bent with a small radius of curvature in a living body cavity or the like, but as described above, it has a large braid density and a small mesh shape. A flexible tube using a pipe has a weak binding force between the mesh tube and the outer skin, so the outer skin easily separates from the mesh tube when bent with a small radius of curvature, and as a result, wrinkles occur on the outer skin portion that is inside the curve. And, I often buckle.

Further, in order to strengthen the binding force between the mesh tube and the outer shell, the braid density of the mesh tube is made extremely sparse so that the softened or melted outer shell member is eroded well in the gap of the mesh tube. The member penetrates into the spiral tube portion inside the mesh tube, and the flexible tube does not bend smoothly, making it useless.

Therefore, an object of the present invention is to provide a reticulated tube for a flexible tube of an endoscope, which has a strong coupling force with an outer cover when incorporated in a flexible tube and can be smoothly bent.

[0008]

In order to achieve the above object, a reticulated tube for a flexible tube of an endoscope according to the present invention comprises a plurality of thin wires each having a flat cross-sectional shape in which the width of the wire is larger than the thickness of the wire. The flexibility of an endoscope in which a reticulated tube formed by braiding a plurality of juxtaposed wire bundles is covered on the outer circumference of a spiral tube, and the outer circumference of the reticulated tube is covered with a synthetic resin outer cover having flexibility. A braided tube for constructing a tube having a braid angle of 45 ° to 65 °.
°, braid density 0.78 to 0.90, braid count 2
In the case of four bundles, when the width of the wire of the braided tube is A, the number of braids n with respect to the average diameter D of the braided tube of the braided tube is n.
Is in the range of 0.058 D / A ≦ n ≦ 0.128 D / A.

[0009]

Embodiments will be described with reference to the drawings. FIG. 3 shows the entire configuration of the endoscope. A bending operation knob 3 provided on the operation unit 2 is turned around a distal end portion of a flexible tube 1 that covers an insertion unit connected to the operation unit 2. A curved portion 4 that is remotely bent by being moved is formed.

A tip portion main body 5 incorporating an objective optical system and the like is connected to the tip portion side of the bending portion 4.
A connector 7 connected to a light source device (not shown) is connected to an end of the flexible connection cord 6 connected to the operation unit 2.

FIG. 1 is a partial side view showing a part of the flexible tube 1 cut away, and FIG. 2 is a partial side sectional view of the flexible tube 1. 10
Is a spiral tube formed by spirally winding a metal band such as stainless steel or a copper alloy with a uniform diameter, and is formed by single winding or double or multiple winding.

Reference numeral 20 denotes a reticulated tube which is coated on the outer circumference of the spiral tube 10 and is formed by braiding a plurality of wire bundles 21 in which a plurality of metal wires such as stainless steel or copper alloy are arranged in parallel. ing.

The flexible tube 1 of the endoscope must be flexible and resistant to twisting, and must be thin in order to make the inner diameter as thick as possible and the outer shape as thin as possible.
Therefore, the wire of the reticulated tube 20 is, as shown in FIG.
It is effective to use a strand having a width A larger than the thickness B and a flat cross-sectional shape, and such a flat strand is used in the present invention.

The number of strands contained in one bundle of strands 21 constituting the reticulated tube 20 is called a number n, and FIG. 2 shows a case where the number n is 3 = n. Further, the number of braided wire bundles 21 is referred to as the number of strokes m. In the present invention, the braid striking number m is m = 24.

Reference numeral 30 denotes a flexible outer cover that covers the outer periphery of the reticulated tube 20, and is made of, for example, a synthetic resin such as polyurethane resin and penetrates into the gap of the reticulated tube 20 from the outer surface side.

The spiral tube 10 and the mesh tube 20 are the spiral tube 10
The reticulated tube 20 is closely attached to the outer periphery of and is fixed to each other at both ends by soldering or the like. This prevents the flexible tube 1 from stretching and twisting. The angle α formed by each wire of the wire bundle 21 with respect to the axis 40 of the flexible tube 1 in this state is called a braid angle.

The braid angle α of the reticulated tube 20 for the flexible tube of the endoscope
In order to prevent buckling from occurring when the flexible tube 1 is repeatedly bent with a small radius of curvature, 45 ° to 6 °
It is known that the angle should be set within a range of 5 ° (Japanese Patent Laid-Open No. Sho 6).
2-133925).

Further, in order that the binding force between the reticulated tube 20 and the outer cover 30 is strong and the flexible tube 1 can be smoothly bent, when the braid density of the reticulated tube 20 is K, K in a range of 0.78 ≦ K ≦ 0.90 (strictly, 0.
The inventors of the present application have found that it should be set within the range of 772 ≦ K ≦ 0.906), and have already filed a patent application (Japanese Patent Application No. 7-206878).

As described above, the braid density K is equal to the wire bundle 21.
Is the ratio of the area covering the outer peripheral surface of the reticulated tube 20 (K = 1 when there is no gap), and in FIG. 8, K = (S−s) /
S.

Here, it is known that the braid density K is expressed by K = 2F-F ² ... F = m · n · dw / (2P · sin α). However, F: Filling factor m: Number of braids striking n: Number of braids held dw: Diameter of strands [mm] when the cross-sectional shape of the strands of the reticulated tube 20 is circular. P: Braid pitch [mm].

However, in the present invention, since the cross-sectional shape of the wire of the reticulated tube 20 is flat and the braid density is concerned with the width A instead of the diameter dw of the wire, the formula is as follows: Can be rewritten as

F = mnA / (2Psinα) ... 'In addition, since P = πD / tanα ..., from n' (2πsinαF) D / A m · tan α ... However, D: average diameter of braid of reticulated tube 20 (outer diameter of spiral tube 10 + 2
B) [mm]. The strand thickness B is thus related to the average braid diameter D of the braided tube 20.

Therefore, 0.772 ≦ K ≦ for K
The condition of 0.906 and the value of F obtained from the formula,
By substituting the condition of 45 ° <α <65 ° for α into the equation, the number n of braids with respect to the average diameter D of the braid of the reticulated tube 20 is calculated within the following range.

0.058 D / A ≦ n ≦ 0.128 D / A However, n is an integer because it is the number of braids. The present invention may be applied with the connecting cord 6 having the same configuration as that of the flexible tube 1 described above.

[0025]

Example 1 The wire of the reticulated tube 20 has a diameter of 0.08.
A thin metal wire made of a stainless steel wire or a copper alloy wire having a size of 0.1 mm is roller-rolled to have a width (A) × thickness (B) of 0.11.
An element wire having a flat cross section of mm × 0.05 mm was used.

Therefore, the average diameter D of the braid of the reticulated tube 20 is 6.5 mm, the number of braid shots m is 24 bundles, and the braid angle α is 45 °.
<Α <65 °, braid density K is 0.772 ≦ K ≦
The number n of braids of the reticulated tube 20 satisfying the condition in the range of 0.906 is shown in the diagram of FIG. 4 showing the relationship between α, K and n.
Therefore, it must be in the range of 4 ≦ n ≦ 7. Note that the numbers in the diagram represent the braid density K in% (the same applies to FIGS. 5 and 6).

[0027]

Example 2 The wire of the reticulated tube 20 has a diameter of 0.08.
A thin metal wire made of a stainless steel wire or a copper alloy wire having a size of 0.1 mm is roller-rolled to have a width (A) × thickness (B) of 0.11.
An element wire having a flat cross section of mm × 0.05 mm was used.

Therefore, the average diameter D of the braid of the reticulated tube 20 is 4.5 mm, the number of braid shots m is 24, and the braid angle α is 45 °.
<Α <65 °, braid density K is 0.772 ≦ K ≦
The number n of braids of the reticulated tube 20 satisfying the condition within the range of 0.906 is shown in FIG. 5 which is a diagram showing the relationship between α, K and n.
Therefore, it must be within the range of 3 ≦ n ≦ 5.

[0029]

[Third Embodiment] The wire of the reticulated tube 20 has a diameter of 0.05.
A metal thin wire made of a stainless steel wire or a copper alloy wire having a width of mm is rolled into a width (A) × thickness (B) of 0.08.
A wire having a flat cross section of 9 mm × 0.022 mm was used.

Therefore, the average diameter D of the braid of the reticulated tube 20 is 3
mm, braid count m is 24 bundles, and braid angle α is 45 ° <α <
In the range of 65 °, the braid density K is 0.772 ≦ K ≦ 0.90
The number of braids of the braided tube 20 satisfying the condition in the range of 6 n
From FIG. 6, which shows the relationship between α, K, and n by a diagram,
It must be in the range of 2 ≦ n ≦ 4.

[0031]

According to the present invention, in a braided tube for a flexible tube of an endoscope having a braided number of 24 bundles using a flat element wire, the number of braided wires with respect to the average diameter of the braided tube is determined by the braided wire number of the braided tube. Since the braid angle of 45 ° to 65 ° and the braid density of 0.78 to 0.90 are both satisfied by defining the braid angle in a predetermined range corresponding to the diameter, The flexible tube has a strong binding force with the outer skin and can be bent smoothly, and the flexible tube can have excellent durability.

[Brief description of drawings]

FIG. 1 is a partial side view showing a flexible tube of an endoscope according to an embodiment of the present invention by cutting away a part thereof.

FIG. 2 is a partial side sectional view of an embodiment of a flexible tube of an endoscope of the present invention.

FIG. 3 is a side view of an embodiment of an endoscope to which the present invention is applied.

FIG. 4 is a diagram showing a range of the number of braided net-like tubes of the first embodiment of the present invention.

FIG. 5 is a diagram showing a range of the number of braided braided net-like tubes according to the second embodiment of the present invention.

FIG. 6 is a diagram showing a range of the number of braided net-like tubes of a third embodiment of the present invention.

FIG. 7 is a partial side view of a mesh tube.

FIG. 8 is an explanatory diagram of a braid density of a mesh tube.

[Explanation of symbols]

 1 flexible tube 10 spiral tube 20 mesh tube 21 wire bundle 30 outer skin

Claims (1)

[Claims] 1. A reticulated tube formed by braiding a plurality of wire bundles in which a plurality of thin wires having a flat cross-sectional shape in which the width of the wire is larger than the thickness of the wire is braided, and the outer circumference of the spiral tube is further covered. A reticulated tube for forming a flexible tube of an endoscope, the outer surface of which is covered with a flexible synthetic resin outer cover, the braid angle is 45 ° to 65 °, and the braid density is 0. When the number of braids is 78 to 0.90 and the number of braids is 24, when the width of the wire of the reticulated tube is A, the number n of braids with respect to the average diameter D of the braided tube is 0.058 D / A ≦ A reticulated tube for a flexible tube of an endoscope, characterized in that n ≦ 0.128 D / A.