JPH0783740B2 - Flexible tube for endoscope - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a flexible tube of an endoscope used for observing the inside of a living body cavity or the inside of a machine, and particularly constitutes a flexible tube. The present invention relates to a flexible tube in which the braid angle of the wire of the reticulated tube is improved to improve the durability against bending.

[Prior Art] A 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. Therefore, the flexible tube is required to have sufficient durability against bending so as not to be buckled or otherwise damaged by bending.

In the conventional flexible tube, a plurality of wires made of thin metal wires are braided to form a mesh tube, the spiral tube is covered with the mesh tube, and a flexible outer skin is formed on the circumference. The reticulated tube was covered with braided wire at an angle of 30 to 45 degrees with respect to the tube axis direction of the flexible tube.

[Problems to be Solved by the Invention] When a conventional flexible tube is bent with a small radius of curvature, as shown in FIG. 5, a wrinkle s is generated in the outer skin portion inside the curve and the flexible tube a is seated. It yielded and was damaged.

The inventor found out that the braid angle of the wires forming the reticulated tube is greatly involved in the occurrence of the wrinkles. This will be described with reference to FIG. 6. When looking at one of the wires b of the braided tube braided in the flexible tube a from the side, the wires b form a substantially sine curve. ing.

The two-dot chain line shows the state when the flexible tube a is bent, and the flexible tube a shrinks on the inner peripheral side and extends on the outer peripheral side in the curved portion. However, a flexible tube having a structure in which a spiral tube is covered with a mesh tube has a spiral tube and a mesh tube that are fixed to each other by soldering at both ends of the structure. Movement is restricted in the direction. Therefore, when the flexible tube a is bent, the expansion on the outer peripheral side is small with respect to the contraction on the inner peripheral side, and it can be considered that it does not expand at all on the outer peripheral side.

Referring again to FIG. 6, when the flexible tube a is bent as shown by the chain double-dashed line, the inner peripheral side of the flexible tube a contracts, so that the length of the wire b of the reticulated tube is relatively excessive. As a result, the wire b of the reticulated tube tries to float inward by δ as shown by the dotted line and presses the outer skin c. This is one of the major causes of wrinkling in the flexible tube, and wrinkling occurs when the outer cover c cannot withstand the internal pressure of the mesh tube.

When the braid angle θ of the wire b of the reticulated tube is changed and shown in FIG. 7, when θ = 30 degrees, FIG. 8 when θ = 40 degrees, and FIG. 9 when θ = 60 degrees ( θ is the angle between the wire b and the tube axis d of the flexible tube) As is clear from the above figures, the smaller the angle θ between the wire b of the reticulated tube and the tube axis d of the flexible tube, the smaller The amount of floating δ of the wire b during bending is large, and wrinkles are likely to occur in the flexible tube.

The results of the experiment conducted by the inventor with various changes of the angle θ formed by the wire b of the reticulated tube and the tube axis d of the flexible tube were as follows.

θ = 30 °… Wrinkle immediately occurs θ = 40 °… Wrinkle occurs due to repeated bending θ = 45 °… Wrinkle sometimes occurs due to repeated bending θ = 50 °… Almost no wrinkle occurs θ = 55 °… No wrinkle occurs θ = 60 degrees ... Wrinkles do not occur at all. As is clear from this result, when the angle between the wire rod b of the reticulated tube and the tube axis d of the flexible tube is 45 degrees or less, repeated bending causes Wrinkles easily occur in the flexible tube, the conventional flexible tube whose angle was 30 degrees to 45 degrees, by being repeatedly bent when passing through the lumen of the body cavity, such as the duodenum or large intestine, There was a defect that wrinkles occurred, buckled, damaged, and unusable.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the conventional drawbacks described above, and to provide a flexible tube for an endoscope which is free from wrinkles even when subjected to repeated bending and has excellent durability against bending.

[Means for Solving Problems] A flexible tube of an endoscope of the present invention for achieving the above object will be described with reference to FIG. 1 corresponding to an embodiment. Is formed by braiding a plurality of strands 12a ..., and the flexible tube 1 has a single reticulated tube 12 that covers the outer circumference of the spiral tube 11 in a single layer, and further has flexibility on the outer circumference. The outer tube 13 is covered, and the mesh tube 12 is a wire.
12a ... is braided at an angle of more than 45 degrees and not more than 65 degrees with respect to the direction of the tube axis 14 of the flexible tube.

[Operation] When the flexible tube 1 is bent, the wire 12a of the reticulated tube becomes δ in FIG.
Only the outer skin 13 is locally pressed outward to try to float up inside the curve. However, the lifting amount of the wire 12a is 1
Flexible tube 1 because it is not enough to cause wrinkles
Wrinkles do not occur even when repeatedly bent.

[Embodiment] An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 2 shows the overall configuration of an endoscope that employs the flexible tube 1 of the present embodiment. The flexible tube 1 connected to the operation section 2 is provided at the operation section 2 at the tip thereof. A bending portion 4 that is remotely bent by rotating the bending operation knob 3 is formed, and a tip end main body 5 including an objective optical system and the like is connected to the tip end thereof. A connector 7 connected to a light source device (not shown) is connected to an end portion of the flexible connection cord 6 connected to the operation unit 2.

FIG. 1 shows the configuration of the flexible tube 1 of this embodiment, and 11 is a known spiral tube formed of a metal band such as a copper alloy or stainless steel. It should be noted that the spiral tube 11 may have a single winding or multiple windings of two or more layers. Reference numeral 12 denotes a reticulated tube coated on the outer periphery thereof. The reticulated tube 12 is formed by braiding a plurality of metal wires 12a ... The wires 12a ... Are braided so that the angle θ is about 55 degrees with respect to the direction of the tube axis 14 of the flexible tube. The spiral tube 11 and the mesh tube 12 are fixed to each other by soldering or the like at both ends such that the mesh tube 12 is closely attached to the outer periphery of the spiral tube 11 (not shown).

Reference numeral 13 denotes a flexible outer cover which is coated on the outer periphery of the reticulated tube 12. The outer cover 13 is made of, for example, a polyurethane resin or other synthetic resin or a rubber material, and the outer cover 13 formed in a tubular shape in advance is reticulated It is obtained by a method of coating the outer periphery of the tube 12 or coating the outer periphery of the reticulated tube 12 with a resin melted by heating with an extruder.

Next, the operation of the above-described embodiment will be described with reference to FIG. 3. When one of the wire rods 12a of the braided tube braided in the flexible tube 1 is focused and viewed from the side, The line 12a draws a substantially sine curve. When the flexible tube 1 is bent as shown by the chain double-dashed line, the wire 12 tries to float inward by δ as shown by the dotted line, and locally presses the outer skin 13 outward. However, in the case of θ = 55 degrees, the floating amount δ of the wire 12a is not an amount enough to cause wrinkles in the outer skin 13, and therefore wrinkles do not occur even if the flexible tube 1 is repeatedly bent.

In the above embodiment, the angle between the wire 12a of the reticulated tube and the tube axial direction 14 of the flexible tube is θ = 55 degrees, but the present invention is not limited to this and θ If the angle is 50 degrees or more, the wrinkles hardly occur in practical use, and depending on the usage conditions, wrinkles may not occur if θ exceeds 45 degrees, and the object of the present invention can be achieved. .

By the way, when assembling the flexible tube 1, there is a step of first covering the spiral tube 11 with the mesh tube 12. The work there is as shown in FIG. 4. (A) First, the mesh tube 12 is compressed in the axial direction to make the inner diameter thick and the spiral tube 11 is inserted therein. (B) Then, the mesh tube The tube (12) is pulled in the axial direction to make the inner diameter narrower so as to be in close contact with the outer circumference of the spiral tube (11) and fixed at both ends.

In order to assemble by such a process, a mesh tube
When 12 is axially compressed, its inside diameter must be large to some extent, and if θ is 60 degrees or less, that condition is satisfied, but if θ exceeds 65 degrees, the change in the inside diameter becomes small. Therefore, it becomes extremely difficult to insert the spiral tube 11 into the reticulated tube 12.

Therefore, θ is required to be 65 degrees or less in terms of assembly, and θ is more preferably 60 degrees or less in consideration of the fact that as θ increases, the strength against torsion decreases.

Although the flexible tube of the present invention is not used in the connector connecting cord 6 in the above embodiment, the present invention may be applied to the connector connecting cord.

EFFECTS OF THE INVENTION According to the flexible tube of the endoscope of the present invention, wrinkles do not occur even when floating repeatedly, so that there is no accident of buckling or breakage due to repeated bending, which has been frequent in the past. This has the effect of significantly improving the durability of the flexible tube.

[Brief description of drawings]

FIG. 1 is a side view showing a flexible tube according to an embodiment of the present invention by cutting off a part thereof, FIG. 2 is a schematic view of an endoscope adopting the flexible tube, and FIG. FIG. 4 is a schematic view showing the state of the wire of the mesh tube in the flexible tube, FIG. 4 is a schematic view of the process of coating the spiral tube with the mesh tube in the flexible tube, and FIG. 5 is a conventional flexible tube. FIG. 6 is a side view when the tube is bent, FIG. 6 is a schematic view showing the state of the wire of the reticulated tube in the flexible tube, and FIGS. 7 to 9 are cases where the braid angle of the wire is changed. It is a schematic diagram showing the state of. 1 ... Flexible tube, 11 ... Spiral tube, 12 ... Mesh tube, 12a ...
Strands, 13 ... Outer skin, 14 ... Pipe axis

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-59-46931 (JP, A) JP-A-53-106139 (JP, A) JP-A-59-151933 (JP, A) JP-A-57- 195434 (JP, A) JP 59-36 (JP, A) Actually opened 54-80290 (JP, U) Actually opened 57-97505 (JP, U)

Claims (3)

[Claims] 1. A single reticulated tube formed by braiding a plurality of strands of thin metal wire to cover the outer periphery of a spiral tube with a single layer,
Further, in the flexible tube used for the exterior part of the endoscope, which is formed by coating the outer periphery with flexibility, the mesh tube has a wire that exceeds 45 degrees with respect to the tube axis direction of the flexible tube. A flexible tube for an endoscope, which is constructed by braiding at an angle of 65 degrees or less. 2. The endoscope according to claim 1, wherein the reticulated tube is constructed by braiding strands at an angle of 50 to 60 degrees with respect to the tube axis direction of the flexible tube. Flexible tube. 3. The endoscope tube according to claim 1, wherein the mesh tube is formed by braiding strands at an angle of about 55 degrees with respect to the tube axis direction of the flexible tube. Flexible tube.