JP3748957B2 - Endoscope - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an endoscope having a bending portion that can be bent in a desired observation direction, and more particularly to a pressure-resistant structure in a bending portion of an endoscope.
[0002]
[Prior art]
Endoscopes have been widely used in the medical field and industrial field in recent years. For example, some industrial endoscopes used in the industrial field may be used under pressure and under reduced pressure, and the endoscope must be structured to withstand such pressure changes. There is.
[0003]
In general, an endoscope is provided with a bendable bending portion at an elongated insertion portion, and this bending portion has a structure in which an outer periphery of a bending tube formed by connecting a plurality of bending pieces is covered with an elastic tube and a metal mesh tube. In such an endoscope, the elastic tube of the curved portion is most affected by the change in pressure as described above. Under a high pressure exceeding 10 atm, the elastic tube of the bending portion of the endoscope falls into the gap between the metal mesh tubes on the outer periphery of the bending tube, and the elastic tube bulges inwardly like a balloon. When the bending operation is performed, the swelled portion of the elastic tube is sandwiched and cut by the bending tube, which may cause a problem that the watertightness of the endoscope cannot be maintained. Further, similarly to the pressurization, at the time of decompression, there is a possibility that the elastic tube swells to the outside through the gap of the metal mesh tube and bursts.
[0004]
In order to eliminate such problems, conventionally, measures such as increasing the thickness of the elastic tube to make it difficult to bulge have been taken, but in this case, it becomes difficult to bend, and this causes a problem in bending operation. was there.
[0005]
Japanese Patent Application Laid-Open No. 5-103754 discloses a covering structure for an endoscope bending portion having pressure resistance. However, in this structure, since the number of members covering the bending tube is large, the outer portion of the bending portion is not covered. There is a problem that the diameter becomes thick and the curve is difficult to be applied.
[0006]
[Problems to be solved by the invention]
As described above, in the configuration of the conventional bending portion, if sufficient pressure resistance is provided, the number of parts is increased and the outer diameter of the bending portion is increased. There were problems such as becoming.
[0007]
The present invention has been made in view of these circumstances, and is capable of improving pressure resistance at a low cost with a simple structure without increasing the outer diameter of the bending portion or lowering the bending performance. An object of the present invention is to provide an endoscope having a section.
[0008]
[Means for Solving the Problems]
The endoscope of the present invention is an endoscope having a bending portion that can freely change the visual field direction by bending,
A first metal mesh tube formed by braiding a wire bundle in which a plurality of wires made of fine metal wires are arranged on an outer periphery of a bending tube capable of bending the bending portion, an elastic tube including an elastic material, a second tube The metal mesh tube is coated in order, the density ρ of the first metal mesh tube is 0.45 or more, and the density ρ of the first and second metal mesh tubes is 0.85 or less. .
[0009]
With this configuration, the elastic tube is prevented from falling into the gap between the metal mesh tubes without complicating the covering structure.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
1 to 5 relate to a first embodiment of the present invention, FIG. 1 is a perspective view showing the overall configuration of the endoscope, FIG. 2 is a cross-sectional view showing the configuration of a bending portion, and FIG. FIG. 4 is a side view showing the configuration of the metal mesh tube, and FIG. 5 is a cross-sectional view showing the state of the bending portion of the present embodiment during pressurization.
[0011]
In the endoscope 1 of the present embodiment, a flexible snake tube constituting a part of the insertion portion 3 is connected to one end of the operation portion 2, and a bending portion 4 is provided at the distal end side of the flexible snake tube. In addition, a hard tip portion 5 having an objective optical system, an illumination optical system, and the like is connected to the tip thereof. By turning the bending operation knob 6 provided in the operation unit 2, it is possible to remotely bend the bending portion 4 and to direct the distal end hard portion 5 in a desired direction.
[0012]
An eyepiece unit 7 is provided at the other end of the operation unit 2, and the observation site can be imaged from the eyepiece unit 7 by observing with the naked eye or wearing a TV camera. Further, a flexible light guide cable 8 is connected to the operation unit 2, and a connector 9 connected to a light source device (not shown) is provided at an end of the light guide cable 8.
[0013]
As shown in FIG. 2, the bending portion 4 is provided with a bending tube 13 in which a plurality of bending pieces 11 are rotatably connected by rivets 12, and is fixed to the bending piece 11 inside the bending tube 13. A bending wire 15 is disposed so as to pass through the wire receiver 14, and the bending portion 4 is bent by pulling and relaxing the bending wire 15 so that the visual field direction of the endoscope can be freely changed. .
[0014]
The outer periphery of the bending tube 13 is covered with a first metal mesh tube 16, an elastic tube 17, and a second metal mesh tube 18 in this order to form a three-layered tube. In the present embodiment, the density ρ of the first metal mesh tube 16 is 0.45 or more in the curved portion 4 having the above-described configuration. However, the density ρ is expressed by the following equation from the values shown in FIGS.
[0015]
ρ = (dmn) / (2πD cos θ) [mm / mm]
d: Outer diameter of strands of metal mesh tube n: Number of strands (number of strands)
m: Number of strands (number of strands in the strand)
D: inner diameter of metal mesh tube θ: knitting angle of metal mesh tube
3 and 4 show a configuration example of the first metal mesh tube 16, and FIG. 3 is a cross-sectional view. In the example of this figure, the case where the number of strands m = 5 [lines] and the number of strands n = 24 is shown. That is, the first metal mesh tube 16 is formed by braiding a strand bundle 20 in which a plurality of strands 19 made of fine metal wires are arranged, and the strand bundle 20 is a strand 19 having an outer diameter d. The number of strands per round of the metal mesh tube is 24 and the inner diameter is D. Further, as shown in the side view of FIG. 4, the knitting angle of the first metal mesh tube 16 (the angle formed between the wire bundle 20 and the central axis of the metal mesh tube) is θ.
[0017]
In this configuration, the outer diameter d of the strand, the inner diameter D of the metal mesh tube, and the knitting angle θ may be determined so that the density ρ ≧ 0.45 from the above formula. If the density satisfying such conditions is set, the gap 21 of the first metal mesh tube 16 and the gap G between the wire bundles are sufficient so that the elastic tube 17 does not fall inside the first metal mesh tube 16. It will be small.
[0018]
As described above, when the curved portion 4 is configured using the first metal mesh tube 16 having a density ρ larger than 0.45, the elastic tube 17 is the first in the use environment under high pressure as shown in FIG. The metal mesh tube 16 does not fall inward from the gap 21.
[0019]
Here, the density ρ sufficient to prevent the elastic tube from dropping into the metal mesh tube can be obtained as follows.
[0020]
The bending portion 4 of the endoscope is bent in a use environment under high pressure, and it is confirmed whether or not the elastic tube 17 falls into the first metal mesh tube 16, and if it falls, the elastic tube 17 is bent. The occurrence of abnormality is confirmed whether it is pinched by 13 and torn.
[0021]
For example, when the density ρ = 0.43 of the first metal mesh tube 16 is set, according to the experimental results, the elastic tube 17 falls into the gap between the first metal mesh tube 16 in the bending portion 4 and is sandwiched between the bending tubes 13. It will be torn and watertightness will not be maintained.
[0022]
Further, in the case where the density ρ = 0.45 of the first metal mesh tube 16, according to the experimental results, the elastic tube 17 does not fall into the gap between the first metal mesh tube 16 in the curved portion 4, Watertightness is maintained without breaking the elastic tube 17.
[0023]
From the above results, if the density ρ of the first metal mesh tube 16 is 0.45 or more, the elastic tube 17 swells even under high pressure and falls into the first metal mesh tube 16 to be damaged. Without this, the water tightness of the bending portion 4 of the endoscope is always maintained. In this case, the structure of the covering tube of the bending portion 4 is complicated, the outer diameter is not increased, and the bending performance is not deteriorated.
[0024]
For comparison, an example in which the density ρ <0.45 of the metal mesh tube is shown in FIGS. 6 and 7. As can be seen from the side view of FIG. 6, in the metal mesh tube 51 having a density ρ smaller than 0.45, the gap 52 becomes large, so that the elastic tube 17 easily falls into the metal mesh tube 51. When the bending portion 4 is configured using such a metal mesh tube 51, the elastic tube 17 falls inward from the gap 52 of the metal mesh tube 51 in a use environment under high pressure as shown in FIG.
[0025]
At this time, as shown in FIG. 8, the spacing between the wire bundles of the metal mesh tube 51 is as large as 2 mm, for example, and the elastic tube 17 falls into the gap 52 of the metal mesh tube 51 and bulges inward to form the bending piece 11. There is a risk of being pinched between them or being damaged by the bending wire 15.
[0026]
According to the configuration of the bending portion of the present embodiment, the elastic tube does not swell even in a use environment under high pressure, and does not fall into the inside of the first metal mesh tube and be damaged. The pressure resistance of the curved portion of the endoscope can be improved. Further, at this time, it is possible to prevent the bending performance from deteriorating without increasing the number of components of the bending portion or complicating the structure of the covering tube and increasing the outer diameter.
[0027]
The second embodiment is configured by setting the density ρ of the second metal mesh tube 18 to 0.45 or more in the bending portion 4 of the first embodiment. In this configuration, contrary to the first embodiment, the elastic tube 17 does not swell outward from the gap between the second metal mesh tubes 18 during decompression, and is not ruptured. The watertightness of the is kept.
[0028]
Therefore, according to the second embodiment, the elastic tube does not swell and fall outside the second metal mesh tube even in a use environment under high decompression, and it is as simple as the first embodiment. The pressure resistance of the bending portion of the endoscope can be improved at a low cost with a simple structure, and at this time, the number of components of the bending portion may increase or the structure of the coated tube may become complicated and the outer diameter may increase. Therefore, it is possible to prevent the bending performance from being lowered.
[0029]
The third embodiment is configured by setting the density ρ of the first metal mesh tube 16 and the second metal mesh tube 18 to 0.45 or more in the bending portion 4 of the first embodiment. . In this configuration, the effects of both the first embodiment and the second embodiment are obtained, and the water tightness of the endoscope is maintained even under high pressure and high pressure reduction.
[0030]
Therefore, according to the third embodiment, the elastic tube does not swell and fall into the first and second metal mesh tubes even under a high pressure and high pressure environment, so that the first implementation is not performed. As with the configuration, the pressure resistance of the bending portion of the endoscope can be improved at low cost with a simple structure, and at this time, the number of components of the bending portion increases or the structure of the coated tube becomes complicated, resulting in a large outer diameter. It is possible to prevent the bending performance from being lowered without increasing the diameter.
[0031]
The fourth embodiment is configured by setting the density ρ of at least one of the first metal mesh tube 16 and the second metal mesh tube 18 to 0.85 or less in the configuration of the first to third embodiments. It is a thing. As described above, if the density ρ of the metal mesh tubes 16 and 18 is 0.85 or less, the density is not too high and the metal mesh tube does not become hard. Therefore, the function and effect of the first to third embodiments are eliminated. In addition, a desired bending angle can be obtained without impairing the flexibility of the bending portion 4 of the endoscope. If the density ρ of the metal mesh tube is larger than 0.85, it is difficult to bend the endoscope, which may hinder the bending operation.
[0032]
Therefore, according to the fourth embodiment, since the bending portion can be prevented from hardening by setting the upper limit of the density of the metal mesh tube, the bending portion of the endoscope in a use environment under a high pressure with a simple structure. The pressure resistance can be improved, and deterioration of the bending performance and operability can be prevented so that a desired bending state can be obtained.
[0033]
In the bending portion 4 of the first embodiment, the fifth embodiment includes a plurality of wire bundles 20 formed by braiding at least one metal mesh tube of the first metal mesh tube 16 and the second metal mesh tube 18. The gap G is set to 0.8 mm or less. In this configuration, similarly to the first to third embodiments, the elastic tube 17 does not fall into the gap between the metal mesh tubes 16 and 18 even with the thickness of the elastic tube normally used.
[0034]
Therefore, according to the fifth embodiment, it is possible to reliably prevent the elastic tube from falling into the gap between the metal mesh tubes, so that the elastic tube swells and falls into the metal mesh tube even under a high-pressure use environment and is damaged. In addition, the pressure resistance of the bending portion of the endoscope can be improved at a low cost with a simple structure as in the first embodiment, and at this time, the number of components of the bending portion increases or the structure of the coated tube It is possible to prevent the bending performance from being lowered without complicating and increasing the outer diameter.
[0035]
Next, a configuration example of an image guide fiber and a light guide fiber disposed in the insertion portion 3 of the endoscope 1 is shown.
[0036]
The elastic tube that coats the outer periphery of the image guide fiber, light guide fiber, etc. could use a material with air permeability, but the conventional configuration cannot cope with a sudden change in pressure, and the elastic tube There is a risk that the image guide fiber and the light guide fiber will break due to puncture or expansion / contraction of the elastic tube. In view of the above circumstances, a configuration example of an endoscope having an elastic tube that does not damage the endoscope's built-in object even when the pressure changes suddenly during use will be described below.
[0037]
The first configuration example is a configuration example of an image guide fiber 31 that constitutes an observation optical system of an endoscope as shown in FIG. 9, and the outer periphery of the image guide fiber 31 is provided by being covered with an elastic tube 32. The elastic tube 32 is provided with a plurality of vent holes 33 substantially uniformly over its entire length.
[0038]
By using the elastic tube 32 provided with the vent hole 33 in this way, the elastic tube 32 covered on the outer periphery of the image guide fiber 31 is punctured due to a sudden change in pressure, or the image is caused by expansion / contraction of the elastic tube 32. It is possible to prevent the guide fiber from being broken. Therefore, according to the present configuration example, the image guide fiber covered with the elastic tube can be prevented from being damaged due to a sudden change in pressure during use.
[0039]
The second configuration example is a configuration example of the light guide fiber constituting the illumination optical system of the endoscope. Like the image guide fiber of the first configuration example, the elastic tube that covers the outer periphery of the light guide fiber is provided. A plurality of ventilation holes are provided over the entire length.
[0040]
According to the second configuration example, the elastic tube covered on the outer periphery of the light guide fiber is prevented from being punctured due to a sudden change in pressure, and the light guide fiber is not broken due to expansion / contraction of the elastic tube. In the light guide fiber covered with an elastic tube, it is possible to prevent damage to a sudden change in pressure during use.
[0041]
[Appendix]
(1) In an endoscope having a bending portion that can freely change the viewing direction by bending,
A first metal mesh tube formed by braiding a wire bundle in which a plurality of wires made of fine metal wires are arranged on an outer periphery of a bendable bending tube, an elastic tube including an elastic material, and a second tube The metal mesh tube is coated in this order, and the density ρ of at least one of the metal mesh tubes is 0.45 or more,
However, ρ = (dmn) / (2πD cos θ) [mm / mm]
d: Wire outer diameter of metal mesh tube n: Number of strands (number of strands)
m: Number of strands (number of strands in the strand)
D: Internal diameter of metal mesh tube θ: Endoscope characterized by knitting angle of metal mesh tube.
[0042]
(2) The endoscope according to appendix 1, wherein a density ρ of at least one of the metal mesh tubes is 0.85 or less.
[0043]
(3) The endoscope according to appendix 1, wherein a gap between a plurality of braided wire bundles of at least one of the metal mesh tubes is 0.8 mm or less.
[0044]
(4) An endoscope comprising an elastic tube that covers an outer periphery of a built-in object disposed inside the endoscope insertion portion, and a vent hole is provided over the entire length of the elastic tube.
[0045]
(5) The appendix 4 is characterized in that the elastic tube covers an outer periphery of at least one of an image guide fiber constituting an observation optical system of an endoscope and a light guide fiber constituting an illumination optical system. The endoscope described.
[0046]
【The invention's effect】
As described above, according to the present invention, there is an effect that the pressure resistance can be improved at low cost with a simple structure without increasing the outer diameter of the bending portion or lowering the bending performance.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an overall configuration of an endoscope according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a configuration of a bending portion according to the embodiment of the present invention. FIG. 4 is a side view showing the configuration of the metal mesh tube of the present embodiment. FIG. 5 is a sectional view showing the state of the bending portion of the embodiment during pressurization. FIG. 7 is a side view showing a configuration example of a metal mesh tube when the density ρ of the mesh tube is made smaller than 0.45. FIG. FIG. 8 is an explanatory view showing a state in which the elastic tube swells in the curved portion when the density ρ of the metal mesh tube is made smaller than 0.45. FIG. 9 shows the observation optical system of the endoscope. A plurality of vent holes are provided over the entire length of the elastic tube covering the outer periphery of the image guide fiber Explanatory view showing a configuration example was EXPLANATION OF REFERENCE NUMERALS
DESCRIPTION OF SYMBOLS 3 ... Insertion part 4 ... Bending part 13 ... Bending pipe 15 ... Bending wire 16 ... 1st metal mesh pipe 17 ... Elastic tube 18 ... 2nd metal mesh pipe 19 ... Strand 20 ... Strand bundle 21 ... Gap

Claims (1)

In an endoscope having a bending portion that can freely change the viewing direction by bending,
A first metal mesh tube formed by braiding a wire bundle in which a plurality of wires made of fine metal wires are arranged on an outer periphery of a bending tube capable of bending the bending portion, an elastic tube including an elastic material, a second tube A metal mesh tube is coated in order, and the density ρ of the first metal mesh tube is 0.45 or more, the density ρ of the first and second metal mesh tubes is 0.85 or less ,
However, ρ = (dmn) / (2πD cos θ) [mm / mm]
d: Wire outer diameter of metal mesh tube
n: Number of strands (number of strands)
m: Number of strands (number of strands in the strand)
D: Inner diameter of metal mesh tube
θ: An endoscope characterized by a knitting angle of a metal mesh tube.

Images