JPH11104066A - Flexible tube of endoscope and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optionally control the axial bending characteristic of a flexible tube through the simple operation of forming a thin-walled part in part of an outer cover layer and of cutting the outer cover layer and very stably maintain the required bending characteristic. SOLUTION: An outer cover layer 11 is laid over a flexible tube component 16 by a molding machine 20 to form a flexible tube 10. A blade 30 is then driven into the outer cover layer 11 up to a predetermined depth to cut and remove a part of the outer cover layer 11. By displacing the blade 30 in the direction to leave the flexible tube 10 according to the feed of the flexible tube 10, a thin-walled part 11a by which the hardness of the flexible tube 10 in the curving direction is changed axially is formed in the outer cover layer 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible tube used as a flexible tube portion of an insertion portion or a flexible portion of a light guide in an endoscope.

[0002]

2. Description of the Related Art As shown in FIG. 5, an endoscope used for medical or industrial purposes has a main body operation section 2 connected to a base end of an insertion section 1 inserted into a body cavity or the like. Further, a light guide flexible portion 3 which is detachably connected to a light source device (not shown) is connected to the main body operation portion 2. The insertion portion 1 has a flexible tube portion 1a for most of the length from the side connected to the main body operation portion 2, and the flexible tube portion 1a is configured to bend in an arbitrary direction along the insertion path. ing. Also,
An angle portion 1b is provided at the distal end of the flexible tube portion 1a, and a distal end hard portion 1c is connected to the angle portion 1b. The rigid end portion 1c is provided with an endoscope observation mechanism and the like.
b is configured to be bendable by remote operation by the main body operation unit 2.

Although not shown, a light guide and an image guide (in the case of an optical endoscope) are provided from the flexible tube portion 1a constituting the insertion portion 1 to the distal end hard portion 1c via the angle portion 1b. The optical fiber to be composed and the hard tip portion 1c
Is equipped with a solid-state imaging device such as a CCD,
A signal cable (in the case of an electronic endoscope) connected to the solid-state imaging device, a treatment tool insertion channel for leading out a treatment tool such as forceps, a tube including an air supply / water supply pipe, and other long-sized devices The insertion member is inserted. on the other hand,
The light guide is inserted into the light guide flexible portion 3, and an air supply / water supply pipe and the like are also inserted. Further, in the case of an electronic endoscope, the flexible light guide 3 is connected not only to the light source device but also to the processor, so that a signal cable is also inserted through the flexible flexible light guide 3. . As described above, each of the insertion members inside the endoscope has a flexible structure.

As described above, the flexible tube portion 1a, the angle portion 1b, and the light guide flexible portion 3 have various insertion members inserted therein, and these insertion members are soft members due to their properties. It is. For this purpose, the flexible tube portion 1a, the angle portion 1b, and the light guide flexible portion 3 must be provided with a condition that the member has flexibility in the bending direction and protects a member inserted therein. In order to achieve this, it must have shape retention, that is, crush resistance. For this, they are formed of flexible tubes. The angle portion 1b is bent by remote control, but the flexible tube portion 1a and the light guide flexible portion 3 only need to bend when an external force is applied.

FIG. 6 shows the structure of a flexible tube used as the flexible tube portion 1a and the light guide flexible portion 3. Here, the flexible tube portion 1a and the light guide flexible portion 3 have basically the same configuration, although there are some structural differences due to the relationship between the portions where they are used and the members to be connected. I have.

In the drawing, reference numeral 4 denotes a flexible tube. The flexible tube 4 has a spiral tube 5 as a structural body.
Is composed of outer and inner spirals 5a and 5b. The spiral bodies 5a and 5b are formed by spirally winding a metal band such as stainless steel, and thereby the insertion passages of various insertion members are secured inside. In order to provide flexibility in the bending direction, the spirals 5a and 5b are wound with a predetermined pitch interval therebetween, and the winding directions are opposite to each other. On the outer periphery of the spiral tube 5, a tubular mesh body 6 formed by braiding a metal wire is provided. On the tubular mesh body 6, a skin layer 7 is further laminated. here,
The outer skin layer 7 is formed of a soft resin material having good slippage, for example, urethane resin, for keeping the inside of the flexible tube 4 in a sealed state, and for smoothly inserting it into a body cavity or the like.
If the outer skin layer 7 is formed directly on the spiral tube 5, there is a risk that the outer skin layer 7 may be separated from the spiral tube 5 and may be damaged. In order to integrate the outer shell layer 7 and the
Is generally coated with an adhesive.

The flexible tube 4 is formed as described above. If the flexible tube 4 is formed as the flexible tube 1a of the insertion section 1, it must be bent over its entire length. Must. The flexible tube portion 4 bends along an insertion path in a body cavity or the like. Therefore, when an external force acts on the inside of the body cavity, the flexible tube portion 4 must bend flexibly to some extent. However, if the flexibility of the flexible tube portion 1a in the bending direction is made too high, for example, when the resistance at the time of insertion into an insertion path such as a colonoscope or the like is large, the insertion operation may be hindered. is there. Therefore, depending on the insertion path, the flexible tube section 1a must be somewhat hard in the bending direction, that is, the rigidity in the bending direction must be increased. In addition, since the resistance increases as the insertion portion 1 is inserted into the body, the flexibility of the flexible tube portion 1a in the bending direction does not need to be uniform over its entire length, but rather the distal end side is flexible in the bending direction. It is preferable to have such a characteristic that the rigidity increases as it goes to the base end side. Further, an angle part 1b is connected to the flexible tube part 1a,
The angle portion 1b is for directing the distal end hard portion 1c in a desired direction. In some cases, the bending operation is performed to 180 ° or more. For this reason, when the flexible tube 1a is bent at the maximum bending angle or an angle close thereto, stress is not excessively concentrated on the connecting portion between the angle portion 1b and the flexible tube 1a. It is necessary to further increase the flexibility in the vicinity of the connection with the angle portion 1b.

In view of the above demands, the bending characteristics of the flexible tube 4 formed as the flexible tube portion 1a of the insertion portion 1 are as follows.
It is preferable to change the distal end side so as to bend most flexibly and continuously harden at least up to a predetermined position toward the proximal end side. As described above, various measures have been taken to change the hardness of the flexible tube 4 in the bending direction in the axial direction. Since the flexible tube portion 4 includes the spiral bodies 5a and 5b, the tubular mesh tube 6 and the outer skin layer 7, the flexibility in the bending direction is changed based on any of these members. As the helical members 5a and 5b constituting the helical tube 5, those having a configuration in which the width or thickness is continuously changed or the surface is plated to change the thickness of the plating are known. As for the tubular mesh pipe 6, there is a tubular mesh pipe whose knitting method, element wire diameter and the like are changed in the axial direction. Also,
It is also known to change the amount of adhesive supplied to the tubular mesh tube 6. Further, regarding the outer skin layer 7,
Is usually formed by extrusion molding, there is a type in which two kinds of resins having different hardnesses are supplied from an extruder and the mixing ratio is changed in the axial direction. Further, there has been proposed a configuration in which a resin coat layer is formed inside after forming the flexible tube 4 so that the flexibility of the flexible tube portion 4 is changed in the axial direction. .

[0009]

As described above, various devices have been devised to change the characteristics of the flexible tube in the bending direction in the bending direction in the axial direction. This is for imparting crush resistance to the flexible tube portion, and bends almost without resistance in the bending direction. Therefore, depending on the structure of the helical tube, a remarkable difference in hardness cannot be provided. Further, the tubular mesh body is stretchable, and it is not easy to configure the tubular mesh body to have a substantial difference in hardness. Further, the adhesive cannot have stable characteristics over time because it degrades over a long period of time.

The outermost layer has the greatest influence on the bending direction flexibility of the flexible tube. When the flexible tube bends, the outer skin layer contracts at the inner portion in the bending direction and expands at the outer portion. Although the outer skin layer is formed of a soft resin, it is not always elastic, and therefore has a very high resistance to the expansion and contraction. Therefore, the greatest factor in the resistance to bending of the flexible tube is the resistance to expansion and contraction of the outer skin layer. In this sense, changing the hardness of the outer skin layer is extremely advantageous in giving flexibility to the bending direction of the flexible tube. However, extrusion molding using two types of resins having different properties requires a large-scale apparatus. Further, not only is the control of the extrusion pressure of the two types of resins extremely complicated, but also the control becomes complicated. Difficulties arise in that there are significant problems in molding, such as variations in hardness.

The present invention has been made in view of the above points, and an object thereof is to change the flexibility in the bending direction of a flexible tube in the axial direction by a simple processing. Is to do so.

[0012]

In order to achieve the above-mentioned object, a flexible tube of an endoscope according to the present invention may be a flexible tube having a flexible passage having an insertion passage formed therein. In a flexible tube of an endoscope provided with a skin layer made of resin,
The thickness of the outer skin layer in the axial direction is changed by forming a partially thinned portion in the outer skin layer.

As described above, the resistance when the flexible tube bends and the outer skin layer expands and contracts significantly affects the bending characteristics. However, the resistance during expansion and contraction can be changed by the thickness of the outer skin layer. Therefore, by changing the thickness of the outer skin layer, the bending characteristics can be changed in the axial direction. Therefore, the thinned portion is formed on the entire circumference of the outer skin layer or at least one portion thereof, and the thinned portion is thinnest at one end and continuously has a thickness from one end to the other end or an intermediate position. Is preferably increased. In the case where the insertion portion is configured as a flexible tube portion, the end of the thinnest portion on the thinnest side is a connection portion to the angle portion of the insertion portion.

On the other hand, in the method of manufacturing a flexible tube of an endoscope according to the present invention, an extruder is used to form a flexible resin on an outer peripheral surface of a flexible cylindrical body having an insertion passage formed therein. A flexible tube is formed by laminating a skin layer, and then a blade is brought into contact with the skin layer of the flexible tube on the outlet side of the extruder, and the skin layer is scraped to a predetermined depth, and the flexible tube is cut off. By displacing the blade in a direction away from the flexible tube in response to the feed from the extruder, the depth of scraping the outer layer is continuously reduced, and the outer layer is continuously moved in the axial direction. It is characterized in that a thinned portion whose thickness is changed in thickness is formed.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Also in the present invention, since there is substantially no difference in the overall configuration of the endoscope from that shown in FIG. 5, the same reference numerals are used for members that are the same as or equivalent to those shown in FIG.

FIGS. 1 and 2 show the entire structure of the flexible tube. In the figure, reference numeral 10 denotes a flexible tube, and the flexible tube 10 has therein an insertion passage for inserting a soft insertion member such as an optical fiber, a cable, and a tube. The structure of the insertion passage is a helical tube, preferably a double helical tube wound at a predetermined pitch in the opposite direction to each other, and this helical tube is inserted and fitted in a cylindrical mesh. Further, an outer skin layer 11 is laminated on the outer periphery of the tubular mesh body. Although the internal structure is not shown in FIG. 1 and FIG. 2, the laminated structure itself has substantially no difference from the configuration of FIG. 6 described above. The flexible tube 10 is, for example, a flexible tube portion 1a that bends in an arbitrary direction along the insertion path in the insertion section 1.
Is used as a component of In this case, a base 12 for connecting to the angle portion 1b is connected to one end, and a screw ring 13 for screwing to the main body operation unit 2 is connected to the other end. .

Here, the outer skin layer 11 of the flexible tube 10
Does not have a uniform thickness over its entire length. The thinned portion 11a is formed by cutting and flattening a portion indicated by a virtual line in FIG. The thinned portion 11a has the deepest and widest end on the distal end side, that is, the side on which the base 12 connected to the angle portion 1b is mounted, and the screw ring 13 connected to the base end side, that is, the main body operation portion 2. The side on which it is provided has a generally triangular shape that is thin and narrow. Here, when the flexible tube 10 is bent, the outer layer 1 made of a soft resin is formed.
In No. 1, the inner side in the bending direction contracts and the outer side expands. However, when the thickness of the outer skin layer 11 is increased, the resistance to bending increases, and when the thickness is reduced, the resistance to bending decreases. Accordingly, the distal end side of the flexible tube 10 can be easily bent by the reduced thickness, and the thinned portion 1 is formed.
1a is characterized in that the depth and the width are continuously reduced toward the base end side, so that the distal end side of the flexible tube 10 is most easily bent, and becomes harder in the bending direction continuously toward the base end side. Can be provided. When the thickness of the outer skin layer 11 is changed, desired bending characteristics can be provided depending on the degree of the change. However, when the thinned portion 11b is formed, it becomes weaker than other portions. However, if the minimum thickness is suppressed to about half of the normal thickness, sufficient strength is maintained, and there is no risk of breakage or the like. . If the thickness is reduced to half, an extremely large difference in flexibility in the bending direction can be given to other parts.

With the above configuration, for example, when the flexible tube section 1a in the insertion section 1 of the colonoscope is used, the resistance increases as the insertion depth of the insertion section 1 into the body increases. Although it increases, the flexible tube portion 1a, which constitutes the majority of the length of the insertion portion 1, becomes harder in the bending direction as it is inserted deeper into the body, so that the thrust to be pushed into the body can be reliably applied. . Further, since the distal end side is flexibly bent, when the angle portion 1b connected to the flexible tube portion 1a is operated to bend and the angle portion 1b is bent, the connection to the flexible tube portion 1a is performed. It is possible to prevent sharp bends from the set part and to disperse stress,
The durability of the insertion portion 1 is improved, and there is no possibility that an excessive force is applied to the internal insertion member.

On the other hand, the light guide flexible portion 3 is
One end thereof is connected to the main body operation unit 2, and the other end is provided with a connector for detachably connecting to a light source device or the like. Therefore, both ends have a rigid structure. Therefore, it is necessary to change the bending characteristics in the axial direction so that the connecting portion to the rigid structure has rigidity and the intermediate portion bends without resistance. In this case, it is preferable that the thinned portion of the outer skin layer is formed in the middle part of the flexible tube, and that both ends are thickest.

Here, the outer skin layer 11 is formed by molding means using an extruder. Therefore, the thinned portion 11a can be formed in the outer skin layer 11 when performing extrusion molding. Therefore, the thinned portion 11 is added to the outer skin layer 11 together with the extrusion.
A method for forming a will be described with reference to FIG. Note that the thinned portion 11a does not necessarily need to be formed at the time of molding. For example, after the outer skin layer 11 is formed, the thinned portion 11a can be cut off with a cutter or the like as necessary.

FIG. 3 shows an example of the configuration of an extruder for laminating the outer skin layer 11 on the outer periphery of the flexible tube 10. At the stage before the outer skin layer 11 of the flexible tube 10 is laminated, the spiral tube 14 (preferably a double spiral tube)
A flexible tube structure 16 is formed by attaching a tubular net 15 to the flexible tube. In the drawings, reference numeral 20 denotes a molding machine. The molding machine 20 includes a well-known extruding portion 21 composed of a hopper, a screw, and the like, and a synthetic resin in a molten state extruded by the extruding portion 21, for example, a urethane resin. And a head portion 22 for forming a coating on the outer peripheral surface of the flexible tube structure 16.

The head section 22 is configured as a head section called an in-die head, an in-die crosshead, and a solid crosshead. The head section 22 is attached to a head support 23 that supports the head section 22 in a fixed manner. The head support 23 includes a gate 23 a serving as a passage for supplying the synthetic resin 24 in the molten state extruded from the extruding section 21 to the head section 22. The head portion 22 includes a nipple 26 and a die 27 that form a manifold 25 so that the molten resin 24 fed from the gate 23 a can supply the outer skin layer 11 to the outer peripheral surface of the flexible tube structure 16. Structure. The nipple 26 is provided with a conical recess 26 a for guiding the insertion of the flexible tube structure 16. On the right end side of the nipple 26 in the figure, a conical convex portion 26b that forms the manifold 25 in cooperation with the conical concave portion 27a on the left end side of the die 27 is formed.

In the molding machine 20 thus formed, the outer layer 11 formed on the outer periphery of the flexible tube structure 16 is provided at the right side of the die 27 at the outlet of the manifold 25 in FIG. It has an inner peripheral wall 27b to be determined. In the drawing, reference numeral 28 denotes a fastening portion for preventing the nipple 26 and the die 27 from coming off.
7 is locked by a ridge 23b formed on the head support 23 and a ridge 28a formed on the holding cylinder 28 screwed to the head support 23, and a lock nut 29 is screwed on the nipple 26. The molding machine 20 is held in an assembled state.

The molding machine 20 is configured as described above.
The flexible tube constituting body 16 is pushed in the axial direction by pushing means (not shown) to pass through the head portion 22, thereby forming the outer skin layer 11. And this molding machine 20
A blade 30 for forming the thinned portion 11a is provided on the outlet side of the blade. This blade 30 is provided obliquely so that the blade edge faces the molding machine 20 side,
A direction perpendicular to the direction in which the flexible tube 10 as a molded product flows,
That is, it can be moved up and down.

With such a configuration, the flexible tube structure 16 is formed from the side where the base 12 is connected to the molding machine 20.
The blade 30 is lowered to the lowest position immediately after the base 12 passes the position of the blade 30.
Thereby, a part of the outer skin layer 11 is cut and removed. Here, since the resin constituting the outer skin layer 11 is in a state before being cured, the blade 30 can easily penetrate the outer skin layer 11. The position where the blade 30 contacts the outer skin layer 11 is cut deepest. When the blade 30 is lifted in accordance with the feed of the flexible tube 10, the depth and width of the outer skin layer 11 to be cut are continuously reduced, and the blade 30 is separated from the outer skin layer 11. The thinned portion 11a is thus formed. Therefore, the thinned portion 11a having a desired depth and width can be formed by a simple operation that only controls the elevating operation of the blade 30, and the desired flexibility in the bending direction in the axial direction of the flexible tube 10 can be obtained. Characteristic can be provided.

If only one blade 30 is provided, the flexibility in the bending direction will have directionality. For example, if the blade 30 is provided at two or more, preferably about four, at equal angles. Thus, a flexible tube having substantially uniform flexibility in substantially any direction can be formed. The cutting edge of the blade 30 may be linear, but may be formed in an arc shape having a radius of curvature larger than the outer diameter of the flexible tube 10.

Although the thinned portion can be provided over the entire length of the flexible tube as shown in FIGS. 1 and 2, for example,
As in the case of the flexible tube 40 shown in FIG. 4, the thinned portion 41a can be formed from the side where the base 42 is provided on the distal end side of the outer skin layer 41 to the middle position. The thinned portion 41a may be provided not only in one place but also in a large number in the circumferential direction. The flexible tube 40 thus configured
When the base 42 is used as the flexible tube 1a of the insertion portion 1 by connecting the base 42 to the angle portion 1b, the flexible tube 1a is connected to the base end side, that is, the connection side to the main body operation unit 2. In order to improve the insertion operability, a sufficient rigidity in the bending direction is provided, and the distal end portion has no flexible structure, and easily bends following the bending of the angle portion 1b. As a result, the operability of the angle operation is improved, and the stress at the time of bending at a large bending angle such as 180 ° or more can be suppressed from being concentrated on the transition from the flexible tube portion 1a to the angle portion 1b. And the durability of the insertion portion 1 is improved.

When the angle of the angle portion 1b is manipulated, the angle of curvature in the up-down direction is made larger than the degree of curvature in the left-right direction. It is also possible to further reduce the thickness of the thinned portion in the direction of large bending at the distal end side of the flexible tube portion 1a.

[0029]

As described above, according to the present invention, since the thinned portion is formed in a part of the outer layer, the bending direction in the axial direction of the flexible tube can be performed by a simple process of cutting the outer layer. Can have desired characteristics, and can maintain the characteristics very stably, and have a hardness change depending on the thickness of the outer layer, so that the characteristics can be changed over time. There is an effect that there is no possibility of the change.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a flexible tube showing one embodiment of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a cross-sectional view of an extruder for extruding a skin layer together with means for forming a thinned portion.

FIG. 4 is a front view of a flexible tube showing another embodiment of the present invention.

FIG. 5 is an external view showing a general configuration of an endoscope.

FIG. 6 is an explanatory view of a configuration of a flexible tube according to a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Insertion part 1a Flexible tube part 1b Angle part 1c Hard tip part 2 Body operation part 3 Light guide flexible part 10,40 Flexible tube 11,41 Outer skin layer 11a, 41a Thin part 12,42 Base 13 Screw ring 14 Spiral Pipe 15 Cylindrical net body 16 Flexible tube construct 20 Molding machine 21 Extruding part 22 Head part 30 Blade

Claims (4)

[Claims] 1. A flexible tube of an endoscope in which a flexible tubular body having an insertion passage for an insertion member formed therein and having an outer skin layer made of a soft resin is partially thinned in the outer skin layer. A flexible tube for an endoscope, wherein a thickness of the outer skin layer in the axial direction is changed by forming a portion. 2. The thinned portion is formed so that at least a part of the outer skin layer in the circumferential direction has the thinnest one end side and the thickness continuously increases from the one end side to at least a middle position. The flexible tube for an endoscope according to claim 1, wherein: 3. The flexible tube is used as a flexible tube constituting an insertion portion of the endoscope, and the thinnest portion of the thinned portion has an angle of the angle of the flexible tube. The flexible tube of an endoscope according to claim 1, wherein the flexible tube is a connecting part to the part. 4. A flexible tube is formed by laminating an outer skin layer made of a soft resin on an outer peripheral surface of a flexible tubular body having an insertion passage for an insertion member formed therein by an extruder. At the outlet side of the molding machine, a blade is brought into contact with the outer skin layer of the flexible tube, the outer skin layer is scraped to a predetermined depth, and the blade is flexed in accordance with the feeding of the flexible tube from the extruder. By displacing in the direction away from the tube, the depth of shaving the outer skin layer is continuously reduced, and a thinned portion whose thickness changes continuously in the axial direction is formed on this outer skin layer. A method for manufacturing a flexible tube for an endoscope.