Flexible tube for endoscope

• US 4,899,787 A
• Filed: 06/16/1987
• Issued: 02/13/1990
• Est. Priority Date: 11/17/1981
• Status: Expired due to Term

• Current Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Original Assignee: Kabushiki Kaisha Medos Kenkyusho
• Inventors: Ouchi, Teruo, Shibuya, Hiromichi
• Primary Examiner(s): Jillions, John M.
• Application Number:
  US07/062,451
• Time in Patent Office: 973 Days
• Field of Search: 138/130-132, 138/125, 138/129, 138/144, 128/4, 128/6, 128/343, 128/348.1, 604/280, 604/282
• US Class Current: 138/131
• CPC Class Codes: A61B 1/0055 Constructional details of insertion parts, e.g. vertebral elements
• CPC Class Codes: A61M 25/0012 with embedded structures, e.g. coils, braids, meshes, strands or radiopaque coils
• CPC Class Codes: B29C 63/18 using tubular layers or sheathings B29C63/26 and B29C63/38 take precedence; placing tubular labels around rigid containers B65C3/065
• CPC Class Codes: B29L 2023/007 Medical tubes other than catheters catheters B29L2031/7542

Abstract

A flexible tube for use in an endoscope comprises a flexible basic tubular core structure including an outer meshwork tube, and a thermoplastic synthetic resin tube bonded to the outer meshwork tube of the tubular core structure in a manner such that the resin tube maintains an inherent compressive pre-stress in the finished flexible tube. An endoscope tube having flexibility which varies in a step-wise manner from one end of the tube to the other is obtained by integrally bonding two or more thermoplastic synthetic resin tube sections formed of respective resin materials having different hardnesses to the outer surface of the tubular core structure to form a coating layer in an analogous manner. The ends of adjacent tube sections substantially abut each other and upon heating the tube sections to a temperature only slightly higher than a softening point but lower than a melting point of any one of them, the localized regions of the respective pairs of abutting tube section ends are heated to a temperature which is as close as possible to a melting point of one of the tube sections having a higher melting point than that of the other tube section, whereby the end of the other tube section having a lower melting point is fused with the end of the adjacent tube section, and after cooling of the tube sections, a continuous and integral tube is obtained without any joints or junctures.

Claims

1. A flexible tube for use in an endoscope, comprising:

a flexible basic tubular core structure including an inner metallic tubular spiral having a series of turns spaced from each other by gaps and an outer surface constituted by an outer meshwork tube formed of a fabric mesh constituted by mesh elements, said outer meshwork tube being situated tightly over said inner metallic tubular spiral; and

at least one thermoplastic synthetic resin tube bonded to the meshwork of said meshwork tube, said synthetic resin tube having an inner diameter prior to being located over said tubular core structure which is less than an outer diameter of said basic tubular core structure, said bonding being accomplished by,

(a) expanding the inner diameter of said synthetic resin tube and locating the same over said meshwork tube of said tubular core structure;

(b) allowing said tube to contract so that said tube exerts a compressive force on said core structure;

(c) heating said synthetic resin tube to a temperature at least slightly higher than a softening point and below a melting point of the synthetic resin of said tube so that the resin softens and enters into the meshwork tube under the compressive force;

(d) cooling said synthetic resin tube so that the resin hardens and is integrally bonded to the meshwork of said meshwork tube while retaining an inherent compressive prestress in the flexible tube so formed;

said flexible tube so formed having a construction wherein;

(a) said synthetic resin tube has portions which curve at least partially into spaces between said mesh elements of said outer meshwork tube, so that said resin tube is tightly bonded to said meshwork tube;

(b) said resin of said synthetic resin tube is totally absent from said gaps between said turns of said metallic tubular spiral; and

(c) said synthetic resin tube has an inherent compressive pre-stress acting inwardly on said tubular core structure.

2. A flexible tube for endoscopes as recited in claim 1 wherein said flexible basic tubular core structure comprises a multilayered structure including a clockwise extending metallic tubular spiral and a counter-clockwise extending metallic tubular spiral.

3. A flexible tube for endoscopes, comprising:

a flexible basic tubular core structure having a multilayered construction and including a first metallic tubular spiral having a series of turns spaced from each other by gaps, a first meshwork tube formed of a fabric mesh constituted by mesh elements, said first meshwork tube being situated tightly over said first metallic tubular spiral, a second metallic tubular spiral having a series of turns spaced from each other by gaps and situated over said first meshwork tube, a second meshwork tube formed of a fabric mesh constituted by mesh elements and being situated tightly over said second metallic tubular spiral; and

at least one thermoplastic synthetic resin tube bonded to the meshwork of said second meshwork tube, said synthetic resin tube having an inner diameter prior to being located over said tubular core structure which is less than an outer diameter of said basic tubular core structure, said bonding being accomplished by,

(a) expanding the inner diameter of said synthetic resin tube and locating the same over said second meshwork tube of said tubular core structure;

(b) allowing said tube to contract so that said tube exerts a compressive force on said core structure;

(c) heating said synthetic resin tube to a temperature at least slightly higher than a softening point and below a melting point of the synthetic resin of said tube so that the resin softens and enters into the second meshwork tube under the compressive force;

(d) cooling said synthetic resin tube so that the resin hardens and is integrally bonded to the meshwork of said second meshwork tube while retaining an inherent compressive pre-stress in the flexible tube so formed;

said flexible tube so formed having a construction wherein;

(a) said synthetic resin tube has portions which curve at least partially into spaces between said mesh elements of said second meshwork tube, so that said resin tube is tightly bonded to said second meshwork tube;

(b) said resin of said synthetic resin tube is totally absent from said gaps between said turns of said second metallic tubular spiral; and

(c) said synthetic resin tube has an inherent compressive pre-stress acting inwardly on said tubular core structure.

4. A flexible tube for use in an endoscope, comprising:

a flexible basic tubular core structure including an inner metallic tubular spiral having a series of turns spaced from each other by gaps and an outer surface constituted by an outer meshwork tube formed of a fabric mesh constituted by mesh elements, said outer meshwork tube being situated tightly over said inner tubular spiral; and

at least two thermoplastic synthetic resin tube sections respectively formed of resin materials having different hardnesses bonded as a whole to the network of said meshwork tube, said synthetic resin tube sections having inner diameters prior to their being located over said tubular core structure which are less than an outer diameter of said basic tubular core structure, said bonding being accomplished by,

(a) expanding the inner diameter of said synthetic resin tube sections and locating the same over said meshwork tube of said tubular core structure so that respective adjacent ends of adjacent tube sections abut each other;

(b) allowing said tube sections to contract so that said tube sections exert a compressive force on said core structure;

(c) heating said synthetic resin tube sections to a temperature at least slightly higher than a softening point and below a melting point of said synthetic resin of said tube so that the resin softens and enters into the meshwork of said meshwork tube under the compressive force;

(d) heating only the regions of said abutting ends of said resin tube sections substantially to a melting point of the tube sections to fuse the respective abutting ends to each other;

(e) cooling said synthetic resin tube sections so that the resin hardens and is integrally bonded to the meshwork of said meshwork tube while retaining an inherent compressive pre-stress in the flexible tube so formed, said flexible tube so formed having a construction wherein

(a) said synthetic resin tube sections have portions which curve at least partially into spaces between said mesh elements of said outer meshwork tube, so that said resin tube sections are tightly bonded to said meshwork tube;

(b) said resin of said synthetic resin tube sections is totally absent from said gaps between said turns of said metallic tubular spiral; and

(c) said synthetic resin tube sections have an inherent compressive pre-stress acting inwardly on said tubular core structure,

whereby the flexible tube has a flexibility which varies from one end of the tube to the other.

5. A flexible tube for endoscopes as recited in claim 4 wherein said flexible basic tubular core structure comprises a multi-layered structure including a clockwise extending metallic tubular spiral and a counter-clockwise extending metallic tubular spiral.

6. A flexible tube for endoscopes, comprising:

a flexible basic tubular core structure having a multilayered construction and including a first metallic tubular spiral having a series of turns spaced from each other by gaps, a first meshwork tube formed of a fabric mesh constituted by mesh elements, said first meshwork tube being situated tightly over said first tubular spiral, a second metallic tubular spiral having a series of turns spaced from each other by gaps and situated over said first meshwork tube, a second meshwork tube formed of a fabric mesh constitued by mesh elements and being situated tightly over said second metallic tubular spiral; and

at least two thermoplastic synthetic resin tube sections respectively formed of resin materials having different hardnesses bonded as a whole to the meshwork of said second meshwork tube, said synthetic resin tube sections having inner diameters prior to being located over said tubular core structure which are less than an outer diameter of said basic tubular core structure, said bonding being accomplished by,

(a) expanding the inner diameter of said synthetic resin tube sections and locating the same over said second meshwork tube of said tubular core structure so that respective adjacent ends of adjacent tube sections abut each other;

(b) allowing said tube sections to contract so that said tube sections exert a compressive force on said core structure;

(c) heating said synthetic resin tube sections to a temperature at least slightly higher than a softening point and below a melting point of said synthetic resin of said tube so that the resin softens and enters into the meshwork of said second meshwork tube under the compressive force;

(d) heating only the regions of said abutting ends of said resin tube sections substantially to a melting point of the tube sections to fuse the respective abutting ends to each other;

(e) cooling said synthetic resin tube sections so that the resin hardens and is integrally bonded to the meshwork of said second meshwork tube while retaining an inherent compressive pre-stress in the flexible tube so formed;

said flexible tube so formed having a construction wherein

(a) said synthetic resin tube sections have portions which curve at least partially into spaces between said mesh elements of said second meshwork tube, so that said resin tube sections are tightly bonded to said second meshwork tube;

(b) said resin of said synthetic resin tube sections is totally absent from said gaps between said turns of said second metallic tubular spiral; and

(c) said synthetic resin tube sections have an inherent compressive pre-stress acting inwardly on said tubular core structure,

whereby the flexible tube has a flexibility which varies from one end of the tube to the other.

7. A flexible tube for endoscopes, comprising:

a flexible basic tubular core structure having a multilayered construction and including a first metallic tubular spiral having a series of turns spaced from each other by gaps, a first meshwork tube formed of a fabric mesh constituted by mesh elements, said first meshwork tube being situated tightly over said first metallic tubular spiral, a second metallic tubular spiral having a series of turns spaced from each other by gaps and situated over said first meshwork tube, a second meshwork tube formed of a fabric mesh constituted by mesh elements and being situated tightly over said second metallic tubular spiral; and

at least one thermoplastic synthetic resin tube bonded to the meshwork of said second meshwork tube, said synthetic resin tube having an inner diameter prior to being located over said tubular core structure which is less than an outer diameter of said basic tubular core structure, said bonding being accomplished by,

(a) expanding the inner diameter of said synthetic resin tube and locating the same over said second meshwork tube of said tubular core structure;

(b) allowing said tube to contract so that said tube exerts a compressive force on said core structure;

(c) heating said synthetic resin tube to a temperature at least slightly higher than a softening point and below a melting point of the synthetic resin of said tube so that the resin softens and enters into the second meshwork tube under the compressive force;

(d) cooling said synthetic resin tube so that the resin hardens and is integrally bonded to the meshwork of said second meshwork tube while retaining an inherent compressive pre-stress in the flexible tube so formed;

said flexible tube so formed having a construction wherein;

(a) said synthetic resin tube has regions wherein said mesh elements of said second meshwork tube are embedded therein, so that said resin tube is tightly bonded to said second meshwork tube;

(b) said resin of said synthetic resin tube is totally absent from said gaps between said turns of said second metallic tubular spiral; and

(c) said synthetic resin tube has an inherent compressive pre-stress acting inwardly on said tubular core structure.

8. A flexible tube for endoscopes, comprising:

a flexible basic tubular core structure having a multi-layered construction and including a first metallic tubular spiral having a series of turns spaced from each other by gaps, a first meshwork tube formed of a fabric mesh constituted by mesh elements, said first meshwork tube being situated tightly over said first tubular spiral,

a second metallic tubular spiral having a series of turns spaced from each other by gaps and situated over said first meshwork tube, a second meshwork tube formed of a fabric mesh constituted by mesh elements and being situated tightly over said second metallic tubular spiral; and

at least two thermoplastic synthetic resin tube sections respectively formed of resin materials having different hardnesses bonded as a whole to the meshwork of said second meshwork tube, said synthetic resin tube sections having inner diameters prior to being located over said tubular core structure which are less than an outer diameter of said basic tubular core structure, said bonding being accomplished by,

(a) expanding the inner diameter of said synthetic resin tube sections and locating the same over said second meshwork tube of said tubular core structure so that respective adjacent ends of adjacent tube sections abut each other;

(b) allowing said tube sections to contract so that said tube sections exert a compressive force on said core structure;

(c) heating said synthetic resin tube sections to a temperature at least slightly higher than a softening point and below a melting point of said synthetic resin of said tube so that the resin softens and enters into the meshwork of said second meshwork tube under the compressive force;

(d) heating only the regions of said abutting ends of said resin tube sections substantially to a melting point of the tube sections to fuse the respective abutting ends to each other;

(e) cooling said synthetic resin tube sections so that the resin hardens and is integrally bonded to the meshwork of said second meshwork tube while retaining an inherent compressive pre-stress in the flexible tube so formed;

said flexible tube so formed having a construction wherein

(a) said synthetic resin tube sections have regions wherein said mesh elements of said second meshwork tube are embedded therein, so that said resin tube sections are tightly bonded to said second meshwork tube;

(b) said resin of said synthetic resin tube sections is totally absent from said gaps between said turns of said second metallic tubular spiral; and

(c) said synthetic resin tube sections have an inherent compressive pre-stress acting inwardly on said tubular core structure,

whereby the flexible tube has a flexibility which varies from one end of the tube to the other.

9. A flexible tube for use in an endoscope, comprising:

a flexible basic tubular core structure including an inner metallic tubular spiral having a series of turns spaced from each other by gaps and an outer surface constituted by an outer meshwork tube formed of a fabric mesh constituted by mesh elements, said outer meshwork tube being situated tightly over said inner metallic tubular spiral; and

at least one thermoplastic synthetic resin tube bonded to the meshwork of said meshwork tube, said synthetic resin tube having an inner diameter prior to being located over said tubular core structure which is less than an outer diameter of said basic tubular core structure, said bonding being accomplished by,

(a) expanding the inner diameter of said synthetic resin tube and locating the same over said second meshwork tube of said tubular core structure;

(b) allowing said tube to contract so that said tube exerts a compressive force on said core structure;

(c) heating said synthetic resin tube to a temperature at least slightly higher than a softening point and below a melting point of the synthetic resin of said tube so that the resin softens and enters into the meshwork tube under the compressive force;

(d) cooling said synthetic resin tube so that the resin gardens and is integrally bonded to the meshwork of said meshwork tube while retaining an inherent compressive pre-stress in the flexible tube so formed;

said flexible tube so formed having a construction wherein;

(a) said synthetic resin tube has regions wherein said mesh elements of said outer meshwork tube are embedded therein, so that said resin tube is tightly bonded to said meshwork tube;

(b) said resin of said synthetic resin tube is totally absent from said gaps between said turns of said second metallic tubular spiral; and

(c) said synthetic resin tube has an inherent compressive pre-stress acting inwardly on said tubular core structure.

10. A flexible tube for endoscopes as recited in claim 9 wherein said flexible basic tubular core structure comprises a multilayered structure including a clockwise extending metallic tubular spiral and a counter-clockwise extending metallic tubular spiral.

11. A flexible tube for use in an endoscope, comprising:

a flexible basic tubular core structure including an inner metallic tubular spiral having a series of turns spaced from each other by gaps and an outer surface constituted by an outer meshwork tube formed of a fabric mesh constituted by mesh elements, said outer meshwork tube being situated tightly over said inner tubular spiral; and

at least two thermoplastic synthetic resin tube sections respectively formed of resin materials having different hardnesses bonded as a whole to the meshwork of said meshwork tube, said synthetic resin tube sections having inner diameters prior to their being located over said tubular core structure which is less than an outer diameter of said basic tubular core structure, said bonding being accomplished by,

(a) expanding the inner diameter of said synthetic resin tube sections and locating the same over said second meshwork tube of said tubular core structure so that respective adjacent ends of adjacent tube sections abut each other;

(b) allowing said tube sections to contract so that said tube sections exert a compressive force on said core structure;

(c) heating said synthetic resin tube sections to a temperature at least slightly higher than a softening point and below a melting point of the synthetic resin of said tube so that the resin softens and enters into the meshwork of said meshwork tube under the compressive force;

(d) heating only the regions of said abutting ends of said resin tube sections substantially to a melting point of the tube sections to fuse the respective abutting ends to each other;

(e) cooling said synthetic resin tube sections so that the resin hardens and is integrally bonded to the meshwork of said meshwork tube while retaining an inherent compressive pre-stress in the flexible tube so formed, said flexible tube so formed having a construction wherein

(a) said synthetic resin tube section have regions wherein said mesh elements of said meshwork tube are embedded therein, so that said resin tube sections are tightly bonded to said meshwork tube;

(b) said resin of said synthetic resin tube sections is totally absent from said gaps between said turns of said metallic tubular spiral; and

(c) said synthetic resin tube sections have an inherent compressive pre-stress acting inwardly on said tubular core structure,

whereby the flexible tube has a flexibility which varies from one end of the tube to the other.

12. A flexible tube for endoscopes as recited in claim 11, wherein said flexible basic tubular core structure comprises a multilayered structure including a clockwise extending metallic tubular spiral and a counter-clockwise extending metallic tubular spiral.