Flexible tube for an endoscope

• US 6,860,849 B2
• Filed: 05/04/2001
• Issued: 03/01/2005
• Est. Priority Date: 05/08/2000
• Status: Expired due to Term

• Current Assignee: Hoya Corporation
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: Kasai, Tadashi, Nanba, Hideo, Iwasaka, Kikuo, Matsushita, Minoru
• Primary Examiner(s): Leubecker, John P.
• Application Number:
  US09/848,301
• Publication Number:
  US 20020010386A1
• Time in Patent Office: 1,397 Days
• Field of Search: 600/139, 600/140, 600/121, 604/524, 604/526, 604/527
• US Class Current: 600/140
• CPC Class Codes: A61B 1/00071 Insertion part of the endoscope body A61B1/0055 takes precedence
• CPC Class Codes: A61B 1/005 Flexible endoscopes
• CPC Class Codes: A61L 29/085 Macromolecular materials
• CPC Class Codes: A61L 29/12 Composite materials, i.e. containing one material dispersed in a matrix of the same or different material
• CPC Class Codes: B32B 1/08 Tubular products
• CPC Class Codes: B32B 2307/51 Elastic
• CPC Class Codes: B32B 2597/00 Tubular articles, e.g. hoses, pipes
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 27/40 comprising polyurethanes
• CPC Class Codes: B32B 3/10 characterised by a discontinuous layer, i.e. formed of separate pieces of material
• CPC Class Codes: B32B 3/30 characterised by a layer formed with recesses or projections, e.g. hollows, grooves, protuberances, ribs apertured layer B32B3/266; layer with cavities or internal voids B32B3/26
• CPC Class Codes: B32B 7/022 Mechanical properties
• CPC Class Codes: C08L 23/00 Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 25/06 Polystyrene
• CPC Class Codes: C08L 27/12 containing fluorine atoms
• CPC Class Codes: C08L 67/00 Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain of polyester-amides C08L77/12; of polyester-imides C08L79/08; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 75/04 Polyurethanes

Abstract

A flexible tube for an endoscope has an elongated tubular core body, and an outer cover which is provided over the core body. The outer cover is composed of an inner layer, an outer layer and at least one intermediate layer. In this flexible tube, any one of the layers is different from one of the other layers in its property. Further, at least one of the layers has a thickness-varying region where the thickness of the layer varies in its longitudinal direction. In addition, the inner layer of the outer cover has projections which are integrally formed on the inner layer so that the projections project into holes and/or the recesses formed on the core body. This structure makes it possible to produce a flexible tube for an endoscope that has high durability, high flexibility and high chemical resistance as well as excellent operationability.

Claims

1. A flexible tube for an endoscope, comprising:

an elongated tubular core body; and

an outer cover which is provided over the core body, the outer cover having a portion which is formed into a laminate structure composed of at least three layers, the layers of the laminate structure including an inner layer, an outer layer and at least one intermediate layer formed between the inner layer and the outer layer, wherein the intermediate layer of the outer cover has a higher elasticity than the inner and outer layers so that the intermediate layer functions as cushioning between the inner layer and the outer layer.

2. The flexible tube as claimed in claim 1, wherein the core body has a plurality of holes and/or a plurality of recesses.

3. The flexible tube as claimed in claim 2, wherein the inner layer of the outer cover has projections which are integrally formed on the inner layer so that the projections project into the holes and/or the recesses.

4. The flexible tube as claimed in claim 1, wherein the portion of the laminate structure of the outer cover has a substantially uniform thickness over its entire region.

5. The flexible tube as claimed in claim 1, wherein any one of the inner, outer and intermediate layers is different from one of the other layers in its physical property and/or chemical property.

6. The flexible tube as claimed in claim 5, wherein any one of the inner, outer and intermediate layers is different from one of the other layers in its hardness.

7. The flexible tube as claimed in claim 1, wherein the outer layer of the outer cover contains a material having resistance to a chemical.

8. The flexible tube as claimed in claim 1, wherein the intermediate layer of the outer cover is formed of a material having higher elasticity than that of the outer layer.

9. The flexible tube as claimed in claim 1, wherein the outer layer of the outer cover is formed of a material having higher hardness than that of the inner layer or the intermediate layer.

10. The flexible tube as claimed in claim 1, wherein at least a part of the outer layer of the outer cover has higher hardness than that of the inner layer or the intermediate layer.

11. The flexible tube as claimed in claim 1, wherein at least one of the inner, outer and intermediate layers of the outer cover is formed of a material that contains at least one selected from the group consisting of polyurethane-based elastomer, polyester-based elastomer, polyolefine-based elastomer, polystyrene-based elastomer, polyamide-based elastomer, fluorine-based elastomer, and fluororubber.

12. The flexible tube as claimed in claim 1, wherein each of the inner, outer and intermediate layers of the outer cover is formed of a material that contains at least one selected from the group consisting of polyurethane-based elastomer, polyester-based elastomer, polyolefine-based elastomer, polystyrene-based elastomer, polyamide-based elastomer, fluorine-based elastomer, and fluororubber.

13. The flexible tube as claimed in claim 1, wherein the outer cover is provided over the core body through an extrusion molding process.

14. The flexible tube as claimed in claim 1, wherein the flexible tube has tip and base ends, and flexibility of the flexible tube increases in a gradual or stepwise manner along the direction from the base end toward the tip end.

15. The flexible tube as claimed in claim 1, wherein any one of the layers constituting the portion of the laminate structure of the outer cover is different from one of the other layers in its physical property and/or chemical property.

16. The flexible tube as claimed in claim 15, wherein any one of layers constituting the laminate structure of the outer cover is different from one of the other layers in hardness.

17. A flexible tube for an endoscope, comprising:

an elongated tubular core body; and

an outer cover which is provided over the core body, the outer cover having a portion which is formed into a laminate structure composed of at least three layers, the layers of the laminate structure including an inner layer, an outer layer and at least one intermediate layer formed between the inner layer and the outer layer, wherein the intermediate layer of the outer cover has a higher elasticity than the inner and outer layers so that the intermediate layer functions as cushioning between the inner layer and the outer layer;

wherein the core body has a plurality of holes and/or a plurality of recesses; and

wherein the core body includes;

a coil that is formed by winding a band-shaped material into a spiral form; and

a reticular tube that is formed by weaving a plurality of fine wires together, the reticular tube being provided over the coil.

18. The flexible tube as claimed in claim 17, wherein at least one of the fine wires forming the reticular tube is coated with a synthetic resin so that a coating of the synthetic resin is provided on the fine wire, in which at least a part of the coating is fused with and bonded to the inner layer of the outer cover.

19. The flexible tube as claimed in claim 18, wherein the inner layer of the outer cover contains a material having a compatibility with the synthetic resin of the coating.