Flexible tube for an endoscope and electronic endoscope equipped with the flexible tube

• US 20020028984A1
• Filed: 08/31/2001
• Published: 03/07/2002
• Est. Priority Date: 09/01/2000
• Status: Active Grant

• Current Assignee: Hoya Corporation
• Original Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha Tokyo Japan
• Inventors: Sugiyama, Akira, Kasai, Tadashi, Hayakawa, Shinji, Takeshige, Masaru
• Granted Patent: US 6,623,424 B2
• Time in Patent Office: Days
• US Class Current: 600/139
• CPC Class Codes: A61B 1/00071 Insertion part of the endoscope body A61B1/0055 takes precedence
• CPC Class Codes: A61B 1/00078 with stiffening means
• CPC Class Codes: A61B 1/00135 Oversleeves mounted on the endoscope prior to insertion
• CPC Class Codes: A61B 1/005 Flexible endoscopes

Abstract

A flexible tube for an endoscope which has excellent insertion operability is disclosed. The flexible tube includes and an elongated flexible tubular body constructed from a core body having a hollow space and an outer cover which is provided over the outer periphery of the core body and formed into a laminated structure having a plurality of layers. The tubular body is formed with a plurality of easily bendable portions which are provided in a spaced apart manner along the longitudinal direction thereof, each of these easily bendable portion being adapted to bend locally with a smaller curvature radius when the flexible tube is bent in one direction. The average interval between the adjacent easily bendable portions is preferably in the range 50-400 mm. The easily bendable portions is formed by locally changing the flexural rigidity of the outer cover. For example, it is formed by changing the thickness of at least one layer of the laminated structure of the outer cover at a position corresponding to the easily bendable portion.

Claims

1. A flexible tube for an endoscope, comprising:

an elongated flexible tubular body; and

a plurality of easily bendable portions provided in the tubular body in a spaced apart manner along the longitudinal direction thereof, each of these easily bendable portion being adapted to be bent locally with a smaller curvature radius when the flexible tube is bent in one direction.

2. The flexible tube for an endoscope as claimed in claim 1, wherein the average interval between the adjacent easily bendable portions is in the range 50-400 mm.

3. The flexible tube for an endoscope as claimed in claim 1, wherein when the average of the curvature radius of each of said easily bendable portions is defined as R₁ and the curvature radius of the center portion lying between said adjacent easily bendable portions is defined as R₂, the value of the ratio R₁/R₂ in the bending state lies in the range of 0.2-0.9.

4. The flexible tube for an endoscope as claimed in claim 1, wherein the flexible tubular body includes a core body having a hollow space and an outer cover which is provided over the outer periphery of the core body, the outer cover being formed into either of a single layer structure or a laminated structure having a plurality of layers.

5. The flexible tube for an endoscope as claimed in claim 4, wherein each of said easily bendable portions is formed by locally changing the flexural rigidity of the outer cover.

6. The flexible tube for an endoscope as claimed in claim 4, wherein at least one of said easily bendable portions is formed by changing the thickness of at least one layer of the laminated structure of the outer cover at a position corresponding to the easily bendable portion.

7. The flexible tube for an endoscope as claimed in claim 4, wherein at least one of said easily bendable portions is constructed from a portion of the outer cover where the thickness of the outer cover changes along the circumferential direction.

8. The flexible tube for an endoscope as claimed in claim 4, wherein the outer cover has a portion which is made of a material including at least one kind of material selected from the group consisting of polyurethane-based elastomer, polyester-based elastomer, polyolefin-based elastomer, polystyrene-based elastomer, polyamide-based elastomer, and fluoro-based elastomer.

9. The flexible tube for an endoscope as claimed in claim 4, wherein the outer cover is applied over the core body using an extrusion molding method.

10. The flexible tube for an endoscope as claimed in claim 4, wherein the core body includes a coil formed by winding a band-shaped material into a spiral and a braided tube provided over the outer periphery of the coil and formed by braiding fine wires.

11. The flexible tube for an endoscope as claimed in claim 4, wherein at least one of said easily bendable portions is formed by forming the outer cover so as to have an elliptical cross section at a position corresponding to the easily bendable portion.

12. The flexible tube for an endoscope as claimed in claim 4, wherein at least one of said easily bendable portions is formed by increasing the winding pitch of the coil locally at a position corresponding to the easily bendable portion.

13. The flexible tube for an endoscope as claimed in claim 4, wherein at least one of said easily bendable portions is formed by reducing the width and/or thickness of the band-shaped material of the coil 21 locally at a position corresponding to the easily bendable portion.

14. An electronic endoscope, comprising:

an operation section which is operated by an operator; and

a flexible tube for an endoscope which is connected to the operation section, the flexible tube including an elongated flexible tubular body and a plurality of easily bendable portions provided in the tubular body in a spaced apart manner along the longitudinal direction thereof, each of these easily bendable portion being adapted to bend locally with a smaller curvature radius when the flexible tube is bent in one direction.