Flexible tube for an endoscope

• US 5,788,714 A
• Filed: 08/07/1996
• Issued: 08/04/1998
• Est. Priority Date: 08/14/1995
• Status: Expired due to Term

• Current Assignee: Hoya Corporation
• Original Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Inventors: Ouchi, Teruo
• Primary Examiner(s): FLANAGAN, BEVERLY MEINDL
• Application Number:
  US08/694,499
• Time in Patent Office: 727 Days
• Field of Search: 600/139, 600/140, 600/142, 600/143, 600/144, 600/920, 138/118, 138/123, 138/124, 138/127
• 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 1/0011 Manufacturing of endoscope parts
• CPC Class Codes: A61B 1/0055 Constructional details of insertion parts, e.g. vertebral elements
• CPC Class Codes: A61M 25/0045 multi-layered, e.g. coated coating materials A61L29/08
• CPC Class Codes: A61M 25/005 with embedded materials for reinforcement, e.g. wires, coils, braids
• CPC Class Codes: B32B 1/08 Tubular products
• CPC Class Codes: B32B 15/02 Layer formed of wires, e.g. mesh
• CPC Class Codes: B32B 15/095 comprising polyurethanes
• CPC Class Codes: B32B 15/18 comprising iron or steel B32B15/011, B32B15/012 and B32B15/013 take precedence
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2255/02 on fibrous or filamentary layer
• CPC Class Codes: B32B 2255/06 on metal layer
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2262/0261 Polyamide fibres
• CPC Class Codes: B32B 2262/0276 Polyester fibres
• CPC Class Codes: B32B 2262/103 Metal fibres
• CPC Class Codes: B32B 2262/106 Carbon fibres, e.g. graphite fibres
• CPC Class Codes: B32B 2274/00 Thermoplastic elastomer material
• CPC Class Codes: B32B 2307/7376 Thickness
• CPC Class Codes: B32B 25/10 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 2597/00 : Tubular articles, e.g. hoses, pipes
• CPC Class Codes: B32B 27/40 : comprising polyurethanes
• CPC Class Codes: B32B 5/024 : Woven fabric
• CPC Class Codes: D04C 1/06 : Braid or lace serving particular purposes
• CPC Class Codes: G02B 23/2476 : Non-optical details, e.g. housings, mountings, supports

Abstract

A flexible tube for an endoscope that includes a spiral tube, a netted tube that covers the outer surface of the spiral tube, and a jacket. The netted tube is formed by braiding a plurality of strand bundles each formed by closely arranging a plurality of fine wires in parallel. The jacket is made of a flexible synthetic resin which covers the outer surface of the netted tube. The braid density K of the netted tube lies in a range of 0.772≦K≦0.906.

Claims

1. A flexible tube for an endoscope, comprising:

a spiral tube;

a netted tube covering an outer surface of said spiral tube, said netted tube being formed by braiding a plurality of strand bundles each formed by closely arranging a plurality of fine wires in parallel; and

a jacket made of a flexible synthetic resin which covers an outer surface of said netted tube;

wherein a braid density K of said netted tube lies in a range of 0.772≦

K≦

0.906;

wherein K=(S-s)/S;

wherein "S" is an area of an intersection of two strand bundles in union with an area of a gap between said intersecting strand bundles and neighboring strand bundles of one side of said intersecting strand bundles, the widths of said area "S" being substantially equal; and

wherein "s" is the area of the gap produced by the intersecting strand bundles, wherein no strands are covered, the widths of said area "s" being substantially equal.

2. The flexible tube according to claim 1, wherein said jacket is formed by dissolving a synthetic resin in a solvent and applying a resultant material to said outer surface of said netted tube.

3. The flexible tube according to claim 1, wherein said jacket is formed by heating a thermoplastic synthetic resin at a temperature higher than a softening point of said thermoplastic synthetic resin, so that said thermoplastic synthetic resin penetrates gaps formed in said netted tube from outside said netted tube.

4. The flexible tube according to claim 1, wherein said jacket comprises a synthetic resin consisting of a polyurethane elastomer.

5. The flexible tube according to claim 1, wherein said jacket is formed by firstly covering said netted tube with a synthetic resin formed in a tubular shape, and secondly by heating said synthetic resin at a temperature higher than a softening point of said synthetic resin, so that said synthetic resin penetrates gaps formed in said netted tube from outside said netted tube.

6. The flexible tube according to claim 1, wherein said plurality of fine wires are each made of metal.

7. The flexible tube according to claim 6, wherein said plurality of fine wires are each made of a stainless steel.

8. The flexible tube according to claim 6, wherein said plurality of fine wires are each made of a copper alloy.

9. The flexible tube according to claim 6, wherein said plurality of fine wires are each made of a tungsten steel.

10. The flexible tube according to claim 1, wherein the following relationships are satisfied:

space="preserve" listing-type="equation">45°

≦

α

≦

65°

,

and

space="preserve" listing-type="equation">n=24,

wherein "α

" represents a braid angle and "n" represents a number of strands contained in one of said plurality of strand bundles,

and further wherein said number "n" satisfies all the following relationships;

2.89 D≦

n≦

6.41 D when dw is equal to 0.02 mm,

1.93 D≦

n≦

4.27 D when dw is equal to 0.03 mm,

12. The flexible tube according to claim 10, wherein a maximum value of said average diameter "D" satisfies all the following relationships:

1.9 mm≦

D≦

4.1 mm when dw is equal to 0.02 mm,

2.9 mm≦

D≦

6.2 mm when dw is equal to 0.03 mm,

3.8 mm≦

D≦

8.2 mm when dw is equal to 0.04 mm,

4.7 mm≦

D≦

10.3 mm when dw is equal to 0.05 mm,

5.7 mm≦

D≦

12.3 mm when dw is equal to 0.06 mm,

6.6 mm≦

D≦

14.4 mm when dw is equal to 0.07 mm,

7.5 mm≦

D≦

16.4 mm when dw is equal to 0.08 mm,

8.5 mm≦

D≦

18.4 mm when dw is equal to 0.09 mm,

9.4 mm≦

D≦

20.6 mm when dw is equal to 0.10 mm, and

11.4 mm≦

D≦

24.4 mm when dw is equal to 0.12 mm.

13. The flexible tube according to claim 10, wherein said plurality of fine wires are each made of metal.

14. The flexible tube according to claim 12, wherein said plurality of fine wires are each made of a stainless steel.

15. The flexible tube according to claim 12, wherein said plurality of fine wires are each made of a copper alloy.

16. The flexible tube according to claim 12, wherein said plurality of fine wires are each made of a tungsten steel.

17. The flexible tube according to claim 10, wherein said plurality of fine wires comprise metal fine wires and non-metal fine wires.

18. The flexible tube according to claim 16, wherein said non-metal fine wires are made of polyester fibers.

19. The flexible tube according to claim 16, wherein said non-metal fine wires are made of nylon fibers.

20. The flexible tube according to claim 16, wherein said non-metal fine wires are made of carbon fibers.

21. The flexible tube according to claim 1, wherein the following relationships are satisfied:

space="preserve" listing-type="equation">45°

≦

α

≦

65°

,

and

space="preserve" listing-type="equation">n=32,

wherein "α

" represents a braid angle and "n" represents a number of strands contained in one of said plurality of strand bundles,

and further wherein said number "n" satisfies all the following relationships;

2.17 D≦

n≦

4.81 D when dw is equal to 0.02 mm,

1.45 D≦

n≦

3.20 D when dw is equal to 0.03 mm,

1.09 D≦

n≦

2.40 D when dw is equal to 0.04 mm,

0.87 D≦

n≦

1.92 D when dw is equal to 0.05 mm,

0.73 D≦

n≦

1.60 D when dw is equal to 0.06 mm,

0.62 D≦

n≦

1.37 D when dw is equal to 0.07 mm,

0.55 D≦

n≦

1.20 D when dw is equal to 0.08 mm,

0.49 D≦

n≦

1.06 D when dw is equal to 0.09 mm,

0.44 D≦

n≦

0.96 D when dw is equal to 0.10 mm, and

0.37 D≦

n≦

0.80 D when dw is equal to 0.12 mm,

wherein "dw" represents a diameter of a strand of each strand bundle in said plurality of strand bundles and "D" represents an average diameter of said netted tube.

22. The flexible tube according to claim 20, wherein a maximum value of said average diameter "D" satisfies all the following relationships:

2.5 mm≦

D≦

5.5 mm when dw is equal to 0.02 mm,

3.8 mm≦

D≦

8.2 mm when dw is equal to 0.03 mm,

5.0 mm≦

D≦

11.0 mm when dw is equal to 0.04 mm,

6.3 mm≦

D≦

13.7 mm when dw is equal to 0.05 mm,

7.5 mm≦

D≦

16.4 mm when dw is equal to 0.06 mm,

8.8 mm≦

D≦

19.3 mm when dw is equal to 0.07 mm,

24. The flexible tube according to claim 20, wherein said plurality of fine wires are each made of metal.

25. The flexible tube according to claim 22, wherein said plurality of fine wires are each made of a stainless steel.

26. The flexible tube according to claim 22, wherein said plurality of fine wires are each made of a copper alloy.

27. The flexible tube according to claim 22, wherein said plurality of fine wires are each made of a tungsten steel.

28. The flexible tube according to claim 20, wherein said plurality of fine wires comprise metal fine wires and non-metal fine wires.

29. The flexible tube according to claim 26, wherein said non-metal fine wires are made of polyester fibers.

30. The flexible tube according to claim 26, wherein said non-metal fine wires are made of nylon fibers.

31. The flexible tube according to claim 26, wherein said non-metal fine wires are made of carbon fibers.

32. The flexible tube according to claim 1, wherein said flexible tube satisfies the following relationships:

space="preserve" listing-type="equation">45°

≦

α

≦

65°

,

and

space="preserve" listing-type="equation">n=16,

wherein "α

" represents a braid angle and "n" represents a number of strands contained in one of said plurality of strand bundles,

and further wherein said number "n" satisfies all the following relationships;

4.34 D≦

n≦

9.62 D when dw is equal to 0.02 mm,

2.89 D≦

n≦

6.41 D when dw is equal to 0.03 mm,

2.17 D≦

n≦

4.81 D when dw is equal to 0.04 mm,

1.74 D≦

n≦

3.84 D when dw is equal to 0.05 mm,

1.45 D≦

n≦

3.20 D when dw is equal to 0.06 mm,

1.24 D≦

n≦

2.74 D when dw is equal to 0.07 mm,

1.09 D≦

n≦

2.40 D when dw is equal to 0.08 mm,

0.97 D≦

n≦

2.13 D when dw is equal to 0.09 mm,

0.87 D≦

n≦

1.92 D when dw is equal to 0.10 mm, and

0.73 D≦

n≦

1.60 D when dw is equal to 0.12 mm,

wherein "dw" represents a diameter of a strand of each strand bundle in said plurality of strand bundles and "D" represents an average diameter of said netted tube.

33. The flexible tube according to claim 30, wherein a maximum value of said average diameter "D" satisfies all the following relationships:

1.25 mm≦

D≦

2.76 mm when dw is equal to 0.02 mm,

35. The flexible tube according to claim 30, wherein said plurality of fine wires are each made of metal.

36. The flexible tube according to claim 32, wherein said plurality of fine wires are each made of a stainless steel.

37. The flexible tube according to claim 32, wherein said plurality of fine wires are each made of a copper alloy.

38. The flexible tube according to claim 32, wherein said plurality of fine wires are each made of a tungsten steel.

39. The flexible tube according to claim 30, wherein said plurality of fine wires comprise metal fine wires and non-metal fine wires.

40. The flexible tube according to claim 36, wherein said non-metal fine wires are made of polyester fibers.

41. The flexible tube according to claim 36, wherein said non-metal fine wires are made of nylon fibers.

42. The flexible tube according to claim 36, wherein said non-metal fine wires are made of carbon fibers.

43. The flexible tube according to claim 1, wherein said flexible tube satisfies all the following relationships:

space="preserve" listing-type="equation">45°

≦

α

≦

65°

,

and

space="preserve" listing-type="equation">n=8,

wherein "α

" represents a braid angle and "n" represents a number of strands contained in one of said plurality of strand bundles,

and further wherein said number "n" satisfies all the following relationships;

8.67 D≦

n≦

19.24 D when dw is equal to 0.02 mm,

5.78 D≦

n≦

12.82 D when dw is equal to 0.03 mm,

4.34 D≦

n≦

9.62 D when dw is equal to 0.04 mm,

3.47 D≦

n≦

7.69 D when dw is equal to 0.05 mm,

2.89 D≦

n≦

6.41 D when dw is equal to 0.06 mm,

2.48 D≦

n≦

5.49 D when dw is equal to 0.07 mm, and

2.17 D≦

n≦

4.81 D when dw is equal to 0.08 mm,

wherein "dw" represents a diameter of a strand of each strand bundle in said plurality of strand bundles and "D" represents an average diameter of said netted tube.

44. The flexible tube according to claim 40, wherein a maximum value of said average diameter "D" satisfies all the following relationships:

D≦

1.38 mm when dw is equal to 0.02 mm,

D≦

2.07 mm when dw is equal to 0.03 mm,

D≦

2.76 mm when dw is equal to 0.04 mm,

D≦

3.45 mm when dw is equal to 0.05 mm,

D≦

4.15 mm when dw is equal to 0.06 mm,

D≦

4.83 mm when dw is equal to 0.07 mm, and

D≦

5.52 mm when dw is equal to 0.08 mm.

45. The flexible tube according to claim 40, wherein said plurality of fine wires are each made of metal.

46. The flexible tube according to claim 42, wherein said plurality of fine wires are each made of a stainless steel.

47. The flexible tube according to claim 42, wherein said plurality of fine wires are each made of a copper alloy.

48. The flexible tube according to claim 42, wherein said plurality of fine wires are each made of a tungsten steel.

49. The flexible tube according to claim 40, wherein said plurality of fine wires comprise metal fine wires and non-metal fine wires.

50. The flexible tube according to claim 46, wherein said non-metal fine wires are made of polyester fibers.

51. The flexible tube according to claim 46, wherein said non-metal fine wires are made of nylon fibers.

52. The flexible tube according to claim 46, wherein said non-metal fine wires are made of carbon fibers.

54. The flexible tube according to claim 50, wherein said jacket is formed by dissolving a synthetic resin in a solvent and applying a resultant material to said outer surface of said netted tube.

55. The flexible tube according to claim 50, wherein said jacket is formed by heating a thermoplastic synthetic resin at a temperature higher than a softening point of said thermoplastic synthetic resin, so that said thermoplastic synthetic resin penetrates gaps formed in said netted tube from outside said netted tube.

56. The flexible tube according to claim 50, wherein said jacket comprises a synthetic resin consisting of a polyurethane elastomer.

57. The flexible tube according to claim 50, wherein said jacket is formed by firstly covering said netted tube with a synthetic resin formed in a tubular shape, and secondly by heating said synthetic resin at a temperature higher than a softening point of said synthetic resin, so that said synthetic resin penetrates gaps formed in said netted tube from outside said netted tube.

58. The flexible tube according to claim 50, wherein said at least one metal fine wire is made of a stainless steel.

59. The flexible tube according to claim 50, wherein said at least one metal fine wire is made of a copper alloy.

60. The flexible tube according to claim 50, wherein said at least one metal fine wire is made of a tungsten steel.

61. The flexible tube according to claim 50, wherein said at least one non-metal fine wire is made of a polyester fiber.

62. The flexible tube according to claim 50, wherein said at least one non-metal fine wires are made of nylon fibers.

63. The flexible tube according to claim 50, wherein said at least one non-metal fine wires are made of carbon fibers.

65. The netted tube according to claim 61, wherein a maximum value of said average diameter "D" satisfies all the following relationships:

1.9 mm≦

D≦

4.1 mm when dw is equal to 0.02 mm,

2.9 mm≦

D≦

6.2 mm when dw is equal to 0.03 mm,

3.8 mm≦

D≦

8.2 mm when dw is equal to 0.04 mm,

4.7 mm≦

D≦

10.3 mm when dw is equal to 0.05 mm,

5.7 mm≦

D≦

12.3 mm when dw is equal to 0.06 mm,

6.6 mm≦

D≦

14.4 mm when dw is equal to 0.07 mm,

7.5 mm≦

D≦

16.4 mm when dw is equal to 0.08 mm,

8.5 mm≦

D≦

18.4 mm when dw is equal to 0.09 mm,

9.4 mm≦

D≦

20.6 mm when dw is equal to 0.10 mm, and

11.4 mm≦

D≦

24.4 mm when dw is equal to 0.12 mm.

68. The netted tube according to claim 63, wherein a maximum value of said average diameter "D" satisfies all the following relationships:

2.5 mm≦

D≦

5.5 mm when dw is equal to 0.02 mm,

3.8 mm≦

D≦

8.2 mm when dw is equal to 0.03 mm,

5.1 mm≦

D≦

11.0 mm when dw is equal to 0.04 mm,

6.3 mm≦

D≦

13.7 mm when dw is equal to 0.05 mm,

7.5 mm≦

D≦

16.4 mm when dw is equal to 0.06 mm,

8.8 mm≦

D≦

19.3 mm when dw is equal to 0.07 mm,

10.0 mm≦

D≦

21.8 mm when dw is equal to 0.08 mm,

11.4 mm≦

D≦

24.4 mm when dw is equal to 0.09 mm,

12.5 mm≦

D≦

27.2 mm when dw is equal to 0.10 mm, and

15.0 mm≦

D≦

32.4 mm when dw is equal to 0.12 mm.

71. The netted tube according to claim 65, wherein a maximum value of said average diameter "D" satisfies the following relationships:

1.25 mm≦

D≦

2.76 mm when dw is equal to 0.02 mm,

1.88 mm≦

D≦

4.15 mm when dw is equal to 0.03 mm,

2.5 mm≦

D≦

5.5 mm when dw is equal to 0.04 mm,

3.2 mm≦

D≦

6.8 mm when dw is equal to 0.05 mm,

11. 45 D≦

n≦

3.20 D when dw is equal to 0.04 mm,

1.16 D≦

n≦

2.56 D when dw is equal to 0.05 mm,

0.97 D≦

n≦

2.13 D when dw is equal to 0.06 mm,

0.83 D≦

n≦

1.83 D when dw is equal to 0.07 mm,

0.73 D≦

n≦

1.60 D when dw is equal to 0.08 mm,

0.65 D≦

n≦

1.42 D when dw is equal to 0.09 mm,

0.58 D≦

n≦

1.28 D when dw is equal to 0.10 mm, and

0.49 D≦

n≦

1.06 D when dw is equal to 0.12 mm,

wherein "dw" represents a diameter of a strand of each strand bundle in said plurality of strand bundles and "D" represents an average diameter of said netted tube.

23. 0 mm≦

D≦

21.8 mm when dw is equal to 0.08 mm,

11.4 mm≦

D≦

24.4 mm when dw is equal to 0.09 mm,

12.5 mm≦

D≦

27.2 mm when dw is equal to 0.10 mm, and

15.0 mm≦

D≦

32.4 mm when dw is equal to 0.12 mm.

34. 88 mm≦

D≦

4.15 mm when dw is equal to 0.03 mm,

2.5 mm≦

D≦

5.5 mm when dw is equal to 0.04 mm,

3.2 mm≦

D≦

6.8 mm when dw is equal to 0.05 mm,

3.8 mm≦

D≦

8.2 mm when dw is equal to 0.06 mm,

4.4 mm≦

D≦

9.6 mm when dw is equal to 0.07 mm,

5 mm≦

D≦

11 mm when dw is equal to 0.08 mm,

5.7 mm≦

D≦

12.3 mm when dw is equal to 0.09 mm,

6.3 mm≦

D≦

13.7 mm when dw is equal to 0.10 mm, and

7.5 mm≦

D≦

16.4 mm when dw is equal to 0.12 mm.

53. A flexible tube for an endoscope, comprising:

a spiral tube;

a netted tube covering an outer surface of said spiral tube, said netted tube being formed by braiding a plurality of strand bundles each formed by closely arranging a plurality of fine wires in parallel, said plurality of fine wires comprising at least one metal fine wire and at least one non-metal fine wire; and

a jacket made of a flexible synthetic resin which covers an outer surface of said netted tube;

wherein a braid density K of said netted tube lies in a range of 0.788≦

K≦

0.906;

wherein K=(S-s)/S;

wherein "S" is an area of an intersection of two strand bundles in union with an area of a gap between said intersecting strand bundles and neighboring strand bundles of one side of said intersecting strand bundles, the widths of said area "S" being substantially equal; and

wherein "s" is the area of the gap produced by the intersecting strand bundles, wherein no strands are covered, the widths of said area "s" being substantially equal.

64. A netted tube, formed by braiding a plurality of strand bundles each formed by closely arranging a plurality of fine wires in parallel, used in a flexible tube for an endoscope, said flexible tube comprising:

a spiral tube, said netted tube covering an outer surface of said spiral tube; and

a jacket made of a flexible synthetic resin which covers an outer surface of said netted tube;

wherein the following relationships are satisfied;

space="preserve" listing-type="equation">45°

≦

α

≦

65°

,

space="preserve" listing-type="equation">0.772≦

K≦

0.906

and

space="preserve" listing-type="equation">n=24,

wherein "α

" represents a braid angle, "K" represents a braid density, and "n" represents a number of strands contained in one of said plurality of strand bundles,

and further wherein said number "n" satisfies all the following relationships;

2.89 D≦

n≦

6.41 D when dw is equal to 0.02 mm,

1.93 D≦

n≦

4.27 D when dw is equal to 0.03 mm,

1.45 D≦

n≦

3.20 D when dw is equal to 0.04 mm,

1.16 D≦

n≦

2.56 D when dw is equal to 0.05 mm,

0.97 D≦

n≦

2.13 D when dw is equal to 0.06 mm,

0.83 D≦

n≦

1.83 D when dw is equal to 0.07 mm,

0.73 D≦

n≦

1.60 D when dw is equal to 0.08 mm,

0.65 D≦

n≦

1.42 D when dw is equal to 0.09 mm,

0.58 D≦

n≦

1.28 D when dw is equal to 0.10 mm, and

0.49 D≦

n≦

1.06 D when dw is equal to 0.12 mm,

wherein "dw" represents a diameter of a strand of each strand bundle in said plurality of strand bundles and "D" represents an average diameter of said netted tube;

wherein K=(S-s)/S;

wherein "S" is an area of an intersection of two strand bundles in union with an area of a gap between said intersecting strand bundles and neighboring strand bundles of one side of said intersecting strand bundles, the widths of said area "S" being substantially equal; and

wherein "s" is the area of the gap produced by the intersecting strand bundles, wherein no strands are covered, the widths of said area "s" being substantially equal.

66. A netted tube, formed by braiding a plurality of strand bundles each formed by closely arranging a plurality of fine wires in parallel, used in a flexible tube for an endoscope, said flexible tube comprising:

a spiral tube, said netted tube covering an outer surface of said spiral tube; and

a jacket made of a flexible synthetic resin which covers an outer surface of said netted tube;

wherein the following relationships are satisfied;

space="preserve" listing-type="equation">45°

≦

α

≦

65°

,

space="preserve" listing-type="equation">0.772≦

K≦

0.906

and

space="preserve" listing-type="equation">n=32,

wherein "α

" represents a braid angle, "K" represents a braid density, and "n" represents a number of strands contained in one of said plurality of strand bundles,

and further wherein said number "n" satisfies all the following relationships;

67. 17 D≦

n≦

4.81 D when dw is equal to 0.02 mm,

1.45 D≦

n≦

3.20 D when dw is equal to 0.03 mm,

1.09 D≦

n≦

2.40 D when dw is equal to 0.04 mm,

0.87 D≦

n≦

1.92 D when dw is equal to 0.05 mm,

0.73 D≦

n≦

1.60 D when dw is equal to 0.06 mm,

0.62 D≦

n≦

1.37 D when dw is equal to 0.07 mm,

0.55 D≦

n≦

1.20 D when dw is equal to 0.08 mm,

0.49 D≦

n≦

1.06 D when dw is equal to 0.09 mm,

0.44 D≦

n≦

0.96 D when dw is equal to 0.10 mm, and

0.37 D≦

n≦

0.80 D when dw is equal to 0.12 mm,

wherein "dw" represents a diameter of a strand of each strand bundle in said plurality of strand bundles and "D" represents an average diameter of said netted tube;

wherein K=(S-s)/S,

wherein "S" is an area of an intersection of two strand bundles in union with an area of a gap between said intersecting strand bundles and neighboring strand bundles of one side of said intersecting strand bundles, the widths of said area "S" being substantially equal; and

wherein "s" is the area of the gap produced by the intersecting strand bundles, wherein no strands are covered, the widths of said area "s" being substantially equal.

74. The netted tube according to claim 67, wherein a maximum value of said average diameter "D" satisfies all the following relationships:

D≦

1.38 mm when dw is equal to 0.02 mm,

D≦

2.07 mm when dw is equal to 0.03 mm,

D≦

2.76 mm when dw is equal to 0.04 mm,

D≦

3.45 mm when dw is equal to 0.05 mm,

D≦

4.15 mm when dw is equal to 0.06 mm,

D≦

4.83 mm when dw is equal to 0.07 mm, and

D≦

5.52 mm when dw is equal to 0.08 mm.

69. A netted tube, formed by braiding a plurality of strand bundles each formed by closely arranging a plurality of fine wires in parallel, used in a flexible tube for an endoscope, said flexible tube comprising:

a spiral tube, said netted tube covering an outer surface of said spiral tube; and

a jacket made of a flexible synthetic resin which covers an outer surface of said netted tube;

wherein the following relationships are satisfied;

70. °

≦

α

≦

6°

.

space="preserve" listing-type="equation">0.772≦

K≦

0.906

and

space="preserve" listing-type="equation">n=16,

wherein "α

" represents a braid angle, "K" represents a braid density, and "n" represents a number of strands contained in one of said plurality of strand bundles,

and further wherein said number "n" satisfies all the following relationships;

4.34 D≦

n≦

9.62 D when dw is equal to 0.02 mm,

2.89 D≦

n≦

6.41 D when dw is equal to 0.03 mm,

2.17 D≦

n≦

4.81 D when dw is equal to 0.04 mm,

1.74 D≦

n≦

3.84 D when dw is equal to 0.05 mm,

1.45 D≦

n≦

3.20 D when dw is equal to 0.06 mm,

1.24 D≦

n≦

2.74 D when dw is equal to 0.07 mm,

1.09 D≦

n≦

2.40 D when dw is equal to 0.08 mm,

0.97 D≦

n≦

2.13 D when dw is equal to 0.09 mm,

0.87 D≦

n≦

1.92 D when dw is equal to 0.10 mm, and

0.73 D≦

n≦

1.60 D when dw is equal to 0.12 mm,

wherein "dw" represents a diameter of a strand of each strand bundle in said plurality of strand bundles and "D" represents an average diameter of said netted tube;

wherein K=(S-s)/S;

wherein "S" is an area of an intersection of two strand bundles in union with an area of a gap between said intersecting strand bundles and neighboring strand bundles of one side of said intersecting strand bundles, the widths of said area "S" being equal; and

wherein "s" is the area of the gap produced by the intersecting strand bundles, wherein no strands are covered, the widths of said area "s" being equal.

72. 8 mm≦

D≦

8.2 mm when dw is equal to 0.06 mm,

4.4 mm≦

D≦

9.6 mm when dw is equal to 0.07 mm,

5 mm≦

D≦

11 mm when dw is equal to 0.08 mm,

5.7 mm≦

D≦

12.3 mm when dw is equal to 0.09 mm,

6.3 mm≦

D≦

13.7 mm when dw is equal to 0.10 mm, and

7.5 mm≦

D≦

16.4 mm when dw is equal to 0.12 mm.

73. A netted tube, formed by braiding a plurality of strand bundles each formed by closely arranging a plurality of fine wires in parallel, used in a flexible tube for an endoscope, said flexible tube comprising:

a spiral tube, said netted tube covering an outer surface of said spiral tube; and

a jacket made of a flexible synthetic resin which covers an outer surface of said netted tube;

wherein the following relationships are satisfied;

space="preserve" listing-type="equation">45°

α

≦

65°

,

space="preserve" listing-type="equation">0.772≦

K≦

0.906

and

space="preserve" listing-type="equation">n=8,

wherein "α

" represents a braid angle, "K" represents a braid density, and "n" represents a number of strands contained in one of said plurality of strand bundles,

and further wherein said number "n" satisfies all the following relationships;

8.67 D≦

n≦

19.24 D when dw is equal to 0.02 mm,

5.78 D≦

n≦

12.82 D when dw is equal to 0.03 mm,

4.34 D≦

n≦

9.62 D when dw is equal to 0.04 mm,

3.47 D≦

n≦

7.69 D when dw is equal to 0.05 mm,

2.89 D≦

n≦

6.41 D when dw is equal to 0.06 mm,

2.48 D≦

n≦

5.49 D when dw is equal to 0.07 mm, and

2.17 D≦

n≦

4.81 D when dw is equal to 0.08 mm,

wherein "dw" represents a diameter of a strand of each strand bundle in said plurality of strand bundles and "D" represents an average diameter of said netted tubes;

wherein K=(S-s)/S;

wherein "S" is an area of an intersection of two strand bundles in union with an area of a gap between said intersecting strand bundles and neighboring strand bundles of one side of said intersecting strand bundles, the widths of said area "S" being substantially equal; and

wherein "s" is the area of the gap produced by the intersecting strand bundles, wherein no strands are covered, the widths of said area "s" being substantially equal.