Surgery – Endoscope – Having flexible tube structure
Reexamination Certificate
1999-03-17
2001-03-27
Dvorak, Linda C. M. (Department: 3739)
Surgery
Endoscope
Having flexible tube structure
C600S140000, C604S524000, C604S526000, C604S527000
Reexamination Certificate
active
06206824
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flexible tube for an endoscope used as an inserting part of an endoscope. The present invention also relates to a method of producing the flexible tube.
2. Description of the Related Art
Flexible tubes for an endoscope are generally formed in such a manner that a spiral coil having one or more superposed layers are covered with a reticulate tube, which in turn is covered with a flexible jacket. The flexible jacket is formed by either of covering a flexible tube material therewith or applying a molten thermoplastic synthetic resin material on the reticulate tube and curing the applied layer.
FIG. 6
shows a conventional flexible tube for the endoscope, which has a jacket
13
formed by first applying a molten thermoplastic synthetic resin material and then curing the applied layer. Obviously, a jacket material
1
has penetrated through openings in the reticulate tube
12
to bind the jacket
13
and the reticulate tube
12
. A reference numeral
11
represents a spiral coil
11
.
However, a combination between the spiral coil
11
and the reticulate tube
12
is so weak that as the result of repeat use of the endoscope, gaps form between the two members
11
and
12
and the flexible tube becomes increasingly soft to introduce difficulty in inserting the endoscope into a body cavity.
Another problem in the conventional flexible tube for the endoscope is shown in FIG.
7
. When using the flexible tube, the flexible tube bends in various directions at small radii of curvature or reverts to a straight form. As a result, a silicone rubber tube covering a bundle of optical fibers
50
passing through the flexible tube is damaged by inner edges of the spiral coil
11
, often causing the internal optical fibers to break and become deteriorated in optical performance.
SUMMARY OF THE INVENTION
An object, therefore, of the present invention is to solve the aforementioned problems and to provide a flexible tube for an endoscope, which can be repeatedly used while an inner surface of an innermost spiral coil does not damage an internally passing optical fiber bundle and the like and the flexible tube hardly varies in flexibility.
Another object of the invention is to provide a method of producing the flexible tube for the endoscope.
According to a first aspect of the present invention, there is provided a flexible tube for an endoscope comprising:
a spiral coil defining gaps between adjacent turns of said spiral coil; and
a jacket formed by a jacket material and covering at least an outer surface of said spiral coil;
wherein said jacket material penetrates through said gaps to cover at least edges of said spiral coil.
According to a second aspect of the present invention, there is provided the flexible tube as described in the first aspect of the present invention, wherein said spiral coil includes one or more superposed layers which are covered with one or more layers of a reticulate tube, and said reticulate tube is embedded in said jacket material.
According to a third aspect of the present invention, there is provided the flexible tube as described in the first aspect of the present invention, wherein the inner surface of said spiral coil is entirely covered with said jacket material.
According to a fourth aspect of the present invention, there is provided a method of producing a flexible tube for an endoscope comprising the steps of:
setting a spiral coil as an innermost layer on a mandrel with a clearance between an outer surface of said mandrel and an inner surface of said spiral coil;
applying a melt of a jacket material onto said spiral coil to penetrate through gaps between adjacent turns of said spiral coil into said clearance;
curing said jacket material; and
removing said mandrel.
According to a fifth aspect of the present invention, there is provided the method as described in the fourth aspect of the present invention, wherein said spiral coil contains one or more superposed layers.
According to a sixth aspect of the present invention, there is provided the method as described in the fourth aspect of the present invention, further comprising the step of:
covering said spiral coil with one or more layers of a reticulate tube after setting said spiral coil.
According to a seventh aspect of the present invention, there is provided a method as described in the fourth aspect of the present invention, wherein said jacket material is a thermoplastic synthetic resin and applied with an extrusion molding machine.
According to an eighth aspect of the present invention, there is provided a method as described in the fourth aspect of the present invention, further comprising the step of:
conducting a bond enhancing treatment to members to which said jacket material is applied before applying said jacket material onto said spiral coil.
According to a ninth aspect of the present invention, there is provided a method as described in the fourth aspect of the present invention, wherein said members are said spiral coil and a reticulate tube.
According to the present invention, the jacket material that is cured after being applied in a molten state is allowed to penetrate through gaps between adjacent layers of the spiral coil as the innermost layer until it reaches the portions of the inner surface of the spiral coil. Therefore, the inner edges of the spiral coil can be covered with the jacket material. Hence, the flexible tube for the endoscope of the present invention permits a repeat use of an endoscope without causing the internally passing optical fiber bundle and the like to be damaged by the inner surface of the innermost spiral coil. If the inner surface of the spiral coil are all or in part covered with the penetration of the jacket material, the bond between the spiral coil and other member is sufficiently enhanced to reduce the variations in flexibility that will occur after the repeat use of the endoscope.
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Hirose Hitoshi
Iwasaka Kikuo
Kasai Tadashi
Kubota Tatsuo
Ohara Kenichi
Asahi Kogaku Kogyo Kabushiki Kaisha
Dvorak Linda C. M.
Greenblum & Bernstein P.L.C.
Ram Jocelyn
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