U.S. patent number 4,236,509 [Application Number 05/852,640] was granted by the patent office on 1980-12-02 for curving device in an endoscope.
Invention is credited to Nobuhiro Noda, Nagashige Takahashi.
United States Patent |
4,236,509 |
Takahashi , et al. |
December 2, 1980 |
Curving device in an endoscope
Abstract
The curving device in an endoscope is made highly flexible yet
resistant to bending. The guide tube of the curving end section is
provided with a groove or ring-shaped grooves which are formed
respectively spirally or at equal intervals in the outer wall of
the guide tube. The coil is made of a wire whose diameter is
substantially equal to the depth of the groove or grooves and
smaller than the width of the groove or grooves. The coil is fitted
into the groove or grooves in a spiral manner.
Inventors: |
Takahashi; Nagashige
(Itabashi-ku, Tokyo, JP), Noda; Nobuhiro
(Ranzan-machi, Hiki-gun, Saitama, JP) |
Family
ID: |
16029423 |
Appl.
No.: |
05/852,640 |
Filed: |
November 18, 1977 |
Foreign Application Priority Data
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Dec 28, 1976 [JP] |
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51/177350[U] |
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Current U.S.
Class: |
600/139; 138/122;
138/134 |
Current CPC
Class: |
A61B
1/0055 (20130101) |
Current International
Class: |
A61B
1/005 (20060101); A61B 001/00 () |
Field of
Search: |
;128/3,4,5,6,7,8,2M,348,349R,349B,349BV,35R,35V,351,14R,188
;138/121,122,134,133 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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288854 |
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Sep 1931 |
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IT |
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197275 |
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May 1923 |
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GB |
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1383313 |
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Feb 1975 |
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GB |
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Primary Examiner: Michell; Robert W.
Assistant Examiner: Rose; Arthur S.
Attorney, Agent or Firm: Sughrue, Rothwell, Mion, Zinn and
Macpeak
Claims
What is claimed is:
1. In an endoscope of the type comprising a flexible end section
which is inserted into a part to be examined, a manual operating
section for controlling the curving of said flexible end section, a
flexible connecting pipe connecting said flexible end section to
said manual operating section and connecting means in said flexible
pipe coupling said manual operating section and flexible end
section, the improvement in a curving device for said flexible end
section comprising:
a guide tube having a smooth interior surface and having a groove
in the exterior surface thereof, said groove being shaped such that
a wire can be fitted into said groove and wrapped around the tube
in the form of a coil;
a hard wire wrapped around said tube and fitted within and in
direct contact with the surface of said groove along the length of
said tube and forming a coil, the diameter of said wire being
substantially equal to the depth and smaller than the width of said
groove so that said wire is slidable across the width of said
groove during flexing of said tube.
2. The curving device as recited in claim 1 wherein said groove
comprises a spiral groove.
3. The curving device as recited in claim 1 wherein said groove
comprises a plurality of ring-shaped grooves at spaced intervals
along the length of said guide tube and apertures are provided in
the walls of the grooves to permit the wire coil to pass between
adjacent grooves.
4. The curving device as recited in claim 1 wherein said coil of
hard wire is made of steel.
Description
BACKGROUND OF THE INVENTION
This invention relates to an improvement of an inner guide tube
forming the curving end section, made of a flexible thin tube, of
an endoscope, and more particularly to a structure by which the
curving characteristic of the guide tube is improved and the
collapse or abrupt bend thereof is prevented as much as possible
when it is curved.
When the curving end section, made of a flexible thin tube, of an
endoscope is inserted into a part of a human body to be examined,
it is curved smoothly over a wide range of curve angles according
to the conditions of a path to the aimed part of the human body or
by an operating means for feeling for the part. For this curving
operation, two angle wires connecting a manual operating section to
the aforementioned end section are employed. However, if the
curving pressure of the curving section is great, the tensions of
the angle wires are increased in the curving operation. As a
result, the durability of the wires is decreased. Furthermore, if a
force for operating the angle wires is increased, it is rather
difficult for the operator to feel the contact conditions of the
end section with the manual operating section. Therefore, the
operability of the endoscope is lowered.
Therefore, in the endoscope of this type, not only the outer pipe
of the aforementioned flexible thin pipe but also the inner tube of
the same should be so designed as to be readily curved. In order to
meet this requirement, the wall thickness of the tube should be
made thinner since in such a mechanism it is preferable to make the
internal volume of the tube as large as possible and to make the
outside diameter thereof as small as possible. If the wall
thickness of the tube is merely reduced, however, the tube may be
bent when it is curved, which will obstruct the further
operation.
In order to overcome this difficulty, two methods have been
proposed, in one of which a metallic coil whose diameter is such
that the coil can be in close contact with the inner wall of a
conventional tube is inserted thereinto, and in the other of which
a metallic belt coiled to have a diameter which is substantially
equal to the outside diameter of a tube is placed over the outer
wall of the tube. However, the former method is not practical,
because the internal volume of the tube is decreased, which will
obstruct the insertion of forceps or the like, and in addition it
becomes difficult to clean the inside of the tube because the inner
wall of the tube becomes uneven because of the insertion of the
coil, which results in the contamination or infection of bacteria
or bacilli. On the other hand, the latter method is also
disadvantageous because the tube's outside diameter is increased,
and although the bend of the tube may be prevented, it is
unsatisfactory in flexibility because the stiffness of the coil is
added to that of the tube.
In order to overcome the disadvantage caused by the addition of the
coil, there has been proposed a method in which a metallic belt is
wound, in a coil state, around the outer wall of a tube and is then
embedded in the tube by heat treatment. However, this method is
still disadvantageous in that because the metallic belt is embedded
in the tube, shrinkage occurs between the tube and the coil, and it
is unexpectedly poor in flexibility.
SUMMARY OF THE INVENTION
Accordingly, an object of this invention is to eliminate all of the
drawbacks accompanying the conventional end section of the
endoscope. The most significant feature of the invention is to fit
a coil in a groove or grooves provided in the outer wall of a tube
in the end sectin of the endoscope. More specifically, the guide
tube of the curving end section is provided with either a spiral
groove or a plurality of ring-shaped grooves at equal intervals.
The coil is made of hard wire having a diameter substantially equal
to the depth of the groove or grooves and smaller than the width of
the groove or grooves. The coil is not fixed to the tube so that
relative movement can occur therebetween. The structure according
to the invention is both highly flexible and resistant to
bending.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in detail with reference to the
embodiments as shown in the accompanying drawings, in which:
FIG. 1 is a side view illustrating one example of the
endoscope;
FIG. 2 is an enlarged side view, with its one half cut away,
showing essential parts of one embodiment of the device according
to the utility model;
FIG. 3 is an enlarged side view showing essential parts of another
embodiment of the device according to the utility model; and
FIG. 4 is a graphical representation indicating a curvature
characteristic of an endoscope provided with the device according
to the utility model.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, an end section 3 which is inserted into a part
to be examined is connected through a flexible connecting pipe 2 to
a manual operating section. The end section 3 is elevated upward or
downward as viewed in FIG. 1 by turning an operating knob 4
provided on the manual operating section 1.
FIG. 2 is an enlarged view, with one half cut away, illustrating a
part of an inner tube 5 in the end section 3. A groove 6 is
spirally formed in the outer wall of the tube 5. A coil 7 is made
of a steel wire whose diameter is substantially equal to the depth
of the groove 6 but is smaller than the width of the groove 6 (if
it is assumed that the groove 6 is a semi-circular groove, the
diameter of the steel wire is smaller than the diameter of the
semi-circular groove) so that the inner diameter of the wire coil
is substantially equal to the inner diameter d.sub.1 of the spiral
groove and the outer diameter of the wire coil is substantially
equal to the outer diameter d.sub.2 of the spiral groove. The coil
thus formed is fitted into the groove 6.
FIG. 3 is an enlarged side view showing another embodiment of the
tube in the device according to the invention. As shown in FIG. 3,
grooves 6' are provided in the outer wall of a tube 6 at a certain
interval, and one to several longitudinal grooves 6" are formed in
the outer wall of the tube 6 in the longitudinal direciton thereof.
The above-described coil 7 are fitted into the grooves 6' through
the longitudinal grooves 6" as shown in FIG. 3. The coil 7 may be
made of hard synthetic resin or the like instead of steel.
In the device thus constructed according to this invention, the
wall thickness of the tube 5 which is a part of the end section 3
and is curved as required is partially thinner because of the
provision of the grooves 6, 6' and 6". Therefore, it is obvious
that the tube according to the invention can be more readily curved
than other tubes which are not provided with grooves. The coil 7 is
fitted in the groove 6 or the grooves 6' and 6" in close contact
with the bottoms thereof. Therefore, the deformation of the tube is
prevented to a great extent, and the collapse or abrupt bend of the
tube is prevented. It should be noted that the tube 5 and the coil
are not formed into one unit. Therefore, when the tube is curved,
the coil 7 is slid along the groove 6 as the wall of the tube is
extended or contracted; that is, the tube can be curved smoothly.
Thus, the excellent flexibility of the tube 5 due to the thin wall
thickness can be maintained.
FIG. 4 is a characteristic curve diagram with the curve angle Q as
the horizontal axis and with the wire tension g as the vertical
axis. As is apparent from the comparison between the characteristic
curve l.sub.1 for the conventional tube only (Teflon, inside
diameter 2.5 mm, outside diameter 3.1 mm) and the characteristic
curve l.sub.2 for the tube according to this invention (the
conventional tube being provided with seven to eight grooves per
centimeter, the depth of the groove being of the order of 0.1-0.2
mm) with the coil described before, the device according to this
invention becomes effective as the curve angle increases.
In addition, as the coil 7 is fitted into the groove 6 formed in
the outer wall of the tube in such a manner that the outside
diameter is less than the outside diameter of the tube, the outside
diameter of the tube is not increased by the addition of the coil.
Thus, the device according to the invention is quite practical in
use.
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