U.S. patent number 3,910,279 [Application Number 05/480,855] was granted by the patent office on 1975-10-07 for electrosurgical instrument.
This patent grant is currently assigned to Olympus Optical Co., Ltd.. Invention is credited to Kazuhiko Mitsui, Takeshi Okada.
United States Patent |
3,910,279 |
Okada , et al. |
October 7, 1975 |
Electrosurgical instrument
Abstract
In the forward end portion of the flexible insulating tube of an
electrosurgical instrument there is formed an opening or fenestra
at the side surface thereof, and when an electrode wire is forced
into the insulating tube, the working section thereof is outwardly
looped through said opening, so that said looped working section is
brought into contact with the tissue of the body cavity to resect
the same. This instrument is introduced into a predetermined
position of the body cavity using an endoscope while an operator is
observing the endoscope.
Inventors: |
Okada; Takeshi (Hachioji,
JA), Mitsui; Kazuhiko (Tokyo, JA) |
Assignee: |
Olympus Optical Co., Ltd.
(Tokyo, JA)
|
Family
ID: |
28242485 |
Appl.
No.: |
05/480,855 |
Filed: |
June 19, 1974 |
Foreign Application Priority Data
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|
|
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Jun 20, 1973 [JA] |
|
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48-72170[U] |
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Current U.S.
Class: |
606/47 |
Current CPC
Class: |
A61B
18/14 (20130101); A61B 2018/1407 (20130101); A61B
18/1492 (20130101); A61B 17/32056 (20130101) |
Current International
Class: |
A61B
18/14 (20060101); A61B 17/32 (20060101); A61B
017/32 () |
Field of
Search: |
;128/303.15,303.13,303.14,303.16,303.17,345 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Cohen; Lee S.
Claims
What we claim is:
1. An electrosurgical instrument for resecting the tissue of a body
cavity comprising:
a flexible insulating tube including a forward end portion
substantially straight along the axial line of the tube and having
a fixed tip end and a pair of axially aligned holes formed in a
side of the forward end portion of the tube;
a flexible electrode wire affixed to said tip end and capable of
being manually forced into and withdrawn from the tube along its
axis, said electrode wire including a body section having a base
end disposed within said tube lengthwise thereof, an end section
fixed within the tip end of the forward end portion of the tube and
a working section outside of the tube having both of its ends
respectively connected to the body section and the end section and
projectively looped in an axial plane through said pair of holes
and radially adjustable in response to the force exerted on said
electrode wire; and
means for connecting said base end of the body section to a source
of electric current including means to radially adjust the working
section whereby said looped working section may be brought into
contact with the tissue of the body cavity thereby to resect said
tissue.
2. An electrosurgical instrument according to claim 1, wherein said
flexible electrode wire is a single wire.
3. An electrosurgical instrument according to claim 1, which
further comprises a second pair of axially aligned holes formed in
a side of said forward end portion of the tube, a second flexible
electrode wire capable of being manually forced into and withdrawn
from the tube along its axis and having a second body section
disposed within the tube lengthwise thereof and secured to the body
section of the first aforesaid electrode wire, and a second end
section fixed within the tip end of the forward end portion
together with the end section of the first aforesaid electrode wire
and a second working section outside of the tube disposed between
said second body section and said second end section and
projectively looped in another axial plane through said second pair
of holes and radially adjustable in response to the force exerted
on both electrode wires, said second body section being connected
to said connecting means.
4. An electrosurgical instrument according to claim 1, which
further comprises a grip member secured to a base end of the
insulating tube and having an insertion hole for allowing said
electrode wire to be inserted therethrough in the axial direction
of the tube, a grip surface at its outer circumference, and a rigid
guide pipe covering the electrode wire at the base end of the body
section and slidably extending through the insertion hole of the
grip member, thereby to prevent the electrode wire from buckling
during insertion and withdrawal of said wire, said connecting means
including a manually operable knob member secured to said guide
pipe.
5. An electrosurgical instrument according to claim 1, which
further comprises a second electrode wire having a second working
section outside of the tube and having one end thereof connected to
the body section of said first aforesaid electrode wire and the
other end fixed within the tip end of said forward end portion;
a second pair of axially aligned holes provided for different
portions of the side of the forward end portion of the tube, said
second working section being connected to the body section and tip
end and being projectively looped in another plane in relation to
the axial line of the tube through said second pair of holes
transversely with respect to said axial line.
6. An electrosurgical instrument according to claim 5, wherein the
body section of the electrode wire is constructed of a single wire
larger in thickness than that of each respective working section.
Description
BACKGROUND OF THE INVENTION
This invention relates to an electrosurgical instrument for
resecting the tissue of body cavity of a human being.
An example of the prior art electrosurgical instrument of this type
is disclosed in the respective specifications of, for example, U.S.
Pat. Nos. 2,018,335 and 2,545,865. In the electrosurgical
instrument shown in these U.S. patent specifications, an electrode
shaped into a loop at its tip end portion is exteriorly extended
from the fenestra formed in the distal end of the endoscopic tube.
Said looped working section of the electrode is arranged in a
substantially transverse direction to the axial line of the tube,
and by causing said section to contact the tissue of the body
cavity the electrosurgical resection operation of cutting or
coagulating the body tissue is carried out. Said electrode is so
constructed as to slide the looped working section longitudinally
of the tube.
In the electrosurgical instrument having such a construction,
however, the fenestra formed in the distal end of the tube should
be large enough to enable the looped working section to slide
therethrough. But where the fenestra is rendered large, the
peripheral portion thereof and the structural portion within the
tube unpreferably contact the inner wall of the body cavity during
the resection operation to damage often the body tissue.
Further, where the fenestra is rendered large, a large amount of
body liquid is entered into the tube from said fenestra during the
resection operation to break the insulating condition. Therefore,
measures for preventing the breakage of the insulating condition
should previously be taken, which results in a complicated
structure of the instrument.
Where it is desired to insert the tube particularly into a
relatively fine or narrow body cavity and spread the inlet or
outlet portion of the body cavity by operation of the instrument,
the looped working section is made to abut against said inlet or
outlet portion to be unpreferably bent or interrupted from
sufficiently contacting the same because the looped working section
is arranged transversely to the axial line of the tube.
Furthermore, since, in the instrument having the conventional
construction, the endoscopic tube is formed of rigid material and
therefore has no high flexibility, the places in the body organ or
cavity where the resection operation can be performed are limited,
failing to sufficiently carry out the required resection operation
using this instrument.
SUMMARY OF THE INVENTION
This invention is characterized in that for the purpose of solving
various problems arising from the electrosurgical instrument having
the conventional construction the working section of the electrode
wire having a body section disposed lengthwise within the
insulating tube, said working section being designed to be directly
contacted with the body tissue, is made to round out in the form of
a loop with respect to the axial line of the tube on the same plane
including said axial line via the opening formed at the side
surface of the distal end or forward end of the tube; and that the
insulating tube and electrode wire are respectively formed of
material having high flexibility. The aforesaid characterizing
construction of the invention enables the narrowing of the opening
for allowing the working section of the insulating wire to be
looped, so that entry of body liquid into the tube is prevented to
a minimum extent and simultaneously there is no fear of damaging
the inner wall of the body cavity during the resection operation.
Further, since the working section is outwardly looped from the
opening along the axial direction of the tube, it is effectively
contacted with the inlet or outlet portion of the body cavity,
thereby enabling a sufficient resection operation at said portion
to be performed. Further, since the tube and wire have high
flexibility, the tube can be brought to a given position within the
body organ or cavity which is to be resected.
In the preferred embodiment of the invention, the insulating tube
is inserted through the endoscope and inserted together with the
endoscope into the body organ or cavity while said endoscope is
being observed by a viewer or an operator. Accordingly, it is
possible to quickly and exactly bring the instrument to a desired
position to be subjected to the resection operation, so that the
operation range has been extremely enlarged. Further, since the
insulating tube is integrally formed of, for example,
polytetrafluoroethylene resin known under the name of "Teflon," and
the electrode wire is integrally formed of stainless steel, the
instrument is made simple in construction and the instrument
trouble has been reduced in number. Provided for the base portion
of the insulating tube is a grip member for being manually operated
by a viewer or an operator. Simultaneously mounted on the base
section of the electrode wire is a knob member. For this reason, if
the operator manually operates said grip member and knob member,
the working section of the wire will be able to be outwardly looped
with ease and the looping degrees will be able to be simultaneously
adjusted.
The later described embodiments illustrate the manner in which the
electrosurgical instrument according to the invention is introduced
into the body organ or cavity using the endoscope, but it is also
possible to introduce said instrument alone directly into the body
organ or cavity. In the instrument having a construction permitting
such direct introduction, means for observing the interior of the
body organ or cavity, such as a fiber bundle-made image guide is
provided in a manner extending from the forward end or distal end
of the tube into the tube.
Accordingly, a first object of the invention is to provide an
electrosurgical instrument capable of resecting the tissue of the
inner wall of the body cavity with high efficiency.
A second object of the invention is to provide an electrosurgical
instrument capable of performing the tissue resection in a given
place within the body cavity where resection is needed.
A third object of the invention is to provide an electrosurgical
instrument which can be made simple in construction and therefore
manufactured at low cost and which has high securability with
respect to the living body during the use.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal sectional view of the forward end section
of an electrosurgical instrument according to an embodiment of the
invention;
FIG. 2 is a plan view, partly in section, of the forward end
section of the instrument shown in FIG. 1;
FIG. 3 is a side view, partly broken, of the base section of the
instrument shown in FIG. 1;
FIG. 4 illustrates the manner in which the instrument of FIG. 1 is
introduced into the body cavity using the endoscope to permit the
resection of the tissue of the body cavity;
FIG. 5 is a longitudinal sectional view of the forward end section
of an electrosurgical instrument according to a second embodiment
of the invention;
FIG. 6 is a plan view of the forward end section of the instrument
shown in FIG. 5;
FIG. 7 is a longitudinal sectional view of the forward end section
of an electrosurgical instrument according to a third embodiment of
the invention;
FIG. 8 is a cross sectional view on line 8--8 of FIG. 7;
FIG. 9 is a longitudinal sectional view of the forward end section
of an electrosurgical instrument according to a fourth embodiment
of the invention; and
FIG. 10 is a longitudinal sectional view of the forward end section
of an electrosurgical instrument according to a fifth embodiment of
the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the forward end section of an electrosurgical instrument shown
in FIGS. 1 and 2, an insulating tube 1 is formed of material having
high flexibility such as a polytetra-fluoroethylene resin known
under the name of "Teflon." The forward end portion 1a of the tube
1 is formed at its side surface with two through holes 2a and 2b
spaced from each other at a prescribed interval along the axial
line of the tube 1. Said both holes 2a and 2b constitute openings
or fenestras 2 for permitting the passage of the working section of
an electrode wire 3. Said electrode wire 3 is a single flexible
wire prepared, for example, by twisting a large number of fine
stainless stell elements together. Said wire 3 is divided into
three sections, namely, a body section 4, end section 5 and working
section 6 though they are not mutually discriminated in the
illustrations by clear boundary lines. The body section 4 has a
base end 7 as later described, and is disposed lengthwise of the
tube 1 within the same. The end section 5 of the wire 3 is fixed
within the tip end of the forward end portion 1a of the tube by
fixing means, for example, the silver soldering. The working
section 6 between said end section 5 and body section 4 is a
section for performing the resection operation by direct contact
with the tissue of the body cavity, and succeeds the body section 4
at one end via said through hole 2a and succeeds the end section 5
at the other end via said through hole 2b. The working section 6 is
wholly exposed to the exterior of the tube 1. When, as later
described, the wire 3 is pushed toward the forward end portion 1a
along the axial line of the tube 1 as indicated by an arrow of FIG.
1, it is made to round out in the form of a large loop transversely
to the axial line of the tube 1 as denoted by two dots-and-dash
lines of FIG. 1. The rounding-out operation of the working section
6 is performed on the same plane including the axial line of the
tube 1. In other words, upon pushing-into operation of the wire 3
the working section 6 is outwardly looped in a manner going away
from the outer circumference of the tube 1 along the axial line
thereof, and, upon drawing-out operation of the wire 3, conversely
is shrunk in a manner approaching said outer circumference. The
pushing-into or drawing-out operation by an operator of the wire 3
is carried out along the axial line of the tube 1. As seen from the
conditions of the working sections 6 indicated by solid lines and
two dots-and-dash lines, the length of the working section 6 of the
wire 3 is made larger under the looped condition indicated by the
two dots-and-dash lines, so that the length of the body section 4
is made smaller by that extent. It can be considered that the
boundary line between the working section 6 and the body section 4
is varied in position with the pushing-into or drawing-out
operation of the wire 3. Similarly, the boundary line between the
working section 6 and the end section 5 will be somewhat varied in
position, though extremely slightly.
In the base section of the electrosurgical instrument shown in FIG.
3, the base end portion 1b of the tube 1 is slightly enlarged in
diameter, and a grip member 9 is fitted at one end into said
enlarged base end portion 1b in alignment with the axial line of
the tube 1. The grip member 9 has a wire insertion hole 10 in
alignment with the axial line of the tube 1. The other end portion
of the grip menber 9 is enlarged and has at its outer circumference
a semicircle-shaped grip surface 9a, which is so formed that an
operator can easily take hold of said grip surface 9a with his
fingers as shown. The base section 4 of said electrode wire 3 is
inserted into the wire insertion hole 10 of the grip member 9, and
is extended from said other end portion of the grip member 9.
Mounted onto the extended base end portion 7 of the wire is a knob
member 11. The base end portion 7 of the wire 3 within the knob
member 11 is electrically connected to an output code 13 by means
of a connector 12. The output code 13 is connected to a proper
current supply source not shown. A high frequency current is flowed
in the base end 7 of the wire 3 via the output code 13 and the
connector 12 from said source. Said high frequency current is
supplied from the base end portion 7 to the looped working section
6 through the wire 3, and the looped working section 6 supplied
with said current is brought into contact with the tissue of the
body cavity, thereby to cut or coagulate the same.
As shown in FIG. 3, the operator can take hold of said knob member
11 with his fingers as in the case of the grip member 9.
It is to be noted that the knob member 11 and grip member 9 are
both formed of a proper insulating material such as a synthetic
resin.
Referring to FIG. 4, the endoscope 14 is in a state inserted into
the duodenum 15 constituting the body organ of a human being. In
said state, the distal end 14a of the endoscope 14 just reaches the
vicinity of the pancreatic duct 16 opened to the duodenum. This
endoscope 14 is of a general construction, and introduction of the
endoscope 14 into the duodenum 15 is carried out while the operator
or viewer is observing the interior of the body cavity via a proper
observation means provided within the endoscope 14. For this
reason, said introduction of the endoscope is smoothly performed,
so that it is possible to quickly bring the distal end to a
diseased part within the body cavity which is to be observed. Said
observation means includes, for example, an eyepiece disposed
within the proximal end portion of the endoscope 14 not shown, an
image guide consisting of a flexible fiber bundle disposed within
the endoscope and lengthwise thereof, and an objective lens
disposed within the distal end 14a. These constituent elements,
however, are of a general construction, and the illustrations
thereof are omitted.
Provided for the side surface of the distal end 14a are an image
guide window 17, illumination light guide window 18 and fluid
suction port 19, which however are also known.
Also provided for the side surface of the distal end 14a is a
window opening 20 for allowing the electrosurgical instrument to be
projected therethrough. This window opening 20 communicates with an
instrument insertion channel 21 formed in a manner extending from
the distal end 14a into the endoscope 14.
Into said insertion channel 21 is inserted the electrosurgical
instrument according to the invention, the forward end portion 1a
of which is projected into the body cavity through the window
opening 20. At the projecting time, the working section 6 of the
wire 3 is shrunk to a state contacting the outer circumference of
the tube 1 of the instrument. When, thereafter, the operator or
viewer has found, while observing the outlet portion 16a of the
pancreatic duct 16 opened to the duodenum 15, that said outlet
portion is extremely narrowed, and has to resect partially the
tissue of the outlet portion 16a by means of the instrument for the
purpose of enlarging said narrowed outlet portion 16a, the
resection operation is carried out as follows. While the forward
end portion 1a of the tube 1 of the instrument is being inserted
into the outlet portion 16a of the pancreatic duct 16, the working
section 6 is outwardly looped as shown in FIG. 4. While the
outwardly looped working section 6 is pressing the tissue of the
narrowed outlet portion 16a in a manner to enlarge the outlet
portion 16a, the section 6 resects the pressed tissue by the high
frequency current flowing through the section 6. Since the working
section 6 performing the resection operation as such is in a state
ourwardly looped in the same plane including the axial line of the
tube 1 as previously described, the working section 6, even when
the tube 1 is brought into contact with the body tissue while being
inserted deeply into the pancreatic duct 16, maintains its
sufficient rigidity without being bent by said body tissue. In this
manner, the looped working section 6 cuts or coagulate for
resection the tissue of the narrowed outlet portion 16a of the
pancreatic duct 16, enabling the outlet portion to be enlarged to a
sufficiently large size. As the result, communication of the
pancreatic duct 16 with the duodenum is sufficiently attained, thus
executing the desired medical treatment.
The operation for looping the working section 6 is carried out by
manually operating the grip member 9 and the knob member 11 shown
in FIG. 3. Namely, the operator moves the knob member 11 in a
direction in which it approaches the grip member 9, with the grip
member 9 held by the fingers of one hand and the knob member 11
held by the fingers of another. Then, the wire 3 is forced into the
tube 1 to permit the working section 6 to be outwardly looped as
indicated by two dots-and-dash lines of FIG. 1. On the other hand,
if the operator moves the knob member 11 in a direction in which it
goes away from the grip member 9, the wire 3 will be drawn out from
the tube 1, so that the working section 6 is returned to the shrunk
state indicated by solid lines from the looped state indicated by
two dots-and-dash lines.
The wire 3 is covered with a rigid guide pipe 22 by the extent of a
predetermined length extending from its base end 7. Said guide pipe
22 is inserted through the wire insertion hole 10 provided for the
grip member 9, and so acts as to maintain the wire 3 straight in
cooperation with said hole 10. The guide pipe 22 functions to
prevent the wire 3 from buckling at the above-mentioned
forcing-into or drawing-out operation time. For this reason, such
operation can smoothly be performed with safety.
In FIGS. 5 and 6, the forward end section of an electro-surgical
instrument according to a second embodiment of the invention is
only illustrated. Since, however, the base end section has the same
construction as that illustrated in FIG. 3, the illustration
thereof is omitted. In the forward end section of the instrument
shown here in FIGS. 5 and 6, the same parts end sections as those
of FIGS. 1 and 2 are denoted by the same reference numerals. The
difference between the construction shown in FIGS. 5 and 6 and that
shown in FIGS. 1 and 2 resides in that the opening 2 in the latter
construction is constituted by the two through holes 2a and 2b
whereas the opening 2 in the former is constituted by an elongate
slot having a prescribed length. This elongate slot 2 is formed
lengthwise of the flexible insulating tube 1 in the side surface of
the forward end portion 1a thereof. The working section 6 of the
wire 3 within the tube 1 is outwardly projectively looped from the
shrunk position indicated by solid lines of FIG. 5 to the position
indicated by two dots-and-dash lines through the elongate slot 2.
Said projectively looped working section 6 is made to contact the
tissue of the body cavity for resecting the same. In FIG. 5, in the
shrunk position, the working section 6 is in a state wholly hidden
within the tube 1. Also in such shrunk position, however, the
working section 6 may be exposed somewhat exteriorly of the tube 1
from the elongate slot 2.
It is to be noted that the body section 4 and end section 5 of the
wire 3 have the same construction as those illustrated in FIGS. 1
and 2.
In FIGS. 7 and 8, the forward end section of an electrosurgical
instrument according to a third embodiment of the invention is only
illustrated. Since, however, the base end section thereof has the
same construction as that illustrated in FIG. 3, the illustration
thereof is omitted. The difference between the construction shown
in FIGS. 7 and 8 and that shown in FIGS. 1 and 2 resides in that in
the latter construction a single wire 3 and a pair of through holes
2a and 2b therefor are provided whereas in the former construction
an additional wire 30 and an additional pair of through holes 2c
and 2d for allowing said wire 30 to be passed therethrough are
provided. That is to say, in the instrument shown in FIGS. 7 and 8,
the additional wire 30 is a single electrode wire prepared by
twisting a number of fine stainless steel elements together and has
high flexibility, as in the case of the wire 3. The body section 40
of the wire 30 is disposed lengthwise of the tube 1 within the same
in a state gathered together with the body section 4 of the wire 3.
Said both body sections 4 and 40 are covered by a cover tube 23.
The end section 50 of the wire 30 is fixed within the tube 1 by the
fixing means 8, for example, by the silver soldering jointly with
the end section 5 of the wire 3. The working section 60 between the
end section 50 and the body section 40 is projectively looped
outwardly of the tube 1 via the through holes 2c and 2d in a
diametrical direction and yet in a direction opposite to that in
which the working section 6 is looped. As clearly seen from FIG. 8,
the looping plane of the working section 60 is flush with a flat
plane including the axial line of the tube 1, and said flat plane
is the same as the looping plane of the working section 6.
Accordingly, said additional pair of through holes 2c and 2d are
formed, along the axial line thereof at a prescribed interval in a
state spaced from each other, in those portions of the tube 1 which
diametrically oppose said pair of through holes 2a and 2b.
In FIG. 7, the condition in which the wires 3 and 30 are forced
into the tube 1 to permit both working sections 6 and 60 to be
largely looped exteriorly of the tube 1 is shown. Under this
condition, a high frequency current is flowed in both looped
working sections 6 and 60, which are brought into contact with the
tissue of the body cavity, thereby performing the resection of said
tissue.
If, as above described, two or more electrode wires are disposed
within the tube 1, thereby to permit a plurality of working
sections to be projectively looped from the outer circumference of
the tube 1 in different directions, the operation for resecting the
body tissue will more quickly be carried out. Furthermore,
according to the invention, a plurality of wires are all gathered
or collected into a single bundle within the body section, so that
the operations by the operator are the same as in the case of a
single wire.
In the case shown in FIGS. 7 and 8, the working section 60 of the
wire 30 may not necessarily be so constructed as to diametrically
oppose the working section 6 of the wire 3. Accordingly, the
looping plane of the working section 60 may not be made flush with
that of the working section 6. Accordingly, the pair of through
holes 2c and 2d may not diametrically oppose the through holes 2a
and 2b.
The through holes 2c and 2d constitute the opening 2 of the tube 1
together with the through holes 2a and 2b. As will be understood
from the previously described embodiments, the opening 2 may be
formed small because it has only to have a size permitting the
passage of a fine electrode wire 3. Further, during the resection
operation the working section is in a state passed through the
opening 2, so that entry of body liquid into the tube 1 is
extremely avoided.
An electrosurgical instrument according to a fourth embodiment
shown in FIG. 9 has almost the same construction as that shown in
FIG. 7. The difference therebetween only resides in that in the
construction of FIG. 9 the body section 400 corresponding to those
of the wires 3 and 30 of FIG. 7 is constituted by a single
relatively thick conductive wire having a large thickness than that
of the working section. The forward end of the body section 400 is
rigidly connected at 400a to the rearward ends of the working
sections 6 and 60, for example, by the welding process. When the
body section 400 is pushed in an arrow-indicated direction by the
manual operation of the operator, the both working sections 6 and
60 are projectively looped exteriorly of the tube 1. On the other
hand, when the body section 400 is pulled in the opposite
direction, the two looped working sections 6 and 60 are shrunk at
the same time. If the body section 400 is constituted by a single
relatively thick wire larger in thickness than that of the working
section as in this embodiment, the fear will be more reduced that
the body section is buckled when pushed into or drawn out from the
tube 1. It is to be noted that the end sections 5 and 50 can also
be constituted by a single wire. In other words, it is possible
that the working section alone is constituted by a plurality of
relatively thin electrode wires whereas the remaining sections by a
single common wire.
An electrosurgical instrument according to a fifth embodiment shown
in FIG. 10 has almost the same construction as that shown in FIG.
7. The difference therebetween only resides in that in the
construction of FIG. 10 one electrode wire 30 has no body section
and the body section 4 of the other electrode wire 3 is
concurrently used for both wires 3 and 30. One end of the working
section 60 of the wire 30 is secured to one end of the working
section 6 of the wire 3, for example, by the welding process.
Accordingly, when the body section 4 is pushed in an
arrow-indicated direction, the both working sections 6 and 60 are
respectively projectively looped exteriorly of the tube 1. On the
other hand, when the body section 4 is pulled in the opposite
direction, the both looped working sections are shrunk at the same
time. It is to be noted that construction can be made such that the
both ends of the working section 60 of the wire 30 are secured to
the both ends of the working section 6 of the wire 3. If
arrangement is made as such, the end section 50 of the wire 30 will
not be required and the end section 5 will concurrently function as
the section 50.
* * * * *