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Description  |
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BACKGROUND OF THE INVENTION
This invention relates to a suction control device in an endoscope, which
is used to remove mucus, dirty substance or the like in the human body
cavity through an endoscope channel.
Generally, a suction control device in an endoscope serves, in addition to
the original function of controlling the sucking out of mucus, dirty
substance etc. in the human body cavity, to lead a medical fluid, as well
as a medical instrument such as forceps, into the channel of the
endoscope. A conventional suction control device for an endoscope
comprises, as shown in FIG. 1, a mounting tube 1 provided on the operating
section 2 of the endoscope, a hollow cylindrical member 3 tightly fitted
into the mounting tube 1 and having its distal end communicating with a
corresponding channel of the endoscope, and an inner tube assembly 4
coaxially inserted into the hollow cylindrical member 3. An air chamber 5
is defined by the inner surface of a larger diameter portion of the hollow
cylindrical member 3 and outer surface of the inner tube assembly 4 and
communicates with the endoscope channel and with a suction tube 6
projecting from the side wall of the hollow cylindrical member 3. A
metallic cap 7 is fitted over the proximal end of the hollow cylindrical
member 3 and has a central hole 8 communicating with the interior of the
inner tube assembly 4. The central hole 8 of the cap 7 is adapted to be
blocked by a finger cushion so as to take out through the endoscope
channel, mucus, dirty substances etc. in the body cavity of the human
being. Since, however, the cap of the conventional control device is made
of metal, no sufficient contact is assured between the inner peripheral
edge of the central hole 8 of the cap 7 and the finger cushion. In other
words, air leaks into the inner pipe assembly 4 from between the inner
peripheral edge of the central hole 8 of the cap 7 and the finger cushion,
failing to sufficiently remove mucus, dirty substance etc. from the human
body cavity. It is a usual practice to operate various levers of the
endoscope operating section 2 by the thumb and block the central hole 8 of
the cap by the index finger of the same hand. Since, however, the cap 7
lacks flexibility, it is not easy for the user to quickly block the
control hole 8 of the cap 7 as required. The mere placement of the index
finger over the central hole 8 of the cap 7 is sometimes insufficient to
completely block the central hole 8 of the cap 7. Furthermore, where an
elongated medical instrument such as forceps is used, the central hole 8
of the cap 7 can not be blocked by the human finger, since the instrument
is inserted into the inner pipe assembly 4. As a result, a sucking
capability is markedly reduced.
SUMMARY OF THE INVENTION
It is accordingly the object of this invention to provide a suction control
device in an endoscope, in which air inlets of the cap can be readily,
quickly and positively blocked by the finger cushion during a suction
operation, and in which, even when an elongated medical instrument
including forceps is inserted into the endoscope, a suction operation can
be positively controlled.
According to this invention, there is provided a suction control device in
an endoscope, comprising an outer tube assembly having one end connected
to the proximal end of the endoscope, an inner tube assembly coaxially
inserted into the outer tube assembly, an air chamber defined between the
inner and outer tube assemblies communicating with the interior of a
distal end portion of the inner tube assembly, an air suction pipe
extending from the lateral wall of the outer tube assembly and
communicating with the air chamber, a flexible cap mounted on the proximal
end of the outer tube assembly, a first air inlet formed in the cap for
conducting air into the inner tube assembly, a second air inlet formed in
the cap for conducting air into the air chamber, and a sealing means
provided in the inner tube assembly for sealing the interior of the distal
end portion of the inner tube assembly from the interior of the proximal
end thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a longitudinal sectional view of a prior art suction control
device in an endoscope;
FIG. 2 shows a longitudinal cross sectional view of an embodiment of this
invention with an elongated medical instrument inserted thereinto;
FIG. 3 shows a plan view of a cap of FIG. 2;
FIG. 4 shows a longitudinal cross sectional view of the same embodiment as
of FIG. 1 with a finger cushion pressed against air inlets of a cap of the
device;
FIG. 5 shows a partially broken front view of the same embodiment as of
FIG. 1 with a finger cushion pressed against air inlets of a cap of the
device in a manner different from that of FIG. 3;
FIG. 6 shows a longitudinal cross sectional view of another embodiment of
this invention; and
FIG. 7 shows a partially broken front view of a further embodiment of this
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Like reference numerals are employed to designate identical or similar
parts or elements throughout the specification and, with respect to parts
or elements already explained in a preceding embodiment, further
explanation will be omitted so as to avoid unnecessary duplication.
Referring to FIGS. 2, 4 and 5 a suction control device for an endoscope
comprises an outer tube assembly 11 and an inner tube assembly 12
coaxially inserted into the outer tube assembly 11. The outer tube
assembly 11 comprises a metallic mounting tube 13 placed in an operating
section (not shown) of an endoscope and having its distal end connected to
an endoscope channel 10, and a metallic hollow cylindrical member 14
inserted into the mounting tube 13. At the distal end portion of the
member 14 is formed an annular stepped portion 15 having a central hole 16
smaller than the inner diameter of the remaining major portion of the
cylindrical member 14. The inner tube assembly 12 comprises a first
metallic tubular member 18 at the "proximal end" side and a second
metallic tubular member 19 having its distal end inserted into the central
hole 16 of the annular stepped portion 15 and its proximal end threadably
engaging the larger diameter portion 20 formed on the distal end of the
first tubular member 18. A metallic inner tube 21 is inserted into the
first tubular member 18 and has an outwardly extending flange 22 formed on
its intermediate outer surface. The flange 22 is slidably engaged at its
outer surface with the inner surface of the member 18 and the unflanged
intermediate outer surface portion of the inner tube 21 is adapted to be
slidably engaged with a flange 23 inwardly extending from the end of the
larger diameter portion 20 of the first tubular member 18. The distal end
of the inner tube 21 is screwed into a metallic hollow cylindrical
connection member 24 which is inserted into the second tubular member 19.
A metallic sleeve 25 is slidably inserted into the second tubular member
19. The "proximal end" half portion of the sleeve 25 is screwed on the
"distal end" portion of the connection member 24. An elastic sealing
member 26 is fixed to or pressed into the distal end side half portion of
the sleeve 25, so that the inner surface 25a of the sleeve 25 and the
outer surface 26a of the sealing member 26 closely contact each other. The
sealing member 26 is made of, for example, rubber or a flexible plastic
material and has a substantially H shape in longitudinal cross section. A
central aperture 27 is formed in the horizontal bar portion of said H
shape of the sealing member 26 and extends perpendicular to said
horizontal bar portion and has an inner diameter smaller than the outer
diameter of an elongated medical instrument 28, such as forceps, to be
inserted, as required, into the endoscope channel 10 through the inner
tube 21. With the medical instrument 28 inserted as shown in FIG. 2, the
sealing member 26 assures a fluid-tightness between the inner tube
assembly and the endoscope channel.
Provided between the proximal end portions of the first tubular member 18
and the inner tube 21 is a metallic stop ring 29 which is screwed on the
first tubular member 18. Between the flange 22 of the inner tube 21 and
the flange 23 of the first tubular member 18, a compression spring 30 is
wound around the inner tube 21. When the flange 22 of the inner tube 21 is
pressed by the compression spring 30, the inner tube 21, connection member
24, sleeve 25 and sealing member 26 are elastically urged as a unit toward
the proximal end of the control device. A flange 31 is formed on the
intermediate outer surface of the first tubular member 18. In the flange
31, a circumferentially spaced-apart passages 32 are formed. The outer
surface of the flange 31 is contacted by a reduced diameter surface 33 of
the "proximal end" portion of the hollow cylindrical member 14. The flange
31 coacts with an annular stepped portion 15 to hold the inner tube
assembly 12 in a concentric relation to the hollow cylindrical member 14.
A hollow cylindrical air chamber 34 is defined between the outer surface
of the tubular members 18, 19 (i.e. the outer surface of the inner
assembly) and the inner surface 17 of the hollow cylindrical member 14.
The chamber 34 communicates with the endoscope channel 10 through a hole
35 formed in that "distal end" portion of the second tubular member 19
which is located close to the sealing member 26. The chamber 34 also
communicates with a suction pipe 36 extending from the hollow cylindrical
member 14 and having its free end connected to a suction device (not
shown).
A mounting ring 37 has a disc portion 38 provided at the substantially
middle portion thereof and engaged with a shoulder 39 provided between the
reduced diameter portion 33 and the unreduced portion of the hollow
cylindrical member 14. The ring 37 has a first section at the "distal end"
side and a second section at the "proximal end" section with the disc
portion 38 in the middle. The first section of the ring 37 is screwed on a
flange 40 formed on the proximal end portion of the mounting tube 13 and
the second section of the ring 37 has the distal end portion of a
connector 41 inserted thereinto. The connector 41 is screwed over the
reduced diameter portion 33 of the hollow cylindrical member 14. In
consequence, the hollow cylindrical member 14 is fixed by the ring 37 and
connector 41 to the mounting tube 13.
In FIGS. 2 to 5, a cap 42 made of a flexible material such as rubber or
flexible plastic takes a form of a saddle in a longitudinal cross section
and oval shape in the plan view, having an overhanging portion 43. The cap
42 includes a substantially cylindrical communication chamber 44 having an
inner diameter substantially equal to the outer diameter of a flange 45
formed on the proximal end of the connector 41, a first air inlet 46 into
which the proximal end of the first tubular member 18 is inserted, and a
second air inlet 47 provided in the overhanging portion 43 thereof and
communicating with the chamber 44. The distal end of the cap 42 is
elastically pressed against the outer surface of the connector 41 clear of
the flange 45 of the connector 41. At the inlet 46, the cap 42 closely
contacts the proximal end portion of the first tubular member 18 and the
stop ring 29 with a flange 48 on the outer lateral surface of the stop
ring 29 fitted in an annular groove 49 in the inner wall of the air inlet
46. Thus, the cap 42 is sealingly provided on the proximal end of the
control device except for the air inlets 46, 47. The size and spacing of
both the air inlets 46, 47 are such that the air inlets 46 and 47 can be
positively blocked by a finger cushion 50.
The operation of the suction control device will now be described below.
Where a medical instrument 28 such as a forceps 28 is not inserted into the
control device, let both the air inlets 46 and 47 be blocked by the finger
cushion 50. Then, a negative pressure is built up by the suction device in
the channel 10 which communicates with the air chamber 34 through the hole
35. As a result, mucus and dirty substance are sucked out of the body
cavity of the human being. Since both the air inlets 46 and 47 are
arranged adjacent to each other, they can be advantageously blocked
simultaneously by the cushion of a single finger such as an index finger.
As the cap 42 is made of a flexible material, the air inlets 46 and 47 can
be completely blocked by the finger cushion, thereby preventing leakage of
air. Suppose that the inclination angle of the finger with respect to the
cap 42 varies, as shown in FIGS. 4 and 5. Even in this case, the
deformable overhanging portion 43 can be bent according to the inclination
angle to thereby block the air inlets 46, 47 in an airtight relation.
Now suppose that the medical instrument 28, such as forceps, are inserted
through the first air inlet 46. Since, in this case, the inner surface of
the central hole 27 sealingly contacts the outer surface of the instrument
28, no air is introduced through the first air inlet 46 into the channel
10 and thus a suction operation can be effected only by blocking the
second air inlet 47 by means of the finger cushion 50.
Where an injecting apparatus is employed, the proximal end of the inner
tube 21 is pressed by the forward end of the injecting apparatus so that
the inner tube assembly 12 is lowered until the outer surface of the
sleeve 25 blocks the hole 35 in the second tubular member 19. Then,
material to be injected is pushed out from the injecting apparatus into
the human body cavity through the suction control device 11 and the
channel 10. Since the hole 35 is blocked by the sleeve 25 in this case,
the material to be injected does not flow from the central bore defined by
the distal end side inner surface of the second tubular member 19 into the
chamber 34.
In an embodiment shown in FIG. 6 a stop ring 29 includes a flange 48 having
external screw threads 51 which engage internal screw threads 52 provided
on the inner annular recessed wall of a first air inlet 46. In this
arrangement a cap 42 can be attached to a stop ring 29 as in the case of
the embodiment of FIGS. 2, 4 and 5 in which a snap engagement is used. A
radially outwardly extending flange 53 is integrally formed on the distal
end of a second tubular member 19. The outer surface of the flange 53 is
slidably fitted in the increased inner surface of a hollow cylindrical
member 14. A plurality of passages 54 are formed in the flange 53 at its
circumferential intervals. The passages 54 correspond to the hole 35 of
the preceding embodiment.
In an embodiment shown in FIG. 7, flanges 54 and 55 are provided on the
proximal ends of a mounting tube 13 and hollow cylindrical member 14,
respectively. The flanges 54 and 55 make a snap engagement with
corresponding annular grooves 56 and 57 in a cap 42, respectively. In this
embodiment, the cap 42 can be sealingly mounted directly on an outer tube
assembly 11 and there is no need for a mounting ring and connector as used
in the preceding embodiment. This assures a simpler construction.
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