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BACKGROUND OF THE INVENTION
This invention relates to air and water supplying devices for endoscopes,
and more particularly to an air and water supplying device capable of
discharge the water left in a water supplying path connected between a
cleaning water storing tank and an endoscope and in a water supplying tube
within the endoscope.
An endoscope, especially an endoscope for examining the digestive organs,
is used to observe a portion of the body cavity through the window at the
top end part of a flexible elongated pipe of the endoscope inserted into
the body cavity. It is necessary to suitably inflate the portion to be
examined by supplying air in order to provide an observing distance
between the body portion to be examined and the top end part of the
endoscope. Furthermore, a supply of water must be provided at the portion
to be examined in order to clean the lens in the window provided at the
top end part of the endoscope, or to remove dirt from the window, or to
clean the portion to be observed.
For this purpose, the endoscope of this type is provided with an air and
water supplying mechanism in which an air supplying tube and a water
supplying tube connected to the manual operating section of the endoscope
are connected through a supply air and water switching valve mechanism to
an air and water supplying tube. The supply tube extends through the
flexible pipe of the endoscope to the top end part so that air or water
can be suitably supplied to the portion to be examined while the endoscope
is being operated.
If the use of such a conventional endoscope is suspended immediately after
water has been supplied hereto, the cleaning water is left in the water
supplying path of the water supplying system thereof after the
examination. It is very difficult to remove the water left in the water
supplying tube which extends from the water storing tank to the endoscope.
The end portion of the air and water supplying tube opened at the top end
of the endoscope is contaminated by the water which is caused to flow
backwardly into the tube by the internal pressure of the body.
Furthermore, the water left in the water supplying system is liable to be
spoiled. Accordingly, it is not sanitary to use the endoscope again with
any water remaining in the water supplying system. The water supplying
system is made up of plastic tubes. Because of the water absorbing
characteristic of the plastic tube and the corrosion of the connections of
the water supplying system, water may also leak out of the water supplying
system.
In order to observe a portion of the body cavity to be examined with an
endoscope, it is necessary to inflate the portion to be examined to a
certain extent. For this purpose, the air pump is provided for the
endoscope. The air supplying pressure of the air pump is relatively high,
because it is utilized also for supplying water to clean the observing
window of the endoscope.
With a conventional air supplying means, the period of time during which
air is supplied into the body cavity by the air pump is controlled to
adjust the quantity of air supplied into the body cavity. However, in such
an air supplying quantity controlling method, air is supplied under a
pressure much higher than the pressure which a portion of the body cavity
to be examined can withstand. Therefore, the excessively high pressure may
cause extreme discomfort to a patient and may rupture the body cavity.
Depending on portions of the body cavities to be examined such as the
stomach, the esophagus and the duodenum, the necessary quantity of air to
be supplied thereinto is different. However, in conventional methods, the
same quantity of air is supplied thereinto. As a result, the observing
conditions of these portions having different conditions of walls thereof
are varied, and the images formed by the endoscope are therefore varied,
which may result in errors in the diagnoses.
In the diagnosis by observing a portion to be examined with an endoscope
for a correct diagnosis it is essential to variously change the condition
of expansion of the portion to dynamically observe it. However, with air
supplying means of the conventional device, it is very difficult to
control the air supplying quantity for dynamically observing the
conditions of expansion of the portion to be examined.
The operation of an endoscope is carried out by delivery of cleaning water
to a portion of the body cavity to be examined to remove mucus, etc. from
the observing window of the endoscope or to clean the portion to be
examined so that the portion to be examined can be sufficiently observed.
The cleaning water used in this operation and the mucus in the body cavity
should be forcibly discharged out of the body by using a suction
mechanism.
For this purpose, heretofore, the suctions mechanism of this type comprises
a suction pump which is operated by a power device and is connected to a
suction pipe opened in the top end part of the endoscope. The suction
operation of the suction mechanism is carried out intermittently during
observation. Since the suction pump cannot start instantaneously, the
power device is maintained in operation during the observation so that the
suction pump operates instantaneously to meet the requirement of suction.
During the ordinary operating time, the suction pressure of the suction
pump is reduced or eliminated by suction air from an air passing pipe
which is opened in the finger placing surface of a piston protruding from
the manual operating section body of the endoscope. When suction is
required, the finger is placed on the finger placing surface of the piston
to depress the latter. In this operation, the air passing pipe opened in
the finger placing surface is closed by the finger, and therefore the
suction pressure of the suction pump is increased. As a result, the
cleaning water or the like is discharged through the sucking pipe.
The conventional device as described above is advantageous in that the
suction is effected instantaneously merely by placing the finger on the
top of the piston. However, it is still disadvantageous for the following
reasons. If, during the operation of the endoscope, the operator is
enthusiastic for the observation or the operation of the endoscope, he may
inadvertently place his finger on the top of the piston to close the air
passing pipe to unnecessarily suck out matter in the body cavity.
Furthermore, in order to avoid this unnecessary suction, he has to keep
his finger off the top of the piston intentionally, which leads to
fatigue.
As mentioned, in observing for instance a portion of the stomach with an
endoscope, it is necessary to send air thereinto to provide an observing
distance between the endoscope and the portion to be examined, or to
inflate the body cavity. With an endoscope provided with the
above-described prior art air supplying device and suction device, the
conditions of a portion to be examined can be dynamically observed during
the process in which, after air is supplied into the body cavity by the
air supplying device to excessively expand the portion to be examined and
the air is gradually removed from the body cavity by the suction device.
The conventional suction device is operated by closing the end of the air
passing pipe with the finger, but it is difficult to suitably adjust the
degree of suction with the sensual operation of the finger. Thus, the
conventional device is not practical.
SUMMARY OF THE INVENTION
Accordingly, an object of this invention is to provide an air and water
supplying device in which after the use of an endoscope, the water left in
the water supplying system can be positively discharged by the utilization
of compressed air pressure used to supply air to the endoscope.
Another object of this invention is to provide an endoscope that is
sanitary and easy to use.
Yet another object of this invention is to provide a switching device in
which when no air is supplied through an air supplying conduit pipe
communications to the top end part of an endoscope, the air supplying
conduit pipe is disconnected from an air discharging path, and the outer
end of the conduit pipe is maintained closed, and in supplying water, a
compressed air discharging path is disconnected from the air supplying
system.
Still another object of this invention is to provide air and water
supplying device for an endoscope, in which in supplying air into the body
cavity, the air supplying pressure and the air supplying quantity per
unitary time are suitably controlled.
A further object of this invention is to provide a device to protect a
patient from danger due to an excessively high pressure and to dynamically
observe the conditions of expansion of a portion of the body cavity to be
examined.
An additional object of this invention is to provide a suction device for
an endoscope, in which instead of closing the end of the air passing pipe
with the finger, the suction is controlled by the depression of a piston
having excellent operating stability.
Another additional object of this invention is to provide a suction device
where the degree of suction is readily adjusted by the depression of the
piston.
These and other objects of this invention will become apparent from the
drawings and the description of the preferred embodiments that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an explanatory diagram showing the arrangement of a first example
of an air and water supplying device according to this invention;
FIG. 2 is also an explanatory diagram showing the arrangement of a second
example of the air and water supplying device according to the invention;
FIG. 3 is an explanatory diagram showing the arrangement of a third example
of a device for switching air and water supplying operations in an
endoscope according to this invention;
FIG. 4 is a vertical sectional view showing the essential components of a
first example of the air-water valve according to the invention;
FIG. 5 is a vertical sectional view showing the essential components of a
second example of the air-water valve according to the invention;
FIG. 6 is a vertical sectional view showing the essential components of a
third example of an air and water supplying device according to this
invention;
FIGS. 7 through 10 are sectional views taken along line A--A in FIG. 6,
showing the conditions of adjustment of outlets formed in a piston shown
in FIG. 6;
FIG. 11 is a sectional view taken along line B--B in FIG. 6, showing an
adjustment position holding mechanism;
FIG. 12 is a graphical representation indicating the characteristic curves
representative of adjusted air supplying pressures and air supplying
quantities;
FIG. 13 is a side view showing an example of a suction valve according to
this invention incorporated in the manual operating section of an
endoscope;
FIG. 14 is a sectional side view taken along line A--A in FIG. 1, showing
the valve according to the invention; and
FIGS. 15A and 15B are an explanatory diagrams showing different examples of
one end of an air sucking pipe of the device according to the invention,
which is opened in the wall of the cylinder.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
This invention will be described with reference to its preferred
embodiments shown in the accompanying drawings. FIG. 1 is an explanatory
diagram showing the arrangement of one example of an air and water
supplying device according to the invention. As shown in FIG. 1, an air
pump 1 is connected through an air supplying tube 4 to a cleaning water
storing tank 2 and an endoscope 3. A supply path switching valve 5 is
interposed in the tube 4 between elements 4 and 4'. On the other hand, the
water storing tank 2 is connected through a water supplying tube 6 to the
endoscope 3.
The supply path switching valve 5 comprises: a cylinder housing 5a secured
to the wall of the housing of the air pump 1, and a piston 5c, fitted in
the housing 5a in such a manner that it is energized outwardly by the
elastic force of a spring 5b. The housing 5a has a supply air receiving
inlet 7, and first and second supply air delivering outlets 8 and 9 in
association with the inlet 7. The piston 5c has a first circumferential
groove 10 which communicates the inlet 7 with the first outlet 8 when the
piston is moved outward of the cylinder and a second circumferential
groove 11 which communicates the inlet 7 with the second outlet 9 when the
piston is moved to an inward position.
The second supply air delivering outlet 9 is connected to the middle
portion of the water supplying tube 6 through a check valve 12 and an air
supplying tube 13 for discharging water. In FIG. 1, the following other
elements are shown. Reference numeral 14 designates the supply air
receiving inlet of the water storing tank 2 and reference numeral 15 is an
air supplying tube opened in the tank 2. The water supplying outlet of the
tank 2 is designated 16 and is coupled to a water pumping-up tube 17 that
opens in the tank 2. The supply air receiving inlet 18 of the endoscope 3
and the supply water receiving inlet 19 of the endoscope 3 are coupled to
a supply air and water switching valve 20. Reference numeral 21 designates
an air and water supplying tube coupled to the valve 20.
FIG. 2 shows a second example of the air and water supplying device
according to the invention, in which those components which have been
previously described with reference to FIG. 1 have therefore been
similarly numbered. The water pumping-up tube 17 opened in the tank 2 is
provided with a branch tube 17a in the upper portion of the tank 2 where
air exists (hereinafter referred to as "a hollow part" when applicable),
in such a manner that the branch tube 17a is opened or closed in the
hollow part of the tank by operating a valve 5.
In the first example of the air and water supplying device constructed as
shown in FIG. 1, under the normal operating condition the piston 5c of the
supply path switching valve 5 is extended outwardly as shown in FIG. 1.
Under this condition, the compressed air in the pump 1 is delivered to the
endoscope 3 and the tank 2 through the first air supplying tube 4, the
supply air receiving inlet 7, the circumferential groove 10, the supply
air delivering outlet 4', and the second air supplying tube 4" which is
connected to the endoscope and the tank. If, in this case, the supply air
and water switching valve in the endoscope 3 is in the air supplying
state; that is, the water supplying side thereof is closed, then under the
condition that the delivery of air to the tank 2 is blocked, the
compressed air from the air pump 1 is delivered to the top end part of the
endoscope through the air and water supplying tube 21.
If, under this condition, the air supplying side is closed and the water
supplying side is opened by operating the supply air and water switching
valve 20, then the compressed air from the air pump 1 is delivered into
the water storing tank 2. As a result, a pressure is created in the tank
2, whereby the water in the tank 2 is pressurized. Accordingly, the water
is forcibly delivered through the water pumping-up tube 17, the water
supplying tube 6 and the air and water supplying tube 21 to the end
portion of the endoscope.
After a portion of the body cavity has been examined with the endoscope
with the aid of the above-described air and water supplying operation, the
piston 5c of the supply path switching valve 5 is depressed against the
elastic force of the spring 5b. In this operation, as the piston 5c is
moved inwardly, the supply air receiving inlet 7 communicates with the
second supply air delivery outlet 9 through the circumferential groove 11,
so that the compressed air in the air pump 1 is delivered through the air
supplying tube 13 for discharging water to the water supplying tube 6. As
a result, the water left in the water supplying system including the air
and water supplying tube is discharged from the top end part of the
endoscope through the tube 6. The supply air and water switching valve 20
has been placed in the water supplying state during this operation.
In the second example of the air and water supplying device shown in FIG.
2, the air and water supplying operation can be performed in a similar
manner to the first example shown in FIG. 1, with the branch tube 17a in
the water storing tank 2 closed by operating the valve 5. If the branch
tube 17a is opened in the hollow part of the water storing tank 2 by
operating the valve 5 after the examination of a portion of the body
cavity with the endoscope, then the compressed air delivered into the
water storing tank 2 from the air pump 1 is delivered to the water
pumping-up tube 17. As a result, the water left in the water supplying
system including the tube 17 is discharged from the tip end of the air and
water supplying tube in the top end part of the endoscope through the
supply air and water switching valve 20.
As is apparent from the above description, the air and water supplying
device according to the invention is a simple mechanism comprising the air
supplying path which is connected by switching means to the external path
of the endoscope which is included in the water supplying system of the
air and water supplying mechanism of the endoscope. The water left in the
water supplying system can be positively discharged by the use of the
supplied air after a portion of the body cavity has been examined with the
endoscope. The supply path switching valve 5 and the valve 20 in the
device according to these embodiments and the arrangement of the water
supplying system can be changed and modified without departing the
inventive concept of the invention.
In the embodiments of FIGS. 1 and 2 the pump 1 is employed for pressurizing
the cleaning water to allow it to jet out of the top end part of the
endoscope. Also, the switch 20 for the air supplying and the water
supplying operation is provided in the manual operating section of the
endoscope.
The switching device of this type is designed so that an air passing pipe
for discharging the compressed air which is supplied through an air
supplying pipe is provided, and when the outlet of the air passing pipe is
closed, the compressed air is delivered into a pipe having the inner end
at the top end part of the endoscope and the outer end communicating with
the compressed air discharging path. Accordingly, when the air is being
discharged through the air passing pipe, the pipe system is left open,
which may cause the air in the body cavity to flow through the inner end
of the pipe at the end portion of the endoscope or mucus in the body
cavity to flow backwardly through the pipe.
In order to prevent this difficulty, the check valve 12 may be connected to
the pipe system. However, this method is undesirable for sanitation,
because dirt or the like is caught by the check valve, which makes it
difficult to clean the pipe system.
Also, in such a device a pipe extending to the top end part of an endoscope
is opened in a compressed air discharging path as described above, and if
the operator, being ethusiastic for the observation, or the operation of
the forceps, carelessly closes the outlet of the air passing pipe with his
finger, then air is unintentionally delivered into the body cavity.
Furthermore, with the device, water is supplied to the endoscope by
utilizing the pressure of compressed air with the outlet of the air
passing pipe with the finger. Therefore, the outlet must be maintained
closed with the finger throughout the water supplying operation, that is,
the operator must pay attention to finger operation also, which may
adversely affect the operation of the endoscope.
To overcome these difficulties a third embodiment of this invention are
shown in FIGS. 3-12 which detail three examples of the air-water switching
valve 20. In these embodiments the air valve switching mechanism 5 is
eliminated and all control functions take place at the endoscope handle.
In FIGS. 6-12 the valve is used for a metering function to adjust air
pressure supplied to the body cavity.
FIG. 3 is an explanatory diagram showing the arrangement of a third
embodiment of the invention. A cylinder 20 is arranged in the manual
operating section body 3 of an endoscope. A piston assembly 30 is slidably
fitted in the cylinder 20 in such a manner the top part 30a of the piston
assembly is protruded from the cylinder 20 to depress the piston assembly
30. An air supplying pipe 4, a water supplying pipe 6, and an air and or
water supplying conduit pipe 21 are connected to the cylinder 2. The pipe
21 extends to the top end part 60 of the endoscope. The other end of the
air supplying pipe 4 is connected to an air pump 1 provided separately.
The branch pipe 4a of the pipe 4 is inserted into a sealed cleaning water
container 2. The other end of the water supplying pipe 6 is inserted into
the cleaning water R in the container 1.
FIG. 4 is a vertical sectional view of the essential components of the
first embodiment of the air-water valve according to the invention. The
cylinder 20 is screwed into the manual operating section body 3 to form
one unit. The air supplying pipe 4, the water supplying pipe 6 and the
conduit pipe 21 are connected to predetermined portions (described later)
of the wall of the cylinder, respectively. In this embodiment, the conduit
pipe 21 is used to supply air and for water.
The piston assembly 30 comprises: a first piston 31 having a hollow part
employed as an air passing pipe 80 for discharging compressed air, and a
second piston 32 fitted over the first piston 31. That is, the piston
assembly 30 is a dual concentric pipe. A spring 90 is disposed between the
two pistons 31 and 32. More specifically, a locking ring 100 is provided
at the lower end portion of the first piston 31 so that the second piston
32 is not removed from the first piston 31, under the action of the spring
9. That is, the first and second pistons are maintained in an ordinary
state as shown in FIG. 2.
A pin 120 extending from the second piston is slidably fitted in an
elongated groove 110 cut in the wall of the first piston 31, so that the
first and second pistons are not turned relative to each other.
A finger placing part 31a serving as the outlet of the air passing pipe 80
is mounted on the top of the first piston 31. A side port 130 is formed in
the lower portion of the first piston 31. The second piston 32 has a
collar 32a at the upper portion thereof. A retaining fitting 140 is
screwed into the body 3. A spring 90a having a relatively strong expanding
force is interposed between the collar 32a and the retaining fitting 140.
In this assembled condition, the second piston 32 is fitted into the
above-described cylinder 20. A circumferential groove 150 and a small hole
150a connected thereto are formed in the wall of the second piston at a
level coinciding with the piston of the end of the conduit pipe 21, which
is opened in the wall of the cylinder when the lower end of the retaining
fitting 140 abuts against the engaging shoulder 32b of the second piston
32.
A portion of the middle part of the second piston is removed to form a
chamber 160 between the inner wall of the cylinder and the second piston.
When the assembly of the two pistons 31 and 32 is inserted into the
cylinder 20, in the ordinary state another chamber 170 is formed between
the lower end of the assembly and the bottom of the cylinder 20.
The position of the end of the water supplying pipe 6, which is connection
to the wall of the cylinder, is determined so that the pipe 6 communicates
with the chamber 160. The end of the air supplying pipe 4, which is
connected to the wall of the cylinder, is at a distance l.sub.2 from the
lower end of the second piston 32. This distance l.sub.2 is the distance
between the collar 32a of the second piston and the upper end of the
retaining fitting 140. That is, it is the distance of movement of the
second piston 32. The distance l.sub.2 is employed for determining the
positions of the ends of the conduit pipe 7 and the water supplying pipe
6, which are connected to the cylinder as shown in FIG. 4. The distance
l.sub.1 between the lower surface of the finger placing part 31a of the
first piston 31 and the collar 32a, that is, the relative movement
distance of the first and second pistons 31 and 32 is employed to
determine the positions of the side hole 130 of the first piston 31 and
the small hole 150a of the second piston 32.
In FIG. 4, reference character 180 designates water-tight "O"-rings for
purposes of sealing the unit.
In FIG. 5 shows a second example of the air-water valve according to the
invention, in which those components which are similar in function to
those described with reference to FIG. 4 are therefore similarly numbered.
In this embodiment, the piston section 30 is a single piston 33. A conduit
pipe 21 connected to the cylinder 2 is used to supply air only, and a
conduit pipe 190 for supplying water only is connected to the cylinder 20.
A finger placing part 33a serving also as the collar described with
reference to FIG. 4 is mounted on the top of the piston 33. The distance
m.sub.1 between the lower surface of the finger placing part 33a and a
spring engaging member 220, that is, the first depression distance of the
piston 33, is employed to determine the position of the end of a conduit
pipe 21 supplying only air. The distance m.sub.2 between the end of the
wall of the finger placing part 33a and the locking shoulder of a
retaining fitting 140, that is, the maximum movement distance of the
piston 33 is employed to determine the positions of the ends of the air
supplying pipe 4, the water supplying pipe 6, and the conduit pipes 21 and
190. In FIG. 5, reference character 33b designates a locking shoulder of
the piston 33, which abuts against the lower surface of the retaining
fitting 140.
Assembly of the devices described above can be achieved as follows: First,
the cylinder 20 is screwed into the manual operating section body 3. Then,
the pipes (4, 5, 21 and 190) are connected to the wall of the cylinder.
The piston assembly 30 obtained by assembling its various components is
inserted into the cylinder 20 and is secured fixedly by tightening the
retaining fitting 140. Accordingly, if necessary, the piston assembly 30
can be readily removed from the cylinder 20, and accordingly from the body
3, by removing the retaining fitting 140.
In operation, when the air pump 1 is operated, air is supplied through the
air supplying pipe 4 into the chamber 170 in the cylinder 30 and through
the branch pipe 4a into the sealed container 2. However, since the water
supplying pipe 6 extending from the container 2 is connected to the
independent chamber 160 in the cylinder 20 (in the embodiment shown in
FIG. 4) or it is closed by the piston 33 (in the embodiment shown in FIG.
5), therefore no air supplying operation is effecutated.
With respect to FIG. 4, the air supplied into the chamber 170 is discharged
out of the outlet formed in the top part of the piston assembly 30 through
the air passing pipe 80. In this case, the end of the conduit pipe 21
communicating with the top end part of the endoscope coincides with the
circumferential groove 150 of the second piston 32, but the small hole
150a connected to the circumferential groove 150 is closed by the first
piston 31. Therefore the end of the conduit pipe 21 is maintained closed.
Then, in order to supply air into the endoscope, the finger is placed on
the finger placing part 31a while closing the outlet, and the finger
placing part 31a is depressed by the finger. As a result, the first piston
31 is lowered, against the elastic force of the weak spring 90 disposed
between the first and second pistons 31 and 32, the distance l.sub.1 until
the lower surface of the finger placing part 31a abuts against the upper
surface of the collar 32a. As a result, the side hole 130 of the first
piston 31 coincides with the small hole 150a of the second piston 32, so
that the conduit pipe 21 is in communication with the air passing pipe 80.
Accordingly, the air supplied through the air supplying pipe 4 is
delivered through the conduit pipe 21 and is jetted out of the top end
part 60 of the endoscope, since the outlet of the air passing pipe 80 has
been closed by the finger.
When the piston assembly 30 is further depressed, then the second piston 32
integral with the first piston 31 is lowered, against the elastic force of
the strong spring 90a, the distance l.sub.2 until the lower surface of the
collar 32a abuts against the upper surface of the retaining fitting 140.
As a result, the chamber 160 is also lowered, and accordingly the water
supplying pipe 6 is in communication through the chamber 160 with the
conduit pipe 21, while the air supplying pipe 4 is closed by the second
piston 32.
Accordingly, compressed air is delivered from the air pump 1 through the
branch pipe 4a into the sealed container 1. As a result the pressure
created in the container 1 is applied to the cleaning water R therein, so
that the cleaning water is delivered through the air supplying pipe 6 and
the conduit pipe 21 communicating therewith to the top end part 60 of the
endoscope, thus being ejected out of it.
When the finger is removed from the piston assembly 30, the first and
second pistons 31 and 32 are returned to their initial positions by the
elastic forces of the springs 90 and 90a to suspend the above-described
operation.
In the case of the fourth embodiment shown in FIG. 5, by the first
depression of the piston 33, the piston 33 is moved the distance m.sub.1
against the elastic force of the weak spring 90. Under this condition, the
conduit pipe 21 for supplying air only communicates through the
circumferential groove 150 to the air passing pipe 80. In this case, since
the outlet in the finger placing part has been closed by the finger, the
air supplied through the air supplying pipe 4 is ejected out of the top
end part 60 of the endoscope.
When the piston 33 is further depressed the distance m.sub.2, then
similarly as in the third embodiment shown in FIG. 4, the conduit pipe 190
for only supplying air communicates through the chamber 160 with the air
supplying pipe, so that water is delivered to the top end part 60 of the
endoscope.
As is apparent from the above description, with respect to the means of
switching the water and air supplying operations in the device according
to the invention, in the ordinary state thereof, i.e., before the valve is
operated, the ends of the conduits connected to the cylinder are closed by
the piston. Therefore, it is possible to prevent air or dirt from flowing
backwardly into the conduits due to the pressure in the body cavity. Thus,
the conditions of observation can be maintained in a stable environment.
The amount of air supplied into the body cavity is limited to a minimum
value necessary for the observation, which relieves discomfort to the
patient.
The device itself is not contaminated by dirt or the like, that is, it is
kept sanitary, which is effective to protect a patient from infection. In
the ordinary state in which no air and water supplying operations are
carried out, the conduits for supplying air and water are closed.
Therefore, even if the operator closes the outlet formed in the top part
of the piston carelessly during the observation, no air is supplied to the
top end part of the endoscope. Hence according to these examples the
device is excellent in terms of security of operation. Furthermore, in the
water supplying operation in which the piston is depressed, the air
supplying pipe connected to the cylinder is closed by the piston.
Therefore, in this case, it is unnecessary to continuously close the
aforementioned outlet of the air passing pipe with the finger.
Accordingly, the burden on the operator to pay attention to the operation
of the finger can be relieved.
Referring now to FIGS. 6-11 a third example of an air-water valve is shown
in which the air pressure can be precisely controlled.
FIG. 6 is a vertical sectional view showing the essential components of an
air and water supplying device according to the third example of this
invention. A cylinder 20 is fixedly screwed into the manual operating
section 3 of an endoscope. A piston 30 is slidably fitted into the
cylinder 20 in such a manner that it can be readily depressed downwardly
but it cannot be removed from the cylinder by means of a retaining fitting
140. An annular collar 160 retained by a locking washer 250 is slidably
fitted over the piston 30. A weak elastic spring 90a is interposed between
the collar 260 and the shoulder of the retaining fitting 140, and a strong
elastic spring 90 is interposed through the locking ring of an adjusting
member (described later) between the collar 260 and the locking edge 30a
of the piston 30.
A mechanism for preventing the rotation of the piston 30 is provided
between the cylinder 20 and the piston 30. It comprises, a pin 190
extending from the cylinder 20 into a long groove 30b cut axially in the
lower portion of the piston 30. A conduit pipe 21 communicating with the
top end part 60 of the endoscope, an air supplying pipe 4 connected to an
air pump 1 and a water supplying pipe 6 connected to a water storing tank
2 are connected to the side wall of the cylinder 20. The positions of
connection of the conduit pipe 21, the air supplying pipe 4 and the water
supplying pipe 6 are as follows: The air supplying pipe 21 is connected to
a point on the side wall of the cylinder, which is below the lower end of
the piston 30 when the piston 30 is positioned as indicated in FIG. 6 by
the elastic forces of the two springs 90 and 90a and which is above the
lower end (indicated by the dotted line) of the piston when the piston 30
is depressed. The air supplying pipe 6 is connected to the side wall so
that it is at all times in communication with a chamber 160 which is
formed by the inner wall of the cylinder 20 and a recess cut in a portion
of the outer wall of the piston 30. The conduit pipe 21 is connected to a
point on the side wall of the cylinder, which coincides with a side hole
150 cut in the piston 30 when the piston 30 is slightly depressed, and
communicates with the above-described chamber 160 when the piston 30 is
further depressed. A through-hole, or an air discharging path 80, is cut
along the axis of the piston 30. Thus, the piston 30 is utilized as an air
discharging pipe. Outlets 27a, 27b, and 27c are formed radially in the
upper portion of the piston 30 so that these outlets communicate with the
air discharging path 80 in the piston 30 (cf. FIGS. 7 through 10).
Furthermore, an adjusting member 280 is rotatably fitted over the top end
portion of the piston 30 by being positioned by a finger placing member
31a and the locking ring 280a. The adjusting member 280 as shown in FIGS.
7 through 10, has grooves 290a, 290b, 290c and 290d varying in
circumferential length which are cut in its inner peripheral wall adjacent
to the piston 30, and through-holes 220a, 220b, 220c and 220d
communicating respectively with the grooves 290a, 290b, 290c and 290d,
which are cut in the outer peripheral wall of the cylinder 20 at a level
equal to that of the above-described outlets 27a through 27c.
The piston 30 has engaging grooves 221a, 221b, 221c and 221d in the outer
wall (FIG. 11) which are positioned in association with the positions of
the outlets 27a through 27c and the grooves 290a through 290d. A threaded
pipe 24 is screwed in the wall of the adjusting member 280, and a click
ball 23 is placed in the threaded pipe and is energized by a spring 22 so
that it can engage with the above-described engaging grooves 221a through
221d. Furthermore, an engaging pin 26 is screwed in the wall of the
adjusting member 280 in such a manner that its end portion protrudes in a
rotation regulating groove 25 cut in the outer wall of the piston 30.
In FIG. 6, reference character 240 designates abutting pins protruded from
the retaining fitting 140 toward the abutting shoulder of the piston 30,
and reference numeral 180 designates "O"-rings fitted in the piston 30.
FIG. 12 is a graphical representation indicating characteristic curves
L.sub.1 and L.sub.2 representative of the relationships between the area D
of the outlet of the air discharging pipe of the device according to this
invention and the air supplying pressure P, and between the area D and the
air supplying quantity Q.
First, the device is in a normal state as shown in FIG. 6. That is, the
piston 30 is at the upper position where it is pushed upwardly by the
elastic forces of the springs 90 and 90a but is retained by the abutting
pins 240 of the retaining fitting 140. In this condition, air is
introduced into the cylinder 20 through the air supplying pipe 4 by the
operation of the air pump 1. However, since the conduit pipe 21 is closed
by the piston 30, the air is not delivered to the top end part 60 of the
endoscope. Furthermore, the water supplying pipe 6 communicates with the
independent chamber 160, but not with the conduit pipe 21, and therefore
no air or water is supplied to the top end part 60 of the endoscope.
If, under this condition, the piston 30 is depressed, first the piston 30
is lowered against the elastic force of the weak spring 90a while
compressing the latter. This depression is continued smoothly until the
annular collar 260 supporting one end of the spring abuts against the
shoulder of the retaining fitting 240, i.e., the depressing finger feels
the reaction which is caused when the succeeding depression causes the
annular collar 260 to compress the strong spring 90.
In this first step of depressing the piston, the air supplying pipe is
maintained in communication with the air discharging path 80 and the
conduit pipe 21 coincides with the side hole 150 of the piston 30.
Therefore, the air delivered through the air supplying pipe 4 is
introduced into the conduit pipe 21 and is delivered to the top end
portion 60 of the endoscope.
In this case, the rotation of the piston 30 is prevented by the pin 190
inserted in the wall of the cylinder 20 | | |
