U.S. patent number 3,578,884 [Application Number 04/823,086] was granted by the patent office on 1971-05-18 for oral hygiene apparatus.
This patent grant is currently assigned to General Electric Company. Invention is credited to Chester F. Jacobson.
United States Patent |
3,578,884 |
Jacobson |
May 18, 1971 |
**Please see images for:
( Certificate of Correction ) ** |
ORAL HYGIENE APPARATUS
Abstract
The disclosure herein concerns an improvement for oral hygiene
apparatus of the variable pressure pulsed liquid jet type. The oral
hygiene apparatus has a single control that regulates the amount of
liquid pressure and actuates the motor switch only when the
pressure setting is on low, thus permitting the use of a motor that
has a lower starting than run torque, such as a shaded pole motor,
with a minimum starting torque capacity.
Inventors: |
Jacobson; Chester F. (Scotia,
NY) |
Assignee: |
General Electric Company
(N/A)
|
Family
ID: |
25237748 |
Appl.
No.: |
04/823,086 |
Filed: |
May 8, 1969 |
Current U.S.
Class: |
417/317;
601/162 |
Current CPC
Class: |
F04B
53/10 (20130101); A61C 1/0092 (20130101) |
Current International
Class: |
A61C
1/00 (20060101); F04B 53/10 (20060101); F04d
021/02 (); A61h 009/00 () |
Field of
Search: |
;103/41,38,40,42,25,35
;128/66 ;417/317 ;230/28,30,31,24 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Walker; Robert M.
Claims
I claim:
1. In an oral hygiene apparatus of the variable pressure liquid jet
type, the improvement comprising:
a. a liquid pump assembly having a pumping piston;
b. a motor having a lower starting than run torque;
c. motor switch means for energizing said motor;
d. drive means connecting said motor and piston; and
e. a single control means that variably adjusts the liquid pressure
output of the pump from low to high and actuates the motor switch
only when said control means is adjusted for low-pressure liquid
discharge.
2. The improvement in oral hygiene apparatus in accordance with
claim 1, wherein the motor is of the shaded pole type and has a
starting torque capacity slightly in excess of the torque load
requirements of the apparatus when the control means is adjusted
for low-pressure liquid discharge.
3. The improvement in oral hygiene apparatus in accordance with
claim 1, wherein the motor switch means is of the plunger type that
is actuated to energize the motor when the plunger is extended, and
deactuated when the plunger is depressed.
4. The improvement in oral hygiene apparatus in accordance with
claim 3, wherein the control means includes a manually operated
control with a cam element that depresses the plunger in the off
position and releases the plunger when adjusted for low-pressure
liquid discharge.
5. In an oral hygiene apparatus of the variable pressure pulsed
liquid jet type, the improvement comprising:
a. a liquid pump assembly having a chamber, an intake port and an
outlet port for said chamber, a piston for applying pressure to
liquid in said chamber, and an adjustable valve for regulating the
amount of liquid pressure;
b. a shaded pole motor;
c. motor switch means for energizing said motor;
d. drive means connecting said motor and piston; and
e. control means including:
aa. a manually operated control that deactuates the motor switch in
the off position and actuates the motor switch at a low liquid
pressure position;
bb. means for adjusting said valve; and
cc. means connecting said manually operated control and said valve
adjusting means, whereby said valve is adjusted in response to
operation of said control.
6. The improvement in oral hygiene apparatus in accordance with
claim 5, wherein the motor switch is of the plunger type that is
actuated to energize the motor when the plunger is extended and
deactuated when the plunger is depressed, and the manually operated
control has a cam element that depresses the plunger in the off
position and releases the plunger at a low liquid pressure
position.
7. The improvement in oral hygiene apparatus in accordance with
claim 5, wherein the motor has a starting torque capacity slightly
in excess of the torque load requirements of the apparatus when the
control means is adjusted for liquid pressure.
8. The improvement in oral hygiene apparatus in accordance with
claim 5, wherein the valve is between the inlet port and outlet
port and the liquid pressure is adjusted by the valve controlling
the amount of liquid flowing past the valve into the inlet port
when the pressure is applied to the liquid in the chamber.
9. The improvement in oral hygiene apparatus in accordance with
claim 6, wherein the means for adjusting the valve is a screw that
is movable inwardly and outwardly of said chamber in response to
rotation.
Description
BACKGROUND OF THE INVENTION
This invention relates to oral hygiene apparatus of the liquid jet
type used for cleaning teeth and massaging the gum tissues.
Oral hygiene apparatus for producing a small jet of liquid
comprising pulses of liquid discharged at substantial velocity may
be used for cleaning the teeth and gums. The method of cleaning
teeth by a jet of liquid is particularly beneficial for users that
have intricate or fragile dental braces and appliances. One form of
apparatus for practicing this method of cleaning the teeth and gums
includes a pump with a reciprocating piston arranged in the pump
cylinder. To produce the jet of pulsating liquid, the piston
applies pressure during its forward stroke to liquid drawn into the
pump cylinder during the rearward stroke. The pump is provided with
a means of adjusting the amount or intensity of the liquid
pressure.
Oral hygiene apparatus of this type commonly has its own reservoir
for supplying the liquid used in the apparatus system. The
reservoir is filled with the desired liquid, such as water or an
oral cleansing solution, and is placed in such a manner that it
communicates with the pump, and the liquid is introduced into the
pump. During the forward stroke of the piston, the liquid leaves
the pump under pressure by means of a conduit that carries the
pulsating water to a hand nozzle for discharge from the apparatus
system. Such apparatus normally is designed so that the amount of
liquid pressure will be in the range of 20 to 90 p.s.i.
Oral hygiene apparatus used heretofore have a switch for starting
the apparatus by energizing the electric motor which drives the
pump piston. A separate control for the user to regulate the amount
of liquid pressure discharged from the apparatus system is also
provided. There is, therefore, an independent switch for energizing
the motor and a separate control for regulating the amount of
pressure, which control does not affect or actuate the switch. Such
an arrangement presents difficulties for two reasons. In the case
of oral hygiene apparatus of previous design, it often happened
that the apparatus was started by the user energizing the motor,
with the liquid pressure control inadvertently positioned on a
high-pressure setting. The result of such an occurrence in an
incompressible liquid system, as involved here, is that the motor
is prevented from obtaining its proper speed unless the motor
employed is one which has a starting torque of sufficient capacity
to overcome the load conditions of the apparatus when the pressure
setting is on high. If the motor is prevented from reaching its
proper speed, the life of the motor is detrimentally affected.
Oftentimes the motor will overhead and eventually burn out.
Moreover, from the standpoint of the user's comfort, even if a
motor of sufficient torque capacity is used, it is undesirable to
have the initial use of the oral hygiene apparatus set on the high
pressure setting.
By my invention, there is provided an improved oral hygiene
apparatus that has a control means that allows the use of a motor
with a lower starting than run torque with a minimum starting
torque capacity, and it also assures that the apparatus is started
at a low liquid pressure setting.
SUMMARY OF THE INVENTION
In accordance with this invention, there is provided oral hygiene
apparatus that includes a motor, liquid pump, and a control means
for the user to regulate the amount or intensity of the liquid
pressure discharged from the apparatus system. The oral hygiene
apparatus also includes a liquid reservoir for supplying the
necessary liquid to the apparatus system and a nozzle with
connecting conduit for directing the pulsating jet stream of liquid
into the user's mouth for cleaning the teeth and gums. The liquid
pressure is achieved by means of a pump assembly utilizing a
reciprocating piston within a cylinder or pressure chamber of the
pump that applies the necessary pressure to the liquid in the pump
chamber to produce a stream of pulsed jets of liquid that are
carried from the pump through a connecting conduit to the nozzle
and ultimately discharged from the apparatus system. The pressure
is regulated by a valve within the pump pressure chamber that is
controlled by screw means which may be turned clockwise or
counterclockwise to vary the position of the valve. A control knob
accessible to the user from outside the oral hygiene apparatus
housing may be manually moved, which in turn through linkage
connecting the knob and screw means regulates the amount of liquid
pressure by controlling the valve. The control knob also controls a
switch for energizing the electric motor. By having the motor
switch positioned such that it cannot be switched off or deactuated
without first adjusting the liquid pressure to the low setting
assures that when the apparatus is used the next time the motor
switch can only be actuated to energize the motor when the liquid
pressure setting is low. By this arrangement, I have found that an
electric motor that has a lower starting than run torque, such as a
shaded pole motor, with a minimum starting torque capacity may be
used effectively. The starting torque capacity of the motor need by
only slightly in excess of that necessary under normal operating
conditions to accommodate the apparatus load requirements when the
control means is adjusted for low pressure liquid discharge.
It is an object of this invention to provide an improved apparatus
for use in oral hygiene that produces a high velocity liquid jet
for cleaning the teeth and gums.
It is also an object of this invention to provide oral hygiene
apparatus with control means that may have the liquid pressure
regulated and the motor switch actuated to energize the motor only
when the control means is adjusted for low pressure liquid
discharge.
It is another object of this invention to provide an oral hygiene
apparatus of the pulsed water jet type that may utilize a motor
with a lower starting than run torque and in particular a shaded
pole motor of minimum starting torque capacity for the apparatus
load requirements
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of my oral hygiene apparatus with a
broken-away portion showing the control assembly.
FIG. 2 is an end elevation view of my oral hygiene apparatus with
the housing, reservoir, and base shown in section.
FIG. 3 is a partially sectioned perspective view of the liquid pump
assembly and control assembly.
FIG. 4 is the pressure chamber portion of the liquid pump assembly
shown in section and the pressure adjusting valve arrangement when
in the low-pressure position.
FIG. 5 is the pressure chamber portion of the liquid pump assembly
shown in section and the pressure adjusting valve arrangement when
in the high-pressure position.
FIG. 6 is a sectional view of the pump pressure chamber taken on
line 6-6 of FIG. 4.
FIG. 7 is a curve showing the relationship speed to torque of a
shaded pole motor.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, the apparatus illustrated in FIGS. 1
and 2 comprises a reservoir 10 placed on top of a housing 30 for a
motor pump assembly indicated generally at 11. The reservoir
provides a means of supplying liquid to the apparatus system. The
liquid may, of course, be any liquid the user desires, such as
water or an oral cleansing solution. The liquid is introduced into
the underlying pump assembly 24 by a conduit 23 leading from a
recess 27 in the housing 30 that is adapted to engage a boss 12 in
the bottom of the reservoir 10. The liquid from the reservoir 10
passes through an opening 28 in the boss 12 into the recess 27 then
through an exit opening 29 in the sidewall thereof into conduit 23
and into the pump assembly 24. A flexible plastic discharge tube 14
carries the liquid under pressure from the pump to a hand nozzle
13. The tube 14 is secured to the hand nozzle 13 by a coupling 17.
The hand nozzle 13 is designed to be manipulated by hand to direct
the high velocity liquid jet discharged from the nozzle 13 against
the teeth and the gum tissue. The hand nozzle 13 includes a switch
21 that may be used for stopping the liquid from being discharged
from the nozzle. The nozzle 13 has an outlet coupling 16 for
receiving individual removable and rotatable nozzle tips 22. The
removable nozzle tip may be attached to the hand nozzle 13 when the
oral hygiene apparatus is being used by any suitable fitment.
Otherwise, when not in use the tip is stored in bracket 15 as shown
in FIG. 1. Several nozzle tips are normally supplied so that the
users, such as a family, may each have one for their personal
use.
A motor pump assembly 11 shown in FIGS. 1 and 2 has a housing 30,
which in the form illustrated is molded from a suitable plastic,
and has sidewalls 18 and a top 19. The front sidewall of the motor
pump housing 30 has on the right-hand side a vertical graduated
scale and a slot 26 adjacent and parallel to the scale in which a
control knob 32 is slidingly movable. The graduated scale indicates
generally the amount of liquid discharge pressure starting at the
bottom end 36 of the slot in the low position and extending
vertically upwardly through transition intermediate ranges to the
upper end 37 of the slot to the high position. Immediately below
the indicated low position, there is an off position.
The housing 30 is attached to the oral hygiene apparatus base 20 by
any convenient means. Within the housing and also attached to the
base 20 is an electric motor 46 with a motor switch assembly 38 for
energizing the motor. In close proximity to the motor and also
secured in place on the base 20 is a pump assembly 24 of the
reciprocating piston type, with the piston being driven by the
electric motor 46 through any appropriate drive-connecting
means.
The amount of liquid pressure discharged from the apparatus system
is controlled by a screw 50 that projects from the end of the pump
assembly 24 and has a slotted head 39. By turning the screw
clockwise or counterclockwise, a valve inside the pump assembly 24
is so positioned that the pressure of the liquid discharge is
controlled, as will be discussed in detail later. Interconnecting
the slotted screw 39 and the control knob 32 is linkage 31. The
linkage comprises two rigid members of similar length. One member
42 has a central longitudinally extending opening or slot 43 nearly
its length. The other rigid member 45 carries two spaced fixed
rivets 44 that pass through the opening 43 in rigid member 42 and
are headed or upset, thereby joining the two rigid members to each
other. While the linkage is rigid, it is also extendable along its
longitudinal axis to compensate for the varying distance between
the slide knob and the stationary pump assembly as the knob is
moved vertically within the confines of slot 26 by the user. The
end portion 40 of rigid member 45 grips the screw 50 tightly, while
the end portion of rigid member 42 is loosely attached to the slide
knob and is free to rotate. By this linkage arrangement, as the
slide knob is moved up and down in the housing slot 26, rigid
member 45 is caused to be correspondingly raised and lowered with
respect to the base 20 and is pivoted about the screw 50. Since the
rigid member 45 grips the screw 50 tightly, the screw is caused to
turn clockwise or counterclockwise as the slide knob 32 is moved up
and down.
With reference to FIGS. 3, 4, 5, and 6, the liquid pump and liquid
pressure control means will be described in detail. In FIGS. 3, 4,
and 5, the pressure chamber 33 of the pump assembly 24 is shown in
cross section. The liquid enters the pump assembly 24 by gravity
flow from the reservoir through conduit 23 which is attached to an
intake port 34 leading into the pressure chamber 33. The pressure
chamber of the preferred embodiment of the oral hygiene apparatus
is cylindrically shaped and has within it a reciprocating piston 35
with a piston rod 52 joined to yoke 51 that is in driven connection
with an electric motor. The driven connection is normally a gear
train, represented as 70 in FIG. 3, that reduces the rate of
rotation of the motor shaft to the desired amount of piston
strokes. During the operation of the pump assembly when the piston
is moved rearwardly within the pressure chamber, liquid is drawn
into the pump chamber through the intake 34 to fill the chamber.
During the forward movement of the piston, the liquid within the
pressure chamber has pressure applied to it and is forced to leave
the pressure chamber through the outlet port 47. The piston should
operate such that there is a good fluid seal between the piston and
the pressure chamber. I have found that a rolling diaphragm made of
flexible material, such as an elastomer, and having a frustoconical
shape with the larger end attached to the cylinder and the smaller
end to the piston, works quite satisfactorily. Attached to the
outlet port 47 is plastic tubing 14 that carries the liquid under
pressure to the hand nozzle for discharge from the apparatus
system. Such a pump produces an intermittent or pulsating stream of
liquid under considerable pressure. The preferred embodiment of my
oral hygiene apparatus is constructed so that the frequency rate of
the liquid pulsation produced by this system will be around 2,000
per minute, and the amount of liquid pressure will be manually
adjustable from about 20 to 90 p.s.i.
With particular reference to FIGS. 4 and 5, the valve means by
which the amount of liquid pressure may be adjusted will be
described. The liquid from the reservoir 10 is drawn into the pump
through intake port 34 at the conical-shaped forward end 58 of the
pressure chamber as the piston 35 moves rearwardly within the
pressure chamber. Valve 48 is lifted from its seated position
during the inrush of liquid, but is retained in operable position
by means of a valve retainer 49. Without a means of retaining the
valve in an operable position, it could travel too far within the
pressure chamber and interfere with the functioning of the liquid
pump. Valve 48 is also conically shaped and complementary with the
shape of the forward end 58 of the pressure chamber. When the
piston 35 moves toward the front of the pressure chamber, valve 48
is caused to seat by the liquid pushing against rear face 69 of the
valve, and when seated it prevents any liquid from passing beyond
the valve in the direction of the intake port 34, thus forcing the
liquid under pressure out of the pressure chamber through the
outlet port 47. The amount of liquid pressure delivered through the
outlet port may be adjusted by preventing valve 48 from completely
seating, thereby allowing some of the liquid under pressure to
escape back into the inlet port 34 during the forward movement of
the piston. The more liquid permitted to escape back into the inlet
port, the less pressure there is applied to the liquid passing
through the outlet port 47.
As shown in FIG. 4, seating of valve 48 may be prevented by screw
50 that carries an integrally attached projection 55 which
protrudes into the forward end 58 of the pressure chamber 33 and
contacts the front face 53 of valve 48. FIG. 4 represents the valve
and screw position under the lowest liquid pressure condition where
the valve 48 is unseated to its maximum extent. The valve 48 is
provided with several passages 56 through a portion of its
conically shaped surface to enable the liquid from the pressure
chamber 33 to flow past the valve 48 back into the inlet port 34
when the valve is unseated. The passages 56 on the surface of valve
48 are constructed such that the closer the valve is to being
seated, the more restricted the passages become, thereby reducing
the amount of liquid permitted to flow past the valve into the
inlet port 34. FIG. 4 represents the position of the valve and
screw under the highest pressure condition wherein the valve is
fully seated. Backflow of liquid past the valve 48 is prevented, in
this instance since the passages 56 are sealed by the wall of the
conical forward end 58 of the pressure chamber, and as a result the
liquid passing through outlet port 47 is under maximum pressure.
With finger projection 55 passing through the wall of the pressure
chamber of the pump, the opening should be sealed against leakage.
An O-ring 57 prevents such leakage yet allows the finger to rotate
and move inwardly and outwardly of the pressure chamber.
By turning the screw 50 counterclockwise, it will travel in
stationary guide bushing 54 inwardly of the pump, thus carrying the
finger projection 55 with it until the end of the finger projection
contacts front face 53 of the valve 48. By continuing the inwardly
movement of the screw and finger projection, the valve is unseated
by pushing it toward the rear of the pressure chamber, and the
valve is prevented or blocked by the finger projection from being
seated even during the forward pressure applying thrust of the
piston. Turning the screw 50 clockwise withdraws the finger
projection 55, thus allowing the valve to seat, as shown in FIG. 5,
when the piston is moving forward.
FIG. 6 is a cross-sectional view of the pressure chamber of the
pump taken along line 6-6 of FIG. 4. This particular figure shows
how valve 48 is retained in operable position within the conical
portion 58 of the pressure chamber by means of a valve retainer 49.
The valve retainer 49 is a spring clip that is maintained in
position in the throat of the outlet port 47 in the pressure
chamber. One end of the valve retainer is continuous and formed in
the shape of a loop 60 slightly larger than the inside diameter of
the outlet port 47. The opposite end 71 of the valve retainer 61 is
bifurcated and extends into the pressure chamber 33 to act as a
stop means to prevent the valve 48 from moving too far from the
conical portion 58 during the inrush of liquid into the pressure
chamber during rearward movement of the piston.
With particular reference to FIG. 3, there is within the pump and
motor housing a switch assembly 38 that controls energizing the
motor. This particular switch is a normally biased on switch in
that there is a plunger 62 which will actuate the switch, as by
making the necessary contacts when the plunger is in its extended
position. Conversely, when the plunger is depressed to overcome the
normally biased on condition, the switch is deactuated. On the
control knob 32 interiorly of the motor and pump assembly housing,
there is a cam element 63 integrally formed therewith which comes
in contact with the plunger 62 when the control knob 32 is in the
low-pressure position. By moving the control knob vertically
downwardly to the off position indicated on the graduated
pressure-indicating scale, the cam element 63 causes the plunger 62
to be depressed by camming action. In the off position, the base 64
of the control knob abuts the base 20 of the oral hygiene apparatus
and is prevented from traveling any further in the downwardly
direction. Therefore, as long as the control knob is in this
position, the switch will not be actuated, and the motor cannot be
energized. Only when the knob is vertically raised, will the switch
be actuated and the motor started, because the biased plunger 67 is
permitted to extend itself and make the necessary electrical
contact. It should be noted that with this arrangement, when the
motor is energized the control knob is in the low-pressure setting.
Therefore, there is positive assurance that the motor switch can
only be actuated to energize the motor when the control means is
adjusted for low-pressure liquid discharge.
The electric motor used in my oral hygiene apparatus is one with a
lower starting than run torque, such as a shaded pole motor. Shaded
pole motors are popular for driving loads needing only a low
starting torque motor, such as fans. Shaded pole motors are
particularly desirable for such applications because they operate
quietly and are the simplest and most inexpensive of single phase
induction motors. Shaded pole motors have a continuous solid copper
loop around a small portion at each salient pole. This shorted
loop, or shading coil, causes the reaction necessary to give the
motor its starting torque. The coil produces only moderate torque,
and upon starting the motor the torque is quite low but does
increase as its speed increases. Because of these torque
characteristics, shaded pole motors have limited application.
One of the problems in designing a liquid pumping system, such as
in the case of oral hygiene apparatus, wherein the liquid is
incompressible, the motor furnishing the drive means for the piston
of the liquid pump must have a starting torque sufficient to
overcome the load of the system in which it is used. The higher the
liquid pressure setting for the apparatus system, the greater the
starting torque load on the motor. The performance curve of a
shaded pole motor is shown in FIG. 7, with the motor torque plotted
against the increase in speed of the rotation of the motor shaft.
It is noted from the curve that upon initially starting the motor,
the torque is at a very low value, as represented by point S. As
the speed of the motor increases, the motor torque increases until
it reaches a fairly high speed and maximum torque represented by
point M. Beyond the speed at which maximum torque is achieved, the
torque decreases. The line designated Low Load represents the
torque load of the liquid pump apparatus when the liquid pressure
is minimum or on the low setting, and the High Load line is when
the liquid pressure is maximum or on the high setting. The torque
load line for the apparatus and the motor torque curve should
intersect each other only once and as close to a right angle as
possible for that represents a motor that will function properly
under the torque load at normal operating conditions, taking into
account the usual manufacturing tolerances and voltage variations.
From the torque curve in FIG. 7, it can be seen that such a
condition exists with the Low Load line at point I. In the case of
the High Load line, however, it intersects the motor torque curve
at two points, X and P. The tangential intersection of the High
Load line and the torque curve at point X is at low motor speed.
When this occurs, the motor will usually continue to operate, but
only at the speed indicated by Point X. The motor will not obtain
its correct speed of operation. The result is that the efficiency
of the motor is reduced, and the life of the motor is detrimentally
affected. Usually the motor will overheat and eventually burn
out.
My apparatus is controlled, as discussed above, such that the
apparatus load that the motor torque must overcome without inducing
motor failure is that represented as the Low Load line in FIG. 7.
Because of the unique control incorporated in my oral hygiene
apparatus, the motor switch is actuated to energize the motor when
the liquid pressure is adjusted for low-pressure discharge.
Therefore, an electric motor with a low starting than run torque
may be used, particularly a shaded pole motor with minimum starting
torque capacity under Low Load conditions of the apparatus. I have
found that an alternating current, shaded pole induction motor of
the open construction type having two poles, a squirrel cage rotor,
and a five-eighths inch stack of laminations, performs quite
satisfactorily in my oral hygiene apparatus.
In the operation of my oral hygiene apparatus, the user will insert
a power plug into a proper outlet for providing electric current to
the electric motor. The control knob 32 will be in the off position
at the bottom of slot 26. The reservoir 10 is filled with liquid
and in place on top of the motor pump housing 30 for supplying
liquid to the apparatus system. The control knob 32 is raised
vertically from the off position to the low-pressure position which
allows the biased plunger 62 to extend itself and actuate the
switch 38, thereby energizing the electric motor. The motor through
a gear train 70 drives the piston 35 in a reciprocating motion
within the pressure chamber 33. With the control knob at the
low-pressure setting, the screw 50 and finger projection 55 unseat
the valve 48 and prevent it from reseating at this pressure
setting. During the rearward movement of the piston, liquid is
drawn into the pressure chamber. The piston during its forward
movement applies pressure to the liquid in the pressure chamber,
thereby forcing a portion of the liquid out the outlet port 47,
through the tubing 14, for ultimate discharge from the apparatus
system by the nozzle 13. A portion of the liquid will also back
flow past unseated valve 48 into the inlet port 34. The user may
increase the liquid pressure by moving slide knob 32 vertically
upwardly in slot 26, which raises rigid member 45 of the linkage 31
away from the base 20 of the apparatus and causes the screw 50 to
turn clockwise, thus withdrawing finger projection 55 from from the
pressure chamber. By withdrawing finger projection 55, the valve 48
can move in the direction of being seated, thereby restricting the
amount of liquid flowing past the valve 48 to the inlet port 34,
thus increasing the pressure of the liquid passing through the
outlet port 47. When use of the oral hygiene apparatus is to be
discontinued, the user moves the control knob vertically downwardly
to the off position. By so doing, the cam element 63 depresses the
plunger 62 to deactuate the switch 38 and turn the electric motor
off. If desired, the reservoir may then be emptied, inverted, and
placed over the tubing, hand nozzle, and nozzle tips adjacent the
motor and pump housing as a dust cover.
The foregoing is a description of the preferred embodiment of the
invention, and variations may be made to the apparatus without
departing from the spirit of the invention, as defined in the
appended claims.
* * * * *