U.S. patent number 3,763,859 [Application Number 05/197,661] was granted by the patent office on 1973-10-09 for injector apparatus.
This patent grant is currently assigned to Pigmy Health Products, Inc.. Invention is credited to Ben Pansky, Howard M. Yanof.
United States Patent |
3,763,859 |
Yanof , et al. |
October 9, 1973 |
INJECTOR APPARATUS
Abstract
The specification and drawings disclose an apparatus for
dispensing or injecting substances such as medicaments. The
disclosed apparatus includes a dispensing chamber associated with a
source of pressurized fluid which can serve to expel substances
from the chamber. A movable housing or the like is provided for
containing first and second different substances which, in the case
of medicament injection, are preferably medicament and cleaning
fluid. Flow of the substances to the chamber is regulated by a
valve assembly. Additionally, a control assembly is provided for
requiring that the second substance be supplied to the chamber
following a predetermined number of expulsions of the first
substance. In the particular embodiment disclosed, the first
substance is the medicament and the second substance is the
cleaning fluid. This arrangement thus prevents repeated uses of the
device for ejecting medicament without a cleaning operation.
Inventors: |
Yanof; Howard M. (Toledo,
OH), Pansky; Ben (Toledo, OH) |
Assignee: |
Pigmy Health Products, Inc.
(Shaker Heights, OH)
|
Family
ID: |
22730269 |
Appl.
No.: |
05/197,661 |
Filed: |
November 11, 1971 |
Current U.S.
Class: |
604/70;
222/144.5; 604/71; 137/240; 222/389 |
Current CPC
Class: |
A61M
5/30 (20130101); A61M 5/2053 (20130101); Y10T
137/4259 (20150401); A61M 2005/005 (20130101); A61M
5/001 (20130101) |
Current International
Class: |
A61M
5/30 (20060101); A61M 5/20 (20060101); A61M
5/00 (20060101); A61m 005/30 () |
Field of
Search: |
;128/173H,218A,218C,274,DIG.12 ;222/144,144.5,389,148 ;137/240
;239/304,305,307,104,112,113,414 ;251/75 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Cohen; Lee S.
Claims
What is claimed is:
1. In a velocity type injector including a chamber from which a
substance can be expelled by the use of a pressurized fluid, a
source of said pressurizing fluid connected to said chamber by a
first passageway, and movable means for selectively moving at least
a first source and a second source of different substances to a
supply position wherein they are connected with said chamber
through a second passageway, the improvement comprising control
valve means in said first and second passageways operable in at
least two directions for regulating flow of a substance from said
supply position through said second passageway to said chamber and
for regulating flow of said pressurizing fluid through said first
passageway to said chamber and lock means for preventing movement
of said valve means in one of said two directions when said first
source is at said supply position and after said first source has
been supplied to said chamber.
2. The injector as defined in claim 1 wherein operation of said
lock means is interrelated with said movable means.
3. The valve as defined in claim 1 wherein said lock means includes
means for preventing movement of said valve means until said
movable means has been moved to bring the second source of
substance to said supply position.
4. The valve as defined in claim 1 wherein said lock means engages
said valve means at the end of movement in either of said at least
two directions.
5. In a velocity-type injector having separate supplies of
medicament and cleaning fluid and a source of pressurized gas and
passage means for connecting said supplies and said gas to a
chamber wherein said supplies can be expelled by said pressurized
gas supplied to said chamber, the improvement comprising valve
means for regulating the flow of gas and fluid to said chamber
through said passage means, and control means for requiring that
cleaning fluid be supplied to said chamber following a selected
number of discharges of medicament fluid.
6. The injector as defined in claim 5 wherein said control means
includes means for preventing movement of said valve means
following movement of said valve means in one direction until a
different one of said supplies has been connected to said
chamber.
7. The valve as defined in claim 5 wherein said medicament and
cleaning fluid supplies are carried in movable means and wherein
said control means are operated by movement of said movable
means.
8. The injector as defined in claim 5 wherein said valve means
comprise a slide valve member and wherein said medicament and
cleaning fluid supplies are carried in movable means.
9. The valve as defined in claim 8 wherein said control means
includes a lock member engageable with said slide valve and
operable by said movable means.
10. The valve as defined in claim 8 wherein means are provided for
controlling the velocity of movement of said slide valve
member.
11. The valve as defined in claim 10 wherein said means for
controlling the velocity of said slide valve member comprise
over-center spring means.
12. The valve as defined in claim 8 wherein said lock means include
at least one pin member carried in said movable means and
engageable with said slide valve member.
13. An apparatus for dispensing substances comprising:
means defining a dispensing chamber;
means for containing a source of pressurized fluid for expelling
substances from said chamber;
movable means for holding first and second different
substances;
conducting means located at a first position for connecting said
substances to said chamber, valve means for regulating connection
of said conducting means with said chamber; and,
means for requiring that said second substance be supplied to said
chamber after said first substance has been supplied to said
chamber for a predetermined number of consecutive times.
Description
The subject invention is directed toward the dispensing art and,
more particularly, to a self-contained apparatus for dispensing
high velocity streams of substances.
The invention is particularly suited for use in injecting
medicaments and the like and will be described with reference to an
injector of the general type generally referred to as a "velocity"
injector; however, as will become apparent, the apparatus could be
used for dispensing or injecting other types of fluids, or flowable
substances.
Self-contained "velocity" type medicament injectors are known.
Typically, the injectors comprise a chamber having an outlet nozzle
and a movable piston for expelling medicament from the chamber and
through the nozzle. Generally, small CO.sub.2 cartridges or the
like are used for supplying a relatively high gas pressure for
moving the piston. Control valves regulate the supply of gas to the
piston.
One of the problems present in prior velocity-type injectors has
been the difficulty of cleaning them following a medicament
injection operation. Because of the small passages and the enclosed
chamber, it has generally been necessary to substantially
completely disassemble the units for cleaning. This has been a
difficult and time consuming job and, for this reason,
velocity-type injectors of the smaller self-contained variety have
not been widely used.
The subject invention provides an injector of the general type
described wherein both the medicament and cleaning fluid are
carried within the unit and arranged so that cleaning must take
place following a predetermined number of medicament injections.
The invention is preferably arranged so that a cleaning operation
is required following one or more medicament injections.
The invention also provides an improved control arrangement between
the cleaning-medicament supply sources and the dispensing chamber
so that a differential rate of firing for the cleaning and
medicament fluids can be provided so that when the cleaning fluid
is being dispensed from the chamber, it will not be under
sufficient pressure for a great enough time to allow penetration of
the skin.
In accordance with one aspect of the invention, there is provided
an apparatus for dispensing substances which includes a dispensing
chamber associated with means for containing a source of
pressurized fluid which can serve to expel substances from the
chamber. Additionally, movable means in the form of a housing or
the like are provided for containing first and second different
substances which, in the case of a medicament injector, are
preferably medicament and cleaning fluid. Located at a first
location are means which serve to connect the substances with the
chamber. Flow of the substances to the chamber is regulated by
valve means associated with the conducting means. Additionally,
means are provided for requiring that the second substance be
supplied to the chamber following a predetermined number of
expulsions of the first substance. In the particular embodiment
disclosed, the first substance is the medicament and the second
substance is the cleaning fluid. This arrangement thus prevents
repeated uses of the device for ejecting medicament without a
cleaning operation.
Preferably, and in accordance with a more limited aspect of the
invention, the movable means comprise a rotatable housing in which
the first and second different substances are carried in separate
removable capsules or cartridges. The means for requiring that the
second substance be supplied to the chamber after a predetermined
number of expulsions of the first substances include means
interconnected between the movable cylinder and the valve means.
These means are disclosed in the drawings as pin members associated
with the movable means and adapted to engage the valve means
following its movement.
A further aspect of the invention concerns the provision of means
for providing a differential firing rate so that the supply of gas
pressure to the chamber can be different, depending upon the
particular fluid being expelled. For example, when used as a
medicament injector, the differential firing rate permits the
medicament to be expelled at one velocity and the cleaning fluid at
another. This serves as a safety mechanism for preventing
inadvertent injection of cleaning fluid into the body.
Another aspect of the invention contemplates that the cleaning
fluid and the medicament will be drawn into the dispensing chamber
by manual movement of a piston carried in the chamber. Alternately,
other aspects of the invention contemplate that it would be
possible to utilize pressurized containers of cleaning fluid so
that cleaning fluid is flushed through the unit automatically upon
operation of the control valve. Another somewhat limited aspect of
the invention contemplates that the movable cylinder which carries
the medicament and cleaning fluid will be arranged with cleaning
fluid and medicament at alternate locations so that cleaning must
be carried out following each medicament injection.
A still further, somewhat limited aspect of the invention is
directed to the use of a single slide valve member for controlling
gas, cleaning fluid, and medicament supplied to the injection
chamber. This valve is preferably interlocked with the movement of
the medicament and cleaning fluid supplies.
Accordingly, a primary object of the invention is the provision of
a velocity-type injector apparatus wherein plural different fluids
can be dispensed with means that require one fluid to be dispensed
following a predetermined number of injections or expulsions of
another substance.
A further object of the invention is the provision of an apparatus
of the type described wherein the rate of dispensing of the fluids
can be varied.
A still further object is the provision of an apparatus of the type
described wherein the dispensing means includes means for varying
the quantity of fluid dispensed as well as its velocity.
The above and other objects and advantages will become apparent
from the following description when read in conjunction with the
accompanying drawings wherein:
FIG. 1 is a top view of a medicament injector formed in accordance
with a preferred embodiment of the subject invention;
FIG. 2 is a cross-sectional view taken on line 2--2 of FIG. 1 and
showing in some detail the internal operating mechanisms of the
injector;
FIG. 3 is a left side elevation (taken on line 3--3) of the
injector shown in FIG. 1;
FIGS. 4 through 6 are enlarged views of the valve member showing it
in various positions of movement;
FIG. 7 is an end view of the injector taken on line 7--7 of FIG.
1;
FIG. 8 is a cross-sectional view through the medicament and cleaner
portion of the injector and taken on line 8--8 of FIG. 1;
FIG. 9 is a partial side elevational view taken on line 9--9 of
FIG. 1 with portions broken away to show the over-center mechanism
used for controlling valve operation;
FIG. 10 is a cross-sectional view taken on line 10--10 of FIG. 3
and showing the details of one of the check valve mechanisms;
and,
FIG. 11 is an enlarged view of one of the valve mechanisms of the
unit.
THE UNIT IN GENERAL
Referring more particularly to the drawings wherein the showings
are for the purpose of illustrating a preferred embodiment of the
invention only and not for the purpose of limiting the same, FIGS.
1 and 2 best illustrate the overall arrangement of the injector
unit 10 which broadly includes a variable volume injector chamber
assembly 12, a valving or control assembly 13 and
medicament-cleaning fluid supply assembly 14.
The unit 10 is shown in the drawings somewhat larger than the
preferred actual size. However, it should be appreciated that not
only the size, but the configuration and structural details of the
device could vary substantially within the scope of the
invention.
In the embodiment shown, the assemblies 12 and 13 are carried in a
first body or housing member 16 which can be formed from any
suitable material or combinations of materials, either metals,
plastics or ceramics. The medicament-cleaning fluid supply assembly
14 is, in the subject embodiment, mounted from the first body
portion 16 for movement relative thereto. Preferably, the assembly
14 is rotatably mounted and includes a cylindrical body or housing
18 carried for rotation generally about the longitudinal center
axis of the unit. The details of section 14 will subsequently be
described.
Before dealing with the more specific aspects of the unit, it
should be understood that the unit is arranged so that selective
rotation of housing 18 allows medicament or cleaning fluid to be
indexed to a position wherein they can be supplied through the
valve assembly 13 to the injector chamber assembly 12.
INJECTION CHAMBER ASSEMBLY 12
Referring more particularly to the variable volume injection
chamber assembly 12, it will be seen that it comprises an elongated
cylindrical chamber 20. Chamber 20 is divided into two variable
volume sections 34 and 36 by a reciprocable piston member 22. The
chamber 20 is defined by a sleeve member 24 which is press-fitted
in a bore 26 formed through the forward end of body portion 16. The
lower end of sleeve 24 has an enlarged flange section 27 which
engages the lower surface of body portion 16. The injection or
outlet nozzle of the unit is removably mounted in the flange
portion 27. Note that the nozzle 28 is threaded in a bore formed
through flange portion 27. An insert 30 which defines the
medicament outlet orifice 32 is press-fitted in nozzle 28. This
arrangement allows the nozzles to be changed as required for
different types of injections. Additionally, the orifice defining
insert in the nozzle member can be changed so that during
manufacturing, one common nozzle can be used with different inserts
to provide different nozzle assemblies with variable numbers and
sizes of orifices.
It should be understood that all portions of the assembly which are
contacted by medicament should preferably be formed from materials
which will provide a non-wettable surface.
Referring again to piston 22, it will be seen that, as mentioned
above, piston 22 divides the chamber 20 into a medicament chamber
portion 34 and a pressurizing gas chamber portion 36. It should be
appreciated that rather than a piston as shown, a movable diaphragm
or the like could, in certain instances, equally well be used. In
the embodiment under consideration, piston 22 is formed from a
suitable elastomeric material and mounted for sealed, sliding
movement within the sleeve 24. A stem member 38 is connected to the
piston and extends axially upwardly through the chamber 36. The
stem 38 is guided by a sleeve 40 which extends downwardly from an
externally threaded adjustment member 42. Member 42 is threadedly
received in a collar member 44 press-fitted in the upper end of
bore 26. It should be appreciated that by rotating the knurled
outer end flange 46 of the threaded member 42, the lower end of
member 40 can be adjusted in a vertical direction to vary the upper
limit of movement of the piston 22. This permits the volume of the
medicament chamber section 34 to readily be controlled.
The upper chamber section 36 is supplied with gas or other
pressurizing fluid at a pressure sufficiently high to drive the
piston 22 downwardly to expel medicament from the chamber 34 at a
desired velocity. For this reason, the gas chamber 36 is preferably
sealed by a seal ring 48 which is carried on the upper end of
member 40 and engages the internal walls of the sleeve 24.
Similarly, a seal ring 50 is carried within member 40 and about the
stem 38.
As can be appreciated, by controlling the supply of medicament to
the chamber portion 34 and the supply of pressurized gas to the
chamber portion 36, the medicament can be expelled through the
orifice 32 at a velocity sufficiently high to penetrate to
substantially any desired depth. Velocity and depth of penetration
can, of course, be controlled by the pressure at which the gas is
supplied, or the orifice size, etc.
The supply of medicament, cleaning fluid and pressurizing gas to
the chamber 20 is controlled, as mentioned, by the assembly 13.
CONTROL ASSEMBLY 13
Referring in particular to FIGS. 2, and 4 through 6, the preferred
form for control assembly 13 is shown, however, it should be
appreciated that various other arrangements could be used. In the
embodiment shown, the control assembly comprises a generally
cylindrical slide valve member 54 which is mounted between the
chamber assembly 12 and the cleaning-medicament supply assembly 14.
The cylindrical slide valve 54 is carried for reciprocation in a
cylindrical bore 56 formed vertically through the body portion 16.
In the embodiment under consideration, the valve member 54 is
permitted to have free sliding movement while being prevented from
rotating by a key member 58 which is fitted in aligned grooves
formed in the bore 56 and the valve member 54. At the opposite
axial ends of member 54, there are reduced diameter portions 60 and
62 which can be formed integrally with the main valve body or
affixed thereto. It should be noted that the reduced diameter end
portions extend outwardly through guide members 66 and 67
respectively. The guide members are preferably merely press-fitted
in counterbores formed at the ends of the bore 56.
Although the operational details of the valve member 54 will
subsequently be described in detail, it should be noted that, as
best shown in FIGS, 2, 4, 5 and 6, the valve is provided with a
pair of circumferentially extending seal or piston ring members 68
and 70. The seal rings can be formed from any suitable material but
are preferably formed from Teflon. Positioned between seal rings 68
and 70 is a first through-bore 74 and a pair of spaced flow
passages 75 and 76. A bore 78 connects through the body 16 with the
chamber portion 36. By reciprocating the valve member 54, selected
ones of passages 74 through 76 are connected with the passage 78.
Referring to FIG. 3, it will be understood that the passages 74 and
75 extend laterally to connect with a vent passage 80 formed
through body 16.
The right-hand end of passage 74 (as viewed in the drawings) has a
cam surface 81 (see FIG. 4) formed generally about it. Cam surface
81 serves to operate a check or shut-off valve 82 which is carried
in a bore 84. Note that valve 82 is arranged for reciprocation in
the bore 84 and has an enlarged head 86 adapted to sealingly engage
the conically shaped portion of bore 84. The stem portion of the
valve 82 is provided with flow grooves 83 (see FIGS. 4 through 6)
to permit flow about it when the head 86 is moved away from the
conical portion of the bore. In the position shown in FIGS. 2, 4
and 6, the contour of the cam surface 81 permits the valve member
82 to be moved to the left under the influence of the gas pressure,
thereby closing the passage or bore 84. However, when the valve
member 54 is reciprocated from either of the positions shown in
FIGS. 4 or 6, the inner end of the valve 86 is cammed to the right
causing it to open and allowing flow of pressurizing gas through
the bore 84.
As previously mentioned, the pressurizing gas supply for the unit
is preferably a gas cartridge member 88 which is removably carried
in the unit. For example, commercially available CO.sub.2
cartridges can be used. As shown in the subject embodiment, the gas
cartridge 88 is received in a generally cylindrical housing portion
90 (see FIG. 2) which is threadedly connected to the body portion
16. A needle member 92 is carried in the forward end of the housing
90 and serves to pierce the seal of the gas cartridge 88. As can be
appreciated, the cartridge is removed and replaced from the unit by
removal of the cylindrical end cover 94 which is removably
connected to the outer end of the body portion 90 by cooperating
threads. A knurled outer end flange facilitates removal of end
cover 94.
Referring again to FIGS. 2, and 4 through 6, it will be seen that a
pair of parallel passages 100 and 102 are formed through the lower
end of the valve member 54. These passages are arranged to
alternately connect a passage 104 (which leads to the medicament
chamber 34) with a passage 106. Passage 106 is connected with a
flow needle 108 carried in an insert 109 threaded in body 16 as
shown in FIG. 2. For reasons which will subsequently be discussed,
a second somewhat longer needle 110 is mounted parallel to needle
108 and connects through passage 112 and lateral passage 114 (see
FIG. 10). Passage 114 is a vent passage and is connected to
atmosphere through a small check valve 116 carried in a threadedly
mounted insert 118. Insert 118 also includes a bacterial filter
member 120. A small, perforated cover member 122 encloses the outer
end of the valve insert 118.
Although their function will subsequently be described in detail,
it should be noted that the unit includes safety lock assemblies
124 which are carried in the medicament-cleaner assembly 14 and
cooperate with recesses 126 and 128 formed in the slide valve
member 54.
THE CLEANING-MEDICAMENT SUPPLY ASSEMBLY 14
The cleaning-medicament assembly 14 of the unit is arranged so that
separate containers of medicament and cleaner can be selectively
brought into position for filling and/or cleaning the chamber
portion 34. Additionally, one aspect of the invention proposes to
interlock the operation of the (cleaning-medicament) supply
assembly with the valve 54 so that cleaning fluid must be passed
through the medicament chamber prior to each filling with
medicament or after each shot. Further, the assembly is arranged to
prevent inadvertent injection of cleaning fluid.
Broadly, in the preferred embodiment, the cleaning fluid and
medicament are carried in separate disposable containers 131 and
133, respectively, which are arranged to be indexed to a location
at which they can be selectively connected with the chamber portion
34. The indexing movement could be achieved with many different
types of structures from simple slide-type cartridges to more
complicated non-linear movement arrangements. In the subject
embodiment, the medicament and cleaner are carried in the rotating
cylinder-like housing member 18 which is mounted for rotation about
the cylindrical body portion 90 and the cylindrical end cap 94. As
best shown in FIG. 2, the housing member 18 is rotatable about the
member 90 and, also, can be reciprocated axially outwardly to the
dotted line position. A compression spring 138 is positioned
between a shoulder 140 formed in the housing 18 and the end 142 of
the cylindrical cap member 94. This maintains the cylinder
continually biased to the left, as viewed in FIG. 2.
Referring to FIG. 8, it will be noted that the housing member 18
includes a plurality of spaced, longitudinally extending openings
146 and 148 which are spaced circumferentially about the cylinder.
In the embodiment shown, the openings are alternately located so
that, for example, each opening 146 will contain a container 131 of
cleaning fluid, while each location 148 will contain a container of
medicament 133. Preferably, the containers are of differing size or
configuration so that a cleaner container cannot inadvertently be
inserted in a medicament chamber or vice versa.
The medicament and cleaning fluid containers are maintained in the
openings 146, 148 by a cover plate member 152 which is releasably
connected to the housing 18 in any convenient manner, such as
through the use of a pair of screws 156 (see FIGS. 7 and 8).
SAFETY LOCK 124
Referring again to the safety lock 124, it will be seen that, as
best shown in FIGS. 2 and 8, a safety lock 124 including a pin
member 158 is associated with each of the medicament chamber
openings 148. The pin members 158 are slidably mounted in bores 160
and continually biased in an outward direction by a compression
spring 162. Guide members 161 are press-fitted in the ends of bores
160. An enlarged head portion 164 is formed on the pin 158 and
prevents it from moving out of the bore 160. Formed in the body
portion 16 are openings 170, 172 which are aligned with the slide
valve bore 56. With the cylinder 18 in the position shown in FIG.
2, pin 158 extends through opening 170 until its inner end engages
the slide valve member 54. However, when the slide valve 54 is at
the downward end of bore 56, pin 158 will enter the recess 126
because of spring 162 to prevent the valve from being moved
upwardly. The reasons for this interlock will subsequently be
described with reference to the overall operation of the device.
The interlock arrangement also contemplates that when the cleaning
container is moved into the position in alignment with the needles
108 and 110, a diagonally opposite medicament chamber having a lock
pin 158 will be in position with its pin aligned in opening 172.
This minimizes the possibility of the valve member 54 from being
moved downwardly for medicament fire operation. However, when the
valve member 54 is in a down position of FIG. 6, (following a
medicament firing) and the housing has been rotated to bring a
cleaning cartridge into alignment with needles 108 and 110, the
valve can thereafter to moved upwardly until the pin enters the
recess 128. The reason for this will likewise be explained with
reference to the overall operation of the device.
OPERATION OF THE UNIT
The operation of the unit can best be understood by reference to
FIGS. 2, and 4 through 6. FIG. 2 shows the assembly at the start of
a fill operation. The piston, however, is shown at mid-point
between a fill and discharge operation. For the purposes of the
subject explanation, assume that the piston is at the bottom of the
cylinder. It should be noted that a medicament cartridge 133 is
aligned with the needles 108 and 110. The needles, of course,
extend through the seal on the medicament cartridge and allow its
contents to be connected with passage 106. At this time, the piston
operating shaft 38 can be pulling up, causing medicament to be
withdrawn from the medicament cartridge 133 through lines 106, 102,
and 104 to the chamber portion 34. The amount of medicament
withdrawn from the cartridge is, of course, controlled by the
adjustment of the sleeve 40. When the stem has been retracted to
the position wherein the piston is in engagement with the
undersurface of member 40, the apparatus is ready for firing. To
fire the device, the outwardly extending reduced diameter portion
62 of the valve member 54 is pressed inwardly. This causes the cam
surface 81 to open valve 82 (see FIG. 5) to permit pressurizing gas
to pass through the bore 84, passages 74 and 78 to the upper gas
pressurizing chamber 36 to drive the piston downward and expel the
medicament through the discharge nozzle or orifice 32. After the
passage 74 passes the valve 82, the second portion of the camming
surface allows the valve 82 to close (see FIG. 6). Simultaneously,
the gas pressure chamber 36 is vented to atmosphere by passage 75
being aligned with passage 78 and vent passage 80 (see FIG. 3).
When the valve member 54 is in its downward position, the pin 158
enters the recess 126 and prevents movement of the valve to the
upper position. The only way in which the valve can be moved to the
upper position is by retracting the medicament/cleaner housing 18
to the dotted line position of FIG. 2 and then rotating it
sufficiently to bring the adjacent cleaning cartridge in alignment
with the needles 110 and 108. Thereafter, the housing 18 is
released so that it moves to the left and needles 108 and 110
penetrate the seal of the cleaning cartridge. It must be remembered
that, at this time, a medicament cartridge and its associated lock
pin are in the position shown for the cleaner cartridge in FIG. 2.
Accordingly, cleaning can now take place merely by retracting or
withdrawing the piston stem 38 to pull cleaning fluid through the
needle 108, passages 100 and 104 to the medicament chamber portion
34. The valve member 54 can then be moved upwardly by pressing
against the reduced diameter lower end portion 60 and causing the
camming surface 81 to pass over the end of the valve member 82 to
allow pressurizing gas into the pressurized gas chamber 36. This
expels the cleaning fluid from the medicament chamber to clean the
nozzle. Any type of suitable cleaning fluid could be used.
Alternately, rather than manually withdrawing the cleaning solution
by retracting the stem 38, it should be appreciated that the
cleaning solution (as well as the medicament) could be under a
slight pressure so as to automatically discharge into the
medicament chamber, as shown in FIG. 10.
After the valve stem has been moved back upwardly, the pin 158
which is at that time in passage 172, enters the groove 128 to
prevent the apparatus from being fired again until a medicament
chamber has been moved into position in alignment with the needles
108 and 110.
As can be appreciated, in many instances, it is desirable to have
the movements of the valve member 54 controlled so that the
duration of gas pressure application to the pressure chamber
portion of the cylinder is regulated. Additionally, it is also
desirable, in many instances, to arrange the control valve so that
its opening movement is not completely dependent on the user's
speed of actuation. For this reason, the valve is preferably
provided with an over-center spring mechanism. Many types of
over-center or snap acting mechanisms could be used, however, a
preferred form of mechanism is shown in FIG. 9. As shown, the
mechanism is mounted in a recess 180 formed in the side of the body
portion 16. In general, the mechanism includes first and second
compression springs 182 and 184 which are respectively connected to
pins 186 and 188. Their opposite ends are connected to and act
against a pin 189 which extends laterally from the valve member 54
through a slot 191. As the valve 54 is moved downwardly, the
effective force components placed on pin 189 by the springs change
because of the varying angles of application. At some mid-point,
forces exerted by spring 182 overcome those exerted by spring 184.
Thereafter, the valve is rapidly moved the remainder of the
distance to the opposite position. Although not shown, adjusting
means can be provided for varying the forces exerted by one or the
other of the springs to change the point at which the over-center
action takes place. Further, it should be appreciated that by using
springs having different time constants, the rate of movement of
the valve member can be regulated.
The invention has been described in great detail sufficient to
enable one of ordinary skill in the art to make and use the same.
Obviously, modifications and alterations of the preferred
embodiment will occur to others upon a reading and understanding of
the specification and it is our intention to include all such
modifications and alterations as part of our invention insofar as
they come within the scope of the appended claims.
* * * * *