U.S. patent number 3,908,651 [Application Number 05/470,717] was granted by the patent office on 1975-09-30 for medicament injection device.
This patent grant is currently assigned to Daystrol-Scientific, Inc.. Invention is credited to Robert G. Fudge.
United States Patent |
3,908,651 |
Fudge |
September 30, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Medicament injection device
Abstract
A device for injecting medicament without the use of a needle is
disclosed wherein medicament is expelled from the device at high
pressure, caused to break the skin of a patient, and appropriately
forced into the patient's body. A preferred embodiment of the
present invention is a jet injector having a piston slidably
movable within a medicament chamber to selectively change the
volume of the medicament chamber and a mechanism for advancing the
piston including releasably held springs which may be compressed by
a winding mechanism or pressurized fluid. Medicament is provided to
the medicament chamber from a medicament container mounted on the
injector by a container holder assembly including flexible fingers
that can be caused to grasp the pierceable cap of the medicament
container. Medicament is then selectively directed from the
medicament container to the medicament chamber by valving which, in
a first position, interacts with a safety to provide air to the
medicament container during the filling of the medicament chamber
and, in a second position, allows injection into the patient while
the safety prevents movement of the valve member from the second
position during injection and simultaneously blocks air
communication to the medicament container.
Inventors: |
Fudge; Robert G. (Minneapolis,
MN) |
Assignee: |
Daystrol-Scientific, Inc.
(Minneapolis, MN)
|
Family
ID: |
23868747 |
Appl.
No.: |
05/470,717 |
Filed: |
May 17, 1974 |
Current U.S.
Class: |
604/71; 222/325;
604/183 |
Current CPC
Class: |
A61M
5/30 (20130101); A61M 5/204 (20130101) |
Current International
Class: |
A61M
5/30 (20060101); A61M 5/20 (20060101); A61M
005/30 () |
Field of
Search: |
;128/173H,215,218G,218DA,218R,272,2F ;222/325
;141/383-386,18,19,329,330 ;285/322 ;184/15A,26 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Recla; Henry J.
Attorney, Agent or Firm: Wicks & Nemer
Claims
1. Apparatus for providing jet injection of medicament for use in
combination with medicament stored in containers comprising, in
combination: an injector body; an injector nozzle on one end of the
injector body; a medicament chamber within the injector body; first
means for selectively changing the volume of the medicament chamber
to cause suction of medicament therein and expulsion of medicament
therefrom; second means for receiving medicament from a medicament
container; a medicament passageway for providing medicament
communication between the second means and the injector body; a
valve member located within the injector body having a first
position for directing medicament from the medicament passageway to
the medicament chamber and having second position for directing
medicament from the medicament chamber to the injector nozzle; a
container holder apparatus including: a retainer member having
flexible fingers formed in a closed curve thereon and directed away
from the injector body to define a chamber for receiving a portion
of the medicament container, third means for mounting the retainer
member to the injector body, and fourth means for flexing the
fingers inwardly to securely grasp a portion of the medicament
container placed within the chamber defined by the flexible fingers
of the retainer member; and fifth means for providing air
communication from the atmosphere to any
2. The apparatus of claim 1 wherein the means for flexing the
fingers is a retainer ring in the form of a cap-like member
including a top portion, side walls, and an aperture defined by
radially outwardly inclined side walls projecting downwardly from
the top portion toward the injector body from the aperture such
that the aperture side walls ride on the outer surface of the
fingers of the retainer member to cause the fingers to flex and
grip a portion of the medicament container when the retainer ring
is moved towards the injector body to thereby securely mount the
container to
3. The apparatus of claim 2 wherein the thickness of the flexible
fingers increases as the distance from the fingers to the injector
body decreases to form an outwardly inclined outer surface on the
fingers such that the inclined side walls of the aperture of the
retainer ring ride on the
4. The apparatus of claim 3 wherein the retainer ring is threadably
connected to the injector body to thereby allow positioning of
the
5. Apparatus for providing jet injection of medicament for use in
combination with medicament stored in medicament containers
comprising, in combination: an injector body; an injector nozzle on
one end of the injector body; a medicament chamber located within
the injector body for receiving appropriate dosages of medicament;
first means for selectively changing the volume of the medicament
chamber to cause suction of medicament therein and expulsion of
medicament therefrom; medicament container holder apparatus,
including: a retainer member having flexible fingers formed in a
closed curve thereon and directed away from the injector body to
define a chamber arranged to receive a portion of the medicament
container, second means for mounting the retainer member to the
injector body, and third means for flexing the fingers inwardly to
securely grasp a portion of the medicament container placed within
the chamber defined by the flexible fingers of the retainer member;
fourth means for receiving medicament from any medicament container
within the medicament container holder apparatus; fifth means for
providing air communication to any medicament container within the
medicament container holder apparatus; a medicament passageway for
providing medicament communication between the fourth means and the
interior of the injector body; an air passageway, at least
partially located within the injector body and having an outlet
formed in the injector body, for providing air communication
between the fifth means and the atmosphere; valve member located
within the injector body having a first position for directing
medicament from the medicament passageway to the medicament chamber
and having a second position for directing medicament from the
medicament chamber to the injector nozzle; and safety member having
a first position for interfering with the valve member for
preventing movement of the valve member from the second position of
the valve member and for simultaneously blocking the outlet of the
air passageway and having a second position for allowing movement
of the valve member from the second position of the valve member to
the first position of the valve member and for allowing
6. The apparatus of claim 1 wherein the means for flexing the
fingers is a retainer ring in the form of a cap-like member
including a top portion, side walls, and an aperture defined by
radially outwardly inclined side walls projecting downwardly from
the top portion toward the injector body from the aperture such
that the aperture side walls ride on the outer surface of the
fingers of the retainer member to cause the fingers to flex and
grip a portion of the medicament container when the retainer ring
is moved towards the injector body to thereby securely mount the
container to
7. The apparatus of claim 1 wherein the valve member is a slide
shuttle valve including two passageways, one of the passageways
being substantially straight for directing medicament from the
medicament chamber to the injector nozzle and the second of the
passageways being laterally spaced from the first and having a
general shape of the letter "L" for directing medicament from the
medicament passageway to the
8. Apparatus for use in providing jet injection of medicament for
use in combination with medicament stored in containers comprising,
in combination: an injector body; an injector nozzle on one end of
the injector body; a medicament chamber within the injector body
for receiving appropriate doses of medicament; first means for
selectively changing the volume of the medicament chamber to cause
suction of medicament therein and expulsion of medicament
therefrom; second means for receiving medicament from a medicament
container; third means for providing air communication to the
medicament container; a medicament passageway for providing
medicament communication between the second means and the interior
of the injector body; an air passageway, at least partially located
within the injector body and having an outlet formed in the
injector body, for providing air communication between the third
means and the atmosphere; valve member located within the injector
body having a first position for directing medicament from the
medicament passageway to the medicament chamber and having a second
position for directing medicament from the medicament chamber to
the injector nozzle; and safety member having a first position for
interfering with the valve member for preventing movement of the
valve member from the second position of the valve member and for
simultaneously blocking the outlet of the air passageway to the
third means and having a second position for allowing movement of
the valve member from the second position of the valve member to
the first position of the valve member and for allowing air flow
into
9. The apparatus of claim 8 wherein the valve member is a slide
shuttle valve including two passageways, one of the passageways
being substantially straight for directing medicament from the
medicament clamber to the injector nozzle and the second of the
passageways being laterally spaced from the first and having a
general shape of the letter L for directing medicament from the
medicament passageway to the medicament
10. The apparatus of claim 9 wherein the safety includes a
projection that can be positioned over the end of the slide shuttle
valve such that the
11. The apparatus of claim 9 wherein means for preventing rotation
of the slide shuttle valve is provided including a slot formed in
the shuttle valve and a pin secured in the injector body and
extending into the slot
12. The apparatus of claim 11 wherein the slide shuttle valve is
selectively captured in the second position by the combination of
the means for preventing rotation, including the pin and the slot,
and the
13. The apparatus of claim 8 wherein the safety member includes, in
combination: a detent member biased towards the injector body that
can be selectively positioned within the outlet of the air
passageway to thereby block the air communication to the means for
providing air communication
14. The apparatus of claim 8 wherein the means for receiving
medicament from any medicament container and the means for
providing air communication to any medicament container are
needles.
Description
BACKGROUND
This invention relates generally to devices for injection of
medicament and more specifically to devices for injection of
medicaments through the use of jet injection.
Many people require daily amounts of medicament to combat various
illnesses, such as the daily dosages of insulin required for a
person suffering from diabetes. Thus far the majority of these
medicaments are required to be administered by daily injections.
Therefore, many people have learned to inject themselves with
medicament through the use of a common needle syringe.
Injectors of the type not utilizing a needle have been used to
overcome the undesirable characteristics of needle syringes, such
as the reluctance of some persons to self inject, scarring, and
general esthetics. With the advent of one of these needleless
devices, hypodermic jet injectors, and the increasing popularity of
their use by medical personnel and nonmedical personnel, including
children, there exists an increasing need for improved hypodermic
jet injectors.
The present invention provides such an improved device for the jet
injection of medicaments.
SUMMARY
Briefly, an injector according to a preferred embodiment of the
present invention includes: a piston slidable within a medicament
chamber; several springs, operatively connected to the piston which
may be compressed upon retraction of the piston; mechanism which
can be used to compress the springs; a trigger mechanism which can
selectively release the energy in the springs thus advancing the
piston to force the medicament from the medicament chamber and
through a control nozzle; a container mounted upon the injector to
store medicament; and a valve member which can selectively direct
the medicament from the container to the chamber.
A safety mechanism is further provided to perform a dual purpose in
that it interacts with the valve member and with the air flow to
the medicament container. In a first position, the safety blocks
the outlet of an air passageway formed in the valve body, thus
sealing the air passageway from the outside air to prevent
contamination of the medicament in the container. Simultaneously
the safety locks the valve member in the proper position to
administer medicament. In a second safety position, the safety is
moved from the outlet of the air passageway such that the interior
of the medicament container communicates with the outside air thus
enabling air to enter the medicament container and allow filling of
the medicament chamber. The second position of the safety also
allows the valve member to be moved to a position allowing fluid
communication between the medicament container and the medicament
chamber.
Thus, when the injector is to be filled, the safety is moved to a
second position and the valve member is moved to the fill position.
Medicament can then be drawn from the medicament container into the
injector and is replaced by air drawn from the atmosphere through
the open air passageway into the container. When the medicament
chamber within the injector is filled, the valve member is moved to
the position allowing injection, and the safety is moved to the
first position, thereby blocking the air passageway and preventing
movement of the valve member from the injection position.
A container holder mechanism is also provided for mounting a
medicament container on the injector. The container holder
mechanism includes a container retainer having flexible fingers
forming a chamber for receiving the pierceable cap of a medicament
container such that when the cap of the container is placed in the
chamber, the fingers may be flexed against the cap by a retainer
ring to thereby secure the container in the container holder
mechanism.
It is thus an object of the present invention to provide an
improved medicament injection device.
It is a further object of the present invention to provide such a
device of relatively simple design such that it can be used by
unskilled practitioners, including children, for injecting
themselves with medicament.
It is a further object of the present invention to provide such a
device that may be manufactured at a relatively low cost.
It is a further object of the present invention to provide such a
device having an improved container holder for securely mounting a
medicament container thereon.
It is a further object of the present invention to provide such a
device having a dual purpose safety to control movement of a valve
member and simultaneously control air communication to the
medicament container.
These and further objects and advantages of the present invention
will become clearer in the light of the following detailed
description of an illustrative embodiment of this invention
described in connection with the drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial perspective view of an injection device
according to the present invention.
FIG. 2 is a partial sectional view of the injection device of FIG.
1 according to section line 2--2 of FIG 1.
FIG. 3 is a partial front view of the injection device of FIG.
1.
FIG. 4 is a further partial sectional view of the injection device
of FIG. 1 according to the section line 4--4 of FIG. 2.
FIG. 5 is a further partial sectional view of the injection device
of FIG. 1 according to the section line 5--5 in FIG. 4.
FIG. 6 is a further partial sectional view of the injection device
of FIG. 1 according to the section line 6--6 in FIG. 3.
FIG. 7 is a further partial sectional view of the injection device
of FIG. 1 according to the section line 7--7 of FIG. 5.
FIG. 8 is a partial, exploded perspective view of the container
holder mechanism of the injection device of FIG. 1.
DESCRIPTION
Referring to the drawings, a device for the injection of medicament
is shown and generally indicated as 10. Injector 10 includes an
injector body 12, shown in fragmentary form, a valve body 14, a
container holder mechanism 16, and a nozzle 18. Body 12 contains
the mechanism necessary for selectively changing the volume of a
medicament chamber 22 to cause suction of medicament therein and
expulsion of medicament therefrom.
The mechanism includes compressible springs, not shown, operatively
connected to a piston 20 such that the springs can be compressed in
retracting piston 20 in medicament chamber 22. A suitable trigger
mechanism, not shown, is provided to selectively release the energy
stored in the springs thus advancing piston 20 to cause expulsion
of medicament from chamber 22 and through injector nozzle 18.
Suitable means for compressing the springs may be of the hand
wind-up type as illustrated in U.S. Pat. No. 2,754,818, or the
pressurized fluid type as illustrated in U.S. Pat. No. 3,130,723,
or others.
Container holder mechanism 16 includes a container support member
24 and a container holding apparatus 26. Container support member
24 includes an irregularly shaped body 31 which terminates, at its
opposite ends, in surfaces 32 and 34, the planes of which are
arranged at a relatively acute angle with respect to one another.
Counter bores 28 and 30 are formed in body 31 to allow the
admittance of screws 36 to secure surface 34 of body 31 of
container support member 24 onto a top surface 40 of valve body
14.
Container holding apparatus 26 includes a container retainer 42, a
retainer ring 44, and a needle base 46. Container retainer 42 is a
cup-shaped member including a flat annular base 47 including lower
and upper surfaces 48 and 50, respectively. Spaced flexible fingers
52 project upwardly from the inside periphery 53 of cup-shaped
container 49 of container retainer 42 to form a generally
cylindrical chamber 67. Threads 54 are located on the outside
periphery 55 of container retainer 42.
A finger flexing member 44 is shown in its preferred form as a
retainer ring. Retainer ring 44 is a cap-like member having
integral, internally threaded, cylindrical side walls 58. A
centrally positioned aperture 56 is defined by radially outwardly
inclined side walls 60 projecting downward from the top of ring
44.
Intake needle base 46 is located in the hollow, cup-like portion 49
of container retainer 42 and has counter bores 62 into which screws
64 may pass. The screws 64 extend through intake needle base 46,
through surfaces 50 and 48 of container retainer 42 and through
surface 32 into body 31 of container support member 24 thus
mounting the container holding apparatus 26 to the container
support member 24. A suitable pad 65 can be provided to cover the
counter bores 62 and also act as abutment means for the container
70. Also, a suitable bushing, not shown, may also be added between
surfaces 32 and 48.
Fingers 52 have generally straight, smooth inside surfaces 66
forming a generally cylindrical chamber 67. The thickness of
fingers 52 increases towards the intake needle base 46 to provide a
sloped surface 68 on the exterior of the outermost portions of
fingers 52. When retainer ring 44 is screwed on threads 54 of
container retainer 42, inclined sides 60 of aperture 56 of ring 44
engage sloped exterior sides 68 of fingers 52 such that fingers 56
are caused to flex inwardly towards the center of chamber 67. When
a pierceable cap 72 of a suitable bottle or similar container 70 is
inserted through aperture 56 into cylindrical chamber 67 formed by
fingers 52, container 70 is releasably secured onto container
holder mechanism 16 by threading retainer ring 44 on container
retainer 42 such that ring 44 flexes fingers 52 to securely grasp
pierceable cap 72, as best seen in FIG. 2.
To receive fluid communication and to provide air communication to
the medicament container 70 a needle assembly 74 is provided.
Needle assembly 74 passes through container retainer 42 and intake
needle base 46 and through pierceable cap 72 of any container 70 in
container holder mechanism 16 to the interior of container 70.
Needle assembly 74 contains a diametrically larger, elongated,
hollow, cylindrical needle 76 and a diametrically smaller, longer
length, hollow, elongated cylindrical needle 78 concentrically
arranged within needle 76 to leave an annular space 80 surrounding
needle 76 to allow the medicament from container 70 to enter the
hollow interior of needle 76. A notch 82 may be provided in needle
76 to allow medicament to enter needle 76 at a higher rate or to
allow a more certain entry.
As best seen in FIG. 4, container support member 24 includes spaced
parallel passageways 84 and 86 that lead from container retainer
element 26 to the interior of container support member 24.
Passageway 84 has a larger cross-sectional area than passageway 86
so that it can accommodate liquid flow while passageway 86
accommodates the required air flow. Needle assembly 74 extends into
a fluid chamber 88 formed in intake needle base 46, as best seen in
FIGS. 4 and 5.
As best seen in FIG. 4, needle 76 includes a removed section 90
located in fluid chamber 88 allowing needle 78 to be bent and
positioned in passageway 86. Sealing means 92, for example an
O-ring, may be provided to prevent liquid from entering passageway
86 from fluid chamber 88. The lower portion of needle 76 extends
through intake needle base 46 and into passageway 84 in container
retainer 42. Sealing means 89, for example an O-ring, is provided
to prevent liquid from leaking from fluid chamber 88 to chamber
67.
Passageways 94 and 96 intersect with passageways 86 and 84,
respectively, as seen in FIGS. 5 and 2, to provide fluid
communication with valve body 14 such that the outlets of
passageways 94 and 96 at the upper surface of valve body 14 are in
a longitudinally spaced relation along valve body 14.
Valve body 14 includes a valve member 98, shown in its preferred
form as a slide shuttle valve, and a safety 104. As can best be
seen in FIG. 6, a pin 108 extends from the injector body into a
slot or groove 106 in slide shuttle valve 98 to prevent axial
rotation of shuttle valve 98 with respect to the valve body 14. The
length of slot 106 also determines how far shuttle valve 98 may
longitudinally slide, therefore the length of the slot 106 is such
that the valve is in a predetermined position when pin 108 abuts
against the ends of groove 106 to thus form lateral stops for valve
98. Pin 108 is held in position by a bore 109 in valve body 14 and
also the back wall of nozzle 18.
Medicament chamber 22 formed in injector 10 narrows at its forward
end into a passage 110 that extends through valve body 14 to slide
shuttle valve 98. Slide shuttle valve 98 contains two laterally
spaced passageways 100 and 102, with passageway 100 generally
straight and passageway 102 formed of two further perpendicularly
meeting passageways 103 and 105 defined within the body of valve 98
to form the shape of the letter "L". Two suitable sealing means
112, for example O-rings, quad rings, or the like, are provided on
shuttle valve 98 to prevent fluid from leaking from valve body
14.
As best seen in FIG. 2, valve body 14 also includes passageway 114
which extends from the shuttle valve 98 to nozzle 18, passageway
116 which extends from container holder mechanism 16 to shuttle
valve 98, and passageway 118, best seen in FIG. 5 which extends
from container holder mechanism 16 to a point in a spaced relation
from shuttle valve 98. Suitable sealing means 120, such as for
example O-rings, are provided in passageways 114 and 118 to prevent
fluid leakage.
A check valve 125 is also provided in passageway 116 to prevent
back flow of medicament through passageway 116 to container 70.
Cooperating with valve 125 is an O-ring 123 to provide suitable
sealing between surfaces 34 and 40 and the check valve 125. A check
valve bushing, not shown, can be provided to prevent O-ring 123
from protruding around the top of check valve 125. A filter screen,
not shown, may be inserted above O-ring 123 adjacent surfaces 34
and 40 to filter the medicament passing from passageway 96 to
passageway 116.
As best seen in FIGS. 6 and 7 safety 104 includes a slide portion
128 adapted to move in a slot 130 provided in valve body 14 and a
longitudinally projecting portion 126 having a flat bottom wall
132. Slide portion 128 also includes a detent ball 124 which is
biased against valve body 14 by a spring 122. As can be best seen
in FIG. 6, a detent hole 134 is provided in the bottom of the slot
130 in the valve body 14. A passageway 119, the diameter of which
is less that that of ball 124, intersects with passageway 118 and
has an outlet 121 that is longitudinally spaced from detent hole
134 towards nozzle 18.
Slide portion 128 of safety 104 includes a necked portion 138, best
seen in FIG. 7, that rides in the slot 130 to prevent safety 104
from disengaging from valve body 14. Also, as slot 130 abuts body
12, safety 104 is prevented from sliding out of the end of slot
130. Removed portions 136 may be provided in the top portion of
safety 104 to provide finger gripping means.
Safety 104 may be placed in either of two general positions, an ON
or an OFF position. In the OFF position, not shown, safety 104 is
placed in a rearmost position away from nozzle 18 such that ball
124 is captured by the detent 134 and the projecting portion 126 is
located rearward of the end of the periphery of shuttle valve 98.
In the ON position, as best seen in FIG. 6, safety 104 is in a
forward position such that ball 124 is located in outlet 121 of
passageway 119 such that ball 124 blocks outlet 121. When the
safety 104 is located in its forward or ON position surface 132 of
projection 126 extends over the end of the shuttle valve 98.
Slide shuttle valve 98 may be placed in either of two positions, a
fill position or a fire position, in cooperation with safety 104.
When valve 98 is in the fill position, not shown, passageway 105 of
passage 102 is in fluid communication with passageway 110 in the
valve body 14 such that medicament chamber 22 is in fluid
communication with the interior of container 70 through passageways
110, 102, 116, 96, and 84 and needle 76. When valve 98 is in the
fire position, shown in FIG. 6, medicament chamber 22 is in direct
fluid communication with nozzle 18 through passageways 110, 100,
and 114.
OPERATION
In operation the device 10 is used for administering medicament to
a patient without the use of needles. This is done by first causing
the injection of a small amount of medicament at extremely large
velocities such that it punctures the skin and then injecting the
remaining medicament into the body through this puncture. The
technique is explained in U.S. Pat. No. 2,704,542 and others.
For the sake of explanation, assume that the injector 10 has just
been fired, that shuttle valve 98 is in the fire position, that
safety 104 is in the ON position, and that piston 20 is in its
advanced position.
A container 70 containing the desired medicament and having a
pierceable cap 72 of a suitable diameter such that it will fit into
cylindrical chamber 67 is found. Retainer ring 44 is then unscrewed
to an upper position on container retainer 42 away from retainer
42. Container 70 is then first positioned centrally of and over
aperture 56 such that needle assembly 78 can begin to puncture the
pierceable cap 72 and extend into the interior of the container 70.
Container 70 is then pushed through aperture 56 of retainer ring 44
until it contacts pad 65. Retainer ring 44 is then screwed down on
container retainer 42 causing the inclined side walls 60 of
aperture 56 of the retainer ring 44 to engage the sloped back sides
68 of fingers 52. Fingers 52 are thereby flexed towards cap 72 to
grasp and retain the cap 72.
With the safety 104 in the assumed ON position, surface 132 thereof
extends over the end of shuttle valve 98 such that, in combination
with the groove 106 an the pin 108, shuttle valve 98 is rigidly
held in the fire position within body 14. With safety 104 in the ON
position, as explained, ball 124 is positioned in outlet 121 of
passageway 119 thereby sealing the air passage to the interior of
container 70. Thus the safetey 104 simultaneously prevents
accidental movement of valve 98 from the fire position and blocks
air communication to the container 70 in the fire position. When
the injector 10 is to be filled, safety 104 is moved longitudinally
rearward, away from nozzle 18, to the OFF position such that ball
124 falls into detent 134. Thus, air may pass around the forward
projecting portion 126 into slot 130, through passageways 119, 118,
94, 86, and needle 78, thereby providing fluid communication
between the interior of container 70 and the atmosphere.
At this time shuttle valve 98 can be laterally moved into the fill
position. The valve 98 is then laterally pushed from the position
shown in FIG. 6 until pin 108 abuts the opposite end of slot 106.
When in the fill position, passageway 102 aligns with passageways
110 and 116 such that medicament chamber 22 is in continuous fluid
communication with container 70. Medicament then enters needle 76
through the annular space 80, or notch 82, or both, flows through
needle 76 to fluid chamber 88 in intake needle base 86, flows into
and through passageways 84 and 96 of container support member 24,
into and through passageway 116, and into and through passageway
102 of shuttle valve 98. Passageway 102 will then direct the fluid
into passageway 110 and into medicament chamber 22.
The piston 20 of medicament chamber 22 is then retracted by the
mechanism in body 12 such that medicament chamber 22 increases in
volume. This increase in volume places medicament chamber 22 under
a slight vacuum condition such that medicament from container 70 is
sucked into medicament chamber 22 as piston 20 is retracted. The
medicament that flows out of container 70 is then replaced by air
drawn into needle 78 from outlet 121.
After piston 20 has been retracted to its desired position, such
that the volume of medicament chamber 22 is equal to the dosage of
medicament desired, valve 98 is laterally moved back to the
position shown in FIG. 6 or until pin 108 abuts an end of slot 106
where it is in the fire position again. At this time, slide 128 of
safety 104 is moved forward, toward nozzle 18 and back into the ON
position thus capturing valve 98 in the fire position.
When safety 104 is in the ON position, ball 124 again blocks outlet
121 of passageway 119. Thus the interior of container 70 is cut off
from the outside air so that the air cannot contaminate the
medicament inside container 70. Thus the only time the contents of
container 70 is allowed to communicate with the air is when safety
104 is in the OFF position, or more particularly, when chamber 22
is being filled with medicament. Thus the present injector does not
require a filter placed in the air passageway into container 70 as
is commonly done in the art.
When safety 104 is in the ON position, valve 98 is rigidly fixed by
abutting portion 126 and pin 108 in the fire position. This
prevents accidental movement of valve 98 from the fire position
before or during inoculation. Since during inoculation injector 10
is prone to slide over the surface of the skin if not held
securely, injector 10 is commonly held by the hands of the operator
near valve body 14. When held in this position, valve 98 would be
susceptible to accidental sliding if a safety means of some sort
were not provided.
It may now be appreciated that use of such a safety as disclosed
herein prevents the accidental sliding of valve 98 and the blockage
of the air passageway to container holder mechanism 16 in a very
simple manner. Safety 104 is so constructed and arranged such that
its assembly time is short and its parts are few in number. The
simplicity of design also lends itself towards the use of such an
injector by individuals not trained in the medical arts.
Owing to the simple design and the small number of parts, an
injector embodying the present invention lends itself toward
disassembly, cleaning, and assembly without the need of any special
tools, technical skill, or special training.
Thus since the invention disclosed herein may be embodied in other
specific forms without departing from the spirit or general
characteristics therein, some of which forms have been indicated,
the embodiments described herein, are to be considered in all
respects illustrative and not restrictive. The scope of the
invention is indicated by the appended claims rather than by the
foregoing description, and all changes which come within meaning
and range of the equivalency of the claims are intended to be
embraced therein.
* * * * *