Note: Descriptions are shown in the official language in which they were submitted.
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HYPODERMIC INJECTION'~YSTEM
BACKGROUND OF THE INVENTION
Cross Reference to Related Application
This application claims priority of U.S. Provisional Application
No.60/126,062,
filed March 25, 1999, under Title 35, United States Code, Section 119(e).
Field of the Invention
This invention relates to hypodermic injection systems, and more particularly
to
injection systems wherein the injectate is held in containers, and the system
discharges
the injectate from the containers. The invention fords particular use as a
mufti-channel
injection system.
Description of the Prior Art
Hypodermic injection systems are widely used throughout the world today, both
with respect to humans and with respect to animals. Moreover, there are many
situations
when multiple injections made simultaneously are either required or would be
helpful.
Sometimes, different materials can be injected (often referred to herein as
"injectates")
for protecting against a variety of diseases, for serving as components for a
single
disease, for providing added health benefits to humans or animals, such as by
way of
added vitamins, minerals, etc., or to provide improved characteristics, such
as to cause
cattle to provide more milk, to enhance their growth, or to deliver
immunopharmaceutical compounds to inhibit the reproductive system in food
producing
animals, or a particular type of medical procedure in humans. In mass
injection
programs, such as injecting vast numbers of people in third world countries or
large
numbers of animals, a considerable amount of time could be saved if multiple
injections
could be made simultaneously rather than sequentially. Although there are many
advantages in simultaneous multiple injections, for example, in the case of
young
children whose vaccination schedules call for four or more injections during a
single
office visit, it would be a great advantage to deliver all of the vaccines in
a single event
to sharply limit the mental trauma that often occurs. In addition, there is
the constant
danger of needle sticks to the doctor, nurse or other person giving the
injection, and the
threat of disease, such as HIV and AIDS, which should be avoided.
For injection systems which are used to give many injections, such as to large
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groups of people or large numbers of animals, the system is necessarily slowed
down if
individual proper doses of injectate must be loaded into the injection system
or if
preloaded injectate containers must be manually or otherwise slowly loaded and
then
placed into the injection system. There is a major need for injection systems,
particularly
multiple injection systems, which can quickly and efficiently have proper
doses of the
injectate loaded into the system, the injection process made, and the system
reloaded
quickly to continue the injection process. There is likewise a great need for
the
foregoing type of systems which avoids needle sticks to the person making the
injection
and to avoid contact with either the injectate or the injecting portion of the
system by any
individual during or following the injection process.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a hypodermic injection system
for providing injectate from containers holding the injectate in an efficient
and safe
manner.
An object of the present invention is to provide a hypodermic injection system
for avoiding needle sticks in the person administering the injection.
Another object of the present is to provide an injection system for
simultaneously
providing at least two injections, and further including means for preventing
needle
sticks to persons who are not supposed to be injected.
It is yet another object of the present invention to provide an injection
system
wherein the injectate is held in cartridges having injection orifices through
which the
injectate passes and enters the desired body.
It is an additional object of the present invention to provide an injection
system
for administering injectate from at least two cartridges.
Yet another object is to provide an injection system for providing injectate
from
at least two cartridges under jet pressure through injection orifices in each
of the
cartridges.
Another object of the present invention is to provide an injection system
having
at least two cartridges with perforators through which the injectate flows.
Another object of the present invention is to provide an injection system
having
energy storage means for energizing the system to make the injection, and a
motor
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operable system for re-energizing the system in a fast and economical manner.
It is yet another object of the present invention to provide a cartridge
injection
system having biasing means for forcing injectate from at least one cartridge
into a body,
where the biasing means is placed in a cocked condition by an electric motor.
It is a related object of the present invention to provide a motor-operated
injection system wherein the electric motor is held in a handle for the
injection system.
Yet still another object of the present invention is to provide an injection
system
having biasing means for urging injectate from a cartridge into a body, and a
loading
station for energizing the biasing means in a fast and economical manner.
Another object of the present invention is to provide a hypodermic injection
system having a container holding member for holding injectate containers, the
holding
member with the container members being disposable after an injection without
requiring any physical contact or handling of the disposable portion by the
user.
Another object of the present invention is to provide a hypodermic injection
system for simultaneously injecting injectate from at least two cartridges,
the cartridges
being disposable after an injection without any physical contact or handling
of the
disposable portion by the user.
Another object of the present invention is to provide an injection system for
injecting fluid from at least one cartridge, the system having guard walls for
preventing
splashing of the injectate during the injection process.
A further object of the present invention is to provide a hypodermic injection
system for injecting injectate from at least one cartridge, the cartridges)
being held in
position by a disposable front plate.
Another object of the present invention is to provide a mufti-cartridge
injection
system with one or more springs for applying pressure to the cartridges to
dispense the
injectate, and a latching apparatus for cocking and releasing the spring(s).
Yet a further object of the present invention is to provide a mufti-channel
injection system wherein the injection means are provided in close proximity
to enable
multiple mufti-channel injections safely and effectively.
Another object of the present invention is to provide an injection cartridge,
the
cartridge having a dispensing end with an orifice or perforator through which
the
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injectate can be dispensed, and a movable plunger in the cartridge which can
be moved
into the injectate-holding portion of the cartridge to effect the dispensing
of the injectate.
An additional object of the invention is to provide an injection cartridge for
holding at least two components of an injection dosage.
A further object of the present invention is to provide an injection system
for a
plurality of cartridges, the cartridges having plungers for dispensing the
injection
injectate in the cartridges, the injection system further having a carriage
with rams for
moving towards the plungers to drive the injectate from the cartridges, and
means for
resetting the carriage in a cocked position.
It is yet another object of the present invention to provide a hypodermic
injection
system for dispensing injectate from at least one cartridge, the system having
biasing
means which is placed and held in the cocked position in accordance with a
sensing
signal indicating whether or not a cartridge is loaded in the system.
It is a general object of the present invention to provide an improved
hypodermic
injection system which can be used for one or more injections at the same
time, which is
economical and fast to use with a large number of people or animals, which
prevents
inadvertent needle sticks, and which prevents user contact with potentially
contaminated
surfaces following an injection procedure..
Other objects and advantages will become apparent to those skilled in the art
from the description to follow and from the appended claims.
The foregoing objects are achieved according to the preferred embodiment of
the
invention. In one preferred embodiment, a jet hypodermic injection system is
provided
for holding at least one cartridge for holding a serum, a vaccine or other
injectate. The
cartridge preferably has a dispensing end with an end portion having a channel
with an
exit nozzle being an orifice. A plunger is provided in the cartridge, and an
injectate is
disposed between the plunger and the end portion. The end portion could
alternatively
have a perforator rather than an orifice for the exit nozzle. The system
includes a
housing having a disposable front end plate with holes having holding surfaces
for
holding the forward end of the cartridges. The housing houses a movable
carriage with
rams for moving the plungers through the respective cartridges. The carriage
is movable
between a set position and a dispensing position. One or more springs move or
drive the
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carriage from its set position, wherein the springs are in a cocked position,
to a
dispensing position wherein the carriage carries the rams for moving the
respective
plungers through the cartridges to force injectate through the respective
channels and exit
nozzles into the body being injected. The springs) are held in a cocked
position by a
releasable latch, which could be a solenoid piston which is actuated when a
cartridge
sensor emits a signal to the solenoid according to whether a cartridge or
cartridges are
loaded in the housing.
The carnage, in a preferred embodiment, is moved from its dispensing position
to its set position, and for setting the springs) to their cocked condition,
by a motor
driven cam. A cam follower extends from the carriage, and the motor rotates
the cam
which moves the cam follower, and hence the carriage, to the set or cocked
position.
The springs) are preferably guided and positioned by movable rods which
extend between the carriage and the rear part of the housing through which
they extend.
A fixed member on the rods) defines a shoulder for supporting one end of the
spring(s);
the other end of the springs) engages the inner part of the rear wall of the
housing. As
the carriage moves towards the set position, it moves the respective rods and
compresses
the springs) to their cocked position.
The front plate for holding the respective cartridges is ::.;ectable or
catapulted
away from the injector after the cartridges have been used, and the plate with
the spent
cartridges are thereby disposed. This avoids the problems of needle sticks or
any contact
with contaminated surfaces by the doctor, nurses or other health care workers
administering the injection, and also precludes unsafe and illegal use of
spent cartridges.
In a preferred embodiment, the cam or other carriage resetting apparatus is
moved from the final position to an initial position by means of a motor
having a motor
driven tool designed for rotating the cam or other apparatus. A loading
station can be
provided for resetting the cams of one or more injection systems according to
the
invention, which is preferably done when new cartridges) are to be loaded in
the system.
Alternatively, the housing can be held with a handle designed to carry the
motor and
possibly a power source for the motor. The system is ideally suited for
injecting large
masses of people or animals in a safe and fast manner, providing individual or
multiple
inj ections.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a pictorial view of a hypodermic injection system of the invention
showing a front end with all six injectate cartridges having orifices for the
exit nozzles;
Figure 2 is a pictorial view of the system illustrated in Figure 1, showing
the
release and disposal of a used front end portion of the system;
Figure 3 is a pictorial view of the disposable front end of the preferred
embodiment of the invention;
Figure 4 is a pictorial view of the front end of the invention showing the
center
two cartridges having orifices loaded in the front end and the four outer
cartridge
locations having dummy loads;
Figure 5 is a pictorial view of an embodiment of the invention showing the two
center cartridges having perforators, and the four outer cartridge locations
having dummy
loads;
Figure 6 is a transparent pictorial view of a cartridge according to the
invention;
Figure 7 is a cross-sectional view of the preferred embodiment of the energy
storage part of the system shown in Figure 1;
Figure 8 is a pictorial view of another preferred embodiment of the invention
showing a loading station for cocking the energy storage part of the system;
Figure 9 is a pictorial view of the rear portion of the embodiment shown in
Figure 8; and
Figures 10-12 are schematic views of dispensing portions for a six-channel
injection system according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figures l and 2, a preferred embodiment of the invention is
shown.
These figures show a hypodermic injection system 1 having a housing 3 and a
handle 5.
Housing 3 includes a front end or plate 7 having an injection trigger 9 and a
front end
release trigger 11. Trigger 9 can be in the form of a rotatable lever, whereas
trigger 11
can be a depressible button. System 1 is shown for delivering six simultaneous
injections as described below, although the number can be from one to N (i.e.,
any
number of injections).
Referring specifically to Figure 2, an important advantage of the present
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invention is the ease of disposability of the front end with the expended
cartridges to
avoid inadvertent touching of the injection portion of the system and, if
perforators or
nozzles are used for the exit nozzles, the possibility of inadvertent needle
sticks by the
user. This easily precludes cross-contamination and disease from both blood
and the
injectate on the front end of the injection system. Figure 2 shows injection
system 1
following an injection. Front plate 7 is one version of a holding member for
holding
cartridges 13. Prior to an injection, front plate 7 holding cartridges 13 is
releasably
locked in housing 3 as shown in Figure 1. As explained in further detail
below, the
cartridges each hold a required dose of an injectate, which often is a serum
or a vaccine.
The front part of cartridges 13 are held in front plate 7, and a rearwardly
part of the
cartridges are supported and held in a holding fixture 1 S.
After an injection has been given from the cartridges loaded in system 1, the
user
actuates front end trigger 11 which withdraws locking members 17 which have
entered
grooves 19 in front plate 7, and which further releases the springs located in
the mating
holes at position 21 to exert a spring force urging front end 7 with
cartridges 13
forwardly away from housing 3, to catapult these parts from housing 3 for
disposal, such
as into a container B designed to hold contaminated goods. No person or animal
touches
front plate 7 or cartridges 13 following the injection process and during the
disposal of
front plate 7.
Front plate 7 is shown in further detail in Figure 3. As explained earlier,
front
plate 7 is one of many possible devices for holding the injectate containers,
such as
cartridges 13. Front plate 7 includes an external front surface 23 and a
rearwardly
extending portion 25 into the opposite sides of which are provided grooves 19.
Front
plate 7 can be slid into place and grabbed by locking members 17 near the
front of
housing 3, which are received in grooves 19, these members 17 being withdrawn
upon
the actuation of trigger 11. Alternatively, locking slides or the like can be
removably
inserted into grooves 19 to lock front plate 7 to housing 3 (of which the
front end forms a
part), the front plate being ejectable from the remainder of housing 3 once
the locking
members 17 are removed from grooves 19. Front end 7 further has holes 29 with
holding surfaces 31 for gripping the forward ends of cartridges 13 which are
preferably
press fit into holes 29 to hold the cartridges in place. The outer surfaces of
cartridge 13
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can have a high friction surface if necessary, to assure a firm grip. Guard
rings 33 are
provided around each of holes 29 in order to prevent the splashing of blood or
of
injectate as it flows through the exit nozzle of cartridge 13, particularly
during the
injection process. An additional splash ring 35 can also be provided, as shown
in Figure
2, to add more protection against splashing.
Front plate 7 or other holding members are disposable as explained above. In
order to maintain the sterility of the front end, it is provided in a package
for keeping the
front end sterile. Sterile packaged cartridges can be filled at the site of
the injection
procedure, or they can be delivered already filled with the selected vaccines
ready for
insertion into front plate 7. Alternatively, the front end can be provided
with cartridges
previously inserted and filled with the proper dosage of the respective
injectate to be
contained therein, all of which would be provided in the sterile package of
the front end
in which they are being gripped. It should be noted that front end 7 could
hold one
cartridge, six as shown, or indeed any number of cartridges. For various
practical
reasons as discussed below, it is anticipated that no more than six injections
would be
simultaneously given.
Figure 4 shows front plate 7 with six cartridges 13 loaded therein. It is not
necessary that all cartridge locations contain dispensable injectate. Thus, as
explained
earlier, plate 7 has rearwardly extending portion 25 and opposed side grooves
19. Plate 7
could be slid behind removable locking members 17 which would extend into
grooves
19 and would be removed when front plate 7 and cartridges 13 are ejected or
catapulted
from housing 3. Referring to the front portion of cartridge 13, an orifice 35
is the exit
portion for the two active channels shown in Figure 4 and they extend through
the
forward portion of cartridge 13. The orifice is so designed that, in the
preferred
embodiment of the invention, it defines the path for the jet flow of the
injectate from
cartridge 13. Orifice 35 could be replaced with a perforator, such as
perforators on the
order of 0.5 to 1.0 mm in length, as disclosed in U.S. patent application
Serial No.
08/738,303, as shown as perforators 36 in Figure 5. The use of perforators
would allow
for lower injection pressures and a reduction, if not the total elimination,
in the amount
of injectate fluid remaining on the surface following an injection.
Experimental
programs by the inventors have shown that perforators would sometime improve
the
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efficacy and also reduce impact trauma to the patient.
As explained earlier, six cartridge locations are shown. It was explained that
any
number of cartridges with respective injection channels could be provided.
However,
the protocol suggested by the Center for Disease Control (CDC) limits the
number of
childhood injections to a maximum of four during a single visit to a health
care facility.
The CDC apparently feels that the number of suggested injections during an
office visit
might increase as more vaccines become available. The size of the patient, and
the
location of the injection site on the body, will limit the volume of fluid
that can be
realistically delivered to an injection site. This factor will no doubt be
different for
children, adolescents and adults, for example, military personnel (who often
require
multiple vaccinations when entering the service or being deployed to different
regions of
the world.
As in Figure 4, the apparatus shown in Figure 5 need not have all cartridges
containing dispensable injectate. Other cartridges, such as inactive or dummy
load
cartridges, could be used lacking injectate at those channels. Such inactive
cartridges
could be coded, such as with different colors. In this case, Figure 5 shows
perforators 36
at the active channels, and dummy cartridges 37 at the inactive channels.
Figure 6 shows an injectate container in its preferred form as cartridge 13.
Cartridge 13 has an outer wall 38 and an inner wall 39 which defines a tube
41. Slidable
into tube 41 is a plunger 43 with a seal at its outer circumference to prevent
leakage out
the back end and which can be made from an elastomeric material, such as a
rubber-like
compound, plastic or even glass, but with a rubber seal. Plunger 43 is
dimensioned to
engage inner wall 39 in a fluid-tight manner. Plunger 43 can have two wall-
engaging
cylindrical portions 45 (towards the front) and 47 (towards the rear) to
further discourage
leakage during an injection. Plunger 43 defines an injectate-holding portion
49 of
cartridge 13, between plunger 43 and a forward part 51 of cartridge 13 having
a channel
53 which terminates in orifice 35. The portion of cartridge 13 at its forward
end has a
smaller diameter than does the rearward part, and is preferably press fit into
front plate 7
as explained earlier. The rear part of front plate 7 preferably engages a
shoulder 55 when
cartridge 13 is press fit into plate 7.
Cartridge 13 could be filled on-site or could be filled off site, depending on
the
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circumstances. Furthermore, cartridges 13 could be preloaded into the holding
member
such as front plate 7 at the site where the system is to be used, or it can be
done off site.
When done off site, the cartridge could be filled and sent to the loading
facility
separately from the front plate, or they could be preloaded into the front
plate (or other
holding member) and provided in a sterile package.
Cartridges 13 could be designed for lyophilized vaccine by providing two
compartments that are separated by an easily rupturable seal, such as seals 56
shown in
dotted lines. One compartment would contain the lyophilized vaccine,
medication or
serum, and the adjoining compartment would contain the correct amount of fluid
for
mixing it. Means could also be provided for rupturing the seal and mixing the
ingredients together when a cartridge is inserted into front plate 7 or when
the cartridge-
laden plate is inserted into the injector. A means of mixing lyophilized
vaccines in the
cartridge at the time of injection is described in U.S. Patent No. 5,080,648.
Turning next to Figure 7, which is a cut-away view of system 1 without the
handle or triggers discussed earlier. System 1 has housing 3 and end plate 7,
as
explained earlier. To avoid undue complexity in Figure 7, the means for
ejecting or
catapulting front plate 7 away from the injector are not shown. Housing 3
houses a
carriage 57 which has extending from it rams or plunger rods 59. A set of
three springs
61 (for each of the three cartridges shown, there being six cartridges and
springs in
system 1 ) extend around the set of drive rods 63, each of which having nuts
or movable
spring supports 65. Supports 65 are movable along threaded rods 63 to provide
a means
to adjust spring preload and, therefore, injection pressure. Housing 3 has a
rear wall 67,
and springs 61 have their rear ends in contact with stationary wall 67. A set
of holes 69
are provided in wall 67 through which rods 63 pass and are movable. A cap or
shoulder
71 is provided at the rear end of rod 63 for both preventing rod 63 from
entering the
inside chamber of housing 3 and for cooperating with a latching assembly
discussed
below. The latching assembly includes a solenoid 73 for each spring (however,
only two
are shown) and each having pistons 75 which in their energized state are
inserted in front
of caps 71 as part of the latching assembly. A cartridge sensor switch 79 is
closed when
a cartridge is installed in the appropriate holding portion of housing 3,
thereby retracting
piston 75 away from the path of moving rod 63 and cap 71. This is illustrated
in the
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upper position of Figure 7.
A cam 81 rotatably mounted on a shaft or axle 83 is provided for resetting
carriage assembly 57 as explained below. A cam follower 85 having follower arm
87
connected to carriage assembly 57 and a roller 89 which follows the contour of
cam 81.
Figure 7 shows two cartridges 13 loaded in the two upper chambers 88 of the
system, and no cartridge is included in bottom cartridge chamber 88. The two
cartridges
have plungers 43. Front plate 7 has guard rings 33 as discussed earlier.
Figure 7 shows injection system 1 after an injection has been made. Carriage
57
is in its dispensed position, having been moved all the way to the right to
the front of
housing 3. Rams 60 have pushed plungers 43 to the forward end of cartridges 13
to
discharge the injectate from the two active cartridges during the injection
process. In
order to reload housing 3, shaft 83 and cam 81 are rotated clockwise by a
motor (as
discussed below) causing roller 89 to roll across the periphery of cam 81 and
move cam
follower 85 and carriage 57 rearwardly to the left in Figure 7. The contour of
cam 81 is
configured to effect this movement as its radius increases at the point of
contact with
roller 89. As carriage assembly 57 is moved to the left, rods 63 are forced to
the left as
well. Nuts 65 compress springs 61 until cam 81 has completed its rotation from
an
initial position to a final position, at which time springs 61 are totally
compressed and
rods 63 are at their leftmost or rearmost position. At this time, rams or
drive rods 60 are
withdrawn from member 15 providing a convenient time to eject the used front
end away
from the injector leaving room for new cartridges having proper dosages of
injectate in
them, inserted into member 15. When cartridges 13 are properly installed, they
again
actuate switch 79, which emits a sensing signal to effect the movement of
solenoid
piston 75 away from the path of caps 71 on rods 63. Since no cartridge is
inserted in the
lower channel of Figure 7, its piston 75 is extended in front of shoulder or
cap 71, thus
preventing that spring from contributing to the injection process.
In order to commence an injection with carriage assembly 57 in its set or
cocked
position and springs 61 in their cocked position as well, the user of system 1
actuates
trigger 9. This action will either release a mechanical latch (not shown) or
will provide a
slight rotation to cam 81 to allow roller 89 to release as it moves onto the
sharp drop off
87 of cam 81.
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Springs 61 drive rods 63 forwardly to move carriage assembly 57 forwardly, and
thereby drive rams 60 against plungers 43 to force injectate through channels
51 of
cartridges 13 and out through orifices 35 (or perforators 36). After the
injection, the user
actuates trigger 1 l, causing the catapulting of front plate 7 and cartridges
13 from the
unit for disposal, such as into a barrel B.
In a related embodiment, the details of which are not shown, when injection
cartridges 13 are slid into the injection chamber, they could actuate a
connecting rod to
mechanically actuate the spring-loaded latch 75 to retract it to the non-
latched position.
There may be situations in which housing 3 is not totally loaded with
cartridges
13. In these cases, as shown in the bottom portion of Figure 7, there is no
cartridge 13 in
the lower chamber and the lower rod 63 has not been released from its cocked
or set
position. For the case where no cartridge is present when carriage 57 is first
moved to
the left, shoulder 71 is mechanically able to move past extended piston 75,
but is not able
to move past extended piston 75 when trying to move to the right unless a
cartridge is
first inserted into the channel.
In the embodiment of the invention shown in Figures l and 2, a motor and power
source are included in handle 5 for resetting cam 81 to its initial position.
A unit such as
that in Figures 1 and 2 is portable, easy to use, and particularly easy to use
for injections
for large numbers of people or large numbers of animals. Even though injector
system 1
is small, lightweight and easy to handle, in some situations it might be
advantageous to
make the hypodermic injection system according to the invention even smaller
and
lighter, when masses of people or animals are being injected, such as where a
health care
worker administers hundreds or thousands of injections over the course of a
day.
Accordingly, the preferred embodiment shown in Figures 8 and 9 form another
aspect of
the present invention.
Figure 8 shows two hypodermic injection systems 1 according to the invention,
in this case without a handle. However, a loading station 101 is provided for
putting the
carriage in its set or cocked position, and for compressing or cocking the
springs. Thus,
housing 3 houses cam 81, springs 61, and injection chambers 88 for cartridges
13, as
explained earlier. Loading station 101 has a series of walls defining
compartments 103,
105 and 107 for each receiving an injection system 1. Each compartment 103,
105, 107
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includes a drive mechanism 109 having a hexagonal shape for engaging a
corresponding
portion of cam axle 83. An enable button 111 is preferably provided so that
when a
system 1 is inserted in a compartment 103, 105, 107, button 111 is depressed
and drive
mechanism 109 rotates cam 81 to its loaded or injection ready position. The
drive
S mechanism stops rotating upon the actuation of an internal disable switch
which detects
the correct amount of rotation. These injector positions could be sensed
electronically
rather than using the button switches as shown. The hand-held portion, system
1 of
Figure 8. is then removed from station 101 for an injection to be made. The
system is
then reloaded and reset with loading station 101. While injection system 1 in
Figure 8
has the same form (less the handle) as shown in Figure 1, in an actual
commercial
system, it will have a shape that is easily held by the user when giving an
injection.
The rear portion of the apparatus shown in Fiwre 8 is shown in Figure 9.
Loading station 101 can be energized using the AC input 113 or a DC input 115.
An
on/off switch 117 is also provided. The power can be an AC grid or battery, or
can use
1 ~ compressed gas. ignitable gas such as butane, hydraulic drive, or manual
operation using
a hand crank or a foot pedal. Systems 1 shown in Figures 8 and 9 can be easily
moved
when the injection procedures are completed. Load stations 101 need not be
picked up
by the health care worker when an injection is given. Loading station 101 and
system 1
are only brought together when spring compression is needed, and this could
even be
done using a long speedometer-type cable connection instead of a direct
contact interface
as shown in Figures 8 and 9. Even though Figures 8 and 9 show DC and AC power
inputs, manual loading is also possible in case of power failure or lack of
power at a
particular location.
Although Figure 7 shows a spring for each cartridge, a single spring is also
possible. Other means for providing pressure for dispensing injectate from the
holding
members are possible. Other springs besides wire springs could be used as
well,
including resilient plastic springs, elastomeric springs such as rubber or
rubber-like
materials, and possibly electro-magnetic fields. Although the cam system shown
in
Figure 7 has been found to be effective, other means for setting the system
would also
apply. For example, there could be gearing systems. linear systems, such as
those with
linear gears, pawl and gear mechanisms, belts, rollers, and the like could be
employed.
AII~IDFD SHE'
CA 02368611 2001-09-19
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The injectate containers have been shown as being rigid, but in some
situations flexible
plastic holders might be appropriate as well.
Reference is now made to Figures 10, 11 and 12, which relate to a
configuration
analysis of the exit nozzles. The configuration of exit nozzles is
particularly important
with regard to multiple simultaneous injections which are given to a limb of a
small
child, wherein the available surface area needed to deliver an effective
injection is
limited. In addition, if multiple simultaneous injections are given, it is
preferable to
prevent or at least minimize the overlap of injectates in the child's tissue
in order to limit
the possibility of an adverse reaction if the injectates should mix in the
target tissue. In
order to achieve this non-overlap condition, the injections must be delivered
a certain
minimum distance apart. For this reason, the inventors have carried out a
geometric
analysis to determine the configuration of the exit nozzles that uses the
least amount of
surface area while still preventing overlap of the vaccines in the tissue. In
order to make
this analysis, an analysis of the volume of tissue affected by an injection
was required.
Accordingly, a six-channel system with a delivery volume of 0.2 cc for each
channel was
assumed. However, it was also noted that the standard single-shot dose is
actually 0.5
cc. It is possible that smaller doses from vaccine manufacturers may occur
with multiple
channel injections. The configurations considered by the inventors were
rectangular,
pentagonal with one orifice in the center, and hexagonal.
Pathological observation by the inventors made during the course of a U.S.
Department of Agriculture study showed that the injectate spreads very little
in the tissue
when delivered by needle and syringe; i.e., there is a pooling effect. The
research
showed that a 0.2 cc needle and syringe injection occupied a spheric volume in
the tissue
of 0.278 cc (done empirically). When an injection is given by a jet injector,
the spheric
volume of tissue affected is 8.79 times that of a needle and syringe
(empirical). Thus,
the spheric volume occupied by 0.2 cc of injectate delivered by jet injection
would be
8.79 times 0.278 cc or 2.44 cc.
The diameter of a sphere D is given by dividing the volume by 0.5236 and then
taking the cube root of the result. Thus, a jet injection of 0.2 cc that
occupies a sphere of
2.44 cc would have a diameter of 1.67 cm. Using this diameter as the minimum
allowable distance between each of the six exit nozzles, an analysis of the
three
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configurations shows that the rectangular option occupies the smallest surface
area at the
injection site. Based on these calculations, a six channel rectangular housing
has been
designed and fabricated as shown in Figures 1, 2, 3 and 4. The result of these
calculations is shown in Figures 10-12, wherein Figure 9 shows a rectangular
configuration, Figure 10 shows a pentagonal configuration, and Figure 11 shows
a
hexagonal configuration. Arrows 121 in Figure 10, 123 in Figure 11, and 125 in
Figure
12 are each 1.67 cm. An arrow 127 in Figure 11 is 1.96 cm. The results of the
foregoing
research is shown in the following table:
Orifice Configuration and Surface Area Needed to Prevent Overlap of Six 0 2 cc
Shots
Orifice Confi oration Surface Area (cm2)
Rectangle 5.58
Pentagon 6.63
Hexagon 7.24
The invention has been described in detail with particular emphasis on the
preferred embodiments thereof, but variations and modifications within the
spirit and
scope of the invention may occur to those skilled in the art to which the
invention
pertains.
