U.S. patent number 3,882,863 [Application Number 05/384,682] was granted by the patent office on 1975-05-13 for hypodermic injection device having cannula covered with resilient sheath.
This patent grant is currently assigned to Survival Technology, Inc.. Invention is credited to George B. Calkins, Stanley J. Sarnoff.
United States Patent |
3,882,863 |
Sarnoff , et al. |
* May 13, 1975 |
Hypodermic injection device having cannula covered with resilient
sheath
Abstract
A hypodermic injection device comprising a cartridge holder
having a cylindrical body open at one end and closed at the other
end, the closed end being provided with an aperture, a cartridge
including an ampoule with attached cannula within the holder, the
cannula being directed toward the holder's closed end, the ampoule
including a cylindrical sleeve slidably carrying a piston, the
sleeve being open at one end and having a necked portion at the
other end to receive a hub mounting the cannula, fluid medicament
in the sleeve between the piston and cannula, a spring power
assembly for moving the cartridge forward and for injecting the
fluid medicament carried in the ampoule, a safety assembly for
controlling actuation of the spring power assembly, and a resilient
sheath covering the cannula to maintain the cannula in sterile
condition.
Inventors: |
Sarnoff; Stanley J. (Bethesda,
MD), Calkins; George B. (Bethesda, MD) |
Assignee: |
Survival Technology, Inc.
(Bethesda, MD)
|
[*] Notice: |
The portion of the term of this patent
subsequent to March 19, 1991 has been disclaimed. |
Family
ID: |
23518311 |
Appl.
No.: |
05/384,682 |
Filed: |
August 1, 1973 |
Current U.S.
Class: |
604/136 |
Current CPC
Class: |
A61M
5/32 (20130101); A61M 5/2033 (20130101); A61M
2005/206 (20130101); A61M 2005/2073 (20130101) |
Current International
Class: |
A61M
5/20 (20060101); A61M 5/32 (20060101); A61m
005/20 () |
Field of
Search: |
;128/218F,218D,218DA,218A,218NV,218M,218R,272,215,218N,221 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: McGowan; J. C.
Attorney, Agent or Firm: Witherspoon and Lane
Claims
What is claimed is:
1. In a hypodermic injection device comprising a gun, a cartridge
holder in operative relationship to the gun, a cartridge within the
holder, said gun comprising a sleeve open at one end thereof, a
plunger positioned within the sleeve, spring power means acting on
said plunger tending to move it out the open end of the sleeve,
restraining means cooperating with said plunger to prevent plunger
movement, safety means acting on said restraining means to render
it inoperative, said cartridge holder comprising a hollow shell
acting as a prolongation of the gun sleeve, said cartridge
including an ampoule comprising a hollow cylindrical sleeve, a
piston slidably positioned in one end thereof and means mounting a
cannula extending from and closing off the other end, a fluid
within the cylindrical sleeve between the piston and the cannula,
the cartridge fitting within the cartridge holder with the free end
of the cannula within the end of the holder remote from the gun,
the improvement comprising:
a resilient sheath covering the cannula, said sheath having a
closed end and an open end, the length of the sheath being sized
such that when assembled on the cannula the closed end of the
sheath is not pierced by the cannula end, and means for preventing
forward movement of the closed end of the sheath whereby when the
power means forces the cartridge forward the cannula will pierce
the closed end of the sheath and deliver the fluid medicament from
the ampoule sleeve.
2. The invention as set forth in claim 1 and wherein the resilient
sheath comprises a resilient cylinder having a closed and an open
end, the length of the sheath being sized such that the closed end
thereof is spaced from the cannula end.
3. The invention as set forth in claim 1 and wherein the resilient
sheath is so sized that upon forward movement of the cartridge, the
sheath will be compressed between the cannula hub and the forward
end of the cartridge holder and act as a shock absorber.
4. The invention as set forth in claim 3 and wherein the size of
the resilient sheath is such that it is never fully compressed,
even when the cartridge is fully extended.
5. The invention as set forth in claim 4 and wherein means are
provided in the forward end of the cartridge holder for centrally
positioning the closed end of the resilient sheath in the cartridge
holder.
6. The invention as set forth in claim 1 and wherein the resilient
sheath is so sized that when it is compressed by the full extension
of the cartridge under action of the power means the reactionary
energy stored in the compressed sheath will overcome the force of
the power means and retract the cannula a small distance.
7. The invention as set forth in claim 3 and wherein the
cylindrical sleeve is made of glass.
Description
SUMMARY OF THE INVENTION
This invention relates to injection devices of the gun type wherein
spring power means drives an ampoule and cannula to insert the
cannula and then inject the medicament. The cannula is provided
with a resilient sheath to maintain the cannula in sterile
condition at all times prior to injection.
In the device of this invention, the ampoule and attached cannula
are slidably carried in a cylindrical holder which is closed at the
end housing the cannula except for an aperture through which the
cannula passes when the unit is actuated. A spring power assembly
drives a plunger which engages the ampoule to drive the ampoule and
cannula forward causing the cannula to travel out through the
aperture in the closed end of the cylindrical holder and to enter
the locus which is to receive the fluid medicament. Continued
movement of the plunger, after placing of the cannula in the locus,
forces a piston in the ampoule forwardly to inject the medicament.
During this action, the resilient sheath positioned on and over the
cannula is held within the closed end of the cylindrical holder and
is pierced by the end of the cannula as it proceeds forwardly. As
the cannula continues forward, the sheath is compressed between the
closed end of the cylindrical holder and the cannula hub. This
action continues until the cannula is fully extended, at which time
the sheath is not quite fully compressed, thus making it possible
for the sheath to act as a shock absorber at all times during
forward travel of the cannula. Toward the end of injection, the
forward travel of the power spring is such that its energy is less
than that now stored in the compressed sheath. Therefore, a slight
retraction of the cannula occurs during the terminal portion of the
injection.
In view of the foregoing, it is an object of this invention to
provide a gun type injection device with a resilient cannula sheath
for maintaining the cannula in sterile condition at all times prior
to actuation.
It is another object of this invention to provide a gun type
injection device with a resilient cannula sheath to act as a shock
absorber during operation of the device.
It is a further object of this invention to provide a gun type
injection device wherein the cannula is covered by a resilient
sheath which upon being compressed when the device is actuated will
react to retract the cannula a small distance during the terminal
portion of injection.
IN THE DRAWINGS
FIG. 1 is a longitudinal broken away view, partly in section,
illustrating the sheath as applied to the cannula when the
injection device is in ready position;
FIG. 2 is a view similar to FIG. 1, showing the compressed sheath
after firing of the injection device with the cartridge fully
projected and just prior to the forward movement of the plunger and
injection of the medicament; and
FIG. 3 is a view similar to FIG. 2, illustrating a slight
retraction of the cannula from the fully extended position of FIG.
2 which retraction occurs during the terminal portion of the
injection.
DETAILED DESCRIPTION OF THE INVENTION
The single embodiment of this invention illustrated in FIGS. 1-3 is
merely one example of the injection apparatus that can
advantageously use the cannula sheath arrangement of this
invention.
The device comprises an outer cylindrical sleeve 100 having an
inturned shoulder 110 at one end and an annular groove 113 in the
inner wall adjacent the other open end. A cartridge assembly 106 is
assembled in the shouldered end of the outer sleeve 100. The
cartridge assembly 106 includes a cartridge holder sleeve 104
fitted within the sleeve 100 and having a decreased forward end
portion 153 forming a shoulder 154 which fits against seat 112
provided by outer sleeve shoulder 110. The extreme forward end
portion 156 of the holder sleeve 104 is tapered to form a small
circular aperture.
The cartridge 135 includes an ampoule cylinder 136 with liquid
medicament 146 there within and a piston 148 at one end with a
cannula 150 at the other end. The ampoule cylinder 136 has a necked
portion 80 with a diameter less than that of the cylinder 136 and
terminates in an enlarged annular flange. The cannula 150 is
secured to a cannula hub 81 which in turn is affixed to the
enlarged flange on the necked portion 80. More specifically,
cannula hub 81 comprises a reduced diameter portion 84 which is
secured to cannula 150 and an intermediate body 86 connected to
enlarged body 88. The enlarged body 88 fits over and is secured to
the annular flange of the necked portion 80 of the ampoule
cylinder. Within the neck of the ampoule cylinder 136, between the
inner end of the cannula 150 and the medicament, there may be
interposed a fluid pressure rupturable diaphragm generally like
that described in U.S. Pat. No. 3,391,695 to Sarnoff.
The cartridge assembly 106 is assembled in the outer sleeve 100
with the cannula 150 spaced from the apertured end of the holder
104. The overall length of the ampoule 135 and cannula 150 is such
that it is all contained within the holder sleeve 104, as
illustrated in FIG. 1.
The outer sleeve 100 is of such length that it accommodates the
cartridge assembly 106 in one end and receives the gun assembly 200
in the other to complete the device. The gun assembly 200 comprises
an inner gun sleeve 101 having an out turned flange 103 which fits
up against the end of the cartridge holder sleeve 104 when the gun
assembly is inserted in the outer sleeve 100. The other end of the
inner gun sleeve 101 is centrally apertured to form a hole 120. The
rear outer face 122 of the inner gun sleeve 101 is planar and
perpendicular to the longitudinal axis of the sleeve for a purpose
to be brought out later.
A plunger 162 fits within the out turned flange end of the inner
gun sleeve 101. This plunger has a cylindrical body portion 163 and
a circular head portion 164 of a diameter larger than the body
portion 163 and generally slightly less than that of the piston 148
in the ampoule 135. The head 164 has an opening which is sized to
align and correspond to the through hole 166 in the plunger body
163. The plunger head 164 is provided with a plurality of
circumferentially spaced, radially extending tabs 168. These tabs
168 form a diameter greater than that of the plunger head 164 so
that the tabs will engage the end of the ampoule cylinder 136.
Longitudinal slots 172 are formed in the plunger head 164
immediately behind the tabs 168. These slots are sized so that they
will accommodate the tabs 168 when they are later broken off or
bent rearwardly in the operation of the device. These slots extend
throughout the length of the head behind the tabs.
Referring to FIGS. 1 and 2, a locking detent 176 is fitted through
the hole 166 in the plunger 162 and has a central body portion 178
with outwardly extending lugs 180 on one end fitting an annular
shoulder 182 of the plunger head 164. The other end of the locking
detent 176 is provided with four equally spaced, longitudinally
extending springy detent arms terminating in frusto-conical detent
heads 186. This locking detent 176 maintains the plunger 162 and
inner gun sleeve 101 in assembled position with a coil spring 138
compressed therebetween as follows: A coil spring 138 is positioned
over the plunger body 163 and abuts the plunger head 164 at one end
and the inner face of the end wall of the inner sleeve 101 at the
other. Upon compressing of the coil spring 138 sufficiently, the
detent heads 186 will be cammed inwardly by engaging the periphery
of the end wall opening 120 and pass therethrough whereupon the
bases of the detent heads 186 will come to rest on the planar face
122 of the inner gun sleeve 101 to retain the plunger and inner gun
sleeve in assembled condition with the coil spring 138 compressed
therebetween. When desired, the rear planar surface 122 of the
inner sleeve 101 may be overlaid with a metal washer 127, in which
case it is advantageous to provide a guide and holding flange 128
to surround the opening 120. The flange 128 is provided with a lip
portion to retain the washer in place.
As illustrated in FIGS. 1 and 2, the inner gun sleeve 101 has a
plurality of longitudinally extending raised ribs 129 running from
the flange 103 approximately one-half the length of the said
sleeve. An outer gun sleeve 192 fits over inner gun sleeve 101 and
is sized to frictionally engage ribs 129. The outer sleeve 192 has
a closed end 194 with a central aperture 196 from which extends a
frusto-conical cam surface 198 sized and shaped to cooperate with
frusto-conical detent heads 186 to cam said heads radially
inwardly. The outer gun sleeve 192 is provided with a
circumferential locking rib 199 which fits in groove 113 in the
outer sleeve 102 to retain the gun assembly 200 in position in said
outer sleeve. It should be noted that the length of outer gun
sleeve 192 is slightly less than that of the inner gun sleeve 101
so as to make certain that there will be space between the inner
wall of the outer gun sleeve 192 and the flange 103 of the inner
gun sleeve 101 so that the two gun sleeves may move relative to
each other to cam frusto-conical detent heads 186 inwardly in
operating the device.
In order to make certain that the frusto-conical detent heads 186
are not accidentally cammed inwardly, a safety pin assembly is
provided. This safety pin assembly comprises a cap 142 having a
cylindrical sleeve 143 sized to fit over the end portion of outer
gun sleeve 192. A safety pin 144 extends inwardly from the center
of the cap 142 into the opening formed by the inner portions of the
detent heads 186 to thereby prevent inward movement of said detent
heads. The cap 142 is provided internally with a plurality of
spacer abutments 145 to assure proper positioning of the cap on the
outer sleeve 192.
As shown in FIG. 1, resilient sheath 250 is positioned over the
cannula 150 such that the open end of the sheath fits over and
around cannula hub portion 84 and abuts the shoulder 82 formed by
hub portions 84 and 86. The length of the sheath is such that its
closed end is slightly beyond or spaced from the end of cannula
150. In order to make certain that the sheathed cannula is
maintained in proper alignment with aperture 158, a plurality of
ribs 157 is formed on the inner face of tapered holder portion 156
surrounding said aperture. Thus, the end of the sheath 250 is held
in necessary alignment by bearing against the converging section of
the ribs 157.
Upon the actuation of the injection device, the cartridge assembly
106 moves forward whereby the sheath 250 is compressed between the
cannula end of the cartridge holder sleeve 104 and the hub shoulder
82, as illustrated in FIG. 2. The cannula sheath, in being
compressed, acts as a shock absorber to gradually absorb some of
the energy provided by the power spring 138 as it drives the
cartridge assembly 106 forward. It should be noted that at no time,
even when the cannula is fully extended, is the sheath compressed
to such an extent that it would act as a solid and thereby provide
no shock absorbing in such a condition.
When the cannula 150 is fully extended as shown in FIG. 2, the
cannula sheath 250 will be compressed the greatest amount hence the
largest reactionary force will exist in the compressed sheath in
such position. As illustrated in FIG. 2, the cartridge 135 has
completed its travel under the force of spring 138 and the forward
movement of piston 148 commences under the action of spring 138 to
start the injection cycle. The size of the sheath is such that in
the maximum compressed condition, as in FIG. 2, the forces stored
in the sheath are greater than those in spring 138 when it has
reached a point just short of full piston travel. At this point the
compressed sheath 250 takes over and causes the cartridge 135 and
attached cannula 150 to retract slightly, as shown in FIG. 3, while
the last stage of injection takes place. It is at this stage that
the forces of the compressed sheath and the spring 138 are
counterbalanced.
The importance of the sheath 250 and its multiple features is even
more important when consideration is taken of the fact that most of
the ampoule cylinders (i.e. cylinder 136 of the device illustrated)
are made of glass and hence are subject to breakage under certain
amounts and types of shock. The shock absorbing feature enjoyed by
the use of the cannula sheath of this invention contributes
substantially to overall quality and reliability. Furthermore, the
covering of the cannula with the sheath provides greater ease in
assembly since it is not necessary to maintain any of the inner
portions of the holder and associated elements in sterile
condition.
The type of material from which the sheath 250 can be made varies
substantially. Even so, the preferred material would be one having
good resilient characteristics such as various types of rubber and
synthetics. Shelf life is also important. By this it is meant that
the material should retain its characteristics over a substantial
period of time and under varied conditions.
* * * * *