Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DENTAL CARTRIDGE A88EMHLY AUTO-INJECTOR
WITH PROTECTIVE NEEDLE COVER
Injection devices, such as automatic
injectors, are well known and are described, for
example, in U.S. Patents Nos. 5,102,393 and
5,085,641, of common assignment herewith:
Basically, an
automatic injector is a device for enabling an
individual to self-administer a dosage of a liquid
medicament. An advantage of automatic injectors is
that they contain a measured dosage of a liquid
medicament in a sealed Sterile condition capable of
storage in such condition for extensive periods of
non-use, during which period immediate injection of
the stored dosage may be accomplished at any time.
Another advantage of automatic injectors is that the
administration of the self-contained dosage of
liquid medicament is accomplished without the
necessity of the user initially seeing the
hypodermic needle through which the liquid
medicament is injected or of manually penetrating
such a visible needle into the user's own tissue.
Instead, an automatic injector includes a needle
normally stored and concealed within a rigid outer
housing. Also contained in the housing is a
cartridge assembly, which comprises a sealed
cartridge or container containing the dose of
medicament, with a movable plunger rearwardly
confining the medicament within the container. When
a releasable spring assembly carried by the housing
is released, the needle projects from a forward end
of the housing, and the plunger is forced through
the container to displace the medicament therefrom
through the needle and into the flesh of the user.
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In recently issued U.S. Patent No.
5,295,965, of common assignment herewith,
there is disclosed an
automatic injector with the added feature that,
after an injection operation, a protective rigid
needle cover is spring biased against the skin and
moves outwardly to cover the needle as it is
withdrawn from the flesh. One advantage of such an
arrangement is that the user does not see the needle
even after the injection operation. Another
advantage is that the protective cover prevents
accidental or unwanted contact with. the projecting
needle after the injection operation. It should be
appreciated that the needle-protective cover
arrangement adds a level of complexity to the
automatic injector, as it requires the automatic
injector to effectuate relative movement of needle
cover with respect to the main body. An even
further level of complexity is added where the
protective needle cover is initially retracted with
respect to the injector body and has the capability
of being locked in the extended position wherein it
covers the projecting needle. Nevertheless, this
type of injector has now sparked a significant
amount of commercial interest.
In virtually all automatic injectors, the
medicament container is made from a glass, metal, or
plastic material. There is normally a significant
expense associated with manufacturing such
containers, and as a result, the total cost of
manufacturing the injector is greater than ~~hat is
desirable. Therefore, in an attempt to reduce some
of the manufacturing costs, some injectors have
employed what is known as a "dental cartridge"
assembly, which incorporates a standard medicament
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dental cartridge or container that is manufactured
in bulk quantities for the medical industry. The
container employed in a dental cartridge assembly is
tubular, preferably made of glass, and has a
' 5 rearward portion with an inner diameter greater than
the inner diameter of its forward portion. The
rearward end of the container may be sealed by a
medicament compatible plug inserted into the
container. The forward end of the container is
typically sealed by a medicament compatible rubber
disk-shaped member that forms a circumferential seal
with the forward lip of the tubular container by
being clamped thereto by a retaining member. Dental
cartridges or containers are used in various
applications as shown, for example, by U.S. Patent
Nos. 3,413,974; 3,368,557; 3,678,931; 3,825,003;
4,445,895; 5,085,641; 5,226,895 and 5,226,896.
Since such dental cartridges are mass produced, they
are significantly less expensive than other types of
cartridges, and it is thus desirable to incorporate
them into automatic injectors. The incorporation of
a dental cartridge in a cartridge assembly for an
automatic injector is also advantageous in that it
can easily be filled with medicament by standard
automatic filling machines.
Those automatic injectors which utilize
dental cartridges may be considered somewhat more
difficult to engineer than those which employ
containers that are specifically engineered to be
3o used with the auto-injector. For example, in non-
dental cartridge type automatic injectors, it is
possible to assemble the hypodermic needle together
with the cartridge so that the rearward end of the
hypodermic needle is pre-mounted relative to the
forward seal of the cartridge so that fluid
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communication between the needle and the medicament
can be easily established during operation. For
example, see the V.S.Patent No. 5,295,965.
This is to be contrasted with
the dental cartridge type automatic injector,
wherein the rearward end of the hypodermic needle is
initially held spaced from the disk-shaped sealing
member at the forward end of the container, and
wherein relative movement between the hypodermic
1o needle and the sealing member must take place in
order for the rearward end of the needle to pierce
the sealing member and thereby establish fluid
communication between the hypodermic needle and the -
~medicament. For example, in the
~ U.S. Patent No. 5,085,641, it is
necessary for the forward sealing member~of the
dental cartridge assembly to be bulged forward by
medicament pressure to be pierced by the rearward
end of the needle.
In the automatic injector industry, there
has been a need for an automatic injector that can
provide the benefits of the protective needle cover
assembly, while also having the cost-effectiveness
- obtained by use of a dental cartridge assembly:
Heretofore, a device with such level of complexity
has never been realized. It is thus an object of
the present invention to satisfy the need expressed
above in a most cost-effective and reliable manner.
In accordance with this object, the present
invention provides an automatic injection device
pre-loaded with a charge of medicament for
. automatically self-administering the medicament upon
actuation thereof. The injection device includes
a generally tubular outer body, having a rearward
end and a forward end, and a medicament cartridge
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assembly carried within the outer body. The
cartridge assembly includes i) a glass container
having a rearward portion thereof with a
predetermined inner diameter and a forward portion
thereof with an inner diameter smaller than the
predetermined inner diameter, ii) a charge of
medicament disposed within the glass container,
iii) a plunger member rearwardly confining the
medicament within the glass container and being
to slidably movable forwardly within the glass
container, iv) a seal for sealing the forward
portion of the glass container having the smaller
inner diameter and for forwardly confining the
medicament within the glass container. A needle is
disposed forwardly of the cartridge assembly within
the outer body. The needle has a forward end and a
rearward end, with the rearward end being disposed
proximate the seal and being separated from the
medicament by the seal when the injection device is
, in a storage condition. The seal and the needle are
movable with respect to one another so that the
rearward end of the needle pierces the seal to
establish communication with said medicament during
an injection operation. The needle and said body
being movable with respect to one another so that
the needle projects outwardly from the forward end
of the body during the injection operation. A rigid
needle cover member is normally maintained in an
inoperative position wherein the forward end of the
needle is permitted to extend forwardly beyond the
needle cover member and is movable relative to the
body to a protective position wherein the needle
cover member extends forwardly beyond the forward
end of the needle. The needle cover is movable from
the inoperative position to the protective position
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as a result of the injection operation. A loc)ting
arrangement loc3cs the needle cover in the protective
position after the injection operation so as to
maintain the cover member extending forwardly beyond
the forward end of the needle. A releasable drive
assembly comprises a releasable spring and a collet
member. The releasable spring is releasable in
response to a predetermined actuating procedure to
drive the collet member forwardly within the outer
body and thereby enable i) the cartridge assembly to
move relative to the needle so that the rearward end
of the needle pierces the seal to establish
communication with the medicament, ii) the needle to
move with respect to the body so that the needle
projects outwardly from the forward end of the body,
and iii) the needle cover to move relative to the
body from the inoperative position to the protective
position so that the needle cover member extends
beyond the forward end of the needle.
BRIEF DESCRIPTION OF TFiE DRAWINGS
FIGURE 1 is a longitudinal sectional view
of a first embodiment in accordance with the
principles of the present invention;
FIGURE 2 is an enlarged longitudinal
sectional view of the forward portion of the
automatic injection device shown in FIGURE 1;
FIGURE 3 is a longitudinal sectional view
similar to FIGURE 2, but showing the automatic
injection device after it has been actuated;
FIGURE 4 is a longitudinal sectional view
similar to that of FIGURE 3, but showing the
injection device of the first embodiment in a needle
protective position, wherein the needle cover member
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is extended in protective relation over a projecting
needle;
~ FIGURE 5 is a longitudinal sectional view
of a second embodiment of the automatic injection
device is accordance with the principles of the
present invention;
FIGURE 6 is an exploded view of various
components utilized in effectuating operation of the
needle cover assembly in accordance with the second
embodiment of the present invention.
FIGURE 7 is a plan view of a retaining
spring utilized in the needle cover assembly in
accordance with the second embodiment of the present
invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now, more particularly to the
drawings; there is shown in Figure 1 an automatic
injector, generally indicated at 8, which embodies
the principles of the present invention. The
automatic injector has an outer housing or body,
generally indicated at lo, and a dental cartridge
assembly 11 contained within the body. The outer
body comprises a main elongated tubular housing
member 13, and a forwardly disposed elongated
tubular housing member 15.
The dental cartridge assembly 11 comprises
a dental cartridge or container 12, which is tubular
in form, and usually made of glass, although it can
also be made of plastic or metal. The tubular
container 12 is opened at its opposite ends, and is
. necked-down at its forward end. More particularly,
a major portion 14 of the container 12 extends
rearwardly of the forward pecked down forward
portion 16 and has a predetermined inner diameter
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which is larger than the inner diameter of the
necked down forward portion. These portions can be
more clearly discerned in FIG. 2. The container has
an inwardly extending peripheral shoulder 18, which
integrally connects the main rearward portion of the "
container with the smaller diameter forward portion
of the container. The forwardmost end (generally
indicated at 24) of the container has a radially
outwardly extending flange 2o which receives a seal
member 22 to close off the forward end. The seal
member 22 is peripherally secured to the annular
forwardmost surface or lip of flange 20 at the
forward end of the container 12 by means of an
annular metallic clamping ring 26. A plunger 28
closes the open rearward end of the container 12 and
is mounted therein for forward sliding movement in
sealing relation with the interior surface thereof.
Preferably, the plunger 28 is a °'nipple-type'°
plunger for substantially expelling all medicament
. from the container 12. In another preferred
arrangement, the plunger 28 may be somewhat stunted,
and a "top-hat'° configuration can be used for the
seal member in order to substantially expel all
medicament from container 12. The aforementioned
arrangements for the nipple and/or seal member are
disclosed in the parent Patent 'Application Serial
No. 08/280,884, which is hereby incorporated by
reference. It should be appreciated, however, that
the aforementioned plunger and/or arrangements are
merely preferred and that the present invention
contemplates that any known type of plunger or
sealing arrangement can be used.
A slidable needle hub assembly, generally
indicated at 30, has a cup-shaped rearward portion
31 opened towards the rear of the body lo. The
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forward end of the container 12, including clamp
ring 26, extends partially into the rearward portion
31 in telescopic relation. An exterior periphery of
the forward end of cartridge assembly 11, i.e., the
radially outermost surface of clamp ring 26,
frictionally engages the rearward portion of the
cylindrical inner surface of the rearward portion
31. The needle hub assembly 30 has a substantially
narrowed diameter forward portion 32 thereof
to disposed in surrounding relation to a hypodermic
needle 34. The needle 34 is secured at a central
peripheral portion 33 thereof to the hub assembly
30.
' The forward portion of the needle 34 may
be covered by a protective sheath 44 to maintain the
sterility of the needle and to act as a shock
absorber for the cartridge assembly 11 as the
cartridge assembly is moved forwardly towards the
front end of the body during an injection procedure.
A similar sheath is disclosed in U.S. Patent No.
3,882,863.
A tubular protective needle cover member
40 is disposed in surrounding relation to the
forward portion of the needle. The needle cover
-. 25 member is substantially tubular, and has a rearward
portion of slightly greater inner diameter so as to
present a rearwardly facing annular surface 41. A
coil spring 42 has its forward volute resting upon
annular surface 41 and its rearward volute resting
upon a forwardly facing annular surface 43 of the
rearward cup-shaped portion 31 of needle hub
. assembly 30 so as to be slightly compressed
therebetween before an injection operation.
The cover member is spring biased by the coil spring
42 to move forwardly in protective relation over the
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needle after an injection operation wherein the
needle projects from the forward end of the device.
The needle cover member will be described in greater
detail, infra.
A releasable drive assembly 50 is provided
within the rearward portion of the main housing
member 13. The drive assembly 50 includes a coil
spring 62, and a collet member generally indicated
at 66. The main housing member 13 is formed with an
l0 interior annular flange 60 spaced slightly inwardly
from the rearward end thereof. The forward surface
of the annular flange 60 is adapted to be engaged by
a rearward volute of the coil spring 62, which
operates as a releasable energy source for the
injector of the present invention. It is understood
that the present invention is not limited to the use
of a coil spring and that any releasable energy
source, such as an air spring, or chemical expansion
reaction, may be used. The forward volute of the
coil spring 62 engages a rearwardly facing surface
of a forward flange 64 of the collet member 66.
The collet member 66 extends rearwardly
from the forward flange 64 thereof within the coil
spring 62. The rearward end portion of the collet
member 66 is split so as to form a plurality (two)
of rearwardly extending spring fingers 68. The
rearward peripheral portion of the fingers 68 are
formed with radially outwardly extending flanges
presenting forwarding facing locking surfaces 74
which are adapted to engage along a generally
radially extending plane with the rearwardly facing
surface of the interior annular flange 60 of the
housing member 13.
As shown in FIG. l, a safety actuating pin
member, generally indicated at 76, is disposed in
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cooperating relation with the resilient fingers 68
in a storage position and includes a forward portion
78 which extends inwardly between the resilient
fingers 68. The safety actuating member 76 also
includes an intermediate portion 80 of a reduced
diameter with respect to the forward portion 78,
there being a frustoconical transition 81 between
the two portions. The larger forward portion 78
extending between fingers 68 is cylindrical in form
1o and, in the position shown in FIG. 1, engages the
rearward generally arcuate inner facing surfaces 79
of the spring fingers 68 so as to prevent the
fingers from moving radially inwardly toward one
another, thereby maintaining the locking surfaces 74
of the spring fingers 68 in engagement with the
rearwardly facing locking surfaces of flange 60.
Thus, coil spring 62 is retained in a stressed
condition between the forward flange 64 of the
collet member 66 and the forwardly facing surface of
the interior flange 60 of housing member 13. As
shown in FIGURE 1, immediately forwardly of the
rearward arcuate inner facing surfaces 79, the
spring fingers 68 have arcuate inner surfaces 83 of
a greater diameter than surfaces 79 so as to define
a relatively large diameter space 86 in comparison
to the space defined by surfaces 79. As also shown
in FIGURE 1, a cap structure 88 is in a storage
position, and covers actuating member 76.
The rearward end of the tubular housing
member 15 is telescopingly received over the forward
portion of the main tubular housing member 13. More
- particularly, the housing member 13 has an annular
flange 92 radially extending outwardly from an
exterior surface thereof. The housing member 15 has
an annular groove 94 formed in the interior surface
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thereof toward the rearward portion thereof. The
forward housing member 15 is secured to the main
housing member 13 by rearwardly sliding the rearward
end of the housing member in telescoping relation
over the forward end of the housing member 13 until '
the annular flange 92 of the housing member 13 snaps
into the annular groove 94 of the housing member 15.
The forwardmost portion of the housing member 15 has
a radially inwardly extending flange 98. The flange
98 has a generally inwardly bulging axially
extending interior surface 100, and a generally flat
annular rearwardly facing surface 102, as shown.
The forward end of the tubular protective
needle cover member 40 has a radially inwardly
extending flange 104, having a central aperture 106.
The forward end of the tubular needle cover also has
a small annular ridge 108 radially extending
outwardly from the forwardmost portion of the
cylindrical exterior surface thereof. When the
automatic injector is in its storage condition,
i.e., prior to use, the needle cover is retained
within the forward housing member 15 by virtue of a
frictional, interference fit between the ridge 108
and the inwardly bulging interior surface 100 of
flange 98. In an alternative configuration, the
surface 100 of flange 98 may be provided with a
slight annular notch adapted to receive the annular
ridge 108 of the needle cover 40 to retain the
needle cover within the forwardly disposed housing
member 15 against the bias of spring 42 prior to an
injection operation.
A somewhat tubular leaf spring element 110
is disposed within the housing member 15 between the
rearwardly facing surface 102 flange 98 and the
forwardmost end of the main housing member 13. More
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specifically, the spring element is cylindrical,
except for the provision of a radially inwardly
extending arcuate projection 112 disposed at the
rearwardmost end thereof, and a spring tab member
114 cut into the forward portion of the spring
element. The spring tab member 114 is elongated,
flexible, and integrally connected at its rearward
end with the spring element 110 generally at a
longitudinal midpoint of the spring element. The
l0 tab member 114 extends forwardly and inwardly from
its rearward end toward its forward end and has its
forward end disposed in resilient, spring biased
engagement with an exterior cylindrical surface 116
of the needle cover 40.
The needle cover 40 has an annular flange
118 extending radially outwardly from the exterior
surface 116 thereof and disposed slightly spaced
from the rearward end thereof. The flange 118 has a
rearwardly facing annular surface 120, which engages
a forwardly facing surface 122 of the inwardly
extending projection 112 when the needle cover is
disposed within the forward housing member 15 in its
inoperative position as shown in FIGS. 1 and 2.
This engagement prevents the needle cover 40 from
being pushed back into the body 12 to a greater
extent than what is desirable. When the needle
cover 40 is deployed during an injection operation,
the spring tab member 114 is caused to ride over and
snap behind the flange 118. The forward end of the
spring tab member 114 then rests behind or upon
surface 120 of the flange 118 and thereby prevents
rearward movement of the needle cover 40. Thus, the
spring member 114 and flange 118 operate as a
locking arrangement for locking the needle cover 40
in its protective position after an injection operation.
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To effectuate an injection, the cap
structure 88 is removed, and the user grasps body to
in one hand and places the forward end of the
injector against the portion of flesh to be
injected. Next, the safety actuating pin member 76
is moved forwardly by a thumb or other finger so
that the forward larger portion 78 of the actuating
member 76 is moved into the larger space 86 defined
by inner arcuate surfaces 83 of spring fingers 68.
to During such movement, the narrowed diameter
intermediate portion is also moved into the fingers
and permits the rearward portion of the fingers to
flex inwardly to an extent sufficient such that the
locking surfaces 74 are moved off of the flange 60,
allowing the collet member 66 to move forwardly
under the action of the spring 62. The collet 66
continues to move forwardly, while the safety
actuating pin member 76 is left behind in captured
relation by the rearward flange 60 of housing member
13.
The collet member 66 during its forward
movement is forced against the rearward surface of
plunger 28. This in turn causes the entire
cartridge assembly 11 to move forwardly within the
body 10 so that the forward end of the needle 34
projects from the forward end of the injector while
compressing sheath 44 and spring 42. This is
clearly shown in FIGURE 3. Further movement of the
cartridge assembly 11, as also shown in FIGURE 3,
3o causes the forwardly facing surface 43 of hub
assembly 30 to engage the rearwardmost end of needle
cover member 40 so as to move the needle cover
member 40 forwardly so that the ridge 108 thereof is
forced out of interference engagement with the
radially inwardly bulging surface 100 of housing
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member 15. This slight movement of the needle cover
member 40 will enable the cover member to be moved
fully outwardly into protective relation over the
needle 34 when the needle is withdrawn from the
flesh. As can also be appreciated from FIGURE 3,
the forwardly facing surface 43 of the hub assembly
30 eventually engages the rearward facing surface of
projection 112, which halts any further movement of
the hub assembly 30. Continued force provided and
momentum by the coil spring 62, however, causes the
forward portion of the exterior periphery of
cartridge assembly 11, i.e., the radially outermost
surface of clamp ring 26, to slide forwardly in
frictional engagement with the rearward portion of
the cylindrical inner surface of the portion 31 of
hub assembly 30. As a result, the rearward end of
the needle 34 pierces the seal member 22 to
establish communication with the medicament 36
through the seal.
After the forwardmost portion of the
cartridge assembly extends as far as possible into
the rearward portion 31 of the hub assembly 30 so as
to engage the rearwardly facing annular surface 121
thereof, the continued spring-biased force of the
collet member 66 acts to move the plunger 28
forwardly through the container 12. This movement
of the plunger 28 pressurizes the liquid medicament
36 and begins to force it through the needle 34.
As shown in FIGURE 4, which shows the
automatic injector after the needle is withdraw from
the flesh of an individual, the needle cover member
is permitted to move forwardly with respect to
the body 10 from its inoperative position (as shown
,a in FIGURES 2 and 3) to a protective position wherein
35 it extends beyond the forward end of the needle 34
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with the needle projecting outwardly from the
forward end of the body. The needle cover member 40
will continue to move forward until the forward
facing surface of flange 118 engages the rearwardly
facing surface 102 of housing member 15. When the
needle cover reaches its forwardmost position, the
spring tab member 114 rides over and snaps behind
flange 118 to lock the needle cover is its
protective position covering the needle 34. In
addition, when the needle cover moves to its
protective position, the resilient sheath 44 is
permitted to relax and move outwardly to cover the
needle 34 within the cover 40 to further insulate
the now blood contaminated needle.
FIGURE 5 shows another embodiment in
accordance with the principles of the present
invention. The embodiment shown in FIGURE 5 is
substantially identical to the embodiment shown in
FIGURE 1, with the exception of the differences
about to be described. Common elements between the
two embodiments are designated by the same reference
numerals.
Beginning with the rearward portion of the
injection device, it can be appreciated that the
outer housing or body 200 is formed from two
separate housing members, including a forward
housing member 202 and a rearward housing member
204. The rearward interior surface of the forward
housing 202 is provided with an annular groove 206.
The rearward housing member 204 has an annular
flange 208 extending radially outwardly from the
exterior surface thereof and is slightly spaced from
the forwardmost end of the housing member 204. The
flange 208 is received within the groove 206 to
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thereby secure the rearward housing member 204 to
the forward housing member 202.
' A safety cap member 210 is provided and is
also formed from two separate structures, including
- 5 a tubular forward structure 212 and a rearward plug
214 that is inserted into the rearward end of the
tubular structure 212. The plug 214 has a circular
end portion 216 and a cylindrical wall portion 218
extending forwardly therefrom into the interior
l0 confines of the tubular structure 212. The
cylindrical wall portion 218 has an exterior annular
flange 220, which is received in an internal annular
groove 222 provided in the rearward portion of the
forward tubular structure 212 so as to secure the
15 plug 214 to the forward structure 212. The
cylindrical wall 218 has an inwardly extending
annular flange 226 at the forward end thereof. An
annular groove 228 is disposed within the exterior
surface of the rearward housing member 204. The
20 . flange 226 of the plug member 214 is received within
the groove 228 to enable the cap member 21o to be
removably secured to the rearward housing member
204. The cap member 210 can be removed from the
rearward housing member 204 by grasping the exterior
25 surface of the forward housing member 202 with the
palm and fingers of one hand and pulling the cap
member 210 rearwardly with the other hand so that
the annular flange 226 rides out of the annular
groove 228. Further features and advantages of the
30 interrelation between the cap member 210 and the
rearward housing member 204 can be appreciated from
U.S. Patent No. 5,085,641, which is hereby
incorporated by reference. For example, preferably,
the cap structure 210 is constructed and arranged
35 such that its clip must be rotatably aligned with an
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indicia on the rearward housing member before it can
be removed, as disclosed in the aforementioned
patent. Removal of the cap member 210 permits
manual access to the safety pin 76 as with the first
embodiment.
At the forward end of the forward housing
member 202 is an annular interior groove 230. A
forward end cap assembly, generally indicated at
232, is secured to the forward end of the tubular
housing member 202. More specifically, as will be
described in conjunction with FIGURES 5-7, the end
cap assembly 232 comprises a tubular needle housing
member 234, a tubular end cap member 236 secured to
the needle housing member 234, a generally tubular
needle cover member 238 disposed within the needle
housing member 234, and a substantially triangular
(see FIGURE 7), radially outwardly biased retaining
spring 240 for locking the needle cover member 238
in the extended, protective position. The needle
housing member 234 has a forwardly disposed exterior
annular flange 242, which is received within the
internal annular groove 230 of the forward housing
member 202, so as to secure the end cap assembly 232
to the forward housing member 202. The needle
housing member 234 also includes a centrally
disposed exterior annular flange 243 of a greater
diameter than flange 242. The flange 243 engages
the forward annular surface of the housing member
202 to prevent the housing member from extending
therebeyond. Forwardly spaced from flange 243 is a
third flange 244 radially extending from the
exterior surface of housing member 234. The flange
244 is received within an annular groove 246
disposed within the interior surface of the end cap
member 236 so as to secure the needle housing member
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234 to the end cap member 236. The forward portion
of the needle housing member 234 has an annular
groove 252 forming part of the interior surface
thereof. The groove 252 has a rearward and radially
- 5 outwardly extending surface 254, forming somewhat of
a "V"-shaped notch, as shown.
The needle cover member 238 has a pair of
longitudinally spaced annular flanges 248 extending
radially outwardly from an exterior surface thereof.
The flanges 248 define a groove 250 therebetween,
within which; retaining spring 240 is retained. Upon
activation of the injection device of the second
embodiment, the needle cover member 238 is moved
outwardly to the protective position in
substantially the same manner described with respect
to the first embodiment.
The retaining spring 24o is biased for
radially outward expansion against the interior
cylindrical surface 235 of the needle housing member
234. During movement of the needle cover member 238
forwardly under the force of a conical coil spring
260 into the protective position, the retaining
spring 240 is moved in sliding engagement with the
interior cylindrical surface 235 of the needle
housing member 234. When the retaining spring 240
reaches the groove 252, it is able to expand
radially outwardly into said groove.
The expansion of the retaining spring 240
into the groove 252 provides for an interference
between the needle cover member 238 and the needle
housing member 234 so as to lock the needle cover
member 238 in the forwardly extending, protective
position. More particularly, any attempt to move
the needle cover member 238 back into the injector
housing will be prevented, as the surface 254 of the
19
CA 02234996 1998-04-16
WO 97/14455 PCT/US96/15786
groove 252 formed in needle housing member 234 will
engage spaced portions of the rearwardly facing
surface of the retaining spring 240, which spring '
continues to be retained between flanges 242 of
cover member 238. As a result, the needle cover
member 238 is prevented from moving rearwardly into
the auto-injector.
It thus will be seen that the objects of
this invention have been fully and effectively
l0 accomplished. It will be realized, however, that
the foregoing preferred specific embodiment has been
shown and described for the purpose of this
invention and it is subject to change without
departure from such principles. Therefore, this
invention includes all modifications encompassed
within the spirit and scope of the following claims.
