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Claims  |
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We claim:
1. A hypodermic syringe system, comprising:
(a) a syringe barrel;
(b) a syringe plunger including a frangible end sealing an interior cavity,
said syringe plunger sized to be received within and slide through said
syringe barrel;
(c) an injection needle; and
(d) a spring holding means associated with and held by said syringe barrel,
for holding said injection needle and selectively retracting said
injection needle into said interior cavity of said syringe plunger when
said syringe plunger abuts against and moves beyond a portion of said
syringe barrel, causing breakage of said frangible end, and allowing said
frangible end of said syringe plunger to separate, wherein said spring
holding means, comprising: a holder for holding said injection needle; and
a spring means for exerting an expansive force between said holder and
said spring holding means, wherein said spring holding means selectively
holds said holder and said spring means therebetween while allowing said
injection needle to extend through said spring holding means in an
assembled condition wherein said holder has a lip, said spring holding
means has extending resilient fingers with interior and inferiorly
positioned hooks to retain said lip of said holder in an assembled
condition wherein, said frangible end of said syringe plunger has an
engaging and complementing surface which abuts up against said hooks of
said extending resilient fingers, spreading said extending resilient
fingers radially outwardly to release said lip against the expansive force
of said spring means when said syringe plunger moves beyond said portion
of said syringe barrel.
2. A hypodermic syringe system as claimed in claim 1, wherein said
frangible end of said syringe plunger separates when a predetermined
normal force is exerted between said frangible end of said syringe plunger
and said holder.
3. A hypodermic syringe system, as claimed in claim 2, wherein said
frangible end of said syringe plunger spreads said extending resilient
fingers radially outward upon depression of said syringe plunger past said
predetermined point within said syringe barrel prior to exertion of said
predetermined normal force, allowing said frangible end to dissociate and
said spring means to propel said holder and injection needle into said
interior cavity of said syringe plunger.
4. A hypodermic syringe system, as claimed in claim 3, wherein said spring
holding means operatively dissociates from a nose section of said syringe
barrel.
5. A hypodermic syringe system as claimed in claim 4, wherein said interior
cavity of said syringe plunger is evacuated prior to the separation of
said frangible end from said syringe plunger.
6. A hypodermic syringe system as claimed in claim 5, further comprising
ratchet means for engaging said syringe plunger with said syringe barrel,
preventing separation of said syringe plunger from said syringe barrel
after said syringer plunger is depressed within said syringe barrel.
7. A hypodermic syringe system as claimed in claim 6, wherein said spring
holding means includes at least one extending tab and wherein said nose
section of said syringe barrel includes at least one interior axial slot
and an adjoining inner radial slot, both sized to receive said tab and
allow secure engagement between said spring holding means when associated
with said nose section by positioning said tab through said axial slot and
rotating said tab within said radial slot, thereby securing said spring
holding means to said nose section.
8. A hypodermic syringe as claimed in claim 7, wherein said spring holding
means has a frustoconical head, an axial bore through said head, of a
sufficient diameter to receive said injection needle therethrough, and a
cylindrical exterior groove sized to receive and retain an O-ring of
sufficient size to engage tapered interior walls of said nose section of
said syringe barrel and provide sealing engagement between said spring
holding means and said nose section.
9. A syringe system as claimed in claim 8, wherein said holder is a highly
visible color and wherein said syringe plunger and said syringe are made
of a translucent or transparent material, to allow viewing said holder
when ejected into said syringe through said syringe barrel.
10. A syringe system as claimed in claim 9, wherein said head of said
spring holding means includes an engagement groove for engagement with a
needle cap.
11. A syringe system as claimed in claim 10, comprising a color-coded ring
of sufficient diameter to slide over an exterior surface of said syringe
barrel and be retained thereby to identify the syringe system.
12. A hypodermic syringe, comprising a spring-loaded needle means for
holding and ejecting a captured needle, barrel means for holding
injectable fluid therein and connectable to said spring-loaded needle
means on one end, and a hollow plunger means positionable within and
movable through said barrel means, said plunger means having a breakable
end which breaks free from one end of said hollow plunger means and allows
said captured needle to be ejected into said hollow plunger means within
said barrel means, wherein said spring loaded needle means having a
housing with resilient fingers on one end, which can be spread radially
outwardly by said one end of said hollow plunger means in contact
therewith to release said captured needle from said housing, wherein said
breakable end of said hollow plunger means breaks allowing said captured
needle to be propelled out of said housing and into said hollow plunger
means and be retained therein, wherein said breakable end of said hollow
plunger means includes tapered shoulders which engage oppositely and
complementing shoulders of said resilient fingers, allowing forward
movement of said hollow plunger means to spread said resilient fingers
radially outward, said syringe further comprising an extending tab and a
receiving slot associated between an exterior of said hollow plunger means
and the interior of said barrel means, said extending tab and said
receiving slot oriented to lock together when said tab and said slot are
brought into alignment with each other within said barrel means, thereby
locking said hollow plunger means within said barrel means, wherein said
spring loaded needle means operatively dissociates from said barrel means.
13. A hypodermic syringe as claimed in claim 12, wherein said hollow
plunger means and said barrel means are substantially transparent, said
captured needle having a distinctive appearance to be readily seen through
said syringe plunger and said barrel means once ejected into said hollow
plunger means.
14. A hypodermic syringe as claimed in claim 13, wherein said hollow
plunger means includes an evacuated chamber to extract fluid from said
spring loaded needle means upon the dissociation of said breakable end of
said hollow plunger means.
15. A hypodermic injection system, comprising:
(a) an injection needle having a shaft with an axial passageway
therethrough, said shaft having a sharp end and a holder defining a raised
lip on another end;
(b) a cylindrical spring housing having an exterior surface, and resilient
legs spreadable radially outward on a first end, said cylindrical spring
housing having exteriorly located attachment tabs extending radially
outward, a first sealing means for providing a seal between said
cylindrical spring housing and said shaft of said injection needle, an
opening on a second end of said cylindrical spring housing to receive said
shaft of said injection needle while retaining said holder, said resilient
legs having radially inwardly positioned hooks sized to engage and hold
said raised lip of said holder of said injection needle when said shaft of
said injection needle is forwardly positioned within said cylindrical
spring housing, said hooks having inwardly tapered shoulders;
(c) a coiled spring means positioned axially within said cylindrical spring
housing between said holder and said second end of said cylindrical spring
housing, said spring means exerting a repulsive force between said holder
of said injection needle and said second end of said cylindrical spring
housing less than the retaining force exerted by said hooks of said
resilient legs, thereby retaining said injection needle within said
cylindrical spring housing against said repulsive force of said spring
means;
(d) barrel means for engaging and holding said cylindrical spring housing,
said barrel means including slots and a groove sized and positioned within
an interior of said barrel means to receive said extending tabs of said
cylindrical spring housing and said cylindrical spring housing having a
second sealing means to provide an air tight seal between said exterior of
said cylindrical spring housing and said interior of said barrel means,
said interior of said barrel means shaped sufficient to engage said
cylindrical spring housing and allow said resilient legs to flex radially
outward; and
(e) a plunger sized to be received concentrically within said barrel means,
said plunger having a hollow axially located chamber therein, and having a
frangible end and outwardly tapered shoulders adjacent to said frangible
end, wherein said frangible end dissociates from said plunger and is
ejected into said chamber when said outward tapered shoulders forcibly
engage said inwardly tapered shoulders of said hooks of said resilient
legs, spreading said resilient legs outwardly and disengaging said hooks
from said raised lip of said injection needle, thereby allowing said
frangible end to dissociate under a predetermined normal force between
said holder of said injection needle and said frangible end, and allowing
said coiled spring means to eject said injection needle from said
cylindrical spring housing into said chamber within said plunger.
16. A hypodermic syringe system comprising:
(a) a syringe barrel having an attachment end;
(b) a syringe plunger including a frangible end sealing an interior cavity,
said syringe plunger sized to be received within and slide through said
syringe barrel;
(c) an injection needle; and
(d) a spring holding means including a spring, said spring holding means
associated with and held by said syringe barrel, for holding said
injection needle and selectively retracting said injection needle into
said interior cavity of said syringe plunger when said syringe plunger
abuts against and moves beyond a portion of said syringe barrel, causing
breakage of said frangible end, and allowing said frangible end of said
syringe plunger to separate, and wherein said spring holding means can
easily be attached and removed to and from said barrel means. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
This invention relates generally to hypodermic needles, and particularly to
hypodermic needles that are particularly suited for quickly and
effectively removing the sharp injection needle which poses a serious
health threat.
Various types of hypodermic needles currently exist in the art, with the
object being to provide a protective cover or cap over the possibly
wound-inflicting needle. Needles found in hypodermic syringes must be very
sharp to quickly and easily puncture the skin of the patient in order to
provide medicinals beneath the layer of skin. Additionally, the hypodermic
needle is usually very thin and hard to see, especially in low-light
conditions. Oftentimes, doctors and nurses accidentally prick themselves
with the needle, either prior to or after an injection of a patient.
Pricking oneself prior to the injection of a solution does not present much
of a health risk, since the needles to be used are usually sterilized.
Also, hypodermic syringes usually come with a needle cap which is secured
over the top of the needle to prevent the accidental puncturing of skin.
When the doctor or nurse takes off the needle cap, exposing the needle,
there is usually little risk of being injured by the needle. However, upon
placing the needle cap back onto the needle, oftentimes the fingers can be
pricked by a slight visual miscalculation or by a motorneuro mistake. The
consequences of this type of accident are more extreme.
Since the needle has already punctured the skin of the patient, blood and
body fluid along with the viruses or bacteria which may be found in the
patient could possibly be transferred to the healthcare provider by a
single accidental prick.
Various types of diseases previously known could be conveyed by such an
accident, including hepatitis and cholera.
In the last decade, an even more menacing and lethal virus, the Acquired
Immunity Deficiency Syndrome, or AIDS virus, is easily communicated by
such an accidental and catastrophic event. Since there is no known cure
for AIDS at this time, a great deal of care is required to prevent the
accidental prick of the health care provider by a hypodermic needle which
has previously been used on a patient.
Many types of syringes have been developed in an effort to address this
problem yet allow the ease of use of more conventional hypodermic needles.
Many of those devices are herein described below:
U.S. Pat. No. 3,134,380 issued to T. Armao on May 26, 1964 discloses a
hypodermic syringe needle having a shield which need not be removed prior
to the use of the needle and which can be disposed of along with the
needle itself. Holes are provided near the end of the shield to permit the
escape of air as the shield is collapsed allowing the needle to protrude
through the protective caps. The cap is held in an extended position by a
spring which yields upon injection.
U.S. Pat. No. 3,890,971 issued to T. A. Leeson on June 24, 1975 discloses a
safety syringe for one time use including a plunger which is lockable by
detent members and slidably needle cap which is also permanently lockable
to prevent reuse. The needle cap slides over the exterior of the syringe
barrel and over the fixed needle.
U.S Pat. No. 4,367,738 issued to R. Legendre on Jan. 11, 1983 discloses a
pre-filled syringe having spikes upon the plunger rods to prevent the
withdrawal of the plunger from the syringe barrel. No means is disclosed
for protecting the tip of the needle from accidental pricking.
U.S. Pat. No. 4,416,663 issued to R. N. Hall on Nov. 22, 1983 discloses a
self sterilizing needle, wherein a capsule containing sterilizing fluid
and having perforated ends of flexible material with elastic memory
tendencies for self sealing after actual penetration by the forward end of
the needle. The capsule is coaxially and slidably received over the
forward end of the needle with the forward exposed end of the needle
slidably penetrating one end of the capsule and perforation for
sterilizing of the needle. A syringe is provided for axially urging and
positioning the capsule outward to its original position of rest. Then,
the exposed end of the needle is again enclosed in the capsule for
sterilization when the hypodermic penetration force is removed.
U.S. Pat. No. 4,631,057 issued to C. B. Mitchell on Dec. 23, 1986 discloses
a needle coupled to a syringe barrel, wherein a needle guard is mounted on
the barrell for movement from a retracted position in which the guard does
not shield the needle to an extended position in which the guard shields
the needle.
U.S. Pat. No. 4,695,274 issued to R. L. Fox on Sept. 22, 1987 discloses a
safety needle attachment wherein the needle is initially and entirely
surrounded by a protecting jacket which is releasably interlocked with a
holder. When the needle is to be used, an interlocker is released and the
jacket is effectly telescoped over the holder to project the needle
through a membrane over the end of the jacket to a working position.
U.S. Pat. No. 4,702,739 issued to N. M. Milorad on Oct. 27, 1987 discloses
a hypodermic needle having a sleeve extending from a holder protectively
covering the needle so that the sleeve can be placed against the body part
where injection is to occur and with the needle tip end proximate the body
part. By sliding the holder toward the body part a detent restraint
holding the sleeve in an extended position is overcome and relative
retraction movement effected therewith.
U.S. Pat. No. 4,731,068 issued to J. E. Hesse on March 15, 1988 discloses a
non-reloadable syringe wherein the plunger is permitted to be withdrawn
for purposes of loading the syringe and permitted to be urged forward to
discharge the contents of the syringe. However, means is provided wherein
subsequent retraction of the plunger assembly is inhibited to prevent
further loading and use of the syringe.
U.S. Pat. No. 4,735,618 issued to J. Hagen on April 5, 1988 discloses a
protective enclosure for a hypodermic syringe needle formed by a tubular
sleeve sized for friction fitting engagement over the barrel portion of
the syringe. A needle guard portion is located at an opposed end and
pivotally removable arms operate to permit the needle to pass through a
central channel of the needle guard.
U.S. Pat. No. 4,737,144 issued to P. V. Choksi issued April 12, 1988
discloses a syringe system comprising a tubular barrel and a sleeve
mounted on the barrel to slide lengthwise from a retracted position in
which the needle is exposed, and an extended position in which the sleeve
extends protectively about the needle.
U.S. Pat. No. 4,737,150 issued to H. Baeumle on April 12, 1988 discloses a
tube-cannula syringe, the first cannula being disposed so as to be
displaced relative to the second cannula to be removable or displacable in
the longitudinal direction of the syringe.
U.S. Pat. No. 4,738,663 issued to David E. Bogan on April 19, 1988
discloses a sleeve guide having a pair of fasteners with cavities formed
in them that fit over the flange which are located on hypodermic syringes
for grasping in the user's fingers. The guide in the retracted position
prevents the accidental pricking by the needle.
U.S. Pat. No. 4,743,233 issued to Michael B. Schneider on May 10, 1988
discloses a slidable sleeve over a syringe barrel that is connectable in a
first position extending over a hypodermic needle and that is
reconnectable in a second position along the syringe barrel to expose the
needle for use.
U.S. Pat. No. 4,747,829 issued to J. Jacob et al on May 31, 1988 discloses
a pre-filled syringe with a retractable needle. A barrel of the syringe is
removable within a casing from a remote pre-injection position to a
forward injection position and back again. The barrel is moved forward
allowing the needle to pass through an opening in a cap prior to
injection.
U.S. Pat. No. 4,747,830 issued to W. W. Gloyer et al on May 31, 1988
discloses a syringe having a hollow barrel formed at the distal end to
receive an injection piston carried by the plunger member which allows the
needle to also to retract within the barrel by extracting the piston.
U.S. Pat. No. 4,752,290 issued to J. J. Schramm on June 21, 1988 discloses
a tubular shield which is adapted to protect users from injury. The
tubular shield cooperates with the raised surfaces on the body of the
medical appliance to be protected.
U.S. Pat. No. 4,755,170 issued to T. A. Golden on July 5, 1988 discloses a
protective sealing device comprising a block with which a sharp end of the
needle can be held within to prevent accidental puncture. Also disclosed
is a retaining shield which can be retracted over the needle to prevent
accidental puncture.
U.S. Pat. No. 4,772,272 issued to B. C. McFarland on Sept. 20, 1988
discloses a protective sleeve for a hypodermic needle which sleeve is
completely dissociable from the hypodermic syringe. The protective sleeve
is moved over the needle protecting position to the needle injection
position solely by axially movement of the protective sleeve.
It is desirable that the hypodermic needle can be made available in a safe
condition prior to injection so that the health care provider will not
accidentally prick his finger and require a new sterilized needle prior to
the injection of the patient. It is also a requirement that after
injection using the hypodermic needle, that the needle can be safely and
easily discarded without representing a continued health risk to anyone
who may encounter the hypodermic needle, either on the premises of the
health care facility, or in transit or arrival at the refuse collection
area or dump.
There is potentially a great interest in the health care industry to
manufacture, sell, distribute and use a hypodermic needle that provides
the type of safety as described above. It can be easily operated using one
hand, proves to be completely reliable, and is easily and cheaply
manufactured, yet still has a great deal of versatility for various
applications using various needles in diameter and length.
The features described above as being desirable above for hypodermic
syringes are all provided for by the present invention.
SUMMARY OF THE INVENTION
The present invention is embodied in an approved hypodermic syringe system
which is entirely safe prior to injection due to a protective cover tip.
Furthermore, after injection, the hypodermic syringe system is entirely
safe, since the health care provider, using one hand, can retract the
needle into an isolation container which can be easily and safely
discarded, preventing the injury or transmission of any dangerous viruses
or bacteria. In addition, the hypodermic syringe system is easily
manufactured, easy to use, and provides visual and audible confirmation
that the needle has been safely retracted after injection.
More particularly, the hypodermic injection system comprises a cylindrical
syringe housing, holding a retractable injection needle which can be
safely, quickly, and easily retracted within a specially designed syringe
plunger. Furthermore, the plunger is fixedly held within a specially
designed syringe barrel. The syringe barrel, plunger, and needle assembly
can be easily discarded without the dangers associated with an exposed
needle or needle that can be easily uncapped.
In more specific description of the invention, the injection needle has a
sharp end, a shaft with an axial passageway therethrough, and a holder
defining a raised lip. The injection needle is mounted within a
cylindrical spring housing having resilient fingers which are spreadable
radially outward on a first end and extending tabs extending radially
outward on an external surface of the cylindrical spring housing to
provide a mechanism for associating the cylindrical spring housing with
the syringe barrel. The cylindrical spring housing includes a first
sealing means for providing a seal between the cylindrical spring housing
and the holder of the hypodermic injection needle. Also, a second sealing
means for providing a seal between the cylindrical spring housing and the
syringe barrel is used.
An opening in a second end of the cylindrical spring housing is sized to
receive the shaft of the injection needle while retaining the holder when
both are forwardly positioned within the cylindrical spring housing. The
resilient fingers of the spring housing have radially inwardly positioned
hooks sized to engage and hold the raised lip of the holder of the
injection needle when the shaft of the injection needle is forwardly
located within the cylindrical spring housing. The hooks have inwardly
tapered shoulders so as to be easily spread by complementing and outwardly
positioned tapered shoulders of the syringe plunger.
A coiled spring is positioned axially within the cylindrical spring housing
between the holder and the second end of the cylindrical spring housing.
The spring exerts an expansive force between the holder of the injection
needle and the second end of the cylindrical spring housing, a force which
is less than the retaining force exerted by the hooks of the resilient
fingers, thereby retaining the injection needle within the cylindrical
spring housing against the expansive force of the spring.
The syringe barrel includes slots and grooves sized and positioned to
receive the extending tabs of the cylindrical spring housing and the
second sealing means to provide an air-tight seal between the exterior of
the cylindrical spring housing and an interior of the barrel. The interior
of the barrel is shaped sufficient to engage the cylindrical spring
housing and allow the resilient legs to flex radially outward.
The syringe plunger is sized to be received concentrically within the
syringe barrel and has a hollow, axially located chamber therein. The
syringe plunger has a frangible end with the outwardly tapered shoulders
adjacent to said chamber. The frangible end disassociates from the syringe
plunger and is injected into the chamber when the outward tapered
shoulders forcibly engage the inwardly tapered shoulders of the hooks of
the resilient fingers, thereby spreading the resilient fingers outwardly
and disengaging the hooks from the raised lip of the holder of injection
needle. The frangible end dissociates under a pre-determined normal force
between the holder of the injection needle and the frangible end. This
allows the coiled spring to eject the syringe needle from the cylindrical
spring housing into the chamber within the plunger.
The chamber located within the syringe plunger may be evacuated so that
when the frangible end breaks and ejects with the needle into the chamber,
any peripheral fluid is also drawn into the chamber and away from the
cylindrical spring housing.
Furthermore, an inwardly-oriented lip on the exterior of the plunger is
positioned so as to engage the complementing slot within the interior of
the syringe barrel when the plunger is in a fully-depressed position to
lock the plunger within the syringe barrel, preventing its removal and
access to the retained needle therein.
The holder of the needle can have a bright color (such as red) so as to be
visually distinctive within the transparent syringe barrel and syringe
plunger, so that the health care provider can readily determine that the
syringe is in a safe condition for transport or discard. The exterior of
the syringe barrel can also be fitted with a color-coded sizing ring,
which quickly and clearly identifies the size or capacity of the syringe
system.
In an alternative embodiment, the needle ejecting mechanism can be held on
the end of the syringe plunger. In that configuration, the needle is
retained by a frangible needle holder associated with the ejection end of
the syringe barrel. The hypodermic needle has a head which can be readily
grabbed by a modified end of the syringe plunger. Depression on the
syringe plunger dissociates the needle from the frangible needle holder.
Further depression on the syringe plunger allows a needle retractor to
pass by engaging detents, while a similar coiled spring ejects the needle
retractor which is now engaging the needle, ejecting the needle into the
interior chamber of the syringe plunger.
The hypodermic syringe system of the present invention provides for a
retractable needle which is durable, disposable, easy to manufacture,
prevents the accidental pricking after use, and provides for greater ease
of handling the hypodermic needle after use, including the subsequent
discarding of the device. The hypodermic needle is extremely simple in
construction, yet completing effective in injecting fluid below the skin,
subsequently becoming completely safe after the injection of the fluid
while the health care provider need only use one hand to retract the
needle, leaving his other hand free. Furthermore, his or her fingers may
remain in their relative positions to retract the needle.
Other aspects and advantages of the present invention will be apparent from
the following description of the preferred embodiments, taken in
conjunction with the accompanying drawings, which illustrate, by way of
example, the principals of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of the hypodermic needle of the present
invention;
FIG. 2 is a partial cross-sectional view of the hypodermic syringe of the
present invention, shown with its plunger proximate to the needle housing;
FIG. 3 is a cross-sectional view of the hypodermic syringe of the present
invention, with the needle housing, needle, and needle cap shown exploded
from the syringe barrel;
FIG. 4 is a cross-sectional view of the hypodermic syringe in the present
invention shown with the syringe plunger in a partially depressed position
within the syringe barrel;
FIG. 5 is a cross-sectional view of the hypodermic syringe of the present
invention shown with the syringe plunger in a fully depressed position and
the needle fully retracted; and
FIG. 6 is a cross-sectional view of an alternative embodiment of the
hypodermic syringe of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in the drawings FIGS. 1-6, wherein like numerals represent like
elements throughout, the hypodermic syringe 7 is best shown in exploded
view as FIG. 1. The main components of the syringe 7 are a standard
injection needle 9 having a specially-mounted holder 11 including an
enlarged lip 13, located posteriorly thereto. A coiled spring 15 rides a
shaft 17 of the injection needle 9 with an axially located passageway 19
therethrough. A cylindrical spring housing 21 includes a plurality of
radial spaced resilient fingers 23 which include inwardly engaging an
inferiorally positioned hooks 25 on the posterior end 27 of the spring
housing 21. A sealing means or washer 29 is sized to be received within an
inner cavity 31 of the spring housing 21.
The injection needle 9, including the enlarged lip 13 of the holder 11 can
be forwardly positioned within the inner cavity 31 of the cylindrical
spring housing 21. A cross-shaped opening 33 in a forward end 35 of the
spring housing 21 allows the shaft 17 of the injection needle 9 to extend
through the cross-shaped opening 33. The enlarged lip 13 is engaged by the
hooks 25 when forwardly positioned within the spring housing 21, causing
the resilient fingers 23 and hooks 25 to flex around the enlarged lip 13
and engage a top surface 37 of the enlarged lip 13.
The washer 29 provides a secure seal between the shaft 17 of the injection
needle 9 and the inner cavity 3 of the spring housing 21. Finally, a
gasket or O-ring 39 engages a circumferential groove 41, located midway
between the posterior end 27 of the spring housing 21 and the forward end
35 of the spring housing 21. This configuration can be more clearly shown
in FIG. 2, and also in FIG. 3, partially exploded from the other
components of the hypodermic syringe 7 of the present invention.
Also, shown in FIG. 3 is a needle cap 43, which engages a
forwardly-positioned second circumferential groove 45 of the spring
housing 21. The spring housing 21 has radially-extending bayonet tabs 47,
which provide locking engagement within bayonet slots 49 and a bayonet
groove 51, located within a tapered nose 53 of a syringe barrel 55.
Engagement between the spring housing 21 and the tapered nose 53 of the
syringe barrel 55 is easily accomplished by aligning the bayonet tabs 47
with the bayonet slots 49 and pushing the spring housing 21 through the
bayonet slots 49 and then rotating the bayonet tabs 47 within the bayonet
groove 51 to provide locking engagement therebetween. The bayonet tabs 47
may have slanted edges (not shown) on opposing sides and the bayonet
groove may have raised surfaces (not shown) to allow the slanted edges to
pass by the raised surface in one direction of rotation. This effectively
locks the spring housing 21 to the tapered nose 53 of the syringe barrel
55 in a racket-like manner.
The first tapered inner wall 57 within the tapered nose 53 of the syringe
barrel 55 provides sealing engagement between the spring housing 21 and
the syringe barrel 55, due to the tight fit of the O-ring 39 between the
spring housing 21 and the first tapered inner wall 57.
A plunger 59 is sized to be received within the syringe barrel 55 and
engages a plunger piston 61 of a conventional type commonly used with
syringe systems known in the art, except that a cylindrical cavity 71
extends therethrough, allowing a frangible end 65 to enter the cylindrical
cavity 71 of the plunger piston 61. The plunger piston 61 is positioned
over the associated frangible end 65 and is supported by a rim 67. The
length of the plunger piston 61 is such that outwardly tapered shoulders
68 extend through and above the passageway 63 of the plunger piston 61,
joining the frangible end 65. Between the outwardly tapered shoulders 68
and the frangible end 65 is a circumferential groove 69 of a defined
thickness of approximately 1/32 of an inch, which allows the frangible end
65 to dissociate from the outwardly tapered shoulders 68 upon a normal
force on the frangible end 65 of approximately two pounds or less in the
preferred embodiment. The circumferential groove 69 can, of course, simply
be a thinner construction of material allowing frangibility.
The plunger 59 includes the cylindrical central cavity 71 running axially
through the plunger 59 and adjacent to the frangible end 65. The
cylindrical cavity 71 has a diameter sufficient to allow the enlarged lip
13 and the holder 11 and the associated shaft 17 of the injection needle 9
to be injected into the cylindrical cavity 71 and need not be circular.
Furthermore, the cylindrical cavity 71 can be evacuated so as to allow the
vacuuming effect upon the dissociation of the frangible end 65 from the
outwardly tapered shoulder 68.
A plunger sleeve 73 defines the cylindrical cavity 71 while reinforcement
ribs 75 provide support to the plunger sleeve 73 and are associated with
the rim 67 to provide additional support when the plunger 59 is being
depressed. A pushing plate 77 is located on a posterior end 82 of the
plunger 59. The pushing plate 77 is sized sufficient to allow the thumb of
a normal person to properly depress the plunger 59 when associated with
the syringe barrel 55.
Also, finger retaining lips 79 are associated with the posterior end 81 of
the syringe barrel 55 so as to allow the index finger and middle finger to
grasp the finger-retaining lips 79 of the syringe barrel 55 while the
thumb presses upon the pushing plate 77. Grooves 83 or knurling may be
etched within the finger-retaining lips 79 or upon the pushing plate 77 to
provide a greater coefficient of friction between the fingers and thumb
and the finger retaining lip 79 and pushing plate 77, respectively.
Radially extending ratchet teeth 85 interrupt the reinforcing ribs 75 and
are posteriorly located while being posteriorly flared to allow the
ratchet teeth 85 to pass by an extending ratchet lip 88 defined by an
interior wall 89 of the syringe barrel 55. Upon full depression of the
syringe plunger 59 within the syringe barrel 55, the ratchet teeth 85 pass
by the ratchet lip 88. The ratchet teeth 85 flexibly pass by the ratchet
lip 88 and prevent the extraction of the plunger 59 from the syringe
barrel 55.
In operation, the syringe 7 of the instant invention, functions very much
like a conventionally known hypodermic syringe as found in the prior art.
However, after injection of the substance to be injected, the hypodermic
syringe 7 of the instant invention allows the dissociation of the
frangible end 65 from the outwardly tapered shoulders 68 of the plunger 59
and the radial flexing of the resilient fingers 23 so that the hooks 25
release the enlarged lip 13 of the holder 11 of the injection needle 9.
Since a circumferential space 91 exists between the resilient fingers 23,
and the inner wall 93 of the syringe barrel 55, the resilient fingers 23
can flex, releasing the holder 11. The resilient fingers will only flex
when inwardly tapered surfaces 95 of the hooks 25 are engaged by the
outwardly tapered shoulders 68 of the plunger 59. Such engagement takes
place when the plunger 59 is pushed through the syringe barrel 55 and the
frangible end 65 abuts against the top surface 37 of the holder 11. A
normal force of less than 2 pounds exerted between the top surface 37 of
the holder 11 and the frangible end 65 causes the frangible end 65 to
dissociate from the outwardly tapered shoulders 68 of the plunger 59.
With the resilient fingers 23 flexed radially outward, causing the hooks 25
to release the holder 11, the compressed spring 15 exerts an ejecting
force against the enlarged lip 13 of the holder 11, propelling the
injection needle 9 along with the holder 11, as well as the dissociated
frangible end 65 into the cylindrical cavity 71 of the plunger 59.
The above operation makes a very distinctive click sound alerting the
health care provider that the device is now safe.
Also, if the cylindrical cavity 71 is evacuated, a suction pulls any
residual fluids into the cylindrical cavity 71. Upon further depression of
the syringe plunger 59 into the syringe barrel 55, the ratchet teeth 85
engage the ratchet lip 88, preventing the plunger 59 from being extracted
from the syringe barrel 55.
The holder 11 can be a bright red or fluorescent color, while the plunger
59 and syringe barrel 55 can be manufactured from a transparent or
translucent material so that the retracted position is readily identified
in low light conditions and the needle is visibly safe for further
handling, transport or discard.
Also, an interchangeable identification ring 101 can be positioned around
the syringe barrel 55 so as to identify the hypodermic syringe 7 for
whatever purpose.
The plunger 59, syringe barrel 55, holder 11, spring housing 21, and needle
cap 43 can be made from a transparent or translucent plastic material.
However, the spring housing 21 does not necessarily have to be transparent
nor does the holder 11. Such materials and their manufacturer are well
known in the art and will not be further herein described. The plunger
piston 61 can be formed of a neoprene material sufficient to provide a
seal between the plunger piston 61 and the syringe barrel 55 and is also
commonly known in the art and will not be hereinafter described in more
detail. The shaft 17 of the injection needle 9 is of material known in the
art as well.
The O-ring 39 can be of a elastomeric material, just as the washer 29 may
also be of a resilient material, so as to provide a proper sealing effect
well known in the art. It should be noted that the spring housing 21 must
be formed of a durable plastic material which is resilient, so that the
resilient fingers 23 properly and radially outwardly extend in association
with the syringe plunger 59. The syringe plunger must be of a more
resilient or brittle material or have a proper thickness so as not to flex
inwardly when the frangible end 65 dissociates from the plunger 59. It is
important that the plunger 59 remains durable sufficient to cause the
resilient fingers 23 to move radially outward when the inwardly tapered
surfaces 95 of the hooks 25 engage the outwardly tapered shoulders 68 of
the syringe plunger 59. Specific examples of types of plastics and
thicknesses are not required, as these can be readily determined by those
ordinarily skilled in the art of plastics manufacture.
In an alternative embodiment, the mechanism responsible for ejecting the
injection needle 9 can be fully positioned within the syringe plunger 59.
As shown in FIG. 6, some slight variations in structure are necessary to
achieve similar if not identical results as described in the first
embodiment of the invention.
The injection needle 9 is held within a frangible needle holder 105, which
includes a frangible cone 107, which engages an enlarged section 109 of
the injection needle 9. The injection needle 9 has a length sufficient to
extend well within the syringe barrel 59 and has an extraction end 111,
which can be engaged by extraction hooks 113 of similar design as shown in
FIGS. 1-5.
A needle retractor housing 115 is located and held on an inward end 117 of
the syringe plunger 59, specifically held in place by detents 117, defined
within the interior wall 119 of the cylindrical cavity 71 of the plunger
59. The compressed spring 17 exerts a force between the needle retracting
housing 115 and the inner end 116 of the plunger 59. The force exerted by
the spring is not sufficient to force the needle retractor housing 115
past the detents 117.
In operation the plunger 59 is pushed into the barrel 55 having outwardly
tapered shoulders 121, which break the frangible cone 107, thereby
releasing the enlarged section 109 of the injection needle 9. Further
downward pressure on the plunger 59 forces the needle retractor housing
115 past detents 117, allowing the spring 15 to expand, pushing the needle
retractor housing 115 deep within the cylindrical cavity 71 and taking
with it the injection needle 9, because the hooks 113 grab the extraction
end 111 as the needle retractor housing 115 is moved deeper into the
cylindrical cavity 71 of the plunger 59. It should be noted that an extra
piston spacer 123 is required for proper operation, due to the injection
needle 9 extending within the syringe barrel 55.
Besides the above-identified differences, the second embodiment of the
invention functions substantially as the first and the materials necessary
for each of the components are similar to those materials as described in
the first embodiment of the invention.
It should be appreciated from the foregoing description that the present
invention describes an improved hypodermic needle with a retractable
needle which is simple in construction, yet completely effective in
retracting a needle once the needle has served its purpose in the
injection of fluids below the surface of the skin. The hypodermic syringe
of the present invention can be conveniently assembled from a minimum
number of separate parts, all of which can be manufactured with relatively
inexact precision, all of which are configured to facilitate compact and
efficient operation. The hypodermic syringe of the present invention can
be fully and safely operated by the use of one hand to retract the needle
and allow for safe handling, transport, and discard.
Although the present invention has been described in detail with reference
only to the presently-preferred embodiment, it will be appreciated by
those of ordinary skill in the art that various modifications can be made
without departing from the invention. Accordingly, the invention is
limited only by the following claims.
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