U.S. patent application number 10/214449 was filed with the patent office on 2003-01-30 for medical devices with retractable needle.
Invention is credited to Botich, Michael J., Halseth, Thor R..
Application Number | 20030023205 10/214449 |
Document ID | / |
Family ID | 46248136 |
Filed Date | 2003-01-30 |
United States Patent
Application |
20030023205 |
Kind Code |
A1 |
Botich, Michael J. ; et
al. |
January 30, 2003 |
Medical devices with retractable needle
Abstract
A hypodermic injection system with a retractable needle wherein
the needle retracts within an interior cavity of a syringe plunger,
such that the needle is confined within the plunger. A spring
biases the needle rearwardly into the plunger, and a needle
retainer releasably retains the needle against the bias of the
spring. The plunger has a frangible end, which dissociates when the
plunger engages the needle retainer, allowing the coiled spring to
eject the needle into the interior cavity of the plunger. A body
fluid sampling embodiment employs the same functional elements
except the plunger is shorter and contains a linking that
communicates with a vacuum container. The container allows fluid
sampling and provides the structure to release the spring
retracting the needle. The retractable needle embodiment is also
employed with an insertion needle that guides a catheter tube below
the skin of a patient and into the vein, and allows retraction of
the insertion needle thereby avoiding accidental pricking of the
health care worker by the insertion needle.
Inventors: |
Botich, Michael J.; (Oxnard,
CA) ; Halseth, Thor R.; (Simi Valley, CA) |
Correspondence
Address: |
DANN DORFMAN HERRELL & SKILLMAN
SUITE 720
1601 MARKET STREET
PHILADELPHIA
PA
19103-2307
US
|
Family ID: |
46248136 |
Appl. No.: |
10/214449 |
Filed: |
August 5, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10214449 |
Aug 5, 2002 |
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09619901 |
Jul 19, 2000 |
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09619901 |
Jul 19, 2000 |
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09170649 |
Oct 13, 1998 |
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6179812 |
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09170649 |
Oct 13, 1998 |
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08692895 |
Jun 20, 1996 |
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6096005 |
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08692895 |
Jun 20, 1996 |
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08381203 |
Jan 31, 1995 |
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08381203 |
Jan 31, 1995 |
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08127962 |
Sep 27, 1993 |
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5407431 |
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08127962 |
Sep 27, 1993 |
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08017832 |
Feb 16, 1993 |
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08017832 |
Feb 16, 1993 |
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07656305 |
Feb 15, 1991 |
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5188599 |
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Current U.S.
Class: |
604/110 |
Current CPC
Class: |
A61B 5/150389 20130101;
A61B 5/150519 20130101; A61B 5/15003 20130101; A61M 2005/3231
20130101; A61M 25/0612 20130101; A61M 5/3202 20130101; A61M 5/3129
20130101; A61M 2005/3235 20130101; A61B 5/150351 20130101; A61B
5/150572 20130101; A61B 5/150648 20130101; A61M 2205/583 20130101;
A61M 5/3234 20130101; A61M 5/502 20130101; A61M 5/508 20130101;
A61M 25/0631 20130101; A61B 5/150732 20130101; A61M 2005/3241
20130101; A61B 5/154 20130101; A61M 2205/6081 20130101; A61M 5/5013
20130101 |
Class at
Publication: |
604/110 |
International
Class: |
A61M 005/00 |
Claims
1. A medical device, comprising: a barrel having a recess formed
adjacent a rearward end of the barrel; a needle; a spring biasing
the needle rearwardly a plunger axially displaceable within the
housing and operable to expel fluid from the barrel, wherein the
plunger comprises: a cavity for receiving the needle after use; a
flange on the rearward end of the plunger operable to displace the
plunger within the barrel; wherein the recess is configured to
receive the flange after use so that substantially the entire
plunger is disposed within the barrel after use so that the plunger
cannot be readily removed from the barrel after use; and wherein
after use the spring retracts the needle into the cavity in the
plunger.
2. The device of claim 1 wherein the recess is integrally formed
with the barrel.
3. The device of claim 1 wherein the device comprises a needle
holder holding the needle in a projecting position during use.
4. The device of claim 3 wherein the needle holder comprises a
breakable connection, and pushing forwardly on the plunger operates
to fracture the breakable connection to release the needle.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of co-pending U.S.
application Ser. No. 09/619,901 filed Jul. 19, 2000, which is a
continuation of U.S. application Ser. No. 09/170,649 filed Oct. 13,
1998, now issued as U.S. Pat. No. 6,179,812, which is a
continuation of co-pending U.S. application Ser. No. 08/692,895
filed Jun. 20, 1996, which is a continuation-in-part of U.S.
application Ser. No. 08/381,203 filed Jan. 31, 1995, now abandoned,
which is a continuation of U.S. application Ser. No. 08/127,962
filed Sep. 27, 1993, now U.S. Pat. No. 5,407,431, which is a
continuation-in-part of U.S. application Ser. No. 08/017,832 filed
Feb. 16, 1993, now abandoned, which is a continuation of U.S.
application Ser. No. 07/656,305 filed Feb. 15, 1991, now U.S. Pat.
No. 5,188,599. Each of the foregoing applications is hereby
incorporated herein by reference as if fully set forth herein.
FIELD OF THE INVENTION
[0002] This invention relates generally to retractable needle
systems and particularly to hypodermic syringes and intravenous
catheter insertion devices that are suited for quickly and
effectively removing the sharp insertion needle which poses a
serious health threat.
BACKGROUND ART
[0003] Various types of retractable needle systems currently exist
in the art, with the object being to provide a protective cover or
cap over the possibly wound-inflicting insertion needle. Insertion
needles found in intravenous catheter insertion devices and
hypodermic syringes must be very sharp to quickly and easily
puncture the skin and tissue of the patient in order to provide
medication directly into the vascular system. Additionally, the
insertion needle is usually very thin and hard to see, especially
in low-light conditions. It is possible for doctors and nurses to
accidentally prick themselves with the needle, either prior to or
after an insertion into a patient.
[0004] Pricking oneself prior to the insertion of a solution does
not present much of a health risk, since the needles to be used are
normally sterilized. Also, the insertion needle usually comes 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 removes
the needle cap, exposing the needle, there is little risk of being
injured by the needle. However, upon removal and placing the needle
cap back onto the needle, 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.
[0005] Since the insertion needle has already punctured the skin
and tissue of the patient, blood and body fluid containing viruses
or bacteria which may be found in the patient could possibly be
transferred to the health care provider by a single accidental
prick.
[0006] Various types of diseases previously known could be conveyed
by such an accident, including hepatitis and cholera.
[0007] In the last decade, an even more menacing and lethal virus,
the Acquired Immune Deficiency Syndrome, or AIDS virus, could be
communicated by such accidental and catastrophic event. Since there
is no known cure for AIDS at this time, a great deal of precaution
is required to prevent the accidental prick of the health care
provider by an insertion needle which has previously been used on a
patient.
[0008] Many types of syringes of one type or another have been
developed in an effort to address this problem yet allow the ease
of use of more conventional hypodermic needles.
[0009] A search of the prior art did not disclose any patents that
read directly on the claims of the instant invention. However, the
following U.S. Patents were considered related:
[0010] U.S. Pat. No. 3,046,985, issued to C. Saenz on Jul. 31,
1962, discloses a dental syringe adapter for concealing a needle of
the hypodermic syringe prior to use by a dentist. The needle is
retained in a housing until a syringe plunger is depressed and the
needle is pushed out of the protective housing instead of being
captively retained within a syringe body.
[0011] 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.
[0012] U.S. Pat. No. 3,306,290, issued to H. S. Weltman on Feb. 28,
1967, discloses a retractable needle syringe which retracts the
needle into a fluid-containing body and not into the syringe
plunger.
[0013] U.S. Pat. No. 3,890,971, issued to T. A. Leeson on Jun. 24,
1975, discloses a safety syringe for one-time use, including a
plunger which is lockable by detent members and a slidable 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.
[0014] 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 user from
accidental pricking with the tip of the needle.
[0015] 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.
[0016] 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 barrel 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.
[0017] U.S. Pat. No. 4,695,274, issued to R. L. Fox on Sep. 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 effectively
telescoped over the holder to project the needle through a membrane
over the end of the jacket to a working position.
[0018] 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 proximate to 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.
[0019] U.S. Pat. No. 4,731,068, issued to J. E. Hesse on Mar. 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.
[0020] U.S. Pat. No. 4,735,618, issued to J. Hagen on Apr. 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.
[0021] U.S. Pat. No. 4,737,144, issued to P. V. Choksi on Apr. 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, to an extended position in
which the sleeve extends protectively about the needle.
[0022] U.S. Pat. No. 4,737,150, issued to H. Baeumle on Apr. 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 displaceable in the longitudinal direction of the
syringe.
[0023] U.S. Pat. No. 4,738,663, issued to David E. Bogan on Apr.
19, 1988, discloses a sleeve guide having a pair of fasteners with
cavities formed in them that fit over the flange and which are
located in hypodermic syringes for grasping in the user's fingers.
The guide in the retracted position prevents the accidental
pricking by the needle.
[0024] 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.
[0025] 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.
[0026] U.S. Pat. No. 4,747,380, 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 retract within the
barrel by extracting the piston.
[0027] U.S. Pat. No. 4,747,831, issued to John C. Kulli on May 31,
1988, discloses a cannula insertion needle housing. The housing
includes a latch mechanism for extending and retracting the
needle.
[0028] U.S. Pat. No. 4,752,290, issued to J. J. Schramm on Jun. 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.
[0029] U.S. Pat. No. 4,755,170, issued to T. A. Golden on Jul. 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.
[0030] U.S. Pat. No. 4,772,272, issued to B. C. McFarland on Sep.
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 axial movement of the
protective sleeve.
[0031] An International Patent Application filed by K. W. Gaarde
and having a published number WO 89/00435, and a publication date
of Jan. 26, 1989, shows a hypodermic syringe with a retractable
needle in a needle holding mechanism which is integrally attached
to a syringe body.
[0032] It is desirable that the insertion needle of the hypodermic
needle or intravenous catheter device can be made available in a
safe condition prior to insertion so that the health care provider
will not accidentally prick his/her finger and require a new
sterilized needle prior to the insertion into the patient. It is
also a requirement that after insertion or sampling using the
insertion needle, that the needle be safely and easily discarded
without representing a continued health risk to anyone who may
encounter the insertion needle, either on the premises of the
health care facility, or in transit or arrival at the refuse
collection area or disposal facility.
[0033] There is potentially a great interest in the health care
industry to manufacture, sell, distribute, and use a hypodermic
needle, an intravenous catheter insertion needle and a vacuum tube
syringe that provides the type of safety as described above. It can
be easily operated, 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 and different sized vacuum tubes.
[0034] The features described above as being desirable for
hypodermic syringes, intravenous catheter insertion devices and
vacuum tube syringes are all provided for by the present
invention.
SUMMARY OF THE INVENTION
[0035] The present invention is embodied in an approved hypodermic
syringe system and intravenous catheter insertion device which is
entirely safe prior to insertion or sampling due to a protective
cover tip. Furthermore, after insertion or sampling, the hypodermic
syringe system and intravenous catheter insertion device is
entirely safe, since the health care provider, using one hand, can
retract the insertion needle into a tamperproof isolation container
which may then be easily and safely discarded, preventing the
injury or transmission of any dangerous viruses or bacteria. In
addition, both the hypodermic syringe system and intravenous
catheter insertion device are easily manufactured, easy to use and
provides visual and audible confirmation that the insertion needle
has been safely retracted after use.
[0036] More particularly, the hypodermic injection system comprises
a cylindrical syringe housing assembly, holding a retractable
injection needle which can be safely, quickly and easily retracted
within a specially designed syringe plunger. 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. The needle is preferably held inside the barrel
which is tamperproof.
[0037] In accordance with one aspect of the present invention, a
medical device is provided that has a housing from which a needle
projects for piercing the skin of the patient. After use, the
needle is retracted so that it is shielded against inadvertent
contact. The housing has a fluid cavity and a forward end. A
plunger is axially displaceable within the housing to expel fluid
from the housing. A biasing element displaces the needle from a
projecting position to a retracted position upon actuation of
retraction. When the plunger is pushed upon, the plunger operates
to release the needle for retraction by the biasing element.
[0038] Preferably the device also includes a needle retainer for
releasably retaining the needle in the projecting position. The
needle retainer may comprise a frangible or breakable connection
such that forward displacement of the plunger operates to fracture
the frangible connection to effectuate release of the needle. In
addition, the plunger preferably includes a cavity for receiving
the needle after retraction.
[0039] 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
[0040] FIG. 1 is an exploded view of the hypodermic syringe of the
present invention.
[0041] 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.
[0042] 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.
[0043] 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.
[0044] 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.
[0045] FIG. 6 is a cross-sectional view of the second embodiment of
the hypodermic syringe of the present invention.
[0046] FIG. 7 is an exploded view of the hypodermic syringe in the
third embodiment.
[0047] FIG. 8 is a cross-sectional view of the hypodermic syringe
of the third embodiment of the present invention shown with the
plunger ready for use.
[0048] FIG. 9 is a cross-sectional view of the hypodermic syringe
of the third embodiment of the present invention with the plunger
in the fully depressed position and the needle fully retracted.
[0049] FIG. 10 is an exploded view of the hypodermic syringe in the
vacuum tube blood sampling embodiment.
[0050] FIG. 11 is a full cross-sectional view of the hypodermic
syringe in the vacuum tube blood sampling embodiment shown with the
vacuum tube installed in the device and the hypodermic needle
extended ready for use and the cap removed.
[0051] FIG. 12 is a full cross-sectional view of the hypodermic
syringe in the vacuum tube blood sampling embodiment with the tube
removed and the needle retracted ready for disposal.
[0052] FIG. 13 is an exploded view of the intravenous catheter
insertion device of the present invention.
[0053] FIG. 14 is an exploded view of the intravenous catheter
housing assembly of the present invention.
[0054] FIG. 15 is an exploded view of the spring housing assembly
and insertion needle of the present invention.
[0055] FIG. 16 is a cross-sectional view of the intravenous
catheter insertion device in the present invention shown with the
plunger in a partially depressed position within the barrel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0056] The best mode for carrying out the invention is presented in
the terms of a preferred, second, third, fourth and fifth
embodiment. All five embodiments are similar in principle and
function, however, variations in structure segregate the five. The
preferred embodiment is shown in FIGS. 1-6, wherein like numerals
represent like elements throughout, the complete hypodermic syringe
7 of this embodiment is best shown in exploded view as FIG. 1. The
main components of syringe 7 are a standard injection needle 9
having a specifically 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 inferiorly 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.
[0057] 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.
[0058] The washer 29 provides a secure seal between the shaft 17 of
the injection needle 9 and the inner cavity 31 of the spring
housing 21. Finally, a gasket or O-ring engages a circumferential
groove 41, located midway between the posterior end 27 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.
[0059] 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
slots 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.
[0060] 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 0.031 inches (0.080 cm)
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.
[0061] 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.
[0062] 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.
[0063] 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.
[0064] 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.
[0065] In operation, the syringe 7 of the instant invention,
functions very much like a conventional 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.
[0066] 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.
[0067] 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.
[0068] The above operation makes a very distinctive click sound
alerting the health care provider that the device is now safe.
[0069] Also, if the cylindrical cavity 71 is evacuated, a suction
pulls the residual fluids into the cylindrical cavity 71. Upon
further depressions 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.
[0070] 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 of
discard.
[0071] Also, an interchangeable identification ring 101 can be
positioned around the syringe barrel 55 so as to identify the
hypodermic syringe for whatever purpose.
[0072] 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.
[0073] 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 sufficiently durable 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.
[0074] In the second 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.
[0075] 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.
[0076] A needle retractor housing 115 is located and held on an
inward end 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 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.
[0077] 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 detentes 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. In
other words, as shown in FIG. 6, a dead space is located at the
forward end of the syringe between the rearward end of the needle 9
and the forward end of the barrel 55. Fluid will remain in this
dead space at the end of the injection stroke unless the plunger is
configured to fill the dead space area at the end of the injection
stroke to expel the fluid from the dead space area. Accordingly, a
piston spacer 123 is attached to the forward end of the plunger 59
forward of and adjacent to the piston. The piston spacer 123 is
configured to cooperate with the dead space area to expel fluid
from the dead space area at the end of the injection stroke.
[0078] 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.
[0079] The third embodiment of the invention is illustrated in
FIGS. 7-9 and consists of a syringe barrel 55' having a partially
open end 125 and a fully opened end 127. The barrel 55' has finger
retaining lips 79' on the partially opened end 125 providing a
gripping surface for the user's fingers. Optionally, near the lips
79', a color coded ring 101 of sufficient resiliency and diameter
is slid over the exterior surface of the barrel 55' and retained by
friction to identify the particular syringe system. The open end
125 of the barrel contains bayonet slots 49' and grooves 51' or
threads for connecting other elements to the open end. The barrel
55' is transparent thus permitting the user to see the fluid
inside, allowing expulsion of bubbles of air that may be within the
liquid dispensed by the syringe.
[0080] A hollow syringe plunger 59' is slidably received within the
barrel 55' and is sized to move linearly back and forth without
restriction. The plunger 59' has converging taper 135 on one end
and an axial flange 136 on the other. The flange 136 has a radially
thinned slender section 138 at the interface with the barrel 55'
which actually breaks away if forced outwardly when the plunger 59'
is in its fully closed position contiguous with the barrel 55'.
[0081] A resilient barbed stopper 140 is tightly pressed into the
flange end of the plunger 59' completely closing the end thereof
allowing a hermetic seal inside the plunger. A frangible end 65' is
located on the tapered end 135' of the plunger 59' completing the
hermetic seal inside. The plunger 59' further contains an outwardly
extending raised circumferential band 142 around the flange end and
the barrel 55' has an internal recessed girdle 144 in a similar
location near the lips 79'. When the plunger 59' is fully depressed
and is recessed flush with the end of the barrel 55', the band 142
snaps into the recessed girdle 144 locking the plunger 59' into
place. This prevents the plunger from being withdrawn and as the
flange 136 is frangible, the closure becomes tamperproof even if an
attempt is made to pry the flange 136 from the barrel 55'.
[0082] On the converging tapered end 135 of the plunger, a piston
61' is positioned over a raised radial projection 146. This piston
is resilient in nature and seals the internal portion of the barrel
55' allowing liquids to be drawn inside and forced out by the
movement of the plunger 59'. Initially, the piston 61' is located
such that it is forward of the tapered end 135, however, when the
plunger 59' is fully inserted into the barrel 55', the piston 61'
is forced over the radial projection 146 into a secondary position
sealing tightly against the inside of the hollow of the barrel 55'
and exposing the tapered end 135 of the plunger 59'.
[0083] An injection needle 9' is positioned into the partially
opened end 127 of the barrel 59'. This needle 9' has an axial
passageway inside and is sharp on the exposed end and flat on the
other, or holder end. Spring holding means in the form of a holder
11', coiled spring 15' and spring housing 21' retain the needle 9'
and attach combined elements to the barrel 55'. The holder 11' has
a raised lip 13' on the end and the spring housing 21 is divided
into two pieces 21a and 21b that are pressed together. The front
portion 21a attaches to the barrel with bayonet tabs 47' into the
threads consisting of slots 49' and grooves 51' and partially
retains the spring 15'. The rear portion 21b retains the balance of
the spring 15' and fingers 23' and hooks 25' are integrally formed
therein in a frangible manner. The needle holder 11' is held in
place as the lip 13' interfaces with the hooks 15' on the fingers
23' maintaining compressive tension on the spring 15'.
[0084] In operation, the fluid medication or pharmaceutical is
drawn into the syringe 7' in a normal manner by the vacuum created
when the plunger 59' is withdrawn. After injecting the liquid and
the needle is withdrawn, the plunger 59' is forced completely into
the barrel 55'. As the tapered end 135 of the plunger approaches
the end of the hollow barrel 55', the piston 61' is forced back
over the raised projection 146 and simultaneously, the plunger
converging taper end 135 forcibly breaks the frangible section
between the resilient fingers 23' of the rear portion 23b of
housing 21'. This forcible bending outward of the resilient fingers
23' releases the holders raised lip 13' held by the hooks 25 at the
end of the fingers 23'. This releasing movement permits the
expansive force of the coiled spring 15' to break the frangible end
65' of the plunger 59' and drive the needle 9' frangible end 65'
and spring 15' into the hollow of the syringe plunger 59' fully
retracting the needle 9' and retaining it safely inside the syringe
7'. An audible clicking sound is heard when this action takes
place. As previously described, the plunger 59' is fully inserted
into the barrel 55' with the flange 136 flush with the open end 125
of the barrel 55' and is unremovable due to the locking into place
of the band 142 into the girdle 144. As it is seen, the elements
and function of this embodiment are basically the same with only
slight differences in structure to accomplish secondary operable
features.
[0085] In a fourth embodiment of the invention, the injection
needle retracting mechanism is basically the same and the
functional principal is identical except that instead of using the
syringe 7" for injecting fluids such as intramuscular absorbing
medication or intravenous pharmaceuticals, the invention is
directed to removing a fluid sample such as blood from the body.
The usual method to accomplish this procedure is to employ a system
that includes a hypodermic needle and a barrel including an
interconnecting needle that pierces a vacuum container or vial
drawing the sample into the container when the connection is made.
The same problem exists with this system as it exposes a sharp
hypodermic needle with only a removable cover for protection. The
inside interconnecting needle is of little danger as it is
completely surrounded by the barrel and is unaccessible to most
parts of the medical practitioner's body, at least without a
conscious effort.
[0086] The invention's embodiment for a device used in taking body
fluid samples is illustrated in FIGS. 10-12 and consists of the
same hypodermic needle 9", holder 11", coiled spring 15", spring
housing 21" complete with resilient fingers 23" and hooks 25" and
all of the associated elements. The syringe barrel 55" and the
plunger 59" however, differ somewhat in structure but retain the
basic function.
[0087] The syringe barrel 55" is cylindrical in shape and has a
fully open end 125' and an opposed partially opened end 127'. The
open end 125' may optionally contain a replaceable centering washer
129 that fits over the end 125' and that has a predetermined inside
diameter allowing a single barrel to be used with various diameter
fluid sampling receptacles. Finger retaining lips 79" are
positioned away from the end 125' in this embodiment serving to
assist the user in handling and manipulating the device and
allowing the washer 129 to be installed on the extreme end 125'.
The partially opened end 127' of the barrel contains the same
tapered nose 53' and tapered inner wall 57' except a straight
reduced bore section 131 is added extending the end slightly. On
the inside surface of the barrel 55", near the partially opened end
127', are located a pair of circumferential snap release
projections 133 that have a slightly smaller inside diameter, a
radial shape, and that are positioned parallel and close to one
another. These projections 133 are integrally formed with the
plastic barrel 55" and function as a retainer for the operating
parts described later.
[0088] The material of the barrel 55" may be opaque or translucent,
however, transparent is preferred to allow the sampling vial to be
viewed when it is disposed within the barrel. Additionally, a
color-coded identifying ring 101" may be slid over the exterior
surface of the barrel 55" and be retained by a slide fit to
identify the size of the syringe system such as its needle
diameter, length, etc.
[0089] A hollow syringe plunger 59" is slidably received within the
barrel 55". This plunger is configured to contain a converging
taper 135' on one end and a hollow linking needle 137 on the other.
The plunger's tapered end 135' includes a resilient seal 139 that
snaps over the plunger and becomes a closure between the plunger
59" and in the straight reduced bore section 131 creating a tight
hermetic seal with sufficient resistance to maintain the seal when
slid linearly in the bore.
[0090] The linking needle 137 is held within the plunger 59"
through a compression fit and is parallel with the inside of the
barrel 55" as shown in FIGS. 11 and 12. A needle boot 141 is
disposed over the needle 137 and stretches over a barbed projection
143 integral with the plunger holding the needle 137 on the inside
and providing a gripping surface for the boot. The boot 141 is
formed of a thin resilient material such as flexible silicone and
is sized to enclose and protect the needle when stored.
[0091] The needle end of the plunger 59" further contains an offset
extended flange 145 almost the same diameter as the inside of the
barrel 55" creating a stop and centering the plunger in the
barrel.
[0092] The middle portion of the plunger 59" is considerably
smaller in diameter than the barrel and defines a hollow plunger
sleeve 73' with a rim 67' near the tapered end 135'. This rim 67'
is basically the same structure as the preferred embodiment except
the outer edge is tapered sharply permitting the tip of the rim 67'
to be held in place between the peripheral snap release projections
133 located inside the barrel 55". When the plunger 59" is urged
toward the partially open end 125' of the barrel, the rim 67' has
sufficient resiliency to overcome its captivity between the
projections and snap away from the containment. A similar snap
action takes place when it is originally installed.
[0093] A sampling fluid vacuum container 147, vial or "B-D
VACUTAINER" as it is sometimes known in the medical field is
inserted inside the open end 125' of the barrel 55". The container
147 has a resilient perforatable seal 149 on one end and is domed
shaped on the other much like a test tube. The container 147 is
well known in the art and widely used to receive and store body
fluid samples. The container is normally fabricated of glass or
transparent thermoplastic and is evacuated on the inside allowing
the fluid to displace the vacuum eliminating the problem of
expelling trapped air.
[0094] The spring holding means associated with and positioned on
the barrel 55" is as previously described using the same hypodermic
needle 9", holder 11", and coiled spring 15". The spring housing
21" is slightly different and is preferably formed in two pieces
that are pressed together. The front portion 21a' interfaces with
the partially open end 125' of the barrel 55" and holds part of the
spring 15"; the rear portion 21b' of the housing retains the
balance of the spring 15". The fingers 23" and hooks 25" are also
integrally formed with the rear portion 2b'.
[0095] In operation, the container 147 is inserted loosely into the
barrel 55" and the hypodermic needle 9" is inserted, usually
intervenously into the patient. The container 147 is urged forward
into the barrel 55" where the linking needle 137 pierces the
container seal 149 and the vacuum within draws the fluid into the
container. The container 149 may be removed and replaced if another
sample is required however, when finished, the container is urged
further into the barrel 55" toward the partially open end 127' by
the practitioner thumb while grasping the lips 79" with the
fingers. This compressive force overcomes the resistance of the
snap release projections 133 holding the extended flange 145
allowing the plunger 59" to slide forward. The plunger converging
tapered nose end 53' forcibly spreads the resilient fingers 23" of
the rear portion 21b' of the housing 21" radially outward to
release the holder's raised lip 13". Thus, permitting the expansive
force of the coiled springs 15" to break the frangible end 65' and
extend the needle 9" and holder 11" into the hollow syringe plunger
59". This triggered movement fully retracts the needle 9" into the
hollow center of the plunger 59' and retains it in that position by
the continual urging of the coiled spring 15" thus repositioning
the needle 9" into a permanently protected and harmless location.
An audible clicking sound is emitted when this action is completed
and the container 147 may then be removed. Any liquid on the needle
is again harmlessly retained inside the syringe 7" and disposal may
be safely achieved. A color coded ring 101" as shown in FIGS. 1 and
4-6, may optionally be used in this embodiment if desired.
[0096] The fifth embodiment of the invention is an intravenous
catheter insertion device illustrated in FIGS. 13-16. Referring now
to FIGS. 13 and 14, the main components of the intravenous catheter
insertion device 150 is a catheter hub 152 comprising a flexible
catheter sleeve 154 having an interior shaft 156 with an axial
passageway wherein a standard insertion needle 9'" is
concentrically located. The insertion needle 9'" is mounted in a
spring housing assembly 21'", which engages a barrel 55'". A
plunger 59'" having an external ring portion 151 sized to be
received within the barrel 55'" for sealing purposes defines a
partially open or closed longitudinal cavity 71' extending
therethrough, allowing a frangible end 65" to enter the
longitudinal cavity 71' of the plunger 59'". For ease of
manufacturing, the longitudinal cavity 71' may have a longitudinal
slot 155 along a top side.
[0097] Between the frangible end 65" and the longitudinal cavity
71' are outwardly tapered conical shoulders 68' having a
circumferential groove 69' of a defined depth which allows the
frangible end 65" to dissociate from the outwardly tapered conical
shoulders 68' as described in the preferred embodiment. The
circumferential groove 69' can, of course, simply be a thinner
construction of material allowing frangibility.
[0098] A pushing plate 77' is located on a posterior end 164 of the
plunger 59'". The pushing plate 77' is sized sufficient to allow
the thumb or palm of a normal person to properly depress the
plunger 59'" when associated with the barrel 55'". Also, a finger
retaining area 158 is associated with the posterior end 156 of the
barrel 55'" so as to allow the index finger and thumb to grasp the
finger retaining area 158 of the barrel 55'" as the palm presses
upon the pushing plate 77'.
[0099] An extending rachet tab or tabs 160 are posteriorly located
on plunger 59'" while being posteriorly flared to allow the rachet
tab 160 to pass by a complementing recess or radial groove 162
defined by an interior wall 89' of the barrel 55'". Upon full
depression of the plunger 59'" within the barrel 55'", the rachet
tab 160 flexibly passes by the complementing recess or radial
groove 162 providing locking engagement thereby preventing the
extraction of the plunger 59'" from the barrel 55'". Also shown in
FIG. 14 is a catheter needle cap 166, which engages a
forwardly-positioned circumferential flange 168 of the catheter hub
152 to prevent accidental pricking by insertion needle 9'" prior to
use. Optionally, the needle cap 166 can directly engage a forward
portion of the spring housing assembly 21'". In order to removably
secure the needle cap 166 to the spring housing assembly 21'", an
external engagement groove may be present on the forward portion of
the spring housing assembly 21'" (similar to that present in the
preferred embodiment).
[0100] As shown in FIG. 15, the needle holder 11'" is affixed to a
distal end of insertion needle 9'" for placement in a first end of
spring housing assembly 21'". An opening 171 in a second end of the
spring housing assembly 21'" is sized to receive a housing plug 170
having a front end aperture 172 to allow passage of the shaft 17'
of the insertion needle 9'" and a circular cavity 176 having a
diameter that allows the spring 15'" to be coiled when the housing
plug 170 is forwardly positioned within the spring housing assembly
21'".
[0101] As shown in FIG. 16, the needle holder 11'" is retained by
resilient fingers 23'" of the spring housing assembly 21'" by
radially inwardly positioned hooks 25'" sized to engage and hold
the end of needle holder 11'". The spring 15'" is positioned
axially within the cylindrical spring housing assembly 21'" and
concentrically located around insertion needle 9'". The housing
plug 170 compresses the spring 15'" within spring housing assembly
21'" with the shaft 17' of insertion needle 9'" passing through a
central opening 172 of housing plug 170. The housing plug 170 is
permanently affixed to spring housing assembly 21'" by sonic
welding, bonding, Luer lock or other techniques known in the art.
The coiled spring 15'" is now positioned axially within spring
housing assembly 21'" between the retained needle holder 11'" and
affixed housing plug 170.
[0102] As shown in FIG. 13, the barrel 55'" has internal ratchet
teeth 161 sized and positioned to receive an external
circumferential locking groove 167 of the spring housing assembly
21'", and a transparent viewing lens 153 for the doctor or nurse to
view blood, indicating that the insertion needle 9'" and catheter
sleeve 154 are located properly under the skin. The spring housing
assembly 21'" has external extending tabs 169 that slide into
complementary longitudinal slots 175 of the barrel 55'" for
insuring proper alignment of the insertion needle 9'" when the
spring housing 21'" assembly is engaged with the barrel 55'".
[0103] In operation, the intravenous catheter insertion device 150
functions very much like the hypodermic syringe 7 of the preferred
embodiment. However, after injection of the insertion needle 9'"
and catheter sleeve 154 below a patient's skin, the insertion
needle 9'" is withdrawn when the health care provider sees blood in
the viewing window 153 wherein the plunger 59'" is pressed into
barrel 55'" allowing for the dissociation of the frangible end 65"
from the outwardly tapering shoulders 68' of the plunger 59'" and
the radial flexing or breaking of the resilient fingers 23'"
allowing release of the needle holder 11'" of the insertion needle
9'".
[0104] As shown in FIG. 16, a circumferential space 91' exists
between the resilient fingers 23'" and the inner wall 93' of the
barrel 55'", allowing the resilient fingers 23'" to flex or break
which releases the needle holder 11'". The resilient fingers 23'"
will only flex or break when inwardly tapered surfaces 95' of the
hooks 25'" are engaged by the outwardly tapered conical shoulders
68' of plunger 59'". As previously described and shown in the
preferred embodiment, engagement takes place when the plunger 59'"
is pushed through the barrel 55'" and the frangible end 65" abuts
against the end surface 174 of the needle holder 11'" which abuts
against a solidly compressed spring. A normal force of less than
two pounds exerted between the end surface 174 of the needle holder
11'" and the frangible end 65" causes the frangible end 65" to
dissociate from the outwardly tapered shoulders 68' of the plunger
59'".
[0105] When the resilient or frangible fingers 23'" flex radially
outward, the hooks 25'" release the needle holder 11'" causing the
compressed spring 15'" to exert an expansive force against the
needle holder 11'", propelling the insertion needle 9'" along with
the needle holder 11'", as well as the dissociated frangible end
65" into the longitudinal cavity 71' of the plunger 59'".
[0106] Similar to the other embodiments, the above operation makes
a very distinctive clicking sound alerting the health care provider
that the device is now safe.
[0107] Although not shown, the longitudinal cavity 71' may be
evacuated by application of a sealing plug exterior to plunger 59'"
so as to allow a vacuuming effect upon the dissociation of the
frangible end 65" from the outwardly tapered shoulder 68' of
plunger 59'". Furthermore, the needle holder 11'" can be a bright
or fluorescent color, while the plunger 59'" and 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 insertion needle 9'" is visibly safe for further handling,
transport or discard.
[0108] Additionally, although not shown, it may be envisioned that
the frangible end 65" may be replaced with the plunger 59'"
defining an aperture of sufficient size to allow the needle holder
11'", insertion needle 9'", and compressed spring 15'" to be
propelled into longitudinal cavity 71' when the resilient fingers
23'" flex or break when inwardly tapered surfaces 95' of the hooks
25'" are engaged by the outwardly tapered conical shoulders 68' of
plunger 59'", therefore performing the same operation as described
above.
[0109] Upon further depression of the plunger 59'" into the barrel
55'" the rachet tab 160 engages the rachet lip 162, preventing the
plunger 59'" from being extracted from the barrel 55'".
Additionally, at the end of resilient fingers 23'" are engaging
members 178 that engage grooves 180 located at the end of outwardly
tapered conical shoulders 68' of plunger 59'" further preventing
the plunger 59'" from being removed or extracted from barrel
55'".
[0110] Besides the above-identified differences, the fifth
embodiment of the invention functions substantially as the
preferred embodiment and includes all variations described in the
all of the above-described embodiments. The materials necessary for
each of the components of the fifth embodiment are similar to those
materials as described in the first embodiment of the
invention.
[0111] It should be appreciated from the foregoing description that
the present invention describes an improved hypodermic syringe and
intravenous catheter insertion device 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 or removal of fluids below the surface of the skin. The
retractable needle system 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 retractable needle system 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.
[0112] 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.
* * * * *