CA2096026C

CA2096026C - Hypodermic syringe

Info

Publication number: CA2096026C
Application number: CA002096026A
Authority: CA
Inventors: Michael J. Botich; Thor R. Halseth
Original assignee: MDC Investment Holdings Inc
Current assignee: MDC Investment Holdings Inc
Priority date: 1990-11-07
Filing date: 1990-11-07
Publication date: 2000-01-11
Anticipated expiration: 2010-11-07
Also published as: DK0568525T3; CA2096026A1; DE69030591T2; BG61026B1; NO305465B1; NO931662L; FI106536B; RU2095090C1; FI932069A; UA26322C2; WO1992008505A1; FI932069A0; JPH06500706A; BR9008048A; RO109160B1; EP0568525B1; GR3023268T3; DE69030591D1; US4994034A; JPH0649074B2

Abstract

A hypodermic injection system (7) with a retractable needle (9) wherein the needle (9) retracts within an interior cavity (71) of a syringe plunger (59); so that the needle (9) is safely and confinedly held within the plunger (59) for ease of handling and transport, while remaining safely therein, A cylindrical spring housing (21) has resilient fingers (23) which can capture a coiled spring (15) which biasly, holds a needle holder (11) against the retaining force of the resilient fingers (23), The plunger (59) has a frangible end (65), which, when engaging the resilient fingers (23) under a, pre-determined amount of force, dissociate while remaining outwardly tapered shoulders (68) spread the resilient fingers (23), allowing the coiled spring (15) to eject the needle (9) and its holder (11) into the interior cavity (71) of the syringe plunger (59).

Description

Wa0 92/0505 ~- ~°t:T'/U~90/05~162 HYPODERMIC ~YFtINGE
'rECT3NICA7C~ FIELD
this invention relates generally to hypodermic needles, and particularly to hypodermic needles that are particularly suited for quickly and effecta.vely removing the sharp injection needle which poses a serious health threat.
HACKGROTJND ART
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 accidenta5.ly prick themselves with the needle, either pxior to or after an injection of a patient..
Pricking oneself prior to the injection of a solution d9es not present much of a health risk,,since the needles to be used are usually sterilized. Also, hypodea:mic syringes usually.come with a needle cap which is secured over the tap of the needle ~:o prevent the accidental puncturing ..of skin.
~7hen the doctor or nurse takes off the needle cap, exposing the needle, there is usually little risk of being injured by the needle. ~iowever, upon placing the needle cap back onto ~l0 92/0545 ~~ ~ ~ ~ ~ ~ l~Cr/US~~I~6462 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 healthcar~e 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 Z5 catastrophic event. Since there is no known cure for ATDS
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.
l~iany types of syringes have been developed in an effort to address this problem yet allow th~~ ease of use of more conventional hypodermic needles.
P3any of those devices are herein described below:
U.S. ado. 3,134,380 issued 'to ~°: Armco on I~ay 26, 1964 discloses a hypodermic syringe needle having a shaeld which ... need not~be removed pxior to the use of~ the needle and which can be disposed of ~along'with the needle itself, Holes are provided near t:he end of the shield to permit the escape of air as the shield is collapsed allowing the needle to ~V~7 92/08505 3 ~ ~ ~ ~ ~ ~ ~ P~~lCJ590/06~1iG2 protrude through the protective caps. The cap is held in an extended position by a spring which yields upon injection.
U. S. Patent No. 3,890,971 issued to T. A. Leeson on June 24, 1975 discloses a safety syringe fox' one time use including a plunger which is loclcable by decent members and sl:idably needle cap which is also perananently lockable to prevent reuse. The needle cap slides over the exterior of the syringe barrel and over the fixed needle.
U. S. Patent No. 4,867,738 issued to gt. Legendre on January 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. Patent No.4,416,663 issued to R. N. Nall on November 22, 1983 discloses a self sterilizing needle, .
wherein ~ 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 forraard end of the needle with vthe forward exposed end of the needle sl~idably penetrating one end of the capsule and perforation for sterilizing of the needle. A syringe is provided for axially urging and positioning the capsule autward 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.

wc~ ~zios~o~ _ ~ ~ ~ (~ ~ ~ ~ ~ pc-rriu~~oios~sz -.
U. S. Patent No. 4,631,057 issued to ~. B. Mitchell on December 23, 1986 discloses a needle coupled to a syringe barrel, wherein a needle guard ias mounted on the barren 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. Patent No. 4,695,274 issued to R. L. Fox on September 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. Patent No. 4,702,739 issued to N. M. Milorad on October 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 past, where injection is to occur and with the needle tip end proximate the body part. ~1y sliding the holder toward the body part a decent restraint holding the sleeve in an extended position is overcome and relative retraction ' movement effected therew~.th. ' U, S, patent No. 4,731,068 issued to J. B. Hesse an March 15, 1988 discloses a non~reloadable syringe wherein the plunger is permitted to be withdraTan 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 ~"V~ 92/08505 5 2 ~ ~ ~ ~ ~ ~ P~,T/US90106~162 assembly is inhibited to prevent further loading and use of the syringe.
U, S. Patewt No. 4,735,61.8 issued to J'. Hagen on April 5, 1988 discloses a protective enclosure for a hypodermic syringe needle formed by a tubular sleeve sued for friction fitting engagement over the barz-el 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.
19 U. S. Patent 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. Patent 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 w longitudinal direction of the syringe.
U. S. Patent No. 4,738,663 issued to David E. Bogan on April 19, 2988 discloses a sleeve guide having a pair of fasteners with cavities formed in them that fit over the flange which are located on hypoe~err~nnic syringes for grasping in the user°s fingers. -v The guicle'in the xetract~d position prevents the accidental' pricking by the needle...
U. S. Patent No. 4,73,233 issued '~~ Michael B.
Schn~ider on May 7.0, 1988 discloses a slidable sleeve over a syringe barrel that is connectable in a first position if~ 92/08505 fCT/tU~90/05~162 r~ ~ .~ 5 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. Patent 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 1p . in a cap prior to injection.
U. S. Patent No. 4,747,83~ issued to W. W. Glover et al on May 31, 1.988 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. Patent 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. Patent No. 4,755,174 issued to T. A. Golden an July 5, 2988 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.punctuxe.
U. S. Patent No. 4,772,272 issued to ~. ~. Mcfarland on September 20, 1988 disclas~v a protective sleeve for a hypodermic needle which sleeve is completely dissociable WO 92/08505 7 ~ ~ L~ ~ ~ s'~' ~ PCT'Jt1~90/06~862 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. Tt.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 applicat~.ons using variousneedles in diameter and length.
The featu3-es described above as being desirable above for..hypoderanic syringes aye a:ll provided fox by the present invention... . ~ ~- .v W~ 92/0505 _ ~ ~~ (~ ~ ~ ~ ;~ 8 ~'CT/U590/0&162 OISCL~OSURE O.F THE TNV'ENTION
The present invention is embodied in an approved hypodermic syringe system which is entirely safe prior to injection due to a protective cover tap. 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, c~uic3cly, and easily retracted within .a specially designed syringe plunger. Furthermore, the plunger is fixedly held within a specially designed syringe barrel. ~'he 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 axa external surface of the cylindrical ~~ PC."f/'tJ~90/O~A6z Gr spring housing to provide a mechanism for associating the cylindrical spring housing with the syringe barrel. 1'he cylindrical spring housing inclT,xdes 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 pro~criding a seal betvaeen the cylindrical spring housing and ttae syringe barrel is used.
An opening in a second end of the cylindrical spring housing is sized to receive the shaft of the injection l0 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 Z5 shaft of the injection needle is for~aardly 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.
20 A coiled spring is positioned axially within the cylindrical spring housing betvaeen 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 25 force which is less than the xetaina.ng force exerted by the -hooves of the resilient fingers, thereby retaining the in3eation needle within the cyli~adrical spring housing against the expansive force of the spring.

1'VO 92/08505 ~ ~,~ ~ 10 hCT/~.1590/O~t62 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 off: the barrel. The interior of the barrel is shaped sufficient to engage the cylindrical spring housing and allow the resilient legs to flex radial:Ly 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 shaulders of the hooks of the resilient fingers, thereby spreading the resilient fingers owtwardly 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 chambe:r,' located within .the ~yrirage plunger may be a ~'~acuat:ed , so, that when , , the frangible end breaks and ej acts with the needle into the .chamber, any peripheral fluid is also drawn into the chamber and away from ~tYae cylindrical spring housing.

wo ~zio~sos 11~ ~ ~ .~ ~ ~ ~ ~crius~~>o~sz Furthermore, an inwardly-oriented Zip on the exterior of the plunger is pasitione:d so as to engage the complementing slot within the ini~erior of the syringe barrel when the plunger is in a fully--depressed position to loc3c the plunger within the syringe barrel, prevewting its removal and access to the retain~:d 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 ZO health care provider can readily determine that the syringe is in a safe condition far transport or discard. The exterior of the syringe barrel can also be fitted with a color-coded sizing ring, which quicl~ly 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 holdex 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 w syringe plunger allows a needle retractor to pass by . ~;n~aging detenta, while a similar coiled spring ejects 'the .. - beadle retractcir which is now engaging the needle, . a j acting the needle iota the interior chamber of the syringe plunger.
The hypadermic~syringe system of the present invention provides far a retractable needle which is durable, disposable, easy to manufacture, prevents the accidental W~ 92/0505 ~ ~ ~ b ~ ~ ~. 12 PCI'/US90/05462 pricking after use, and prova.des far greater ease of handling the hypodermic needle after use, including the subsequent discarding of the device. The hypodermic needle is extremely simple in consi~ruction, yet completing effective in injecting fluid below the skin, subsequently .
becoming completely safe after t:he injection of the fluid while the health care provider need only use on,e hand to retract the needle, leavin~q 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 DESCRIPTIOP1 OF THE bR~.YJIidGS
FIG. Z is an exploded view of t&ae hypodermic needle of the present invention;
FTG. 2 is a partial cross-sectional view of the hypodermic syringe of the present invention, showxa with its plunger proximate to the needle housings 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 a . - . . ~, . ._. :e .: -: ~ . : . ~ .
FIG. 4 is a cross-sectional view of the hvoodermic syringe in the present invention shown with the syringe plunger in a partially depressed position within the syringe vvo ~mo~sos ~ 3, ~ ~ ~~ ~ ~ , ~ ~~ rr/us~o/o6a~t barrel;
FIG. 5 is a cross-sectional view of the hypodermic syringe of the present inventa.on 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.
to BEST MODE FOFd CARRYING O'UT THE INVENTION
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 '~ 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 1.9 tharethrough. 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 axieans or washer 29 is ' sued to be received within an inner cavity 31 of the spring ' housing 21.
The injection needle 9, including the mnlarged lip 13 .
.. . . , . _. . ~ . . . .
of the holder 12 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 injectiow needle 9 to WO 92/0505 _. ~ , ~' ~ ~ 1 ~ P~CT/~J590f06~162 extend through the cross-shaped opening 33. The enlarged lip 13 is engaged by the hooks ~?5 when forwardly positioned within the spring housing 21, causing the resilient fingers 23 and hooks 25 to flex around the enlaxged lip 13 and I
engage a top surface 37 of the enlarged lip 13. .
Tine washer 29 provides a s~:cure 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 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. v Also, shown in FIG. 3 is a needle cap 43, which engages a forcaardly-positioned second circumferential graove 45 of the spring housing 21. The sgring housing 21 has radially-extending bayonet tabs 47, which provide locking engagement w~.thin 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 hushing the sprang housing 21 through the bayonet slots 49 25,... end then rota~:ing .'the bayori~t tabs ~7 within the bayonet _.., ~~roove~ 51 ~~to'..provide~ locking ex~gagein~nt thereb~tween. The bayonet tabs 4.7 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 wo ~zio~so~ ~ ~ ~ ~ 0 2 ~ ~c-~1~~90/o~s~2 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 walk. 57 within the tapered nose 5 53 of the syringe barrel 55 provides sealing engagement between the spring housing 21 anct 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 1a 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 15 positioned over the associated frangible end 65 and is supported by a rim 67. The length of the plunger piston 61 a.s 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 dissaciate from the outwardly 'tapered shoulders 68 upon a normal force on the ;frangible end 65 of approximately two pounds or less in thevpreferred em',bodiment. The circumferential~:groove 69 can, of:.course, simply be a thinner construction of material al5.owing ~rangibility.
The plunger 59 ~.ncludes the cylindrical central cavity 71 running axially through the plunger 59 and adjacent to WO 92/08SU5 ~ ~ ~ ~ ~ ~ ~ ~ 6 f'~'r'/lJS9U/Ufi~8~2 the frangible end 65. The cylindrical cavity 71 has a diameter sufficient to allow t;he enlarged lip 13 and the holder 11 and the associated shaft 27 of the injection needle 9 to be injected into the cylindrical cavity 71 and need not be circular. ~'urtherzr~ore, 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 gra:~p 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 tlne 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 _:-rretaining:lip-:.79:and pushing plate 77;:respectively'.
.. ~ Radially extending ratchet.~teeth 85 interrupt 'the _ reinforcing ribs 75 and are posterirarly located while being pc~s'teriorly.flared to allow the ratchet teeth. 85 to pass by an extending ratchet lip 88 defined by an interior wall 89 d1'~ 92/08505 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~C~f'/~1~90/0~462 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.
Tn aperation, the syringe J' 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 ,:v.
of the holder 11 of the injection needle 9. r ' 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 s8 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 3~ of the holder ll and the frangible end ~5 causes the frangible end 65 to dissociatwe from ~ the outwardly ta~aered shoulders 58 of tk~e plunger 59.
With the z-esilient fingers 23 flexed radially outward, causing the hooks 25 to release the holder 11, the W~ 92/08505 , , PCx'/U59~/06'iG2 1 f3 compressed, ~r~~ ~~ 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 saund 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 sg, 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 arad 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 p~irpose.
The plunger 59, syringe barrel 55, holder 11, spring housing 21., and needle cap 43 can be made from a transparent °
ox° 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 az~e we~.l known in the art and will not be further herein 1y~ 92/08505 19 ~ Q ~ ~ ~ ~ ~ Y~'r~u~9o~o6~162 described. The plunger pist on 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 a~.so 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 28 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 mrdinarily skilled in the art of plastics manufacture.
- In an alternative embodiment, the mechanism responsible 25- for electing the injection needle 9 can be .fully positioned within the ' syringe p~.unger 59. As :.hown ~ in ~'I~. 6, some slight variations in structazre are necessary to achieve similar if not: identical results as described in the first embodiment of 'the invention.

W~ 92/085U5 _ ? ~ ~ ~ ~ '~ ~ 2 O IPCd"/US90/06462 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 syrincre 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 autwardly 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 retradtor housing 115 past detents 117, allowing the sprang 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 exvraction end 111 as the needle f y5...»r~tracto~ housing 115 is waved deeper into the cylindrical ' , ~cava.ty 71 of the plunger 59~ It should be nated that an . i ~.
extra piston s~aacer 123 is required fog proper operation, due to the inje:~tion needle 9 extending within the syringe barrel 5~.

'VVO 92/0505 ~ ~ ~ I'CT/1J~90/06~4fi2 zs _ 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 l0 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 Z5 inexact precision, all of which are configured to facilitate compact and efficient operation. The hypoderanic syringe ~of the present invention can be fully and safely operated by the use of one hand to retract the needle and allow fox safe handing, transport, and discard.
20 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 25 invention is l:Lmited only by the following claims. ~ ,

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A hypodermic syringe system comprising a syringe barrel, a syringe plunger sized to be received within, and slide in, said syringe barrel, the plunger having a forward end and an interior cavity, a needle assembly movable from a projecting position to a retracted position and spring holding means including a spring, said spring holding means being held by said syringe barrel for holding said needle in its projecting position and for permitting movement of the needle into its retracted position in said interior cavity through the forward end of the plunger when the syringe plunger is pushed sufficiently forward within the syringe barrel, the forward end of the interior cavity of the plunger being covered by an integrally formed frangible end on the plunger such that the frangible end is caused to be broken when the syringe plunger moves beyond a predetermined portion of the syringe barrel to uncover said interior cavity and allow the needle assembly to be received therein.

2. A hypodermic syringe system according to claim 1, wherein the barrel is provided separately from the spring holding means prior to use, the barrel including attachment means for receiving the spring holding means to attach the spring holding means to the barrel.

3. A hypodermic syringe system according to claim 2, wherein said attachment means includes a locking mechanism for locking the spring holding means to the barrel.

4. A hypodermic syringe system according to claim 1, wherein the needle assembly comprises a needle having an annular rim for providing a radial abutment surface; said spring holding means comprises a housing for holding the needle assembly, the housing having axially-extending resilient fingers having a radially-inward abutment surface formed thereon for retaining said needle assembly in its projecting position; wherein the spring urges the rim of the needle assembly into abutment with the abutment surface of the fingers;

and said plunger has an engaging end which, on forward movement of the plunger past said portion of the syringe barrel, abuts against said resilient fingers and spreads them radially outwardly to release the rim of the needle assembly and enable the spring to move the needle assembly into its retracted position.

5. A hypodermic syringe system according to claim 4, wherein said frangible end separates from the syringe plunger when a predetermined normal force is exerted between the frangible end and said needle assembly.

6. A hypodermic syringe system according to claim 5, wherein said syringe plunger spreads said extending resilient fingers radially outwardly upon depression of the syringe plunger past said portion of said syringe barrel allowing said frangible end to urge against said needle assembly for receiving said normal force.

7. A hypodermic syringe system according to any of claims 1, 2 or 4, wherein said spring holding means is operatively disconnectable from a nose section of said syringe barrel.

8. A hypodermic syringe system according to any one of claims 1, 2, 3 or 4 the syringe further comprising ratchet means for engaging said syringe plunger with said syringe barrel, preventing separation of said syringe plunger from said syringe barrel after depression of the syringe plunger within the syringe barrel effecting retraction of the needle assembly.

9. A hypodermic syringe system according to claim 7 wherein the syringe barrel comprises a nose section having a threaded surface for mating with a complementary threaded surface formed on said spring holding means for securing said spring holding means to said nose section.

10. A hypodermic syringe system according to claim 3, further comprising said syringe barrel including a nose section, and said barrel is separate from the spring holding means and needle assembly, the barrel including attachment means to receive the spring holding means to attach the spring holding means and needle assembly to the barrel; and wherein said spring holding means includes at least one radially extending tab and said nose section of the syringe barrel includes at least one interior axial slot extending to an 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 the said radial slot, thereby securing said spring holding means to said nose section.

11. A hypodermic syringe system according to claim 1, wherein said spring holding means comprises a housing with resilient fingers having rearwardly extending tapered surfaces, and wherein the syringe plunger has complementary tapered shoulders adjacent said frangible end allowing forward movement of the plunger to spread the resilient fingers radially outwardly.

12. A hypodermic syringe system according to claim 1, 2 or 11, wherein said syringe barrel and said syringe plunger are substantially transparent, said needle assembly having a distinctive appearance to be readily seen through said syringe plunger and said syringe barrel when retracted into said interior cavity.

13. A needle retraction mechanism for a needle-bearing medical device having a barrel comprising a needle assembly movable between a projecting position and a retracted position, spring means providing a spring force for urging the needle assembly toward said retracted position, and needle retaining means for retaining the needle in said projecting position and for selectively releasing the needle assembly from the needle retaining means so that the spring means urges the needle assembly into its retracted position, said needle retaining means including axially extending, resiliently movable retaining members each movable radially from a normal retaining position for engaging the needle assembly to hold it in its projecting position and a released position in which the needle assembly is released to be moved by the spring means into said retracted position, the axially extending retaining members having rearward facing, tapered surfaces which cooperate with a complementary tapered forward surface of a sliding member slidably positioned within the barrel and arranged to contact the tapered surfaces of the retaining members to resiliently move the retaining members from their engaged position to a disengaged position to enable the spring means to urge the needle assembly into its retracted position in response to forward movement of the sliding member beyond a predetermined portion of the barrel.

14. A hypodermic syringe system comprising a syringe barrel having an attachment end, an injection needle, a spring holding means for selectively retaining said injection needle in a configuration projecting from the forward end of the spring holding means, and a syringe plunger sized to be received by and slide in said barrel, said syringe plunger having a frangible end sealing an interior cavity for receiving said needle when said syringe plunger abuts against said spring holding means causing breakage of the frangible end and allowing release of said needle by said spring holding means, said spring holding means being separately provided with complementary attachment means for engaging the attachment end of the barrel.

15. A needle retraction mechanism for releasably retaining a needle in a projecting configuration from the forward end of a needle-bearing medical device, wherein the medical device comprises:
a housing having a hollow barrel portion and a reduced-diameter hollow nose portion; and a sliding member slidably positioned within the barrel portion of the housing and having a tapered forward end formed thereon;

the needle retraction mechanism comprising:
a rim portion provided on a needle for forming a radial needle abutment surface;
a needle retaining member having a tubular forward portion extending axially within the nose portion of the housing, and a rear portion extending into the barrel portion of the housing, the rear portion of the needle retaining member comprising a plurality of axially extending fingers having inwardly-directed retaining surfaces formed thereon for abutment with the needle abutment surface, the fingers having tapered rear surfaces formed thereon;
and a spring positioned about the needle and compressed within the needle retaining member for urging the needle abutment surface against the retaining surfaces of the needle retaining member;
whereby compressive engagement of the tapered forward end of the sliding member against the tapered rear surfaces of the needle retaining member is effective to urge the fingers out of engagement with the rim portion of the needle and to allow the needle to be retracted into the device by expansion of the spring.

16. The needle retraction mechanism of claim 15 wherein said sliding member has a cavity formed therein for receiving the needle when the needle is released by the needle retaining member.

17. The needle retraction mechanism of claim 16 comprising a frangible member formed upon the forward end of the sliding member for covering the cavity, wherein the frangible member is configured to separate from the forward end of the sliding member when the forward end of the sliding member is urged against the needle retaining member for effecting retraction of the needle, such that the forward end of the cavity is thereby opened for receiving the needle.

18. The needle retraction mechanism of claims 15, 16 or 17, wherein the forward portion of the needle retaining member is provided with engagement means for securing the forward portion of the needle retaining member in engagement with the interior of the nose portion of the device, whereby the needle retaining member is initially provided as a separate assembly from the housing of the device.

19. The needle retraction mechanism of claim 18 wherein said engagement means is configured for locking engagement with the nose portion.