AU628814B2 - Rteractable hypodermic needle - Google Patents

Description

OP.I DATe 16/10/89 APN D 339/8 APPLN- I D 34399 89 Pci' v A0 6

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8 /1 8 89 1 91-1 NUMBER PCT/IAU89/00121 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCI) (51) InternationalI Patent Classification 4 International Publication Number,, WO 89/ 09075 A61M 5/ 32 p 5/34, A64M 5/315 Al (43) International Publication Date: 5October 1989 (05,10-89) (21) International Application Number; CTA89002 (74) Agent-, COWIE, CARTER 1-1ENDY; 71 Queens (22) International Filing Date: 21 March 1989 (21,03,89) RodMebunVC04(A) (81) Designated States;. AT, AT (European patent), AV, BB3, (31) Priority Application Numbers; P1 7385 BE (European patent), 130, Bj (QAPI patent). BR, 24498/88 CF (QAPI. patent), CC (QAPI patent), CH, CH (European patent), CM (QAPI patent), DE, DE, (Euro (32) Priority Dates; 22 March 1988 (22,03,8) pa aetDEF (EuropeanpantG 28 October 19$8 (28,10,U8) (OAPI patent), 0B, GB (European patent), HlUI IT (European patent), JP KP, KR, LK, bLJ, LU (Eurot (33) Priority Country: AU pean patent), MQ, MG, ML (OAPI patent),, MR (OA- PI patent), MW, NI., NL (European Patent), NO,.

R0, SD~, SE, SE (Europeani patent), SN (OAP! pa'~ (71) Applicant (for all designated States e.vcept DAYSA tent), SU, TD (OAP1 patent), TG (QAPI patent),, UIS, SEVENTY-FTHr PTY, LTD. [AU/AVI; 25 Haig street,, South Melbourne, VIC 3205 Published (72) Inventor;, and Withi International soarc/ repori, Invenlor/Applicant 6dr, US, only) KITE, John, Patrick Witlh amendeod cilms, (AU/AU]; 179 Gipps Street DOWb, NSW 2830 (AU), (14)Tltle., HYPODERMIC NIEL,,)L RETRACTOR A hypodorni gyrlng (10) hms a retract-kble needle1 18) 011fricd in A ficedl support (17) rwotied on~ the end o( the i qrng body The neccil (18) 13 attached to a needle holder (22) Which hits a conical head (26) on Its rorward end. X jpassage (30) in the holder enables the needle bore to conmmunicate t~itugf holes (1.91 in the holder (22) with the chamber 'th plurag4t and piston assembly 032) has it piston (33) with. a selilia clip 05) engaged thercwih. The piston (33) hasi a rorwardly extending tubular protion (19) def"tnn an opening with a tapcred wall (40) whIich engages over the head (246) to~ lock the head behind an abutmnen surface At the same ttne a diaphrigui (33) (mrned by the sealing cap ex.

tending across the tubular portion 039) Is ruptured so the chamiber (14)1Is no longer sealingly encloled, WO 89/09075 PCT/AU89/0012 I HYPODERMIC NEEDLE RETRACTOR Background of the Invention The present invention relates to a syringe and relates particularly to a hypodermic syringe incorporating a needle retractor.

syringes currently in use, have a fixed needle which is %ept or sealed with an, appropriate shield but which is otherwise permanently fixed to the syringe body for use. After the syringe has been used for the administration of a serum, An antibody or the like, a danger often exists with the. exposed needle of the. used syringe particular~ly if the needle, has not been. safely capped, Also, there is a danger, that a used syringe may be reused in which case a 'danger exists of infection from the now non-sterile syringe, Background Art Various solutions to the problem of an exposed needle of a, syringe, after use, have been proposed.

In United Stotes Patent No 406,8 to Hlaller, it is Proposed. to form the forward end of the barrel of the syringe a5 a breakable end wal, the canntlla mounted on the end wall boinq severable therefrom Upon retrac0tion of the plunger of the syringe. This,r however, can lead to the breakable end wall breaki-ng 11nadvertently during Operation of' the syringe, or as a rsult of forces apptied to the needle during use.

Various patent specificationp have suggested an arrangement whercby the needle of the Oyringe Is mounted in a, lh~b 4,nd the syringe plungar can, engage With the h~bt such as by a screw threaded action, to thereby withdraw the hub fromi the end of the syringe barrel to retract the noodle into thO barrel. such arrAngements as are zhown In. United States Patent No. 4,675,005 to tDeLuccia, tor 4,650,468 to Jennings, 4,710,170 to Naker ot. al.# 4,507,117 to Vining at.

41* and 4,592,744 to Walter. The structure of aLl1 these 3yringes is relatively complex, requiring SWO 89/09075 2 PCT/AU89/00121 arrangements for engagement of needles within needle holders, engagements of needle holders within syringe barrels so as to seal the needle within the barrel, means for engaging the plunger with the needle holder, generally by a rotational, screw threading or bayonet attachment and relatively complex operation procedures to ensure the disclosed systems are effective.

United States Patent No. 4,770,655 to Haber et.

al. discloses a syringe construction in which the piston assembly has a detachable stem and a needle capturing receptacle which is axially and distally movable in the cylinder. When the piston is moved to the most distal aspect of the cylinder it selectively engages the needle, The piston is withdrawn to relocate the needle from the distal end to the proximal cylinder end. The needle capturing receptacle is ,locked at the proximal end of the cylinder with the needle cannula retracted within and shielded by the cylinder. The stem is detached from the piston assembly and discarded, While the arrangement described is relatively simple, and therefore economical to produce, several actions are required in order to render the syringe relatively safe, one of those actions including breaking the stem from the piston assembly. It will be appreciated that un-intended stem breakage can easily occur through mis-use of the syringe, and if the stem is not broken, the syringe can be reused with relatively little difficultly.

Summary of the Invention It is desirable to provide an improved construction of hypodermic syringe which is economical to manufacture, has relatively few parts compared to the commonly used, fixed needle syringes, but allows the needle to be retracted and safely stored within the syringe for disposal It is another object oZ the present invention to provide an improved hypodermic syringe which, after use, cannot be reused without replacement parts, 3 WO 89/09075 PCT/AU89/00121 It is another object of the present invention to provide a hypodermic syringe which has a retractable needle and yet which also has a minimal free space.

It is also an object of the present invention to provide a hypodermic syringe having a retractable needle so as to lower the possibility of a used needle entering the skin of a person aft A the syringe has been used.

Additional objects, advantages and features of the invention will be set forth in the following description or will become apparent by practice of the invention. According to one particular aspect of the invention there is provided a syringe comprising a tubular body open at one end and substantially closed at the other end to provide a chamber, a needle mounting engaged with the said other end, a needle removably mounted in said mounting, the needle having an inner end formed with engageable means, a piston means axially movable within the body, said piston means having gripping means to selectively grip said engageable means When piston means is moved to the closed end of the body whereby subsequent movement of the piston means away from the said closed end draws the needle into the chamber, and a frangible diaphragm on the piston means which is broken with engagement of the engageable means with the gripping means.

In a preferred embodiment of the invention, the needle means includes a needle housing having a substantially axial passageway extending partway along the housing from one end. A hollow needle is secured in the passageWays and at least one hole in the housing wall communicates withth he passageway to allow fluid to pass from the chamber through the needle. The provision of the hole spaced from the inner end of 5 the needle means is an important feature which provides an extremely small minimal volume when the piston is moved to the end of the chamber.

The engaeeable means on th needle means parferably comprises a substantially conical or tapered head WO 89/09075

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PCT/AU89/00121 mounted on the needle means so as to provide a radially extending, annular shoulder. The gripping means, in the preferred embodiment, comprises an axially extending, hollow tubular part on the piston, the forward end of which has a tapering surface extending outwardly from a cooperating, annular shoulder. In use, when the piston is moved axially in the chamber towards the needle means, the tapering surface engages with the head of the needle means and snaps over the head so that the cooperating annular shoulder engages behind the head on the needle means.

In one form of the invention, the needle means is carried by a needle support removably attached to the needle mounting. This enables needle assemblies comprising the needle means and support to be replaced on a syringe body, Thus, the body and piston means can be reused with disposable needles. With this arrangement, the needle support and the needle mounting are provided with cooperating means for snap engagement thereof.

In an alternative arrangement, the needle support is fixed to the needle mounting for single use syringes.

In order that the invention will be more readily understood, one embodiment thereof will now be dIscribed with reference to the accompanying drawings.

Description of the Drawina Figure 1 is a cross sectional view of a hypodermic syringe in accordance with the present invention with the needle in the assembled position ready for use, Figure 2 is a view similar to Figure 1 but showing the syringe with the needle withdrawn into the chamber, Figure 3 is a cross sectional elevational view showing the syringe ready for disposal with the needle located within the plunger, Figure 4 is a detailed view of the needle end of the syringe showing the engagement of the piston with the needle, and Figure 5 is a cross sectional view taken along WO 89/09075 5 PCT/AU89/00121 the lines V-V of Figure 1.

Description of the Preferred Embodiment The drawings illustrate a hypodermic syringe having a retractable needle 18, In Figure 1, there is shown the syringe 10 comprising a syringe body 11 having a cylindrical wall 12 extending to an integral needle mounting 13 which substantially closes one end of the body 11. The cylindrical wall 12 defines a generally cylindrical chamber 14 which, in use, contains a liquid to be injected which is expressed from the chamber 14 through a passageway 15 in the needle mounting 13 and through the needle 18.

The syringe '10 is provided with a piston and plunger assembly 32 located in the chamber 14 and axially movable thereino. The assembly 32 includes a plunger body 34 fornmed by four radially extending elongated walls 34A terminating at an outer end in a finger piece 34B, Partway along the plunger body 34, radially inner edge of the walls 34A define a housing 34C.

A piston 33 is integral with the plunger 34 and is provided with a forwardly extending tubular portion 39 which communicates with the housing 34C. Tho tubular portion 39 terminates in a radially inwardly ex ndin 2 abutment surfaco 41 from which an outwardly tapering surface 40 extends.

The piston 33 is formed with an annular flange 36 defining aq annular groovo 37 forming a seat for a seal member 35,$ The soal mm ber 35 is preferably formed of a soft rubber material and contacts the inner surface of the cylindrical wall 12 of the syringe body 11 to form a liquid seal therewith. The seal member 35 is int the shape of a cap, a cntral portion of which constitutes a frangiblo diaphragm or mmbrane 38 engaged over the end of the tubular portion 39 of the piston 33. The seal member 35 therefore effectively seals the open enC of the chamber 14 of the syringe 10 and prevents fluid within th ehambevr 1 _I -6- WO 89/09075 PCT/AU89/00121 14 passing into the tubular portion 39 of the piston 33 and into the housing 34C.

The hypodermic needle 18 is fixed within an axial passageway 23 extending from one end of a needle housing 22. The passageway 23 communicates with a further passage 30 and substantially radially extending holes 29 which enable fluid to communicate from the syringe chamber 14 through the hollow needle 18. The needle support 17 is provided with an annular rib 19 which engages a corresponding groove in the needle mounting 13 to snap fit the support 17 in position. Alternatively, the needle support 17 may be fixed, as by gluing or welding, to the needle mounting 13.

Similarly, the needle housing 22 is formed with anannular rib 31 which engages with a corresponding groove in the needle support 17 to hold the hypodermic needle 18 in the operative position. The needle support 17 is formed at its forward end with an annular shoulder 24 which engages the end of the needle housing 22 and prevents forward movement of the hypodermic needle 18 relative to the needle support 17.

The inner end of the needle housing is formed with a conical head 26 defining an annular shoulder 28.

Xn use of the hypodermic syringe of the invention, the piston and plunger assembly 32 is moved relative to the syringe body 11 to expel liquid within the chamber 14 through the annular space 15 which exist between the needle housing 22 and the needle mounting 13, through the holes 29, the passage 30 and the hollow needle 18. The diaphragm 30 engaged over the end of the piston 33 prevents liquid passing through the tubular portion 39 forming the end of the piston 33.

AS the volume of the chamber 14 approaches its minimal volume, the conical surface 27 of the head 24 engages the diaphragm 38. Initially, and subject to the elasticity thereof, the diaphragm 38 deforms around the head 2 until the diaphragm ruptures.

Thereafter, the cnial surface 27 on the head 26 -7- WO 89/09075 PCT/AU89/00121 3$ engages the similarly shaped, cooperating surface on the tubular portion 39, expanding the end of the tubular portion 39 so that the head 26 snaps into the tubular portion 39. In this position, the abutment surface 28 engages the corresponding surface within the tubular portion 39 thus engaging the needle assembly with the piston and plunger assembly 32.

Movement of the piston and plunger assembly 32 axially in the syringe body 11 away from the needle mounting 13 causes the needle housing 22 and attached hypodermic needle 18 to be withdrawn into the chamber 14. Such movement causes the annular rib 31 on the needle housing to disengage from the corresponding groove. In an alternative construction, where no such rib is provided and the needle housing is frictionally held in the needle support 17, the withdrawing forces are sufficient to overcome the frictional holding forces. As the piston and plunger assembly 32 is continually withdrawn to the position illustrated in Figure 2, the needle, 18 is drawn fully into the chamber 14 so as to be located entirely therein.

The piston and plunger assembly 32 are then moved forwardly, or the syringe 10 is held vertically with the piston mounting uppermost, so that the needle 18 and needle housing 22 fall into the housing 34C within the plunger body 34. The piston and plunger assembly 32 can then moved to the position shown in Figure 3 so that the needle and needle housing are captively contained within the housing 34C for safe disposal; Xt will be appreciated that any attempt to reuse the syringe will fail due to the ruptured diaphragm 38 preventing pressure being developed, within the chamber 14. It will be noted that the housing 34C within the plunger body 34 has openings which communicate with atmosphere. Thus# the provision of the frangible diaphragm ensures that the syringt can be used once only without replacement of the seal m4mber.

The struqture of the syringe ol the present invention -8 WO 89/09075 PCT/AU89/00121 is substantially similar to the structure of fixed.

needle syringes currently in use. Accordingly, the present invention requires minimum re-tooling or modification of existing tooling to be put into practice.

Further, it is not necessary for the operator to go through a sequence of operations, such as twisting of the piston and plunger assembly relative to the syringe body, in order to engage the piston with the needle. The simple action of using the syringe automatically engages the piston with the needle and a simple withdrawing of the piston and plunger assembly retracts the needle into the syringe body.

It is envisaged that, subject to cost considerations, automatic retraction of the needle may be provided by mounting a compression spring on the syringe body and biasing the piston and plunger assembly to the outer position. With such a spring biasing arrangement, the operator uses the syringe to inject the fluid and the spring automatically acts to retract the piston and plunger assembly and the attached hypodermic needle into the syringe body without the need for specific operator action.

Claims (6)

1. 4. A syringe accordinig to any one of claims I to 3 wherein said aeedle mouals fs Carried by a needle SuIport remiovably attachecd to the nedle mounting, thle ,110014 support bt'llttding slolkkr Means to enigage correspond btig shoulder meansq on thle needle nicmans preveathtig MOVcent of the vecdle Muis axially of the support away fromt tho body. %0 A syrinige accordinig to, cla~ul 4 wherewin saild needle mieanis Csugages
2. 9. q 9 99 *4 ~9 .9 99 4. .9 9. 9 -9 9949 9 *99 99 99 99 9 4 *9 4 99 99 9 .9 9* 9 .9 4 .9 9, .9 99$ 9 4, 99 9 99 9 9- 9* pi rolfor"L 7 MY 119 i: I within an axial bore in the needle support, the bore diameter and length being such as to frictionally hold the neelic means in assembled position for use, 6. A syringe according to claim 4 wherein said needle means is provided with an enlargement which engages a corrcsponding groove in the needle support to hold the needle means in asscmblcd position for use. 7, A syringe according to claim 1 wherein said needle means comprises a hollow needle removably carried in the needle mounting, the needle having an inner end portion formed with an enlarged head, the inner end portion being either integral with or mounted on the needle. 8, A syringe according to any one of the preceding claims wherein the engaging means comprises a tubular extension on the piston means and terminating in a tapered surface extending radially outwardly from a radial abutvnent surface, the abutment surface adapted to engage behind a corresponding surface of the head means, 91 A syringe according to any one of the preceding claims whereln the plunger includes a needle receptacle open at a forward end through said piston to "0I: communicate with the engaging means.
3. 10. A syringe according to claim 9 wherein said receptacle is open to atmosphere external of the chamber 20 11 A syringo according to claim 9 or claim 10 wherein the receptacle Scomprises a substantially cylindrical wall substantially coaxial with the body and having a length greater than te length ofthe (c 1edle ;means and an inner diameter to freely receive the needle means, 12 A syringe according to any one of clams 1 to 11 wherein said frangible diaphragm is formed by a piston cap removably engaged with the piston a a9 meuns. 13, A hypodermic syringe comprising: a body having a cylindrical wall terminating at one end with needle Imounting and providing a chamber to recoive a liqulid to be injected; a needle movably mounted in said mounting and having a terminal ecd 4 +4- located in said chamber, said terminal cod having head means; a pi-ston slidably sealingly located within said chamber and longitudinally movable so, as to vary the voluime ofsi habr operator manipulable means cxtcndiog from said piston to enable a user to reciprocate said piston-, wherein said piston icludos gripping means to engage said terminal end o saidneedl whensaidchamber provides a min-imum volume, ota subsequent movement of said piston to increase the volume. of said chamber draws said neeqdle into said chamber; and housing means ill said, manipulable Means to recive the needle. drawn into said chamber,
4. 14. The syringe of claim 13 whereh said head means incue a ed with an abutment sufc and sai gripping mean incue a co-aicting abutmenrt, surface to engage the abutment surface of said head. 4i The syringe of ayneoclims 1or14 whecrein said piston includes a sieal membeir whidhidal sealingty enggs saidcyidrwladselm br :1':including a frangibloe diaphragm Qxtending across, said grippinig means and, which ia ruptured by said head means- whea said grippi g mean ismvd toeggn co'ntact with $aid Ongageable mnean 0,0 20 16" The syringe of any one0 of claims 13 to 15 further including a ne~edle 4$ssembly hiieorporatinig said livedlc, sai1d nedl assembly includiig, a needle, hoi;sitig within which1 s'i nKdl isaf se1sad eelehug bWintg provkded with said head mcans, a support to which said need le housing ks rem ovably, ahtacliqed, wisild ocedle. support beig attached to said neecdle mouitfng,
5. 17. The1 syringe of claim 16 wyhereinl said needle houising Is scented( to sal4 support by friction, which frictionl is overcome when said gripping me1anis draws theO ner-Hdl int aid chamber. 18 The syringe of clim 16 wherein said ticedle housing is mnounted la, said muppor by iterengaging mitntthr rib and groovo, 9~ A ficodic as~s(mbly to lie scetuted to it tieede tulottutiiig ot'a hypode ri1C ~4 syringe, said assembly including:, a nccdle support to be scured to said mounting, and being provided wi th a passage to communicate with thc interior of said syringe so as to rccive a liquid therefrom to be injected; a needle: housing mounted within said, passage and removably sccured to said support, said housing being provided with an undercut head which projccts into the interior of said syringe to a position whereat it can be snap-cngagcd by a piston assembly of the syringe, The needle assembly of claim 19 wherein said needle mounting is removably attached to said, support by an adhesive,,
6. 21. A syringe substantially as hInb r described withrfrnet h accompanying drawings. DATED this 7t0 day of July, 1992. :IjDAVSA SEXENTYbFIvrII PITY.LTD.- V'. ~~CAMTR SWITH I3EADLE 2 rnUwti Australia