AU677574B2

AU677574B2 - Syringe

Info

Publication number: AU677574B2
Application number: AU29536/92A
Authority: AU
Inventors: Marius Van Der Merwe
Original assignee: Harwill Ind Pty Ltd
Current assignee: HARWILL INDUSTRIES Pty Ltd
Priority date: 1991-04-13
Filing date: 1992-12-01
Publication date: 1997-05-01
Anticipated expiration: 2012-12-01
Also published as: AU2953692A; NO942783D0; NO942783L

Description

OPT DATE 22/06/94 APPLN. ID3 29536/92 IIIIIIIIIIIIIfI AOJP DATE 25/08/94 PCT NUMBER PCT/GB92/02227 I II~Ill~ll ~~ll~l AU9229536 (51) International Patent Classification 5: (11) International Publication Number: WO 94/12229 A61 532 550Al(43) International Publication Date: 9 June 1994 (09.06.94) (21) International Application Number: (22) International Filing Date: 1I PCrIGB92/02227 ecember 1992 (01.12.92) (71)(72) Applicant and Inventor: VAN DER MIERWE, Marius IZAJZA]; 17 Anesta Street, Stellenbosch, 7600 Cape Province (ZA).

(74) Agent: DUMMLE=, Thomas, Ian, Peter; Dummett Copp Co., 25 The Square, Mlartleshamn Heath, Ipswich, Suffolk 7SL (GB).

2;(e cr (81) Designated States: AT, AU, BB, BG, BR, CA, CHi, CS, DE, DK, ES, F1, GB, HU, JP', KP, KR, LK, LU, MG, MN, MW, NL, NO. PL, RO, RU, SD, SE, US, European patent (AT, BE, CH, DE, DKC, ES, FR GB, GR, IE, IT, LU, MC, NL, PT, SE), OAPI patent (BF, BI, CF, CG, CI, CM, GA, GN, ML, MR, SN, TD, TG).

Published With international search report.

With amended claims.

c hC 4 RLoywvl hCIndusnes (P4-y) Li mid R. Vyje bowm hterlud P~epubb'c of Soufh AIG{ICL

SEC.

C' 113T 0J.

(54) Title: SYRINGE (57) Abstract The present invention provides a needle receiving member adapted to separate a needle from a syringe and to contain the said needle, the needle receiving member being characterised in that it comprises: a) an axially elongated member having an axially extending neele reeiving chamber therein and having axial aperture in a wall thereof through which the needle can be inserted at least in part .rns "sey and in that b) the needle receiving member incorporates means (22, 23, 26) for separating the needle from a syringe body.

The invention also provides a syringe in which the plunger (11) which drives the piston (10) of the syringe is formed so as to provide the needle receiving member, preferably in part of the plunger shaft which can be separated from the remainder of the plunger shaft by a frangible one use connection (14) o that the syringe can be disabled both by removal of the needle and breaking the plunger mechanism.

FOR THE PURPOSES OF INFORMATION ONLY Codes used to identify States party to the POTr on the front pages of pamphlets publishing international applications under the PCT.

Austria Australia Barbados Belgium Burkina Faso Bulgaria Benin Brazil Belanis Central Affican Republic Congo Switzerland C~te dtvoire Camertoon Czechoslovakia Czech Republic Germany Denmark Spain Finland FTa&= Gabon GB United Kingdom GE Georgia GN Guinea GR Greece Flu Hungary tE Ireland rr Italy JP Japan KE Kenya KG Kyrgystan KP Democratic People's Republic of Korea KR Republic of Korea KZ Kazakisan Ll Liechtenstein LK Sri Lanka LU Luxembourg LV Lacvia MC Monaco MD Republic of Moldova MG Madagascar ML MAUl MN Mongolia MR Mauritania MW Malawi NE Niger NL Nethsertanda NO Norway NZ New Ze4aan PL Poland Pr Portuga RO Romanla RU Ruasian F~edertion SD Sudan SE Sweden St Slovenia SK Slovakia SN Senegal TD Chbad TGI Togo TJ Tajikiatan IT Trinidad And Tobago UA Ukraine us United Statea of America UZ Uzbekistan VN Viet Nam 1 TITLE: SYRINGE The present invention relates to a syringe, notably to a saf ety syringe in which the syringe plunger and needle are rendered inoperative after use of the syringe, BACKGROUND TO THE INVENTION: syringes typically comprise a tubular body within which a piston head is moved axially by means of a plunger from a position at or adjacent the proximal end of the bore within the U 10 body to a position at or adjacent the distal end of the bore so as to dispense the contents of the space within the body ahea~d off the piston via a needle located at or adjacent the distal end of the body which is inserted into or under the skin of a *person. Many forms of syringe are known, but they all have these general features and the term syringe will be used hereinafter to denote a dispensing device of this type.

Once a syringe has been used to draw blood or other bodily fluid from a patient or to adinister a medicament or other material to a patient, problems arise in the disposal of the used syringe. Whilst the syringe can be constructed so that it can be dis-assembled and the individual components cleaned and sterilised for subsequent re-use, this is time consuming and costly. it is therefore the common practice to dispose of the used syringe to waste, for example into a strong plastic container which is disposed of by incineration or burial.

However, in handling the used syringe there is the risk that the handler may accidentally jab himself with the exposed end of the needle prior to or during insertion into the disposal container. Furthermore, the syringe is disposed of in an operative condition so that it can be retrieved from the disposal container for unauthorised re-use, for example to inject drugs or the like.

In order to reduce the risk of accidental jabbing with the used 2needle, it has been proposed to cut or break the needle off the syringe using a mechanical cutter such as that described in for example US Patents Nos 4965425 or 4961541, or using a pair of manual cutters with hardened steel blades. However, this will usually leave a sharp stump of the needle exposed which can still injure a user and machines to cut or breaK the needle are usually expensive and cumbersome and cannot readily be used away from sources of electric power.

It has also been proposed to supply the needle as a separate item enclosed in an axial sheath which must be removed once the needle has been mounted on the syringe before the syringe can be used. After use the sheath is re-applied axially to the needle to render the needle safe. It has been proposed in GB 2214082 A to incorporate a circumferential rib within the foot of such a sheath which engages with a circumferential groove in the mounting of the needle on the syringe so that the sheath when pushed fully home on -the needle engages the needle in such a manner that the needle can be separated axially from the syringe when the sheath is withdrawn axially from the syringe.

However, such sheaths suffer from the disadvantage that the user nvw:-7t locate the needle tip axially within the narrow bore of the sheath when mounting the sheath upon the needle and, there is a risk that he will stab himself with the tip of the needle in trying to do so.

In a variation of such a sheath it has been proposed, in for example GB 2217991 A, to mount a sheath having an axial slot in the wall thereof terminally upon the syringe, The sheath is pivotally mounted so that in one position it encloses the needle. When the sheath is swung aside, the needle passes transversely through the axial slot and is exposed for use.

After use, the sheath is swung back to enclose the needle.

However, such sheaths are intended to protect the needle before and after use, they are not intended to remove the needle from the syringe.

3 In a variation of such a syringe, it has been proposed in PCT publication No W092/12748 to provide the syringe with a removable plunger which has an axial bore therein. The side wall of the plunger is provided with an axial slot which provides a side entry into the axial bore. After use of the syringe, the plunger is withdrawn and the needle inserted transversely into the axial slot. The plunger is then pushed axially to drive the needle axially into the bore and to trap the needle within the bore. The plunger is then twisted to snap the needle from its mounting to leave the needle housed within the plunger and thus render the detached needle safe.

However, where the needle is mounted as a push fit upon the Sluer outlet to the syringe, such a device leaves the needle available for re-mounting upon the luer and thus permits re-use of the syringe.

Furthermore, such designs do not affect the operation of the syringe and replacement of the needle can thus render such syringes re-usable. It has therefore been proposed, for 20 example in US Patents Nos 5 004 460 and 4 923 443, to form the plunger with a one use construction so that the plunger can be rendered iroperative once the syringe has been used. Although the syringe is now inoperative, the problems of accidental jabbing with the needle and possible re-use of the needle remain.

In PCT Application W089/8468 it has been proposed that the plunger should incorporate a frangible section and an axial bore so that after use the plunger can be fully withdrawn and the exposed section of the plunger then broken off at the frangible section. The plunger is thus rendered inoperative and the separated portion can be used as a sheath for the needle which is inserted axially into the axial bore in the plunger. However, such a design requires the axial insertion of the needle into the bore of the plunger with its attendant risk of the user stabbing himself. In order to minimise the A risk of stabbing, it has been proposed, for example in PCT -4 Application WO 91/03269, to provide the needle mounting and the distal end of the plunger with co-operating means whereby the distal end of the plunger engages the needle mounting at the forward end of the plunger stroke and a spring or other means withdraws the needle axially into the hollow centre of the plunger- Such a mechanism is complex and costly to manufacture and still leaves the body of the syringe operative.

The need continues for a simple and effective means for rendering a syringe inoperative and for reducing the risk of :accidental injury to the user from the needle.

have now devised a means by which a syringe can be rendered inoperative at the same time as providing a simple means for disposing of the needle which overcomes the problem of handling and disposing of a sharp object.

SUIO4AR7, -OF THE INVENTION: :20 Accordingly, the present invention provides a syringe comprising a syringe body portion having an axial piston bore therein and slideably journalled for axial movement therein a piston member, a plunger adapted to aigage the piston member for axial movement of the piston member in the piston bore, said body portion carrying or being adapted to carry a needle through which the contents of the syringe body portion are to be discharged upon axial movement of the piston member within the piston bore, and a needle receiving member having an axially extending needle receiving chamber therein and having an axial needle entry aperture in a wall thereof through which the needle can be inserted into said needle receiving chamber, the needle being mounted or adapted to be mounted upon the syringe body by a breakable or demountable member whereby the needle can be detached from the syringe body, the plunger being formedi with a one use connection which can be separated so as to disable the syringe, characterised in that: a. the one use connection in the plunger member incorporates 5 a frangible portion whereby the plunger disabled by separation of the frangible portion so that the plunger member cannot withdraw the piston member in the piston bore, the frangible portion being configured so that the residues of the separated frangible portion provide opposed faces which are configured so that they can achieve axial foreshortening of the plunger after the separation of the frangible portion; and in that b. the plunger has an axial bore therein adapted to receive the detached needle and serve as the needle receiving chamber, a side wall of the plunger having an axial aperture therein through which part of the needle can be inserted into the axial bore.

It is preferred that the bore of the cylinder within which the plunger is journalled is provided with one or more inwardly projecting ribs or the like which engage in a corresponding circumferential recess or groove on the plunger, so that the *axially foreshortened plunger can be inserted into the cylinder .:20 and locked within the cylinder by the mutual engagement of the projections and the recesses or groove(s) when the free (proximal) end of the foreshortened plunger is pushed into the bore, preferably so as to leave no free end exposed to a user.

such foreshortening of the plunger thus renders the syringe wholly inoperative as well as providing a compact unit for disposal.

it will be appreciated that the projections on the syringe body can be located at the proximal end of the bore or syringe body, so that they engage the proximal end face of the foreshortened plunger rather than a recess formed in the side wall of the plunger. it will also be appreciated that the plunger may carry radially outwardly projecting members which engage a recess or circumferential groove in the wall of the bore. Such projecting members can be sharpened or acutely angled, for example to form sharp teeth or the like, which out into the wall of the bore to inhibit remaoval of the plunger once the 6teeth have engaged to wall of the piston -bore. In this case, the projections can be mounted on lever members which are actuated by the user to deploy the projecting members to engage with and cut into the wall when the plunger has been pushed fully home in the piston bore.

The axial bore in the proximal broken off portion of the plunger member which is separated from the syringe when the frangible portion of the plunger member is separated provides the needle receiving chamber so that the whole syringe can be broken down after use to demounit the needle and house it in the axial chamber within the broken of f portion of the plunger via insertion transversely through the axial slot in the wall of the plunger. The plunger/needle is then inserted into the bore 15 of the syringe and pressed fully home therein so that the plunger containing the needle is locked within the cylinder.

Apart from the features of the needle receiving chamber in the plunger member and the one use connection of the plunger greater detail below, the syringe of the invention can be of conventional design and construction. For convenience, the invention will be described hereinafter in terms of a radially symmetrical syringe having a cylindrical bore within which is journalled a piston for reciprocation by means of a plunger whose proximal end provides a thrust pad or button and whose distal end carries or bears against the piston, and from which fluid is discharged when a uses depresses the plunger to eject fluid in the bore of the syringe through an axially orientated needle carried on an axial outlet through the terminal cross wall of the syringe.

The needle can be mounted on the syringe by means of ;a breakable mounting and the end of the axial bore in the plunger shaft which is to be closest to the syringe during removal of the needle (the proximal end) can be provided with a metal or other strong rim which bears against the mounting as the needle 'receiving member containing the needle is flexed about the longitudinal axis of the syringe to cause the mounting or the needle to break. It is preferred to incorporate a break line in the plastic moulding which forms the mounting of the needle, for example a circumferential score or thinning in the wall of the mounting, so that the needle can be detached as a whole from the syringe. It may be desirable to provide the axial bore in the plunger member with means by which the needle is held firmly within the bore and axial movement of the needle with respect to the axial bore is minimised. The means for holding the needle can, for example, be provided by a tight fit between the needle and at least part of the internal walls of the axial bore or by a resilient member through which the shank :of the needle passes as a tight f it so as to minimise axial 15 movement of the needle within the axial bore during flexing of the needle.

V. Alternatively, the needle can be demountably mounted on the syringe body, for example by way of a push fit, screw or other ***mounting which is engaged by the axial bore. If desired, the :20 mounting can incorporate a breakable element as described above. Preferably, the mounting is a push fit of a needle support block upon an axial spigot outlet to the syringe body so that the needle as a whole is detached axially f rom the syringe body.

The axial bore in the plunger member is provided with a side, axial, needle entry port whereby the user moves the needle laterally with respect to the plunger member when inserting the needle into the axial bore in the plunger member, thus reducing the risk of jabbing himself axially with the needle tip.

Where the needle is to be detached by transver-se and/or axial movement of the needle mounting with respect to the syringe body, the axial bore in the plunger member is provided with suitable separating means located at or adjacent the proximal end of the needle entry port. Thus, where the needle is mounted by means of a screw fit mounting, the bore incorporates 8 a suitably shaped socket at its proximal end which engages a correspondingly shaped shoulder on the needle mounting so that they mounting can be unscrewed when the needle has been inserted into the axial bore. In a preferred embodiment, the mounting of the needle is by way of an axial push fit upon a boss or spigot at the distal end of the syringe body and the mounting is provided with one or more radial projections. These are to be engaged by a ramp or cam-like member at or adjacent the proximal end of the axial bore in the plunger member as the plunger member moves transversely with respect to the needle mounting. This action moves the needle mounting axially with respect to the syringe so that the needle is separated axially ji "from the syringe.

15 The radial projections on the needle mounting can be provided by the circumferential shoulder at the proximal end of a conventional mounting block carrying the needle or can be additional projections moulded into the mounting of the needle.

It will be appreciated that the radial projections on the needle mounting can be sloped to provided the ramp or camming member and that the projections on the wall of the axial bore in the plunger member need not then be ramped or cammed. It will also be appreciated that the same action can be achieved by means of an axially inclined groove which is engaged by a rib.

For convenience, this form of separation of the needle from the syringe will be described hereinafter in terms of a ramp member carried at or adjacent the proximal end of the axial bore engaging with the proximal end shoulder of the needle mounting.

It will be appreciated that the axial needle entry port in the wall of the plunger need not extend the full length of the needle receiving chamber axial bore in the plunger member, but may be axially shorter than the needle itself so that the user inserts the tip or distal portion of the needle transversely into the axial entry port and then moves the needle axially to 9 complete the insertion of the needle into the axial bore in the plunger member. However, it is preferred that the entry port extend for at least 50%, preferably from 75 to 100% of the axial length of the needle to be inserted through it, so that insertion of the needle is achieved substantially wholly by a transvrtrse movement between the needle and the plunger member.

The needle receiving chamber formed by the axial bore in the plunger member is orientated axially within the plunger member and extends for the full axial length of the needle it is to receive. However, as indicated above, the needle entry port in a side wall of the chamber need not extend for the full length of the chamber so that a needle once located within the chamber can not readily escape through the entry port.

The bore provi ding the needle receiving chamber can be merely a cylindrical bore ,,ithin which the needle is a loose fit.

However, it is preferred that the plunger member incorporate means which positively engage the needle or its mounting so that once inserted into the bore, the needle cannot readily be removed. For example, where the needle mounting incorporates a circumferential groove to provide the line of weakness at which the mounting is to break, the proximal end of the bore can have an internal rib which engages that groove to retain the needle in the bore once it has been broken away from the syringe. Alternatively or in addition, part of the bore can be formed as a tight fit upon the needle so that the needle is positively gripped and held within the bore.

The plunger for the syringe incorporates the one use frangible portion so that the plunger and the needle are both disabled after use of the syringe. The piston can be formed integrally with the shaft of the plunger and the frangible portion achieved by weakening the shaft of the plunger at the connection to the piston so that it breaks upon completion of the forward, delivery stroke of the plunger. Alternatively, the one way connection can be disconnected as the plunger is 10 withdrawn from the syringe. The frangible portion is configured to achieve foreshortening of the plunger shaft when the residual proximal portion of the plunger shaft is re-inserted into the piston bore. Thus, it is preferred that the shaft of the plunger be partially cut way at the frangible portion, for example by cutting transverse circular or other shaped portions out of the plunger shaft. When the frangible portion is broken, crenellated, cusped or other co-operating shaped ends to the two residual parts of the shaft are formed. When one part is rotated relative to the other, the crowns of one part are brought into register with the troughs of the other so that S. the plunger shaft foreshortens axially.

The axial bore within the plunger shaft which is to receive the 15 needle can extend from the proximal end of the plunger, ie.

that end which the user presses upon to depress the plunger, or can extend from the end face exposed when the one use connection is broken, ie. the distal end. It is preferred that the proximal end of the plunger be formed with a radiall.

20 extending shoulder to provide a thrust head upon which a user presses to depress the plunger within the piston bore of the syringe. It is also preferred that this shoulder be provided with a radial slot in register with the axial needle entry pr; in the wall of the plunger so as to assist location of tne needle with the axial entry port.

As indicated above, it is preferred that the syringe body is provided with locking means whereby the broken off proximal portion of the plunger can be pushed fully home into the bore ot the syringe due to its axial foreshortening and locked within the bore so that it can not subsequently be removed in an attempt to reconstruct the syringe.

The syringe of the invention can readily be manufactured by simple modification of the plunger as used in a conventional syringe so as to provide the one use connection and the bore in the plunger to receive the needle. Thus, the syringe body will RAo T00 11 typically be made from a plastic moulding having the needle extending axially therefrom and secured to the syringe body by a detachable or breakable mounting.

DESCRIPTION OF THE DRAWINGS: To aid understanding of the invention, it will now be described by way of illustration only with respect to preferred forms thereof as shown in the accompanying drawings in which Figure 1 is a diagrammnatic perspective view of the plunger and piston for use in the syringe; Figure 2 is an axial cross-sectional view through a syringe incorpqorating the plunger and piston of **Figure 1 (not shown in section) at the end of the delivery :stroke of the piston; Figure 3 is an axial cross-sectional view of the syringe and plunger of Figure 2 in its disabled form, with the needle demounted and housed within the plunger which has been axially foreshortened and re-inserted into the piston bore after use; Figure 4 shows in diagrammatic side views five stages in the operation of the syringe of Figures 2 and 3; Figure 5 shows in axial cross-section the operation of a preferred form of needle removal mechanism at the proximal end of the needle receiving member; and Figure 6 shows in diagrammatic axial cross-secticn an alternative form of the mechanism for locking the foreshortened plunger within the piston bore.

DESCRIPTION OF THE PREFERRED EMBODIMENTS: The syringe shown in Figures 2, 3 and 4 comprises a generally cylindrical tubular body 1 having a radial shoulder or finger grip projections 2 at the open, proximal, end thereof and 4n axial1 piston bore extending trom the open end- The other, distal, end of the piston bore is closed by a transverse end wall 3 having an ax.ial outlet spigot 4 upon which is mounted a hypodermic needle As shown in Figure 5, the needle can be mounted as a push fit 12 upon spigot 4 by means, of a needle mounting 6. Alternatively, the needle can be moulded into the spigot 4 during manufacture of the syringe. in this latter case, the spigot 4 or the needle mounting can be formed with a circumferential score or groove to provide a ring of weakness at which the needle 5 can be broken away from the syringe.

Within the piston bore of the syringe body is slideably journalled a piston 10 which is driven axially by a plunger 11 which, in normal -use, extends beyond the open end of the syringe body 1 to provide a radially enlarged thrust head 12 against which a user pushes to move the piston axially within the piston bore.

The plunger shaft also acts as the receptacle for the needle when it is detached from the syringe body. Thus, the plunger shaft 11 has an axial bore 20 therein which is adapted to act as the needle receiving chamber. The plunger shaft 11 can be :solid with the bore 20 formed axially therein, but is 20 preferably hollow as shown with an axial needle entry port in the side wall thereof which communicates with the -central axial bore The entry port 30 feeds the needle radially into the axial bore 20 within the shaft 11 and the radially outward lips of the entry port can be belied to assist location of the needle into the port 30. The bore 20 can extend axially from the distal or proximal end faces of plunger shaft 11 and the radially projecting thrust head 12 can have a radial slot 13 formed therein in register with the proximal end of port 30 to aid correct location of the needle 5 with respect to the entry port when the plunger is used to remove and house the needle 5 as described below.

Where the needle 5 is to be separated from the syringe by snapping the needle mounting 5 or spigot 4 at the line of weakness introduced by the circumferential groove in the needle mounting, as shown in steps 3 and 4 of Figure 4, it is preferred to form the bore 20 as a close fit upon the needle so that the needle is held firmly within the bore. It is also preferred to form the proximal end of the bore with a sharp rim or lip 21 about which the mounting or spigot flexes so as to assist breaking of the mounting or spigot at the desired point.

Where the needle 5 is mounted as a push fit upon the spigot 4 and is to be lifted off the spigot as the needle receptacle is moved transversely, the proximal end of the plunger bore 20 is provided with at least one transverse ramp member 22 as shown in Figure 5. Preferably, a second ramp member 23 is provided axially further into the bore 20 to trap the circumferential S: 15 bead 24, usually present at the proximal end of a conventional needle mounting 6, between the opposed faces of the two ramps 22 and 23. The two ramps are each cut with a radial slot and 26 which are a close fit upon the axial portions of the spigot 4 and the needle mounting 6 respectively so that the 20 upper, distal, face of the proximal ramp 22 bears against the underside, proximal face, of the mounting 6 and the distal ramp 23 guides and retains the mounting 6. As shown in Figure 5, progressive transverse engagement of the syringe and needle with the ramps 22 and 23 as the needle 5 is inserted transversely into the axial port 30 lifts the needle 5 and its mounting 6 axially off the spigot 4 to detach the needle from the syringe. The angle of the ramps 22 and 23 can be selected in known manner from a knowledge of the geometry of the spigot and the mounting 6 to achieve the required extent of the axial movement to separate the needle from the syringe.

It is preferred that the proximal end of the plunger shaft 11 carry an external circumferential groove 40 or a circumferential rib 41 which will engage with a circumferential rib 42 at the lip of the open end of the piston bore to retain the foreshortened piston shaft within the piston bore as described below.

14 The shaft of the plunger is formed so that the shaft can be broken to disable the plunger. This also allows at least part of the plunger to be removed from the piston bore and presented to the needle so that the needle can be inserted into the chamber 20 within the shaft of the plunger via the entry port The shiaft and needle are then preferably re-inserted into the piston bore in the syringe body with the shaft of the plunger axially foreshortened, the engagement of the groove with, and/or the snap passage of rib 41. past, rib 42 serving to retain the foreshortened plunger within the piston bore to inhibit any attempt to re-assemble the syringe for subsequent re-use. The plunger 11 is provided at or adjacent the piston ie. at its distal end, with a one time use frangible connection 14, for example one which is broken when the piston butts against the end wall 3 and pressure is applied to the connection as the user attempts to depress thrust head 12 further. However, a particularly preferred form of one use 'connection is provided by means of a series of radial bores, apertures or cut outs 15 through the plunger shaft 12. adjacent 20 the piston 10, which remove a substantial portion of the material of the shaft at this point. This forms a weak point at which the shaft 11 can be broken by flexing the shaft.

*0*Where the plunger shaft is solid, the piston end of the plunger shaft can be formed with an axial recess so that the wall.

thickness of the shaft is reduced at this enid, and the transverse bores or cut outs 15 are formed in this thinner wall area of the shaft.

The cut outs 15 are conf igured so that they will allow the broken ends of the plunger shaft to nest upon one another and thus achieve a degree of axial foreshortening of the plunger shaft. Thus, the cut outs' can be circular or ovals, triangles, rectangles or other axially elongated shapes which provide a narrow remainder to the plunger wall between adjacent cut outs.

When the plunger shaft is broken, the break will occur at these narrow remainders to give a crenellated end to each of the sections 11a and l1b of the plunger shaft. The crenellations is on one end can be moved out of register with those on the other end by relative rotation of the two ends about the longitudinal axis of the plunger sections so that the raised portions or crowns of one crenellated ehd will nest in the troughs of the other crenellated end to achieve the axial foreshortening of the plunger shaft.

Preferably, the plunger shaft 11 is provided with one or more radial projections 16 on the shaft portion 11 b which is located distally of the one use connectCion 14. These are to engage the radial rib 42 described above to prevent the whole of the plunger being withdrawn f rom the piston bore. The engagement of the ribs 42 and 16 also serves to locate the weak~ point in the shaft approximately in register with the rim of 15 the open end of the piston bore which can then act as the fulcrum about which the plunger shaft is flexed to break the shaft.

For use, the syringe is assembled by mounting the needle 5 upon 20 the syringe body and inserting the plunger 11 and piston into the piston bore in the syringe body step 1 in F'igure 4.

Apart from the cut outs 14, the bore 20 and the axial needle entry port 30 in the plunger shaft 11, the needle, its mounting and the remainder of the syringe can be of conventional design and construction.

In use, the piston 11 is withdrawn in the piston bore to suck medicament or other fluid into the piston bore in the conventional manner. The fluid is injected in the conventional manner by depressing the thrust head 12 to drive the piston axially. After use, the plunger shaft 11 is withdrawn until the projections 16 on the shaft 11 engage the rib 42 at the lip of the piston bore. The shaft is then flexed laterally to cause it to break at the ring of weakness introduced by the cut outs 14 step 2- in Figure 4.

The proximal section 11a of the shaft 11 is then applied 16 transversely to the needle end of the syringe so that the needle 5 is inserted transversely into the bore 20 step 3 in Figure 4. Where the needle is to be broken of f the syringe body, the plunger section Ila is flexed as shown in step 3 of Figure 4 about the longitudinal axis of the needle to break the spigot 4 or the needle mounting 6 as shown in step 4 of Figure 4 to leave the needle 5 and the residue of the mounting or spigot held in the bore 20 of the shaf t section as shown in Figure 3.

With the alternative form of construction shown in Figure V...'the ramp 23 engages the underside of the needle mounting 6 and moves the mounting 6 axially with respect to the spigot 4 as the needle is inserted transversely into the axial slot Where the second ramp 23 is present, this can trap the mounting 0: against the upper face of ramp 22 and thus retain the needle and its mounting securely within the bore :The shaft section Ila carrying needle 5 in bore 20 is then re- 20 inserted into the piston bore of the syringe body 1. By aligning the crenellated ends of the two sections la.and 11b with one another as described above, the axially projecting portions are out of alignment with one another, and the axial length of the plunger shaft 11 can be reduced to allow the plunger to be inserted far enough axially into the piston bore to allow rib 42 at the lip of the piston bore to engage in the groove 40 in the plunger shaft and thus lock the shaft within the piston bore step 5 in Figure 4 and as shown in Figure 3.

In the alternative form of construction shown in Figure 6, the proximal end of the plunger is formed with two or more sharp radial teeth 50. When the remnant Ila of the plunger shaft carrying the needle in the axial bore 20 is inserted into the piston bore, lateral pressure on the thrust head 12 flexes the end of the plunger shaft and allows teeth 50 to retract radially and thus fit into the proximal end of the piston bore.

When the lateral pressure is released, the end of the plunger 17 shaft expands radially causing the teeth 50 to bite into the wall of the piston bore and thus lock the plunger shaft within the bore. Alternatively, the teeth 50 may not be retracted and the plunger forced axially into the piston bore to engage the teeth 50 with the inner face of the piston bore.

Using the features of the invention, the syringe provides its own needle breaker and receptacle means, which aids the safe disposal of the needle and syringe, as well as rendering the syringe inoperative by breaking the plunger shaft.

e *0 a S s0 0 0 0* *00

Claims

2. A syringe as claimed in claim 1, characterised in that the frangible connection is configured so that relative rotation of the residual portions of the disabled connection about their 19 common longitudinal axis allows the opposing faces of the broken frangible section to nest within one another whereby the plunger can be foreshortened axially.
3. A syringe as claimed in either of claims 3 or 2, characterised in that the plunger member incorporates means for separating the needle from the syringe body.
4. A syringe as claimed in ulaim 3, characterised in that the means for separating the needle from the syringe body is adapted to move the needle axially with respect to the syringe :...body as the needle is inserted transversely into the needle receiving chamber in the plunger member so as to separate the I"needle from the syringe body.
5. A syringe as claimed in claim 4, characterised in that one of the needle mounting or the axial bore in the plunger member is provided with one or more radial projections or recesses and the other is provided with one or more ramp members adapted to 20 engage with the radial projections so that the needle is moved axially off the syringe body when the needle is introduced into the needle receiving chamber in the plunger member.
6. A syringe as claimed in any one of the preceding claims, characterised in that the plunger is formed with the frangible connection at or adjacent the distal end thereof, and the axial bore is provided in the proximal portion of the plunger, whereby the proximal portion of the plunger shaft can be separated from the body of the syringe and the needle inserted transversely into the axial bore in the proximal portion of the plunger shaft via the axial aperture.
7. A syringe as claimed in any one of the preceding claims, characterised in that locking means are provided between the plunger member and the syringe body whereby the residue of the plunger shaft after separation of the frangible connection can be retained within the piston bore. 20
8. A syringe as claimed in claim 7, characterised in that at least one of the plunger member and/or the wall of the piston bore is provided with means for engaging the other so as to retain the plunger within the piston bore in the axially fore- shortened position.
9. A syringe as claimed in any one of the preceding claims, characterised in that the axial needle entry aperture extends for at least 100% of the axial length of the needle which is to be housed in the axial bore in the plunger member. DATED this 4th day of April 1997 C: HARWILL INDUSTRIES (PTY) LIMITED S: and THOMAS IAN PETER DUMMETT By their Patent Attorneys CULLEN CO S