Title of Invention

A DISPOSABLE HYPODERMIC SYRINGE

Abstract

A disposable hypodermic syringe comprising a plunger and a barrel, the plunger being reciprocably accommodated in the barrel a first protrusion provided on the external periphery of the plunger, near its top, for butting, in the withdrawn state of the plunger, against a second protrusion provided on the internal periphery of the barrel, near its base, for preventing total withdrawal of the plunger from the barrel; a breakable stopper provided at the base of the plunger, located outside the barrel, for permitting the plunger, in its withdrawn state, to be pushed into the barrel, only after breaking the stopper; a flexible gasket engaging with the plunger near its top, characterised in that the top of the plunger has a head with a curved periphery, whereby the said head, in the fully pushed-in state of the plunger, rides over a ridge provided on the internal periphery of the nozzle of the barrel for locking therewith and thus immobilising the plunger.

Full Text

This invention relates to a disposable hypodermic syringe. The known disposable type hypodermic syringe is of the throwaway type, that is, a syringe which is to be thrown away after use, so that the same syringe is not used again for reasons of hygiene. However, in several cases, it is found that disposable hypodermic syringes are collected by the garbage man and sold to unscrupulous persons for being used again as new syringes. This is not only a health hazard, but a certain way of spreading diseases among the public. Accordingly this invention proposes a disposable hypodermic syringe which after use, camiot be reused thereafter. A disposable hypodermic syringe, according to this invention, comprises a plunger and a barrel, the plunger being reciprocably accommodated in the barrel; a first protrusion provided on the external periphery of the plunger, near its top, for butting, in the withdrawn state of the plunger, against a second protrusion provided on the internal periphery of the barrel, near its base, for preventing total withdrawal of the plunger from the barrel; a breakable stopper provided at the base of the plunger, located outside the barrel, for permitting the plunger, in its withdrawn state, to be pushed into the barrel, only after breaking the stopper; a flexible gasket engaging with the plunger near its top, characterised in that the top of the plunger has a head with a curved periphery, whereby the said head, in the fully pushed-in state of the plunger, rides over a ridge provided on the internal periphery of the nozzle of the barrel for locking therewith and thus immobilising the plunger. This invention will now be described with reference to the accompanying drawings which illustrate by way of example and not by way of limitation one of the various possible embodiments of the disposable hypodermic syringe proposed herein. Fig.l illustrating a view of the plunger P accommodated within the barrel B in its fiilly pushed-in state with the firusto-conical head H of the plunger locked with tiie ridge R on the nozzle N of the barrel B, to immobilize the plunger Fig. 2 illustrating a separate view of tiie gasket G Fig. 3 illustrating a separate view of the barrel B Fig.4 illustrating a separate view of the plunger P Fig. 5 illustrates a separate view of the plunger and gasket G Fig. 6 illustrates the stem S broken at the waist W after the plunger P is immobilised and an attempt is made to forcibly retract the plunger P into the barrel B The syringe has a plunger P reciprocably accommodated in a barrel B. The point where the needle (not illustrated) is fixed to the nozzle N is indicated byT. When the plunger P is withdrawn fi^om the barrel B for sucking the injectible into the barrel, first ring Dl provided on the external periphery of Top the plunger P, at its , butts against a second ring D2 provided on the internal periphery of the barrel, at its base, for preventing total withdrawal of the plunger from the barrel B. This arrangement prevents the injectible from spilling out of the barrel, when sucked into it. A breakable stopper J is provided at the base of the plimger, located otside the barrel. After manufacture of the syringe, the possibility of the user inadvertently pushing the plunger P into the barrel B and locking the plunger is eliminated. The user will therefore have to consciously break the stopper J, to enable the plunger to be operated. A flexible gasket G made of a material such as rubber engages with the plunger near its top. The top of the plunger has a head H with a curved periphery, such as, a frusto-conical periphery as illustrated. The head H, in its fiilly pushed-in state, rides over a ridge R, provided on the intemal periphery of the nozzle N of the barrel B, for immobilising the plunger P. Thus, when the injectible is fully pumped out of flie needle, by the plunger P, the head H is in its fully pushed-in state and extends beyond the ridge R, but cannot be retracted because the head H is now arrested by the said ridge to immobilize the plunger P The head H is mounted on a stem S fixed to the top of the plunger P. The stem has a waist W. This situation results in at least three advantages: (i) As stated above, the plunger P cannot be retracted into the barrel B after the head locks with the ridge R and this prevents re-use of the syringe, (ii) If the user or other person forces the plunger P to retract into the barrel, the stem S will break at the waist W, leaving the head H in the nozzle in its its locked position at the ridge, serving as a plug in the nozzle preventing any flow of the injectible in either direction in the nozzle, as illustrated in Fig. 6 (iii) Disposable reusable syringes are usually made of plastic. However, recycling the same, after use, poses problems because the gasket (made of rubber) remains inside die barrel after use and the plastic portion of the syringe cannot be recycled along with the gasket On the other hand in the case of the syringe proposed herein, after use, the plunger can be broken at the stem, leaving the plunger and gasket to be drawn out freely. In such event, after being drawn out, the gasket can be easily removed from the broken-away portion of (iv) the stem, leaving the plastic portions of die syringe to be taken away for recycling. It will be appreciated that fliis invention is not confined to the embodiment described and illustrated, but that various other embodiments are possible without departing from the scope and ambit thereof. I Claim: disposable hypodermic syringe comprising a plunger and a barrel, the plunger being reciprocably accommodated in the barrel; a first protrusion provided on the extemal periphery of the plunger, near its top, for butting, in the withdrawn state of the plunger, against a second protrusion provided on the internal periphery of the barrel, near its base, for preventing total withdrawal of the plunger from the barrel; a breakable stopper provided at the base of the plunger, located outside the barrel, for permitting the plunger, in its withdrawn state, to be pushed into the barrel, only after breaking the stopper; a flexible gasket engaging with the plunger near its top, characterised in that the top of the plunger has a head with a curved periphery, whereby the said head, in the fully pushed-in state of the plunger, rides over a ridge provided on the internal periphery of the nozzle of the barrel for locking therewith and thus immobilising the plunger. 2. A hypodermic syringe as claimed in Claim 1 wherein the first and second protrusions are first and second rings respectively. hypodermic syringe as claimed in any one of the preceding Claims wherein the periphery of the head is frusto-conical. A hypodermic syringe as claimed in any one of the preceding Claims wherein the head is mounted on a stem fixed to the top of the plunger, the said stem having a waist. 5. A disposable hypodermic syringe substantially as herein described with reference to and as illustrated in the accompanying drawings.

Documents:

1422-CHE-2004 AMENDED CLAIMS 26-06-2012.pdf

1422-CHE-2004 CORRESPONDENCE OTHERS 24-02-2012.pdf

1422-CHE-2004 CORRESPONDENCE OTHERS 26-06-2012.pdf

1422-che-2004-abstract.pdf

1422-che-2004-claims.pdf

1422-che-2004-correspondnece-others.pdf

1422-che-2004-correspondnece-po.pdf

1422-che-2004-description(complete).pdf

1422-che-2004-drawings.pdf

1422-che-2004-form 1.pdf

1422-che-2004-form 19.pdf

1422-che-2004-form 26.pdf