GB2414939A

GB2414939A - Hypodermic syringe

Info

Publication number: GB2414939A
Application number: GB0413020A
Authority: GB
Inventors: Amer Shaikh
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-06-11
Filing date: 2004-06-11
Publication date: 2005-12-14
Also published as: GB0413020D0

Abstract

The stem 13 which operates the plunger 14 of a hypodermic syringe is hollow and joins the plunger at a point of weakness. After use in an injection the stem 13 is broken off and the needle 17 is inserted into the blind bore of the stem 13 to sheath it. In a preferred embodiment the needle 17 is retractable into the barrel 11 of the syringe and the hollow stem 13 is insertable into the barrel 11 from the needle end so that when sheathed by the stem 13 the needle is also sheathed by the barrel 11 and both ends of the barrel are closed.

Description

24 1 4939 "HYPODERMIC SYRINGE" This invention relates to an improved

hypodermic syringe, and more particularly to a hypodermic syringe which provides for improved used needle disposal.

The safe disposal of used hypodermic needles is a serious problem. livery year numerous medical staff fall victim to accidental in jCCtiOT1 by what may be badly infected used needles.

A principal object of the present invention is to address this problem.

0 In accordance with the present invention there is provided a hypodermic syringe comprising a plunger moveable in an elongated barrel by a stem which projects through one end of the barrel, wherein the stem is hollow and has a point of weakness near to the plunger, the arrangement being such that after withdrawhg the plunger to said one end of the barrel the stern can be broken off to provide it with an open end and a needle mounted at the other end of the barrel can theta be inserted in the stem, the blind bore of the stem being of length sufficient fully to receive the needle.

I f the needle is now dismounted from the barrel it will be almost completely enclosecl. This arrangement may be regarded as an alternative to presently available retractable needles, in which after use a needle can be retracted into the baTTel of the syringe.

Preferably, however the hollow stem of the present invention is combined with a retractable needle assembly. In a prct'erred embedment of the invention a needle support element is provided at the other end of the barrel, the plunger and the needle support element having coupling means such that by moving the plunger to said other end of the barrel the plunger and needle support element can be coupled and thereafter by withdrawing the plunger by means of the stem the needle can be retracted within the barrel jointly with the needle support clement, tle arrangement being such blat after the needle is fully received into the barrel the stem can be broken of the plunger at the area of weakness to provide the stern with an open end, alter which the open end of the stem can be passed over the needle point and the stem inserted into the barrel until a finger plate at tile end of the stem remote from the plunger closes said other end of the barrel.

By this arrangement the used needle is double-sheatlled first by the hollow stem and then by the barrel itself. If all components are made fi om a material which the needle cannot penetrate it will be sai'ely encapsulated. A so-called "sharps sal'e" box or bin for used hypodermics whicl1 is currently to be found In surgeries and hospitals can be dspensecl with and it will be unnecessary to handle the used needle at all.

lo Preferably a formation on the stem near to the finecr plate will engage with a formation at said other end oi'tlle barrel when the latter is closed by the tinger plate to lock the steno in position.

A t'onnation in the barrel near to said one end thereof may be adapted to engage behind the plunger when the latter is fully wtbdrawn thereby to lock the plunger in a position closing said one end of the barrel.

Each said Connation may be a deformable latch whicl1 will allow movement past it in one direction but not in the other.

the said coupling means may comprise a male formation on one of the plunger or needle support element which will snap-engage Fitly a female formation ol'the other ofthe plunger or needle support element when the plunger is moved fully to said one other end of the barrel thereby nonreleasably to lock tile plunger and needle support element together.

A prefaced embodiment of the invention will now be described by way of non-lirmitative example with reference to the accompanying clrawings, in which: Figure I is a sectional elevation of a hypodermic syringe in accordance with the present invention in its in-use condition, and [Figure 2 is a similar view of the syringe of Figure I in its condition encapsulating a used needle.

The hypodermic syringe 10 illustrated comprises an elongated barrel] I which may be moulded Tom a transparent plastics material. I'ro jecting from an opening at one end of the barrel is a needle support element 12. This may engage a needle by means of a Luer lock or by a screw-threadecl connection. Through an opening at the other end of the barrel extends a stem 13 connected within the barrel to a plunger 14 and having at its end outside the barrel a finger plate 15. Said other end of the barrel is flared as at 16 to provide a grip lo for two fingers while the thumb is pressing the finger plate l S to move the plunger 14 toward tle needle support element 12, as occurs when an injection is being administered.

A nee-ile 17 (shown broken away in Figure I) has a mounting end 18 whicl1 releasably engages a tubular projection 19 of the needle support element 12. It may simply be a friction fit or there may be a screw-threaded engagement between the mounting end 18 of l 5 the needle and the tubular projection 19.

On the side of the plunger 14 remote from the stem 13 is a male projection 20. There is a correspondingly-shaped l-ermale Connation 21 in the needle support element 12. By this arrangement when the plunger 14 is moved fully into contact with the needle support element 12 (which occurs alter an injection has been administered) the projection 20 will enter and snap-engage with the female Connation 2l, locking the needle support element to the plunger. The needle support element 12 is held in position in the associated end of the barrel 11 by an adhesive or by breakable tabs (not shown). This connection can be broken by manipulation of the stem 13, alter which the needle support element] 2 can be moved by the plunger 14 toward the opposite end of the barrel 1 l. When the plunger 14 has been withdrawn by pulling the stem 13 as for out of the barrel 1 1 as it will go the needle 17 is carried inside the ban el as shown hi Figure 2. In this final position of the plunger 14 it passes beyond a latch 22 which will prevent a return movement of the plunger 14 such as would re- expose the needle 17. I he latch 22 and the similarly shaped latch on the male projection 20 are of a defonnable plastics material and are shaped so as to allow movement past them in one direction but not in the other.

In accordance with the present invention the stem 13 is hollow and an area 23 of weakness s is provided where it is joined to tile plunger 14. 'I'his area of weakness 23 will be outside the barrel when the stem 13 is fully withdrawn, permitting a user to break the stem 13 off the plunger 14 by defecting it angularly. When broken off the plunger 14 the stem 13 has a long blintl bore with an open end remote from the finger plate 15.

0 The user takes tile stem 13 to the end of the barrel I I from which the needle support element 12 has been removal and inserts the sten1 13 mto the barrel so that the needle 17 enters the open end of the bore in the stem and becomes fully received into the stem.

In1nediately before the finger plate 15 cones Into contact with the end of the barrel 11 from which the needle support 12 has been removed a latch 24 on the stem 13 near to the finger plate 15 engages behind the opening in that end of the barrel to prevent movement of the stem 13 back out of the barrel. Both ends of the barrel I I are thus closed and it is not possible to re-expose the needle, which is cioubly sheathed first by the stem 13 and secondly by the barrel 11.

In a modification of this embodiment of the invention the male and female components 20 and 21 whicl1 provide for a snap-engagement between the plunger 14 and the needle support 12 are replaced by a screw-threacted projection (not sllown) on the plunger whicl1 can be screwed into a screw-threadecl bore (not shown) in tile needle support when the plunger 14 is brought into contact with the neecIle support 12 and then rotated by means of the finger 2s plate 15. Tl1is screw-threaded coupling obviates any danger that the plunger 14 and needle support 12 may be accidentally coupled prior to use of the hypodermic, e.g. when filling it.

A principal advantage of these embodiments of the invention, in which the used needle is fully enclosed in a clouble-slleatlled housing Is that the syringe can be disposed of In nonnal waste and does not require the use of a special "sharps box".

The invcnton has so far been described as applied to a hypodermic syingc with a retractable needle. I-lowever in a simpler forth the invention provides, by the hollow stem ] 3, a sheath for a non-retractable needle. In this embodiment alter fully withdrawing the plunger 14 and exposing the area of weakness 23 of the stem the stem would be broken off the plunger 14, as bcf'ore, but then inserted over a needle still projecting fiom the barrel 11.

The needle would be removed from the barrel 11 only alter being fully received into the stem 13, the needle mounting formation 18 serving to close the open end of the blind bore in the stem 13.

All components of the syringe may be moulded from suitable plastics materials but the plunger 14 will be of natural or synthetic r ubbcr. The syringe of the invention is preferably, but not necessarily, a one-use, disposable item.

Claims

CLAIMS: I. A hypodermic syringe comprising a plunger moveab]e in an

elongated barrel by a stem wlicl' projects through one end ol' the barrel, wherein the stem is hollow and has a s point ol'weakness near to the plunger, the arrangement being such that after withdrawing the plunger to said one end ol'the barrel the stem can be broken off to provide it with an open end and a needle recounted at the other end of the barrel can then be inserted in the stem, the blind bore of the stem being ol'length sufl'iciellt frilly to receive the needle.
2. A hypoclernic syringe as claimed in claim l anti comprising a needle support element at the other end of the barrel, the plunger and the needle supl10rt clement having coupling means such that by moving the plunger to said other end ol' the barrel the plunger and needle support element earl be coupled and thereafter by withdrawing the plunger by means of the stem the needle can be retracted withal the barrel jointly with the needle support element, the arrangement being such that after the needle IS fully received into the barrel the stem can be broken off the plullgel at tile area of weakness to provide the StCl1 with an -'pen end, after whiel1 the open end of tile stein can be passed over the needle point and the steno Inserted into the barrel until a linger plate at the end of'tlle stem remote from the plunger closes said other end of the barrel.
3. A hyl10dermic syringe as claimed in claim 2, wherein a formation on the stem near to the finger plate will engage with a formation at said other end of the barrel when tile latter is closed by the finger plate to lock the stem in position.

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4. A hypodermic syringe as claimed ills claim 2 or claim 3, wherein a formation h1 the barrel near to said one end thereof is adapted k' engage behind the plunger when the latter is fillly withdrawn thereby to lock the plunger in a position closing said one end of the banel.
5. A hypodermic syringe as claimed in claim 3 or claim 4, wherein each said formation is a deformable latch which will allow movement past it in one direction but not in the other.

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6. A hypodermic syringe as claimed in any one of claims 2 - 5, wherein said coupling means comprises a male tonnation on one of the plunger or needle support element which will snap-engage with a female formation of talc other of the plunger or needle support element when tile plunger is moved fully to said one other end of the barrel thereby non- releasably to lock the plunger and needle support element together.
7. A hypodermic syringe substantially as hereinbefore described with reference to and as shown in the accompanying drawings. /