GB2321409A

GB2321409A - Cap for non-reusable syringe

Info

Publication number: GB2321409A
Application number: GB9805940A
Authority: GB
Inventors: Thomas Mcdonald Ford
Original assignee: Sovereign Surgical Ltd
Current assignee: Sovereign Surgical Ltd
Priority date: 1994-01-25
Filing date: 1994-01-25
Publication date: 1998-07-29
Anticipated expiration: 2014-01-25
Also published as: GB9401309D0; GB9805940D0; GB2287192B; GB2321409B; GB2287192A

Abstract

The cap is for use with a syringe in which the needle is retractable into the barrel after use. The cap 5 engages with and fits over the end of the barrel 1 following retraction of the needle 2. A shielding means 7 projects from the engagement portion 6 of the cap, and is shaped to shield at least the outer penetrating end of the needle. The cap may engage the barrel by screw thread (see figures 5a-c) or friction fit (for example figures 6e-7b). The shielding means may comprise a conical projection which fits over part or all of the needle, or a tapering projection made of a flexible or resilient material such as rubber (figure 6f) which is punctured by the needle tip.

Description

CAP FOR NON-REUSABLE SYRINGE The invention relates to a an end cap for a syringe.

It is well-known that when surgical syringes are disposed of they should be treated with great care and pass through disposal systems which are designed to avoid any possibility of contamination. Despite this fact, it is known that used syringes are a health hazard and individuals who come into contact with such syringes may suffer illness through being cut by same In addition, it is known that used syringes are typically used by groups of drug addicts thus increasing the possibility of contamination. More than ever, cross contamination is extremely dangerous because it is now a well established fact that infection by HIV is transmitted by the use of, or accidents with, syringes which have previously penetrated infected individuals. The risks associated with accidental needle stick injury are well appreciated by clinicians but it is often difficult to abide by guidelines for disposal of syringes in practice.

There is therefore a need to provide syringes which cannot be used on more than one individual and which are easy to handle and render safe.

To some extent, safety has been increased by providing a syringe of the sort shown in Figures 1 and 2. The syringe comprises a conventional barrel I which has attached at a first end a needle 2 and at a second end a plunger 3. The syringe can be used in a conventional fashion, excepting that when a clinician has finished with the syringe, the plunger can be attached to the needle and the needle can subsequently be withdrawn into the barrel. In the embodiment shown in Figures 1 and 2 the means of attachment is a simple lock and turn mechanism. Withdrawal of the needle into the barrel results in the needle no longer being exposed and therefore reduces the likelihood of an individual accidentally puncturing themselves with the needle. Occasionally, a plug or cap is provided to cover the needle end of the barrel to ensure the needle is shielded.

However, although the above arrangement goes some way to increasing the safety of medical syringes, it is not foolproof This is because firstly such plugs or caps are small and difficult to handle and secondly because it is not unknown for the end cap to come loose and leave the tip of a used needle relatively exposed.

Moreover, with this arrangement it is possible for an individual to re-use the syringe simply by using the plunger to push the needle to a fUrthermost end of the barrel and then using the simple lock and turn mechanism the needle and plunger can be disengaged so as to facilitate use of the existing syringe.

With the above disadvantages in mind it is an object of the invention to provide a cap for a syringe which more effectively overcomes the hazards associated with handling used syringes.

Accordingly, the present invention provides a cap for use in conjunction with a non-reusable syringe of the type comprising a barrel provided at a first end with a needle and at a second end a plunger adapted for axial movement within the barrel, the plunger including means for attaching the needle and the plunger to one another so that, after use, the needle can be withdrawn into the barrel, wherein the cap is adapted to fit the first end of the barrel after the needle has been withdrawn into the barrel, the cap having on its innermost side a shielding means projecting therefrom so as to reduce the incidence of needle stick injury.

Preferably, the shielding means projects into the barrel and surrounds at least the tip of the needle.

In a preferred embodiment of the invention the shielding means projects substantially into the body of the barrel so as to shield the entire length of the needle.

In one arrangement the shielding means comprises a resilient member which projects into the barrel along an axis aligned with the central longitudinal axis of the needle so that, when the cap is in position, the needle penetrates the resilient shielding means.

Alternatively, the shielding means surrounds at least the tip of the barrel.

The cap is profiled to fit over the free end of the plunger in a storage or transport mode prior to use.

The shielding means provides a push friction fit between the barrel and the cap to prevent liquid leaking from the barrel.

The cap is provided with a flat base for standing on a flat surface with its open mouth disposed upwardly so that, after use, when the needle has been withdrawn into the barrel, the barrel can be sealed by push fitting the first end of the barrel to the cap thereby reducing the incidence of needle stick injuries.

Preferably, the cap or the shielding means is profiled to guide the barrel into alignment with the cap to facilitate single handed operation.

The syringe includes a breakable plunger whereby upon withdrawal of the needle into the barrel, the section of the plunger extending beyond the confines of the barrel can be broken off for rendering the needle non-hinctional.

In a preferred embodiment of the invention the plunger is provided with lines of weakening which are disposed adjacent but beyond the confines of the barrel when the plunger is retracted to a position where the needle is withdrawn into the barrel.

In an alternative aspect of the invention, the syringe is of the type including: a barrel; and a plunger comprising a tube means provided at a first end with a needle and at a second end with dialysis apparatus or the like, the plunger being adapted for axial movement within the barrel so that, after use, the needle can be withdrawn into the barrel , the cap being adapted to fit on the first end of the barrel, the cap having, on its innermost side, a shielding means which projects from the end cap whereby at least the tip of the needle is shielded by the shielding means.

The above aspects of the invention ensure that once a syringe has been used and the needle associated with same has been retracted into the barrel of the syringe then the means external of the barrel for manipulating the needle, ie the exposed plunger, is no longer available for use. The specialised barrel cap provides a second safety means which ensures that the tip of a used and withdrawn needle is shielded.

In the above described embodiments of the invention any suitable means may be provided for retracting the needle within the barrel after use.

Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings wherein; Figure 3 represents a plan view of a syringe adapted in accordance with the invention; Figures 4a, 4b and 4c represent a first cap in accordance with the invention; Figures Sa, 5b and Sc represent a second cap in accordance with the invention; Figures 6a, 6b, 6c, 6d, 6e and 6f represent a third cap in accordance with the invention; Figures 7a and 7b represent a fourth cap in accordance with the invention; Figures 8a and 8b represent a fifth cap in accordance with the invention; Figure 9 represents a sixth cap in accordance with the invention; Figure 10 represents a seventh cap in accordance with the invention; and Figures ii a, II b and 11 c represent an eighth cap in accordance with the invention.

Referring to the Figures and firstly to Figure 3, there is shown a syringe for use in medical applications comprising a barrel 1, a needle 2 which is adapted to slidably move within barrel 1 and a plunger 3 which is also adapted to move within barrel 1. Furthermore, as previously mentioned, needle 2 and plunger 3 are provided with any form of suitable attachment means whereby needle 2 and barrel 3 can be linked together so that when the syringe has been used needle 2 can be withdrawn into the main body of barrel 1 using plunger 3. When this has been completed, to a substantial extent, the tip of needle 2 is relatively shielded by the barrel 1.

However, it can be seen that it is possible to extend needle 2 with respect to barrel 1 by reinserting plunger 3 into barrel 1. Tt is therefore possible to re-use the syringe by following extension of needle 2 with uncoupling of needle 2 and plunger 3. To prevent this happening, plunger 3 is provided with lines of weakening 4 which enables a user to break off the exposed end 3a of plunger 3 thus leaving only a short fraction 3b of plunger 3 remaining inside barrel 1. It follows that when this action is complete it is no longer possible to uncouple needle 2 and plunger 3 and what is more it is extremely difficulty to extend needle 2 with respect to barrel 1.

The positioning of lines of weakening 4 along the length of plunger 3 is largely determined by the amount of plunger 3 extending beyond barrel 1 when needle 2 is withdrawn into barrel 1. It is advantageous to ensure that lines of weakening 4 are provided on plunger 3 as near as possible to the end of barrel 1 in which the plunger is located. in preferred embodiments of the invention markings or guides may be provided so as to guide a user thus ensuring that needle 2 is withdrawn into barrel 1 by a predetermined amount prior to the breaking off plunger 3. For example, an indicator may be provided on barrel I so that a user can ensure that a preselected point of needle 2 is aligned with the indicator before the extended portion of plunger 3 is broken off In addition to the above aspect of the invention there is also provided a second safety measure comprising a cap which is adapted to fit on needle end A of barrel 1 after a needle has been retracted within said barrel The cap is adapted not only to seal the exposed end A of the barrel but also to shield the tip of needle 2 within barrel 1.

Examples of various embodiments of the cap according to the invention will now be described.

Referring firstly to Figures 4a 4b and 4c there is shown in Figure 4a a needle 2 which has been withdrawn into barrel 1 of a syringe so that the tip of needle 2 is relatively shielded by barrel 1. Furthermore, the exposed end of plunger 3 has been broken off so that this syringe cannot be used. In Figure 4b there is shown a cap for use with the syringe illustrated in Figure 4a. The cap comprises a circular seal 5 having an annular rim 6 depending therefrom. In addition, on the innermost side of the cap there is provided a centrally mounted conical shielding means 7 which also depends from the cap 5 such that the widest portion of means 7 is furthest from the cap 5. The size and shape of means 7 is adapted to fit over needle 2. Thus when the cap shown in Figure 4b is placed on the syringe shown in Figure 4a the configuration shown in Figure 4c is achieved whereby rim 6 overlies the upper outermost edges of barrel I and means 7 overlies needle 2 located within barrel 1. In this arrangement necdle 2 is shielded such that if cap 5 is loosened or removed, the tip of needle 2 is not exposed.

Referring now to Figures Sa, Sb and 5e there is shown an alternative cap in accordance with the invention. As shown in Figure 5a the uppermost outermost edge of barrel 1 is provided with an annular seal 8. In addition, the cap shown in Figure Sb which is substantially similar to the cap described above with reference to Figure 4b is provided with a circular seal 5 and depending therefrom an annular rim 6 and a shielding means 7. In addition, the innermost edge of rim 6 is provided with a seal 9 adapted to frictionally mate with seal 8 provided on barrel shown in Figure 5a. Thus when the cap shown in Figure Sb is placed in mating engagement with the syringe shown in Figure 5a seals s and 9 engage so as to provide a tight fit and thus safeguard against cap 5 being removed from barrel 1.

This arrangement is shown in Figure Sc.

Tn an alternative embodiment of the invention seals 8 and 9 may be replaced by screw threaded arrangements such that the cap can be screwed onto the end of the syringe.

Referring now to Figures 6a, 6b, 6c. 6d, 6e and 6f there is shown yet an alternative embodiment of a cap in accordance with the invention.

Referring firstly to Figures 6a, 6b and 6c there is shown a needle 2 which has been withdrawn into barrel 1 using plunger 3. The extended end of plunger 3 has been broken off Needle 2 is provided with a conical shielding means 10 which is sized and shaped to fit over needle 2. In addition, there is provided a cap which comprises a circular seal 5 whose diameter is slightly greater than the diameter of barrel I. On the innermost side of seal 5 there is provided a conical tapering projection which is adapted so that the cap can be pushed onto barrel 1 to provide a friction fit, In Figures 6d 6e and 6f there is shown an alternative arrangement where a cap is provided with a circular seal 5 of slightly larger dimension than barrel 1 and on its innermost side a conical tapering projection. In this alternative embodiment the projection is either hollow (Figure 6e) or is made of a flexible or resilient material such as rubber (Figure 6f). Moreover, the projection is of such length that when the cap is positioned on the barrel the tip of needle 2 is made to either fit inside or puncture the projection according to the nature of same. In this way, needle 2 is used to hold the cap 5 in position.

Referring now to Figures 7a and 7b there is shown yet a further alternative embodiment of the invention comprising a cap having an outermost circular seal 5 and on the innermost side of seal 5 there is provided a conical tapered projection 5b. Moreover, attached to the outermost end of projection Sb is a cylindrical member 12. Member 12 is sized and shaped such that when the cap is positioned on barrel 1, needle 2 is shielded by member 12. It is also of note that member 12 is spaced from the outermost end of the cap 5 by projection Sb so that it does not interfere with the sealing of the cap S against barrel 1.

Referring now to Figures 8a and 8b there is shown a yet alternative embodiment of the invention which comprises the provision of a cap having a circular seal 5 and depending therefrom an annular rim 6. Furthermore, on the innermost surface of seal 5 there is provided a hollow annular projection 13 which is sized and shaped so that projection 13 fits over the length of needle 2. Projection 13 is mounted on an inwardly tapering projection 5b attached to the innermost side of seal S so that the diameter of member 13 is less than that of seal 5. Thus when the cap is mounted on barrel I member 13 not only overlies needle 2 but it also is spaced from the innermost walls of barrel 1.

Referring now to Figure 9 there is shown yet an alternative cap which comprises seal 5 having depending therefrom an annular rim 6 defining a central aperture 14.

The diameter of aperture 14 is less than the diameter of barrel 1. Rim 6 is provided with an annular slot 15 which penetrates to a substantial depth, but not all of rim 6. The diameter of slot 5 is substantially equal to the diameter of barrel 1 such that the cap can be located on barrel 1 by positioning the upper outermost rim of barrel 1 within annular slot 15. Moreover, the diameter of recess 14 is such that it accommodates needle 2 when covered with a conventional needle guard 10.

Referring now to Figure 10 there is shown yet an alternative embodiment in accordance with the invention which comprises a solid tubular member 0 S provided on a first transverse edge with a centrally located circular recess 16 defined by annular rim 15a A similar circular recess is provided on the opposite transverse end excepting that this recess 17 is of a greater depth than recess 16 but of a smaller diameter than recess 16. The diameter of tube 15 is slightly less than the diameter of barrel 1 such that, in use, the member can be push-fittcd within the end of barrel 1 and recess 16 is adapted to accommodate guard 10 of needle 2.

Recess 17 is adapted to accommodate a projection means extending from the uppermost surface of a conventional push fit end cap. Thus tube 15 serves Rs an intermediary plug or cap holding needle 2 and a further cap. as described above, in position within barrel 1.

Referring now to Figures ila, 1 ib and 1 ic there is shown yet an alternative arrangement in which the syringe is adapted for use in conjunction with apparatus for controlling the flow of extra corporeal blood, ie dialysis, aphemisis and blood giving/donation. In this arrangement, a disposable plastic tubing 20 is provided at a first end with a needle 21 and at a second end with suitable dialysis apparatus or the like (not shown). Further, a barrel preferably comprising a plastic sheath 22 which is shaped and sized so as to fit over the needle end of tube 20 and further to provide clearance thereabout, is fitted to the end of tube 20 and held in place via attachment means such as deflectable sliders 23. After the syringe has been used needle 21 is withdrawn into sheath 22 by pulling tube 20 so that it slides rearwardly with respect to sheath 22 and over deflectors 23. When syringe 21 has been pulled sufficiently within sheath 22 a cap as described in any of the above embodiments is attached to the outermost end 22a of sheath 22. It is envisaged that the cap shown in Figure 6f would be suitable because it would ensure that the tip of the syringe needle 21 would be secured within a resilient member and so prevent blood loss from the system which, in the instance of this apparatus, would be much greater than leakage from a conventional syringe. The tube may subsequently be clamped and cut or torn from the encased needle 21.

Using any one of the caps in accordance with the invention, a needle which has been withdrawn into the barrel of a syringe can be shielded from a user so as to minimise the possibility of a user being cut or punctured by a used syringe.

Moreover the provision of a breakable plunger which can, in part, be detached ensures that once a needle has been withdrawn into a barrel of a syringe the needle cannot subsequently be re-used.

It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only and that various alterations and modifications are possible with the scope of the appended claims

Claims

CLAIMS 1 A cap for use in conjunction with a non-reusable syringe of the type comprising a barrel provided at a first end with a needle and at a second end a plunger adapted for axial movement within the barrel, the plunger including means for attaching the needle and plunger to one another so that, after use, the needle can be withdrawn into the barrel, wherein the cap is adapted to fit the first end of the barrel after the needle has been withdrawn into the barrel, the cap having on its innermost side a shielding means projecting therefrom so as to reduce the incidence of needle stick injury.
2. A cap according to Claim 1, in which the shielding means projects into the barrel and surrounds at least the tip of the needle
3. A cap according to Claim 2, in which the shielding means projects substantially into the body of the barrel so as to shield the entire length of the needle
4. A cap according to any one of the preceding claims, in which the shielding means comprises a resilient member which projects into the barrel along an axis aligned with the central longitudinal axis of the needle so that when the cap is in position the needle penetrates the resilient shielding means.
5 A cap according to Claim 1, in which the shielding means surrounds at least the tip of the barrel.
6. A cap according to any one of the preceding claims, in which the cap is profiled to fit over the free end of the plunger in a storage or transport mode prior to use.
1. A cap according to any one of the preceding claims, in which the shielding means provides a push friction fit between the barrel and the cap to prevent liquid leaking from the barrel.
8. A cap according to any one of the preceding claims, in which the cap is provided with a flat base for standing on a flat surface with its open mouth disposed upwardly so that, after use, when the needle has been withdrawn into the barrel, the barrel can be sealed by push fitting the first end of the barrel to the cap thereby reducing the incidence of needle stick injury.
9. A cap for use in conjunction with a non-reusable syringe of the type including: a barrel; and a plunger comprising a tube means provided at a first end with a needle and at a second end with a dialysis apparatus or the like, the plunger being adapted for axial movement within the barrel so that, after use, the needle can be withdrawn into the barrel. wherein the cap comprises an engagement element having an innermost side which is adapted to engage the first end of the barrel, the engagement element including a shielding means projecting from the innermost side, the shielding means being operable to prevent ready access to the needle, so as to reduce the incidence of needle stick injury
10. A cap for use in conjunction with a non-reusable syringe substantially as herein described with reference to and as shown in Figures 4b, 4c, 5b, 5c, 6b, 6c, 6e, 6f and 7a to I lc of the accompanying drawings

9. A cap according to Claim 8, in which the cap or the shielding means is profiled to guide the barrel into alignment with the cap to facilitate single handed operation.

10. A cap according to any one of the preceding claims, in which the syringe includes a breakable plunger whereby upon withdrawal of the needle into the barrel, the section of the plunger extending beyond the confines of the barrel can be broken off for rendering the needle non-functional.

11 A cap according to Claim 10. in which the plunger is provided with lines of weakening which are disposed adjacent but beyond the confines of the barrel when the plunger is retracted into a position where the needle is withdrawn into the barrel.

12. A cap according to any one of the preceding claims, in which the syringe is of the type including: a barrel; and a plunger comprising a tube means provided at a first end with a needle and at a second end with a dialysis apparatus or the like, the plunger being adapted for axial movement within the barrel so that, after use, the needle can be withdrawn into the barrel, the cap being adapted to fit on the first end of the barrel, the cap having, on its innermost side, a shielding means which projects from the cap whereby at least the tip of the needle is shielded by the shielding means.

13. A cap for use in conjunction with a non-reusable syringe substantially as herein described with reference to and as shown in the accompanying drawings.

Amendments to the claims have been filed as follows CLAINIS 1. A cap for use in conjunction with a non-reusable syringe of the type comprising a barrel provided at a first end with a needle and at a second end a plunger adapted for axial movement within the barrel, the plunger including means for attaching the needle and plunger to one another so that, after use, the needle can be withdrawn into the barrel, wherein the cap comprises an engagement element having an innermost side which is adapted to engage the first end of a syringe barrel after the needle has been withdrawn into the barrel, the engagement element including a shielding means projecting from the innermost side, the shielding means being operable to prevent ready access to the needle, so as to reduce the incidence of needle stick injury.

2. A cap according to Claim 1, in which the shielding means projects into the barrel in use and surrounds at least the tip of the needle.

3 A cap according to Claim 2, in which the shielding means projects substantially into the body of the barrel so as to shield the entire length of the needle.

4. A cap according to any one of the preceding claims, in which the shielding means comprises a resilient member which projects into the barrel along an axis aligned with the central longitudinal axis of the needle so that when the cap is in position the needle penetrates the resilient shielding means.

5. A cap according to Claim 1, in which the shielding means surrounds at least the tip of the barrel.

6 A cap according to any one of the preceding claims. in which the shielding means provides a push friction fit between the barrel and the cap to prevent liquid leaking from the barrel 7. A cap according to any one of the preceding claims, in which the engagement element of the cap is provided with a flat base on its outermost side for standing on a flat surface with its open mouth disposed upwardly so that, after use, when the needle has been withdrawn into the barrel, the barrel can be sealed by push fitting the first end of the barrel to the cap thereby reducing the incidence of needle stick injury.

S. A cap according to Claim 7, in which the cap or the shielding means is profiled to guide the barrel into alignment with the cap to facilitate single handed operation.