DEVICE FOR REMOVAL AND CONTAINMENT OF USED NEEDLES

Abstract: The present invention relates to a device for use in separating a capillary bore needle (5) from the body of an article (8) in which one end of the needle has been mounted for use of the needle, notably a one use disposable hypodermic syringe, which device is characterised in that it comprises a hollow body (1) having a capacity to contain a plurality of needles and configured so as to receive through an opening in a face of the body substantially the full length of the needle protruding from the article, the body having at or adjacent the said opening means, for example a foam plastic (3) optionally in combination with a membrane or collar over the needle entry opening, which are adapted to support and restrain the needle from lateral movement when inserted into the body and to provide a fulcrum about which the needle or its mounting in the article can be flexed so as to cause separation of the needle from the article, the body serving to contain the needle when it has been separated from the article.

Description: DEVICE FOR REMOVAL AND CONTAINMENT OF USED NEEDLES. The present invention relates to a device, notably to a device for breaking the needles from a hypodermic syringe. BACKGROUND TO THE INVENTION: Fine bore or capillary needles are often used as the operative end of a device to penetrate the skin of a person to inject or remove blood or other bodily fluids, for example lumbar fluids. When such needles have been used, they are usually contaminated with the blood or fluid of the person and for health reasons must be cleaned or sterilised before re-use. This is an increasingly expensive and time consuming operation and such needles and hypodermic syringes incorporating them have been put up in disposable form so that they are discarded after a single use. However, the disposal has to be in such a manner as to prevent unauthorised re-use of the syringe and such as to minimise the risk of someone contacting the discarded needle and becoming infected therefrom. To this end, it is current practice to cut the needles off hypodermic syringes after use so that the body of the syringe cannot be re-used and the needles can be disposed of separately. Typically, a hypodermic syringe needle is made from stainless steel capillary tubing which is both flexible and hard to cut. Therefore, present cutting tools require hardened or tool steel blades and this is expensive. Furthermore, cutting the needle off with such cutters often leaves a sharp projecting stump which can cause as much damage as the end of a conventional needle and may still carry contaminants which could infect; a cut made by the stump. Having cut the needle off the syringe, the user is still presented with the problem of disposal of the needle, which is now aggravated since the user now has to grip the needle itself and cannot use the body of the syringe to manoeuvre the needle. It has been proposed in UK Patent Specification No 2214082 A to provide the syringe with a hollow needle cover which can be flexed about the axis of the needle to snap the needle mounting off the syringe. However, if the needle cover is misplaced during use of the syringe, as may well occur, no other means are provided for rendering the syringe safe after use. Furthermore, since the cover is intended to be readily removed from the needle prior to use, it may not retain the needle firmly once the needle has been broken away from the syringe body. As a result, the needle may escape from the cover prior to disposal and present a double ended hazard to the user. We have now devised an improved method and device for breaking the needles away from a support, notably from a hypodermic syringe, which reduces the above problems. SUMMARY OF THE INVENTION Accordingly, the present invention provides a device for use in separating, eg. breaking, a capillary bore needle from an article on which one end of the needle has been mounted for use of the needle, which device comprises a hollow body having a capacity to contain a plurality of needles and configured so as to receive through an opening in a face of the body substantially the full length of the needle protruding from the article, the body having at or adjacent the said opening means which are adapted to support and restrain the needle from lateral movement when inserted into the body and to provide a fulcrum about which the needle or its mounting in the article can be flexed so as to cause separation of the needle from the article, the body serving to contain the needle when it has been separated from the article. Preferably, the body is also provided with means which is adapted to restrain the needle from free axial movement within the body during flexing of the needle. The invention also provides a method for separating a capillary bore needle from a supporting article at substantially the point at which the needle projects from the article, which method comprises inserting the distal end of the needle into the hollow body of a device of the invention and flexing the article transversely to the longitudinal axis of the needle whereby the needle is caused to separate from the article and be retained in the body. The invention can be applied to a wide range of forms of needle, for example f ne drawn glass irrigation canulae, lumbar puncture needles and other metal fine bore needles attached to syringes or tubing for use m drawing blood samples. However, the invention is of especial application in separating the stainless steel capillary bore needles from the bodies of disposable injection syringes. In such devices the needle is a sharp ended drawn stainless steel tube with an internal diameter of from 0.1 to 1.0 MIS. One end of the needle is imbedded into the body of the syringe during moulding of the plastic body of the syringe or otherwise substantially rigidly secured to the body of the syringe, for example by means of a push fit mounting. Typically, the needle projects from 1 to 7 cms from the free end of the syringe. For convenience, the invention will be described hereinafter in terms of breaking such capillary needles from a one time use plastic disposable syringe. The needle to be broken off is inserted into the hollow body through an opening in a wall of the body so that the needle is substantially completely contained with the body. The hollow body can be provided by a recess in an end of a cap used to protect the needle prior to its use, an axial bore in the body of the plunger used to operate the syringe, or the body of a container such as a tub or tube, preferably containing a suitable needle restraining medium as described below. The container can thus be a simple plastic open topped tub or the like and many different shapes and form of container " may be used. The container has a depth sufficient to receive the full length of the needle to be broken from the syringe body, typically 1.5 to 7.5 cms. The container has an internal capacity sufficient to hold a plurality of needles so that a single container can be used a number of times before it is necessary to dispose of the container and its load of needles. Typically, the container will be capable of holding from 10 to 100 needles. Preferably, the container has a removable top whereby the recess within the container can be exposed for use in breaking off the needle,* and the lid then re-applied to close the container and retain the needle securely within the container. The lid also protects a user from accidental contact with the needles within the container. The container is provided with a means which acts as the fulcrum about which the needle or its mounting is flexed so as to separate the needle from the syringe. This means can be provided by the lip of the opening in the wall of the container through which the needle is inserted into the container or a ridge or flange at or adjacent the lip of the opening. In this case, the lip of the opening, the ridge or flange is preferably formed with a sharp edge rather than a radiused edge. The needle can be a sliding fit through the opening in the container wall, which can be bell mouthed to aid insertion of the needle into the opening. However, it is preferred that the needle be a loose fit within the opening, as for example when the opening is provided by the open top of a plastics tub or the like. In this case it will be necessary to provide a means other than the lip of the opening which restrains the needle against lateral movement so that the needle or its mounting is caused to flex as the syringe is moved. This secondary means can be provided by a rubber, plastics or the like flange, rim or gripper around the lip of the opening and/or within the container body which reduces the freedom of lateral movement of the needle. Alternatively, a membrane can be mounted across the opening and/or within the container body so as to provide lateral restraint to the needle. Where a wide opening is used, a measure of lateral restraint may also be achieved by sub-dividing the interior of the container into two or more axial compartments, the axial walls of which provide a surface against which the side of the needle bears a is restrained against lateral movement. In a further alternative, the opening can be provided with an inwardly extending tube through which the needle passes and which provides the lateral restraint. The tube is for example from 0.5 to 2 cms long so that the needle is free to drop clear of the tube into the body of the container when it is separated from the body of the syringe. However, a particularly preferred form of lateral restraint for the needle is a foamed plastic or the like in-fill within the body of the container. I have found that this acts to restrain the shaft of the needle within the body of the container adequately to cause breakage of the needle when the syringe is swung about the axis of the needle. I believe that the use of such a foamed in-fill to provide the lateral restraint is novel and the invention therefore provides a device for use in breaking capillary bore needles away from the body of an article in which one end of the needle has been mounted for use of the needle, which device comprises a hollow body configured so as to receive through an opening in a wall of the body substantially the full length of the needle protruding from the article, the body containing a restraining medium adapted to receive the needle and to support the needle against lateral movement so as to provide a fulcrum at or adjacent the opening in the wall of the body about which the needle or its mounting in the article can be flexed so as to cause breaking of the needle or its mounting, the body serving to contain the needle when it has been broken away from the article. The restraining medium within the container can take a wide range of forms of material into which a needle can be inserted and which are sufficiently firm to prevent excessive lateral deflection of the needle within the container during the flexing of the needle to break it. Typically, the restraining medium is one which will prevent the needle from deflecting by more than 30° to either side of the longitudinal axis of the needle when first ins-erted into the medium. It is particularly preferred that the medium permit the needle to deflect by less than 10° to either side of the needle axis. The degree of deflection may also depend upon the position of the needle relative to the side wall of the container, since that wall will also serve to restrain the deflection of the needle. The optimal restraining material for use with a given needle and container can readily be determined by simple trial and error tests to determine whether the needle snaps within three to five flexings. Thus, suitable forms of restraining medium include closed or open pored foamed plastics having a sufficient degree of resilience, rolled paper or fabric, bundles of smaller bore tubes held within a larger diameter container, blocks of natural or synthetic rubber or other resins or polymers, blocks or pads of randomly orientated fibres, such as felted materials. Such materials are typical of those into which a needle can be driven axially and which will restrain the needle shank against excessive lateral deflection when the syringe body is flexed laterally about the axis of the needle. A particularly preferred restraining material for present use is a closed pore polyurethane or other synthetic polymer having a compressibility ratio, ie. the percentage reduction in volume of a 1 cm cube of the material when subjected to a load of 1kg per square cm, of from 5 to 25%. For convenience, the invention will be described hereinafter in terms of the use of such a foamed plastic restraining material. If desired, the overall pad of the restraining material may be formed from a series of cells of the material separated by rigid axial walls within the container, so as increase the effective compressibility ratio due to the presence of the adjacent wall. If desired, the restraining material can contain or be impregnated with a germicide or other treatment to reduce the risk of contamination to the user from a needle. The device of the invention preferably also has means for gripping the needle and restricting withdrawal of the needle from the restraining medium during flexing of the needle. This means can be provided by the upper surface of the restraining medium where this grips the shank of the needle sufficiently. Alternatively, a separate gripping member can be provided, for example the rubber or soft plastic membrane or collar described above through which the needle penetrates to enter the main body of the container. The gripping member can be formed with pre- formed apertures through which the needle is to pass and such apertures can incorporate saw tooth lips or other means whereby retraction of the needle from the aperture is prevented. The gripping member is located above, at or closely adjacent the exposed upper surface of the restraining medium so that the shank of the needle is gripped closely adjacent the point at which it is mounted in the body of the syringe. As indicted above, the gripping member is conveniently provided by the membrane or sheet over the open end of the container. This is axially depressed as the end of the syringe carrying the needle bears against it when the needle is inserted into the container. This serves to maintain the membrane in contact with the end of the body of the syringe and thus to ensure that flexing of the needle is maximised at this point so that breakage occurs there and not elsewhere along the length cf the needle. As indicated above, two or more such gripping members can be mounted at axially spaced intervals within the container so that the shank of the needle is gripped at a number of axially separated points. We have found that the combination of lateral and axial restraints described above will usually ensure that the shank of the needle breaks at or closely adjacent the point at which the needle is mounted in the end of the syringe body without the need for any moving parts, such as cutter blades. The restraining means provides a simple and effective means for achieving the lateral restraint required for breaking the needle or its mounting and for retaining the separated needle within the container, thus minimising risk of accidental contact with the separated needle by a user. In use, the distal end of the needle of a used syringe is inserted into through the open top, or the membrane covering it, of the container and into the restraining medium held within the container. The syringe body is pressed home against the membrane or the exposed face of the restraining medium. The body of the syringe is then flexed about the longitudinal axis of the needle. Preferably, the syringe is flexed through the maximum angle possible in one plane and is not rotated about the axis of the needle so as to maximise the flexing of the needle. It is therefore preferred that the upper surface of the device of the invention be substantially flat and present the minimum obstruction to the flexing of the syringe. Typically, the needle will snap off at its mounting in the body of the syringe after two or three flexes through 120 to 180° about the axis of the needle. When the needle has snapped off, the syringe can be disposed of with reduced risk and the needle remains held within the restraining medium in the container. The container can then be closed by re-applying its lid to retain the needles securely. DESCRIPTION OF THE DRAWINGS: The invention will now be described by way of illustration only with respect to a number of preferred forms thereof as shown in the accompanying drawings in which Figure 1 is a perspective view of a container containing a foamed plastic pad with a closeable lid; Figure 2 is a vertical section through the container of Figure 1 with the lid in the closed position; Figures 3 and 4 are perspective views of alternative forms of the container of Figure 1; Figure 5a to 5c show the container of Figure 1 in use; Figure 6 shows an alternative form of the device of the invention and Figures 7a and 7b show that device in use; Figure 8 shows an alternative form of the device of Figure 6 and Figure 9 shows the device of Figure 8 in use; Figure 10 is a diagrammatic vertical section through an alternative form of the device of Figure 1; Figure 11 is a perspective view of an alternative form of device to that of Figure 1 and Figure 12 is a sectional view of the device of Figure 11; and Figure 13 illustrates the operation of the foamed plastic restraining member. DESCRIPTION OF THE PREFERRED EMBODIMENTS: The device of Figure 1 comprises a conventional cylindrical plastic tub 1 having an integral hinged top 2 and containing a pad 3 of closed pore polyester or Neoprene foam having a density of 200 Kgs per metre cube. The depth of the tub 1 and of pad 3 are such that the needle 5 of a hypodermic syringe 6 can be fully inserted into the foam pad. In place of the foamed plastic, the pad 3 can be formed by winding cloth, paper, blotting paper or other fibrous material about a central core to provide a generally cylindrical pad with the interfaces between successive layers of the paper aligned axially so that a needle can be inserted between them. The tub 1 can be of circular cross-section as shown in Figure 1 or can have a squared or semi-circular cross- section as shown in Figures 2 and 3 or Figure 11 or any other suitable shape. As shown in Figure 2, the lid can be provided with clips 4 or other means whereby the lid is held in the open position during use. The needle 5 of a syringe is pushed into the pad 3 until the free end of the syringe beds against the top face of pad 3. ' The needle is held firmly within the pad both axially and laterally. If desired, a rubber or other membrane 7, shown dotted in Figure 2, can be applied over the top of the pad to enhance the axial grip on the needle 5. The body 8 of the syringe 6 is then flexed about the axis of the needle 5, which is prevented from following the flexing by the restraining action of pad 3 and the membrane 7. The needle will snap off at the point where it enters the syringe body to provide, as shown in Figure 5c a syringe body without any significant projecting needle stump, the broken off sections of the needle being retained within the pad 3, as shown in Figure 2, for subsequent disposal when the pad is full. In the form of device shown in Figure 6, the container is provided by a cylindrical extension 10 to the protective cap 11 normally used to protect the needle 12 of the syringe 13 before use. A pad 14 of foamed plastic is mounted within the bore 15 of the extension 10 and the free, open end of the bore is closed with a transverse rubber or similar membrane 16, as shown dotted in Figure 7. In use, as shown in Figure 7a, the needle 12 is pushed through the membrane 16 and into the pad 14 until the free end of syringe 13 beds against the outer face of the membrane 16 or pad 14. The syringe is then flexed to and fro until the needle snaps off and is retained in the bore 15 by means of the pad 14 and the membrane 16, as shown in Figure 7b. In the device shown in Figures 8 and 9, the push button end 30 of the plunger 31 of the syringe is formed as a hollow socket which carries a foam plastic pad 32 therein, optionally with a membrane over the open end of the pad 32. When the syringe has been used, the plunger 30 is pulled out of the barrel 33 of the syringe, the needle 34 is inserted into the pad 31 and broken off as shown in Figure 9 by flexing the syringe body to and fro. In the device shown in Figure 10, the tub 1 of the device shown in Figure 1 has had the pad 3 removed. A transverse set of radial arms 40 supports a substantially central hub 41 having a central bore 42. This bore may optionally carry a plug of silicone rubber or may be a narrow unencumbered bore. The arms are located from one third to halfway down the depth of the tub. A similar spider 43 and hub 44 assembly is located immediately below the upper open end of the tub. The open top of the tub is closed by a rubber membrane 45. In use, the needle is inserted through the bores in the two hubs 44 and 41 which thus restrain the needle from lateral flexing, the membrane 45 restraining the needle from axial movement. When the body of the syringe is flexed to and fro, the needle breaks off and will usually drop through the bores in the hubs to lie in the base of the tub as shown, leaving the bores free to accept the needle of another syringe. In the device shown in Figure 11, the container is in the form of a rectangular hollow housing 50 having a needle entry port in its upper face. The upper face is formed with a generally semi-circular cross-section groove 51 which accommodates the body 52 of the syringe at the extremes of its flexing. The groove 51 is provided with a substantially centrally located recess 53 to accommodate the needle mounting block of the syringe. The needle entry port is in the form of a tube 54 extending from the recess 53 into the interior of the housing 50. The needle of the syringe is a loose fit in tube 54, but tube 54 provides sufficient lateral restraint to " cause the needle to flex and break when the syringe body is flexed to and from as shown dotted in Figure 11. There is sufficient clearance between the foot of the tube 54 and the basal wall 55 of the housing 50 for a needle to drop clear of the tube 54 into the housing 50 when it breaks away from the body of the syringe. The lip of the mouth of tube 54 acts as the fulcrum about which the needle flexes. As shown in Figure 13, we believe that a foam plastic restraining member may act to provide at least part of the fulcrum effect required to localise the flexing of the needle by being trapped between the shank of the needle 60 and the shoulder 61 of the syringe body or the needle mounting 62 as shown in Figure 13e. This enables the needle to flex about a specific point as shown in Figures 13a-d, the remainder of the restraining member 63 providing lateral restraint to the length of the shank of the needle 60. The invention has been described above in terms of flexing the needle or its mounting so as to cause breaking. However, the present invention can be applied to syringes or other devices where the needle is secured by a push fit or other separable mounting on the syringe body, in which case the needle is removed from the syringe or other article by separation of the mounting means rather than breakage thereof.

Claims: CLAIMS : 1. A device for use in separating a capillary bore needle from an article on which one end of the needle has been mounted for use of the needle, which device is characterised in that it comprises a hollow body having a capacity to contain a plurality of needles and configured so as to receive through an opening in a face of the body substantially the full length of the needle protruding from the article, the body having at or adjacent the said opening means which are adapted to support and restrain the needle from lateral movement when inserted into the body and to provide a fulcrum about which the needle or its mounting in the article can be flexed so as to cause separation of the needle from the article, the body serving to contain the needle when it has been separated from the article. 2. A device as claimed in claim 1, characterised in that the hollow body is also provided with means which is adapted to restrain the needle from free axial movement within the body during flexing of the needle. 3. A device as claimed in either of claims 1 or 2, characterised in that the means for providing at least part of the fulcrum effect is provided by a restraining member within the hollow body. 4. A device as claimed in claim 3, characterised in that the restraining member is a foamed plastic body which prevents the needle from flexing by more than 30° about its longitudinal axis. 5. A device for use in separating a capillary bore needle from an article on which one end of the needle has been mounted for use of the needle, which device comprises a hollow body configured so as to receive through an opening in a wall of the body substantially the full length of the needle protruding from the article, the body containing a restraining medium adapted to receive the needle and to support the needle against lateral movement so as to provide a fulcrum at. or adjacent the opening in the wall of the body about which the needle or its mounting in the article can be flexed so as to cause separation of the needle or its mounting from the article, the body serving to contain the needle when it has been separated from th.e article. 6. A device as claimed in either of claims 3 or 5, characterised in that the restraining member is provided by a pad of foamed plastic material which undergoes a reduction in volume of from 5 to 25% when a 1 cm cube of the material is subjected to a load of 1kg per square cm. 7. A device as claimed in any one of the preceding claims, characterised in that a flexible membrane is provided across the opening to the hollow body. 8. A method for separating a capillary bore needle from a supporting article at substantially the point at which the needle projects from the article, which method is characterised in that it comprises inserting the distal end of the needle into the hollow body of a device as claimed in any one of claims 1 to 7 and flexing the article transversely to the longitudinal axis of the needle whereby the needle is caused to separate from the article and be retained in the body. 9. A method as claimed in claim 8, characterised in that the needle is the needle of a syringe.

Inventors: SAMS BERNARD, SAMS, BERNARD
Applicants: SAMS BERNARD, SAMS, BERNARD
Application year: 1991
Main classification: A61M5
IPC codes: A61M5