WO1992012748A1

WO1992012748A1 - Protection of needle points

Info

Publication number: WO1992012748A1
Application number: PCT/GB1992/000128
Authority: WO
Inventors: Paul Giles Miller
Original assignee: Paul Giles Miller
Priority date: 1991-01-24
Filing date: 1992-01-22
Publication date: 1992-08-06
Also published as: AU1171192A; GB9101525D0

Abstract

A plunger (23) is removed from a syringe and the point of a needle which has been used on the syringe is then guided into a socket (26) on the plunger by causing relative transverse movement before pushing the needle home into the socket (26). During the pushing home of the needle the point extends through a retaining washer (5) with the point of the needle being located within a protective region. The plunger can then be twisted to break the needle off the barrel of a syringe, and the barrel can then be relocated within the barrel of the syringe.

Description

PROTECTION OF NEEDLE POINTS

The present invention relates to needle storage apparatus, a syringe adapted to protect a sharp end of a needle and a method of protecting the sharp end of a needle. The invention is particularly, although not exclusively, applicable in relation to protecting the points of needles used in syringes.

For many years now the medical and nursing profession have used disposable plastic hypodermic syringes. Ever since these have been used there has been a problem as to how safely the used syringes and their detachable disposable needles should be got rid of.

In recent years, the answer has been the special needle safe disposable bins. These are then removed separately from other clinical waste and either burned at very high temperature, or sometimes "solidified" by adding a resin mixture. Despite these bins, personnel still get needlestic injuries, either when transferring to the bins or when needles are carelessly disposed of in general waste. Further, with the enormous problems which are now being found with auto-immunisation by these needles with such infections as H.I.V. and Hepatitis, and with the still spreading use of intra-venous drug abuse, it is essential that needles should be made as harmless as possible and that syringes should not be able to be used more than once.

According to one aspect of the present invention, needle storage apparatus includes a protective region arranged to protect a sharp end of a needle and control means arranged to permit a needle to be moved into the protective region, but inhibit movement of the needle away from the protective region.

The needle storage apparatus may comprise a plunger of a syringe having the protective region.

According to another aspect of the present invention a syringe includes a barrel and a plunger adapted to slide within the barrel, the plunger being adapted to protect a sharp end of a needle which has been used with the syringe within a protective region of the plunger.

The plunger may be arranged to be located in the barrel after the sharp end of the needle has been located in the protective region.

According to a further aspect of the present invention, needle storage apparatus includes a protective region arranged to receive the point of a needle initially by relative transverse movement of a needle and the protective region until the point of a needle faces the protective region, with the protective region being arranged to receive the point of a needle by relative movement of a needle and the protective region in the direction of extent of a needle.

The apparatus may include a guide arranged to locate the needle during relative transverse movement or during subsequent relative movement or both.

Control means may be provided which are arranged to inhibit movement of the sharp end of a needle away from the protective region. The control means may be arranged to prevent movement of a sharp point of a needle through the protective region or, alternatively or additionally, back out from the direction in which it was inserted into the protective region.

The control means may be arranged to permit sliding movement of a needle in one direction with a point of the needle moving towards the protective region, but inhibit sliding movement in an opposite direction.

The control means may include at least one flexible member arranged to exert a greater force on a needle upon attempted movement of a needle away from the protective region than any force which the flexible member may be arranged to exert on the needle upon movement of a sharp point of the needle towards the protective region. The control means may include a pair of opposed flexible portions arranged to act on opposed sides of a needle, and two pairs of opposed flexible portions may be arranged to act on opposed sides of a needle. The flexible portion or portions may be arranged to act around substantially the complete periphery of a needle. The control means may be arranged to inhibit movement of a variety of diameters of needles away from the protective region.

According to another aspect of the present invention a method of protecting the sharp end of a needle comprises storing the sharp end of a needle by moving the sharp end towards a protective region and inhibiting movement of the sharp end of the needle away from the protective region.

The method may comprise storing the sharp end of a needle in a protective region of a plunger. According to a further aspect of the present invention a method of protecting the sharp end of a needle comprises locating the sharp end of a needle within the plunger of a syringe.

The method may comprise locating the plunger in the barrel of a syringe after the sharp end of a needle has been located in the plunger.

According to another aspect of the present invention a method of storing a needle comprises causing initial relative transverse movement between the extent of a needle and a protective region, and then causing relative movement between the needle and the protective region in the direction of the extent of the needle in order to move the needle into the protective region.

The method may comprise the sides of the needle being guided during the relative movement transverse to the extent of the needle or, alternatively or additionally, during the relative movement in the direction of the extent of the needle.

The method may comprise the plunger being located substantially completely within the barrel of the syringe.

The method may comprise removing the plunger from the barrel of a syringe, receiving the sharp point of a needle within the plunger and then relocating the plunger within the barrel of the syringe. The method may comprise locating the sharp point within the plunger whilst the needle is mounted on the barrel. The method may comprise removing the needle from the barrel by breaking a portion of the barrel. The method may comprise inhibiting or preventing movement of the sharp point of the needle away from its location within the plunger.

The method may comprise inhibiting movement of the sharp point of the needle through a protective region. Alternatively or additionally the method may comprise inhibiting movement of the sharp point of the needle back out of a protective region from the direction in which the sharp point was moved into the protective region.

The method may comprise permitting sliding movement of the needle in one direction, towards a protective region but inhibiting sliding movement in the opposite direction.

The method may comprise a flexible member exerting a greater force on the needle upon attempted withdrawal of the needle away from a protective region than any force which the flexible member may exert on the needle upon movement of the point of the needle towards the protective region. The method may comprise arranging for a pair of opposed flexible portions to act on opposed sides of a needle upon attempted withdrawal, and the method may comprise two such pairs of opposed flexible portions being arranged to act on opposed sides. The method may comprise exerting a force around substantially the complete periphery of a needle upon attempted movement of the point of a needle away from the protective region.

The present invention includes any combination of the herein referred to features or limitations.

The present invention may be carried into practice in various ways, but one embodiment will now be described by way of example and with reference to the accompanying drawings, in which:-

Figure 1 is a cross-section through a first embodimen of a syringe 1;

Figure 2 is a cross-section through part of a barrel 2 and a plunger 3 of the syringe 1 showing the detachment of a needle 4 from the syringe;

Figure 3 is a cross-section through the syringe after the needle 4 has been stored in the plunger 3;

Figures 4 and 5 are respectively side and plan views of a retaining washer 5 which is adapted to allow a needle to be inserted into the barrel but prevent withdrawal therefrom,

Figure 6 is a plan view of a modified retaining washer;

Figure 7 is a schematic view of the end of an alternative plunger 23;

Figure 8 is a schematic perspective view of the plunger 23 shown in Figure 7 about to receive the needle 4 of a syringe, and

Figure 9 is a view similar to Figure 8 with the needle co-operating with the plunger and about to be pushed into the plunger.

As shown in Figure 1, the plunger 3 is slidably mounted within the cylindrical barrel 2 of the syringe. A rubber washer 6 seals around the periphery of the internal wall of the barrel. The washer is constrained to move within the barrel with the plunger by means of an inwardly projecting rib 7 formed on a sleeve 8 of the washer, which surrounds the end of the plunger, extending into a circular groove 9 extending around the plunger.

The needle 4 is provided with an attachment member 10 which includes a cylindrical recess 11. The recess 11 is pushed over, and is a tight fit on an outlet tube 12 extending form the end of the barrel 2.

In use, the plunger can be moved away from the needle and the co-operation of the rubber washer 6 with the barrel causes a reduced pressure to be applied to the bore of the needle via the outlet tube 12 thereby permitting fluid to be taken into the chamber. That fluid may either be taken from a body or may be taken from a fluid to be injected into a body by returning the plunger towards the outlet tube 12.

When the operation of the syringe is finished, the plunger is moved to the left, when viewed in Figure 1, completely out of the barrel 2. The seal 6 travels with the plunger in the barrel until it abuts an inwardly directed flange 13 located at the other end of the barrel to the outlet tube. That abutment causes the rib 7 to be restrained from further movement to ensure that the plunger becomes detached from the washer with the rib 7 of the washer leaving engagement with the groove 9 of the plunger. Thus the washer is left away from the outlet tube 12 adjacent to the end of the barrel 2.

The plunger is then manoeuvred such that the tip 14 of the needle faces an inwardly tapering surface 15 formed on a plastic insert 16 at the end of the plunger. Relative movement of the needle tip and the plunger towards each other causes the tip of the needle to be guided by the tapering surface 15 into the body of the plunger until the tapering surface 15 wedges with the corresponding tapered surface 16 formed on the outside of the attachment member 10 provided on the needle. The parts are then in the position shown in Figure 2.

The barrel 2 and the plunger 3 can then be gripped firmly, one in each hand of the operator, and the parts can be twisted relative to each other, for instance in the direction indicated by the arrows 17 to cause the outlet tube 12 to fracture at the location 18. If desired, the outlet tube can be weakened, for instance by being of reduced cross-sectional area, at the intended location of the fracture in order to assist in the separation of the needle from the barrel.

The plunger is then inserted back into the barrel of the syringe and pushed down towards the remaining portion of the outlet tube 12 integral with the barrel until the parts occupy the position shown in Figure 3.

All of the possible contaminated parts can then be disposed of as a unit, and the sharp part of the needle is completely concealed and unable to harm or infect persons.

The fracture of the outlet tube 12 ensures that the barrel of the syringe is unable to be used again.

The plunger includes the retaining washer 5 in its internal passage which is arranged to permit the needle to be inserted into the plunger but to prevent withdrawal of the needle either by accident or by a person attempting to reuse the needle. The washer 5 is located within the plunger by first inserting a retaining disc 18 into the plunger. The disc 18 is a tight fit within the bore of the plunger. The washer 5 is then loosely dropped into the plunger to abut with the disc 18, and is held in the plunger by the insertion of the insert 16 having the tapering surface 15. The insert 16 is also a tight fit within the bore of the plunger.

The washer 5 is able to slide to a limited extent transverse to the longitudinal axis of the plunger and, alternatively or additionally, may be a loose fit in the direction of the extent of the bore. Furthermore, as shown in Figure 4, the washer is cone shaped in the direction in which it extends into the plunger. Accordingly when the end of the needle is inserted into the barrel the tip tends to slide up the cone, towards an opening 19 formed at the top of the cone, and the cone may be deflected slightly to the side in order to assist in location of the tip with the opening. The opening 19 may be 0.4 mm or less in diameter in the unflexed condition of the washer, and may be less in diameter than the smallest 25G needle in current use.

As seen in Figure 5, the washer 5 is provided with four slits 20 extending radially away from the opening. As the needle tip is pushed through the opening 19, the material between these slits is flexed away from the unstressed conical shape shown in Figure 5 to cause the opening to increase in size and allow the needle to be slid into the plunger. The portions of the washer defining the opening are flexed into engagement with the periphery of the needle, and forces attempting to withdraw the needle from the plunger are resisted by the wedging action exerted by those portions on the needle. If the washer is used with a larger diameter needle then the parts of the washer are able to flex to a greater extent and yet still retain the needle.

Figure 6 shows an alternative form of a conical washer to that shown in Figures 4 and 5. In the washer shown in Figure 6 slots 21 are provided in an "H" shape such that the wedging force exerted on a needle to resist attempted withdrawal from the plunger is provided on opposed portions of the needle (rather than around substantially the complete periphery as in the washer shown in Figures 4 and 5) by two flexed panels 22.

The insert 18 is provided with an inwardly tapered end surface in order to allow the insertion and flexure of the conical washers. If desired, the insert 18 could be adhered into place within the bore of the plunger or formed integrally therewith.

The washers shown in Figures 4 to 6 therefore exert an action on the needle similar to that exerted by rivets.

The washers can then be made of any suitable material, such as stainless steel.

Referring now to Figure 8, the plunger 23 includes a tubular wall 24 from which a series of radial fins 25 extend inwardly to an axially extending annular socket 26.

A slot 27 is formed in the annular socket along part of its extent, with access being available to the slot 27 through a portion of the wall 24 which has been removed to define an opening 28. The opening 28 is located between the axial extent of two adjacent fins 25. The socket 26 extends inwardly along the plunger to a greater extent than the opening 28 until it ends at a retaining washer 5. The retaining washer 5 may be of the same form and material as that previously described and may be held in place within the plunger by a friction fit or any other convenient means. Alternatively, the retaining washer may be moulded of plastics. The plunger may be injection moulded.

In use, a rubber washer is attached over the end of the plunger shown in Figure 7 with the washer projecting into the end of the plunger up to the axially facing ends of the ribs, which are set back slightly from the end of the wall 24. The rubber washer remains attached to the plunger whilst the plunger is operative within the barrel as described in relation to the plunger and barrel shown in the other drawings.

When the plunger is pulled out of the barrel, after the syringe has been used, the washer is caused to come off the end of the plunger to expose the end of the socket 26.

As shown in Figures 8 and 9, the needle 4 is brought into the socket 26 by relative movement transverse to the direction in which the needle extends until the point and the majority of the needle are concealed within the socket. As the "V" provided by the fins 25 which lead out to the opening diverge outwardly, the needle is guided into the socket during transverse movement. Thus, during the initial encapsulation of the needle in which the needle is located partially in a protective region, the point is not advanced and there is no danger of the point piercing the hand of an operative. With the point of the needle safely in the socket 26 the needle is then moved relative to the plunger so that the point passes through the socket 26 beyond the opening 28 and through the retaining washer 5, as shown in Figure 9. Further movement of the needle into the plunger brings the attachment member 10 into frictional engagement with the socket, to bring the point of the needle fully into the protective region and the needle can then be detached from the barrel or broken off the barrel as previously described.

The embodiment described in Figures 7 to 9 may include any of the features of the previous embodiments and vice-versa.

Claims

1. A syringe including a barrel and a plunger adapted to slide within the barrel, the plunger being adapted to protect a sharp end of a needle which has been used with the syringe within a protective region of the plunger.

2. A syringe as claimed in Claim 1 in which the plunger is arranged to be located in the barrel after the sharp end of the needle has been located in the protective region.

3. A syringe as claimed in Claim 1 or 2 in which the sharp end of a needle is arranged to be located within the protective region of the plunger by initially causing relative movement of the needle and the plunger in a direction transverse to the extent of a needle, and subsequently causing relative movement of the plunger and the needle in the direction of extent of the needle.

4. A syringe as claimed in Claim 3 in which a guide is included in the plunger which is arranged to locate the needle during relative movement in a direction transverse to the extent of the needle between the needle and the plunger.

5. A syringe as claimed in Claim 3 or Claim 4 in which the plunger includes a guide arranged to locate the needle during relative movement of the needle and the plunger in the direction of extent of the needle.

6. A syringe as claimed in any preceding claim including control means arranged to inhibit movement of the sharp end of a needle away from the protective region.

7. A syringe as claimed in Claim 6 in which the control means are arranged to prevent movement of a sharp point of the needle back out from the direction in which the needle is inserted into the protective region.

8. A method of protecting the sharp end of a needle comprising locating the sharp end of a needle within the plunger of a syringe.

9. A method as claimed in Claim 8 comprising locating the plunger in the barrel of a syringe after the sharp end of a needle has been located in the plunger.

10. A method as claimed in Claim 8 and 9 comprising locating the sharp end of a needle within the plunger by causing initial transverse movement between the extent of the needle and the plunger and then causing relative movement of the needle and the plunger in the direction of the extent of the needle.

11. A method as claimed in Claim 10 comprising guiding the sides of the needle during the relative transverse movement of the plunger and the needle.

12. A method as claimed in Claim 10 or Claim 11 comprising the sides of the needle being guided during relative movement of the needle and the plunger in the direction of extent of the needle.

13. A method as claimed in any of Claims 8 to 12 comprising locating the plunger substantially completely within the barrel of the syringe.

14. A method as claimed in any of Claims 8 to 13 comprising locating the sharp point within the plunger whilst the needle is mounted on the barrel.

15. A method as claimed in Claim 14 comprising removing the needle from the barrel by breaking a portion of the barrel.

16. A method as claimed in any of Claims 8 to 15 comprising inhibiting or preventing movement of the sharp point of the needle away from its location within the plunger.