GB2273244A

GB2273244A - Hypodermic needle guard assembly

Info

Publication number: GB2273244A
Application number: GB9300389A
Authority: GB
Inventors: Michael John Taylor
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-12-10
Filing date: 1993-01-11
Publication date: 1994-06-15
Also published as: GB9300389D0

Abstract

The assembly comprises a hub 2 carrying the hypodermic needle and connectable via a threaded recess 13 to the end of a hypodermic syringe and a guard sleeve 4 for the needle which is movable to the guarding position shown in Fig. 4 to shield the dispensing tip of the needle. The guard is secured in the latter position by the engagement of projections 5, 6 in recesses 9, 10 of the hub while further projections 7, 8 abut ramped hub portions 11, 12 to ensure that the sleeve is not accidentally pulled over the hub. The hub and sleeve may be of octagonal cross-section where they overlie. <IMAGE>

Description

Hypodermic needle assemblv The present invention relates to a hypodermic needle assembly.

It is known, for example from European patent specification 0250104 and U.S. Patent 4747837, to provide a protective guard slidable longitudinally of a syringe and needle to cover the pointed tip of a hypodermic needle. The devices disclosed in the documents referred to require the guard to be slidably mounted on the barrel of the syringe such that in the position in which the needle is guarded, corresponding engagement means on the guard and syringe barrel are securely engaged with one another. Both the needle and syringe must then be discarded.

An improved hypodermic needle assembly has now been devised.

According to the invention, there is provided a hypodermic needle assembly comprising a hub arranged to carry said hypodermic needle, said hub being connectable to the end of a hypodermic syringe, guard means being provided for said needle, said guard means being movable to a guarding position in which the dispensing tip of said needle is substantially shielded by said guard means, wherein said guard means is secured in said guarding position by means of engagement of complementary securing formations provided on said guard means and said hub.

Since the complementary securing formations are provided on the hub and guard means, the hypodermic needle, hub and guard means may be removed, as one, from the end of the hypodermic syringe. This enables the hypodermic syringe to be re-used with a sterilised replacement needle assembly.

Typically, the hub is therefore provided with formations arranged to complementarily removably connect with corresponding formations provided on the end of the hypodermic syringe.

Typically, the end of the hypodermic syringe will be provided with an outwardly projecting nipple (usually apertured thereby permitting fluid to pass therethrough) to which the hub is arranged to be connected. Typically, connection of the hub to the end of the syringe will be by means of a screw thread, friction grip connection or the like.

Advantageously, the guard means comprises a hollow tube or the like, which is slidable longitudinally of the needle to the guarding position. Advantageously, the guard means is at least partially translucent and preferably comprises a plastics material.

It is preferred that the complementary engaging securing formations are provided around the periphery of the hub and guard means.

Advantageously, the complementary engaging securing formations comprise at least one projection and corresponding recess arranged to engage one another in the guarding position.

In a preferred embodiment, the recess will be provided on the hub whilst the projection will be provided on the interior of the guard means. In this embodiment, the hub will advantageously taper outwardly from the point of connection to the syringe such that in moving the guard means to the guarding position, the projection provided on the guard means will first pass over a tapered portion of the hub before engaging in the complementary recess provided on the hub.

Advantageously, the guard means and hub are provided with shaped portions arranged such that rotation of the guard means about the longitudinal axis of the needle causes the hub also to rotate about the longitudinal axis of the needle. In order to achieve this, portions of the guard means and hub may be of hexagonal/octagonal or like outer surface profile.

It is preferred that a portion of the hub projects transversely to the axis of the hypodermic needle by a distance which is greater than the extent to which the barrel of the hypodermic syringe projects transversely to the axis of the hypodermic needle.

The invention will now be further described in a specific embodiment, by way of example only, and with reference to the accompanying drawings, in which; Figure 1 is a schematic sectional view of a hypodermic needle assembly according to the invention; Figures 2 to 4 are sectional views of the hypodermic needle assembly of Figure 1 in sequential stages of use when connected to a hypodermic syringe; and Figure 5 is a transverse cross-sectional view along x-x in Figure 4.

Referring to the drawings, and initially to Figure 1 in particular, there is shown a hypodermic needle assembly generally designated 1. Assembly 1 comprises a plastics moulded hub 2 provided with an axial bore through which passes a hypodermic syringe needle 3. The needle 3 is typically fixed by suitable cement or bonding medium inside the axial bore of hub 2.

A substantially transparent plastics guard sleeve 4 is fitted to the exterior of hub 2 and is slidable in the longitudinal direction of needle 3 over hub 2. Primary engagement projections 5, 6 are provided around the interior of the guard sleeve 4 at a first longitudinal location thereof, with similar secondary engagement projections 7,8 being spaced longitudinally therefrom.

Primary receiving recesses 9,10 are provided around the periphery of hub 2 and the proximal end of hub 2 is provided with tapered or ramped portions 11,12. The proximal end of hub 2 is also provided with a threaded recess 13 coaxial with the bore of the hub 2.

The primary and secondary projections typically comprise respective substantially continuous ridges extending transversely around the sleeve. Typically, the primary receiving recess comprises a substantially continuous channel extending transversely around periphery of hub 2.

In use, the needle assembly 1 is supplied in the form shown in Figure 1. The hub 2 is connected to the end of a hypodermic syringe 14 by means of threaded engagement of the syringe nipple projection 15 with the threaded recess 13 at the proximal end of the hub 2. The proximal end of the hypodermic needle therefore extends through nipple projection 15 into the interior of the syringe 14. This is the configuration shown in Figure 2, where it should be noted the pointed, distal end of needle 3 is protected by guard sleeve 4.

When the hypodermic syringe is to be used, the guard sleeve 4 is retracted to the position shown in Figure 3 such that the required fluid may be injected into the patient via the pointed end of needle 3. Subsequent to injection, the guard sleeve 4 is urged in the direction of the hub 2 such that primary engagement projections 5,6 pass up and past ramped portions 11,12 of hub 2 (thereby resiliently outwardly deforming the respective portion of the guard shield 4) until projections 5,6 "snap back" and engage in primary receiving recesses 9.10 in a "snap fit" manner (see Figure 4). In this guarding position, the guard sleeve is securely fixed relative to the hub 2 in the longitudinal direction, and the distal end 4a of guard sleeve 4 extends beyond the pointed distal end 3a of needle 3, thereby substantially reducing the risk of needle stick injury to medical personnel. In the guarding position, secondary engagement projections 7,8 abut the ramped portions 11,12, thereby ensuring that guard sleeve 4 will not be accidentally pulled over hub 2 even in the event of failure of primary projections 5,6.

Referring to Figure 5, it is clearly shown that the respective transverse cross-sections of the hub 2 and sleeve 4 in the region where they overlie one another are octagonal. This feature enables rotation of the sleeve 4 about the axis of the needle 3 to cause corresponding rotation of the hub 2, and thereby enables the hub 2 to be unthreaded from nipple 15 and thereby disengaged from syringe 14. The needle assembly 1 may therefore be discarded safely and replaced by a new, sterilised assembly, whilst the syringe 15 may be re-used.

Claims

Claims:

1. A hypodermic needle assembly comprising a hub arranged to carry said hypodermic needle, said hub being connectable to the end of a hypodermic syringe, guard means being provided for said needle, said guard means being movable to a guarding position in which the dispensing tip of said needle is substantially shielded by said guard means, wherein said guard means is secured in said guarding position by means of engagement of complementary securing formations provided on said guard means and said hub.

2. A hypodermic needle assembly according to claim 1, wherein the hub has formations arranged to complementarily removably connect with corresponding formations provided on the end of the hypodermic syringe.

3. A hypodermic needle assembly according to claim 1 or 2, wherein the end of the hypodermic syringe has an outwardly projecting apertured nipple to which the hub is arranged to be connected.

4. A hypodermic needle assembly according to any of claims 1 to 3, wherein the guard means comprises a hollow tube or the like, which is slidable longitudinally of the needle to the guarding position.

5. A hypodermic needle assembly according to any of claims 1 to 4, wherein the guard means is at least partially translucent and comprises a plastics material.

6. A hypodermic needle assembly according to any of claims 1 to 5, wherein the complementary engaging securing formations are provided around the periphery of the hub and guard means.

7. A hypodermic needle assembly according to any of claims 1 to 6, wherein the complementary engaging securing formations comprise at least one projection and corresponding recess arranged to engage one another in the guarding position.

8. A hypodermic needle assembly according to any of claims 1 to 7, wherein the recess is on the hub and the projection is on the interior of the guard means.

9. A hypodermic needle assembly according to claim 8, wherein the hub tapers outwardly from the point of connection to the syringe such that in moving the guard means to the guarding position, the projection provided on the guard means will first pass over a tapered portion of the hub before engaging in the complementary recess provided on the hub.

10. A hypodermic needle assembly according to any of claims 1 to 9, wherein the guard means and hub have shaped portions arranged such that rotation of the guard means about the longitudinal axis of the needle causes the hub also to rotate about the longitudinal axis of the needle.

11. A hypodermic needle assembly according to any of claims 1 to 10, wherein a portion of the hub projects transversely to the axis of the hypodermic needle by a distance which is greater than the extent to which the barrel of the hypodermic syringe projects transversely to the axis of the hypodermic needle.

12. A hypodermic needle assembly substantially as described herein with reference to the accompanying drawings.