WO1999062579A1

WO1999062579A1 - Hypodermic needle

Info

Publication number: WO1999062579A1
Application number: PCT/GB1999/001006
Authority: WO
Inventors: John Targell
Original assignee: Nmt Group Plc
Priority date: 1998-05-30
Filing date: 1999-03-31
Publication date: 1999-12-09
Also published as: AR019565A1; GB9811603D0; ID23601A; AU3338599A

Abstract

There is disclosed a combination of a hypodermic needle assembly for connection to the barrel (14) of a syringe and a protective sheath (16) enclosing the assembly until required for use, the assembly and sheath (16) having interengaging means (18, 19) to hold the assembly within the sheath (16) characterised in that the length of the sheath (16) is such that the rim of its open end engages the barrel (14) of the syringe before connection with the syringe is complete whereby completion of the connection forces disengagement of the interengaging means (18, 19).

Description

HYPODERMIC NEEDLE

This invention concerns a hypodermic needle assembly adapted for connection to the barrel of a hypodermic syringe.

Generally such a needle assembly is provided in a protective sheath having one end closed until the assembly is required for use by a sterile seal, for example a tear-off strip of foil. Once the foil is removed, care is needed to ensure that the assembly does not drop from the sheath onto an unsterile surface. Even when the assembly is removed with care, there is a danger of the needle causing injury or becoming contaminated during the operation of connecting the assembly to a syringe.

It is an object of the present invention to provide a hypodermic needle assembly and protective sheath which overcome the problems aforesaid and ensure proper engagement of the needle assembly with the barrel.

This latter is particularly important when the assembly provides for automatic retraction of the needle into the body of the syringe at the completion of the administration of an injection. Such retraction arrangements operate to extremely fine tolerances (unless substantial waste of the material being injected can be tolerated) and would fail if the axial positioning of the assembly and syringe barrel were incorrect.

According to the present invention, there is provided a combination of a hypodermic needle assembly for connection to the barrel of a syringe and a protective sheath enclosing the assembly until required for use, the assembly and sheath having interengaging means to hold the assembly within the sheath, characterised in that the length of the sheath is such that the rim of its open end engages the barrel of the syringe before connection with the syringe is complete whereby completion of the connection forces disengagement of the interengaging means..

The interengaging means may comprise a circumferential rib on the assembly and an indent on the sheath.

The assembly may connect with the syringe by means of a screw thread.

The assembly may connect with the syringe by means of a bayonet-type connection.

There may be an axially extending splined connection between the assembly and the sheath whereby torsional forces applied to the sheath during the connecting operation are transmitted to the assembly.

The invention will be further apparent from the following description with reference to the several figures of the accompanying drawings, which show, by way of example only, one form of needle assembly and protective sheath embodying same.

Of the drawings :-

Figure 1 shows a side elevation of the needle assembly and sheath;

Figure 2 shows a cross-section through the needle assembly and sheath on the line II-II of Figure 1; Figure 3 shows a cross-section through the needle assembly and sheath on the line III-III of Figure 2; and

Figures 4 to 7 show fragmentary cross-sections on an enlarged scale of successive stages in the connection of the needle assembly with the barrel of a hypodermic syringe.

Referring now to the drawings, it will be seen that the needle assembly is generally of the kind disclosed in our European Patent No.0776 225 providing for automatic retraction of the needle 10 into the body of the syringe after administration of an injection. The needle assembly includes an end cap 11 from which the needle 10 extends and a threaded boss 12 adapted to engage with a threaded socket 13 on the forward end of a syringe barrel 14 to connect the needle assembly with the barrel 14.

The assembly is retained, until required for use, in a protective and sterile sheath 16 whose open end is initially closed by a tear-off strip 17 of foil.

A circumferential rib 18 on the assembly engages a circumferential indent 19 within the sheath 16 to hold the assembly within the sheath and prevent it from falling therefrom.

The outer surface of the sheath 16 is knurled at 20 to facilitate its rotation to threadedly engage the boss 12 with the socket 13, torsional forces applied to the sheath 16 being transmitted to the needle assembly by a splined connection between the sheath and assembly comprised by teeth 21 extending outwardly from the end cap 11 engaging keyways 22 in the sheath. The length of the sheath 16 is such that, after removal of the strip 17, the rim of its open end engages the barrel 14 before the threaded connection between the boss 12 and socket 13 is complete whereby completion of the connection forces the sheath forwardly to disengage the rib 18 from the indent 19 and allow the sheath to be removed as shown in Figures 4-7.

It will be understood that the needle is contained within the sheath throughout the connection operation reducing the risk of injury or contamination.

It will be appreciated that it is not intended to limit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof as defined by the appended claims.

Thus, for example, the assembly may connect with the barrel by way of a bayonet-type connection.

Again, for example, the interengaging means between assembly and sheath may be a frangible connection.

Claims

1. A combination of a hypodermic needle assembly for connection to the barrel of a syringe and a protective sheath enclosing the assembly until required for use, the assembly and sheath having interengaging means to hold the assembly within the sheath characterised in that the length of the sheath is such that the rim of its open end engages the barrel of the syringe before connection with the syringe is complete whereby completion of the connection forces disengagement of the interengaging means.

2. A combination according to claim 1 wherein the interengaging means comprise a circumferential rib on the assembly and an indent on the sheath.

3. A combination according to claim 1 or claim 2 wherein the assembly connects with the syringe by means of a screw thread.

4. A combination according to claim 1 or claim 2 wherein the assembly connects with the syringe by means of a bayonet-type connection.

5. A combination according to claim 3 or claim 4 wherein there is an axially extending splined connection between the assembly and the sheath whereby torsional forces applied to the sheath during the connecting operation are transmitted to the assembly.