Safety needle assembly for use with a medical injector

1 . A safety needle assembly for use with a medical injector comprising;

a tubular housing removably attachable to the medical injector, the tubular housing extending in a longitudinal direction from a proximal end to a distal end, the proximal end being arranged for attachment to the medical injector;

a needle mount located within the tubular housing for directly or indirectly supporting a double ended needle having a patient end and a non-patient end, the needle mount being arranged to allow movement of the needle, including rotation about an axis of rotation, from an operative position to a shielding position;

a spring member to urge movement of the needle to the shielding position; and

a releasable blocking member arranged to prevent movement of the needle from the operative position whereat the needle extends in a direction along a longitudinal axis of the tubular housing and whereby release of the blocking member allows movement of the needle to the shielding position;

wherein the needle mount is a unitary component inserted into the tubular housing and fixedly retained in the tubular housing to fix the axis of rotation of the needle relative to the tubular housing, the axis of rotation intersecting the longitudinal axis of the tubular housing, and the spring member arranged to urge rotation of the needle about said axis of rotation; and

wherein the blocking member comprises a control member slidably displaceable along the longitudinal axis of the tubular housing from a set position whereat the control member engages the needle mount to maintain the needle in the operative position before use, and thereafter, attachment of the safety needle assembly to the medical injector, the use thereof, and subsequent detachment of the safety needle assembly from the medical injector, causes the control member to move away from the set position and disengage from the needle mount to allow the spring member to move the non-patient end of the needle towards the distal end of the tubular housing by rotating the needle to the shielding position whereat the needle extends at an angle oblique to the longitudinal axis of the tubular housing to place the non-patient end of the needle at a location adjacent to an interior wall of the tubular housing.

2 . The safety needle assembly according to claim 1 , in which the attachment of the safety needle assembly to the medical injector, the use thereof, and subsequent detachment of the safety needle assembly from the medical injector, causes the control member to move away from the set position and disengage from the needle mount to allow the spring member to rotate the needle to the shielding position, wherein the spring member is arranged to ensure that the non-patient end of the needle moves distally and not proximally.

3 . The safety needle assembly according to claim 1 , in which the position of the axis of rotation is defined to: withdraw the non-patient end of the needle in the distal direction and further into the tubular housing, and cause the non-patient end of the needle to locate adjacent to the interior wall of the tubular housing.

4 . The safety needle assembly according to claim 1 , wherein the axis of rotation is statically fixed relative to the tubular housing and the non-patient end moves in a circumferential path about the axis of rotation from the operative position to the shielding position.

5 . The safety needle assembly according to claim 1 , in which, in the shielding position, the non-patient end of the needle contacts the interior wall, which is an internal peripheral wall of the tubular housing.

6 . The safety needle assembly according to claim 1 , wherein the control member comprises an engagement aperture and a part of the needle mount is arranged, in the set position, to locate within the engagement aperture to prevent rotation of the needle from the operative position.

7 . The safety needle assembly according to claim 6 , in which the control member comprises an annular member and the engagement aperture is located centrally on the annular member.

8 . The safety needle assembly according to claim 6 , in which the needle mount comprises a collar which locates within the aperture of the control member in the set position.

9 . The safety needle assembly according to claim 1 , in which the spring member comprises a resilient member which extends inwardly from the tubular housing and contacts an outer surface of the needle mount at a position offset from the axis of rotation.

10 . The safety needle assembly according to claim 1 , in which the spring member comprises a leaf spring projecting inwardly from the tubular housing and, with the needle in an operative position, the leaf spring is in a deflected position relative to a neutral position.

11 . The safety needle assembly according to claim 10 , in which an end surface of the leaf spring contacts an outer longitudinal surface of the needle mount to create a torque about the axis of rotation.

12 . The safety needle assembly according to claim 1 , in which the needle mount comprises a unitary component having axial members located on an outer surface.

13 . The safety needle assembly according to claim 12 , in which the tubular housing comprises axial members located on an internal surface for cooperation with the axial members provided on the needle mount.

14 . The safety needle assembly according to claim 13 , in which the axial members of the needle mount and the axial members of the tubular housing enable a push fit engagement of the needle mount into the tubular housing to fixedly retain the needle mount in the tubular housing.

15 . The safety needle assembly according to claim 13 , wherein the axial members of the tubular housing and the axial members of the needle mount comprise a first pair of axial members comprising projecting portions and a second pair of axial members comprising corresponding recesses.

16 . The safety needle assembly according to claim 15 , in which the projecting portions comprise hemi-spherical projections.

17 . The safety needle assembly according to claim 1 , in which the control member is mounted to move away from the proximal end of the tubular housing in order to disengage the needle mount.

18 . The safety needle assembly according to claim 1 , comprising a needle shielding sleeve and, in which, the control member comprises a distal end face of the needle shielding sleeve which provides an engagement aperture to prevent rotation of the needle from the operative position whilst the control member is in the set position.

19 . The safety needle assembly according to claim 1 , in which the control member comprises a disc, the disc being located within a needle shielding sleeve of the safety needle assembly and wherein the disc is slidably displaceable in the needle shielding sleeve from the set position, and wherein the control member is frictionally engaged in the needle shielding sleeve and is maintained in a position located adjacent to a distal end of the needle shielding sleeve on movement thereto by the tubular housing during an injection.

20 . The safety needle assembly according to claim 1 , in which the control member comprises a distal end face and a skirt portion extending therefrom, the distal end face comprising an aperture for engaging an outer surface of the needle mount in the set position and the skirt providing a contact face which is contacted by part of the medical injector in the set position, and the control member is moved from the set position on attachment of the safety needle assembly to the medical injector.

21 . The safety needle assembly according to claim 1 , in which the control member is mounted to move towards the proximal end of the tubular housing in order to disengage the needle mount.

22 . The safety needle assembly according to claim 21 , in which a needle shielding sleeve encompasses and shields the patient end of the needle in a non-injecting configuration and, in which, the needle shielding sleeve comprises a release member to slidably displace the control member from the set position.

23 . A drug delivery device comprising a safety needle assembly and a medical injector, the safety needle assembly being in accordance with claim 1 .

24 . The drug delivery device according to claim 23 , in which the medical injector comprises a rubber seal and attachment of the safety needle assembly to the medical injector causes the non-patient end of the needle to pierce and penetrate through the rubber seal and wherein the position of the non-patient end though the rubber seal maintains the needle in the operative position after the control member has moved from the set position.

25 . A method of shielding a non-patient end of a needle in a safety needle assembly for use with a medical injector, the safety needle assembly comprising;

a tubular housing removably attachable to the medical injector, the tubular housing extending in a longitudinal direction from a proximal end to a distal end, the proximal end being arranged for attachment to the medical injector;

a needle mount located within the tubular housing for directly or indirectly supporting a double ended needle having a patient end and a non-patient end, the needle mount being arranged to allow movement of the needle, including rotation about an axis of rotation, from an operative position to a shielding position;

a spring member to urge movement of the needle to the shielding position; and

a releasable blocking member arranged to prevent movement of the needle from the operative position whereat the needle extends in a direction along a longitudinal axis of the tubular housing and whereby release of the blocking member allows movement of the needle to the shielding position;

wherein the needle mount is a unitary component inserted into the tubular housing and fixedly retained in the tubular housing to fix the axis of rotation of the needle relative to the tubular housing, the axis of rotation intersecting the longitudinal axis of the tubular housing, and the spring member arranged to urge rotation of the needle about said axis of rotation; and

wherein the method comprises;

slidably displacing a control member of the blocking member along the longitudinal axis of the tubular housing from a set position whereat the control member engages the needle mount to maintain the needle in an operative position before use by:

attaching the safety needle assembly to the medical injector,

performing an injection using the safety needle assembly and the medical injector, and

subsequently detaching the safety needle assembly from the medical injector,

which causes the control member to move away from the set position and disengage from the needle mount to allow the spring member to move the non-patient end of the needle towards the distal end of the tubular housing by rotating the needle to the shielding position whereat the needle extends at an angle oblique to the longitudinal axis of the tubular housing to place the non-patient end of the needle at a location adjacent to an interior wall of the tubular housing.