GB2608102A

GB2608102A - Improved needle safety assembly

Info

Publication number: GB2608102A
Application number: GB2108399.3A
Authority: GB
Inventors: Peter Liversidge Barry
Original assignee: TIP TOP COM Ltd
Current assignee: TIP TOP COM Ltd
Priority date: 2021-06-11
Filing date: 2021-06-11
Publication date: 2022-12-28
Anticipated expiration: 2041-06-11
Also published as: GB2608211A; GB202108399D0; GB202201934D0; GB2608102B

Abstract

The safety needle assembly comprises a needle/cannula 112 mounted in a tubular housing 120. The cannula 112 is located within the needle mount 160 which is located within the tubular housing 120. The shielding sleeve 130 provides the blocking means which retains the alignment of the cannula 110 along the longitudinal axis of the tubular member 120. The blocking means is arranged to counteract the pivoting force of the spring or an ability of the cannula to freely rotate in order to retain the cannula 112 in an operative position. The spring 170 and the needle mount 160 are arranged at a set position and the use of the safety needle assembly 110 with the medical injector 111 causes a shift from the set position. This shift enables the spring 170 to then rotate the needle 112 to the shielding position when the safety needle assembly 110 is detached from the medical injector 111.

Description

Improved Needle Safety Assembly

FIELD OF THE INVENTION

The present invention relates to a safety device for use with a needle having a sharp tip to confer passive protection to that needle. The present invention also relates to a safety needle assembly for use with a medical injector, a drug delivery device comprising a safety needle assembly and a medical injector and a method of shielding a non-patient end of a needle in a safety needle assembly.

The safety device of the present invention is primarily but not exclusively intended for use with a medical needle. The medical needle may be used to penetrate a human or animal body, or may be used for other medical uses such as the penetration of a pierceable membrane of an intravenous medication system.

In the following description all uses of the needle safety assembly will be described simply as the penetration of a body, even though specific embodiments may be intended for other uses.

BACKGROUND TO THE INVENTION

Fluids of various kinds may be administered to a body by means of a hollow needle in conjunction with a source of the required fluid. For example, such a needle may be associated with a syringe holding a liquid drug, the needle being used to penetrate the body of the site at which a drug is to be administered. Equally, body fluids may be withdrawn by using a hollow needle which is used to penetrate the body until the tip is located at the site from which the fluid is to be withdrawn.

One recognised hazard for clinicians and other persons using or handling needles for the above described purposes, is the risk of a so-called needle stick injury. Such injuries are caused by the accidental penetration by the needle. Prior to the use of the needle to supply a fluid or to withdraw fluid from a body, this rarely presents -2 -much of a problem. However, once the needle has been used there is very much a higher risk of serious consequence for the clinician, or others associated with the disposal of a used needle.

Needle stick injuries may be caused by the distal tip of the needle which is used to penetrate through the skin. However, the proximal end of the needle is also sharp since it may be used to pierce or project into a cartridge or container holding the liquid drug. Once the needle mounting assembly is removed from the injecting device, the proximal end of the needle therefore presents a further risk to a clinician or user.

Needle stick injuries from drug delivery devices/safety engineered devices may be prevented by active systems and/or passive systems which provide two different types of safety feature activation methods. In active systems, a user is required to activate the safety mechanism and these may require one handed or two handed activation by the healthcare professional after use. However, in passive systems, no intervention is required from the user and the safety system is activated automatically and specifically does not need any action/steps from the user. In particular, in passive systems the safety features are initiated and activated automatically during use of the device.

The proximal end of the safety needle assembly may include a shielding device for the distal tip and may also comprise a shroud or skirt which affords some protection of the proximal tip. However, needle stick injuries still result from the proximal end of the needle since the tip is still accessible. In addition, the proximal tip is located centrally within the shroud or skirt such that a fingertip could easily make contact with the proximal end needle tip.

A needle safety assembly may include a spring in order to urge the needle to move from an operative position to a shielding position. This spring is assembled directly into a loaded position and a blocking device is arranged to prevent the needle moving from the operative position to the shielding position until the needle has been -3 -used and the injection preformed. Accordingly, the spring may be maintained in the loaded position for a prolonged period. Such springs may be formed from a resilient material which is deformed from an unbiased position to provide the required urging force for the needle and the spring is thereby preloaded. Accordingly, the material must have properties which ensure that the spring capacity does not reduce significantly before the assembly has been used. In addition, the material of the spring must have such inherent properties that the spring does not fail in any way whilst being maintained in a deflected position for a prolonged period. Such properties may dictate the period within which the assembly must be used or may limit the urging force which can be initially preloaded.

In metal springs, the material may be able to maintain the preloaded force. However, metal springs cause problems during assembly and this is a significant problem for devices which are being assembled in high speed assembly processes.

For example, coiled metal springs can nest and cause other issues during assembly.

Springs formed from a plastics material provide advantages since they can be reliably and accurately manufactured and these can also be used in high speed assembly processes. However, any preloading of such resilient material may gradually reduce with time.

It is an aim of the present invention to overcome at least one problem associated with the prior art, whether referred to herein or otherwise.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided 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 -4 -needle mount being arranged to allow movement of the needle from an operative position to a shielding position; a spring means to urge movement of the needle to the shielding position; a releasable blocking means arranged to prevent movement of the needle 5 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 means allows movement of the needle to the shielding position; the needle mount is a unitary component inserted into the tubular housing and positioned so as to rotate around an axis intersecting the longitudinal axis of the tubular housing and the spring means is arranged to urge rotation of the needle about said axis; and the blocking means engages the needle mount to maintain the needle in the operative position before use, thereafter attachment of the safety needle assembly to the medical injector and the use thereof causes the blocking means to disengage from the needle mount and allow the spring means to rotate the needle to the shielding position and to move the non-patient end of the needle towards the distal end of the tubular housing 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; characterised in that; in the operative position before use, the spring means and the needle mount are arranged at a set position, thereafter use of the safety needle assembly with the medical injector causes a shift from the set position; said shift enables the spring means to rotate the needle to the shielding position when the safety needle assembly is detached from the medical injector.

Preferably the shift from the set position preloads the spring means to ensure movement of the needle to the shielding position when the safety needle assembly is detached from the medical injector.

The use of the safety needle assembly with the medical injector may comprise the attachment of the safety needle assembly to the medical injector and/or the use -5 -thereof and/or the detachment of the safety needle assembly from the medical injector.

The use of the safety needle assembly with the medical injector may cause the 5 spring means and the needle mount to move relative to one another to enable the spring means to rotate the needle to the shielding position when the safety needle assembly is detached from the medical injector.

Preferably the shift from the set position preloads the spring means to ensure movement of the needle to the shielding position (when the safety needle assembly is detached from the medical injector).

Preferably the shift from the set position causes the spring means to generate a force sufficient to urge movement of the needle to the shielding position.

Preferably the use of the safety needle assembly with the medical injector causes a change in position of the spring means relative to the needle mount.

Preferably the use of the safety needle assembly with the medical injector causes a change in position of the needle mount relative to the spring means.

Preferably the use of the safety needle assembly with the medical injector causes the spring means and the needle mount to shift apart.

Preferably the use of the safety needle assembly with the medical injector causes the spring means and the needle mount to shift closer together.

Preferably the spring means and the needle mount are arranged to shift from the set position to an active position.

Preferably in the set position, the needle mount is retained in the tubular housing with the needle in the operative position. Preferably in the set position the spring -6 -means is not fully loaded and may be unloaded. In the set position, the spring means may be partially loaded or completely unloaded.

Preferably in the active position the needle mount is retained in a pivoting position so as to be rotatable around an axis intersecting the longitudinal axis of the tubular housing and the spring means is arranged to urge rotation of the needle about said axis. Preferably in the active position the spring means is fully loaded.

The needle mount may be in the pivoting position with the spring means and needle mount in the set position.

The spring means may be arranged to be moved relative to the needle mount from the set position to an active position during attachment of the safety needle assembly to the medical injector.

The spring means may be arranged to be moved with the control member.

The needle mount may initially (in the operative position before use) be retained in a non-pivoting position prior to moving to the pivoting position. The non-pivoting position may be defined by a first pair of axial members on the tubular housing. The pivoting position may be defined by a second pair of axial members on the tubular housing. The needle mount may be arranged to move from the first pair of recesses to the second pair of recesses in order to shift the spring means and needle mount from the set position. The needle mount may comprise axial members located on an outer surface. The axial members may each provide hemispherical surfaces. The axial members may be arranged to move from the first pair of recesses to the second pair of recesses.

The axial members of the needle mount may comprise recesses and wherein the 30 needle mount may comprise axial members providing hemispherical surfaces located on an outer surface and wherein the axial members of the needle mount may be arranged to move from the first pair of recesses to the second pair of -7 -recesses.

The spring means may be mounted to the tubular housing. The spring means may comprise a leaf spring which may be in the form of a resilient finger. The leaf spring may project inwardly from an inner surface of the tubular housing. The leaf spring may project inwardly perpendicularly relative to the inner surface of the tubular housing. The leaf spring may project inwardly at an acute angle relative to the inner surface of the tubular housing.

The movement of the tubular housing relative to the needle mount may shift the spring means and needle mount from the set position and may preload the spring means.

The tubular housing may move proximally (relative to the needle mount) in order to shift the spring means and needle mount from the set position. The tubular housing may move towards the medical injector to shift the spring means and needle mount from the set position. The tubular housing may move distally (relative to the needle mount) in order to shift the spring means and needle mount from the set position.

The spring means may be mounted to a mounting member which may comprise an inner sleeve section. The movement of the mounting member relative to the needle mount may shift the spring means and needle mount from the set position. The mounting member may move proximally (relative to the needle mount) in order to shift the spring means and needle mount from the set position. The mounting member may move distally (relative to the needle mount) to shift the spring means and needle mount from the set position.

The blocking means may comprise a control member slidably displaceable along the longitudinal axis of the tubular housing from a set position. The control member may be 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 an operative position. The control member may be arranged to move -8 -away from the set position to disengage the needle mount.

The blocking means may comprise a portion of the spring means which engages with the needle mount to prevent rotational/pivotal movement of the needle mount in the set position and, preferably, with the spring in an unloaded position. A tip of the spring means (leaf spring) may locate within an indent defined on an outer surface of the needle mount. The non-pivoting position may be defined by a first pair of axial members on the tubular housing and the indent may locate in the same plane as the first pair of axial members. The depth of the indent and/or length of the resilient finger (spring means) may cause the spring means to be partially loaded in the set position. The depth of the indent and/or the (relative) length of the resilient finger (spring means) may cause the spring means to be completely unloaded in the set position.

The releasable blocking means may be arranged to prevent rotational/pivotal 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 means allows rotational/pivotal movement of the needle to the shielding position.

The spring means may comprise a leaf spring. The spring means may comprise a plastics material. The spring means may comprise a non-metal material.

An end of the leaf spring may contact an outer surface of the needle mount.

Preferably the end of the leaf spring is arranged to move along the outer surface of the needle mount as the spring means and needle mount shift from the set position.

The needle mount may comprise a flange located on an outer surface. The flange may be arranged to contact the spring means in order to transfer the spring force to 30 the needle mount.

The leaf spring may be initially spaced apart from the flange. The leaf spring may -9 -move into contact with a flange defined on the needle mount in order to shift the spring means and needle mount from the set position and preferably to an active position and may move the spring to a loaded position. The leaf spring may move into contact with a proximal surface of the flange in order to shift the spring means and needle mount from the set position and preferably to an active position and may move the spring to a loaded position. The leaf spring may move into contact with a distal surface of the flange in order to shift the spring means and needle mount from the set position and preferably to an active position and may move the spring to a loaded position.

The longitudinal axis of the tubular housing may be a central longitudinal axis of the tubular housing.

Preferably the spring means is arranged to urge rotation of needle about an axis that intersects and is perpendicular to a central longitudinal axis of the needle.

Preferably the axis of rotation is substantially radial to the longitudinal axis of the housing and/or the central longitudinal axis The control member may be located within the tubular housing or arranged to abut the proximal end of the tubular housing.

Preferably 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.

The axis of rotation may be radial with respect to the longitudinal axis of the tubular housing. The axis of rotation may be perpendicular with respect to the longitudinal axis of the tubular housing. The axis of rotation may be at an oblique angle with respect to the longitudinal axis of the tubular housing. The axis of rotation may extend across an internal diameter of the tubular housing.

-10 -The axis of rotation may intersect the central longitudinal axis of the tubular housing.

The axis of rotation may extend along a chord across the internal area of the tubular housing.

Preferably the needle mount is co-axial with the tubular housing when the needle is in the operative position.

In the shielding position, the non-patient end of the needle may contact or be adjacent to an internal peripheral wall of the tubular housing. In the shielding position, the spring means may urge the non-patient end of the needle against the internal peripheral wall of the tubular housing.

Preferably, in the operative position, the spring mean has stored energy therein.

The spring means may be mounted on (or located adjacent to) an internal wall of the tubular at a first side/portion and wherein the non-patient end of the cannula is arranged to locate adjacent to a second side/portion of the internal wall of the tubular housing. The first side/portion may be an opposite side portion provided on the tubular housing relative to the second side portion. The first side/portion may be degrees offset around the tubular housing relative to the second side/portion. The first side/portion may be longitudinally aligned with the second side/portion.

The spring means may contact the needle mount at a position located distally of the axis of rotation.

The spring means may contact the needle mount at a position located proximally of the axis of rotation.

Preferably 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. The control member may comprise an annular member and the engagement aperture is located centrally on the annular member. The needle mount may comprise a collar which locates within an aperture of the control member in the set position.

Preferably a distal end of the needle mount provides an outer surface complementary with the engagement aperture of the control member.

The control member may comprise a complementary end face with an end face of a shielding sleeve. Preferably a distal end face of the control member is complementary with a proximal end face of a shielding sleeve.

Preferably the spring means 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 and preferably applies a rotational force to rotate the needle mount.

Preferably the spring means comprises a leaf spring projecting inwardly from the tubular housing and, with the needle in an operative position, the leaf spring is in a preloaded condition and may be deflected from a neutral/relaxed position.

Preferably with the needle in the operative position the leaf spring has energy stored therein. An end surface of the leaf spring may contact an outer longitudinal surface of the needle mount to create a torque about the axis of rotation.

Preferably the needle mount comprises a unitary component having axial members located on an outer surface. The axial member may provide hemispherical surfaces and may enable the needle mount to be secured by ball and socket arrangements and may enable by a click-fit (ball and socket) arrangement. The tubular housing may comprise axial members located on an internal surface for cooperation with the axial members provided on the needle mount. Preferably the axial members of the needle mount and the tubular housing enable a push fit engagement of the needle mount into the pivoting position within the axial members of the tubular housing. The axial members of the tubular housing and the needle mount may comprise a -12 -first pair of axial member comprising projecting portions and a second pair of axial members comprising corresponding recesses. The projecting portions may comprise hemi-spherical projections. The axial members may provide a ball and socket joint. Preferably the axial members provide a first ball and socket joint on one side of the needle mount and a second ball and socket joint on an opposite side of the needle mount for connection to complementary ball and socket joints provided within the tubular housing.

Preferably the control member is mounted to move away from the proximal end (and/or towards the distal end) of the tubular housing in order to disengage the needle mount. The control member may be mounted to move towards the proximal end (and/or away from the distal end) of the tubular housing in order to disengage the needle mount.

Preferably the safety needle assembly comprises a needle shielding sleeve and, in which, the control member may comprise a distal end face of the needle shielding sleeve which provides an or the engagement aperture to prevent rotation of the needle from the operative position whilst the control member is in the set position.

The control member may comprise 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.

The control member may comprise 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 and the control member is moved from the set position on attachment of the needle safety assembly to the medical injector.

-13 -The control member may be mounted to move towards the proximal end of the tubular housing in order to disengage the needle mount. A needle shielding sleeve may encompass and shield the patient end of the needle in a non-injecting configuration and in which the needle shielding sleeve is co-axial with the tubular housing and may be arranged to slidably move longitudinally relative thereto. A needle shielding sleeve may encompass and shield the patient end of the needle in a non-injecting configuration and, in which, the needle shielding sleeve comprise release means to slidably displace the control member from the set position.

According to a second aspect of the present invention there is provided a drug delivery device comprising a safety needle assembly and a medical injector, the safety needle assembly being in accordance the first aspect of the present invention.

Preferably 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 an operative position after the control member has moved from the set position.

According to a third aspect of the present invention there is provided 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 from an operative position to a shielding position; a spring means to urge movement of the needle to the shielding position; a releasable blocking means arranged to prevent movement of the needle from the operative position whereat the needle extends in a direction along a -14 -longitudinal axis of the tubular housing and whereby release of the blocking means allows movement of the needle to the shielding position; the needle mount is a unitary component inserted into the tubular housing and positioned so as to rotate around an axis intersecting the longitudinal axis of the tubular housing and the spring means is arranged to urge rotation of the needle about said axis; and the blocking means engages the needle mount to maintain the needle in the operative position before use, thereafter attachment of the safety needle assembly to the medical injector and the use thereof causes the blocking means to disengage from the needle mount and allow the spring means to rotate the needle to the shielding position and to move the non-patient end of the needle towards the distal end of the tubular housing 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; the method being characterised by; using the safety needle assembly with the medical injector to shift the spring means and the needle mount from a set position, said shift enabling the spring means to rotate the needle to the shielding position when the safety needle assembly is detached from the medical injector, and detaching the safety needle assembly from the medical injector and rotating the needle with the spring means to the shielding position.

According to a further aspect of the present invention there is provided 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 30 needle mount being arranged to allow movement of the needle from an operative position to a shielding position; a spring means to urge movement of the needle to the shielding position; -15 -a releasable blocking means 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 means allows movement of the needle to the shielding position; the needle mount is a unitary component inserted into the tubular housing and positioned so as to rotate around an axis intersecting the longitudinal axis of the tubular housing and the spring means is arranged to urge rotation of the needle about said axis; and the blocking means engages the needle mount to maintain the needle in the operative position before use, thereafter attachment of the safety needle assembly to the medical injector and the use thereof causes the blocking means to disengage from the needle mount and allow the spring means to rotate the needle to the shielding position and to move the non-patient end of the needle towards the distal end of the tubular housing 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; characterised in that; in the operative position before use, the spring means and the needle mount are arranged at a set position and are arranged to shift from the set position; said shift enables the spring means to rotate the needle to the shielding position when the safety needle assembly is detached from the medical injector.

Preferably the spring means and the needle mount are arranged to shift from the set position to an active position. Preferably in the active position the spring means urges rotation the needle to the shielding position. Preferably in the active position the spring means rotates the needle to the shielding position when the safety needle assembly is detached from the medical injector Preferably the spring means and the needle mount are arranged to shift from the set position due to at least one of the following: the attachment of the safety needle assembly to the medical injector, the use thereof, and/or -16 -the detachment of the safety needle assembly from the medical injector.

Preferably the spring means and the needle mount are arranged to shift from the set position due to use of the safety needle assembly with a medical injector which may comprise the attachment of the safety needle assembly to the medical injector and/or the use thereof and/or the detachment of the safety needle assembly from the medical injector.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example only, with reference to the drawings that follow, in which: Figure 1 is an exploded view of an embodiment of a safety needle assembly together with a medical injector.

Figure 2 is a cutaway view of an embodiment of a safety needle assembly and a medical injector prior to attachment together.

Figure 3 is a perspective view of a tubular housing, a needle mount and a needle of an embodiment of a safety needle assembly.

Figure 4 is a perspective view of a pen injector comprising a safety needle assembly attached to a medical injector.

Figure 5 is cross section of a safety needle assembly attached to a medical injector ready to perform an injection.

Figure 6 is of a cross-section of a safety needle assembly attached to a medical injector after an injection.

Figure 7 is a cross-section of a safety needle assembly detached from a medical -17 -injector in a used configuration.

Figure 8 is a partial cut away view of a first preferred embodiment of a safety needle assembly with the spring and needle mount in the set position.

Figure 9 is a partial cut away view of a first preferred embodiment of a safety needle assembly attached to a medical injector ready to perform an injection.

Figure 10 is a partial cut away view of a first preferred embodiment of a safety needle assembly attached to a medical injector after an injection.

Figure 11 is a partial cut away view of a first preferred embodiment of a safety needle assembly detached from a medical injector in a used configuration.

Figure 12 is a partial cut away view of a second preferred embodiment of a safety needle assembly with the spring and needle mount in the set position.

Figure 13 is a partial cut away view of a second preferred embodiment of a safety needle assembly attached to a medical injector ready to perform an injection.

Figure 14 is a partial cut away view of a second preferred embodiment of a safety needle assembly attached to a medical injector after an injection.

Figure 15 is a partial cut away view of a second preferred embodiment of a safety needle assembly detached from a medical injector in a used configuration.

Figure 16 is a partial cut away view of a third preferred embodiment of a safety needle assembly with the spring and needle mount in the set position.

Figure 17 is a partial cut away view of a third preferred embodiment of a safety needle assembly attached to a medical injector ready to perform an injection.

-18 -Figure 18 is a partial cut away view of a third preferred embodiment of a safety needle assembly attached to a medical injector after an injection.

Figure 19 is a partial cut away view of a third preferred embodiment of a safety needle assembly detached from a medical injector in a used configuration.

Figure 20 is a partial cut away view of a fourth preferred embodiment of a safety needle assembly with the spring and needle mount in the set position.

Figure 21 is a partial cut away view of a fourth preferred embodiment of a safety needle assembly attached to a medical injector with the spring and needle mount in the set position Figure 22 is a partial cut away view of a fourth preferred embodiment of a safety needle assembly attached to a medical injector with the spring in a loaded position.

Figure 23 is a partial cut away view of a fourth preferred embodiment of a safety needle assembly attached to a medical injector after an injection.

Figure 24 is a partial cut away view of a fourth preferred embodiment of a safety needle assembly detached from a medical injector in a used configuration.

Figure 25 is a partial cut away view of a fifth preferred embodiment of a safety needle assembly with the spring and needle mount in the set position.

Figure 26 is a partial cut away view of a fifth preferred embodiment of a safety needle assembly attached to a medical injector with the spring and needle mount in the set position.

Figure 27 is a partial cut away view of a fifth preferred embodiment of a safety needle assembly attached to a medical injector with the spring in a loaded position.

-19 -Figure 28 is a partial cut away view of a fifth preferred embodiment of a safety needle assembly attached to a medical injector after an injection.

Figure 29 is a partial cut away view of a fifth preferred embodiment of a safety needle assembly detached from a medical injector in a used configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Throughout this specification and with reference to the figures, a safety needle assembly 10 is shown and described herein which provides for shielding of a needle 12 on a pen needle assembly 8 specifically on the non-patient (proximal) end but also, in some embodiments, also on the patient (distal) and. As used herein, the term "distal" and/or "forwards" or" forwardly", and derivatives thereof, refer to the direction generally towards the patient end for use, and the term "proximal" and/or "rearwards" or "rearwardly", and derivatives thereof, is used to describe the direction away from the patient end during use.

As shown in the figures and as will be described, the proximal end of the safety needle assembly attached to a distal end of a medical injector 11. The distal end of the safety needle assembly 10 will be pressed against the skin of patient during an injection and the distal end of the medical injector 11 locates away for the patient.

In this specification, the references to using and the use of the safety needle assembly covers the attachment of the safety needle assembly to the medical injector and/or injecting a patient and delivering the liquid medicament and/or the detachment of the safety needle assembly from the medical injector.

Throughout the following description of the preferred embodiments of safety needle assemblies of this invention, the same reference characters are used to identify 30 corresponding parts of the various embodiments.

The present invention may be used with pen injectors and will be described by way -20 -of example as being used with a pen injector. Drug delivery devices 8 generally include a medical injector 11 including a dose-adjustment mechanism for setting a dose, for example of insulin, and a pen needle 12 provided on a safety needle assembly 10 for insertion into a patient to allow proper drug administration. The pen comprises a single use needle 12 and is removed and disposed of after each administered dose.

The pen needle 12 is a double ended needle 12 and includes a patient end 14 or distal end comprising a sharp tip for insertion into a patient. The double ended needle 12 also includes a non-patient end 15 or proximal end comprising a sharp tip for insertion into a drug vial or cartridge 16 provided by the pen injector 11. The proximal/non-patient end 15 of the needle will typically have to pierce a rubber seal 18 which may comprise a septum or stopper provided on the end of the vial or cartridge 16 to access the liquid medicament or drug contained within the cartridge.

Devices have been developed in the prior art to shield the distal, or patient end of the needle 12 to prevent an inadvertent "needle stick" after use. Even with the distal end 14 being shielded, the proximal, or non-patient end 15 of the needle 12 is exposed after the detachment of the safety needle assembly 10 from the medical injector 11.

Firstly, a suitable safety needle assembly 10 will be described with reference to Figure 1 to Figure 7 following which the preferred embodiments will be described which include the spring means being movable relative to the needle mount from an unloaded position to a loaded position during attachment of the safety needle assembly to the medical injector or the use thereof.

With reference to Figure 1, a safety pen needle assembly 10 and a medical injector 11 are shown in an exploded view and Figure 4 shows the complete drug delivery device 8 in an assembled configuration. The safety needle assembly 10 generally includes a hub or tubular housing 20, a needle 12, a shielding sleeve 30. The tubular housing 20 includes a body 21 extending in a longitudinal direction from a proximal end 24 to a distal end 22 The proximal end 24 is formed with an open face open -21 -and is shaped to receive a portion of the injector 11 to allow the attachment of the safety needle assembly 10 to the injector 11. As will be described below, corresponding attachment features are provided on the tubular housing 20 adjacent to the proximal end 24 formed to cooperate with mounting features provided on a distal end of the injector 11. For example, the mounting features may be threads or a surface configuration, such as a tapered surface for a push-fit mounting, or both. The needle 12 may be of any needle design, particularly of any pen needle design. For the description of the present invention, the term cannula 12 will now be used to specifically refer to the double ended needle of the safety needle assembly 10.

The cannula 12 includes a distal end 14 formed for insertion into a patient, and a proximal end 15 for communication with a liquid medicament located in a reservoir. As shown in the figures, the distal end 14 of the cannula 12 protrudes distally beyond the distal end 22 of the tubular housing 20. The proximal end 15 of the cannula 12 may be within the interior of the tubular housing 20 adjacent to the proximal end 24, or may protrude/extend proximally from the proximal end 24 (this arrangement is not shown). The cannula 12 is mounted within a needle mount 60 and may be fixed therein using any known technique, such as being adherently fixed to the needle mount 60.

As shown in Figure 1, a drug delivery device 8 in the form of a medical pen or injector pen comprises a safety needle assembly 10 which is arranged, in use, to be attached to the medical injector 11. The medical injector 11 comprises a cartridge 16 containing a medicament/fluid and, in particular, the cartridge 16 contains a volume of liquid medicament.

The cartridge 16 is secured within a housing 17. A plunger assembly (not shown) includes a piston 19 or stopper which is used to force the liquid medicament from the cartridge 16. The cartridge 16 comprises a crimped cap 38 and a rubber seal 18. The rubber seal 18 forms a seal to contain the liquid medicament and is pierceable by a proximal end 15 of a cannula 12 (double ended needle) as will be described in more detail below.

-22 -The cartridge 16 locates within the housing 17 and the crimped cap 38 locates within a distal end of the housing 17. The distal end of the housing 17 includes a boss 40 including an aperture 33 provided on a distal end face 39 which, when assembled, aligns with the rubber seal 18 and provides an access window to the rubber seal 18 such that the rubber seal 18 is exposed and accessible through the window.

The present invention provides a safety needle assembly 10 which is attachable to the medical injector 11. The safety needle assembly 10 provides the cannula 12 through which the liquid medicament is delivered from the cartridge 16 to the patient.

The cannula 12 comprises a double ended needle having a sharp tip at the patient end (distal end) 14 and also a sharp tip at the non-patient end (proximal end) 15. However, it should be appreciated that the terms needle and cannula are used interchangeably and the present invention may also be suitable for other types of drug delivery devices 8. The present invention is suitable for use with needles or cannulas 12 and aims to prevent needle stick injuries caused by the proximal/non-patient end 15 of the needle or cannula 12.

In order to deliver the liquid medicament, the cannula 12 is held in an operative position. In this operative position, the linear cannula 12 protrudes directly out of the end of the drug delivery device 8 and, specifically, the cannula 12 extends along the (central) longitudinal axis 50 of the tubular housing 20. Accordingly, in this operative position, the cannula 12 is located in a central co-axial position within the tubular housing 20. This co-axial position enables the cannula 12 to protrude perpendicularly from a front face 31 of the needle safety assembly 10.

The safety assembly 10 provides a front face 31 having a central window or aperture 32 through which the cannula 12 projects or is projectable. In the first preferred embodiment, the safety needle assembly 10 is provided with an end cap in the form of a shielding sleeve 30 which includes the central window 32. The shielding sleeve 30 or end cap functions as a blocking means in the form of a control member 80 to retain the position of the cannula 12 and to release the cannula 12 as will be described below.

-23 -The control member 80 or shielding sleeve 30 is mounted to the tubular housing 20. The control member 80 or shielding sleeve 30 locates over the outer surface 23 of the tubular housing 20 and is retained thereto. However, control member 80 or shielding sleeve 30 is slidably movable in a longitudinal direction relative to the tubular housing 20. The significance of this longitudinal sliding movement will be described later.

The housing 17 of the injector 11 has a distal end providing an external screw thread 36 to engage with an internal screw thread 37 provided on the safety needle assembly 10. Specifically, the proximal end 24 of the tubular housing 20 provides the internal screw thread 37 for attaching the safety needle assembly 10 to the housing 17.

The cannula 12 is secured within a needle mount 60. The needle mount 60 is arranged to be fixed within the tubular housing 20 in order to secure the cannula 12 within the safety needle assembly 10. The needle mount 60 is provided with two axial members in the form of lugs 64, 65 for engagement within two corresponding axial members in the form of recesses 28, 29 provided internally on the tubular housing 20. In particular, the tubular housing 20 defines a rotational axis which may be a fixed rotational axis about which the cannula 12 is able to rotate (or pivot). Such movement is functionally important and enables the cannula 12 to rotate from an operative position to a shielding position. In the shielding position, the non-patient end 15 of the cannula 12 is shielded to prevent and/or inhibit back end needle stick injuries. As will be described, a fixed rotational axis may be provided by axle elements which are engaged within corresponding recesses to allow the rotational/pivoting action of the needle mount 60 relative to the tubular housing 20. In alternative embodiments, the rotational/pivoting functionality may be provided by a flexible section such as a live hinge arrangement whereby the rotational axis may not be statically fixed to solely provide rotation about a static rotational axis.

As will be described, the cannula 12 is arranged to rotate (or pivot) about a fixed -24 -axis 52 (or fixed point) in the tubular housing 20. In the operative position, the cannula 12 extends along the central longitudinal axis of the tubular housing 20. The fixed axis 52 for rotation extends perpendicularly and intersects the central longitudinal axis 50. The fixed axis 52 extends diametrically across the tubular housing 20 and extends radially from the central longitudinal axis 50. This creates a fixed axis 52 or fixed pivoting point or fixed point of rotation for the cannula 12 which is located on the central longitudinal axis 50.

As mentioned above, the cannula 12 is arranged to rotate about the fixed axis 52 from an operative position in which the cannula 12 extends along the central longitudinal axis 50 to a shielding position in which the cannula 12 extends at an angle to the central longitudinal axis 50. In particular, in the shielding position, the cannula 12 extends in a direction oblique to the central longitudinal axis 50.

Due to the fixed axis 52 and fixed point of rotation for the cannula 12, the movement from the central longitudinal axis 50 to an oblique position causes the non-patient end 15 of the cannula 12 to move towards the internal wall 26 of the tubular member 20. In this position with the non-patient end 15 of the cannula 12 towards and adjacent to the internal wall 26 of the tubular housing 20, the non-patient end 15 is shielded to a greater degree and provides significantly reduced risk of creating a needle stick injury. Furthermore, as a result of the fixed axis 52, the pivoting action of the needle about the fixed point located on the central longitudinal axis 50 means that the non-patient end 15 of the cannula 12 also moves forwardly On a distal direction) and away from the open end 24 of the tubular housing 20. This movement of the non-patient end 15 of the cannula 12 in a distal direction of the longitudinal axis 50 of the tubular housing 20 thereby increases the distance between the open end 24 of the tubular housing 20 and the non-patient end 15 of the cannula 12. This increases the level of protection afforded by increasing the distance by which a tip of a finger would need to be inserted into the open end 24 of the tubular housing 20 in order to make contact with the non-patient end 15 of the cannula 12. This increased separation distance coupled with the non-patient end 15 also being located adjacent to the wall 26 of the tubular housing 20 provides increased safety -25 -for users from needle stick injuries.

The increased safety arises from the arcuate or circumferential travel/movement of the non-patient end 15 of the cannula 12 as will be further described below. The passive safety system causes the cannula 12 to move from the operative position to the shielding position automatically without any specific intervention or action by the user. In particular, as is the case with normal pen injector systems, detachment of the safety needle assembly 10 from the injector 11 exposes the open end 24 of the tubular housing 20 and potentially the non-patient end 15 of the cannula 12 and thereby creates the opportunity for needle stick injuries at the back end. Accordingly, as will be described below, this system causes the cannula 12 to move to an improved shielding position automatically on detachment of the safety needle assembly 10 from the injector 11. A blocking system is arranged to retain the cannula 12 in the operative position before attachment of the safety needle assembly 10 to the medical injector 11. Furthermore, the blocking system maintains the cannula 12 in the operative position prior to use and before attachment of the safety needle assembly 10 to the injector 11. In particular, before use, the blocking system retains the non-patient end 15 in a piercing position such that the non-patient end 15 is located centrally relative to the periphery of the open end 24 of the tubular housing 20. As the injector 11 is attached to the safety needle assembly 10, the non-patient end 15 of the cannula 12 pierces the rubber seal 18 of the cartridge 16 in order to penetrate into the internal reservoir comprising the liquid medicament. Accordingly, the non-patient end 15 is located co-axially central within the tubular housing 20 in order for the tip 15 to pierce and to locate within the cartridge 16.

The use and operation of invention safety needle assembly will now be described with reference to Figure 1 to Figure 7. As described above, the drug delivery device 8 comprises the safety needle assembly 10 and the pen injector 11 and these are shown detached, prior to use, in Figure 2. In this position, the cannula 12 is held in an operative position and, specifically, the non-patient end 15 of the cannula 12 is positioned along the central longitudinal axis 50 of the tubular housing 20.

-26 -The cannula 12 is secured within the needle mount 60 which provides two axle lugs 64, 65 on opposing sides. The axle lugs 64, 65 are received within two corresponding recesses 28, 29 in the tubular housing 20 such that the cannula 12 is rotatable about a fixed axis 52 within the tubular housing 20.

The safety needle assembly 10 is attached to the pen injector 11 using the screw threads 36, 37 provided on the end of the pen injector 11 and also on the tubular housing 20. As the safety needle assembly 10 is brought into engagement with the pen injector 11 the non-patient end 15 of the cannula 12 abuts, pierces and then projects through the rubber seal 18. During this attachment, the cannula 12 is held along the central longitudinal axis 50 in order to assist with the smooth movement of the cannula 12 through the rubber seal 18.

Once attached, the non-patient end 15 of the cannula 12 locates within the central reservoir of the cartridge as shown in Figure 5.

The tubular housing 20 includes spring means in the form of a leaf spring 70 in the form of a resilient finger 72 which projects inwardly from the internal surface 26 of the tubular housing 20. The resilient finger 72 includes a contact tip 74 which contacts or abuts an outer surface of the needle mount body 62 at a position located offset from the fixed axis 52 of rotation defined by the axial members 28, 29, 64, 65. Accordingly, in the operative position, the resilient finger 72 is in a configuration whereby the tip 74 exerts a force, specifically a moment or torque, on the outer surface of the needle mount 60. Accordingly, in the operative position, the resilient finger 72 is not in a neutral position and is in a deflected state relative to the neutral relaxed condition/state/position. In particular, in the operative position, the leaf spring 70/resilient finger 72 is preloaded such that energy is stored within the leaf spring 70/resilient finger 72. This stored energy acts to urge the cannula 12 away from the operative position and away from being aligned with the longitudinal axis of the tubular housing 20. Before assembly of the needle mount 60 within the tubular housing 20, the leaf spring 70/resilient finger 72 is in a neutral state with no stored energy. On mounting of the needle mount 60 within the tubular housing 20, the leaf -27 -spring 70/resilient finger 72 is deflected and moved to store energy which acts to urge the needle mount 60 away from the operative position. On release of the cannula 12/needle mount 60 by both the control member 80 and the rubber seal 18, the non-patient end 15 of the cannula 12 locates adjacent to the internal wall 26 of the tubular housing 20. In this configuration, the leaf spring 70/resilient finger 72 would typically not be the neutral position and energy is still stored such that the leaf spring 70/ resilient finger 72 continues to press and urge the non-patient end 15 of the cannula 12 against the internal wall 26 of the tubular housing 20.

The needle mount 60 is maintained in the operative position by control means which engages a part of the needle mount 60 and maintains the cannula 12 in the operative position. In the first preferred embodiment, the blocking means is provided by the shielding sleeve 30 which includes the central aperture 32. The central aperture 32 engages around a front end of the needle mount 60. In addition, the shielding sleeve 30 is secured around the tubular housing 20 and is only able to move longitudinally with respect to the tubular housing 20 in a distal direction. Accordingly, in the set position shown in Figure 5, the front end of the needle mount 60 is secured within the aperture 32 of the shielding sleeve 30 such that any force exerted by the resilient finger 72 is counteracted and does not cause rotation of the needle mount 60 or cannula 12 about the fixed axis 52.

In this set position, it can be seen that the patient end 14 of the needle protrudes/projects outwardly from the drug delivery device 8 and is thereby able to inject a patient and to deliver the liquid medicament from the pen injector 11. Once the injection has been completed, the shielding sleeve 30 is moved forwardly to a shielding position. The specific details of the arrangement of the front shielding sleeve 30 are not provided in this specification and there are many suitable devices available, for example as described in W02011/092518. In particular, the shielding sleeve 30 slides in a distal direction longitudinally relative to the tubular housing 20, as shown in Figure 6. In this position, the needle mount 60 is no longer engaged within the aperture 32 of the shielding sleeve 30 and can no longer prevent the spring means rotating the needle mount 60 about the fixed axis 52. However, the -28 -non-patient end 15 of the cannula 12 remains engaged within the rubber seal 18 along the longitudinal axis 50 such that this arrangement still prevents rotation of the needle mount 60 about the fixed axis 52.

After use the safety needle assembly 10 requires disposal and is, therefore, detached from the medical injector 11 through use of the threaded surfaces 36, 37 to detach and unscrew the safety needle assembly 10. As shown in Figure 7, on detachment, the non-patient end 15 of the cannula 12 is withdrawn back through and disengaged from the rubber seal 18 and is therefore no longer held by the rubber seal 18 along the longitudinal axis 50 of the tubular member 20. In this configuration, there is no restraining means preventing rotation of the needle mount 60 due to the exerted torque of the resilient finger 72 and, therefore, the needle mount 60 automatically rotates about the fixed axis 52, as shown in Figure 7.

The energy stored in the resilient finger 72 rotates the needle mount 60 about the fixed axis 52 until the non-patient end 15 of the cannula 12 locates adjacent to and, preferably, abuts the internal side wall 26 of the tubular housing 20. The length of the cannula 12 ensures that the non-patient end 15 abuts the internal side wall 26. As a result of the fixed axis 52 of the needle mount 60, the non-patient end 15 of the cannula 12 moves in a distal direction and circumferentially about the axis 52 in an arcuate direction such that the distance along the longitudinal extent between the non-patient end 15 and the open face 24 of the tubular housing 20 increases. Accordingly, not only does the non-patient end 15 locate adjacent to the internal wall 26 of the tubular housing 20 but the non-patient end 15 is also withdrawn/retracted into the tubular housing 20 which significantly increases the protection afforded from needle stick injuries. Both the sideways, radial movement of the non-patient end 15 and the retraction/withdrawal movement in the distal direction of the non-patient end 15 are performed automatically and simultaneously to provide improved passive needle stick protection which requires no intervention by the user. Furthermore, in the shielding position, the leaf spring 70 may continue to exert a pivoting/rotating force on the needle mount 60 and this presses the non-patient end 15 of the cannula 12 against the internal wall 26 of the tubular housing 20.

-29 -Furthermore, it will be noted that the patient end 14 of the cannula 12 locates in a position which is not aligned with the aperture 32 of the shielding sleeve 30 such that the longitudinal sliding movement of the shielding sleeve 30 would not cause the patient end 14 of the cannula 12 to project through the aperture 32 in order to present a further risk.

Overall, the safety needle assembly 10 does not have a separate control member 80 since this functionality is provided by the needle shielding sleeve 30. Briefly, the spring 70 is arranged to urge rotation of the needle mount 60 about an axis generally perpendicular to and intersecting a longitudinal axis 50 of the cannula 12. However, the control member 80 (shown located at a first position relative to the needle mount in Figure 5) prevents rotation of the needle mount 60. As the safety needle assembly 10 (pen needle) is screwed onto the injector 11 (pen injector), the non-patient end 15 of the needle 12 pierces the rubber seal 18 of the cartridge 16 and enters into the drug reservoir within the pen injector 11. The needle shielding sleeve 30 is already retracted and in the injecting configuration and the drug can now be delivered into the patient. The pen needle 10 is removed from the injection site and the needle shielding sleeve 30 can now be moved forward and locked safely in a needle shielding position automatically. As mentioned above, the mechanism for moving the shielding sleeve is not described herein and a suitable arrangement is provided in W02011/092518. However, the needle mount 60 cannot rotate (even though the control member 80 is no longer preventing rotation of the needle mount 60) because the non-patient end 15 of the cannula 12 is still inserted into the rubber seal 18 of the pen injector reservoir. When the pen needle 10 is disconnected (detached) from the pen injector 11 the spring 70 can then rotate the needle mount 60 to "safely park" the non-patient end 15 of the cannula 12 so that the pointed end of the cannula 12 abuts against the inside wall 26 of the tubular housing 20.

The operation and use of further embodiments of suitable safety needle assemblies are shown and described in GB2104342.7 which is incorporated herein by reference.

-30 -The present invention provides an improvement on the above safety needle assembly and similar safety needle assemblies, including, but not limited to those shown in GB2104342.7.

A first embodiment of the present invention is shown in Figure 8 to Figure 11. As already described above in relation to Figure 1 to Figure 7, the safety needle assembly comprises a needle/cannula 112 mounted in a tubular housing 120. The needle has a patient end 114 and a non-patient end and an aim of the invention is to provide passive needle stick protection at the non-patient end. A further aim is to increase the reliability and to reduce fatigue on the spring means prior to use.

The cannula 112 is located within the needle mount 160 which is located within the tubular housing 120. In this embodiment, the shielding sleeve 130 provides the blocking means which retains the alignment of the cannula 110 along the longitudinal axis of the tubular member 120. In particular, the blocking means is arranged to counteract the pivoting force of the spring or an ability of the cannula to freely rotate in order to retain the cannula 112 in an operative position.

As will be described, in the present invention, the spring 170 and the needle mount are arranged at a set position and the use of the safety needle assembly 110 with the medical injector 111 causes a shift from the set position. This shift enables the spring 170 to then rotate the needle 112 to the shielding position when the safety needle assembly 110 is detached from the medical injector 111. In the first, second and third embodiments, the shift is caused by the attachment of the safety needle assembly 110 to the medical injector 111. In the fourth and fifth embodiments, the shift is caused by the use of the device i.e. the act of injecting the patient. As it will be appreciated, the shift could also be caused by the detachment (in particular, the initial part of the detachment sequence) of the safety needle assembly 110 from the medical injector 111.

Figure 8 shows the safety needle assembly 110 in an initial position with the spring -31 -and the needle mount 160 in the set position prior to attachment to the medical injector 111. The tubular housing 120 provides axial members for engaging axial members of the needle mount 160. The axial members 191a, 191b, 192a, 192b of the tubular housing 120 comprise recesses 191a, 191b, 192a, 192b and the axial members of the needle mount comprise axle lugs 164, 165. In particular, the tubular housing 120 provides a first pair of recesses 191a, 191b to mount the needle mount 160 at a first position (Figure 8) and a second pair of recesses 192a, 192b to mount the needle mount 160 at a second position (Figure 9).

The needle mount 160 is arranged to be moved relative to the spring 170 from the first (set) position to the second (active) position during the attachment of the safety needle assembly 110 to the medical injector 111. In the set position, the spring 170 may be in an unloaded position by which the spring 170 is not able to pivot the needle mount 160. For example, the spring 170 may be completely unloaded with no stored force being exerted on the needle mount 160, or the spring 170 may only be partially loaded and/or in combination with a contact position on the needle mount 160 which results in the spring 170 not being able to pivot the needle mount. In the active position, the load in the spring 170 and/or the contact position on the needle mount 160 are arranged such that the spring 170 is able to pivot the needle 112 although such movement may not actually occur until the blocking means is disengaged and/or the non-patient end 115 of the cannula 112 is extracted from the rubber seal 118.

As previously described, the safety needle assembly 110 is attached to the medical injector 111 through cooperating threaded surfaces 136, 137 or a similar arrangement. During this attachment, the non-patient end 115 of the cannula 112 pierces the rubber seal 118. This penetration eventually causes a proximal end 168 of the needle mount 160 to contact the rubber seal 118 or the area surrounding the rubber seal 118. This stops and prevents further movement of the needle mount 160 proximally relatively towards the medical injector 111.

Further engagement of the threaded surfaces 136, 137 continues the movement of -32 -the tubular housing 120 towards the medical injector 111. This movement thereby causes the tubular housing 120 to move relative to the needle mount 160 which is prevented from moving further by the end of the medical injector 111. In particular, the axle lugs 164, 165 are caused to move out of the first pair of recesses 191a, 191b and into the second pair of recesses 192a, 192b. In addition, the distal end 169 of the needle mount 160 projects into the aperture 132 of the shielding sleeve 130 to provide the blocking means.

The safety needle assembly 110 comprises spring means 170 in the form of a resilient finger 172 including a tip 174 which contacts and abuts an outer surface of the needle mount 160. In the first embodiment, the resilient finger 172 is provided on an inner surface 126 of the tubular housing 120 and projects inwardly therefrom. Accordingly, since the needle mount 160 moves relative to the tubular housing 120 during attachment, the needle mount 160 also moves relative to the resilient finger 172 during the attachment of the safety needle assembly 110 to the medical injector 111. Specifically, the point of contact between the needle mount 160 and the resilient finger 170 moves along (proximally) the outer surface of the needle mount 160 from a first contact position (Figure 8) to a second contact position (Figure 9).

As shown in Figure 8, the needle mount 160 provides a first contact position in the form of a shaped surface comprising a recess or an indent 190. In the first position, the tip 174 of the resilient finger 172 locates within this indent 196. The depth of this indent 190 may result in no or only a minimal transfer of any spring force from the resilient finger 170 to the needle mount 160. In addition, the indent 190 is located diametrically along the support axis provided by the first pair of recesses 191a, 191b. This thereby prevents the resilient finger 172 from urging the needle mount 160 to rotate relative to the tubular housing 120 when the axle lugs 164, 165 are located within the first pair of recesses 191a, 191b, as provided in the first (set) position prior to attachment. Accordingly, this prevents fatigue of the resilient finger prior to use.

In addition, the shape of the indent 190 is arranged to retain the needle mount 160 -33 -aligned with the longitudinal axis of the tubular housing 120. As shown in Figure 8, it can be seen that the needle mount 160 is prevented from rotating/pivoting by the tip 174 of the resilient finger 172. Specifically, the tip 174 will create a counter-rotational force if the needle mount 160 attempts to rotate within the tubular housing 120.

As described above, the needle mount 160 is arranged to move relative to the tubular housing 120 as the safety needle assembly 110 is attached to the medical injector 111. Specifically, a force is created through the contact of the proximal end 168 of the needle mount 160 with the distal end of the medical injector 111. This urges the needle mount forwardly relative to the tubular housing 120 and dislodges the tip 174 of the resilient finger from the indent 190. The tip 174 will then track proximally along the outer surface of the needle mount 160 until the movement is stopped and the axle lugs 164, 165 are retained in the second pair of recesses 192a, 192b in a second (active) position, as shown in Figure 9.

At this position, the resilient finger 172 creates a force on the needle mount 160. The point of contact is now offset from the diametrical axis created by the second pair of recesses 192a, 192b and this results in the resilient finger 172 creating a rotational or pivoting force on the needle mount 160. However, the distal end of the needle mount 160 now locates within the aperture 132 of the shielding sleeve 130 which thereby counteracts this rotational force and retains the cannula 112 in an operative position.

The subsequent operation of the present invention is essentially the same as that described above with reference to Figure 1 to Figure 7 and as further described in GB2104342.7. Accordingly, the present invention provides an improved safety needle assembly 110 due to the removal of any fatigue on the spring means 170 prior to attachment of the safety needle assembly 110 to the medical injector 111.

Furthermore, the activation of the spring means is automatic on attachment of the safety needle assembly 110 to the medical injector 111.

-34 -Briefly, the subsequent operation and use of the safety needle assembly 110 after attachment comprises injecting a patient following which the shielding sleeve 130 moves or is moved to an outer distal position, as shown in Figure 10. At this position, the distal end 169 of the needle mount 160 is no longer retained within the aperture 132 (blocking means) of the shielding sleeve 130. Accordingly, the engagement/penetration of the non-patient end 115 of the cannula 112 in the rubber seal 118 is the sole means for preventing the spring action of the resilient finger 172 from rotating the needle mount 160 about the axis between the second pair of recesses 192a, 192b.

The safety needle assembly 110 is then detached from the medical injector 111 through the use of the screw threads 136, 137 to the detached position shown in Figure 11. Accordingly, as the non-patient end 115 of the cannula 112 disengages and is removed from the rubber seal 118, the spring force of the resilient finger 172 automatically and immediately rotates the cannula 112 to a shielding position. In this position, the non-patient end 115 is moved to the inner surface 126 of the tubular housing 120 and is also retracted further into the tubular housing 120 away from the proximal open end 124.

A second embodiment of an improved safety needle assembly 210 is shown in Figure 12 to Figure 15. In this embodiment, the tip 274 of the resilient finger 272 initially locates distally relative to the axis through the axle lugs 264, 265 of the needle mount 260. In addition, the resilient finger 272 extends directly and radially inwardly towards the central longitudinal axis of the tubular housing 220. In the first embodiment, the resilient finger 272 does not extend directly radially inwardly but extends with an internal acute angle relative to the tubular housing 220. In the second embodiment, the resilient finger 272 forms an internal right angle with the tubular housing 220.

In this embodiment, the distal end 269 of the needle mount 260 is engaged by the shielding sleeve 230 prior to attachment of the safety needle assembly 210 to the medical injector 211 This maintains the cannula 212 aligned with the longitudinal -35 -axis of the tubular housing 220. This operative position of the cannula prevents any damage to the cannula and also maintains the non-patient end 215 in the optimum position for subsequently piercing the rubber seal 218.

The safety needle assembly 210 is attached to the medical injector 211 using the screw threads 236, 237 and this causes the proximal end 268 of the needle mount 260 to contact the distal end of the medical injector 211. Subsequent use of the threads 236, 237 causes the tubular housing 220 to keep moving proximally and the needle mount 260 moves relative thereto. This relative movement causes the axle stubs 264, 265 to dislodge/disengage from the first pair of recesses 291a, 291b.

The outer ends of the axle stubs 264, 265 are shaped to cause/aid this disengagement and the subsequent re-engagement in the second pair of recesses 292a, 292b. In particular, the outer ends of the stub axles 264, 265 are substantially hemi-spherical. As shown in Figure 13, the stub axles 264, 265 re-engage in the second pair of recesses 292a, 292b to provide an operative position for the device.

Accordingly, the attachment of the safety needle assembly 210 to the medical injector 211 causes the spring 270 and needle mount 260 to shift from the set position.

During the relative movement between the needle mount 260 to the tubular housing 220, the spring means 270 moves proximally with the tubular housing 220 relative to the needle mount 260. The needle mount 260 provides a flange 267 for engaging with the resilient finger 272. In particular, the tip 274 of the resilient finger 272 contacts and abuts a distal surface of the flange 267. This contact exerts a force on the flange 267 since the resilient finger 272 is in a deformed and loaded position when the axle stubs 264, 265 are engaged in the second pair of recesses 292a, 292b. This loading provides a rotational force for the needle mount 260 since the force is offset relative to the axis of rotation created by the pair of recesses 292a, 292b. However, the distal end 269 of the needle mount 260 is engaged in the shielding sleeve 230 and, also, the non-patient end 215 of the cannula 212 is engaged in the rubber seal 218. Accordingly, the needle mount 260 is not able to rotate but the spring means 270 is loaded. In this embodiment and in some of the -36 -other described embodiments, the spring 270 is shown to be completely unloaded in the set position. However, it should be appreciated that the spring 270 may be partially, semi-preloaded in the set position. In the set position, it is advantageous to avoid fully preloading the spring but zero or a small or a partial preloading of the spring 270 still provides the invention with the advantage of extending and prolonging the characteristics of the material of the spring 270.

The patient end 214 of the cannula 212 is ready to perform the injection. Following the injection, the shielding sleeve moves or is moved to a distal position, as shown in Figure 14. In this position, the distal end 269 of the needle mount 260 is no longer engaged with the shielding sleeve 230. However, the non-patient end 215 of the cannula 212 remains engaged in the rubber seal 218 such that the cannula 212 is still held in a position aligned with the longitudinal axis of the tubular housing 220.

The detachment of the safety needle assembly 210 from the medical injector 211 causes the non-patient end 215 to be released from the rubber seal. The loading of the resilient finger 272 then causes the needle mount 260 to rotate about the axis created between the second pair of recesses 292a, 292b. The non-patient end 215 of the cannula 212 is withdrawn into the tubular housing 220 and also moves to the inner surface 226 of the tubular housing 220 to prevent needle stick injuries.

A third embodiment of a safety needle assembly 310 is shown in Figure 16 to Figure 19. In this embodiment, the spring means 370 is again provided by an internally projecting resilient finger 372 with a tip 374. However, the resilient finger 372 is located proximally relative to the recesses 328, 329 and the axis of rotation. In the initial position, the spring means 370 is not loaded and the needle mount 360 is held in position due to the distal end 369 of the needle mount 360 being engaged in the aperture 332 of the shielding sleeve 330.

In this embodiment, the resilient finger 372 is mounted on an inner sleeve section 395 which is a separate and distinct component to the tubular housing 320. The inner sleeve section 395 locates and slides internally relative to the tubular housing -37 - 320. The inner sleeve section 395 may have an incomplete cross section and may be substantially C-shaped or may have cut out section(s) to allow for the internally projecting mount(s) for the recesses 328, 329.

In this embodiment, the resilient finger 372 moves distally from an unloaded position (set position) to a loaded position (active position). The needle mount 360 is provided with a flange 367 and the tip 374 of the resilient finger 372 is arranged to contact and create a force on a proximal surface of the flange 367. This force is offset from the axis of rotation of the needle mount 360 provided by the recesses 328, 329. This thereby urges movement of the needle 312 to the shielding position.

In use, the safety needle assembly 310 is provided detached with the spring means 370 in an unloaded position, as shown in Figure 16. The safety needle assembly 310 is attached to the medical injector 311, as shown in Figure 17. This attachment causes the spring means 370 to move distally relative to the needle mount 360 in order to load the spring means 370. Specifically, the attachment of the safety needle assembly 310 to the medical injector 311 causes the spring 370 and needle mount 360 to shift from the set position (to an active position). In particular, a proximal end 397 of the inner sleeve section 395 abuts and makes contact with a distal end of the medical injector 311 when partially attached. The inner sleeve section 395 is then prevented from moving any further towards the medical injector 311 but the further attachment moves the tubular housing 320 towards the medical injector 311. Accordingly, the tip 374 of the resilient finger 372 moves towards and abuts the flange 367 and the spring means 370 is loaded producing a rotational force on the needle mount 360.

Following the attachment and loading of the spring means 370, the injection is performed and the shielding sleeve 330 moves or is moved distally to a shielding position, as shown in Figure 18. In this position, the resilient finger 372 is urging the needle mount 360 to rotate but this is counteracted by the engagement of the non-patient end 315 with the rubber seal 318.

-38 -The subsequent detachment of the safety needle assembly 310 from the medical injector 311 releases this counteraction engagement. In particular, the non-patient end 315 is released from the rubber seal 318 and the needle mount 360 immediately rotates due to the loading of the resilient finger 372. The non-patient end 215 is withdrawn into the tubular housing 320 and locates/abuts the internal surface 326 of the tubular housing in a safe condition.

A fourth embodiment of a safety needle assembly 410 is shown in Figure 20 to Figure 24. As with the third embodiment, the resilient finger 472 is mounted on an inner sleeve section 495. However, in this embodiment, the resilient finger 472 locates distally relative to the flange 467 on the needle mount 460. In order to move the resilient finger 472 from the unloaded position to the loaded position, the resilient finger is moved proximally relative to the needle mount 460 as will be explained below.

The inner sleeve section 495 is slidably located within the tubular housing 420. The distal end 469 of the needle mount 469 engages within the aperture 432 of the shielding sleeve 430 to maintain the alignment of the cannula 412 prior to attachment with the medical injector 411. As described above, the safety needle assembly 410 is attached to the medical injector 411 and this causes tubular housing to move towards the medical injector 411. However, unlike in the earlier embodiments, this attachment does not cause the loading of the resilient finger 472. In this embodiment, the loading of the spring means is caused by the movement of the shielding sleeve 430. Specifically, the attachment of the safety needle assembly 410 to the medical injector 411 does not shift the spring 470 and needle mount 460 from the set position.

As shown in Figure 21, the cannula 412 is ready for injecting a patient with the resilient finger 472 in the unloaded position. On performing the injection, the outer distal end surface of the shielding sleeve 430 contacts the skin of the patient and as the cannula 412 is pushed further into the correct depth, the shielding sleeve 430 retracts to expose the required length of the cannula 412. The shielding sleeve 430 -39 -is moved proximally towards the medical injector 411, as shown in Figure 22.

As the shielding sleeve 430 moves proximally, the inner distal end surface of the shielding sleeve 430 contacts a distal end of the inner sleeve section 495. The 5 movement of the shielding sleeve 430 then moves the inner sleeve section 495 proximally towards the medical injector 411. In particular, the inner sleeve section 495 and the resilient finger 472 move proximally relative to the needle mount 460 which is held statically within the recesses of the tubular housing 420. Accordingly, this relative movement causes the tip 474 of the resilient finger 472 to contact the 10 flange 467 provided on the needle mount 460 in order for the spring means to be loaded. Specifically, the use and the act of injecting the patient shifts the spring 470 and needle mount 460 from the set position.

The loading exerts a rotational force on the needle mount 460. However, in this position, the needle mount 460 is maintained in an aligned position along the longitudinal axis of the tubular housing 420 since the proximal end 469 of the needle mount 460 is engaged in the aperture 432 of the shielding sleeve 430 and the cannula 412 is engaged in the rubber seal 418.

As shown in Figure 23, the shielding sleeve 430 then moves or is moved to an outer distal position which releases the distal end 469 of the needle mount 460. In this position the engagement of the cannula 412 at the non-patient end 415 solely counteracts the rotational force being exerted on the needle mount 460 by the spring means 470.

Finally, the safety needle assembly 410 is detached from the medical injector 411, as shown in Figure 24. This release the needle mount 460 and the resilient finger 472 immediately rotates the needle mount 460. This movement withdraws the non-patient end 415 into the tubular housing 420 and also positions the non-patient end 415 against the inner surface 426 of the tubular housing 420.

A fifth embodiment of the present invention is shown in Figure 25 to Figure 29. As -40 -with the fourth embodiment, the spring means 570 and needle mount 560 are maintained in the set position (with the spring in an unloaded position/inactive position) after the attachment of the safety needle assembly 510 to the medical injector 511 and it is the subsequent movement of the shielding sleeve 530 that shifts the spring 570 and needle mount 560 from the set position and activates the loading of the spring means 570. Furthermore, in this embodiment, the loading is due to the provision of two pairs of recesses 591a, 591b, 592a, 592b as will be described below.

In the initial position, as shown in Figure 25, the stub axles 564, 565 are engaged within a first pair of recesses 591a, 591b. In this position, the spring means 570 is unloaded and specifically the tip 574 of the resilient finger 572 is spaced from the flange 567. The alignment of the cannula 512 is maintained due to the engagement of the distal end 569 of the needle mount 560 with the aperture 532 of the shielding sleeve 530. As the safety needle assembly 510 is attached to the medical injector 511, the complete safety needle assembly 510 moves towards the medical injector 511. It should be noted that in this position, the proximal end 568 of the needle mount 560 is spaced for the distal end of the medical injector 511 and specifically from the rubber seal 518. As shown in Figure 26, a length of the cannula is exposed to enable the needle mount 560 to be further moved towards the medical injector 511 as explained below.

The patient end 514 is moved into the patient and the distal outer end surface of the shielding member 530 will contact the skin of the patient. The device is pressed against the skin of the patient for the cannula 512 to reach the required depth and this moves the shielding member 530 towards the medical injector 511.

In this embodiment, the needle mount 560 includes a distal collar 599. The distal collar 599 locates towards the distal end 569 of the needle mount 560. The distal collar 599 locates adjacent to the inner distal end of the shielding member 530 whilst the distal end 569 of the needle mount 560 is located in the aperture 532. The movement of the shielding sleeve 530 by the skin of the patient thereby moves the -41 -resilient finger 572 to a loaded/active position. In particular, the shielding sleeve 530 contacts and moves the distal collar 599 and hence the needle mount 560 rearwardly towards the medical injector 511. This thereby moves the flange 567 rearwardly which causes the proximal surface of the flange 567 to contact the tip 574 and to deform the resilient finger 572 into a loaded position, as shown in Figure 27. During this movement, the non-patient end 515 of the cannula 512 is moved further into the cartridge of the medical injector 511 until the proximal end 568 of the needle mount 560 abuts the medical injector 511 and, specifically, the rubber seal 518.

In this position, the spring means 570 is loaded but the needle mount 560 is restrained for rotation due to the engagement of the distal end 569 of the needle mount 560 with the aperture 532 of the shielding sleeve 530 and also the engagement of the non-patient end 515 of the cannula 512 through the rubber seal 518 As before, the shielding sleeve 530 moves or is moved to an outer shielding position, as shown in Figure 28. This releases the distal end 569 of the needle mount 560 but the cannula 512 is still engaged with the rubber seal 518 to prevent rotation of 20 the needle mount 560.

Finally, the safety needle assembly 510 is detached from the medical injector 511 which releases the cannula 512 from the rubber seal 518 and the loaded resilient finger 572 causes the needle mount 560 to immediately rotate. The rotation of the needle mount 560 causes the non-patient end 515 to withdraw into the tubular housing 520 and to locate against the inner surface 526 of the tubular housing 520.

In summary, the present invention provides a spring loading activation system for a needle mount comprising a unitary component with integral axle mounts and the tubular housing also comprises a unitary component with an integral leaf spring and axle mounts. These unitary components reduce complexity and cost and simplify assembly during manufacture. -42 -

The needle/cannula is fixedly retained in a position so as to pivot around an axis radial to the central axis of the housing. This prevents and stops proximal rearward movement of the needle mount as may occur In the present invention, spring means urges rotation of the cannula about an axis so as to move the non-patient end of the cannula distally/forwardly. Such forwards/distal movement is advantageous and reduces the chance of needle stick injuries.

A control member is located within and/or adjacent to an end of the tubular housing and is slidably displaceable along the central axis of the housing. As is shown a number of the embodiments described above, such longitudinal movement is automatic and is significantly more reliable than alternative movements within such intricate designs and a radial movement to disengage from the needle mount may be unreliable and create difficulties in assembly and manufacture.

The present invention may be incorporated and used with existing devices providing front end protection against needle stick injuries, for example as shown in 20 W02011/092518.

Overall, as described above, each embodiment comprises a movable control member to engage with a needle mount. In a set position, the needle mount is held in an operative position by the control member even though an urging torque or moment is exerted on the needle mount by a spring means. 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. The control member thereby allows the spring means to rotate the needle to the shielding position and to move the non-patient end of the needle towards the distal end of the tubular housing. In this shielding position the needle extends at an angle oblique to the central longitudinal axis of the tubular housing to place the non-patient end of the -43 -needle at a location adjacent to an interior wall of the tubular housing. The non-patient end moves along a circumferential path such that the non-patient end is retracted into or withdrawn further into the tubular housing.

An existing prior art device relating to the prevention of back needle stick injuries is shown in W02010/079016. This device includes a radially moving release part which disengages a part within which a needle is mounted. This device includes a spring which is arranged to move the shield forwardly/distally. This spring acts on the cannula to tilt the cannula and moves the cannula against a skirt. However, the spring does not retract the non-patient end of the cannula and the arrangement tends to urge the non-patient end proximally/rearwardly towards the open end of the skirt.

The present invention protects the non-patient end of a pen needle located within a tubular housing. A spring is arranged to urge rotation of the needle about an axis which either intersects a longitudinal axis of the needle or a longitudinal axis of the tubular housing which may be offset from the longitudinal axis of the needle. The spring urges and causes the needle mount to move in a direction which would retract the non-patient end of the cannula. In some embodiments the axis of rotation may be generally perpendicular to a longitudinal axis of the needle and in other embodiments the axis of rotation may be oblique to a longitudinal axis of the needle. However, a control member prevents rotation of the needle mount. As the pen needle is screwed onto to the pen injector, the non-patient end of the needle pierces the rubber seal of the cartridge and enters into the drug reservoir within the pen injector. The needle is inserted into the patient and the drug is then injected. The pen needle is subsequently removed from injection site. However, the needle mount cannot rotate (even though the control member is no longer preventing rotation of the needle mount) because the non-patient end of the needle in inserted in the rubber seal of the pen injector drug reservoir. When the pen injector is disconnected (detached) the spring can then rotate the needle mount to "safely park" the non-patient end of the needle to help prevent accidental needle stick injuries. -44 -

Claims

CLAIMS1. 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 from an operative position to a shielding position; a spring means to urge movement of the needle to the shielding position; a releasable blocking means 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 means allows movement of the needle to the shielding position; the needle mount is a unitary component inserted into the tubular housing and positioned so as to rotate around an axis intersecting the longitudinal axis of the tubular housing and the spring means is arranged to urge rotation of the needle about said axis; and the blocking means engages the needle mount to maintain the needle in the operative position before use, thereafter attachment of the safety needle assembly to the medical injector and the use thereof causes the blocking means to disengage from the needle mount and allow the spring means to rotate the needle to the shielding position and to move the non-patient end of the needle towards the distal end of the tubular housing 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; characterised in that; in the operative position before use, the spring means and the needle mount are arranged at a set position, thereafter use of the safety needle assembly with the medical injector causes a shift from the set position; said shift enables the spring means to rotate the needle to the shielding position when the safety needle -45 -assembly is detached from the medical injector.
2. A safety needle assembly according to Claim 1 in which the shift from the set position preloads the spring means to ensure movement of the needle to the shielding position when the safety needle assembly is detached from the medical injector.
3. A safety needle assembly according to Claim 1 or Claim 2 in which the use of the safety needle assembly with the medical injector causes the spring means and the needle mount to move relative to one another to enable the spring means to rotate the needle to the shielding position when the safety needle assembly is detached from the medical injector.
4. A safety needle assembly according to any preceding claim in which the shift from the set position causes the spring means to generate a force sufficient to urge movement of the needle to the shielding position.
5. A safety needle assembly according to any preceding claim in which the use of the safety needle assembly with the medical injector causes a change in position of the spring means relative to the needle mount.
6. A safety needle assembly according to any preceding claim in which the use of the safety needle assembly with the medical injector causes the spring means and the needle mount to shift apart
7. A safety needle assembly according to any one of Claim 1 to Claim 5 in which the use of the safety needle assembly with the medical injector causes the spring means and the needle mount to shift closer together.
8. A safety needle assembly according to any preceding claim in which the spring means and the needle mount are arranged to shift from the set position to an active position. -46 -
9. A safety needle assembly according to any preceding claim in which, in the set position, the spring means is partially loaded or completely unloaded.
10. A safety needle assembly according to Claim 8 in which, in the active position, the needle mount is retained in a pivoting position so as to be rotatable around an axis intersecting the longitudinal axis of the tubular housing and the spring means is arranged to urge rotation of the needle about said axis.
11. A safety needle assembly according to Claim 8 or Claim 10 in which, in the active position, the spring means is fully loaded.
12. A safety needle assembly according to any preceding claim in which the spring means is arranged to be moved with the control member.
13. A safety needle assembly according to any preceding claim in which the needle mount is initially retained in a non-pivoting position prior to moving to the pivoting position.
14. A safety needle assembly according to Claim 13 in which the non-pivoting position is defined by a first pair of axial members on the tubular housing and the pivoting position is defined by a second pair of axial members on the tubular housing.
15. A safety needle assembly according to Claim 14 in which the needle mount is arranged to move from the first pair of axial members to the second pair of axial members in order to shift the spring means and needle mount from the set position.
16. A safety needle assembly according to Claim 14 or Claim 15 in which the axial members of the needle mount comprise recesses and wherein the needle mount comprises axial members providing hemispherical surfaces located on an outer surface and wherein the axial members of the needle mount are arranged to -47 -move from the first pair of recesses to the second pair of recesses.
17. A safety needle assembly according to any preceding claim in which the spring means comprise a leaf spring which projects inwardly from an inner surface of the tubular housing.
18. A safety needle assembly according to any preceding claim in which the movement of the tubular housing relative to the needle mount causes the shift of the spring means and needle mount from the set position.
19. A safety needle assembly according to any preceding claim in which the spring means is mounted to a mounting member which comprises an inner sleeve section and wherein the movement of the mounting member relative to the needle mount causes the shift of the spring means and needle mount from the set position.
20. A safety needle assembly according to any preceding claim in which the blocking means comprises a portion of the spring means which engages with the needle mount to prevent rotational/pivotal movement of the needle mount in the set position.
21. A safety needle assembly according to any preceding claim in which a tip of the spring means locates within an indent defined on an outer surface of the needle mount.
22. A safety needle assembly according to any preceding claim in which the spring means comprises a leaf spring and an end of the leaf spring contacts an outer surface of the needle mount and wherein the end of the leaf spring is arranged to move along the outer surface of the needle mount as the spring means and needle mount shift from the set position.
23. A safety needle assembly according to any preceding claim in which the needle mount comprises a flange located on an outer surface and wherein the -48 -flange is arranged to contact the spring means in order to transfer the spring force to the needle mount.
24. A drug delivery device comprising a safety needle assembly and a medical injector, the safety needle assembly being in accordance with any one of Claim 1 to Claim 23.
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 15 needle mount being arranged to allow movement of the needle from an operative position to a shielding position; a spring means to urge movement of the needle to the shielding position; a releasable blocking means 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 means allows movement of the needle to the shielding position; the needle mount is a unitary component inserted into the tubular housing and positioned so as to rotate around an axis intersecting the longitudinal axis of the tubular housing and the spring means is arranged to urge rotation of the needle about said axis; and the blocking means engages the needle mount to maintain the needle in the operative position before use, thereafter attachment of the safety needle assembly to the medical injector and the use thereof causes the blocking means to disengage from the needle mount and allow the spring means to rotate the needle to the shielding position and to move the non-patient end of the needle towards the distal end of the tubular housing 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 -49 -a location adjacent to an interior wall of the tubular housing; the method being characterised by; using the safety needle assembly with the medical injector to shift the spring means and the needle mount from a set position, said shift enabling the spring means to rotate the needle to the shielding position when the safety needle assembly is detached from the medical injector, and detaching the safety needle assembly from the medical injector and rotating the needle with the spring means to the shielding position.