WO2024038285A1

WO2024038285A1 - Sensory feedback for a safety needle assembly

Info

Publication number: WO2024038285A1
Application number: PCT/GB2023/052172
Authority: WO
Inventors: Barry Peter Liversidge
Original assignee: Tip-Top.Com Ltd
Priority date: 2022-08-19
Filing date: 2023-08-18
Publication date: 2024-02-22
Also published as: GB2621631A; GB202212129D0

Abstract

The present invention provides a safety needle assembly (10) which provides tactile and/or audible sensory feedback (e.g. a click) to confirm that a pen needle is correctly fitted onto a pen injector and prevents overtightening. This secure and correct attachment is indicated when a sufficient torque load has been applied to a medical injector device (12) (pen injector). The secure attachment of a safety needle device (11) (pen needle) to the medical injector device (12) is confirmed by sensory feedback that generates tactile feedback and/or audible feedback (e.g. click). In one embodiment a rib (60) provided on a needle shielding sleeve (14) is driven beyond and past a flexible profile provided by a tab (62) provided on an outer container (70), causing the disengagement of the container (70) from the needle shielding sleeve (14) which prevents further rotation of the safety needle device (11) on to the medical injector device (12).

Description

SENSORY FEEDBACK FOR A SAFETY NEEDLE ASSEMBLY

FIELD OF THE INVENTION

The present invention relates to a safety needle assembly comprising sensory feedback and a method of providing sensory feedback for attachment of a safety needle assembly to a medical injector device.

BACKGROUND TO THE INVENTION

Safety needle devices may comprise a number of individual components retained together and provided in a sealed package for storage and delivery. During use, a user first removes a peelable seal from an outer pack and attaches the safety needle device to a medical injector device using a threaded connection or a similar arrangement and then removes the safety needle device from within the outer pack. Generally, an experienced user can gauge the amount of rotational force (torque) required to correctly attach the safety needle device to a medical injector. However, such an attachment relies on user experience and inexperienced users may overtighten or under tighten the safety needle device onto the medical injector. Either outcome is undesired, and may cause damage to the safety needle assembly and or the medical injector device, or could also result in a failure to deliver the drug satisfactorily. Accordingly, methods and arrangements for indicating a safety needle device is correctly attached to a medical injector are valuable.

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 which comprises a safety needle device and a container having a closed end and an open end to receive the safety needle device, the safety needle device 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 rotational attachment to the medical injector; a needle mount located within the tubular housing for directly or indirectly supporting a needle, a needle shielding sleeve for surrounding a supported needle and arranged coaxially with the mount so that a force applied to the sleeve slides the sleeve relative to the mount from a shielding position towards a non-shielding position whereat at least a tip of the needle extends beyond the sleeve; the needle shielding sleeve comprising retaining means to retain a relative rotational position of the needle shielding sleeve relative to the tubular housing and to allow telescopic movement of the needle shielding sleeve relative to the tubular housing; the container comprising a first engagement means on an inner surface for cooperation with a second engagement means provided on the needle shielding sleeve; wherein rotation of the container in an attachment direction relative to the tubular housing causes the first engagement means to engage the second engagement means to transfer rotational movement from the container to the needle shielding sleeve and the retaining means is arranged to transfer the rotational movement from the needle shielding sleeve to the tubular housing such that the rotation of the container attaches the safety needle device to the medical injector, and continued rotational movement generates an attachment torque which increases between the tubular housing and the medical injector until sufficient torque is generated to cause the first engagement means to disengage from the second engagement means; said disengagement allowing the container to rotate relative to the needle shielding sleeve to thereby prevent overtightening of the safety needle device onto the medical injector; and the disengagement of the engagement means generates and transmits a sensory feedback to a user to confirm the safety needle device is attached securely to the medical injector. The sensory feedback may manifest by way of audible and/or tactile sensations delivered to the user.

Preferably the proximal end of the tubular housing comprises a threaded surface arranged for screw attachment to the medical injector. Preferably the threaded surface is provided on an internal surface located at or towards the proximal end of the tubular housing.

Preferably a distal end of the medical injector comprises a threaded surface arranged for screw attachment to the tubular housing. Preferably the threaded surface is provided on an external (outer) surface located at or towards the distal end of the medical injector.

Preferably the needle mount is integral with the tubular housing for directly or indirectly supporting the needle.

Preferably the retaining means comprises a retaining member and a receiving member which prevents relative rotation between the needle shielding sleeve and the tubular housing. The retaining member may comprise a rib or a tab. The receiving member may comprise a notch or a slot. The receiving member may be on one of the needle shielding sleeve and the tubular housing and the retaining member may be on the other of the needle shielding sleeve and the tubular housing.

The needle shielding sleeve may comprise an inner shield which locates at least partially within the tubular housing and the inner shield is arranged to telescopically extend into and out from the tubular housing.

The needle shielding sleeve may comprise an outer shield which locates at least partially over the tubular housing and the outer shield is arranged to telescopically slide proximally and distally over the tubular housing. The tubular housing may comprise a rib which may be retained in a notch provided on the needle shielding sleeve.

Preferably the rib is provided on an internal surface of the tubular housing.

Preferably the notch may be provided on an outer surface of the needle shielding sleeve. The notch may be provided on a flange which may be located at a proximal end of the needle shielding sleeve.

The rib may be arranged to enable the notch to slide along the rib in order for the needle shielding sleeve to move translationally relative to the tubular housing during the telescopic movement.

The needle shielding sleeve may comprise a first notch and a second notch and the first notch may be circumferentially offset from the second notch by 180 degrees. The tubular housing may comprise a first rib and a second rib and the first rib may be circumferentially offset from the second rib by 180 degrees. Accordingly, the retaining means may comprise a first rib retained in a first notch and a second rib retained in a second notch.

The tubular housing may comprise a tab which may be retained in a slot provided on the needle shielding sleeve. Preferably the tab is provided on an outer surface of the tubular housing.

Preferably the slot comprises a linear slot which may extend from a distal end of the needle shielding sleeve towards a proximal end of the needle shielding sleeve. Preferably the slot terminates (with a closed end) prior to the proximal end of the needle shielding sleeve.

The tab may project radially out from an outer surface of the tubular housing. The tab may locate at or towards a distal end of the tubular housing. The slot may be arranged to enable the tab to move within the slot in order for the needle shielding sleeve to move translationally relative to the tubular housing during the telescopic movement.

The needle shielding sleeve may comprise a first slot and a second slot and the first slot may be circumferentially offset from the second slot by 180 degrees. The tubular housing may comprise a first tab and a second tab and the first tab may be circumferentially offset from the second tab by 180 degrees. Accordingly, the retaining means may comprise a first tab retained in a first slot and a second tab retained in a second slot.

Preferably the container comprises an outer pack.

Preferably the open end of the container is arranged to be sealed with a cover which may comprise a label. The label may comprise an adhesive label. The label may comprise a peelable label.

Preferably the first engagement means comprises a first profiled surface. Preferably the second engagement means comprises a second profiled surface.

The first profiled surface may be arranged, in use, to contact the second profiled surface and to slidably move over (and beyond) the second profiled surface. Whilst the first profiled surface is in contact with the second profiled surface the attachment torque may be (directly) transmitted from the container to the needle shielding sleeve.

The shape and/or material characteristics of the first profiled surface and/or the second profiled surface may control the maximum attachment torque that is transmittable from the container to the needle shielding sleeve.

Preferably the first engagement means comprises a tab. The tab may provide the first profiled surface. Preferably the tab comprises a flexible and/or a resilient tab. The tab may be fixed at one end to an internal surface of the container and project radially inwardly. The other end of the tab may comprise a free end. The tab may be arranged to flex towards the inner surface of the container to enable the second engagement means to ride over the tab. After the second engagement means has moved beyond the tab, the tab may be arranged to rapidly/suddenly flex away from the container back towards a neutral position and this movement may generate an audible and/or tactile sensation.

The second engagement means may comprise a raised surface or rib which may be provided on an outer surface of the needle shielding sleeve. The tab may provide the second profiled surface. The rib may comprise a linear rib which may extend from a distal end of the needle shielding sleeve towards a proximal end. Preferably the rib terminates prior to the proximal end of the needle shielding sleeve.

The needle shielding sleeve may comprise a first rib and a second rib and the first rib may be circumferentially offset from the second rib by 180 degrees. The container may comprise a first tab and a second tab and the first tab may be circumferentially offset from the second tab by 180 degrees. Accordingly, the engagement means may comprise a first tab engaging with a first rib and a second tab engaging with a second rib.

The needle shielding sleeve may comprise a plurality of circumferentially spaced ribs. The needle shielding sleeve may comprise more ribs compared to the number of tabs provided by the container.

Preferably the first engagement mean comprises an upstand which may be provided on an internal surface of the container. The upstand may provide the first profiled surface.

Preferably the upstand comprises a shaped surface. The upstand may be arranged to flex/deform the container and/or the needle shielding sleeve to enable the upstand to ride over the second profiled surface which may be provided by an edge of a slot. After the upstand has moved out of the slot, the container is then rotatable relative to the needle shielding sleeve until the upstand becomes re-engaged in the slot or engaged in another slot. Preferably movement of the upstand out of the slot generates the sensory feedback.

The second engagement means may comprise a slot which may be provided on the needle shielding sleeve. The slot may provide the second profiled surface. The slot may comprise a linear slot which may extend from a distal end of the needle shielding sleeve towards a proximal end. Preferably the slot terminates prior to the proximal end of the needle shielding sleeve.

The needle shielding sleeve may comprise a first slot and a second slot and the first slot may be circumferentially offset from the second slot by 180 degrees. The container may comprise a first upstand and a second upstand and the first upstand may be circumferentially offset from the second upstand by 180 degrees. Accordingly, the engagement means may comprise a first upstand engaging with a first slot and a second upstand engaging with a second slot.

According to a second aspect of the present invention there is provide a medical injector assembly comprising a medical injector and a safety needle assembly wherein the safety needle assembly is in accordance with the first aspect of the present invention.

According to a third aspect of the present invention there is provided a method of providing sensory feedback to indicate the secure attachment of a safety needle assembly to a medical injector, the safety needle assembly comprising: a safety needle device and a container having a closed end and an open end to receive the safety needle device, the safety needle device 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 rotational attachment to the medical injector; a needle mount located within the tubular housing for directly or indirectly supporting a needle, a needle shielding sleeve for surrounding a supported needle and arranged coaxially with the mount so that a force applied to the sleeve slides the sleeve relative to the mount from a shielding position towards a non-shielding position whereat at least a tip of the needle extends beyond the sleeve; the needle shielding sleeve comprising retaining means to retain a relative rotational position of the needle shielding sleeve relative to the tubular housing and to allow telescopic movement of the needle shielding sleeve relative to the tubular housing; the container comprising a first engagement means on an inner surface for cooperation with a second engagement means provided on the needle shielding sleeve; the method comprising: rotating the container in an attachment direction relative to the tubular housing to cause the first engagement means to engage the second engagement means to transfer rotational movement from the container to the needle shielding sleeve and the retaining means is arranged to transfer the rotational movement from the needle shielding sleeve to the tubular housing such that the rotation of the container attaches the safety needle device to the medical injector; and continuing the rotational movement of the container in the attachment direction to generate an attachment torque which increases between the tubular housing and the medical injector until sufficient torque is generated to cause the first engagement means to disengage from the second engagement means; said disengagement allowing the container to rotate relative to the needle shielding sleeve to thereby prevent overtightening of the safety needle device onto the medical injector; and the disengagement of the engagement means generates and transmits a sensory feedback to a user to confirm the safety needle device is attached securely to 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 a preferred embodiment of a medical injector device and a safety needle device in accordance with the present invention;

Figure 2 is a partial cut away view of a preferred embodiment of a medical injector device being attached to a medical injector device;

Figure 3 is a partial cut away view of a preferred embodiment of a medical injector device being attached to a medical injector device;

Figure 4 is a perspective view of another embodiment of a safety needle device in accordance with the present invention;

Figure 5 is an end view of a container of another embodiment of a safety needle device in accordance with the present invention;

Figure 6 is a perspective view of a container of another embodiment of a safety needle device in accordance with the present invention;

Figure 7 is a partial cut away view of another embodiment of a medical injector device in accordance with the present invention being attached to a medical injector device;

Figure 8 is a cross section of another embodiment of a medical injector device in accordance with the present invention being attached to a medical injector device; and Figure 9 is a perspective view of a further embodiment of a safety needle device in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A medical injector assembly comprises a medical injector device 12 (medical injector) or pen injector and a needle assembly (or safety needle assembly 10). The safety needle assembly 10 is arranged to be attached to (or connected to) the medical injector device 12. The safety needle assembly comprise a safety needle device 11 and an outer container 70. In particular, the safety needle device 11 is arranged to be connected coaxially to an end of the medical injector device 12 using cooperating connection means comprising for example threaded surfaces, or bayonet type connection, similar the fixings(fittings) used in electric light bulbs. These connection means must be sufficiently engaged to reliably and safely attach the safety needle device 11 to the medical injector device 12. However, over tightening the connection means during attachment may cause the medical injector assembly to fail to perform correctly, potentially posing a hazard or risk to a user or patient. The present invention aims to provide a reliable attachment mechanism to inform a user correct attachment has been achieved and to prevent the possibility of overtightening or under tightening the connection means.

The safety needle assembly 10 comprises a needle hub or needle mount 20, a tubular housing 30, a needle shield 1 , and an outer cover 70 or outer pack. The needle mount 20 comprises a needle 16 (cannula) mounted axially. The needle mount 20 is located within the tubular housing (and may be integral to or separate from the tubular housing) 30 which arranged to be connected to a distal end part of the medical injector device 12. In particular, the tubular housing 30 is typically arranged to be screwed onto the medical injector device 12. The distal end part of the medical injector device 12 comprises a threaded portion 15 for engagement with a corresponding threaded portion of the tubular housing 30.

The needle shield 14, tubular housing 30 and needle mount 20 together comprise a needle subassembly. The needle shield 14 comprises a needle shielding sleeve which is slidably mounted to the tubular housing 30 and is arranged to shield a distal tip/patient end 19 of the needle 16. The needle shield 14 is moveable with respect to the needle mount 20 between a first, distal position (shielded position) in which the needle shield 14 shields a distal tip of the needle 16, and a second proximal position (unshielded position) in which the distal tip of the needle 16 is exposed and extends beyond the distal end of the needle shield 14. Accordingly, the needle assembly comprises sliding engagement means to allow the needle shield 14 to slide with respect to the needle mount 20 and the tubular housing 30. Specifically, the needle shield 14 is telescopically mounted relative to the tubular housing 30.

The outer cover 70 or outer pack comprises a generally cylindrical cap and provides an open-ended container. The open end may be covered and sealed using a peelable label which is removed before use. In the sealed configuration, the safety needle device 11 is maintained in a sterile condition prior to use. During assembly of the medical injector assembly, the safety needle assembly 10 is screwed onto the medical injector device 12 by gripping an outer surface of the outer cover 70 and rotating the medical injector device 12 in the direction of the arrows indicated and shown in Fig. 2 and Fig. 3 (and as described further below). Once the safety needle device is attached to the medical injector, the outer cover 70 is then be removed prior to performing an injection.

In the present invention, the safety needle assembly 10 comprises coupling means or retaining means for rotationally coupling the tubular housing 30 and the needle shield 14. In this way, the needle shield 14 cannot be rotated with respect to the tubular housing, so that rotation of the needle shield 14 causes rotation of the tubular housing 30, as does inversely, rotation of the tubular housing causes rotation of the needle shield as described further below. This retaining means provides for a drive (coupling) mechanism whereby rotational drive is directly transmitted from one or the other of the needle shield 14 to the tubular housing 30.

The safety needle assembly 10 further comprises engagement means to act as torque transmitting means for transmitting torque (rotational force) from the outer cover 70 to the needle shield 14. Accordingly, rotation of the outer cover relative to the medical injector70 drives rotation of the needle shield 14 and thus the tubular housing 30 via the drive (coupling) mechanism. In this way, the tubular housing 30 may be screwed on to the medical injector device, as explained further below. The outer cover 70 is arranged to transmit a predetermined torque (via the torque transmitting means) to the safety needle device to screw the tubular housing 30 onto the medical injector device 12 to a predetermined tightness.

In a first embodiment, the tubular housing 30 comprises a generally tubular body and a needle 16 mounted coaxially with the tubular body on a mount 20 in an interior of the tubular body. The mount being either integral to the tubular housing or a separate component mounted within the tubular housing. The tubular housing 30 comprises a generally tubular first, proximal portion 32 and a generally tubular second, distal portion 33. The proximal and distal portion 32, 33 are fixed coaxially. The needle 16 protrudes from a distal end of the tubular housing 30. The proximal portion 32 comprises a threaded inner surface adjacent a proximal end of the tubular housing 30 and arranged to connect with a corresponding threaded distal end portion 15 of the medical injector device 12.

In this embodiment, the proximal portion 32 and/or the distal portion 33 comprises the needle mount 20 which may be a separate component which is secured therein. The needle mount 20 and a distal portion of the needle 16 extends forwardly from the distal portion, so that the needle 16 extends distally beyond the distal end of the needle mount 20.

A retaining lip 34 is provided at the distal end of the tubular body 30 and wherein the retaining lip 34 extends circumferentially around the distal end and extends radially inwards to form an annular step or shoulder in the interior. The distal portion 33 comprises rib(s) or guide rail(s) 36 which extend axially along the inner surface of the distal portion 33 of the tubular body 30. The guide rail 36 provides a retaining member for the tubular housing 30. In this preferred embodiment, there are two rails 36 which extend from the retaining lip 34 towards the proximal end. Specifically, a pair of rails 36 is provided diametrically opposed in the proximal portion 33. Each of the rails 36 is arranged to engage with part of the needle shield 14 to prevent relative rotation between needle shield and the tubular housing.

The needle shield 14 is generally tubular. An annular flange 38 is provided at a proximal end of the needle shield 14. A pair of diametrically opposed slots 37 or notches is provided in the flange 38. The slot 37/notches provide a retaining member for the needle shield 14. Each slot 37 is arranged to receive a respective one of the rails 36. A distal end of the needle shield 14 has a reduced diameter relative to the proximal end. Accordingly, a distal portion of the needle shield 14 is tapered towards the distal end. The needle shield 14 further comprises at least one engagement member for engaging the outer cover 70 which, in this embodiment, is in the form of a projecting rib 60 or lug. In this embodiment, the distal portion of the needle shield 14 is provided with a pair of diametrically opposed ribs 60. Each rib 60 projects radially outwards and extends from the distal end towards the proximal end. Each rib 60 is arranged to engage with part of the outer cover 70 so as to transmit torque from the outer cover 70 to the safety needle device and specifically to the threaded surface of the tubular housing 30.

When the safety needle assembly 10 is assembled, the needle shield 14 is disposed in the interior of the tubular housing 30. In particular, the proximal end flange 38 of the needle shield 14 is retained in the interior of the tubular housing 30 and the needle shield 14 forms an inner shield. Each slot 37 in the needle shield 14 engages with a respective rail 36 of the needle mount 20 so that the needle shield 14 is slidably retained in the tubular housing 30. With this arrangement, the needle shield 14 is arranged to slide axially in the tubular housing 30. The needle shield 14 is retained in the tubular housing 30 by the retaining lip 34 at the distal end of the tubular housing 30. The needle shield 14 is also prevented from moving proximally out of the tubular housing such that the safety needle device is a self-supporting structure and is only separable from the outer cover 70. The outer cover 70 comprises at least one torque transmitting member which is arranged to engage with and transmit torque to the safety needle subassembly. In this first embodiment, the outer cover 70 comprises an engagement member in the form of a flexible tab 62, and more specifically a pair of resiliently flexible tabs 62 arranged to resist rotational movement of the needle shield 14 within the outer cover 70. Together the flexible tabs 62 and ribs 60 comprise a means to limit the amount of torque transmitted to the safety needle assembly 10. The flexible tabs 62 are provided at the distal end of an interior of the outer cover 70. Each tab 62 extends circumferentially and radially inwards from an inner cylindrical end wall of the outer cover 70. In particular, these tabs 62 are deformable outwardly to enable the ribs 60 to rotationally pass underneath when sufficient force/torque is achieved during attachment of the safety needle assembly onto a medical pen injector.

In use, a user grips the outer cover 70 and rotates the medical injector device relative to the outer cover 70 in the direction of the arrows shown in Fig. 2 and Fig. 3. The tabs 62 each provide an abutment surface which abut a respective rib 60 on the needle shield 14, as shown in Figure 2. This contact (physically) restrains and resists rotational movement of safety needle device within the outer cover 70, effecting a resultant transference of force/torque from the outer cover 70 to the needle shield 14. The needle shield 14 is retained within the tubular housing 30 by the notches 37 and rails 36. Accordingly, the force/torque passes through the needle shield 14 as an intermediate component and is transferred to the tubular housing 30. The force/torque thereby is used with connecting the inner threads on the tubular housing 30 with the outer threads 15 on the medical injector device 12. Continued rotation of the medical injector relative to the outer cover 70 attaches the screw threads of the tubular housing 30 onto to the corresponding screw threads of the medical injector device 12.

As the threaded connection between the tubular housing and the medical injector begins to frictionally tighten, the attachment torque correspondingly increases as is normal with all conventional threaded screw connections. However, to prevent overtightening of the threaded connection and to also convey to the user a correct and secure attachment has been achieved, the present invention generates and transmits sensory feedback to the user in the form of tactile and or audible signals.

As it will be appreciated, the ribs 60 cause the flexible tabs 62 to be deflected and/or to flex in response to a corresponding frictional increase as the threaded surfaces tighten together. As is known, when screw threads “tighten-up” frictional resistance increases, and so therefore the tabs 62 gradually move radially outwards in response to the increase in resistance and eventually (when sufficient torque is applied) ride over the outermost surface of the ribs 60, as shown in Figure 3. At this resistive threshold is reached and then exceeded/surpassed, the tab(s) 62 ride over the top of the respective rib(s) 60 and thereby disengage with the ribs 60. This action results when sufficient torque is applied to the pen injector (the torque having ramped-up to a maximum peak) and then rapidly declining to a minimum, and accordingly the energy stored within the resilient flexible tabs is rapidly released allowing a part of the tabs to strike (or collide with) a part of the shield, which then generates an audible and or tactile sensation that is transmitted (conveyed) to the user as the resilient tabs flick-back inwardly to an un-deformed relaxed condition. Further additional sensory feedback will be conveyed the user, because rotational resistance (which ramped-up to a maximum peak) is then suddenly released, to allow rotation of the needle shield within the outer pack/container. This sudden change and transition from a relatively high torque resistance to little or no resistance will be “felt” and “sensed” by the user, to confirm the a correct and secure attachment has been achieved. The disengagement of the tab(s) 62 from the rib(s) 60 not only prevents a user from over tightening the threaded connection, but also ensures the safety needle device is safety secured and correctly attached to the medical injector. In this correctly attached configuration, the outer cover 70 can then be removed and the user can perform the injection.

Another preferred embodiment of the present invention is shown in Figure 4 to Figure 8. In this embodiment, the needle shield 114 comprises an outer shield. In this regard, the needle shield 114 locates over an outer surface of the tubular housing 130. The function of the needle shield 114 remains the same in that the needle shield 114 is telescopically arranged to move from a shielding position to a non-shielding position during use.

In this embodiment, the retaining means to retain the shield 114 to the tubular housing 130 comprises a lug or lugs 136 projecting outwardly from the tubular housing 130 and locate within slots 160 provided in the needle shield 114. Accordingly, this arrangement enables the needle shield 114 to move telescopically but relative rotational movement is prevented between the needle shield 114 and the tubular housing 130. This enables the attachment torque to again be transmitted through the needle shield 114 and to the tubular housing 130. As previously described, the tubular housing 130 includes an inner distal threaded surface for engagement with the threaded surface 15 provided by medical injector device 12.

The outer cover 170 and the needle shield 114 again provide engagement means to enable the attachment torque to be transmitted therebetween until a resistive torque threshold reached during attachment and whereby further rotation of the tubular housing 130 relative to the medical injector is prevented and sensory feedback in the form of an audible and or tactile sensation is provided to the user, to convey that the safety needle device has been securely attached to the medical (pen) injector. In this embodiment, the outer cover 170 includes an engagement member in the form of an inwardly projecting profile or upstand, specifically, a pair of inwardly projecting profiles spaced apart around the inner circumference by 180 degrees. Each of these profiles engages within an abutment member in the form of a corresponding slot 160 provided in the needle shield 114. Accordingly, this abutment enables the attachment torque to be transmitted from the outer cover through the needle shield 114 and to the tubular housing 130, upon rotation of the medical injector relative to the tubular housing.

As shown in Figure 8, the torque is transmitted through a profiled surface 162 and a corresponding side profile of the slot 160. As the resistance increases, the upstands 162 will move outwardly and move up and out of the slot 160 due to the resilient properties of the outer cover 170 and/or the needle shield 114. In the alternative, due to the resilient properties of the needle shield 114, the portion of the shield adjacent to the slot will flex inwardly to allow the upstand 162 to move out of the slot. As desired, this displacement of the upstand 162 from within the slot will generate and transmit sensory feedback to the user as the upstands 162 disengage with the slots 160. In this embodiment, radial inward flexing of the needle shield 114 and/or radial outward flexing of the upstands 162 within the outer cover 170 allow for the relative rotation between the tubular housing 130 and the outer cover 170 only when sufficient torque load has been applied to the medical injector device, which again, is confirmed by the sensory feedback that generates tactile and or audible feedback (in the form of a clicking sound) as the upstand profiles 162 ride out of and or fall back into the elongate slots 160 in the needle shield 114.

As in the previous embodiment, when sufficient torque is applied to the medical injector the needle shield will be “released” and allowed to rotate within the outer cover (container) which will be “sensed” and or “felt” by the user, to signify and confirm that the safety needle device is securely attached to the medical (pen) injector.

In the above embodiments, the safety needle assembly 10 may be used and function in use as previously described in US 8,968,241 and WO2015/114318. Resilient fingers (not shown and omitted for clarity) may be provided on the needle shield 114. These fingers may be attached at a distal end and the fingers may extend proximally along at least a part of the length of the slots 160. The proximal end of these fingers are arranged to slide up and over a profiled surface in order for the resilient fingers to extend and flare outwardly. Until such movement, the needle shield 114 is not movable from the outer shielding position to the inner non-shielding position. Accordingly, in the packaged state with the safety needle device located within the outer pack 170, the resilient fingers are prevented from being moved outwardly which would enable the shielding sleeve to retract. Accordingly, this arrangement prevents the safety needle device from being inadvertently activated. This could occur as the safety needle assembly is being pushed on to the medical injector device. The shielding sleeve 114 may comprise a blocking mechanism (not shown) which only allows the shielding sleeve to move once only to a non-shielding position to prevent re-use of the needle. Accordingly, a mechanism for preventing accidental movement of the needle shield 114 during attachment can be important.

A further embodiment of the present invention is shown in Figure 9. In this embodiment, the needle shield 214 is again an outer shield which is mounted over the tubular housing 230. The retaining means between the tubular housing 230 and the needle shield 214 is the same as the previous embodiment in that lugs 236 project outwardly from the tubular housing 230 and are engaged within slots 260 defined in the shield 214. The abutment means between the needle shield 230 and the outer cover 270 provides a (friction) clutch release function (similar to the other embodiments) and the needle shield 214 includes a plurality of circumferentially spaced ribs 264 extending outwardly. Each rib 264 is linear and extends from a proximal position to the distal end of the needle shield 214. The outer cover 270 may again comprise tabs or upstands projecting inwardly from an inner surface to make contact and engage with the ribs 264. The upstands and/or the ribs may comprise profiled surfaces to provide the required abutment surfaces which will (ultimately) allow the upstand profiles to pass over the ribs 264 when the desired torque release threshold is achieved during attachment of the safety needle device onto the medical injector.

In alternative embodiments, the outer cover may have inwardly projecting flutes or grooves for engaging with complementary upstanding profiles on the needle shield in the form of upstanding ribs provided on the needle shield. Alternatively, the inner surface finish of the outer cover and/or the outer surface finish of the needle shield may be textured to provide sufficient frictional resistance to prevent relative rotation between shield and pack during the connection of the safety needle device onto a medical injector, until the threshold torque limit is achieved; at which point, rotational slippage occurs between shield and pack to prevent overtightening the screw thread connection. For example, a suitable interference fit between the inner surface of the outer cover and the needle shield may provide the desired releasable engagement between the outer cover and the needle shield for the present invention.

In the present invention, the releasable engagement means between the outer container and the shield is located distally relative to the threaded surfaces.

Overall, the present invention is able to provide tactile and/or audible sensory feedback (e.g. a click) to confirm that a pen needle is correctly fitted onto a pen injector, when a sufficient torque load has been applied to a medical pen injector (which is confirmed by sensory feedback that generates tactile feedback and/or audible feedback (e.g. click) as a rib is driven beyond and past the flexible profile, causing the releasable engagement members to be disengaged.

Claims

1 . A safety needle assembly for use with a medical injector which comprises a safety needle device and a container having a closed end and an open end to receive the safety needle device, the safety needle device 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 rotational attachment to the medical injector; a needle mount located within the tubular housing for directly or indirectly supporting a needle, a needle shielding sleeve for surrounding a supported needle and arranged coaxially with the mount so that a force applied to the sleeve slides the sleeve relative to the mount from a shielding position towards a non-shielding position whereat at least a tip of the needle extends beyond the sleeve; the needle shielding sleeve comprising retaining means to retain a relative rotational position of the needle shielding sleeve relative to the tubular housing and to allow telescopic movement of the needle shielding sleeve relative to the tubular housing; the container comprising a first engagement means on an inner surface for cooperation with a second engagement means provided on the needle shielding sleeve; wherein rotation of the container in an attachment direction relative to the tubular housing causes the first engagement means to engage the second engagement means to transfer rotational movement from the container to the needle shielding sleeve and the retaining means is arranged to transfer the rotational movement from the needle shielding sleeve to the tubular housing such that the rotation of the container attaches the safety needle device to the medical injector, and continued rotational movement generates an attachment torque which increases between the tubular housing and the medical injector until sufficient torque is generated to cause the first engagement means to disengage from the second engagement means; said disengagement allowing the container to rotate relative to the needle shielding sleeve to thereby prevent overtightening of the safety needle device onto the medical injector; and the disengagement of the engagement means generates and transmits a sensory feedback to a user to confirm the safety needle device is attached securely to the medical injector.

2. A safety needle assembly according to Claim 1 in which the sensory feedback manifests by way of audible and/or tactile sensations delivered to the user.

3. A safety needle assembly according to Claim 1 or Claim 2 in which the proximal end of the tubular housing comprises a threaded surface arranged for screw attachment to the medical injector.

4. A safety needle assembly according to Claim 3 in which the threaded surface is provided on an internal surface located at or towards the proximal end of the tubular housing.

5. A safety needle assembly according to any preceding claim in which a distal end of the medical injector comprises a threaded surface arranged for screw attachment to the tubular housing.

6. A safety needle assembly according to Claim 5 in which the threaded surface is provided on an outer surface located at or towards the distal end of the medical injector.

7. A safety needle assembly according to any preceding claim in which the needle mount is integral with the tubular housing for directly or indirectly supporting the needle.

8. A safety needle assembly according to any preceding claim in which the retaining means comprises a retaining member and a receiving member which prevents relative rotation between the needle shielding sleeve and the tubular housing.

9. A safety needle assembly according to Claim 8 in which the retaining member comprises a rib or a tab.

10. A safety needle assembly according to Claim 8 or Claim 9 in which the receiving member comprises a notch or a slot.

11. A safety needle assembly according to any one of Claim 8 to Claim 10 in which the receiving member is on one of the needle shielding sleeve and the tubular housing and the retaining member is on the other of the needle shielding sleeve and the tubular housing.

12. A safety needle assembly according to any preceding claim in which the needle shielding sleeve comprises an inner shield which locates at least partially within the tubular housing and the inner shield is arranged to telescopically extend into and out from the tubular housing.

13. A safety needle assembly according to any one of Claim 1 to Claim 11 in which the needle shielding sleeve comprises an outer shield which locates at least partially over the tubular housing and the outer shield is arranged to telescopically slide proximally and distally over the tubular housing.

14. A safety needle assembly according to any preceding claim in which the tubular housing comprises a rib which is retained in a notch provided on the needle shielding sleeve, the rib being provided on an internal surface of the tubular housing and the notch being provided on an outer surface of the needle shielding sleeve.

15. A safety needle assembly according to Claim 14 in which the rib is arranged to enable the notch to slide along the rib in order for the needle shielding sleeve to move translationally relative to the tubular housing during the telescopic movement.

16. A safety needle assembly according to any one of Claim 1 to Claim 13 in which the tubular housing comprises a tab which is retained in a slot provided on the needle shielding sleeve, the tab being provided on an outer surface of the tubular housing and the slot comprising a linear slot which extends from a distal end of the needle shielding sleeve towards a proximal end of the needle shielding sleeve.

17. A safety needle assembly according to Claim 16 in which the slot is arranged to enable the tab to move within the slot in order for the needle shielding sleeve to move translationally relative to the tubular housing during the telescopic movement.

18. A safety needle assembly according to any preceding claim in which the open end of the container is arranged to be sealed with a cover which may comprise a label.

19. A safety needle assembly according to any preceding claim in which the first engagement means comprises a first profiled surface and the second engagement means comprises a second profiled surface and wherein the first profiled surface is arranged, in use, to contact the second profiled surface and to slidably move over and beyond the second profiled surface and whilst the first profiled surface is in contact with the second profiled surface the attachment torque is directly transmitted from the container to the needle shielding sleeve.

20. A safety needle assembly according to any preceding claim in which the first engagement means comprises a tab and wherein the tab comprises a flexible tab which is fixed at one end to an internal surface of the container and projects radially inwardly.

21 . A safety needle assembly according to Claim 20 in which the other end of the tab comprises a free end and the tab is arranged to flex towards the inner surface of the container to enable the second engagement means to ride over the tab, after the second engagement means has moved beyond the tab, the tab is arranged to rapidly flex away from the container back towards a neutral position and this movement generates an audible and/or tactile sensation.

22. A safety needle assembly according to any preceding claim in which the second engagement means comprises a rib which is provided on an outer surface of the needle shielding sleeve.

23. A safety needle assembly according to any preceding claim in which the first engagement mean comprises an upstand which is provided on an internal surface of the container and wherein the upstand is arranged to flex or deform the container and/or the needle shielding sleeve to enable the upstand to ride over a profiled surface which is provided by an edge of a slot provided on the needle shielding sleeve.

24. A medical injector assembly comprising a medical injector and a safety needle assembly wherein the safety needle assembly is in accordance with any one of Claim 1 to Claim 23.

25. A method of providing sensory feedback to indicate the secure attachment of a safety needle assembly to a medical injector, the safety needle assembly comprising: a safety needle device and a container having a closed end and an open end to receive the safety needle device, the safety needle device 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 rotational attachment to the medical injector; a needle mount located within the tubular housing for directly or indirectly supporting a needle, a needle shielding sleeve for surrounding a supported needle and arranged coaxially with the mount so that a force applied to the sleeve slides the sleeve relative to the mount from a shielding position towards a non-shielding position whereat at least a tip of the needle extends beyond the sleeve; the needle shielding sleeve comprising retaining means to retain a relative rotational position of the needle shielding sleeve relative to the tubular housing and to allow telescopic movement of the needle shielding sleeve relative to the tubular housing; the container comprising a first engagement means on an inner surface for cooperation with a second engagement means provided on the needle shielding sleeve; the method comprising: rotating the container in an attachment direction relative to the tubular housing to cause the first engagement means to engage the second engagement means to transfer rotational movement from the container to the needle shielding sleeve and the retaining means is arranged to transfer the rotational movement from the needle shielding sleeve to the tubular housing such that the rotation of the container attaches the safety needle device to the medical injector; and continuing the rotational movement of the container in the attachment direction to generate an attachment torque which increases between the tubular housing and the medical injector until sufficient torque is generated to cause the first engagement means to disengage from the second engagement means; said disengagement allowing the container to rotate relative to the needle shielding sleeve to thereby prevent overtightening of the safety needle device onto the medical injector; and the disengagement of the engagement means generates and transmits a sensory feedback to a user to confirm the safety needle device is attached securely to the medical injector.