Medical Needle Assembly

Abstract

A needle assembly for an injection pen ( 22 ) has a sleeve ( 21 ) supporting internally a double-ended needle having an injection end and a non-injection end ( 25 ). The end of the sleeve surrounding the non-injection end ( 25 ) of the needle is divided into deformable segments ( 28 ) and is internally threaded for interengagement with a threaded boss ( 23 ) of the injection pen ( 22 ). A collar ( 29 ) is mounted on the sleeve ( 21 ) for sliding movement between a first position where the collar ( 29 ) overlies the segmented end and maintains interengagement of the threads at that end with those of the injection pen boss ( 23 ) and a second position where the segments may expand radially to come free of the injection pen boss ( 23 ). The needle may be mounted on a carrier ( 68 ) slidable with respect to the sleeve ( 21 ), the carrier ( 68 ) being coupled to the sleeve ( 21 ) for movement thereby.

1 . A needle assembly for connection to an injection pen having a boss with external threads for receiving the needle assembly, comprising:
 a sleeve supporting internally a double-ended needle to extend axially of the sleeve, said needle having an injection end and a non-injection end and the sleeve having a radially deformable end provided with at least one internal profile for radial interengagement with the threads of the pen boss such that with full radial inter-engagement the sleeve is securely connected to the injection pen, the needle being orientated with the non-injection end directed towards said deformable end so that on connection of the sleeve to an injection pen, the non-injection end of the needle penetrates a drug reservoir within the pen;   a collar mounted around the sleeve for sliding movement between a first position adjacent the deformable end at which the collar maintains full radial inter-engagement of the profile with the threads of the boss and a second position where the collar is displaced from said end so that radial deformation of said end allows radial disengagement of the profile from the threads whereby the needle assembly may be pulled axially from the boss.   
     
     
         2 . A needle assembly as claimed in  claim 1 , wherein the internal profile is defined by an internally-threaded portion at said end of the sleeve corresponding to the external threads formed on the pen boss. 
     
     
         3 . A needle assembly as claimed in  claim 2 , wherein there is at least one generally axially-extending slit in the wall of the sleeve at said deformable end whereby the effective diameter of the deformable end may increase by enlargement of the slit. 
     
     
         4 . A needle assembly as claimed in  claim 3 , wherein there is a plurality of generally axially-extending slits in the wall of the sleeve at said deformable end thereby dividing said end into a plurality of segments. 
     
     
         5 . A needle assembly as claimed in  claim 4 , wherein each segment is provided internally with a respective profile for interengagement with the threads of the pen boss. 
     
     
         6 . A needle assembly as claimed in  claim 1 , wherein the needle is mounted on a needle hub and the needle hub is supported internally within the sleeve. 
     
     
         7 . A needle assembly as claimed in  claim 6 , wherein the needle hub is mounted within the sleeve for axial sliding movement with respect thereto. 
     
     
         8 . A needle assembly as claimed in  claim 1 , wherein there is provided a shield mounted on the sleeve for sliding movement between an injection position where the injection end of the needle is exposed and a shielding position where the injection end of the needle is covered by the shield. 
     
     
         9 . A needle assembly as claimed in  claim 8 , wherein there is provided means interconnecting the needle hub and the shield. 
     
     
         10 . A needle assembly as claimed in  claim 9 , wherein the interconnecting means serves to slide the needle hub so that the non-injection end of the needle moves deeper into the sleeve on movement of the shield to its shielding position. 
     
     
         11 . A needle assembly as claimed in  claim 10 , wherein the interconnecting means is arranged to give lost motion between movement of the shield and movement of the needle hub. 
     
     
         12 . A needle assembly as claimed in  claim 8 , wherein means are provided to lock the shield in its shielding position once moved to that position, thereby to restrain movement of the shield back towards its injection position. 
     
     
         13 . A needle assembly as claimed in  claim 8 , wherein the shield is integrated with the collar. 
     
     
         14 . A needle assembly as claimed in  claim 1 , wherein the collar is unitary with a forward section of the sleeve, the needle is supported on a hub within the forward section of the sleeve and the deformable end of the sleeve is slidably mounted with respect to the forward section such that forward movement of the collar to allow radial enlargement of the deformable end of the sleeve takes the non-injection end of the needle deeper into the sleeve, with respect to the forward end thereof. 
     
     
         15 . A needle assembly as claimed in  claim 14 , wherein means are provided to lock the deformable end of the sleeve with respect to the forward section thereof when the collar has been moved fully forwardly. 
     
     
         16 . A needle assembly for connection to an injection pen having a boss with external threads for receiving the needle assembly, comprising:
 a sleeve having internal threads at one end for threaded engagement with the external threads of an injection pen boss, the sleeve defining at least one guide extending along the length thereof;   a needle carrier slidably supported within the sleeve and having a lug engaged with the guide of the sleeve and projecting from the outer surface of the sleeve, the needle carrier supporting a double-ended needle extending axially within the sleeve; and   a shield slidably supported on the sleeve and being engaged with the projecting part of the needle carrier lug, whereby forward sliding movement of the shield moves the needle carrier forwardly within the sleeve, so moving the non-injection end of the needle further from the one end of the sleeve.   
     
     
         17 . A needle assembly as claimed in  claim 16 , wherein the shield is provided with a groove extending along the length thereof and in which the projecting part of the needle carrier lug is engaged whereby the needle carrier moves through a smaller distance than the shield, upon the shield moving from an injection position to a shielding position. 
     
     
         18 . A needle assembly as claimed in  claim 16 , wherein said one end of the sleeve is formed into two or more divided segments and a collar is mounted on the sleeve for sliding movement between a first position at which the collar maintains full radial interengagement of the segments with the external threads of the injection pen boss and a second position where the collar is displaced from said one end so that radial disengagement of the threads is possible by radial deformation of the segments at said one end. 
     
     
         19 . (canceled) 
     
     
         20 . A needle assembly as claimed in  claim 18 , wherein the internal profile is defined by an internally-threaded portion at said end of the sleeve corresponding to the external threads formed on the pen boss. 
     
     
         21 . A needle assembly as claimed in  claim 20 , wherein there is at least one generally axially-extending slit in the wall of the sleeve at said deformable end whereby the effective diameter of the deformable end may increase by enlargement of the slit. 
     
     
         22 . A needle assembly as claimed in  claim 21 , wherein there is a plurality of generally axially-extending slits in the wall of the sleeve at said deformable end thereby dividing said end into a plurality of segments. 
     
     
         23 . A needle assembly as claimed in  claim 22 , wherein each segment is provided internally with a respective profile for interengagement with the threads of the pen boss. 
     
     
         24 . A needle assembly as claimed in  claim 18 , wherein the needle is mounted on a needle hub and the needle hub is supported internally within the sleeve. 
     
     
         25 . A needle assembly as claimed in  claim 24 , wherein the needle hub is mounted within the sleeve for axial sliding movement with respect thereto. 
     
     
         26 . A needle assembly as claimed in  claim 18 , wherein there is provided a shield mounted on the sleeve for sliding movement between an injection position where the injection end of the needle is exposed and a shielding position where the injection end of the needle is covered by the shield. 
     
     
         27 . A needle assembly as claimed in  claim 26 , wherein there is provided means interconnecting the needle hub and the shield. 
     
     
         28 . A needle assembly as claimed in  claim 27 , wherein the interconnecting means serves to slide the needle hub so that the non-injection end of the needle moves deeper into the sleeve on movement of the shield to its shielding position. 
     
     
         29 . A needle assembly as claimed in  claim 28 , wherein the interconnecting means is arranged to give lost motion between movement of the shield and movement of the needle hub. 
     
     
         30 . A needle assembly as claimed in  claim 26 , wherein means are provided to lock the shield in its shielding position once moved to that position, thereby to restrain movement of the shield back towards its injection position. 
     
     
         31 . A needle assembly as claimed in  claim 26 , wherein the shield is integrated with the collar. 
     
     
         32 . A needle assembly as claimed in  claim 18 , wherein the collar is unitary with a forward section of the sleeve, the needle is supported on a hub within the forward section of the sleeve and the deformable end of the sleeve is slidably mounted with respect to the forward section such that forward movement of the collar to allow radial enlargement of the deformable end of the sleeve takes the non-injection end of the needle deeper into the sleeve, with respect to the forward end thereof. 
     
     
         33 . A needle assembly as claimed in  claim 32 , wherein means are provided to lock the deformable end of the sleeve with respect to the forward section thereof when the collar has been moved fully forwardly.