NEEDLE MOUNTING ASSEMBLY FOR A MEDICATION INJECTION DEVICE

摘要

A needle mounting assembly for mounting a pen needle in fluid communication with a medication cartridge. In one form the needle mounting assembly includes a collet and a stop collar. The collet defines an opening in which is slidably fittable the outlet end of the cartridge, and the collet is shiftable relative to the cartridge outlet end between a first axial position and a second axial position. The collet includes a base and a plurality of fingers that are forward of the base. The stop collar is one of axially secured to and integrally formed with one of the cartridge and a retainer for the cartridge. The stop collar is adapted to halt movement of the collet at the first axial position when the collet moves from the second axial position. When the collet is disposed in the first axial position, the plurality of resilient fingers extend forward of the cartridge outlet end and are disposed in a first radial arrangement in which a needle hub of the pen needle can be freely axially placed onto and freely axially removed from the plurality of resilient fingers. When the collet is moved to the second position from the first position when the needle hub is freely placed onto the plurality of resilient fingers, the plurality of resilient fingers are shifted by engagement with the cartridge outlet end to a second radial arrangement to operationally secure the needle hub for medication delivery with a tip of a cannula of the pen needle piercing the cartridge septum. When the collet at the second position with the needle hub operationally secured by the plurality of outlet fingers is moved to the first position, the tip of the cannula of the pen needle is withdrawn from the cartridge septum and the plurality of resilient fingers shift back to the first radial arrangement for free axial removal of the needle hub from the mounting assembly.