Patent ID: 7967795

Claim:
A combination cartridge and cartridge interface assembly comprising: a rotationally immobile cartridge having an inner cylindrical surface, a first stopper slidingly inserted in the cartridge, a distal end and a substance therein for administration to a subject; a cartridge interface assembly comprising: a driving plunger comprising a first shaft; and a driver comprising a second shaft, said second shaft mating with said first shaft, so that said shafts are movable telescopically with respect to one another, wherein rotation of said driver causes said driving plunger to linearly advance in a direction away from said driver, the arrangement being such that on insertion of the cartridge interface assembly in the rotationally immobile cartridge, the driving plunger is in complementary anti-rotation friction relation with the inner cylindrical surface, said complementary anti-rotation friction relation being the only force impeding rotation of the driving plunger with respect to the cartridge such that rotation of said driver causes said driving plunger to linearly advance only towards the distal end until the driving plunger abuts against the stopper whereupon the driving plunger urges the stopper towards the distal end for metering substance from the cartridge.