Patent ID: 7169132

Claim:
A medication delivery pen having a cartridge containing a predetermined amount of medication for injection into a patient, the cartridge having a plunger axially movable therein to expel the medication from the cartridge, said medication delivery pen comprising: a lead screw having an enlarged portion at a first end thereof, said lead screw having an end longitudinally opposite said first end in contacting engagement with the plunger, said lead screw being selectively axially displaceable by a user when selectively administering a predetermined dosage amount of medication for injection into a patient; a driver coaxially disposed about said lead screw; and a reset ring non-rotatably disposed on said driver and axially slidable thereon and therealong, said reset ring being axially movable with respect to said driver and said lead screw when a dosage amount is set by a user of said medication delivery pen, wherein said reset ring includes at least one protrusion which engages said enlarged portion of said lead screw upon a predetermined extent of relative axial movement between said reset ring and said lead screw.