Patent ID: 8608708

Claim:
An injector apparatus for use with a cartridge ( 12 ) or syringe to deliver a plurality of doses therefrom, the injector apparatus comprising: a housing ( 10 1 , 10 2 ) for the cartridge or syringe; a plunger ( 40 ) for cooperating in use with the cartridge or syringe to express successive doses; a dose setting arrangement ( 16 , 20 ) to select a dose volume; a drive mechanism ( 22 , 24 ) releasable to advance said plunger in respective predetermined increments of magnitude to express said successive doses and in which advance of said plunger ( 40 ) is controlled by a control member ( 24 ) that moves angularly in response to an axial advance of said plunger; said dose setting arrangement including first and second complementary dose setting elements ( 16 , 20 ) threadedly engaged for relative threaded movement away from a first limit position, with said first dose setting element ( 16 ) being axially moveable relative to said housing ( 10 1 , 10 2 ) from a rest position to a dose setting position wherein said first dose setting element ( 16 ) is movable in rotation for setting the dose volume, said second dose setting element ( 20 ) being constrained to rotate with said control member ( 24 ), whereby on release of said drive mechanism by returning said first dose setting element ( 16 ) from the dose setting position to the rest position, said control member ( 24 ) and said second dose setting element ( 20 ) rotate until the second dose setting element ( 20 ) returns to said first limit position with respect to said first dose setting element ( 16 ) and prevents further rotation of the control member ( 24 ).