Patent ID: 8771237

Claim:
An injection device for delivering a predetermined fixed dose of liquid drug, the injection device comprising: a housing, a piston rod defining a longitudinal axis and being adapted to cooperate with a piston in causing the predetermined fixed dose to be delivered from the device, a first tubular member operatively coupled with the housing and movable to set the predetermined fixed dose, a second tubular member operatively coupled with the first tubular member and the piston rod, wherein during dose setting the first tubular member is allowed to rotate with respect to the housing from a zero dose position to a predefined dose setting stop and during injection the first tubular member is allowed to advance non-rotationally along the longitudinal axis while the second tubular member is allowed to rotate with respect to the housing, and wherein the first tubular member engages the housing via a first track and a first protruding part, one of the first track and the first protruding part being arranged on an outer surface of the first tubular member, and the other of the first track and the first protruding part being arranged on the housing, said first protruding part engaging the first track, and the second tubular member engages the first tubular member via a second track and a second protruding part, one of the second track and the second protruding part being arranged on an outer surface of the second tubular member, and the other of the second track and the second protruding part being arranged on an inner surface of the first tubular member, said second protruding part engaging the second track wherein the first track comprises a second portion which the first protruding part travels during injection of a previously set dose, and the second track comprises a second portion which the second protruding part travels during injection of a previously set dose.