Patent ID: 8915889

Claim:
A dispensing mechanism configured to eject successive doses of a medicament from a medicament chamber, the dispensing mechanism comprising: a housing; a dosage adjuster configured to adjust a volume of each of the successive doses of medicament; a plunger rod aligned along an axis, the plunger rod configured for ejecting the successive doses of medicament from the chamber; an actuation mechanism that comprises a trigger associated with the housing and having a ready position and a fired position with respect to the housing, the trigger being configured for manipulation by a user for successive movement in: a dosing motion from the ready position to the fired position in which the trigger is associated with the plunger rod to cause the plunger rod to eject one of the successive doses of medicament, and a resetting motion from the fired position to the ready position that comprises axial rotation of the actuation mechanism with respect to the housing, wherein the trigger is uncoupled from the plunger rod during the resetting motion; and an anti-retrograde mechanism associated with the actuation mechanism and configured to prevent movement of the actuation member in a direction opposite to an operational direction associated with each of the dosing motion and the resetting motion; wherein the anti-retrograde mechanism prevents the actuation mechanism from returning to the ready position associated with the dosing motion from the fired position associated with the dosing motion.