Patent ID: 8167849

Claim:
A drive mechanism for use in a drug delivery device is provided comprising: a housing having a proximal and a distal end; a drive member located within the said housing such that the said drive member is movable longitudinally and is non-rotatable with respect to the said housing; a piston rod that is non-rotatable with respect to the said housing and is adapted to operate through the housing and transfer a force in the longitudinal direction to the distal end of the drug delivery device; a lever operably coupled to the said piston rod and to the said drive member, said lever pivotally attached to a fulcrum of said housing wherein a) when the said drive member moves proximally with respect to the said housing the said lever pivots proximally with respect to the said piston rod; b) when the said drive member moves distally the said lever pivots distally displacing the said piston rod towards the distal end of the device.