Patent ID: 9731079
Date: 2017-08-15
CPC Classifications: A61M

Claim:
1. A drive assembly for use in a medication delivery device, comprising: a housing having a proximal end and a distal end, a drive member moveable in a proximal direction with respect to the housing for setting a dose of the medication to be delivered and in a distal direction with respect to the housing for delivering the dose, a piston rod adapted to be driven by the drive member in the distal direction with respect to the housing during movement of the drive member in the distal direction for delivering the dose, wherein the piston rod includes at least one indentation disposed along an exterior peripheral surface of the piston rod and configured as a stop feature, and a restriction member protruding radially inward from the housing and configured to interact mechanically with the stop feature of the piston rod for restricting a proximal movement of the piston rod with respect to the housing during a proximal movement of the drive member, wherein the restriction member and the stop feature are arranged for the piston rod to be moved proximally a first distance during a first proximal movement of the drive member before the restriction member and the stop feature interact mechanically, wherein the first distance which the piston rod moves proximally during the first proximal movement of the drive member is larger than a subsequent distance which the piston rod moves proximally during a subsequent proximal movement of the drive member, and wherein the piston rod comprises a plurality of stop features, the drive assembly being configured for the restriction member to mechanically interact with a different stop feature after distal movement of the drive member for dose delivery.