Patent ID: 8915888
Filing Date: 2014-12-23
Classification: A61M,Y10T

Abstract:
1. A drive mechanism for use in a drug delivery device comprising: a housing having a proximal and distal end; a drive sleeve non-rotatable with respect to said housing; a piston rod engaged with the said drive sleeve optionally by engagement means; wherein the said piston rod further comprises a distal helical thread portion threadedly engaged with the said housing and a means located at the proximal end of the said piston rod for releasable engagement to the said drive sleeve; characterized in that, a) when the said drive sleeve moves proximally without rotating with respect to the said housing the said piston rod does not move with respect to the said housing; b) when the said drive sleeve moves distally the said piston rod rotates with respect to the said housing so that a force is transferred in the longitudinal direction to the distal end of the said drug delivery device.