Patent ID: 8226631
Filing Date: 2012-07-24
Classification: A61M,Y10T

Abstract:
1. A drive mechanism for use in a drug delivery device, the drive mechanism comprising: a housing having an internal helical thread; an activation member that is non-rotatable with respect to the said housing; a drive sleeve engaged with the said housing; a piston rod comprising a distal threaded portion and a proximal threaded portion characterized in that, a) the distal threaded portion of the said piston rod is threadedly engaged with the said housing; b) the proximal threaded portion of the said piston rod is threadedly engaged with the drive sleeve; such that, c) when the said activation member moves proximally with respect to the said housing, the said drive sleeve rotates with respect to the said activation member and moves proximally with respect to the said housing; d) when the said activation member moves distally with respect to the said housing, the said drive sleeve (i) moves distally with respect to the said housing and (ii) is prevented from rotating with respect to the said housing, and the said piston rod is caused to rotate with respect to the said housing so that a force is transferred in the longitudinal direction to a distal end of the drug delivery device.