Patent ID: 9440029
Filing Date: 2016-09-13
CPC Classification: A61M

Claim Text:
1. A drive mechanism for a drug delivery device, comprising: a lead screw and a lead screw nut aligned with an axis defining an axial direction, and an opposite axial direction, and radial directions diverging from the axis, the lead screw comprising (i) a screw thread and (ii) at least one further screw thread, the screw thread and the at least one further screw thread having the same pitch and being intertwined, and a drive feature of the lead screw nut, the drive feature comprising three angularly equi-spaced drive portions; the drive feature engaging the screw thread and the further screw thread and allowing for a dispense operation of a fixed dose, the dispense operation comprising a helical movement of the lead screw with respect to the lead screw nut at least in the axial direction, the lead screw advancing a piston in a distal direction.