DRUG DELIVERY DEVICE WITH SHAPE MEMORY ACTUATOR, LEAD SCREW AND RATCHET MECHANISM

摘要

A drug delivery device drive (100) that includes a single shape memory alloy wire actuator (10) to advance a lead screw (14) via a ratcheting mechanism is disclosed. In one embodiment, a shape memory alloy wire (10) is operably connected to one of a pair of ratchet wheels (16, 18) and configured to drive incrementally the rotation of the connected ratchet wheel (18) via a contraction, which in turn drives the rotation of the other ratchet wheel (16) about a rotational axis (X) which moves a lead screw and advances a plunger (48) to dispense a liquid drug from a drug container (50). A drug delivery device using the shape memory alloy wire actuator in combination with the ratcheting mechanism to incrementally rotate a shaft, a lead screw or a sleeve provides for a more compact and less complicated design.