Patent ID: 6375638
Filing Date: 2002-04-23
Classification: A61M

Abstract:
A drive mechanism for a medication delivery device, the drive mechanism comprising:a force receiving member; a force applying member operatively coupled to the force receiving member to cause relative movement to occur between the force receiving member and the force applying member so that the force receiving member is in a different position relative to the force applying member; and a shape memory actuator formed from a shape memory material and which is operatively coupled to the force applying member, and wherein the shape memory actuator is heat activated to distort the shape memory actuator from a first shape to a second shape to activate the force applying member to act upon the force receiving member to cause the relative movement between the force applying member and the force receiving member so that the force receiving member is in the different position relative to the force applying member, and wherein the shape memory actuator is returned to the first shape from the second shape after the force receiving member is in the different position relative to the force applying member; wherein the force receiving member is a guide and the force applying member is a carriage assembly, and wherein the guide is a shaft and the carriage assembly includes at least one pawl, a lever and a cam surface on one end of the lever, and wherein the shape memory actuator is coupled to another end of the lever and actuated to move the cam surface of the lever against the at least one pawl to incrementally move the carriage assembly relative to the shaft.