Patent ID: 8221097
Filing Date: 2012-07-17
Classification: A61M,F04B

Abstract:
1. An actuator mechanism for a hermetically sealed implantable fluid infusion device having a piston channel, a first fluid chamber above the piston channel, and a second fluid chamber below the piston channel, the actuator mechanism comprising: an armature that moves between a forward position and a retracted position to facilitate delivery of fluid from the first fluid chamber to the second fluid chamber via the piston channel; a piston coupled to the armature and positioned within the piston channel, the piston having an outer surface facing an inner wall of the piston channel, an inlet end in fluid communication with the first fluid chamber, and an outlet end in fluid communication with the second fluid chamber, and the piston being moveable within the piston channel; at least one groove formed in the outer surface of the piston from the inlet end of the piston to the outlet end of the piston, the at least one groove forming a first flow path to conduct fluid between the first fluid chamber and the second fluid chamber; and an annulus defined between the outer surface of the piston and the inner wall of the piston channel, the annulus forming a second flow path to conduct fluid between the first fluid chamber and the second fluid chamber; wherein the at least one groove comprises a helical groove around the piston.