Patent ID: 6800071
Filing Date: 2004-10-05
Classification: A61M,Y10S

Abstract:
An apparatus for dispensing a medication fluid comprising:a reservoir adapted to contain the fluid and adapted for use with a drive system having a threaded linear actuation member; and a piston comprising: a first member adapted to be slidably mounted within the reservoir and adapted to form a fluid-tight barrier within the reservoir; the first member having an external proximate side and an external distal side, the external proximate side being adapted to contact the fluid and being made of a material having a first stiffness, the external distal side including threads adapted to releasably engage the threaded linear actuation member; a second member having a first side and a second side, the first side and the second side of the second member being entirely contained within the first member and being adapted not to contact the fluid; and the first side of the second member being adjacent to the external proximate side of the first member and being made of a material having a stiffness which is greater than the first stiffness.