Patent ID: 6159181
Filing Date: 2000-12-12
Classification: A61M

Abstract:
A one-shot injection device with a barrel-like body carrying a loaded capsule having a needle at its forward end and a spring drive system which, when released, drives the capsule forwards to project the needle from the body and eject a dose through the needle, and which thereafter can cause the capsule and needle to be retracted, wherein the spring drive system comprises a drive spring, a hollow drive member acted upon by the drive spring and initially held in a rearward position by a first trigger, an abutment member between the drive member and the rear end of the plunger whose forward end forms or acts upon a piston within the capsule, a return spring acting between the capsule and the body, and a second trigger operable when the drive member is in a forward position to move the abutment member from an engaged position in relation to the drive member to a disengaged position where the return spring can act to push the abutment member rearwardly via the capsule and its plunger, thereby retracting the needle.