Injection device
First Claim
1. 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.
1 Assignment
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Accused Products
Abstract
An injection device has a drive spring which, when released, urges a loaded capsule forwards to project its needle from the end of a barrel and ejects the dose. A light return spring then retracts the needle. The drive spring acts on the capsule plunger through a drive member having a movable barrier against which the rear end of the plunger initially abuts. A first trigger releases the drive member and drive spring and after an injection a second trigger can be actuated to shift the barrier relative to the drive member and allow the return spring to act.
217 Citations
10 Claims
- 1. 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.
Specification