Patent ID: 6716197
Filing Date: 2004-04-06
Classification: A61M

Abstract:
A needle retracting mechanism (1) for a hypodermic syringe (2), comprising a body (3) with a needle retraction chamber (4), which body (3) in a first end (5) is adapted to receive injectant from a syringe barrel (7) and in a second end (6) slidingly supports a needle (27) which by means of a force from a pretensioned actuator (8) is retractable into the needle retraction chamber (4), the actuator (8) being releasable by response to the injectant, characterised in comprisinga funnel-shaped entrance opening (18) to the needle retraction chamber (4), a retainer (9) for the actuator (8) and the needle (27), the retainer (9) comprises a compressible portion (10) which in a retaining position is bigger than the entrance opening (18) and abuts funnel-shaped sides (16) of the entrance opening (18), and in a compressed release position is smaller than the entrance opening (18) and can enter the needle retraction chamber (4) together with the needle (27), the pretensioned actuator (8) forces the retainer (9) into the funnel-shaped entrance opening (18), forcing the compressible portion (10) towards the release position, a spacer (11) for keeping the compressible portion (10) in the retaining position, made from a material which after some time in contact with the injectant loses its mechanical strength, whereupon a contact between the spacer (11) and the injectant causes the spacer (11) to lose its mechanical strength, the actuator (8) forces the compressible portion (10) into the release position and into the entrance opening (18), causing the retainer (9) and needle (27) to enter the needle retraction chamber (4).