A syringe device for cartridged drugs has automatic needle retraction after cartridge contents expression. A drug cartridge is at least partially accommodated within a hollow piston actuator or carrier and is released for further retraction under bias thereinto by way of a piston rod. The piston rod...http://www.google.fr/patents/US5487732?utm_source=gb-gplus-shareBrevet US5487732 - Syringe with retractable needle
