A safety syringe is formed of an inner sleeve receiving a cartridge with liquid, an outer sleeve through which said inner sleeve is telescopically reciprocated, and a plunger assembly that is attached to the inner sleeve and used to eject the liquid. The needle is mounted on a front end of the inner...http://www.google.de/patents/US20050171486?utm_source=gb-gplus-sharePatent US20050171486 - Safety syringe
