A hypodermic needle assembly configured such that the movement of a needle shield into position to block the needle tip occurs as a direct consequence of a longitudinal force applied by insertion of a syringe plunger is provided. The hypodermic needle assembly according to the present invention comprises...http://www.google.co.uk/patents/US20060264828?utm_source=gb-gplus-sharePatent US20060264828 - Spring launched needle safety clip
