US Patent 7300423 Safety device with trigger mechanism

A safety device, usable in particular with hypodermic needles, and incorporating a trigger mechanism which when activated primes the device to initiate the unsheathing of the needle in use by flexing one or more needle-surrounding legs away from the needle axis; the initial priming and leg-flexing movement being caused by the interaction of an operative portion of the trigger with the or each said leg or with a member connected operatively thereto; characterised by the feature that, when such movement occurs, the trigger end interacts with the leg or the said, part connected thereto in a manner which positively latches and retains the two in engagement.