Patent ID: 8382710

Claim:
A syringe comprising: a barrel for containing a substance to be injected, the barrel comprising a collar at a distal end of the barrel; a needle carrier for carrying a needle fitted within a needle hub comprising an outer part which is a close fit around the outside of the collar such that the needle carrier projects into the collar, and a plunger which is adapted to be movable in the barrel to expel the substance to be injected from the needle, the plunger having a first part contained within a second part and a resilient member comprising a spring therebetween, the first and second parts being adapted to be releasably locked together by a push fit to hold said spring in a compressed state, wherein in use, the first part of the plunger and the needle carrier are adapted to engage one another following expulsion of the substance, and the second part of the plunger is adapted to be unlocked from the first part following said engagement by releasing the push fit holding, allowing said spring to expand to propel the needle carrier into the barrel, wherein the needle carrier is released from the inside of the collar under a restoring force of said spring in a direction opposite to the actuation direction of the plunger, and release of the needle carrier from the collar comprises only linear movement in said direction.