An injector device includes an elongate housing configured to receive container of medicament. The injector device also includes a needle sleeve mounted within the housing and moveable between an extended position in which the needle sleeve at least partially extends from the distal end of the housing, and a retracted position in which the needle sleeve is received further within the housing than in the extended position. The injector device also includes a release mechanism configured to control actuation of a piston rod. The release mechanism includes a rotatable member disposed within the housing and in cooperating engagement with the needle sleeve such that movement of the needle sleeve from the extended position to the retracted position causes the rotatable member to rotate within the housing from a first position to a second position.
