An injection device is described. A housing receives a syringe and includes areturnspring for biasing the syringe from an extended position in which its needleextends fromthe housing to a retracted position in which the it does not. A drive springacts on a firstdrive element and a second drive element acts upon the syringe to advance itfrom itsretracted position to its extended position and discharge its contents throughthe needle.The first drive element is capable of movement relative to the second once anominaldecoupling position has been reached. A release mechanism is activated whenthe firstdrive element is further advanced to a nominal release position, to releasethe syringefrom the action of the drive spring, whereupon the return spring restores thesyringe toits retracted position. The nominal decoupling and release positions aredefined relativeto the syringe. This may be achieved by interaction between a moving componentand adecoupling component that moves with the syringe as it is advanced.
