Patent ID: 8177749

Claim:
A system for injecting a fluid medicament into a patient, the system comprising: a drive mechanism; a hypodermic syringe pre-filled with the fluid medicament; and a cassette for receiving and holding the hypodermic syringe; wherein the drive mechanism comprises a cradle, a first motor, and a second motor; wherein the syringe comprises a needle, and a stopper for expelling the medicament from the syringe through the needle; wherein the first motor of the drive mechanism is for moving the syringe in the cassette between a first position and a second position when the cassette is mounted in the cradle of the drive mechanism, the first position being a proximal position for hiding the syringe needle inside the cassette, and the second position being a distal position where the needle extends from the cassette for injection of the medicament; wherein the second motor is for pushing the stopper to expel the medicament from the syringe while the syringe is in the distal position; and wherein the cassette comprises: an inner sleeve for holding the syringe an outer sleeve comprising a hollow tube having a wall defining an axis, and having a first end and a second end, with the wall of the tube having a longitudinal slot extending between the first and second ends of the tube, the outer sleeve for supporting the inner sleeve during movement of the inner sleeve thereon between the proximal position and the distal position, with the inner sleeve being selectively engaged with the outer sleeve to firmly hold the inner sleeve in the proximal position, and engageable with the first motor of the drive mechanism for release of the inner sleeve from the outer sleeve and subsequent movement of the syringe with the inner sleeve between the proximal position and the distal position; a resilient arm formed on the wall of the outer sleeve with a detent formed on the arm, the arm being biased to extend the detent into the slot of the outer sleeve; and a projection extending radially outward from the inner sleeve and into the slot of the outer sleeve for selective engagement with the detent of the outer sleeve.