Patent ID: 7717874

Claim:
A needle-free injection device, comprising: a piston configured to be advanced during delivery of an injection; a gas cartridge disposed within a gas cartridge housing and movable relative to the gas cartridge housing from an initial position to an actuating position, in which a pierceable sealed opening at a forward end of the gas cartridge is pierced by a piercing member to enable pressurized gas to be released from the gas cartridge to act upon a rearward end of the piston, thereby driving the piston forward to forcibly expel injectable fluid out through an injection orifice; and a recoil inhibiter configured to constrain movement of the gas cartridge after delivery of the injection so that the gas cartridge is movable from the initial position to the actuating position during delivery of the injection, but is prevented from moving from the actuating position back to the initial position after delivery of the injection is complete; wherein the recoil inhibitor includes a ratchet structure that is formed in an elongate slot, and where a pawl device includes a resilient leg that ratchets against an edge of the elongate slot as the pawl device is moved forward relative to the gas cartridge housing.