US Patent 8414636 Introducer with ratchet handle drive

A stent graft introducer has stent graft releasably retained onto a deployment catheter and a sheath encloses the stent graft. A handle assembly has a handle, a first slide and a second slide. The first slide retracts within the second slide and the second slide retracts within the handle. An actuation arrangement comprises a first longitudinal gear rack on the first slide, a second longitudinal gear rack on the second slide and a ratchet lever assembly on the handle. Actuation of the ratchet lever assembly causes the second slide to fully retract into the handle at which time the ratchet lever assembly engages the first gear rack through an aperture in the second rack and continued actuation causes retraction of the first slide thereby retracting the sheath from the pusher to expose the stent graft.