Surgical stapling instrument incorporating an uneven multistroke firing mechanism having a rotary transmission

Abstract From the Canadian patent

A surgical stapling and severing instrument particularly suited to endoscopic procedures incorporates a handle that produces separate closing and firing motions to actuate an end effector. In particular the handle produces multiple firing strokes in order to reduce the required amount of force required to fire (i.e. staple and sever) the end effector. Varying the center of rotation circumferential length, and depth of cam lobes in a cam disk that interacts with the firing trigger via a drive wedge allows optimization. In particular mechanical advantages during specific firing strokes mitigates increased force to fire at the end effector enabling a more uniform tactile force at the firing …