Abstract: A surgical instrument for laparoscopic and endoscopic clinical procedures simultaneously severs and staples tissue clamped in an end effector comprising an elongate channel, which holds a staple cartridge, and a pivotally attached anvil. An E-beam firing bar engages the channel and selectively engages the anvil during distal firing movements, wherein the tissue is severed and stapled driven upward from the staple cartridge to form against the anvil. In particular, a wedge integral to the staple cartridge is driven distally by a middle pin of the firing bar to effect stapling. A single lockout of the elongate channel responds to the presence of the wedge sled in its unfired position to allow the firing bar to fire. Otherwise, the single lockout prevent firing when the staple cartridge is missing or spent.

Abstract: A gas combustion-powered apparatus includes a piston chamber housing a driveable piston, and a combustion chamber having a generally flat wall assembly and a cup-shaped wall defining at least one combustion volume therebetween. The cup-shaped wall is moveable in relation to the piston chamber, and has a generally flat portion opposing, and generally parallel to, the generally flat wall assembly. An ignition source is in operable relationship to the combustion volume, which can ignite a combustible gas within the combustion volume. The piston forms at least a portion of the generally flat wall assembly when the piston is in an undriven state.