US Patent 10952728 Powered surgical instruments with firing system lockout arrangements

A stapling assembly comprising a shaft, a first iaw, a second iaw, a detachable cartridge portion, a firing member, a motor-driven firing system, and a lockout is disclosed. The firing member comprises a first cam configured to engage the first jaw and a second cam configured to engage the second jaw when the firing member is advanced from an initial position. The first iaw comprises a clearanced opening configured to receive the first cam when the firing member is in the initial position such that the first cam is not engaged with the first jaw when the firing member is in the initial position. The motor-driven firing system is configured to advance the firing member toward a distal end of the stapling assembly. The lockout is configured to block the advancement of the firing member when the detachable cartridge portion is not attached to the stapling assembly.