Surgical clamping mechanism

A surgical stapling instrument comprising:

• a) an elongated staple cartridge having a cartridge clamping surface thereon, and a cartridge alignment surface thereon at a proximal end thereof adjacent said cartridge clamping surface, said cartridge alignment surface containing an alignment groove embedded therein;
• and
• b) an elongated anvil having:
• i) an anvil clamping surface thereon facing said cartridge clamping surface, ii) an anvil alignment surface thereon at a proximal end thereof adjacent said anvil clamping surface, said anvil alignment surface containing a pair of spaced-apart alignment ribs protruding therefrom, each of said alignment ribs having a rib leading edge thereon, and iii) a pair of outboard tissue stops extending therefrom at a proximal end of said anvil clamping surface, each of said outboard stops having a stop leading edge thereon located distally of each of said rib leading edges;
• wherein said elongated anvil is movable relative to said elongated staple cartridge from a rearward position in which said cartridge and anvil clamping surfaces are spaced from each other for insertion of tissue therebetween to a forward position in which said outboard tissue stops straddle said elongated cartridge adjacent a proximal end of said cartridge clamping surface and said cartridge and anvil clamping surfaces are adjacent to each other for clamping the tissue, and when said elongated tissue is moved from said rearward to said forward positions, said alignment ribs on said anvil alignment surface are received into and slide within said alignment groove in said cartridge alignment surface.