US Patent 10980540 Spring loaded anvil retainer

A surgical stapling device includes a handle assembly, a body portion extending distally from the handle assembly, a head portion including an anvil retainer and a shell assembly. The anvil retainer is movable in relation to the shell assembly between unapproximated and approximated positions. A tube surrounds a portion of the anvil retainer, wherein the anvil retainer includes a distal annular protrusion for releasably engaging an anvil assembly and wherein the anvil assembly includes a center rod.