Cartridge assembly for a surgical stapling instrument

In a disposable cartridge assembly for a surgical stapling instrument, an anvil carrying component comprising constituent anvil segments, each segment being integrally secured at one end thereof to a central hub portion by a relatively flexible linkage and being formed, at an opposite end thereof with a component anvil surface so as to form together a composite anvil surface, each anvil segment being formed, adjacent said opposite end with a slot which together form a groove, said segments being flexibly displaceable between a retracted and an expanded position;

• a compression band tightly fitted around said segments for biasing said segments into said retracted position wherein said composite anvil surface has a first diameter, and a locking ring adapted to fit into said groove so as to maintain said segments in their expanded position wherein said composite anvil surface has a second larger diameter, said ring being formed with a succession of tooth-like projections adapted to project into the spaces between the segments so as to prevent movement of the segments with respect to each other, a bored anvil base member to which an instrument adjusting rod is adapted to be coupled, said base member being articulated to said anvil hub portion so as to permit for relative rotational displacement between them, said hub portion being formed with a circular bead which is adapted to be snap-fitted into a corresponding groove formed in an adjacent surface in said base member so as to allow for said relative rotational displacement, the arrangement being such that upon disengagement of said locking ring from said anvil segments, the latter are displaced under said biasing force into said retracted position.