Patent ID: 7857187

Claim:
A tiltable anvil assembly comprising: a center rod; a head assembly including a housing, a post, an anvil plate having staple deforming pockets, and a backup member, the head assembly being pivotally secured to the center rod and pivotal in relation to the center rod between an operative position and a tilted position, wherein the backup member is movable about the post from a first position in which a portion of the backup member is positioned to prevent movement of the head assembly from the operative position to the tilted position, to a second position in which the backup member is positioned to permit movement of the head assembly in relation to the center rod from the operative position to the tilted position, and further including a retainer member positioned in the head assembly to prevent movement of the backup member from the first position to the second position until a predetermined force has been applied to the backup member, wherein the retainer member includes a plurality of deformable tabs positioned to engage the backup member and deform in response to the predetermined force applied to the backup member.