Surgical stapling instrument with articulated stapling head assembly on rotatable and flexible support shaft

A surgical stapling instrument for applying one or more surgical staples to tissue, comprising:

• a stapling head assembly including a fixed jaw which supports a staple holder for receiving one or more surgical staples, a movable jaw which supports an anvil for clamping the tissue against said staple holder when said jaws are closed, and a staple driver for driving the staples from said staple holder into the tissue and against said anvil;
• an actuator handle assembly including a jaw closure lever for closing said jaws to move said anvil into a tissue clamping position and a staple firing trigger for actuating said staple driver;
• a shaft assembly for mounting said stapling head assembly on said actuator handle assembly;
• a closure cable connecting said movable jaw to said jaw closure lever and extending through said shaft assembly for pulling said movable jaw toward said fixed jaw when said jaw closure lever is actuated;
• a firing cable connecting said staple driver to said staple firing trigger and extending through said shaft assembly for actuating said staple driver when said staple firing trigger is actuated;
• and
• jaw coupling means for slidably and pivotally coupling said movable jaw to said fixed jaw, said jaw coupling means including a slidable roller pin slidably and rotatably mounted in guide slots formed in each of said jaws;
• wherein:
• said stapling head assembly includes a tissue retaining pin mounted inside said fixed jaw, said tissue retaining pin being movable from a retracted position within said fixed jaw when said jaws are open to an extended position engaging said movable jaw when said jaws are closed;
• a pin placement mechanism mounted on said fixed jaw for moving said tissue retaining pin between the retracted position and the extended position;
• and
• said tissue retaining pin is mounted on a cantilever spring arm inside said fixed jaw which supports said retaining pin for movement between the retracted and extended positions;
• a pin placement arm pivotally mounted inside said fixed jaw for engaging said cantilever spring arm and moving said retaining pin between the retracted and extended positions;
• and
• wherein:
• said pin placement arm includes a cam projecting laterally therefrom and extending through a window formed in said fixed jaw;
• and
• said actuating means comprises a cam actuator finger on said movable jaw for engaging said cam when said movable jaw is closed to pivot said pin placement arm and move said retaining pin from the retracted position to the extended position.