Surgical stapling device with tiltable anvil head

1. A surgical stapling device comprising:

a handle assembly including an approximation knob and a firing trigger;

an elongated body portion extending distally from the handle assembly;

a head portion including an anvil assembly and a shell assembly, the shell assembly housing a plurality of staples and the anvil assembly including an anvil head and an anvil center rod, the anvil head being pivotally secured to the anvil center rod about a pivot axis and being movable between an operative position and a tilted position;

an anvil retainer assembly configured to releasably engage the anvil assembly, the anvil retainer assembly including a locking member which is movable from a first position in which the anvil head is moved to or retained in the operative position to a second position in which the anvil head is able to pivot from the operative position to the tilted position;

wherein the anvil retainer assembly includes a body portion defining a longitudinal bore having an open distal end and a trocar, the trocar extending from the open distal end of the body portion and forming the locking member, the trocar being movable along the longitudinal bore between an advanced position and a retracted position, the advanced position defining the first position of the locking member and the retracted position defining the second position of the locking member; and

wherein the trocar is urged to the retracted position by a trocar biasing member.

2. A surgical stapling device according to claim 1 , wherein the trocar biasing member for urging the trocar to the retracted position is a coil spring.

3. A surgical stapling device according to claim 2 , wherein the proximal end of the trocar includes an annular flange and the longitudinal bore defines a shoulder, the trocar biasing member being positioned within the longitudinal bore about the trocar between the annular flange of the trocar and the shoulder defined within the longitudinal bore to urge the trocar to the retracted position.

4. A surgical stapling device according to claim 1 , further including a cam member supported on the body portion, the cam member being movable from a first position for retaining the trocar in the advanced position to a second position for allowing the trocar to move to the retracted position.

5. A surgical stapling device according to claim 4 , wherein the cam member is pivotally secured to the body portion.

6. A surgical stapling device according to claim 5 , wherein the cam member is pivotally supported within a longitudinal slot formed in the body portion.

7. A surgical stapling device according to claim 5 , wherein the cam member includes a distal finger and a proximally located recess, the distal finger being positioned to engage a pin supported on the proximal end of the trocar when the cam member is in its first position to retain the trocar in the advanced position against the urging of the trocar biasing member.

8. A surgical stapling device according to claim 7 , wherein the distal finger of the cam member includes an angled face such that engagement between the pin and the angled face urges the cam member to its second position.

9. A surgical stapling device according to claim 8 , further including a pusher operably associated with a firing trigger of the handle assembly, the firing trigger being actuable to advance the pusher within the elongated body portion from a retracted position to an advanced position to eject the plurality of staples from the shell assembly.

10. A surgical stapling device according to claim 9 , wherein the pusher includes at least one arm, the arm being positioned to prevent movement of the cam member from its first position to its second position until after the firing trigger has been actuated to move the pusher to its advanced position.

11. A surgical stapling device comprising:

a handle assembly including an approximation knob and a firing trigger;

an elongated body portion extending distally from the handle assembly;

a head portion including an anvil assembly and a shell assembly, the shell assembly housing a plurality of staples and the anvil assembly including an anvil head and an anvil center rod, the anvil head being pivotally secured to the anvil center rod about a pivot axis and being movable between an operative position and a tilted position;

an anvil retainer assembly configured to releasably engage the anvil assembly, the anvil retainer assembly including a locking member which is movable from a first position in which the anvil head is moved to or retained in the operative position to a second position in which the anvil head is able to pivot from the operative position to the tilted position; and

wherein the anvil assembly includes first and second slide members movably supported by the anvil center rod, the first slide member being pivotally connected to the anvil head on one side of the pivot axis by a first drive link and the second slide member being connected to the anvil head on the other side of the pivot axis by a second drive link, the first slide member being movable in relation to the second slide member to effect movement of the anvil head between the operative position and the tilted position;

further including a biasing member for urging the first and second slide members in relation to each other to position the anvil head in the tilted position;

wherein the first and second slide member biasing member is positioned between the first and second slide members to urge the first and second slide members apart.