Locking articulation mechanism for surgical stapler

1. A surgical stapler comprising:

a handle assembly;

an elongated body extending from the handle assembly;

an articulable tool assembly mounted on a distal end of the elongated body; and

an articulation mechanism operably connected to the handle assembly and configured to selectively articulate and securely lock the tool assembly in one or more positions, the articulation mechanism having:

a main shaft member mounted for rotation and connected to an articulation linkage;

a stationary retainer having an opening for receiving a shaft portion of the main shaft member;

a cam lock having a bore configured to receive the shaft portion of the main shaft member, the cam lock having cam locking surfaces and a locking tab;

a biasing member disposed between the retainer and cam lock;

a locking cover defining recesses for receiving the locking tab, the

recesses including a central recess positioned to correspond to a nonarticulated position;

an articulation handle having cam surfaces configured to engage the cam locking surfaces of the cam lock, wherein the engagement of the cam locking surfaces and the cam surfaces moves the cam lock against the bias of the biasing member.

2. The surgical stapler according to claim 1 , wherein the recesses are defined by dividers having chamfered surfaces.

3. The surgical stapler according to claim 2 , wherein the dividers differ in size.

4. The surgical stapler according to claim 2 , wherein the dividers include central dividers defining a central recess and other dividers defining recesses for articulated positions.

5. The surgical stapler according to claim 4 , wherein the chamfers on the central dividers are relatively large, and wherein the chamfers on the dividers defining recesses for articulated positions are relatively small.

6. The surgical stapler according to claim 1 , wherein the locking cover has a semi-circular extension having ends configured to interact with the cam lock and prevent over-rotation.

7. The surgical stapler according to claim 1 , wherein the articulation handle has cutouts that align with an opening formed on the shaft portion, and further comprising a locking pin for securing the articulation handle to the main shaft, the cutouts allowing the articulation handle to pivot before rotating the main shaft.

8. The surgical stapler according to claim 1 , wherein a yoke is attached to the main shaft member and the articulation linkage.

9. The surgical stapler according to claim 1 , wherein the articulation mechanism further includes a housing configured to receive the retainer therein, the retainer being stationary relative to the housing.