Oilfield elevator

1. An oilfield elevator comprising:

a first body segment including a first end and an outboard end;

a second body segment including a first end and an outboard end, the first body segment being pivotally connected through a hinge at its first end to the first end of the second body segment and the first and second body segments being releasably connectable at their outboard ends to form a pipe-receiving opening therebetween,

a locking mechanism operable by axial movement of the first body segment relative to the second body segment to control pivotal rotation about the hinge;

an actuation lever positioned between the first body segment and the second body segment, the actuation lever including a protrusion thereon and being moveable to drive the protrusion against the first body segment to drive the first body segment axially relative to the second body segment; and

wherein the locking mechanism includes abutting shoulders on the first and second body segments at the hinge and the abutting shoulders can be moved out of abutment to permit the first segment to rotate about the hinge.

2. The oilfield elevator of claim 1 wherein the locking mechanism further comprises a set of interlocking hooks at the outboard ends of the first and second body segments, such interlocking hooks being engaged and disengaged by axial movement of the first body segment relative to the second body segment.

3. The oilfield elevator of claim 1 further comprising a biasing member to resist axial movement to unlock the first and second body segments.

4. The oilfield elevator of claim 1 further comprising a driver to drive movement of the actuation lever.

5. The oilfield elevator of claim 4 wherein the driver includes a hydraulic cylinder.

6. The oilfield elevator of claim 4 wherein the driver includes a pneumatic cylinder.

7. The oilfield elevator of claim 4 wherein the driver is selected to have insufficient power to drive the actuation lever when a pipe is supported in the pipe-receiving opening.

8. An oilfield elevator comprising:

a first body segment including a first end, a barrel at the first end and an outboard end, the barrel including a cam surface;

a second body segment including a first end, lugs at the first end and an outboard end,

a hinge formed by the pivotal connection of the barrel, lugs and a hinge pin; wherein the first and second body segments are releasably connectable at their outboard ends to form a pipe-receiving opening therebetween;

an actuation lever positioned at the hinge between the barrel and lugs, the actuation lever including a cam surface; and

a power cylinder connected at one end to the actuation lever and at another end to a connection on the second body segment;

wherein the actuation lever and power cylinder move cooperatively in a planar direction to move the first and second body segments axially by interaction between the actuation lever cam surface and the barrel cam surface.

9. The oilfield elevator of claim 8 wherein the actuation lever cam surface is a protrusion and the barrel cam surface is a detent.

10. The oilfield elevator of claim 8 further comprising a biasing member to bias the first body segment into axially alignment with the second body segment.

11. The oilfield elevator of claim 8 wherein the power cylinder is selected to have insufficient power to drive the actuation lever when a pipe is supported in the pipe-receiving opening.

12. A method for operating a pipe elevator comprising:

(a) providing a pipe elevator including:

a first body segment with a first end and an outboard end,

a second body segment with a first end and an outboard end, the first body segment being pivotally connected through a hinge at its first end to the first end of the second body segment,

wherein the first and second body segments are releasably connectable at their outboard ends to form a pipe-receiving opening therebetween,

a locking mechanism operable to be locked and unlocked by axial movement of the first body segment relative to the second body segment to control pivotal rotation about the hinge, the locking mechanism including abutting shoulders on the first ends of first and second body segments at the hinge;

an actuation lever positioned between the first ends of the first body segment and the second body segment, the actuation lever including a protrusion thereon; and

(b) rotating the actuation lever relative to the first and second body segments, thereby driving the protrusion against the first body segment and causing the first body segment to move axially relative to the second body segment to release the locking mechanism by moving the abutting shoulders out of abutment before any rotational movement of the first body segment and the second body segment is initiated about the hinge.

13. The method for operating a pipe elevator of claim 12 wherein rotating the actuation lever moves the first body segment upwardly relative to the second body segment.

14. The method for operating a pipe elevator of claim 12 further comprising, (c) continuing to rotate the actuation lever, thereby driving the first body segment to rotate about the hinge.

15. The method for operating a pipe elevator of claim 12 wherein rotating the actuation lever cannot proceed with a pipe supported in the pipe-receiving opening of the elevator.

16. The method for operating a pipe elevator of claim 12 further comprising, (c) continuing to rotate the actuation lever, causing the protrusion on the actuation lever to engage a driving detent within the first body segment to drive the first body segment to rotate about the hinge.

17. An oilfield elevator comprising:

a first body segment including a first end and an outboard end;

a second body segment including a first end and an outboard end, the first body segment being pivotally connected through a hinge at its first end to the first end of the second body segment and the first and second body segments being releasably connectable at their outboard ends to form a pipe-receiving opening therebetween;

the first body segment being axially movable relative to second body segment from a locked position to a rotatable position;

shoulders on the first ends of the first body segment and the second body segment that abut each other while in the locked position to prevent rotation of the first body segment relative to the second body segment, and which move out of abutment when the first body segment is moved to the rotatable position;

an actuation lever mounted between the first ends of the first and second body segments, the actuation lever being rotatable relative to the first and second body segments from a locked position to a driving position;

a protrusion on the actuation lever that moves the first body segment axially from the locked position to the rotatable position when the actuation lever is rotated relative to the first and second body segments from the locked position to the driving position; and

a driving detent formed on the first body segment that is engaged by the protrusion while the actuation lever is in the driving position, such that continued rotation of the actuation lever rotates the first body segment to an open position.

18. The oilfield elevator of claim 17 , wherein the locking mechanism further comprises a set of interlocking hooks at the outboard ends of the first and second body segments, such interlocking hooks being engaged and disengaged by the axial movement of the first body segment relative to the second body segment.

19. The oilfield elevator of claim 17 , further comprising a spring mounted between the first ends of the first and second body segments, the spring biasing the first body segment toward the locked position.

20. The oilfield elevator of claim 17 , further comprising a locking detent on the first end of the first body segment, the protrusion on the actuation lever being positioned within the locking detent while in the locked position.