Importance

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Abstract

A self locking and unlocking elevator for use with drill pipe is disclosed which, in a specific embodiment, includes a cam body which defines two symmetrically positioned cam surfaces. Each of these cam surfaces serves to support the upper end of a respective jaw, the lower end of which is shaped to clamp and hold the box end of a length of drill pipe. A collar is disposed around the jaws and is mechanically interlocked with the jaws such that both the collar and the jaws are suspended from the cam body. A plate is positioned below the collar above the box end of a clamped length of drill pipe and is secured to the cam body so as to move between a lower position in which the collar and jaws hang from the cam body, and an upper position in which the jaws are supported via the collar and the plate by the box end of the clamped drill pipe. The jaws are shaped such that they move by force of gravity to a closed clamping position when suspended from the cam body, and they open to release the drill pipe when supported by the movable plate.

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First Claim