| 摘要 |
Apparatus which can be utilized on a drilling rig to aid in rotating drill pipe sections to connect and disconnect them, which uses a cat's head chain device to rotate the pipes but which avoids the danger arising when workmen wrap the chain around a pipe. The apparatus includes a jaw assembly which can be installed around a pipe section, and which has teeth on its inner surface to engage the pipe and sprockets on its outside to engage the cat's head chain so the chain can turn the jaw assembly. A stationary frame surrounds the jaw assembly while permitting it to rotate therewithin, the frame also carrying a backup roller to keep the chain engaged with the sprockets of the jaw assembly.
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