| 摘要 |
Rotary internal pipe clamp apparatus for use in welding pipes together end to end, said apparatus having a first set of circularly spaced pipe engagement elements for disposition within the end of one section of pipe, and having a second set of circularly spaced pipe engagement elements for disposition in the end of a second length of pipe abutted end to end with the first length of pipe. Each set of circularly spaced pipe engagement elements is expanded and retracted by rotation of a circular disc to which said pipe engagment elements are linked by toggle elements. In addition, the apparatus includes a welding back up assembly which is expandable and retractable simultaneously with the second set of pipe engagement elements. The welding back up assembly includes plural peripheral bands or strips which are supplemented by shorter peripheral bands or strips which separately retract and expand.
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