| 摘要 |
In a power tong of the type used in making up and breaking out threaded connections between pipe sections, the bearing surface between the upper cage plate and the tong top body plate is provided with improved means for reducing friction and other undesirable forces when the cage plate is rotatably driven with respect to the body plate. In a particular embodiment, the upper cage plate is provided with an arcuate groove which opens toward the opposing top body plate. The groove includes guide rollers mounted on vertical shafts for engaging the inner and outer arcuate walls of the groove to guide the cage plate when it is rotated. The groove also includes weight relief rollers mounted on horizontal shafts for providing a gap between the upper cage plate and its opposing body plate to eliminate metal-to-metal friction therebetween.
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