| 摘要 |
A power apparatus and method for making and breaking joints in drill pipe strings in oil wells, in which a single torquing cylinder (24), that always moves in a single direction while torquing, both makes and breaks the joints. Three levels (21, 22, 23) of jaw elements (52, 52a) are employed, the top and bottom jaw levels (21, 23) being identical to each other, all jaw elements being interconnected as by a frame (10). Other cylinders (52, 52a) close the jaws (36, 37) at each level. The apparatus is moved vertically; two levels of jaw elements are employed for making and another combination of two levels is employed for breaking. Special die and cam means (66) are provided to grip the drill pipe. Means (94, 101) are provided to position the jaws in the middle level at the proper location after each use, for different sizes of pipe. Special bearing, pivot and adjustment means (66, 73) are provided in the jaw elements. The jaw elements operate in only one direction, and are self energizing.
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