| 摘要 |
A tubular body portion has an internally threaded portion and a cylindrical portion and includes an annular recess portion therebetween. The annular recess portion includes a first shoulder adjacent the threaded portion and a second shoulder adjacent the cylindrical portion. A circumferential cutting edge portion is provided at the juncture of the second shoulder and the adjacent cylindrical portion. A first conduit to be joined is extended through the cylindrical portion into substantially abutting relation with the first shoulder. A suitable expanding tool expands the end portion of the first conduit outwardly into the annular recess portion and against the cutting edge to produce a distinct gouge or circumferential cut therein. The coupling remains rotational relative to the first conduit with the end portion thereof expanded into the annular recess portion. A second conduit to be joined is threadedly advanced into the threaded end portion of the coupling by rotation of the coupling. The second conduit moves into underlapping relation with the expanded end portion of the first conduit and on continued advance urges the expanded end portion into further abutting relation with the annular recess portion and the cutting edge portion of the coupling so that additional portions of the expanded end thereof are rolled back into the annular recess portion to mechanically lock the first conduit to the coupling. Thus, the conduits are engaged to each other and to the coupling to provide a connection sufficient to resist axial forces tending to separate the conduits from the coupling.
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