Patent ID: 7255516

Claim:
A method for replacement of an underground pipe, comprising: inserting a cable through an existing pipeline from a first end to a second end thereof; connecting a free end of the cable extending from the second end of the pipeline to an impactor, which impactor includes a bursting head having a rearwardly opening recess, a striker mounted for sliding movement within the head, a distributing mechanism responsive to pressure fluid supplied through an inlet to cause the striker to reciprocate in the rearwardly opening recess of the head to deliver forward impacts against the head, and a pulling connection to which the cable is connected; pulling the impactor with the cable using a cable pulling system disposed at the first end of the pipeline, which cable pulling system pulls the cable in a plurality of repeated cyclic pulling strokes, including a holder that engages the cable and a cylinder having a movable piston operative to move the holder along the pulling stroke; operating the impactor to deliver impacts against the head in the same direction as the pulling force during a cyclic pulling stroke; and reducing operation of the impactor between cyclic pulling strokes so that the impactor does not substantially move between strokes.