Patent ID: 8702349
Filing Date: 2014-04-22
Classification: E21B,F16L

Abstract:
1. Apparatus for replacing underground pipe with a replacement pipe, comprising: a resistance plate for positioning against a wall through which a cable protrudes, the opposite end of the cable being connected to a mole having the replacement pipe connected thereto, said resistance plate having a slot therein of a size sufficient to allow passage of the mole therethrough; a pair of hydraulic cylinders positioned on opposite sides of said slot extending substantially parallel to each other and substantially perpendicular to said resistance plate to define a space into which the mole may be drawn by said cable; a pulling bridge secured to each of said cylinders at the end thereof opposite said resistance plate, said pulling bridge being reciprocally movable by operation of said cylinders in a pulling stroke and a recovery stroke, said pulling bridge having a cable gripper assembly thereon for griping the cable during the pulling stroke and releasing the cable during the recovery stroke; and a holding bridge releaseably mounted to said resistance plate spanning said slot, said holding bridge having a gripper assembly thereon for releasing the cable during the pulling stroke and gripping the cable during the recovery stroke, whereby said holding bridge may be removed to allow said mole to be drawn through said resistance plate into the space defined by said cylinders to facilitate detachment of the mole from the replacement pipe being pulled by the mole.