Patent attributes
Apparatus for replacing underground pipe is described, including a resistance plate from which a pair of hydraulic cylinders extend perpendicularly in parallel with each other. The cylinders operate cyclically with a pulling bridge having a cable gripper to provide a sequence of pulling strokes to a cable pulling a mole. The mole pulls a replacement pipe behind it through the old pipe, which has been burst, slit, or otherwise expanded by the mole. The resistance plate is provided with a slot, and the cylinders are positions such as to allow the mode to be pulled substantially completely into the apparatus. A holding bridge is releasably mounted spanning the slot in the reaction plate to position a second cable gripper for holding the cable on return stroke of the pulling bridge. The holding bridge may be removed at the end of the pulling operation to accommodate the mole.
