1
Allan T Fisk, David I Freed, Thomas A Mann: Pipe bursting and replacement method. Consolidated Edison Company of New York, Brooks Haidt Haffner & Delahunty, January 7, 1992: US05078546 (35 worldwide citation)

Tool for slitting and laterally expanding underground steel gas mains and inserting replacement plastic piping into the spread apart pipeline has a forward end cylindrical portion mounting a single, rearwardly angled blade to make only one line of cut, and a conical pipe spreader portion at its rear ...


2
Allan T Fisk, David I Freed, Thomas H Mann: Pipe bursting and replacement method. Consolidated Edison Company of New York, Brooks Haidt Haffner & Delahunty, June 24, 1997: USRE035542

Tool for slitting and laterally expanding underground steel gas mains and inserting replacement plastic piping into the spread apart pipeline has a forward end cylindrical portion mounting a single, rearwardly angled blade to make only one line of cut, and a conical pipe spreader portion at its rear ...



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