04983071 is referenced by 26 patents and cites 14 patents.

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 rearward end. The conical spreader portion is eccentrically disposed with respect to the forward end cylindrical portion. A single roller type pipe slitter aligned with the fixed blade may be mounted on a removable extension of the forward end cylindrical portion, to initially groove and weaken the pipe along the intended line of cut. A pneumatically operated impact ram is attached to the rearward end of the tool, as is the leading end of the replacement piping. A wire cable pulls the tool through the underground pipe, thereby grooving, slitting and laterally expanding the pipe. The spacing of the roller slitter in advance of the fixed knife blade is dimensionally related to the length of any coupling or clamp as may be anticipated along the line of cut, and the spacing distance of the fixed knife blade forwardly of the conical spreader portion is related to the cone angle of the latter to increase hoop tension immediately in front of the fixed blade as the cutting proceeds.

Title
Pipe bursting and replacement apparatus and method
Application Number
7/524231
Publication Number
4983071
Application Date
May 15, 1990
Publication Date
January 8, 1991
Inventor
Thomas A Mann
Littleton
MA, US
David I Freed
Weston
MA, US
Allan T Fisk
Needham
MA, US
Agent
Brooks Haidt Haffner & Delahunty
Assignee
Consolidated Edison Company of New York
NY, US
IPC
F16L 55/18
F16L 1/00
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