Pipe bursting and replacement apparatus
DCFirst Claim
1. A pipe bursting tool for longitudinally slitting and laterally expanding a length of steel pipe, said tool having a forward end and a rearward end, comprising a substantially cylindrical portion including said forward end and whose diameter is smaller than the inner diameter of said pipe so as to be received therein, a truncated substantially conical spreader portion for laterally expanding said pipe and having a truncated apex end conjoining with said cylindrical portion and a base end adjacent to said rearward end of said tool which is substantially larger than said inner diameter of said pipe, said spreader portion having a conical surface-generating side element aligned with and forming a rearward extension of a cylindrical surface-generating side element of said cylindrical portion and together providing a straight side surface of said tool, said conical spreader portion thereby being eccentrically disposed with respect to the longitudinal axis of said cylindrical portion, and a fixed blade member mounted on and projecting outwardly from a second surface of said tool which is opposite to its said straight side surface, said blade member having an angularly rearward extending and forwardly facing cutting edge.
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Abstract
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.
44 Citations
19 Claims
- 1. A pipe bursting tool for longitudinally slitting and laterally expanding a length of steel pipe, said tool having a forward end and a rearward end, comprising a substantially cylindrical portion including said forward end and whose diameter is smaller than the inner diameter of said pipe so as to be received therein, a truncated substantially conical spreader portion for laterally expanding said pipe and having a truncated apex end conjoining with said cylindrical portion and a base end adjacent to said rearward end of said tool which is substantially larger than said inner diameter of said pipe, said spreader portion having a conical surface-generating side element aligned with and forming a rearward extension of a cylindrical surface-generating side element of said cylindrical portion and together providing a straight side surface of said tool, said conical spreader portion thereby being eccentrically disposed with respect to the longitudinal axis of said cylindrical portion, and a fixed blade member mounted on and projecting outwardly from a second surface of said tool which is opposite to its said straight side surface, said blade member having an angularly rearward extending and forwardly facing cutting edge.
- 15. Apparatus for longitudinally slitting and laterally expanding a length of underground steel pipe, comprising an elongated pipe bursting tool having a forward end and a rearward end, an elongated pneumatically actuated impact ramming tool connected to and extending in tandem relation rearwardly of said pipe bursting tool, said ramming tool having a longitudinal axis which is parallel to the longitudinal axis of said pipe bursting tool, and connection means on said forward end of said pipe bursting tool for connecting a wire pulling rope thereto, said pipe bursting tool comprising a cylindrical portion including said forward end and whose diameter is smaller than the interior diameter of said pipe so as to be received therein, a truncated substantially conical spreader portion having a truncated apex end conjoining with said cylindrical portion and a base end adjacent to said rearward end of said tool which is substantially larger than said inner diameter of said pipe, said conical portion being eccentrically disposed with respect to said cylindrical portion, and pipe slitting means mounted on and projecting outwardly from said pipe bursting tool.
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18. A tool for longitudinally slitting and laterally expanding a length of steel pipe, said tool having a forward end and a rearward end and comprising a longitudinally extending cutter portion including said forward end of said tool and having opposite longitudinal sides and transverse dimensions smaller than the inner diameter of said pipe so as to be received therein, a pipe cutter mounted on and having a forwardly facing cutting edge projecting outwardly from said cutter portion on one of said sides thereof for slitting said pipe along one line of cut and means on the other of said sides thereof for engaging the interior surface of said pipe, and a spreader portion adjacent to said rearward end of said tool and having a narrow forward end adjacent to said cutter portion, a wider rearward end, and a substantially longitudinal side extending rearwardly between its said forward and rearward ends with respect to said other side of said cutter portion, said spreader portion being disposed eccentrically with respect to the longitudinal axis of said cutter portion in the direction of said one side of said cutter portion with its said narrow forward end disposed whereby, at least adjacent to said forward end it will enter said one line of cut and with its said wider rearward end disposed to follow its said forward end within said line of cut to progressively spread said slit pipe substantially laterally along said one line of cut as said tool is moved in the direction of its said forward end through said slit pipe..Iaddend. .Iadd.19. A tool according to claim 18, wherein said means on the other of said sides of said cutter portion comprises at least one skid plate attached to said cutter portion..Iaddend. .Iadd.20. A tool according to claim 18, wherein said means on the other of said sides of said cutter portion comprises at least one rolling idler element mounted on said cutter portion..Iaddend.
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19. Iadd. . A tool for longitudinally slitting and laterally expanding a length of pipe, said tool having a forward end and a rearward end and comprising a cutter portion adjacent to said forward end and whose transverse dimensions are smaller than the inner diameter of said pipe so as to be received therein, a pipe cutter mounted on and projecting outward from said cutter portion on one side thereof for slitting said pipe when said tool is moved therethrough in a forward direction, said cutter portion having an opposite longitudinal side, and a spreader portion for laterally expanding said slit pipe and having a forward end connected to said cutter portion which is smaller than the diameter of said pipe to be received therein and a rearward end which is wider than said forward end, said rearward end of said spreader portion being eccentrically disposed with respect to the longitudinal axis of said cutter portion towards said one side thereof, said spreader portion having an opposite side which extends substantially longitudinally and rearwardly between its said forward and rearward ends with respect to said opposite longitudinal side of said cutter portion, and said spreader portion widening in lateral direction between its said forward and rearward ends to engage and spread apart opposite sides of said slit pipe as said tool is moved therethrough in said forward direction..Iaddend.
Specification