Horizontal boring apparatus and method
First Claim
1. Dual mode boring apparatus for forming a generally horizontal underground passage for a utility conduit or the like comprisinga tool head having elongated body structure that defines a tool axis and structure defining a cutting face at one end of said elongated body structure,cutting bit structure fixed to and projecting forwardly from said cutting face, said cutting bit structure including pilot structure defining a pilot axis offset from said tool axis,structure defining a cutting fluid orifice in said cutting face adjacent said cutting bit structure for directing a high velocity jet of cutting fluid forwardly of said cutting face, andcoupling structure for attaching said elongated body structure to a drill string such that said cutting tool face is offset from said drill string axis,said boring apparatus being adapted to be advanced and concurrently driven in rotation to move said cutting face in an orbital path about said tool axis in boring action in relatively soft underground strata and to move said cutting face in a rotary path about said pilot structure in rotary boring action in underground strata that is harder than said relatively soft underground strata to bore an underground passage, and to be advanced without rotation to produce a change in direction of said underground passage in the direction of offset of said pilot structure from said tool axis.
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Accused Products
Abstract
Boring apparatus for forming a generally horizontal underground passage for a utility conduit or the like that includes a tool head with elongated body structure and a cutting face of ellipto-conical form at one end of the elongated body structure. The cutting face has a major axis and a minor axis and cutting bit structure is fixed to and projects forwardly from the cutting face and extends substantially the full width of the cutting face generally along the major axis. The tool head also includes coupling structure for attaching the tool head to a drill string such that the cutting tool face is offset from the drill string axis. Structure in the cutting face defines a cutting fluid orifice adjacent the cutting bit structure for directing a high velocity jet of cutting fluid forwardly of the cutting tool face. The tool body is adapted to be advanced and concurrently driven in rotation to move the cutting face in orbital boring action about the drill string axis to bore an underground passage and to be advanced without rotation to produce a change in direction of the underground passage in the direction of offset from the drill string axis.
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Citations
26 Claims
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1. Dual mode boring apparatus for forming a generally horizontal underground passage for a utility conduit or the like comprising
a tool head having elongated body structure that defines a tool axis and structure defining a cutting face at one end of said elongated body structure, cutting bit structure fixed to and projecting forwardly from said cutting face, said cutting bit structure including pilot structure defining a pilot axis offset from said tool axis, structure defining a cutting fluid orifice in said cutting face adjacent said cutting bit structure for directing a high velocity jet of cutting fluid forwardly of said cutting face, and coupling structure for attaching said elongated body structure to a drill string such that said cutting tool face is offset from said drill string axis, said boring apparatus being adapted to be advanced and concurrently driven in rotation to move said cutting face in an orbital path about said tool axis in boring action in relatively soft underground strata and to move said cutting face in a rotary path about said pilot structure in rotary boring action in underground strata that is harder than said relatively soft underground strata to bore an underground passage, and to be advanced without rotation to produce a change in direction of said underground passage in the direction of offset of said pilot structure from said tool axis.
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16. Boring apparatus for forming a generally horizontal underground passage for a utility conduit or the like comprising
a tool head having elongated body structure and a cutting face of ellipto-conical form at one end of said elongated body structure, said cutting face having a major axis and a minor axis, cutting bit structure fixed to and projecting forwardly from said cutting face and extending substantially the full width of said cutting face generally along said major axis, coupling structure for attaching said elongated body structure to a drill string such that said cutting tool face is offset from said drill string axis, and structure defining a cutting fluid orifice in said cutting face adjacent said cutting bit structure for directing a high velocity jet of cutting fluid forwardly of said cutting face, said boring apparatus being adapted to be advanced and concurrently driven in rotation to move said cutting face in orbital boring action about said drill string axis to bore an underground passage and to be advanced without rotation to produce a change in direction of said underground passage in the direction of offset from said drill string axis.
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20. A method for forming a generally horizontal underground passage for a utility conduit or the like comprising the steps of
providing a tool head that has elongated body structure and a cutting face at one end of said elongated body structure, cutting bit structure fixed to and projecting forwardly from said cutting face, and structure defining a cutting fluid orifice in said cutting face adjacent said cutting bit structure, attaching said elongated body structure to a drill string such that said cutting tool face is offset from the axis of said drill string, concurrently rotating and advancing said tool head along an underground path to move said cutting bit structure in orbital boring action about said drill string axis while concurrently directing a high velocity jet of cutting fluid from said orifice defining structure at an angle to said drill string axis in the same direction as said cutting tool face is offset from said drill string axis to bore a substantially straight underground passage, and advancing said tool head along an underground path without rotation while concurrently directing said high velocity jet of cutting fluid from said orifice defining structure at an angle to said drill string axis in the same direction as said cutting tool face is offset from said drill string axis to produce a change in direction of said underground passage in the direction of said high velocity jet of cutting fluid.
Specification