×

Horizontal boring apparatus and method

  • US 4,993,503 A
  • Filed: 03/27/1990
  • Issued: 02/19/1991
  • Est. Priority Date: 03/27/1990
  • Status: Expired due to Fees
First Claim
Patent Images

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.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×