The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 19, 1991
Filed:
Mar. 27, 1990
Edward E Fischer, Acton, MA (US);
Thomas H Mann, Littleton, MA (US);
Allan T Fisk, Needham, MA (US);
Electric Power Research Institute, Palo Alto, CA (US);
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.