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.

Date of Patent:
Sep. 10, 1996

Filed:

Jun. 05, 1995
Applicant:
Inventors:

Kelvin P Self, Stillwater, OK (US);

Dirk A Wilson, Stillwater, OK (US);

Assignee:

Other;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21B / ;
U.S. Cl.
CPC ...
175 19 ; 1753256 ; 1753257 ; 175407 ;
Abstract

Several designs of reversible expanders (10, 50, 100, 150) are disclosed for use on an underground boring tool (14) of the type using an air impact hammer. The reversible expanders allow a borehole of larger diameter than the tool to be formed. The reversible expander (10) is interference fit on the outer surface of the boring tool by either pressing the expander onto the tool or by shrink fit. A reversible expander (50) has a split which allows the expander to be slid over the tool and then clamped in place by bolts. A reverse expander (100) is formed of two members (102, 104) which, when bolted together, form a taper lock engagement with the tool. Finally, a reversible expander (150) can be threaded onto threads on the outer surface of the tool.


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