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:
May. 25, 1976
Filed:
Mar. 12, 1975
Applicant:
Inventors:
Siegfried Sigott, Zeltweg, OE;
Hubert Schwelberger, Zeltweg, OE;
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21C / ;
U.S. Cl.
CPC ...
299 89 ; 175 91 ; 299 10 ;
Abstract
A tool body defines an axis of rotation for the tool and has a periphery surrounding said axis. A plurality of cutter bits are carried by said body and protrude substantially radially from said periphery and have free ends. Said cutter bits are arranged in a plurality of groups which are spaced in the direction of said axis. The free ends of the cutter bits of each of said groups define a circle. The circles defined by the free ends of the cutter bits of said groups increase in diameter in one direction along said axis.