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:
Dec. 08, 2009
Filed:
Apr. 27, 2007
Applicants:
Olaf Koch, Kaufering, DE;
Josef Starkmann, Hurlach, DE;
Guenther Domani, Frastanz, AT;
Inventors:
Assignee:
Hilti Aktiengesellschaft, Schaan, LI;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21B 10/44 (2006.01);
U.S. Cl.
CPC ...
Abstract
A rotary-percussion drill includes a four-start helical shaft () having a fourfold rotationally and mirror-symmetrical helix cross-section, with radially projecting convexly formed helical webs () extending from a concave groove bottom () up to the envelope circle () and having an undercut () with respect to a web width (S).