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:
Mar. 30, 1993
Filed:
Mar. 13, 1992
Burkhard Mayer, Herrenberg, DE;
Harmut Hoppe, Horb a. N., DE;
Fischerwerke Artur Fischer GmbH & Co. KG, Waldachtal 3/Tumlingen, DE;
Abstract
The drill tool for drilling a drilled hole with an undercut in a wall has a drill tool shaft having a drill head at a free end of the drill tool shaft, a depth insertion stop formed on the drill tool shaft to limit an insertion depth of the drill tool in the drilled hole and cutting elements projecting laterally from the drill head for making the undercut. The drill tool shaft (15) has an enlarged portion (10) acting as a pivot bearing for making the undercut spaced approximately equally from the insertion depth stop (4) and the drill head (6). To prevent sticking of the drill tool in the drilled hole the drill tool shaft (15) also has a cylindrical step portion (11) connected to the enlarged portion (10) and located between the enlarged portion (10) and the insertion depth stop (4). A discontinuous transition between the enlarged portion (10) and the cylindrical step portion (11) forms a scraping edge (12) and the cylindrical step portion (11) has a diameter less than a diameter of the enlarged portion (10). Another cylindrical step portion (14) with another scraping edge can also be provided.