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:
Jan. 05, 1993
Filed:
May. 15, 1992
Erwin Schiefer, Munich, DE;
Hilti Aktiengesellschaft, , LI;
Abstract
An expansion dowel has a friction reducing coating on the contacting surfaces formed by an inside surface an an expansion sleeve and an outside surface of the shank contacting the inside surface of the sleeve. The coating effects a smaller friction value between the expansion sleeve and the expansion part than the friction value between the expansion sleeve and the surface of a borehole into which the dowel is inserted. This difference in friction assures an effective re-expansion of the expansion dowel in a fractured or broken tensile zone of a receiving material containing the borehole. In addition to the coating, protrusions arranged in pairs are formed on the outside surface of the expansion sleeve for maintaining contact with the borehole surface, particularly in the broken tensile zone during large displacement of the expansion dowel.