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:
Jul. 26, 1994
Filed:
Dec. 08, 1992
Erich Leibhard, Munich, DE;
Franz Popp, Buchloe, DE;
Wolfgang Ludwig, Landsberg, DE;
Thomas Schwaninger, Nenzing, AT;
Hilti Aktiengesellschaft, Furstentum, LI;
Abstract
The retention value of a screw previously inserted into a wooden railroad tie is increased by an axially extending sleeve ( 20 ) having an external thread ( 24 ) and an internal thread (25). The thread revolutions of the internal thread (25) are offset axially by half (h) the thread pitch (H) of the external thread (24). Due to this offset of the threads, the screw is positioned in the sleeve so that its threads are located between the external thread revolutions affording a new retention, while the external thread (24) seats within the thread previously formed in the wooden railroad tie by the screw.