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. 05, 1988
Filed:
Feb. 11, 1987
Applicant:
Inventors:
Assignee:
Gewerkschaft Eisenhutte Westfalia GmbH, Postfach, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21D / ;
U.S. Cl.
CPC ...
405294 ; 405293 ; 405302 ;
Abstract
A mine roof support has a slidable extension at the front end of an auxiliary roof cap pivoted for swinging up and down on a main cap. To prevent the extension from being extended when the angle of inclination of the auxiliary cap is too high an insulative cylindrical block is fitted to say the auxiliary cap to partially rotate as the auxiliary cap pivots. A flattened region on the block supports a metallic plate and indexes as the auxiliary cap pivots. A resiliently-mounted proximity switch on the main cap senses the presence of the plate and produces a signal to prevent the extension from being extended.