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:
Nov. 04, 2014
Filed:
Mar. 15, 2012
Applicants:
Wilfried Weigel, Werne, DE;
Gerhard Wülfing, Velbert, DE;
Peter Rahms, Billerbeck, DE;
Inventors:
Assignee:
Tiefenbach Control Systems GmbH, Bochum, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21D 23/26 (2006.01); E21C 35/16 (2006.01);
U.S. Cl.
CPC ...
E21D 23/26 (2013.01); E21C 35/16 (2013.01);
Abstract
A hydraulic circuit for longwall support for use in underground mining for supporting a longwall by means of a plurality of support shields includes in the annular piston line of each cylinder/piston unit a pressure sensor. The pressure sensor, upon reaching a predetermined maximum pressure activates a pressure deviation signal, causes the entire longwall to be depressurized by means of a longwall shut-off valve. The pressure deviation signal is blocked for one of the hydraulic valves against each triggering signal.