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:
Apr. 14, 1987
Filed:
Mar. 11, 1986
Gunter Blumenthal, Herten-Westerholt, DE;
Bochumer Eisenhuette Heintzmann GmbH & Co., Bochum, DE;
Abstract
An arrangement for supervising and controlling synchronous displacement of respective pistons of two cylinder-and-piston units, especially of an advancement and a roof cap displacement unit of a roof support assembly for use in underground mining, comprises first and second conduit systems each having two branches each connected with one of the piston and annular spaces of a different one of the units; a switching valve interposed between pressure and a return conduits and the first and second conduit systems; and first and second shut-off valves respectively interposed in those of the branches of the first and second conduit systems which lead to the piston spaces. Measurement devices measure the extent of displacement of each of the pistons, and a control and regulating arrangement determines from the outputs of the measurement devices which of the piston leads the other and causes that of the first and second shut-off valves which is associated with the leading piston to temporarily close and thus discontinue the action of the pressure differential on the leading piston until synchronism in the displacement of the two pistons is restored.