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:
Jun. 04, 2002
Filed:
Dec. 14, 1999
Abstract
A valve arrangement ( ) for hydraulically actuated machinery installations, especially for powered support assemblies in underground mining, with hydraulically actuated working valves ( ) to control hydraulic cylinders ( ) or other hydraulically actuated machinery units of the machinery installation and with pilot valves ( ) controlling the working valves. In order to avoid the pilot valves ( ) and working valves ( ) entering an unstable operating condition in the event of a falling off of pressure in the hydraulic fluid supply to the valves, and opening and closing in an uncontrollable and undesired manner, the pilot valves ( ) are attached to their own pressure medium supply ( ), separate or separable from the hydraulic fluid supply ( ) to the working valves ( ), so that pressure variations in the hydraulic fluid supply circuit do not affect the pressure medium for the switching of the working valves ( ), but the pressure in them is maintained largely constant.