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. 13, 1978
Filed:
Jun. 06, 1977
Lawrence F Schexnayder, Joliet, IL (US);
Caterpillar Tractor Co., Peoria, IL (US);
Abstract
A fluid system has first and second hydraulic jacks each having a load supporting end connected to a source of fluid through a control valve. First and second pilot operated valve assemblies are positioned between the control valve and the load supporting ends with each valve assembly having a first check valve positioned in a chamber and being movable between a first position at which communication between the associated load supporting end and the control valve is blocked and a second position at which the associated load supporting end is in fluid communication with the control valve. A second check valve is associated with the first check valve and is movable between a first position at which communication between the chamber and the control valve is blocked and a second position at which the chamber is in fluid communication with the control valve. A first piston is provided for urging the second check valve toward the first position and a second piston is provided for initially moving the second check valve to the second position and for subsequently moving the first check valve to the second position. A signal device senses the load pressure in the load supporting ends and delivers first and second control signals to the first piston of the respective first and second valve assemblies.