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:
May. 24, 1977
Filed:
May. 01, 1975
Lawrence F Schexnayder, Joliet, IL (US);
Wayne A Peterson, Washington, IL (US);
Caterpillar Tractor Co., Peoria, IL (US);
Abstract
A pilot operated, control valve providing for two speed operation of a hydraulic jack in a first direction, the control valve including centering spring means for resisting movement of its spool in either direction and additional spring means for resisting movement of the spool in the first direction in order to establish two operating positions of the spool corresponding to the two speeds of operation for the jack, the first operating speed being accomplished by communicating the rod end of the jack with a drain and simultaneously communicating a source of fluid under the pressure with a head end of the jack, the second operating speed being accomplished by communicating both ends of the jack with the pump, a pilot valve being manually operable to regulate the control valve and having first and second springs to indicate the operating position of the control valve spool and the corresponding speed of operation for the jack in the first direction.