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. 27, 1980
Filed:
Apr. 19, 1978
Howard L Johnson, Joliet, IL (US);
Caterpillar Tractor Co., Peoria, IL (US);
Abstract
A hydraulic system including a hydraulic pump, a hydraulic motor having at least one port and a hydraulic reservoir. A main spool valve is interposed between the motor and the pump and reservoir and has a spool shiftable between positions connecting the pump to the port, connecting the reservoir to the port, and blocking fluid flow to or from the port. A single combination check and flow control valve is interposed between the main spool valve and the port. A fluid responsive surface opens the combination valve to permit relatively free flow of fluid therethrough when the spool is in the first mentioned position thereof. A pressure responsive surface and a control valve provides for partial opening of the combination valve to meter fluid flow therethrough when the spool is in the second position thereof. A spring is operative to close the combination valve to prevent fluid flow therethrough when the spool is in the last mentioned position thereof.