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:
Feb. 03, 1987
Filed:
Jan. 28, 1985
William K Engel, Peoria, IL (US);
Stephen R Bogert, Kennewick, WA (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
Electro-hydraulic valve arrangements are useful in controlling a displacement control member of a variable displacement pump or motor. However, previous digital electro-hydraulic valves having brief pulse widths required special high speed solenoids to speed up the response time of the valve and resulted in increased cost of the valve. The subject digital electro-hydraulic valve arrangement includes a pair of on/off solenoid actuated valves arranged in series so that a flow path is initiated by a first of the valves and is disrupted by the second valve. The response times of the valves are equal such that directing an electrical signal to the second valve during the response time of the first valve results in extremely brief pulse widths of the valve arrangement. Using two solenoid actuated valves in this manner permits the use of less costly solenoid valves to provide very brief pulse widths through the total valve arrangement.