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:
Aug. 07, 1979
Filed:
Oct. 03, 1977
Ralph D Porter, Euclid, OH (US);
Towmotor Corporation, Mentor, OH (US);
Abstract
A control system for a fluid pressure-actuated cylinder or the like includes a pump supplying fluid from a reservoir to a control valve which may be selectively operated to cause cylinder extension or retraction and to immobilize the cylinder at a selected position. A unidirectional flow device connects an accumulator to the flow passage between the control valve and cylinder to smooth pressure fluctuations which can otherwise occur when the control valve is closed and which can otherwise produce erratic cylinder motions. Means are provided to relieve excessive pressure in the accumulator, at times when the control valve is shifted to release fluid from the cylinder, without in the process causing unwanted cylinder drift from feedback of the fluid from the accumulator to the cylinder. The excess accumulator pressure is vented to the reservoir through a pilot-operated check valve which is responsive to the pressure differential across the unidirectional flow device in order to allow communication between the accumulator and the reservoir but only when the pressure in the passage between the control valve and cylinder is less than that in the accumulator by a predetermined amount.