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. 19, 2007
Filed:
Sep. 15, 2006
Jeffrey E. Tipton, Gettysburg, PA (US);
David M. Danley, Hanover, PA (US);
Kenneth C. Giurlando, Lancaster, PA (US);
Jeffrey E. Tipton, Gettysburg, PA (US);
David M. Danley, Hanover, PA (US);
Kenneth C. Giurlando, Lancaster, PA (US);
R.H Sheppard Co., Inc., Hanover, PA (US);
Abstract
A control valve for a hydraulic power steering system includes a pair of flow circuits arranged in parallel. Each flow circuit includes an upstream and downstream flow orifices arranged in series. Each set of orifices defines between the orifices an intermediate pressure zone of the valve. Both orifices close together from a centered condition of the valve and fully close substantially together at a fully closed condition of the valve. The downstream orifice is larger than the upstream orifice when open to minimize the likelihood of cavitation and noise. An equalization passage fluidly connects both intermediate pressure zones to equalize pressure despite variations in orifice size due to manufacturing tolerances. The control valve includes a bypass passage in parallel with the flow circuits. A pressure relief valve in the control valve has a normally closed valving member in the bypass passage that opens the valve in the event of overpressure.