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. 02, 1988
Filed:
Mar. 20, 1987
John M Graham, San Mateo, CA (US);
Other;
Abstract
A mechanical emergency and parking brake system, for vehicles of the type having a power steering pump, includes a check valve having an input port coupled to the pump outlet and an output port coupled to hydraulically deactuated spring brakes through brake lines. A pilot check valve has its inlet port coupled to the input port of the check valve and an output or return port coupled to the power steering gear. The pilot port of the pilot check valve is coupled to the output port of the check valve so that the pilot check valve opens only when the pressure at the output port of the check valve is above a chosen pressure. This allows hydraulic fluid to flow from the pump, through the pilot check valve, through the power steering gear and to the reservoir. To reapply the brakes, the operator actuates a valve which disconnects the brake ports from the output port of the check valve and connects the brake lines to the reservoir. This occurs when the operator wishes to set the brakes when stopped or in emergency situations. If desired, a pressure release valve can be fluidly connected to the output port of the check valve to limit the pressure at the output port.