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:
Mar. 16, 1982
Filed:
Feb. 28, 1979
Malvin L Schubert, Kettering, OH (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A hydraulic pressure actuated power brake system having a hydraulic power booster with operating pressure on both sides of the power piston power wall. The booster is therefore hydraulic pressure suspended so that the hydraulic pump of the system need not be operating to maintain this pressure while the booster is inactive. An accumulator is also charged by this pressure to provide power brake booster operation for several booster actuations without recharging by the pump. When the pump is operating, a pilot valve which is sensitive to a drop in booster operating pressure will control charging or recharging the accumulator and booster from pressure generated by the pump to maintain a desired charge pressure. A pressure relief valve will also prevent overcharging of the accumulator and booster. A check valve prevents loss of booster operating pressure toward the pump outlet if the pump pressure falls below the charged pressure. A spool control valve in the booster modulates pressure on the downstream power piston side, returning fluid to the pump reservoir and creating a controlled pressure differential across the piston power wall to actuate the booster. A mechanical follow-through is provided for manual operation when booster operating pressure is depleted.