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:
Jan. 05, 1993
Filed:
Sep. 12, 1990
Sean Byrnes, Birmingham, GB;
Colin McDonald, Solihull, GB;
Ivan Mortimer, Solihull, GB;
Frank J Bagley, Solihull, GB;
Lucas Industries public limited company, Birmingham, GB;
Abstract
The present specification discloses a servo unit for use in a vehicle braking system, the servo unit comprising a housing within which a flexible diaphragm separates a vacuum pressure chamber from an atmospheric pressure chamber. An actuator rod assembly extends through the housing and includes a valve assembly having a valve control piston which has a laterally extending key, the key being engageable with a fixed stop in the housing to limit the movement of the valve control piston and cause a balance in the valve assembly between the vacuum and atmospheric pressure. A solenoid valve is also provided, the solenoid valve being controllable to either connect a flexible passage member extending around the actuator rod assembly across the vacuum pressure chamber between the housing and the diaphragm in the region of the valve assembly, to the vacuum pressure chamber, or to connect both the flexible passage member and a bypass leading from the solenoid valve to the atmospheric pressure chamber, to the atmosphere. The bypass incorporates a one-way valve.