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. 20, 1998
Filed:
Nov. 04, 1996
Robert Koelzer, Kearney, MO (US);
Midland Brake, Inc., Kansas City, MO (US);
Abstract
A contaminant-ejecting, pneumatically-controlled brake booster valve is disclosed. The valve comprises an exhaust piston slidably mounted within the stem of a main piston of the valve, wherein the exhaust piston is actuated by supply air pressure to periodically open and close an exhaust passageway leading from the main piston chamber to an exhaust area. Pressurized supply air normally forces the exhaust piston in the exhaust passage blocking position thereby preventing the escape of control air through the exhaust passageway. When supply pressure is released (e.g. when the parking brake is applied), pressurized control air forces the exhaust piston upward, allowing some of the control air to escape through the exhaust passageway to the exhaust area. The escaping control air expels any moisture or other contaminants that may have accumulated in the main piston chamber. Additionally, a check valve is positioned in an orifice of the main piston. The check valve prevents control air from flowing through the orifice when control air is applied (i.e., when the brakes are applied) and allows delivery air to flow in the opposite direction when control air is released to equalize the pressure on both sides of the main piston and in the main piston chamber.