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. 30, 2004
Filed:
Aug. 29, 2002
Peter Schlüter, Kammerforst, DE;
Lucas Varity GmbH, , DE;
Abstract
A vacuum brake booster comprises a vacuum chamber and a working chamber which is separated in a pressure-tight manner from the latter by a mobile wall. In order to obtain a pressure difference at the mobile wall, a control valve is provided which comprises a housing coupled in a force-transmitting manner to the mobile wall and a first valve seat, which is disposed in the housing and which, in co-operation with a first valve sealing member, controls the supply of atmospheric pressure or overpressure to the working chamber in response to the displacement of an input member, which is coupled to the first valve seat, of the brake booster in order to obtain a pressure difference at the mobile wall. The first valve seat is formed at a displaceable valve member which is coupled to the input member in the actuating direction of the brake booster. The control valve comprises a second valve seat which, in co-operation with the first valve sealing member, controls a connection between the vacuum chamber and the working chamber. In order to achieve emergency brake assistance (brake assistant function), the valve member is constantly subjected to the pressure prevailing in the working chamber at its rear side, which is turned towards the input member. After the displaceable valve member has exceeded a prefixed displacement in the actuating direction relative to the control valve housing, the valve member is subjected over at least a part of its front side, which lies opposite the rear side, to the pressure prevailing in the vacuum chamber. The pressure difference then acting on the displaceable valve member holds it in the position reached until pressure equalisation between the front side and the rear side of the displaceable valve member takes place. In order to disconnect the brake assistant function, a component which is coupled to the input member in the direction opposite to the actuating direction of the brake booster acts on the first valve sealing member and lifts it off the second valve seat after a prefixed displacement of the input member.