Valve for controlling pressure medium actuated brakes for railway and other vehicles

US3948571A · kind A · utility

Assignee

• Knorr-Bremse AG · DE

Inventors

• Erik Hefter · Eichenau, DE
• Hans Pollinger

Key dates

• Filing date: Nov 7, 1974
• Grant date: Apr 6, 1976
• Expiry date: Nov 7, 1994

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B60T15/12
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

A valve device for controlling pressure medium actuated brakes, particularly for railway vehicles, comprises a multi-stage valve to set one of a plurality of pressure stages. The valve has an axially displaceable stepped piston having a plurality of annular radial surfaces with a predetermined surface area ratio to each other. The surfaces are subjected to the action of pressure medium through control valves separately or in combination in accordance with a selected pressure stage. The piston controls a double valve connected between a source of pressure medium and the brake which is supplied with pressure medium or vented in response to position of the double valve. The radial surfaces of the piston are subjected to a selected stage pressure against a constant force that is independent of the control pressure such that this axially applied force is in balance with the force exerted by the pressure of the pressure medium against the radial surfaces at every braking stage.