Patent · US Expired

Relay valve device

US4679865A · kind A · utility

2Cited by

7References

14Claims

0Family size

Assignee

WABCO Westinghouse Fahrzeugbremsen GmbH · DE

Inventors

Helmut Ulrich · Springe, DE
Peter Bartscher · Hannover, DE
Brian Shilton · Coalville, GB

Key dates

Filing date	Apr 9, 1986
Grant date	Jul 14, 1987
Priority date	—
Expiry date	Apr 9, 2006

Classification

Technology area (CPC B)Performing Operations; Transporting
CPC primaryB60T8/26
WIPO fieldTransport
WIPO sectorMechanical engineering

Abstract

A relay valve device having a first control surface and a second control surface. A shut-off device is located in the line feeding the control pressure into the second control surface throughout the period in which a signal pressure is present, and connecting the second control surface to atmosphere at other times. Thus, the relay valve device releases a greater pressure into a load circuit when actuated during effectiveness of the signal pressure than while the signal pressure is not effective. The shut-off device having a pressure relief valve with a switch-off device so that when the signal pressure is effective, the switch-off device switches OFF the pressure relief function of the pressure relief valve and so that when the signal pressure is not effective, the pressure relief valve is opened as long as the control pressure remains below the relief pressure and is closed when the control pressure moves above the relief pressure.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.