04354713 is referenced by 2 patents and cites 4 patents.

The invention relates to a service brake system for towed vehicles and particularly to a service brake system for double trailer combinations and a metering relay valve therefor. According to the invention, a variable reaction amplifying relay valve, controlled by service brake control line pressure, meters reservoir pressure from the leading trailer to the service brake control line in the trailing trailer. Below a predetermined pressure, the metering relay valve provides an amplified pressure output relative to input. Above this predetermined point, the output pressure is substantially one-to-one.

Title
Dual area metering valve with variable reaction assembly
Application Number
6/206524
Publication Number
4354713
Application Date
November 13, 1980
Publication Date
October 19, 1982
Inventor
Norman Edwards
Florence
KY, US
Agent
James A Gabala
Ronald J LaPorte
Jon Carl Gealow
Assignee
Echlin
CT, US
IPC
B60T 15/02
View Original Source