Patent ID: 6971723

Claim:
A release graduating proportioning valve for a rail car brake system having a brake pipe, a brake cylinder, and a load sensor valve for detecting an empty/loaded car condition, said release graduating proportioning valve comprising: a. a proportioning piston having a control volume communicating on a first side of said piston and a second volume communicating on a second side of said piston; b. said load sensor valve having an empty car setting in which said control volume is connected to atmosphere via said load sensor valve, and a loaded car setting in which said control volume is connected to said brake cylinder via said load sensor valve; c. a graduated release valve member interposed between said control volume and atmosphere, said graduated release valve member having an open position at which said control volume is connected to atmosphere via said graduated release valve member, said graduated release valve member having a closed position at which said graduated release valve member does not connect said control volume to atmosphere; and d. said graduated release valve being activated by movement of said proportioning piston.