Patent ID: 6095621
Filing Date: 2000-08-01
Classification: B60T

Abstract:
A truck control unit to perform a brake load weigh function on a truck of a rail vehicle, such rail vehicle including a controller unit for controlling service braking of wheels on such truck, said truck control unit comprising:(a) a pressure limiting valve connected to a primary source of pressure for limiting pressure received therefrom to a control pressure capable of initiating an emergency application of brakes on such truck when such rail vehicle is maximally loaded;(b) a relay valve having a supply port connected to such primary source of pressure, an output port connected to a brake cylinder of such truck, a control port for receiving a brake control pressure and an exhaust port from which to vent such brake cylinder, said relay valve for providing, in response to said brake control pressure at said control port, a corresponding pressure to such brake cylinder thereby causing an application of such brakes on such truck;(c) an application valve for conveying pressure received from said pressure limiting valve to said control port of said relay valve when said application valve is open;(d) a release valve for exhausting pressure received from said control port of said relay valve when said release valve is open;(e) a first transducer for converting pressure at said control port to a first feedback signal indicative of pressure at said control port of said relay valve;(f) a second transducer for converting pressure received from a load sensing system to a second feedback signal indicative of a load borne by such truck;(g) a means for electronically compensating for such load borne by such truck during braking by selectively opening and closing said application and release valves, according to predetermined criteria using said first and second feedback signals, thereby controlling a magnitude of said brake control pressure received by said control port of said relay valve; and(h) a means for granting said load compensation means exclusive control over said application and release valves such that (i) said granting means responds to an indication of an emergency by disconnecting such controller unit from said application and release valves thereby giving said load compensation means exclusive control of said application and release valves whereby said load compensation means compensates for such load borne by such truck during emergency braking and (ii) said granting means responds to an indication of a non-emergency by connecting such controller unit to said application and release valves by which such service braking on such truck is normally controlled with said load compensation means still enabled to compensate for such load borne by such truck during such service braking.