Brake system with integrated car load compensating arrangement

A load compensating brake system for a railway car truck assembly, said brake assembly comprising:

• (a) first and second brake beams interposed between a bolster member and a respective one of a wheel and axle set so as to be in substantially parallel relationship with the bolster member, said first and second brake beams having brake shoes carried thereon adjacent each wheel tread of the wheel and axle set for engagement therewith when said brake beams are spread apart;
• (b) first and second transfer levers pivotally-connected, respectively, at a point intermediate each end thereof to said first and second brake beams, each said transfer lever forming first and second lever arms, an effective length of said first and second lever arms of at least one of said first and second transfer levers being dissimilar;
• (c) first force-transmitting means passing through a first opening of the bolster member for connection with said first lever arms of said first and second transfer levers;
• (e) second force-transmitting means passing through a second opening of the bolster member for connection with said second lever arms of said first and second transfer levers to effect rotation of said second transfer lever, whereby a force is exerted on said first and second brake beams, at said pivotal connection of said first and second transfer levers therewith, in opposite directions;
• (f) a fluid pressure operated control valve means which is connected to a source of a fluid pressure at an inlet port thereof and which is attached to one of the railway car, at least one of a pair side frames and a combination thereof for sensing a vertical position of one of the bolster member, a vertically movable portion of a railway car structure and a combination thereof, said vertical position corresponding to a load carried by the railway car, said fluid pressure operated control valve means further generating a first fluid pressure control signal at a first outlet port when said vertical position defining an empty load carried by the railway car and generating a combination of said first fluid pressure control signal at said first outlet port and a second fluid pressure control signal at a second outlet port when said vertical position defining a load greater than said empty load carried by the railway car, said first and said second outlet ports being in fluid communication with said inlet port;
• and
• (g) an actuating means disposed within said first force-transmitting means for effecting rotation of said first transfer lever, said actuating means engageable with a predetermined portion of said control means and selectively responsive to said first control signal to generate a first braking force and to combination of said first and said second control signals to generate a second braking force.

In a railway car mounted brake assembly having a brake actuator, a slack adjuster and a pair of brake beams mounted on each truck assembly of said railway car, said brake beams being actuated by said brake actuator via a series of levers and linkages, each of said brake beams having a brake head at each end thereof, each of said brake heads carrying a brake shoe thereon positioned for engagement with a respective one a respective railway vehicle wheel during a brake application, the improvement comprising:

• (a) a fluid pressure operated control valve means which is connected to a source of a fluid pressure at an inlet port thereof and which is attached to one of said railway car, at least one of said truck assemblies and a combination thereof for sensing a vertical position of one of such vertically movable portion of at least one of said truck assemblies, a vertically movable portion of said railway car structure and a combination thereof, said vertical position defining a load carried by said railway car, said control means further generating a first fluid pressure control signal at a first outlet port when said vertical position defining an empty load carried by said railway car and generating a combination of said first fluid pressure control signal at said first outlet port and a second fluid pressure control signal at a second outlet port when said vertical position defining a load greater than said empty load carried by said railway car, said first and said second outlet ports being in fluid communication with said inlet port;
• and
• (b) said brake actuator responsive to said first fluid pressure control signal to generate a first braking force associated with said empty load and to said combination of said first and said second fluid pressure control signals to generate a second braking force associated with said load greater than said empty load carried by said railway car and respectively apply one of said first braking force and said second braking force to each wheel of at least one of said truck assemblies.