A fluid brake control system is disclosed having an improved emergency application and stability control device for use in association with a brake control pipe, emergency and auxiliary fluid reservoirs, a first quick action chamber, a brake cylinder, and emergency and service control valves. An improved emergency application and stability control valve is provided comprising a housing containing a differential abutment subject to actuation axially by differences in fluid pressures in respective brake pipe pressure and quick action control pressure chambers on opposite sides of the abutment. The control device has at least one ball poppet type valve on each side of the abutment that is spring biased toward a closed position and has an operating push rod longitudinally disposed between the associated valve and the abutment. The poppet valve on one side of the abutment is opened by movement of the abutment in one direction for permitting application of fluid from the emergency reservoir to the brake cylinder. The poppet valve on the other side of the abutment is opened by movement of the abutment in the opposite direction to permit charging of the first quick action chamber at a controlled rate from the brake pipe. A stabilizing spring is provided in the brake pipe pressure chamber biasing the abutment normally in a direction to close the poppet valve on said one side of the abutment and to open the poppet valve on the other side of the abutment.
An upgraded railway freight car brake control valve device comprises a novel emergency valve portion that embodies therein a plurality of simple and inexpensive poppet valves that replace yet perform the same functions heretofore performed by more expensive slide type valves which slide valves, and the flat seats upon which they slide as they are shifted from one position to another, in their manufacture require a considerable amount of accurate machining thus increasing the cost of the valve device of which they are an important part.
A fluid brake control system is disclosed for governing application and release of brakes of an interchange vehicle having a brake control pipe, an auxiliary fluid reservoir, a fluid brake cylinder, and a brake control device sensing changes in fluid pressure in the brake pipe for at times governing application of fluid to the brake cylinder from the auxiliary reservoir and at other times for releasing fluid from the brake cylinder. Additional first and second volume chambers are provided that are proportionally smaller in volume than the auxiliary reservoir and brake cylinder displacement volumes respectively. Valve governed passageways are provided for normally charging the first volume chamber from the brake pipe and for preventing fluid flow from the auxiliary reservoir to the first volume chamber. The second volume chamber is charged from the first volume chamber upon sensing a reduction of pressure in the brake pipe at a rate to reduce pressure in the first volume chamber proportional to a service rate of reduction in the brake pipe, and relay control apparatus is provided for sensing a difference in fluid pressure between the brake cylinder pressure and pressure in the second volume chamber for governing the flow of fluid from the auxiliary reservoir to the brake cylinder. An emergency application is obtained by the use of sequenced proportioning valves wherein the brake cylinder is pressurized first from the auxiliary reservoir and then from an emergency reservoir. Apparatus is provided by which the second volume chamber can have its effective volume varied in accordance with the weight of the vehicle.
A railway freight car brake control valve device comprises a novel emergency valve portion that embodies therein a plurality of simple and inexpensive diaphragm-type valves certain of which are subject on their respective opposite sides to brake pipe pressure and quick action chamber pressure. The construction and arrangement of these diaphragm-type valves are such that a service rate of reduction of brake pipe pressure enables flow of fluid under pressure from the quick action chamber to the brake pipe at a service rate, and an emergency rate of reduction of brake pipe pressure enables one of these diaphragm-type valves to effect the supply of fluid under pressure from the quick action chamber to a brake pipe vent valve device the resulting operation of which vents fluid under pressure from the brake pipe to atmosphere at an emergency rate to thereby cause an emergency brake application.
