Fluid brake control system

Abstract

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.

What is claimed is: 
     
       1. A fluid brake control system for a vehicle having a brake control pipe, emergency and auxiliary fluid reservoirs, a first quick action chamber, a brake cylinder, and service and emergency control valves wherein an improved emergency application and stability control device is provided comprising: a. a housing containing a differential abutment subject to actuation axially by differences in fluid pressures in brake pipe pressure and quick action control pressure chambers on opposite sides of the abutment,   b. at least one poppet type valve means disposed in the housing on each of said opposite sides of the abutment and located partly in each of said brake pipe pressure chamber and said quick action control pressure chamber spring biased toward a closed position and having an operating push rod longitudinally disposed between the associated valve means and the abutment,   c. the poppet valve means on one side of the abutment being opened by movement of the abutment in one direction and having means for permitting application of fluid from the emergency reservoir to the brake cylinder when this valve is opened,   d. the poppet valve means on the other side of the abutment being opened by movement of the abutment in the opposite direction and having means to permit charging of the first quick action chamber at a controlled rate from the brake pipe when this valve is opened, and   e. a stabilizing spring in the brake pipe pressure chamber biasing the abutment in a direction to normally open the poppet valve means on the other side of the abutment.   
     
     
       2. A fluid brake control system according to claim 1 wherein the control device has a second poppet type valve means on each side of the abutment, a bridge in each of the control pressure chambers subject to actuation by the abutment at an intermediate point, and push rods disposed longitudinally between the valve means and ends of the bridges on the same sides of the abutment for causing actuation of the valve means in accordance with movement of the abutment. 
     
     
       3. A fluid brake control system according to claim 2 wherein fluid pressure means is provided responsive to the opening of the second poppet valve means on said one side of the abutment for opening a vent valve to vent fluid from the brake pipe. 
     
     
       4. A fluid brake control system according to claim 3 wherein means responsive to the opening of the second poppet valve means on said other side of the abutment is provided for venting the first quick action chamber at a controlled rate. 
     
     
       5. A fluid brake control system according to claim 4 wherein quick service valve means is provided for selectively venting fluid from the first quick action chamber and means including the second poppet valve means on the other side of the abutment is provided for selectively permitting venting of the first quick action chamber through the quick service valve means, dependent upon whether brake pipe pressure is reduced at a service or an emergency rate. 
     
     
       6. A fluid brake control system according to claim 1 wherein inshot valve means is provided for governing the rate of flow of fluid to the brake cylinder from the reservoirs and double-acting check valve means is provided to permit a balancing fluid pressure to flow to the inshot valve during a service brake application, said poppet valve means on said one side of the abutment being effective when opened by movement of the abutment upon sensing an emergency application rate of reduction of the brake pipe to actuate the double acting check valve and prevent balancing pressure from being applied to the inshot valve means. 
     
     
       7. A fluid brake control system according to claim 6 wherein the check valve means has one inlet port, one outlet port, and a third port that is an inlet port for service brake application and an outlet port for emergency brake application, and means is provided for passage of fluid from the emergency reservoir to the brake cylinder during emergency application through said poppet valve means on said one side of the abutment and through the inlet and third ports of the check valve means in series. .Iadd. 8. Fluid brake control apparatus for a railway vehicle having a brake control pipe, emergency and auxiliary fluid reservoirs, a quick action chamber, a brake cylinder, and service and emergency control valves, wherein an emergency application control device is provided comprising: a. a housing containing a differential abutment subject to actuation by differences in brake pipe and quick action chamber pressures acting on opposite sides of the abutment,   b. first and second valve means each of the poppet type and each having relatively movable seat and closure elements, each of said first and second valve means having at least one of its said seat and closure elements operatively connected to the abutment,   c. both said first and second valve means being opened by movement of said abutment in response to a decrease in brake fluid pressure relative to quick action chamber pressure occurring at a rate indicative of an emergency brake application,   d. means responsive to the opening of said first valve means for applying fluid from said emergency reservoir to the brake cylinder, and   e. means responsive to the opening of said second valve means for venting said quick action chamber at a controlled rate to ensure that the pressure in said quick action chamber continues to exceed that in said brake pipe and effective on one side of said abutment for at least a predetermined time to thereby prevent closure of said first valve means throughout said predetermined time. .Iaddend.