Railway vehicle penalty brake control system

Claim 1

A railway vehicle brake control system including braking means, an operator's brake valve device operative to provide service brake control pressure according to the selected position of an operating handle thereof in a brake application zone, and a source of fluid under pressure comprising: (a) a reservoir; (b) penalty control means for connecting said source of fluid under pressure to said reservoir in a first position and for venting said reservoir in a second position; (c) a first double check valve device via which either said service brake control pressure or said penalty brake control pressure is connected to said braking means; (d) a first pilot valve device including a control port subject to said reservoir fluid under pressure, an inlet connected to said source of fluid under pressure, an outlet connected to said first double check valve device, and an exhaust port, said first pilot valve device having an actuated position in which said inlet is connected to said outlet in response to said reservoir fluid under pressure being reduced below a first predetermined value to thereby provide penalty brake control pressure, and having a reset position in which said outlet is connected to said exhaust port in response to said reservoir fluid under pressure exceeding said first predetermined pressure to thereby exhaust said penalty brake control pressure; (e) suppression means for preventing operation of said first pilot valve device to said actuated position when said service brake control pressure exceeds said first predetermined value; and (f) interlock means for preventing operation of said first pilot valve device from said actuated position to said reset position when said penalty control means is in said second position comprising: (i) a second pilot valve device having a control port, an inlet, a first outlet, and a second outlet, said second pilot valve device being operable to an actuated position in response to said reservoir fluid under pressure being less than a second predetermined value, wherein said inlet thereof is connected to said second outlet thereof, and being operable to a reset position in response to said reservoir fluid under pressure exceeding said second predetermined value, wherein said inlet thereof is connected to said first outlet thereof; (ii) a first conduit between said reservoir and said control port of said second pilot valve device; (iii) a second conduit between said first conduit and said inlet of said second pilot valve device; and (iv) a third conduit between said brake valve device and said first double check valve device having said service brake control pressure, said reservoir fluid under pressure being exhausted via said brake valve device when said service brake control pressure is less than said reservoir fluid under pressure, whereby said second pilot valve is prevented from being operated to said reset position until said service brake control pressure exceeds said second predetermined value.