Control valve lock for a vehicle air brake system

A control valve lock for a vehicle air brake system to secure air-operated parking brakes in an engaged locked position, said lock comprising a base member having means to secure said base member relative to a valve actuating rod of an air control valve of said air brake system, said base member having a first bore for receiving in sliding fit therein a connecting shaft of an actuating knob, means to secure said connecting shaft to said valve actuating rod, a second bore in said base member spaced adjacent said first bore for receiving in sliding fit therein a portion of a lock cylinder, a passage in said knob disposed for axial alignment with said second bore and permitting free passage of said lock cylinder therethrough and in close sliding fit with at least a portion of said lock cylinder, said base member having a web section between said first and second bore, a locking through bore in said web, a key operable locking dog having a locking end portion spring-biased to extend out of a side wall of said lock cylinder and into said locking through bore, a dog engaging bore in said connecting shaft of said actuating knob, said locking end portion of said locking dog extending into said dog engaging bore when said knob is in a retracted position to enable said parking brakes, said dog being retractable in said lock cylinder by a key whereby to retract said locking end portion of said dog to disconnect said knob to permit said parking brakes to be disabled.