US 4,830,437 AGranted

Brake assurance circuit to preserve proper locomotive operting status

AssigneeAmerican Standard Inc.

InventorSteven C. Rumsey

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Abstract

A brake assurance circuit via which a magnet valve device is deenergized to exhaust brake pipe pressure independently of the locomotive brake valve device in order to apply braking any time the proper operating status of the locomotive brake valve is changed after the locomotive is underway. A pressure switch responsive to the cut-in and cut-out setting of the manual selector valve associated with the brake valve senses the locomotive status and connects one of two possible circuits to the magnet valve device in parallel with a primary circuit having a speed responsive switch. Once locomotive movement is underway, the primary circuit drops out and the effective circuits selected by the pressure switch maintains the magnet valve energized provided the selected pressure switch setting is not changed. Should the pressure switch setting be changed, all power is cut off from the magnet valve and cannot be reapplied until the locomotive comes to a complete halt to allow the speed responsive switch to reset and restore power via the primary circuit.

A brake assurance circuit for a locomotive having a brake pipe (,brake control means operative) in which fluid under pressure is carried for controlling the brakes of a train in response to variations of fluid pressure effective in said brake pipe, a (locomotive) brake valve device via which said variation of said brake pipe fluid pressure is controlled, (flow control valve means via which said brake pipe fluid under pressure is supplied and exhausted under control of said brake valve device, and) selector valve means having a (normal) cut-in position (in which said flow control valve means is open) and a cut-out position (in which said flow control valve means is closed), and brake pipe cut-off valve means for connecting said brake pipe fluid under pressure to said brake valve device when said selector valve means is set in said cut-in position and for interrupting said connection when said selector valve means is set in said cut-out position, said brake assurance circuit comprising:

(a) a source of power;
(b) a first circuit to which said source of power is connected;
(c) a second circuit (to which said source of power is) connected in parallel with said first circuit, said second circuit having first and second branches in parallel via which said source of power is connected to said second circuit;
(d) exhaust means connected to said first and second circuits for exhausting the fluid under pressure in said brake pipe independently of said brake valve device when said exhausting means is deenergized;
(e) switch means for connecting current from said source of power to said second circuit via either one of said first (and) or second branches thereof depending upon said selector valve means being set in said cut-in or cut-out position;
and
(f) means for interrupting current in said first circuit and in the other of said first and second branches of said second circuit during said movement of said locomotive, whereby repositioning said selector valve means during said movement of said locomotive interrupts current in said one of said first and second branches to effect said deenergization of said exhausting means.

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Abstract

Claims16