Rail car coupler interlock

In a railroad coupler system for railroad cars utilizing a compressed air brake system wherein the coupler includes a body having a recess defined therein for receiving a coupler knuckle head, a knuckle pivotally mounted upon said body pivotal between open and closed positions with respect to said recess, a locking member mounted upon said body selectively cooperating with said knuckle movable between knuckle locking and knuckle unlocking positions, manual means selectively translating said locking member between knuckle locking and knuckle unlocking positions, the improvement comprising, safety means mounted upon the body selectively engaging the locking member to control movement of the locking member from the locking position to the unlocking position, said safety means comprising an expansible chamber motor mounted upon the coupler body, a piston within said motor having a pressure face and a rod face, a rod affixed to said piston extending from said rod face and having an outer end projecting from said motor toward the locking member, an air supply conduit communicating with said motor and piston pressure face, a compression spring within said motor engaging said piston rod face, valve means within the compressed air brake system controlling air flow therethrough positionable between open and closed positions and in communication with said air supply conduit whereby closing of said valve means depressurizes said motor permitting said spring to retract said rod and opening of said valve means pressurizes said motor to extend said rod, and a rod receiving recess defined upon the locking member and aligning with said rod upon the locking member being in the knuckle locking position to receive said rod outer end.