Pilferage deterrent device for lading carrying vehicles, such as boxcars and the like

In combination with a lading carrying vehicle having a floor, side walls extending upwardly therefrom, end walls connecting said side walls together and a door opening in at least one of said walls, a door operable to open and close said door opening, primary locking means for said door, disposed adjacent the bottom of said door and manually operable to lock the door closed, the improvement comprising;

• secondary locking means disposed above the primary locking means and operable by door closing movement independently of said primary locking means and comprising a keeper, a latch freely pivoted on said door in position to engage said keeper upon closing movement of the door, said latch extending parallel to the outer surface of the door and pivoted thereto eccentric of its center, to bias said latch into locking engagement with said keeper by gravity upon door closing movement, the end of said latch engageable with said keeper having an inclined strike surface camming said latch into position to have locking engagement with said keeper upon door closing movement and having a vertical latching surface along which the latch drops by gravity, a release member having a counter weight thereon, pivot means mounting said release member for movement about an axis parallel to the axis to pivotal movement of said latch, disposed rearwardly of and above the axis of pivotal movement of said latch, housing means enclosing said secondary latch and the lower portion of said release member and forming mountings for the pivots for said secondary latch and said release member wherein said release member is the sole means of camming said latch to an unlatching position and being accesssible only from a top portion of said housing means, and said latch having a rear upwardly facing face converging toward its lower end, and terminating into a step, and said release member having an undersurface extending along the converging surface of said latch when the latch is locked, to accommodate a reduced end of said release member to engage the step on said latch and hold said latch in said unlatching position, and means to automatically release said latch from said unlatching position including an angled surface carried on said latch and arranged to contact said keeper to cam said latch upward over said keeper upon movement of said door toward on open position and to concurrently disengage the step on said latch from said reduced end of said release member, whereupon said counter weight is effective to swing said release member free of said latch, whereby the latch will be repositioned by gravity to engage said keeper upon subsequent closing movement of the door.