Locking mechanism for a trailer door

Abstract

A door locking mechanism for use with a door having a door latch assembly and a stationary catch includes a locking rod movable between a locking position and a release position. In its locking position, the locking rod extends into aligned passages formed in a latch member and a stationary catch member of a door latch assembly, which are engaged with each other in a latched position to maintain the door in a closed position. This prevents disengagement of the latch member from the catch member, to prevent opening of the door. In its release position, the locking rod is withdrawn from at least the latch member passage, to enable the latch member to be disengaged from the catch member and to allow opening of the door. The locking rod is interconnected with a piston disposed within a cylinder. A spring urges the piston toward a position placing the locking rod in its locking position. Fluid pressure is selectively provided to the side of the piston opposite the spring, for selectively overcoming the biasing force of the spring and to move the piston to a position placing the locking rod in its release position. The locking mechanism can be advantageously used with a trailer having a pneumatic system, such that supply of pressurized air in the trailer's pneumatic system is communicated to the piston to place the locking rod in its release position whenever a source of air pressure exceeding a predetermined threshold is connected to the trailer's pneumatic system.