Locking mechanism for a trailer door

A trailer door locking mechanism, comprising:

• a trailer including a door movable between an open position and a closed position;
• a floor adjacent the trailer door;
• and support structure for supporting the floor;
• a door latch assembly including a stationary catch member mounted to the trailer and a latch member mounted to the door, wherein the latch member is movable between a latched position in which the latch member is engaged with the catch member for maintaining the door in its closed position and a release position in which the latch member is disengaged from the catch member for enabling movement of the door to its open position;
• and
• a lock member movably mounted to the trailer, wherein the lock member is movable between a locking position in which the lock member is engaged with the latch member when the latch member is in its latched position for preventing movement of the latch member away from its latched position, and a release position in which the lock member is moved out of engagement with the latch member for enabling movement of the latch member away from its latched position, wherein the lock member comprises a locking rod movably mounted to the trailer, wherein the locking rod is mounted to the trailer support structure below the floor, and wherein the catch and the latch member include passages in alignment with each other when the latch member is in its latched position, wherein the locking rod in its locking position extends through the catch member passage and into the latch member passage, and in its release position is withdrawn from the latch member passage.

A method of locking a door in a closed position, wherein the door includes a movable latch member engaged with a stationary catch member when the door is in its closed position, comprising the steps of:

• mounting a movable locking rod adjacent the door for movement between a locking position in which the locking rod is engaged with the latch member and a release position in which the locking rod is disengaged from the latch member;
• forming passages in the catch member and the latch member such that the passages are in alignment with each other when the latch member is engaged with the catch member so as to maintain the door in its closed position;
• selectively engaging the locking rod with the latch member when the latch member is engaged with the stationary catch member to retain the latch member in engagement with the catch member;
• and
• selectively releasing engagement of the locking rod with the latch member to enable disengagement of the latch member from the catch member, wherein the steps of selectively engaging the locking rod with the latch member and selectively releasing engagement of the locking rod with the latch member are carried out by operating mechanism including a piston with which the locking rod is interconnected, a spring acting against the piston for urging the locking rod toward its locking position, and a pressurized fluid system in which pressurized fluid is selectively exposed to the piston to overcome the spring force and forcing the piston to move within the housing so as to place the locking rod in its release position.