Security system for cargo trailers

Abstract

A cargo transportation device has a container including a cargo door accessible from the outside for closing the container and being movable from an open position to a closed position. A security system is provided that includes a latching device on the inside of the container, the latching device having a latch, a screw for moving the latch between an open position and a closed position, and a rotary motor for turning the screw. The security system has a latch receiving device, adapted to receive the latch, on the inside of the container. A controller operates a motor to turn a screw in one direction and thereby moves the latch from its unlocked position to its locked position. The controller also can operate the motor to turn the screw in the direction opposite of said one direction thereby moving the latch from its locked position in the latch receiving device to its unlocked position.

1 . A method of operating a security system for a cargo container including a cargo door, a latch, and an electronic controller configured to control movement of the latch, the method comprising: 
 monitoring the cargo door to detect a change in the cargo door's position;    monitoring the latch to detect a change in the latch's position;    determining whether the latch or the cargo door changed position;    determining whether user input regarding the position of the cargo door or the latch is received within a predetermined time period; and    moving the latch to a first position in response to either the latch or the door changing position and a failure to receive user input, within a predetermined time period, regarding the position of the cargo door or the latch.    
   
   
       2 . The method of  claim 1 , wherein the step of monitoring the cargo door comprises monitoring the cargo door to detect when the cargo door moves to a closed position.  
   
   
       3 . The method of  claim 2 , wherein the step of moving the latch comprises moving the latch to a locked position in response to the cargo door moving to the closed position, and wherein the user input comprises a command from the user to move the latch to the closed position.  
   
   
       4 . The method of  claim 1 , wherein the step of monitoring the latch comprises monitoring the latch to detect when the latch moves to an unlocked position.  
   
   
       5 . The method of  claim 4 , wherein the step of moving the latch comprises moving the latch to a locked position in response to the latch moving to an unlocked position, and wherein the failure to receive user input comprises failing to detect that the door is moved to an open position.  
   
   
       6 . A method comprising: 
 positioning a security system, including a latch and an electronic controller configured to move the latch, in a cargo container having a cargo door;    storing a number of permitted attempts to move the latch to a first position;    receiving a request to move the latch to the first position;    determining whether a number of previous attempts to move the latch to the first position is less than the number of permitted attempts;    attempting to move the latch to the first position if the number of previous attempts is less than the number of permitted attempts.    
   
   
       7 . The method of  claim 6 , wherein the steps of attempting to move the latch comprises moving the latch toward a locked position.  
   
   
       8 . The method of  claim 6 , further comprising: 
 moving the latch to a second position if the latch does not reach the first position.    
   
   
       9 . The method of  claim 8 , wherein the step of moving the latch to the second position comprises moving the latch to an unlocked position.  
   
   
       10 . The method of  claim 8 , further comprising: 
 incrementing the number of previous attempts.    
   
   
       11 . The method of  claim 8 , further comprising: 
 setting the number of attempts to zero if the latch is successfully moved from the first position to the second position or from the second position to the first position.    
   
   
       12 . A method comprising: 
 positioning a security system, including a latch and an electronic controller configured to move the latch, in a cargo container having a cargo door;    receiving a request to move the latch to a first position;    determining whether the door is in a first state;    if the door is in the first state, then the moving the latch to the first position; and    if the door is not in the first state, then not moving the latch to the first position.    
   
   
       13 . The method of  claim 12 , wherein the step of receiving comprises receiving a request to move the latch to a locked position.  
   
   
       14 . The method of  claim 13 , wherein the step of verifying comprises verifying that the door is closed.  
   
   
       15 . The method of  claim 14 , further comprising: 
 moving the latch to the locked position if the doors is closed.    
   
   
       16 . The method of  claim 15 , further comprising: 
 receiving a command indicating that the latch can be moved to the locked position if the door is open,    moving the latch to the locked position if the door is open.    
   
   
       17 . A method comprising: 
 positioning a security system, including a latch and an electronic controller configured to move the latch, in a cargo container having a cargo door wherein the electronic controller is configured to move the latch to a first position in response to receipt of a signal over a first communication channel and to move the latch to a second position in response to receipt of a signal over a second communication channel;    receiving a data transmission from a key fob over a third communication channel;    preventing movement of the latch in response to receipt of a signal over the first channel or the second channel in response to receipt of the data transmission.    
   
   
       18 . The method of  claim 17 , wherein the step of receiving the data transmission comprises receiving a single signal.  
   
   
       19 . The method of  claim 17 , wherein the step of receiving the data transmission comprises receiving a plurality of signals.  
   
   
       20 . The method of  claim 17 , further comprising: 
 receiving another data transmission from the key fob over the third channel, and in response to receipt of the other data transmission, permitting movement of the latch in response to receipt of a signal over the first channel or the second channel.