Patent Publication Number: US-2004055345-A1

Title: Door lock system for trailers and cargo containers

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
     [0001] This application claims the benefit of U.S. Provisional Application No. 60/413,503 filed Sep. 24, 2002. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] A. Field of the Invention  
       [0003] The field of the present invention relates generally to devices for securing the doors of a trailer or cargo container so as to prevent unauthorized entry into the trailer or container. More specifically, this invention relates to trailer and container door locking devices utilizing a computer-controlled linear actuator to secure the doors and provide for coded entry therein. Even more specifically, this invention relates to such locking devices that provide for remote operation and reporting via wireless transmission.  
       [0004] B. Background  
       [0005] Many persons utilize trailers and cargo containers for various applications, including trailers and containers that are used to transport goods, vehicles, and other materials. Although the trailers and containers commonly used in the trucking and cargo industry are very expensive, the goods being transported therein, such as electronics or cars, can often far exceed the value of the trailer or container itself. While pulling a trailer or cargo container carrier, the truck driver often needs to leave the trailer or container unmanned at a specified location. In fact, cargo containers are often utilized as storage containers that are left at the same location for extended periods of time. All too often, unfortunately, thieves utilize the opportunity of a trailer or cargo container left alone, particularly if it is at a remote location, to steal the contents of the trailer or container. Once the thieves open the trailer or container doors, they will quickly remove its contents and leave the area. Due to the nature of the crime and the goods stored therein, it is often difficult for the owner of the goods to regain possession of his or her property.  
       [0006] In addition to carrying or storing general consumer goods, trailers and cargo containers are utilized all over the world to carry and/or store materials that are known to be desirable to terrorists, both domestic and foreign, and other individuals or groups that desire to harm others or acquire their property. These materials include explosive devices, chemicals, weapons, ammunition, parts for repairing weapons and materials for making or using explosives and weapons. Although some of this material is transported or stored under guarded conditions, much of it is not. Because of greater concern for national security and safety throughout the world, numerous governments, military, private companies and individuals are taking a more active role in addressing or regulating the security of trailers and cargo containers. Even trailers or containers carrying or storing items once thought to be relatively benign, such as those transporting or storing food goods, are now facing increased security concerns and regulations due to the realization that such items can be easily and effectively contaminated with chemical or biological matter than could harm large numbers of people.  
       [0007] In light of the increased security risks and governmental oversight, unauthorized entry into and theft from trailers is a major concern among those in the trucking and cargo container industry. As security devices become more complicated and more expensive, thieves become more sophisticated and more resourceful, making protection of an unmanned trailer or container very difficult and expensive. Devices have been developed that, when regularly and properly used, generally deter the would be thief from stealing a vehicle, such as an automobile or truck, in part because of the amount of time and effort it takes to remove or get around the theft deterrent device. An example of devices that have been generally successful at reducing theft of vehicles are the various steering wheel lock devices that provide a bar across the steering wheel, making movement of the steering wheel, and hence the vehicle, virtually impossible. While the steering wheel lock devices have worked well for, there exists a need for a device that prevents entry into a trailer or cargo container in order to protect the owner&#39;s investment in the goods stored therein and to prevent sensitive materials falling into the possession of dangerous individuals or groups.  
       [0008] To prevent the theft of materials from inside a trailer or cargo container left or stored at protected or unprotected locations, trailer and container owners typically use exterior mechanical locking devices, such as padlocks and the like, and seals that are designed to physically prevent entry into the trailer or container. As those in the trucking industry know, experience has proven that the devices currently in use can be overcome relatively easily by the determined and resourceful thief, particularly one with a good set of bolt cutters. In addition to being relatively easy to overcome, the devices are useless if the truck driver or container operator (i.e., a person having authority to open the container to remove the contents or conduct an inventory check) forgets to set the locks. Even when the driver or operator does set the lock or locks, problems can arise if the next authorized driver or operator does not have the correct key or combination and is forced to break the lock to gain entry into the trailer or container, thereby rendering the security system useless. In areas where a number of people may need access to the contents of a trailer or container, the ability to ensure that the right person has the necessary key or combination to gain entry into the trailer or container can be quite challenging.  
       [0009] In order to be able to find a stolen truck and hopefully find the goods or materials carried therein, some trucking companies utilize satellite tracking devices attached to the truck and/or trailer that enable the trucking company or law enforcement personnel to track the movement of the truck/trailer. Although the theft of cargo containers is relatively less common, it is possible to load them onto a truck or other vehicle. As such, some satellite systems are also configured to work with cargo containers. Unfortunately, most satellite systems are very expensive and can be relatively easily disabled (i.e., with a screwdriver and hammer) due to the vulnerability of the antenna assembly.  
       [0010] Although the various theft deterrent devices currently available have some ability to prevent theft of materials from inside a trailer or cargo container, they have disadvantages and limitations that prevent wide acceptance or effective theft deterrence. One of the most common problems with presently available trailer or container security devices is the need to rely on human operation to set or re-set the security device. What is needed, is an easy to use and effective theft deterrent or locking device that allows a trailer or container owner to quickly and securely lock the trailer or container door in order to prevent unauthorized entry into the trailer or container. The preferred locking device will automatically secure the door, without the need for the human element to set the lock, and maintain the door in a locked condition until such time as an authorized individual opens the door. The preferred device will facilitate wireless communication for reporting on the door status (i.e., locked/unlocked or open/closed) and remote operation of the locking mechanism.  
       SUMMARY OF THE INVENTION  
       [0011] The door lock for trailers and cargo containers of the present invention solves the problems identified above. That is to say, the present invention discloses a new and useful locking device that effectively prevents unauthorized entry through a trailer or container door. The door lock device of the present invention is adaptable to new and existing trailers and containers, is easy for the truck driver or container operator to engage and is difficult for the thief to overcome or disable. The door lock of the present invention automatically engages the locking system when the door is closed and maintains the lock in the locked condition until an authorized person enters the proper unlock code.  
       [0012] In one aspect of the door lock for trailers and cargo containers of the present invention, the door lock system comprises an electronic keypad on the exterior of the trailer or cargo container, a computerized controller unit in communication with the keypad, a linear actuator controlled by the controller unit to actuate a sliding bolt or other device into engagement with and actuator receiving mechanism, a position switch to indicate and transmit the open or closed position of the door, an antenna connected to radio in the controller unit and various connecting wiring. In one embodiment, a source of electric power, such as a battery suitable for recharging by the trailer electrical system, powers the controller unit and actuator. In the preferred embodiment, the controller unit and linear actuator are attached to back plate member that is mounted on the inside of the trailer or container door. The actuator receiving mechanism, which can be a hole located in a frame member, such as the header, is positioned and configured to receive the stainless steel bolt portion of the actuator mechanism. The position switch, which can be a reed switch having a pair of interacting magnets, one on the door frame and one on the locking mechanism or door, is used to indicate to the controller unit whether the door is in an open or closed position. If the position switch indicates an open door, the controller unit does not send a signal to the actuator to lock the door. The controller unit is configured to automatically lock the door, after a pre-set amount of time, upon receiving a signal from the position switch that the door is closed. Because the controller unit is configured to automatically activate the linear actuator after a preset elapsed time, it will relock the door even if the driver or operator forgets to set the lock. The door can be unlocked by entering the correct code on the keypad or by receiving a predetermined signal via wireless interface. The door lock system of the present invention allows the person exercising control over the contents of the trailer or container to prevent anyone, including the driver or other persons, from opening the door by limiting access to the code. The controller unit can also be configured to receive code changes, by utilizing appropriate security level clearances, that would modify the existing code to unlock the system if it were necessary because the code had been compromised or if the trailer was being sent to a different receiving party than was originally intended (as a result, requiring a different code for the new receiving party).  
       [0013] Accordingly, the primary objective of the present invention is to provide a door lock for trailers and cargo containers that provides the advantages described herein and overcomes the disadvantages and/or limitations associated with presently available door lock devices and systems.  
       [0014] It is also an important objective of the present invention to provide an easy to use and effective theft deterrent system that is difficult to overcome so as to prevent theft of materials from inside a trailer or cargo container.  
       [0015] It is also an important objective of the present invention to provide a door lock for trailers and cargo containers that utilizes a computer-controlled actuator to drive a sliding bolt into a frame member or receiver mounted to the frame of a trailer or cargo container when the door is closed or upon command by a user received through a keypad entry or over a wireless network.  
       [0016] It is also an important objective of the present invention to provide a door lock for trailers and cargo containers that is adaptable for new and retrofit installations at various locations on the doors of the trailer or cargo container.  
       [0017] It is also an important objective of the present invention to provide a door lock device for trailers and cargo containers that can interact with other locking systems to automatically lock the doors and maintain the doors in a locked condition until such time as the proper code is entered into the door lock system.  
       [0018] It is also an important objective of the present invention to provide a door lock for trailers and cargo containers that is useful for both trailers and cargo containers with or without their own source of power and for the swing and roll-up types of doors.  
       [0019] The above and other objectives of the present invention are explained in greater detail by reference to the attached figures and the description of the preferred embodiment which follows. As set forth herein, the present invention resides in the novel features of form, construction, mode of operation and combination of processes presently described and understood by the claims. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0020] In the drawings which illustrate the best modes presently contemplated for carrying out the present invention:  
     [0021]FIG. 1 is a front view of the door locking component of the door lock system of the present invention from inside a trailer or cargo container with the swing doors closed;  
     [0022]FIG. 2 is a side view of a preferred embodiment of the door locking system of the present invention;  
     [0023]FIG. 3 is a front view of the actuator mechanism and its related components mounted on the back plate member;  
     [0024]FIG. 4 is a front view of the actuator mechanism, controller unit and position switches of the door lock system of the present invention;  
     [0025]FIG. 5 is a front view of a keypad configured to operate with the door lock system of the present invention;  
     [0026]FIG. 6 is a isometric view of the front end of a trailer showing the placement of he keypad thereon;  
     [0027]FIG. 7 is a front view of a keypad having a visual representation of the locked and unlocked doors;  
     [0028]FIG. 8 is a front view of a keypad configured to be separate from the trailer and engageable with the door lock system when used to operate the controller unit; and  
     [0029]FIG. 9 is a front view of the door locking component of the door lock system configured for use with a roll-up door from inside a trailer or cargo container having the roll-up door closed.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0030] With reference to the figures where like elements have been given like numerical designations to facilitate the reader&#39;s understanding of the present invention, and particularly with reference to the embodiments of the present invention illustrated in the figures, the preferred embodiments of the present invention are set forth below. The enclosed figures and drawings are merely illustrative of the preferred embodiments and represent several different ways of configuring the present invention. Although specific components, materials, configurations and uses of the present invention are illustrated and set forth in this disclosure, it should be understood that a number of variations to the components and to the configuration of those components described herein and in the accompanying figures can be made without changing the scope and function of the invention set forth herein.  
     [0031] A preferred embodiment of the door lock system for trailers and cargo containers of the present invention, identified generally as  10  in the figures is configured to function with trailers or cargo containers, or other enclosed body, shown generally as  12  in FIG. 1 (hereinafter trailers, cargo containers and other enclosed bodies are collectively referred to as trailers). Such trailers  12  are commonly utilized in the trucking and storage industries to move and store numerous types of materials, including consumer goods and sensitive or dangerous materials. There are many different types of trailers  12  in use, many of which are configured to meet or exceed International Standards Organization (ISO) trailer/container requirements or other regulations pertaining to domestic trailer and/or cargo container configurations. In one configuration, trailers  12  have a pair of swing-type loading doors  14  and  16  mounted on a structural frame  18  having a plurality of frame members, including top member or header  20  supported by side members  22  and  24  above bottom member or threshold  26 . As shown in FIG. 9, trailer or cargo container  12  can be configured with a single roll-up door  28  that is rolled or slid upward at the rearward opening of trailer  12 . As shown in FIG. 1, which shows the view from inside trailer  12  with doors  14  and  16  closed, the door locking component  30  of door lock system  10  can be mounted on door  14  near header  20  to operatively engage header  20 . Alternatively, door locking component  30  can be mounted on door  14  at or near threshold  26  to operatively engage threshold  26 . In either configuration, door locking component  30  should be mounted generally near the center of header  20  or threshold  26  where doors  14  and  16  meet, as shown in FIG. 1. As shown, after door  16  is closed, door  14  closes to abut against the overlap plates  32  on door  16 . As shown in FIG. 9, door locking component has a different configuration to prevent unauthorized entry into trailer  12  having roll-up door  28 . In either configuration, as explained in more detail below, door lock system  10  is utilized with trailer  12  to prevent unauthorized entry into the interior storage compartment of trailer  12  through doors  14  and  16  or roll-up door  28 .  
     [0032] In a preferred embodiment of the door lock system  10  of the present invention, door locking component  30  primarily comprises an actuator mechanism  34  controlled by computerized controller unit  36  to drive sliding bolt  38  slidably disposed in tubular member  40 , all of which are mounted on or attached to back plate member  42 , as shown in FIG. 2. As set forth in more detail below, in the preferred embodiment of the door lock system  10 , controller unit  36  is operatively connected to antenna system  44 . A keypad  46  is utilized for accessing controller unit  36  to engage or disengage door lock system  10 , as shown generally in FIG. 2. In the preferred embodiment, actuator mechanism  34  is a electro-mechanical linear actuator having a main body  48  with a drive screw or other drive mechanism inside, a motor  50  to drive the drive mechanism and a gear box  52 , as shown in FIGS. 2 and 3. Although other actuating systems can be used, including hydraulic, pneumatic or solenoid-based actuating systems, these systems have certain well known operational and functional disadvantages that make the electro-mechanical type of actuator mechanism  34  the preferred actuator. The drive mechanism inside main body  48  actuates actuating rod  54 , which is coupled to sliding bolt  38  at collar  56  by first pin  58 . In the preferred embodiment, collar  56  is welded or otherwise joined to first end  38 a of sliding bolt  38 . First pin  58  is placed through holes in sliding bolt  38 , actuating rod  54  and collar  56  to couple these components together such that the actuation of actuating rod  54  by actuator mechanism  34  will cause sliding bolt  38  to move inside tubular member  40  along its longitudinal axis. In the preferred embodiment, first pin  58  is the type that cooperates with first spring clip  60 , best shown in FIG. 4, to releasably maintain first pin  58  engaged with actuating rod  54 , sliding bolt  38  and collar  54 . Second pin  62 , which in the preferred embodiment projects outwardly from a fixed position on back plate member  42 , engages a hole in base extension  64  to hold actuator mechanism  34  in place on back plate member  42 , as best shown in FIGS. 2 and 3. In the preferred embodiment, second spring clip  66 , best shown in FIG. 2, is utilized to releasably maintain the coupling of second pin  62  with base extension  64 .  
     [0033] As is known in the art, the typical linear actuator  34  has an actuating rod  54  that is threaded inside main body  48  to permit linear adjustment of the distance which actuating rod  54  extends. Use of first pin  58  prevents undesirable rotation of actuating rod  54 , which could cause actuating rod  54  to become unthreaded inside main body  48 . Use of spring clip  60  with first pin  58  allows a person who is inadvertently closed inside the locked trailer  12  to remove first pin  58  and, as explained more fully below, uncouple actuator mechanism  34  from the other components so the doors  14  and  16  can be opened. Use of second pin  62  further facilitates the removal of actuator mechanism  34  from back plate member  42  in case of a person stuck inside trailer  12 . In the embodiment shown in the drawings, a person inside locked trailer  12  would first remove second spring clip  66  from second pin  62  and pull actuator mechanism  34  at extension  64  away from back plate member  42  and off of second pin  62 . The person then could remove first spring clip  60  from first pin  58  and uncouple first pin  58  from actuating rod  54 , sliding bolt  38  and collar  56 . Actuator mechanism  34  could then be lowered to remove second end  38 b of sliding bolt  38  from engagement with header  20  (as explained below). To facilitate this operation, first spring clip  60  and second spring clip  66  can be of the quick-release type commonly utilized in various connecting operations.  
     [0034] As best shown in FIGS. 2 and 4, in the preferred embodiment of door lock system  10  of the present invention, controller unit  36  is mounted to the front side of back plate member  42 . Controller unit  36  has a housing  68  that encloses appropriate computer circuitry and componentry, shown as integrated circuit board  70  on FIG. 4, for controller unit  36  to read and analyze incoming signals from various components of door lock system  10  so as to operate actuator mechanism  34  to lock or unlock door lock system  10 . Preferably, housing  68  sealably encloses the components inside controller unit  36  to prevent intrusion of water or other fluids that could damage the computer circuitry and componentry  70  (i.e., integrated circuit) and other components therein. Controller unit  36  is in communication with keypad  46  such that operation of keypad  46  can control the locking and unlocking by door locking component  30 . In the embodiment shown in the figures, keypad  46  connects to controller unit  36  by keypad wire  72 . Other known mechanisms of connecting keypad  46  to controller unit  36  can be utilized. In the preferred embodiment, controller unit  36  also encloses a radio or other communication device, shown as  74  in FIG. 4, to permit wireless radio communication with a remote central office (i.e., via a cellular communications network or satellite connection) or even to a hand-held radio device placed near trailer  12 . In one embodiment, the communication device  74  is a 900 MHz, 32 bit encryption radio. The preferred embodiment of the present invention  10  for use with trailers, as opposed to cargo containers, also has a rechargeable battery  76  located inside controller unit  36 , preferably in a sealed compartment so it cannot damage the other components, and operatively connected to the electrical system of trailer  12 , by battery wire  78  in FIG. 2, to allow recharging of battery  76  by the electrical system of trailer  12  or the vehicle pulling trailer  12 . As shown in FIGS. 1 and 4, housing  68  will generally need to be somewhat larger size to accommodate battery  76  therein. Without battery  76 , controller unit  36  is typically the same width as back plate member  42 . The use of battery  76  will generally not be preferred when door lock system  10  is used with cargo containers or like containers due to the lack of electrical system or other mechanism for recharging battery  76 . In some situations, it may be possible to utilize solar panels or similar devices to create a recharging system to allow use of battery  76  in door lock system  10  when used with cargo containers and the like.  
     [0035] On the exterior of trailer  12  is placed electronic keypad  46 , which is shown in detail in FIG. 5, to allow authorized persons to lock or unlock door lock system  10  to open doors  14  and  16 . As stated above, keypad can connect to controller unit  36  via keypad wire  72  and be located on door  14 , as shown in FIG. 1, or other places at the rear of trailer  12 . Alternatively, keypad  46  can be placed at the front end  80  of trailer  12 , as shown in FIG. 6. This location may be particularly beneficial if door lock system  10  is used in conjunction with a brake lock system  82  for preventing unauthorized movement of trailer  12 . Keypad  46  comprises a keypad case  84  having a plurality of function keys  86 , such as the numeric and command keys shown in FIG. 5, sufficient for secure operation of controller unit  36 . In the preferred embodiment, keypad  46  is securely mounted to trailer  12  to prevent keypad  46  falling off during transit or being easily removed by unauthorized persons. If desired, keypad  46  can be configured with a visual representation  88  of the locked/unlocked status of the various doors on trailer  12 , as shown in FIG. 7. Different colored lights can be utilized to signal locked and unlocked conditions of the various doors. This could be particularly important when trailer  12  is utilized to transport different types (i.e., frozen, refrigerated and dry goods) of food materials. Once loaded into different compartments that are securely separated inside trailer  12 , governmental regulations prohibit more than one door being open at any given time to avoid contamination of the food materials. Failure to abide by these regulations can result in significant fines and the intended recipient refusing to take the food materials. The keypad  46  of FIG. 7 lets the user know at a glance which, if any, doors are unlocked. If placed at front end  80  of trailer  12 , the keypad  46  of FIG. 7 can be seen in the driver&#39;s rearview mirror while trailer  12  is in transit.  
     [0036] In another embodiment of keypad  46 , shown in FIG. 8, the keypad  46  can be a portable device that has cord  90  with connector  92  at the end thereof that is adapted to connect to a like-configured port (not shown) on trailer  12 . In another configuration, keypad case  84  can enclose a battery (not shown) to operate actuator mechanism  34 . This embodiment is particularly useful when door lock system  10  is utilized with a cargo container that does not have its own electrical system or is not connected to another electrical system so as to recharge battery  76  inside controller unit  36 . In yet another embodiment, keypad  46  can include a separate computer componentry to allow it to store and analyze data and a display panel to display that information. For instance, such a keypad  46  can be utilized for inventory purposes. Every time someone opens doors  14  and  16  to add material in trailer  12  or remove material from trailer  12 , he or she can enter the amount of material (i.e., ammunition or explosive devices) being removed from trailer  12 . In this manner, the inventory of material inside trailer  12  will be known, particularly to persons remote from trailer  12 , which can be accomplished by transmitting such information via a wireless network.  
     [0037] Antenna system  44 , shown in FIG. 2, is used to improve the reception for radio  74  located inside housing  68  of controller unit  36  so that door lock system  10  can be controlled or monitored remotely (i.e., at company headquarters, etc.). In the embodiment shown in FIG. 2, antenna system  44  comprises antenna rod  94  mounted on mounting box  96  by antenna adapter  98 . The components for antenna system  44  should be selected to operatively correspond to radio  74 . For instance, if radio  74  is a 900 MHz radio, then antenna system  44  should be a 900 MHz antenna so as to provide optimum performance for radio  74 . To utilize antenna system  44 , a hole  100  should be drilled or otherwise provided in door  14  to allow an antenna wire (not shown) to pass from antenna rod  94  to radio  74  in controller unit  36 . Antenna system  44  can be of the type that communicates with a GPS tracking unit located in the cab of a truck utilized to haul trailer  12 . Instead of utilizing antenna rod  94  and the other external components, antenna system  44  can be configured to be internal to keypad  46  and included in the keypad wire  72  that connects to controller unit  36 . In one configuration, antenna system  44  is a loop antenna disposed inside keypad  46  or, if signal strength is or will not be a problem, inside controller unit  36  itself.  
     [0038] The preferred embodiment of door lock system  10  of the present invention further comprises a position switch  102 , as shown in FIGS. 1 and 4, in communication with the computer circuitry  70  in controller unit  36  to indicate the open or closed position of door  14 . A variety of position switches  102  may be employed for communicating the position of door  14  to the integrated circuit  70  of controller unit  36 . As explained in more detail below, door lock system  10  of the present invention utilizes information pertaining to the position of door  14  to operate actuator mechanism  34  so as to operatively engage sliding bolt  38  with header  20 . In the preferred embodiment, position switch  102  is a reed switch having a first magnet  104  mounted to frame  18 , such as to header  20  or threshold  26  as the case may be, and a second magnet  106  mounted to door locking component  30 , such as on back plate member  42 , so as to swing open and close with door locking component  30  as door  14  is opened or closed. As is well known in the art, a magnetic field between magnets  104  and  106  is employed to open and close connections to leads of integrated circuit  70 . Other types of proximity types of switches can be used to determine the opened or closed position of door  14  to open or close a connection to integrated circuit  70 , including various traditional contact mechanisms, so as to cause controller unit  36  to operate actuator mechanism  34 . Although it is preferred that position switch  102  be located on or near door locking component  30 , position switch  102  could be located away from door locking component  30  (i.e., at threshold  26  if door locking component  30  at header  20 , or vice-versa).  
     [0039] In the preferred embodiment, back plate member  42  is made out of steel or other durable and strong material. Tubular member  40  can made from a steel tubular material and machine welded or otherwise fixed to back plate member  42 . Second pin  62  can extend from the back side of back plate member  42  through back plate member  42  to extend frontwardly, as shown if the figures. Housing  68  for controller unit  36  can be bolted, welded or otherwise attached to back plate member  42 . As stated above, main body  48  of actuator mechanism  34 , actuating rod  54 , collar  56  and sidling bolt  38  can be removably attached to second pin  62  and slidably received inside tubular member  40 . In one configuration, sliding bolt  38  is a ¾″ stainless steel bolt and tubular member  40  has an inside diameter of ⅞″ to allow sliding bolt  38  to be slidably disposed therein and to move with out substantial interference from tubular member  40 . To prevent door  14  from being opened, sliding bolt  38  is configured to engage a receptor  108  in or mounted to header  20  or threshold  26 . In the preferred embodiment, as shown in FIG. 2, receptor  108  is a hole drilled or otherwise provided in header  20  that is sized and configured to slidably receive sliding bolt  38  inside chamber  110  of the tubular frame  112  of header  20 , which can be a 4″ by 4″ square tubular member. In one configuration, the top of door locking component  30  is positioned approximately one inch below the bottom of header  20 , by mounting back plate member  42  to door  14 , and sliding bolt  38  has an actuating distance of approximately two inches, such that approximately one inch of second end  38   b  of sliding bolt  38  is received inside chamber  110  of tubular frame  112  of header  20  (or threshold  26 ). If desired, depending on the desired amount of security necessary, the amount of sliding bolt  38  received inside chamber  110  can be increased or decreased. Back plate member  42  can be mounted to door  14  using a plurality of bolts, such as carriage bolts  114 , that pass through door  14  and back plate member  42 . As known to those skilled in the art, a variety of other connection mechanisms and devices are also suitable for connecting back plate member  42  to door  14 . Upper bracket  116 , currently utilized by most trailers  12 , prevents external access to sliding bolt  38 .  
     [0040] In operation with door locking component  30 , position switch  102 , keypad  46  and antenna system  44  mounted in place, the locked position (as shown in FIG. 2) has second end  38   b  of sliding bolt  38  disposed through receptor  108  inside chamber  110  of tubular frame  112  of header  20 . As such, door  14 , and consequently door  16 , cannot be opened. In order to open doors  14  and  16 , an authorized person enters the appropriate code on keypad  46  to cause controller unit  36  to operate actuator mechanism  34  to cause actuating rod  54  to move downward. Because of the connection at collar  56 , sliding bolt  38  is also moved downward such that second end  38   b  thereof is no longer engaged in or through receptor  108  into chamber  110 . Once sliding bolt  38  is free of header  20 , doors  14  and  16  may be swung open. In the preferred embodiment, integrated circuit  70  includes or is connected to a timer that will automatically operate actuator mechanism  34  after a preselected amount of time to move sliding bolt  38  upward into engagement with receptor  108  in or attached to header  20 . This feature is particularly useful if someone unlocks door lock system  10  but is called away or otherwise does not open door  14  within the preset time period. To prevent sliding bolt  38  moving upward when door  14  is open, integrated circuit  70  will only move sliding bolt  38  into locking engagement if position switch  102  indicates that door  14  is closed. If position switch  102  indicates door  14  is closed and the preset time on the timer expires, then integrated circuit  70  of controller unit  36  will send a command to actuator mechanism to move sliding mechanism into engagement with receptor  108  at or in header  20 . If door  14  is open, as indicated by position switch  102 , when the preset time on the timer expires, integrated circuit  70  will not send a command to actuate sliding bolt  38 . As soon thereafter that position switch  102  indicates to controller unit  36  that door  14  is closed, integrated circuit  70  will send the command to acuate sliding bolt  38  to engage it in receptor  108  in header  20 . In this manner, controller unit  36  will automatically engage door lock system  10  to lock door  14 , thereby eliminating the need for the driver or operator to remember to engage door lock system  10  after closing door  14 . This will eliminate unlocked doors  14  and  16  caused by human error due to forgetting to lock doors  14  and  16 . In addition to being used to automatically lock or prevent locking of door  14 , position switch  102  is utilized to report the status, open or closed, of door  14  to remote locations. When used with wireless communications, door  14  can be locked or unlocked remotely.  
     [0041] Information pertaining to the opening and closing of door  14  can be stored inside controller unit  36  and/or sent over a wireless network to the remote location, including transmissions on a real time basis. In this manner, oversight of access to the interior of trailer  12  can be maintained, thereby reducing the likelihood of unauthorized access to the contents inside trailer  12  by “insider” persons who otherwise have the codes and authority to operate keypad  46 . This should significantly reduce the likelihood of employee or related party theft of materials from trailer  12 . When used with GPS and like systems (i.e., a 911 based location system), a central command center will be able to determine if a trailer  12  is where it is supposed to be and if someone is accessing the materials stored therein. Depending on the materials being transported or stored in trailer  12 , immediate action can be taken to prevent the unauthorized removal or theft of the material.  
     [0042] The door lock system  10  of the present invention allows the person exercising control over the contents of trailer  12  to prevent anyone, including the driver, from opening door  14  by limiting access to the correct code. Keypad  46  can also be configured to receive code changes, by utilizing appropriate security level clearances, that would modify the existing code to unlock the system  10  if it were believed the security code had been compromised or if trailer  12  was being sent to a different receiving party than was originally intended (as a result, requiring a different code for the new receiving party). As discussed above, the door lock system  10  of the present invention can be configured to interact with a satellite or cellular telephone system and a GLS/GPS system such that it will transmit a signal if door  14  is opened without the proper code being entered and identify the location of trailer  12 . As also shown in FIG. 6, the door lock system  10  can work with a brake lock system  82  configured to prevent unauthorized movement of trailer  12 . When door lock system  10  is used In conjunction with brake lock system  82 , a would be thief is prevented from moving trailer  12  from its designated location, which makes theft of materials from inside trailer  12  much more difficult on the thief when he or she cannot easily open doors  14  and  16  due to door lock system  10 . As is well known, time is generally one of the primary means of discouraging a thief. If the thief is bold enough to attempt to break into trailer  12  where it sits, door lock system  10  will make this difficult and, if it happens, will transmit a signal indicating an unauthorized entry into trailer  12  to a central location or police station.  
     [0043] In addition to the safety feature regarding persons inadvertently locked inside of trailer  12 , which can be caused by accidently closing door  14  when someone inside (i.e., wind blowing, etc.), door lock system  10  is configured to prevent a broken or missing position switch  102  from causing door  14  to be stuck in a locked condition. Integrated circuit  70  is configured such that information from position switch  102  is not required to send a command to actuator mechanism  34  to disengage sliding bolt  38  from receptor  108  to open door  14 . An open command can be sent at any time from controller unit  36 . As such, if position switch  102  becomes damaged during loading or unloading materials into or from trailer  12  or if it breaks during transit, the driver, operator or other authorized person can still open door  14  by entering the correct code at keypad  46 . Naturally, if position switch  102  is damaged, door lock system  10  will not be able to be relocked, which prevents door  14  being placed in essentially a “stuck” locked condition.  
     [0044] Various modifications to the door lock system  10  are possible. For instance, instead of having second end  38   b  of sliding bolt  38  engage a hole in header  20  or threshold  26 , a separate receptor  108  can be mounted on or attached to header  20  or threshold  26 . The hole drilled into header  20  or threshold  26  is preferred because it does not interfere with the ingress and egress of materials from trailer  12  and is significantly less likely to be damaged than a separate component. If desired, depending on the environmental conditions in which trailer  12  is or will be utilized, a cover (not shown) can be placed over all or part of actuator mechanism  34  to prevent dirt, dust and other debris or fluids from contacting the covered components.  
     [0045] In another embodiment, shown in FIG. 9, instead of actuating sliding bolt  38  along a straight linear path into receptor  108 , actuator mechanism  34  is utilized to pivot tongue  118  so as to block the roll-up path of roll-up door  28 . As shown in FIG. 9, the linear movement of actuating rod  54  acts on tongue  118  so as to pivot it around pivot connector  120 . Tongue  118  is shaped and configured to pivotally react when actuating rod  54  is extended outward or drawn into main body  48  of actuator mechanism  34 . As shown, back plate member  42  is mounted to the inside wall of header  20  such that tongue  118  is pivoted from a down position that blocks the movement of roll-up door  28  to an up position along back plate  42  and header  20  that allows roll-up door  28  to be rolled along the tracks inside trailer  12 . With tongue  118  facing downward in the down position any upward movement of roll-up door  28  is prevented, thereby keeping roll-up door  28  in a closed position. The remaining components for door lock system  10  of this embodiment can be the same as described above for swing doors  14  and  16 . While there are shown and described herein certain specific alternative forms of the invention, it will be readily apparent to those skilled in the art that the invention is not so limited, but is susceptible to various modifications and rearrangements in design and materials without departing from the spirit and scope of the invention. For instance, it should be noted that the present invention is subject to modification with regard to the dimensional relationships set forth herein and modifications in assembly, materials, size, shape and use. For example, while a certain computer, electronic and radio devices and materials have been used in the embodiments of the invention set forth above, other such devices and materials could also be used. Therefore, it is contemplated that the appended claims will cover any modifications or embodiments as fall within the true scope of the invention.