WO2004073187A1

WO2004073187A1 - Security system for cargo trailers

Info

Publication number: WO2004073187A1
Application number: PCT/US2003/032458
Authority: WO
Inventors: William P. Lanigan; Peter W. Mirabella; Gerald F. Chalko; Kurt A. Moldenhauer; Maciej Labowicz
Original assignee: Mi-Jack Products, Inc.
Priority date: 2003-02-06
Filing date: 2003-10-14
Publication date: 2004-08-26
Also published as: US20060117820A1; US20040155477A1; CA2514554A1; US7059159B2; AU2003284134A1

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.

Description

SECURITY SYSTEM FOR CARGO TRAILERS

Background

This invention relates to security systems for containers having doors, and has particular application to apparatus and methods for securing roll-down and/or swing- open doors for cargo trailers.

Containers, such as cargo containers, trailers, delivery vans, storage facilities, garages, tool sheds, and cargo trailers, are often constructed with a door that is accessible from the exterior of the container. For example, sometimes a cargo container has a roll-down door. These roll-down doors often have a latching mechanism on the outside of the door that can be opened easily without a key. Other cargo containers often have a pair of swing-out doors. Such swing-out doors also have latches on the outside of the doors that can be easily opened without a key. The latches on both types of doors are often designed to be lockable using a padlock-type lock.

However, the padlocks used with either type of door can be easily defeated by thieves. For example, some padlocks can be pried open using a screwdriver or pry bar as a lever. Other padlocks can be cut by using bolt cutters or a hacksaw. In any event, an accessible padlock is often not very secure. Other security systems have been designed for one, or the other, of these two types of doors. While it may be possible to use a similar lock on both types of doors, often a lock designed for one type of door cannot be used on the other type of door. In other cases, such lock would require substantial modification to be used on the other type of door. Often, the designs of such systems are relatively bulky and they extend into the cargo area creating an unusable zone of space. An example of such security systems for either roll-down doors or swing-out doors are shown in U.S. patent no. 6,047,576. While such security systems are adequate for some uses, they are not designed to be easily interchangeable for use in both roll-down doors and swing-out doors.

A need exists for a security system that can be used for both roll-down doors and swing-out doors, such as one including a lock with a multi-directional latch. A need also exists for a security system that stores a record concerning the unlocked and/or opening of the door, such as the date, time and geographical location of such unlocked and/or such opening. Furthermore, a need exists for a lock for a container having one or more doors that allows the door to be slammed closed and locked when the lock's latch is in a locked position prior to the door being slammed closed.

Summary The disclosed apparatus and methods avoid some of the disadvantages of prior devices and methods while affording additional structural and operating advantages. In one embodiment of the invention, a method is provided for securing the cargo of a trailer having a container and cargo door accessible from the outside for closing the container and being movable from an open position to a closed position. The method comprises providing a latching device on the inside of the container. The latching device has a latch, a screw for moving the latch between an unlocked position and a locked position, and a rotary motor for turning the screw. A latch receiving device is provided, and is adapted to receive the latch, on the inside of the container. The motor may be operated to turn the screw in one direction, thereby moving the latch from the unlocked position to the locked position. The motor may be operated to turn the screw in the direction opposite of the one direction, thereby moving the latch from a locked position to the unlocked position, h one embodiment, in order to prevent back rotation, the screw has a small degree of pitch. In one embodiment, the screw has a degree of pitch no greater than five degrees and the motor has a high gear ratio to prevent back rotation of the screw.

In one embodiment of the invention, the method comprises providing a controller that controls the movement of the latch between the unlocked position to the locked position. A signal generation device is provided which is capable of sending signals to the controller. A memory is provided that is coupled to the controller. A control signal is sent, selected from a lock control signal and an unlock control signal, from the signal generation device to the controller. The unlock control signal indicates that the latch should be in the unlocked position and the lock control signal indicates that the latch should be in the locked position. In one embodiment, the method also includes storing, in memory, control data indicative of the most recent control signal sent from the signal generation device to the controller.

In one embodiment, a latch sensor is coupled to the controller. The method includes sensing, with the latch sensor, whether the latch is in the locked or unlocked position. A latch position signal is sent, indicative of whether the latch is in the locked or the unlocked position, to the controller. A door sensor coupled to the controller is provided. The method includes sensing, with the door sensor, whether the cargo door is in the open or closed position. A door position signal, indicative of whether the door is in the open or closed position, is sent to the controller. The method includes moving the latch from its unlocked position to its locked position If the signal generation device sends the lock control signal to the controller, the latch position signal indicates that the latch is in the unlocked position, and the door position indicates that the door is in the closed position.

In one embodiment, a memory is coupled to the controller, with the memory being capable of storing control data indicative of the most recent control signal sent from the signal generation device to the controller. In one embodiment, the latch has an end receivable by the latch receiving device, with the latch including a plurality of locked flanges adjacent the end with at least two locked flanges projecting out in different directions. A more detailed explanation of the invention is provided in the following description and claims, and is illustrated in the accompanying drawings.

Brief Description of the Drawings For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.

FIG. 1 is a fragmentary, front view of the inside view of closed swing out doors of a cargo container with the locked device in the locked position; FIG. 2 is a fragmentary, internal right-side view of a cargo container having a security system with the locked device in the locked position;

FIG. 3 is an internal top view, with the header removed for clarity, of the interior view of the swing out type door for the cargo container of FIG. 1;

FIG. 4 is an enlarged sectional view taken along the line A-A in FIG. 2; FIG. 5 is an enlarged sectional view taken along the line B-B in FIG. 1 ;

FIG. 5a is side view in partial section similar to FIG. 2;

FIG. 5b is a view similar to FIG 5a having a break-in force applied to the door; FIG. 5 c is a view similar to 5b showing the movement of the door when a large break-in force is applied;

FIG. 6 is a view similar to FIG. 5, with the door partially open and the locked

device in a locked position;

FIG. 7 is a view similar to FIG. 5, with the locked device is in the unlocked

position;

FIG. 8 is a view similar to FIG. 6, with the latch engaging the latch receiving device;

FIG. 9 is a view similar to FIG. 8 ,with the bolt engaging along the bottom portion of the latch receiving device; FIG. 10 is a partial, cut-away, front view of the internal portion of a roll up door with a locked device on a cargo container with the locked device in the locked position;

FIG. 11 is a top view of the cargo container of FIG. 10;

FIG. 12 is a side view, with a portion of the door frame removed for clarity, of the cargo container of FIG. 10;

FIG. 13 is a partial sectional view taken along lines A- A of the cargo container of FIG. 11 , with the door in a partially open position and the latch in the unlocked position; FIG. 14 is a view similar to FIG. 13, with the door in a partially open position and the latch in the locked position;

FIG. 15 is a view similar to FIG. 13, with the latch engaging the latch receiving device as the door is pulled down toward the closed position; FIG. 16 is a view similar to FIG. 13, with the door pulled closed and the latch in the locked position;

FIG. 17 is a schematic diagram of an electronic Control Unit that can be used with the disclosed devices;

FIG. 17a is a schematic diagram showing subcomponents of one form of the

electronic Control Unit of FIG. 17;

FIG. 18 is a flow chart for one example of a program that is run by the ECU of FIG. 17; and

FIGS. 19-31 is a flow chart for one example of a program for configuring the lock, providing report information, and creating a maintenance reminder schedule. Detailed Description

Turning now to the drawings, and, more particularly, FIG. 1 thereof, there is depicted a portion of a cargo transporter vehicle 10, such as a truck, train, ship, or airplane. Cargo transport vehicle 10 includes a container having doors, such as cargo trailer 12 (shown in partial section), having doors 14 and 16. In one form, doors 14 and 16 are of the swing-out variety. Similar swing-out doors are shown in U.S. patent nos. 6,047,576; 5,931,033; and 5,806,355. Cargo trailer 12 typically includes a header 18, which acts as a frame that provides strength and rigidity to the cargo trailer 12. A locked device 20 is provided in cargo trailer 12 and can include latch receiving device 22. In one form, latch receiving device 22 is bolted or otherwise attached to the underside 19 of container header 18. Latch receiving device 22 can be is located very near to, or right against, door 14 when door 14 is in the closed position, as shown in FIG. 2. Latch receiving device 22 is compact to minimize the amount of space it extends away from the closed door in order to minimize the unusable zone of space in cargo trailer 12. In one form, latch receiving device 22 extends less than 5 inches from closed door 14 or can extend less than 4 inches, 3 inches or even 2 inches from the closed door 14. Good results have been achieved when latch receiving device 22 extends about 2-7/8 inches and even as little as about

1-1/2 inches from closed door 14.

As shown in FIG. 2, latch receiving device 22 can include a downwardly and rearwardly projecting portion 24 that projects downward from header 18 and inward from door 14. This angled portion minimizes damage to cargo if it were to hit latch receiving device 22 as it is loaded into cargo trailer 12. Additionally, latch receiving device 22 is less likely to be knocked off header 18 if it is hit as cargo is loaded into the trailer. A rearwardly projecting lip 26 is coupled to downwardly and rearwardly projecting portion 24 and projects inward from door 14. In one form, rearwardly projecting lip 26 is approximately parallel to the underside 19 of header 18. In a preferred form, the distance that latch receiving device 22 projects downward from header 18 is minimized in order to minimize the unusable zone of space in cargo trailer 12. In one form, latch receiving device 22 can project less than 5 inches, or less than 4 inches, less than 3 inches, less than 2 inches, and even about 1-3/16 inches downward from header 18 when latch receiving device 22 is mounted to header 18. Locked device 20 includes latching device 28 having a latch 30. Latch 30 can be supported by housing 32. Latch 30 is rigidly attached to door 14, such as by bolting housing 32 to bracket 34 using bolts 35. Similarly, bolting bracket 34 can be attached to door 14 with bolts and nuts 37. Although bolts 35 and 36 are shown, any other appropriate fastener can be used to couple latch 30 to door 14, including screws, welds, adhesives or an appropriate tongue and groove system coupling door 14 and latch 30. However, if bracket 34 is removably coupled to housing 32 (such as with bolts and nuts, screws, or a tongue and groove system), a user can mount brackets to doors on different containers and keep a relatively small inventory of locked devices 20 to be used, as needed, on different containers.

In one form, an angled deflector cover 38 (shown as dashed lines in FIG. 3) can be bolted to door 14 or can be an integral part of housing 32. Housing 32 can include a subhousing, such as motor housing 40, coupled to it. Angled deflector cover 38 covers latching device 28 to protect it from being damaged from shifting cargo or from being struck during the loading or unloading process. For example, the angled deflector cover 38 can help protect latching device 28 when the swing-out doors are open and swung back along the sidewalls of the container, thus exposing angled deflector cover 38 and latching device 28 to the exterior of the container. If a truck were to hit the exposed angled deflector cover 38 (now along the exterior sidewalls of the container) the angled deflector cover will protect the latching device

28 and cause the open doors to flex as the truck moves past.

Referring to Figs. 4-9, housing 32 and latch 30 cooperate to allow latch 30 to extend and retract from housing 32. In one form, tabs 42 of housing 32 protrude within indentations 44 of latch 30, thereby allowing latch 30 to ride within housing 32 and also limit the amount of travel of latch 30. Such limits on the travel of latch 30 prevents latch 30 from extending too far into housing 32 or too far out of housing 32. This also prevents latch 30 from falling out of housing 32. Additionally, as shown in FIG. 4a, the limit on travel of latch 30 can be used to provide a drive line isolation gap 33 that isolates latch 30 from drive nut 52. Drive line isolation gap 33 allows latch 30 to move a certain amount without contacting drive nut 52 and, thereby, without causing a strain on drive screw 48 that would be transmitted to coupling 50 and motor 47. In other words, drive line isolation gap 33 is one way to isolate motor 47 from the forces that are acting on latch 30 when an attempted break-in occurs or as the doors move during transport or when parked on an uneven surface. The creation of drive line isolation gap 33 is explained below.

Replaceable wear pads 46 can be provided to prevent latch 30 and housing 32 from wearing against one another. Replaceable wear pads 46 can be made from any suitable material that preferably has a low coefficient of friction and is resistant to wear. In one form, wear pads 46 can be made from an oil impregnated nylon, or other plastic, such as that sold under the trademark Nyloil. Replaceable wear pads 46 also prevent corrosion or rust from locked latch 30 and housing '32 together. Replaceable wear pads 46 also prevent interaction between latch 30 and housing 32 that can create problems, especially if dissimilar metals or other materials are used. A drive, such as a 12v bidirectional DC gear motor 47, is provided and coupled to a drive screw, through coupling 50, for driving latch 30 into an extended or retracted position. In one form, drive screw 48 has a small degree of pitch, such as 5° or less. This small degree of pitch aids in preventing backdrive due to vibration that can be caused, for example, by movement of a cargo trailer or when someone is trying to break into the doors.

Additionally, motor 47 is more efficient than the solenoid used in other devices. Such solenoids often use 5 to 10 amps to move the latch, whereas the gear motor typically uses less than 5 amps, and may use less than 1 amp of power to move latch 30 to either the locked position or the unlocked position. In one form, gear motor 47 uses less than 200 milliamps to move the latch to either the locked position or unlocked position. Additionally, motor 47 does not require power to keep latch 30 in the locked position, whereas prior solenoid driven devices ordinarily needed to

maintain the solenoid energized to keep the latch in place. Other prior solenoid devices attempted to overcome this excess energy usage by using mechanized means to keep the solenoid in place; however such systems required additional power to overcome the mechanized means when the latch was moved.

Drive nut 52 is threaded on drive screw 48. Alternatively, a portion of latch 30 can be threaded appropriately so it mates with drive screw 48 in order to take the place of drive nut 52. A spring, such as coil spring 54, is coupled between drive nut 52 and latch 30. In one form, a hollow portion of latch 30 carries coil spring 54, such that one end of coil spring 54 rests against drive nut 52 and the opposite end presses against a portion of latch 30. This causes a force to be exerted between the threads of drive nut 52 and drive screw 48, thereby increasing the frictional force between them.

This also aids in preventing any backdrive, of the drive nut 52 and drive screw 48, due to vibration. Also, the use of spring 54 acts in conjunction with drive nut 52 (which is not secured to latch 30) and drive line isolation gap 33 to isolate forces that are exerted on latch 30, such as those that occur during an attempted break-in, from being transmitted to drive screw 48 and thus to coupling 50 and motor 47. In other words, spring 54 is a second way to isolate motor 47 from the forces that are acting on latch 30.

In one form, latch 30 is a universal latch or a bidirectional latch that can be used to lock the door without the latch having to face in only one of a multiple of possible directions. In other words, the latch works when facing one of at least two different directions. In another form, latch 30 could be a universal latch that can be rotated in housing 32 to face an appropriate direction for to allow the same locked system to be used on different types of doors. In either case, the universal latch allows the latching device to be used in more than one orientation.

For example, as shown in FIGS. 4 and 5, latch 30 includes locked flanges 56 and 57 that extend outward from the body of latch 30 at approximately a 90° angle. Flanges 56 and 57 also extend outward from latch 30 in directions that are approximately 90° from one another. These locked flanges 56 and 57 can act to capture latch receiving device 22 to prevent latch 30 from moving past latch receiving device 22 when the doors move, such as when they rack while in transit or when parked over uneven terrain. The racking of the doors causes the gap between the door and the header to increase or decrease by roughly 3/4 inch. When the doors rack and the gap between the door and header increases a certain amount, locked flanges 56 or 57 contact lip 26 and prevent latch 30 from passing under latch receiving device 22.

In one form, locked flanges 56 and 57 mirror or are at a complementary angle to lip 26 to aid in preventing latch 30 from passing under latch receiving device 22.

Latch 30 can include one or more latch engaging surfaces 58 and 59. In one form, latching engaging surfaces 58 and 59 are at a complementary angle to downwardly and rearwardly projecting portion 24 of latch receiving device 22. Latch 30 can also include a small cut-out portion 60 and 61 beneath latch engaging surfaces 58 and 59. Cut-out portions 60 and 61 can be angled slightly, such that cut-out portions 60 and 61 are shallower at a portion nearer locked flanges 56 and 57 compared to a portion that is further from locked flanges 56 and 57. Although cut-out portions 60 and 61 are referred to as being cut out, they can be formed in any appropriate manner and do not required that material specifically be removed. Similarly, cut-out portions 60 and 61 could have a curve as its profile, instead of the straight angled line shown in FIGS. 4 and 5. The combination of locked flange 56 (or 57) and cut out portions 60 (or 61) allows for increased flexibility of installation and a more robust design. The spring 54 and the latch 30 also allow for increased flexibility of installation and a more robust design because spring 54 can compress and allow latch 30 to move when contacted by header 18, or another part of cargo trailer 12, when the doors rack and the gap between the door and the header decreases.

One or more sensors, such as optical sensors or mechanical reed switches 64 and 65 (FIG. 13) can be provided in housing 32 to sense when latch 30 has moved to a locked or unlocked position. In one form, an actuator 66 is coupled to latch 30 and moves so that it comes in contact with reed switches 64 and 65 so that the movement of actuator 66, and the latch 30, can be sensed. Alternatively, reed switches 64 and 65 could sense the movement of a particular portion of latch 30. In one form, a single sensor could be used to sense when latch 30 is in one of the locked and unlocked positions. If it is not in the one position, then it could be assumed that latch 30 is in the other position. When in use on a swing-out type door, such as doors 14 and 16, latch receiving device 22 is attached to the header or another portion of the ceiling of the cargo transport vehicle 10. Alternatively, a portion of header 18 can be cut out with the remainder replacing the latch. In other words, latch 30 would extend into the opening in header 18 to be in the locked position and clear the opening in the unlocked position.

Latching device 28 is secured to one of doors 14 and 16 such that latch 30 travels in a direction with a large vertical component, such as the vertical direction. FIG. 6 shows door 14 open and the latch 30 in the extended or locked position. As door 14 is closed, latch engaging surface 59 contacts downwardly and rearwardly projecting portion 24 (see FIG. 8), such that as the door closes, latch 30 ramps down portion 24, thereby moving downward and compressing spring 54. This allows latch 30 to clear the bottom of rearwardly projecting lip 26. When door 14 is fully closed, as shown in FIG. 5, latch 30 clears the end of rearwardly projecting lip 26 and spring 54 forces latch 30 back to the locked position.

If an opening (not shown) is made in the header (as previously suggested) to use as a latch receiving device, then the bottom corner 21 of header 18 is the latch engaging device that contacts downwardly and rearwardly projecting portion 24, such that as the door closes, latch 30 ramps down corner 21, thereby moving downward and compressing spring 54. As previously mentioned, latch 30 would then extend into the opening in the header when the door is fully closed.

In one form, cut-out portion 61 is angled to provide an engaging slope which counters the door flex experienced during a break-in. This angle provides less clearance between latch receiving device 22 and latch receiving portion 22 for a portion that is nearer locked flange 57. As seen in FIGS. 5a-5a, as force 11 is applied to the bottom of door 14, the bottom of door 14 moves outward (in the direction of an open position) cut-out portion 61 contacts lip 26 (see FIG. 5b). As bottom 14 moves further outward, the angle of door 14 changes with respect to header 18 and the cut- out portion 61 moves such that it comes closer to parallel with the face of lip 26 that it contacts. In other words, cut-out portion 61 is angled away from the direction of movement of the door during an attempted break-in, such that cut-out portion 61 is in a relatively vertical plane when door 14 has flexed a normal amount during a break-in attempt. To unlock the device, motor 47 drives coupling 50 and drive screw 48, thus causing drive nut 52 to run down the length of drive screw 48. As shown in FIG. 1, since latch 30 is secured to drive screw 48, latch 30 follows drive screw 48 downward and retracts within housing 32 until it clears latch receiving device 22 and is in the unlocked position. Reed switches 64 and 65 are used to determine when latch 30 is in the unlocked position and power can be cut to motor 47.

In order to move latch 30 to the locked position, drive motor 47 and drive screw 48 reverse direction and cause drive nut 52 and latch 30 to travel upward so that latch 30 extends from housing 32 until it is in the locked position, as shown in FIGS. 5 and 6 and indicate when power should be cut to motor 47. In one form, when reed switches 64 and 65 sense that latch 30 is in the locked position approximately when tabs 42 and indentations 44 prevent latch 30 from traveling any farther out of housing 32. Motor can continue running for a short period after tabs 42 and indentations 44 prevent latch 30 from traveling any farther out of housing 32 in order to move drive nut 52 slightly further along drive screw 48, thereby creating gap 33 between drive nut 52 and latch 30. As described above, gap 33 helps prevent forces that are acting on latch 30 from being transmitted to motor 47 and coupling 50.

The term "locked position" denotes any position where latch 30 will prevent the door from opening if latch receiving device 22 was between the door and latch 30, such as shown in FIG. 5. In other words, door 14 does not have to be closed when latch 30 is in the "locked position." Likewise, the "unlocked position" refers to latch 30 being retracted such that it will clear latch receiving device 22 when the doors moved from the closed to the open position.

Referring now to FIGS. 10-16, there is shown the locked device 20 in use with a cargo transport vehicle 10 having a roll-down type door 15. Roll-down type door 15 rolls up to open and down to close. Latch receiving device 22 is mounted to roll- down door 15 such that what was downwardly and inwardly projecting portion is now upwardly and rearwardly (towards the interior) projecting portion 25 and rearwardly projecting lip is now upwardly projecting lip 27. Latching device 28 is mounted to side wall 17 so that latch 30 retracts and extends in approximately a horizontal direction with respect to the floor of cargo trailer 12.

The operation of locked device 20 is similar to what was previously described, with some minor exceptions. Referring to FIGS. 14-16, there is shown the operation of roll-down door 15 being pulled down to the closed position with latch 30 extended or in the locked position. As roll-down door 15 moves downward, latch engaging surface contacts and engages upwardly and rearwardly projecting portion 25 and slides along such portion and causes latch 30 to be pushed within housing 32. This causes spring 54 to be compressed, as shown in FIG. 15. After latch 30 has cleared latch receiving device 22, the compressed spring 54 exerts a force on latch 30, extending it out of the housing and into the locked position. Here, it is locked flange 56 that prevents latch receiving device 22 and door roll-down 15 from being moved upward past latch 30 when latch 30 is in the locked position. Otherwise, the operation of the motor and movement of latch 30, from the retracted or unlocked to the extended or locked position, is largely the same. However, latch 30 is moved in a direction that has a large horizontal component, as opposed to a large vertical component, because of the orientation of locked device 20.

In one form, spring 54 is precompressed so that is exerts a biasing force against drive nut 52 so that the threads of drive screw 48 and drive nut 52 are forced against one another, which helps prevent drive nut 52 from moving down drive screw

48 due to vibration, such as when traveling. When latch receiving device 22 is used with the swing-out doors, it is preferably placed very close to the door or right against the door and the lock mechanism is very close to the door to prevent talcing up excess cargo space. In one form, locked device 20 protrudes less than 4 inches from the door (on swing out type doors) or trailer sidewall (on roll-up/roll-down type doors), and can be less than 3 inches and even as small as 2.6 inches (including bracket 34). In one form, locked device 20 is less than 3 inches and can be less than 2 inches and even less than 1.6 inches, such as 1.56 inches (if bracket 34 is omitted and locked device 20 is attached directly to the trailer sidewall or door). Similarly, latch receiving device 22 is also a low profile device and can extend no more than as little as 1-7/8 inches from the roof or header (on swing-out type doors) or door (on roll- up/roll-down type doors).

As shown in FIGS. 1, 2 and 4-9, latch receiving device 22 can be located on header 18 right up against the door when the door is in the closed position. Because of the motor and screw drive, the placement of locked device 20 is more robust since the screw allows for a flexible stroke configuration, thereby allowing less exact placement of locked device 20. Motor 47 and the drive system can be a linear system and a direct drive system that does not use gears between motor 47 and latch 30. The linear system enables improved optimum power transfer. Coupling 50 is a flexible coupling between the motor and the screw and reduces vibration from being passed to the motor from latch 30. It should also be noted that if latch receiving device 22 were not used on the swing-open type door and instead was replaced with an opening in header 18, latch engaging surface 59 would engage the corner of the header adapter and still force latch 30 downward as the door is closing. In one form, motor 47 can have a high gear ratio, such as 15, 20, 25, 30, 40 or 50 to 1 to make it more difficult for the drive screw 48 to turn, due to vibrations during movement of cargo trailer 12 or otherwise, and cause latch 30 to move to the unlocked position. In one form, the gear ratio is 43 : 1. The gear ratio is important because it allows the lock to open relatively quickly, makes a more efficient use of power. Additionally, it is preferred if the gear ratio is high enough to break ice that may form between latch 30 and latch receiving device 22.

It should be noted that the disclosed locked device has three levels of security for the locked device. First, the locked device is extended so that it interferes with latch receiving device 22. Second, either locked flange 56 or 57 prevents latch 30 from moving past latch receiving device 22 as the cargo doors shifts, such as when parked on an angle while traveling down the road, or during an attempt to break into the cargo trailer. Third, tabs 42 and indentations 44 prevent latch 30 from being pulled completely out of housing 32. In one form, the diameter of drive screw 48 is selected with respect to the pitch to allow faster travel. The greater of the diameter for the same pitch, the faster the screw travels with the same rpm. For example, the diameter of the screw is less than % of an inch and can be less than Y_ inch, less than 3/8 of an inch, less than ^lA of an inch and can even be 1/8 of an inch or less in thickness. Additionally, the drive screw 48 allows for a more robust design and requires less tolerances for attaching latching device 28 on the door. This is because motor 47 can be controlled to rotate drive screw 48 by different number of rotations to adjust how much latch 30 extends out of housing 32. Latch 30 and housing 32 can contain holes for weight reduction and/or to provide drainage. In one form, an o-ring seal is provided between housing

32 and latch 30.

Although locked device 20 is shown mounted to a door and header for the swing-out doors, it could be mounted across both doors such that latch receiving device 22 is mounted on one door, latching device 28 is mounted on the other door and latch 30 moves in approximately horizontal direction to move between an unlocked position and a locked position. Alternatively, latching device 28 can be mounted on the door near the floor (in either a swing-out or roll-up/roll-down type doors) and an opening can be made in the floor to be used as a latch receiving device. Because of the loads placed on a door during attempted break-ins, a steel door can have the locked device installed at the top without much of a problem, whereas a semi-thick door might be have the lock placed at the middle of the door height and a thin door might have the locked device installed near the bottom of the door. However, due to possible load shifts, it is preferred to mount the lock at the top or bottom because it might bind at the center. In one form, locked device 20 includes a controller, such as electronic control unit (ECU) 100 (FIGS. 17 and 17a). ECU 100 allows locked device 20 to go from a stand-alone lock to a device that can be coupled with telematic (gps, cellular, gls, wireless networks, etc) or rf systems to provide a security system that logs various events. ECU 100 can be supported by housing 32, such as by being mounted inside housing 32 near motor 47 or mounted within motor housing 40. ECU 100 can be comprised of microcontroller 190 that may include a memory (not shown) or that has a memory coupled to it. A real time clock 191 can be coupled to allow the timing of various events to be recorded in a event memory 192 coupled to microcontroller 190. Such events can include opening or closing the door, the latch moving to either an unlocked condition or a locked condition, an attempted break-in, problems or errors in the execution of commands or in the status sensed after a command (discussed later). In one form, event memory 192 can record the time, location, and individual (or keyfob) associated with a particular event. Event memory 192 can be designed to make it difficult to erase and can be set up to override older information with newer information. Real time clock 191 can have an independent battery, that can preferably last from one month to ten years, in order to provide the time of events stored in event memory 192.

A power management device, or program, 193 can be provided to adjust the operation according to the type of power used and to allow the power input to be switched between several different power supplies, such as the truck, stand alone battery coupled to locked device 20, solar panels, etc. In one form, the power management device 193 is used to automatically recharge the stand alone battery, whenever it is feasible, and senses the power left in the stand alone battery before the latch 30 is moved to the locked position in order to determine whether enough power is likely to be left afterwards to move the latch back to the unlocked position. If there is not enough power, power management device 193 can be programmed to trigger a visual or audible warning and either not move latch 30 to the locked position, or require the user to confirm that they want latch 30 moved to the locked position even though there may not be enough power left to move it back to the unlocked position. The locked device 20 can be configured to run on a variety of voltages, such as 12 vdc or 24 vdc. The power management device 30 can be used to sense or control and of the above described options associated with power management. ECU 100 is electrically coupled to motor 47 and controls the operation of motor 47. As shown in FIG. 1, motor 47 can include a plurality of leads 70, 71 and 72 for providing electrical power to the motor. For example, lead 71 can be comiected to ground, whereas lead 70 provides power to motor 47 to cause the motor shaft to rotate in the clockwise direction and lead 72 provides power to motor 47 to cause the motor shaft to rotate in the counterclockwise direction. Alternatively, a two lead version can be used where switching the polarity of the voltage changes the direction of rotation of motor 17.

ECU 100 includes outputs, such as two dedicated dry-contact outputs 102, for controlling the power provided to motor 47. In one form, ECU 100 sends a signal through one of dedicated dry-contact outputs 102 to cause power to be applied to lead

70, thereby rotating the shaft of motor 47 in the clockwise direction and extending latch 30 into the locked position. Similarly, ECU 100 can send a signal through the other output 102 to cause the shaft of motor 47 to rotate in the counterclockwise direction, thereby retracting latch 30 into the unlocked position. In one form, the previously mentioned signals activate a switch (or switches) to supply power to the appropriate lead 70 or 72.

ECU 100 can also include one or more inputs, such as two dedicated dry- contact inputs 104, that are coupled to sensors 64 and 65. For example, as latch 30 extends out of housing 32 into the locked position, actuator 66 passes and is sensed by optical sensor 64, which sends a signal to one of inputs 104 to indicate that latch 30 is in the locked position. Similarly, when latch 30 retracts back into housing 32 and moves to the unlocked position, actuator 66 passes near and is sensed optical sensor 65, which sends a signal to the other of inputs 104 to indicate that latch 30 is in the unlocked position.

A receiver, such as RF receiver 106 is electrically coupled to ECU 100. A transmitter, such as an RF two channel key-fob transmitter 108, can be provided with two RF outputs to transmit signals to RF receiver 106. The signals transmitted from RF transmitter 108 are command signals that are used to control ECU 100 to control other things. For example, one RF output signal of transmitter 108 can be used to cause ECU 100 to activate motor 47 and move latch 30 to the locked position. The other of the RF outputs of RF transmitter 108 can cause ECU 100 to activate motor 47 and move latch 30 to the unlocked position.

Alternatively, a RF three channel (or any other suitable number of channel) key-fob transmitter can be used. Multiple key-fob transmitters 108 can be provided and each might be separately coded so that the identity of the particular key-fob 108, and thus the individual entrusted with that key-fob, can be recorded in event memory 192 with any other appropriate information regarding the particular event. If a three channel fob is used, the third channel can be used to indicate an alarm condition or can be used as a master fob to enable, or disable, the ECU from responding to a signal from other fobs. In one form, the fobs are programmable in the filed using a laptop. ECU 100 can be provided with a plurality of other inputs or outputs 110. For example, three dedicated dry-contact inputs could be used to hardwire a key operated switch (like those found on some elevators) and a door open sensor. Two of inputs

110 can be used with the key operated switch, one for transmitting a lock command and the other for transmitting an unlock command. The third contact could be used with a sensor (similar to the mechanical sensor switch that turns on a refrigerator light) that produces a signal when the door is open. In one form, such sensor can take the form of a magnetic switch (see 75 in FIGS. 1 and 15) that sends a signal when the door is opened and, thus, moves away from the magnetic switch. In one form, the magnetic switch is a magnetic reed switch. Additional spare dry-contact inputs can be provided for additional external switches or sensors for connection to the door or other devices to cause the door to be locked or unlocked or to provide for input from other appropriate devices.

Input outputs 110 can also include a plurality of dedicated dry-contact outputs for feedback signals sent to other devices. Such signals can include that the latch is locked, unlocked, the door is closed or opened, or an error signal. In one form, an error signal is generated if two different sensors indicate opposite states, such as one sensor indicating that the latch 30 is locked and the other sensor indicating that latch

30 is unlocked.

In one form, a signal is sent to a device, such as a camera, to activate thp device when the vehicle door is opened. When a camera is used, a record can be made of any loading and unloading activities when the door is opened. One, or more, feedback signals can be used to activate a siren or other warning device. In one form, a warning device is located in the cab and indicates that the door is unlocked or that the door is opened. In selected situations, an output signal can be used to lock the front of a cab hauling the cargo trailer 12 or to disable the cab. Other contacts can be provided to connect to an appropriate power source, such as a DC power source used for cargo transport vehicle 10. However, housing 32 could carry its own power source.

A plurality of serial ports 112, 113, such as a nine-pin connector communication port that is often referred to as RS 232, can be provided to interface with one or more auxiliary devices, such as a programming terminal or computer, a keypad, a telemetric device, a GPS tracking device, a serial sensing device, or a modem. Such auxiliary devices can be used to send signals to ECU 100 to lock or unlock latch 30. They can also be used to program ECU 100 or to download information stored in ECU 100's memory or other memory associated with ECU 100. In one form, a keypad is provided that requires the entry of an employee identifying code to unlock the door so that a record of the unlocked of the door can be saved in memory. The telemetric device and GPS tracking device, can be used to track the location of the cargo transport vehicle 10 when the cargo door is opened and locked and send the data to a remote location. In one form, ECU 100 is normally in the sleep mode and "awakens" when a command is sent or a signal is sent from one of the sensors or other devices.

FIG. 18 shows a simplified example of a program that is run by ECU 100. Power is supplied to a locked device 20 at 120 from an appropriate power source, such as a rechargeable or replaceable power source that is part of locked device 20 or that is mounted separately. Alternatively, or in addition, power can be provided from the cargo transport vehicle 10 that is transporting cargo trailer 12. However, any other appropriate source of power can be used. The program starts at 122 when a lock mode request 124 or unlock mode request 126 is supplied to ECU 100. In one form, the lock request comes from RF transmitter 108.

If the lock mode is requested, the program determines whether the door is closed at 128. If the door is not closed, then the program ends and goes back to start 122. However, if the door is closed at 128, a determination is made as to whether or not the latch is already locked at 130. If the latch is locked the program ends and goes back to start 122. If the latch is not locked, a lock command is generated at 132. The lock command is used to energize motor 47 at 134 to cause motor 47 to move latch 30 to the locked position. There can be a delay 136 and then a determination is made as to whether or not latch 30 is in the locked position at 138. If latch 30 is in the locked position, a latch lock signal is generated at 140 and may be provided to a desired output device, such as a buzzer, an indicator light, an LED output or an LCD screen, and the program ends. If the latch is not locked at 138, then an automatic retry command can be generated at 142 to cycle the program back to generate lock command 132. If the latch is still not locked after the retry command 142, or after a second or other number of retry commands 142, then an error signal is generated at 144 and provided to an appropriate auxiliary device, such as a buzzer, an indicator light, an LED output or an LCD screen.

In one form, the system can be programmed to have an automatic locked feature 146. The automatic locked feature 146 automatically moves the latch to the locked position a predetermined time after the door is closed. If the automatic locked feature 146 is selected an internal check 14 is made to determine if the latch is in the process of trying to lock or unlock. If it is in the middle of locked or unlocked, the automated locked feature 148 will wait until the locked or unlocked function is completed. If the latch is idle, the door is sensed as being closed at 148 and the latch 30 is in the unlocked position, then there is a delay 150 and then the program enters the lock mode request side to generate a lock command at 132 to automatically lock the door after the delay 150. In one form, the delay period used in the software is selectable by the user and may be, for example, 90 seconds. Such a feature is designed to automatically lock the door within a predetermined time after the door is moved to the closed position.

If the unlock mode request 126 is made, it is first determined whether latch 30 is in the locked position at 152. If latch 30 is not locked, the program ends and goes back to start 122. If latch 30 is locked, an unlock command is generated at 154 and motor 47 is energized at 156. This causes the motor shaft to rotate in the appropriate direction to retract latch 30 and move it to the unlocked position. After a delay 158, it is determined whether the latch is unlocked at 160. If the latch is unlocked, a latch unlock signal can be generated at 162 and sent to an appropriate auxiliary device, such as an LCD screen. Additionally, an audio signal, such as a chirp can be generated to indicate that the latch is being unlocked. If the latch is not locked, the program can go back to the generate an unlock command at 154 by having one, or more, shot retry command 164. If latch 30 is still not unlocked after going through the retry command 164 (or after a specific number of times going through the retry commands), then a latch unlock error signal can be generated at 166 and displayed on an appropriate device, such as a buzzer, an indicator light, an LED output or, an LCD^' screen.

In one form, an automatic relocked feature 168 can be provided to be selectable by the user. The automatic relocked feature automatically relocks the door a predetermined time after the door is unlocked if the door has not yet been opened.

If the auto relock option 168 is selected and the latch is unlocked at 160, the system determines if the latch is in the process of being locked or unlocked. If it is not in either process, the system determines if the door is closed at 170. If the door is not closed, it loops around to 168 to check if the door is closed at 170 again. If the door is closed, a delay 172 occurs and then the program returns to the lock mode request,

such as at 130. >

In one form, each time latch- 30 is unlocked, a short delay occurs to allow the door to be opened and then ECU 100 automatically relocks latch 30. This prevents a user from unlocked the door and then leaving it unlocked and unguarded, such as while deciding to take a coffee break. Each of the delays, discussed above, can be user adjustable to allow an appropriate time period for the delay according to the particular circumstances and security required by the user.

It should be noted that the auto relock and/or auto lock feature can cause latch 30 to move to the locked position even when the door is in the open position. Even if latch 30 is locked and the door is open, the door can be closed and locked because the user can slam the door shut and latch 30 will move downward compressing spring 54 until it has cleared latch receiving device 22. As previously mentioned, compressed spring 54 will cause latch 30 to move back to the locked position. FIGS. 19-31 show a more complex program 200 that can be run by ECU 100. In one form, many different options are available to be configured. For example, the various input or output ports can be enabled, disabled, or otherwise configured at FIGS. 20 and 21. Input/output ports can be configured for a variety of baud rates, data bits, parity, stop bits, or flow control at FIG. 21. The automatic locked and automatic relocked features can be enabled or disabled at FIG. 22. Narious alarms, or other warning devices, including low battery, locked, unlocked, a combination locked and unlocked, unauthorized entry, door open and closed, or cycle counter alarms can be enabled or disabled at FIGS. 23 and 24. In one form, such alarms can be sensed locally, such as through the use of audible alarms (see FIG. 24) or visual alarms.

Data concerning each alarm, or other event, can be stored locally in memory and may include the date, time, geographical location and a key-fob or individual associated with the alarm or event. In one form, one or more of the alarm signals can be transmitted to a remote location, via a cellular phone or telemetric device connected to ECU 100, or other suitable method. A record of such alarms could be transmitted to a remote computer system or the internet for keeping track of a plurality of vehicles at the same time and storing similar data concerning such alarms or other events. In one form, a GPS device can be used so that alarms and data can be transmitted (and/or recorded locally) with the time and location of each occurrence. For example, if no unlock command is received and the door is sensed as open, data signifying the event (such as date, time, location and type of event) can be recorded locally and/or transmitted to a remote location and an alarm can occur locally and/or remotely. The amount of time for one, or more, delays can be selected at FIG. 25 and the type of data stored in memory, or transmitted to another location, can be selected at FIGS. 26 and 27. One, or multiple, cycle counters can be configured to count the number of times that the door is locked, unlocked, or opened at FIG. 28. Additionally, a cycle counter may keep track of the amount of time since the last time locked device 20 was serviced. The cycle counters and cycle counter alarms can be used to note when locked device 20, or a portion thereof, should be serviced.

The use of vehicle power or standalone power can also be enabled or disabled at FIG. 28. If the used of standalone power is enabled, a sleep mode can be used to conserve energy. In this case, a wake up period can be selected (at FIG. 28) so that the system wakes up periodically and checks the various sensors to see what status everything is in, or checks the input/output status, and compares the status with the status that is stored in memory. If necessary, the system signals the appropriate alarms, and transmits any appropriate alarms or other signals. For example, if the stored data indicates the latch should be locked, but the sensor indicates that the latch is in the unlocked position, the processor can automatically activate the motor to cause the latch to move back to the locked position. If a signal command is made while the system is in sleep mode, the system will disregard the timer and wake up to execute the appropriate command. The timer can then be reset and the system can return to idle mode. Other options are shown in FIGS. 29-31, which are evident from the figures.

Some, or all, of the above options might be user configurable and reconfigurable by the user. For example, the configuration of the software can be updated, or the preferences changed, in the field by connecting a laptop (or other appropriate device) to an input of the ECU. Some, or all, of the options might be pre- configured by the manufacturer or reseller to allow the same device to be sold at different price points dependant on the options desired by the user.

Additionally, a memory can be provided to keep a running record of the locked and unlocked commands and/or other operations along with other signals sent or received by ECU 100. In one form, such memory is coupled to ECU 100 and the record can be downloaded to another device, such as a portable computer, via one of the input/output contacts of ECU 100. Additionally, the program can cause an indication that maintenance is needed, such as by using a service light or indicating service is required on a screen. Such screen can be located on a device having a keypad, such as a nine key device. Examples of service required could be replacement of wear pads or other parts, cleaning and/or greasing latching device 28, or replacing the coil spring.

The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants' contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.

Claims

What is claimed is:

1. A method for securing the cargo of a trailer having a container and cargo door accessible from the outside for closing the container and being movable from an open position to a closed position, the method comprising: providing a latching device on the inside of the container, the latching device having a latch, a screw for moving the latch between an unlocked position and a locked position, and a rotary motor for turning the screw; providing a latch receiving device, adapted to receive the latch, on the inside of the container; operating the motor to turn the screw in one direction and thereby moving the latch from the unlocked position to the locked position; and operating the motor to turn the screw in the direction opposite of said one direction and thereby moving the latch from the locked position to the unlocked position.

2. A method as defined in claim 1 , in which providing the latching device includes fastening the latching device to the inside of the cargo door, wherein providing the latch receiving device comprises fastening the latch receiving device on a portion of the container.

3. A method as defined in claim 1 , including providing a switch that operates said rotary motor and wherein operating said motor comprises the step of actuating said switch.

4. A method as defined in claim 3, wherein said switch is actuated from the outside of said trailer.

5. A method as defined in claim 1, further comprising: providing a spring coupled between said screw and said latch; moving the cargo door is moved from the open position, with the latch in the locked position, toward the closed position; contacting the latch receiving device with the latch and thereby moving the latch toward the unlocked position; moving the latch past the latch receiving device and the door to the closed position; and decompressing the spring and moving the latch back to the locked position.

6. A method for securing the cargo on a cargo transport vehicle having a container and cargo door accessible from the outside for closing the container and being movable from an open position to a closed position, the method comprising: providing a latching device, having a latch, on the inside of the container; providing a latch receiving device, adapted to receive the latch, on the inside of the container, the latch being movable between a unlocked position and a locked position; providing a controller that controls the movement of the latch between the unlocked position to the locked position; providing a signal generation device capable of sending signals to the controller; providing a memory coupled to the controller; sending a control signal, selected from a lock control signal and an unlock control signal, from the signal generation device to the controller, the unlock control signal indicating that the latch should be in the unlocked position and the lock control signal indicating that the latch should be in the locked position; and storing, in memory, control data indicative of the most recent control signal sent from the signal generation device to the controller.

7. A method as defined in claim 6, further comprising providing a transmitter coupled to the controller and transmitting the control data to a remote location.

8. A method as defined in claim 6, further comprising: providing a latch sensor coupled to the controller; sensing, with the latch sensor, whether the latch is in the locked or unlocked position; sending a latch position signal indicative of whether the latch is in the locked or the unlocked position to the controller; and moving the latch from its unlocked position to its locked position if the signal generation device sends the lock control signal to the controller and the latch position signal indicates that the latch is in the unlocked position.

9. A method as defined in claim 6, further comprising: providing a latch sensor coupled to the controller; sensing, with the latch sensor, whether the latch is in the locked or unlocked position; . sending a latch position signal indicative of whether the latch is in the locked or the unlocked position to the controller; and moving the latch from its unlocked position to its locked position if the memory indicates that the most recent control signal sent from the signal generation device to the controller was a lock control signal and the latch position signal indicates that the latch is in the unlocked position.

10. A method as defined in claim 6, further comprising: providing a latch sensor coupled to the controller; sensing, with the latch sensor, whether the latch is in the locked or unlocked position; sending a latch position signal indicative of whether the latch is in the locked or the unlocked position to the controller; providing a door sensor coupled to the controller; sensing, with the door sensor, whether the cargo door is in the open or closed position; sending a door position signal indicative of whether the door is in the open or closed position to the controller; and moving the latch from its unlocked position to its locked position if the signal generation device sends the lock control signal to the controller, the latch position signal indicates that the latch is in the unlocked position, and the door position signal indicates that the door is in the closed position.

11. A method as defined in claim 6, further comprising: providing a latch sensor coupled to the controller; sensing, with the latch sensor, whether the latch is in the locked or unlocked position; sending a latch position signal indicative of whether the latch is in the locked or the unlocked position to the controller; providing a door sensor coupled to the controller; sensing, with the door sensor, whether the cargo door is in the open or closed position; sending a door position signal indicative of whether the door is in the open or closed position to the controller; and

moving the latch from its unlocked position to its locked position if the memory indicates that the most recent control signal sent from the signal generation device to the controller was a lock control signal, the latch position signal indicates that the latch is in the unlocked position, and the door position signal indicates that the door is in the closed position.

12. A method as defined in claim 6, further comprising: providing a latch sensor coupled to the controller; if the signal generation device sends the lock control signal to the controller, activate the controller to control movement of the latch from its unlocked position to its locked position; sensing, with the latch sensor, whether the latch is in the locked or unlocked position; sending a latch position signal indicative of whether the latch is in, the locked or the unlocked position to the controller; and if the latch position signal indicates that the latch is in the unlocked position, then activate the controller a second time to control movement of the latch from its unlocked position to its locked position.

13. A cargo transport vehicle comprising: a container and a door, accessible from outside the container, the door being movable from an open position to a closed position; a latching device, having a latch, on the inside of the container; a latch receiving device, adapted to receive the latch, on the inside of the container, the latch being movable between a unlocked position and a locked position; a controller that controls the movement of the latch between the unlocked position to the locked position; a signal generation device capable of sending signals to the controller, the signal generation device capable of sending a control signal, selected from a lock control signal and an unlock control signal, to the controller, the unlock control signal indicating that the latch should be in the unlocked position and the lock control signal indicating that the latch should be in the locked position; and a memory coupled to the controller, the memory capable of storing control data, indicative of the most recent control signal sent from the signal generation device to the controller.

14. A cargo transport vehicle as defined in claim 13, further comprising a transmitter coupled to the controller, the transmitter capable of transmitting the control data to a remote location.

15. A cargo transport vehicle as defined in claim 13, further comprising: a latch sensor coupled to the controller, the latch sensor capable of sensing whether the latch is in the locked or unlocked position and sending a latch position signal indicative of whether the latch is in the locked or the unlocked position to the controller; and a motor powered device that moves the latch from its unlocked position to its locked position if the signal generation device sends the lock control signal to the controller and the latch position signal indicates that the latch is in the unlocked position.

16. A cargo transport vehicle comprising: a container and a door, accessible from outside the container, the door being movable from an open position to a closed position; a latching device, having a latch, on the inside of the container; and a latch receiving device, adapted to receive the latch, on the inside of the container, the latch being movable between an unlocked position and a locked

position; wherein the latch has an end receivable by the latch receiving device, the latch including a plurality of locked flanges adjacent the end with at least two locked flanges projecting out in different directions.

17. A cargo transport vehicle including a cargo container comprising; a cargo door accessible from the outside for closing the container and being movable from an open position to a closed position; a latching device on the inside of the container, the latching device having a latch, a screw for moving the latch between an unlocked position and a locked position, and a motor for turning the screw, wherein the motor turns the screw in one direction and thereby moves the latch from the unlocked position to the locked position and the motor turns the screw in the direction opposite of said one direction and thereby moves the latch from the locked position to the unlocked position.

18. A cargo transport vehicle as defined in claim 17, wherein in order to prevent back rotation, the screw has threads with a small degree of pitch.

19. A cargo transport vehicle as defined in claim 18, wherein the screw has threads with a degree of pitch no greater than 5 degrees.

20. A cargo transport vehicle as defined in claim 17, wherein the motor has a high gear ratio to prevent back rotation of the screw.

21. A cargo transport vehicle as defined in claim 17, further comprising a pre-compressed spring coupled to the latch and the screw for exerting a force to increase friction and prevent back rotation of the screw.

22. A cargo transport vehicle as defined in claim 17, including an optical device for sensing the position of the latch.

23. A cargo transport vehicle as defined in claim 17, including a latch receiving device, adapted to receive the latch, located on the inside of the container, adjacent the cargo door.

24. A method for securing the cargo of the trailer having a container and cargo door accessible from the outside for closing the container and being moveable from an open position to a closed position, the method comprising: providing a latching device on the container, the latching device having a latch; moving the latch between an unlocked position and a locked position; providing a latch receiving device, adapted to receive the latch; sensing whether the latch is in an unlocked position; sensing whether the cargo door is closed; if the cargo door is closed and the latch is in an unlocked position, then stalling a timer; and if the latch is in an unlocked position and the door is closed after a predetermined delay, then moving the latch from the unlocked position to the locked position.

25. A method for securing the cargo of a trailer having a container and cargo door accessible from the outside for closing the container and being moveable from an open position to a closed position, the method comprising: providing a latching device on the inside of the container, the latching device having a latch, a screw for moving the latch between an unlocked position and a locked position, and a motor for turning the screw; turning the screw in one direction to thereby move the latch from the unlocked position to the locked position; turning the screw in the direction opposite of said one direction and thereby moving the latch from the locked position to the unlocked position; providing a pre-compressed spring coupled to the latch and the screw for exerting a force to increase friction and prevent back rotation of the screw.