The system described here is a bolt-type seal lock which includes a bolt, having a U-shaped shaft with first and second end portions; and a locking body having a passageway therethrough with first and second open ends on opposite sides of the locking body for receiving the first end portion of the shaft of the bolt, and an opening for receiving the second end portion of the shaft of the bolt. The locking body is configured to receive and retain the shaft in locking engagement; and the locking body is configured to permit passage of the first end portion of the shaft through and out of the second open end of the passageway, and withdrawal of the second end portion of the shaft from the opening.

TECHNICAL FIELD

The invention disclosed here generally relates to shipping container security systems. More particularly, it relates to shipping container security systems that provide both security and shipping information at the same time.

BACKGROUND OF THE INVENTION

Large numbers of containers are used to ship goods on a worldwide basis. Container shipping creates issues relating to both supply chain management and security. For a supply chain manager, having instant access to information that identifies a container's whereabouts is important for both inventory management and predicting customer delivery. Container security is obviously important from the standpoint of knowing whether or when security is breached.

Shipping containers are manufactured according to international standards that have encouraged generically designed containers that can be carried by ships, handled at international ports, and easily transferred to truck or rail. Container doors are typically sealed for security purposes. However, it is relatively easy to breach container security by either cutting the door seal; bypassing the seal entirely by cutting or removing door hasp structure; or by simply cutting a hole through the side of the container with a cutting torch.

Because of the sheer volume of containers in use today, it is not practical to physically inspect each one as they cross borders or change hands from one shipper to the next. It is estimated that only 2 to 3% of containers are physically inspected when they enter the United States (“U.S.”), for example.

Container security is obviously a problem before entry into the U.S. in the first place. However, once inside the U.S., containers are often temporarily stored in various transit locations where they can be accessed and broken into (transit centers, railyards, etc.). All of these various factors create an ongoing situation where a security breach is often not identified or recognized until the container reaches the destination where it is supposed to be unloaded.

It is presently not possible to prevent unauthorized entry into a container. However, knowing whether a container has been entered (whether entry is authorized or unauthorized), when it was entered, and where, is useful information to a shipper, over and above simply keeping track of the container's location on an ongoing basis. The system described here provides a different arrangement of components for providing the means to monitor container security along these lines.

The replacement costs for bolt-type seal locks is an ongoing issue for those shippers who handle large numbers of containers. Leaving aside the ongoing expense of cutting and discarding bolt-type seal locks when a container reaches its final destination, there are many legitimate reasons why the bolts need to be cut at an earlier point in time, for temporary entry into the container, due to customs inspections or other supply chain reasons. Therefore, in addition to describing an overall security system, what also follows below an improved design for the mechanical aspects of the locking structure in the seal lock—that enables bolt-type locks to be cut and reused or recycled at the place where they are cut.

SUMMARY OF THE INVENTION

The invention disclosed here is an improved bolt-type seal lock and security system for use with shipping containers.

The bolt-type seal-lock described here has a conventionally-shaped bolt with a head that is inserted into a locking body. The bolt's head is wider than the end so that the bolt cannot be pulled through a hasp or similar locking structure on a container door, once the bolt is inserted into the locking body.

The locking body has a passageway for receiving the end of the bolt and holding it in place—which is typical to bolt-type seal locks. However, in this instance, the passageway extends all the way through the length of the locking body so that, when the bolt is cut, the bolt's cut end can be pressed or pushed out through and from the locking body. The internal locking structure permits this without changing or having to replace any other internal locking components, other than the bolt itself, and an ID tag that is included as part of the overall seal lock module. As a consequence, a container can be opened and relocked by an inspector so long as the inspector has a replacement bolt and ID tag, as per the design described here.

The bolt has a pre-printed serial number that matches the serial number on the ID tag. The bolt itself additionally carries an electronic circuit and a chip that has the serial number electronically stored on it. This information is transmitted to a memory storage device that is attached to the bolt-type seal lock—either directly or indirectly in ways that are described below. The electronic circuit (on the bolt) enables a signal to be generated or created when the bolt is cut and/or for the chip to transmit the next serial number to be read into memory when a new bolt is installed.

The bolt and locking body design described here could be used independently on a stand-alone basis. However, it is also described here as a part or component of a module, or an “electronic seal lock module,” that is mounted to the outside of a shipping container. The electronic seal lock module, as a unit, is intended to replace the conventional bolt lock in use today and serves as both the locking mechanism for the door and a source of electronic information of all kinds. Therefore, the electronic seal lock module creates a unique, microprocessor-based unit that has both physical locking and data storage capability. It may be built to include a variety of sensors for detecting environmental conditions external to the container body, such as motion and vibration, temperature and humidity, if desired.

The module's data storage capability is in the form of flash memory, or something equivalent, and enables the module to store sensor data on an ongoing basis, as well as storing bolt and ID tag serial numbers, shipping information, customs documentation, computer applications, audio and visual files, or any other form of computer data files. Most importantly in terms of the security function this design provides, the module's data storage capability allows it to store bolt serial numbers, as bolts are installed, or store information about when each bolt is cut.

As indicated above, the physical locking portion of the electronic seal lock module (i.e., the bolt and the bolt's corresponding locking body) is an improved version relative to what was described in the '300 application. Nevertheless, the bolt and locking body appear to be conventional on the outside, leaving aside any applicable electronics component. That is, the locking body has an opening for receiving the end of the bolt and an internal locking mechanism, within the locking body, for engaging with the bolt's end. What is outwardly different is that the locking body is connected to an electronics box by means of a rotational pin (that is, the locking body and electronics box integrate together to create the complete seal lock module).

As described above, the bolt itself carries an electronically addressable serial number circuit that assigns a unique serial number to each individual bolt. Upon insertion of the bolt into the locking body, the electronic serial number is automatically identified, or read, and logged into a data storage device that is integral to the electronic seal lock module as part of the electronics box attached to the locking body. Once installed, the only manner in which the bolt can be removed is to cut the head off the bolt. After the head is cut, the remnant of the bolt may be pressed through the locking mechanism (inside the locking body) and out the bottom of the lock housing, thereby preparing the lock for insertion of a new bolt. Cutting the bolt also cuts the electronic circuit just described. This is a detectable event that can similarly be logged in data storage inside the electronics box.

Another optional component of the system is a separate and independent “container” sensor electronics module that is mounted to the inside of the shipping container. This optional electronics module is physically independent of the electronic seal lock module mounted to the door, although both modules, or system components, would wirelessly interact with each other if both are used at the same time.

The container sensor electronics module has either an internal or external antenna (whether it is internal or external depends on specification security application or need). Like the electronic seal lock module described above, the container sensor module is a microprocessor-based unit with its own data storage capability—which means that it is essentially a redundant unit to the electronic seal lock module. However, in contrast to the electronic seal lock—which is mounted as a lock to container door structure on the outside—the container sensor electronics module may contain a variety of sensors for detecting environmental conditions inside the container such as motion, vibration, impact, temperature, humidity, presence of light, or nuclear and biological material detection devices (to detect unauthorized access and placement of dangerous materials for security reasons), if desired.

As just indicated, each of the two modules described above (i.e., the electronic seal lock module on the door and the container sensor electronics module on the inside) are redundant in that each contains or receives rewritable data storage devices within the body of the module. These devices enable the modules to store the same shipping or transportation data, as well as any sensor or other applicable data electronically, in the manner described above, as the modules travel with the shipping container.

Each module can be individually addressed by means of an external reader or handheld device, if desired. However, since each of the two modules also contains a wireless modem that allows for data exchange between the two modules, downloading information from one module will include any information that is uniquely generated by the other. Moreover, either one of the two modules, or perhaps even both, could function as the overall control device for a container electronics suite (i.e., either one could be a master or slave) if these modules are integrated together as a system intended to function with each other, or with a broader network (e.g., a satellite uplink to a central data base).

Another optional component of the system is a RF-based wireless communications radio for creating a short-range link to a similar radio contained within the “container sensor electronics module.” This link activates when the container door is closed and serves to provide an independent alarm if the door is opened without correct authorization from the sensor module. In other words, this link indicates opening and closing movement of a container door regardless of what happens with the bolt on the door. The RF door alarm module is specifically coded with the container sensor module so that outside devices cannot “spoof” the connection and bypass the door alarm such, as can be the case with the commonly used magnetic proximity detectors or physical switches.

Finally, in accordance with the various system components described here, it is possible to use either the electronic seal lock module or the container sensor module as part of a system that creates a method for transmitting data from a shipping container that is stacked within a group of shipping containers to a receiver outside the group of shipping containers. When large numbers of metal containers are stacked together, the metal in the containers will interfere with the transmission of wireless signals from those containers buried deeply within the stack. In this instance, either the electronic seal lock module or the container sensor module creates a wireless transceiver for each shipping container. These individual transmitters can be networked together so that any data resident with a specific shipping container that is stacked or buried deeply within the group can communicate to a reader on the outside of the group by relaying the wireless connection through other containers that are stacked closer to the outside of the shipping container stack. From the external reader, the information may be relayed over conventional data transmission sources such as satellite communications modems, cellular data networks, wired or wireless networks, or through standard wireless modem connections.

Further details of the components summarized above are disclosed and described below, with the following text to be read in conjunction with the attached drawings.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings, and first toFIG. 3, shown generally at10is a seal lock that is an improved version of the seal lock disclosed in the '300 application. Like the older one, the improved version10has a bolt12and a locking body14. The bolt12is a hardened bolt, with further details of the bolt to be described below.

In this instance, relative to the '300 application, the locking body14illustrated here has a modified housing made from a single piece15of extruded aluminum (seeFIG. 4). There may be other and better ways to manufacture the housing15for cost reasons, which may result in the housing being made from different materials. However, the specific method of manufacture and materials used are not particularly relevant to the various components described here.

The body14has an end plate16on the upper side (seeFIGS. 6 & 7) that receives the bolt12and a second end plate18on the opposite side. The second end plate18may swivel about pivot20to allow access into the seal lock's housing14(seeFIGS. 4 & 6).

A metallic ID tag, generally illustrated at22inFIG. 7, is used in the same way here as in the '300 application. However, in this instance, the ID tag22does not cover access to a locking spring inside the seal lock10. Instead, it simply provides a way for re-marking a serial number on the locking body14, when the seal bolt10is recycled (after the bolt12is cut) and a new serial number is needed for the corresponding serial number on the replacement bolt.

In this new embodiment, the internal locking structure has been altered relative to the '300 patent. The bolt12is held in place by a snap ring24(seeFIGS. 4 and 5). The snap ring24is retained or held in place on one side by a hollow cylinder26and on the other side by a threaded plug28.

The hollow cylinder26is slipped or slid into the housing through a bore30and held in place by either press-fitting or gluing it permanently in place. In this improved version, after the bolt12is cut, the seal lock10is refurbished by pressing the remnants of the bolt12past the snap ring24and out the bottom side of the housing, at30. The cylindrical bore30provides a passageway from end-to-end through locking body14for this purpose.

The ID tag22is also replaced with a new one having a serial number that matches the replacement bolt. The ID tag22slides into the housing15in the same way previously described in the '300 application. It might be held in place by a very low strength adhesive so that it does not fall from the housing prior to use. In use, the bolt12is inserted in the housing15and a shoulder32on the bolt (seeFIG. 5) holds the ID tag22in place, in the same way previously described in the '300 patent application.

The above design represents a departure from the '300 patent application in that it essentially enables the bolt portion of the seal lock10to be “recycled” by the person who cuts the lock, if desired. The shoulder32is created by a plastic cover33that surrounds the hardened metal portion35of the bolt12(seeFIG. 13for example; andFIG. 5). The snap ring24, which prevents the bolt12from being pulled from the locking body14after insertion, will ride over the sloped part37of the bolt's end, as the end is pushed out through the bottom of the housing, as indicated at30. The bolt12is obviously cut somewhere above that point, to sever the bolt's head39from the rest of the bolt. When that happens, the remnants of the sheath33shear away from the metal part35of the bolt as the bolt is pushed down through the housing (seeFIGS. 10 and 11, for example). This, of course, also shears away plastic shoulder32, which normally holds the ID tag22in place.

After the user removes the bolt12in the above way, all the user needs is a new bolt and ID tag to reinstall the seal lock10on the container. The user can be provided with replacement packages of bolts and matching ID tags (the bolt and ID tag serial numbers matching, that is, as shown at41A and41B inFIG. 7), for the purpose of “recycling” the same seal lock10in a rail or shipping yard, or any other location where it is desired to open and then reseal a shipping container. The instant design, also provides a way to automatically identify when the bolt12is cut and/or to identify the serial number of the replacement bolt when it is installed. This will be described further below.

In the design described here, the locking body's housing15is enlarged slightly to carry a larger internal electronics module34(seeFIGS. 4 and 5, for example). Like in the earlier version, the lock seal's electronics module34may include a flash memory for data storage, in the same way previously described in the '300 application. In this instance, however, the electronics module is further equipped with conventional wireless capability as an option, as schematically indicated at35inFIG. 23. This type of functionality is easy to implement via a standard 2.4 GHz modem that runs at low power levels. A power source will be included with the electronics module34. Components like the electronics module34are easy to obtain on a customized basis from companies like Cypress Semiconductor in San Jose, Calif.

As will be further described later, the mechanical bolt-type seal lock10attaches to a cast aluminum housing43(which serves as an electronics box) that completes the entire electronic seal lock module (the complete electronic seal lock module is indicated generally at45in the various Figs.). As previously indicated, the electronic seal lock module45functions as the lock for a container door. How the electronics housing43connects to and integrates with the seal bolt10to create the overall electronic seal lock module45is best seen inFIGS. 8 and 9, with an exploded view also being presented inFIG. 12.

The box43contains an electronics board47powered by a battery pack49. The electronics board47carries a wireless modem that enables the electronics seal lock module45to communicate with various other components of the system described here.

Referring now toFIGS. 1 and 2, the electronic seal lock module45generally provides overall control and system functionality as will be described in additional detail below. It will have its own microprocessor based processing capability for handling sensor information and data of all kinds, which includes its own flash memory that is independent of any flash memory contained within the housing15of the locking body14(i.e., electronics module34) on the bolt-seal10. All of these various components inside the electronic seal lock module45, including environmental sensors (temperature, humidity, impact or shock, etc.) can be placed on the electronics board47, inside housing43.

The housing43itself is made from two aluminum or plastic castings51,53that form a weathertight housing or box in which the electronics board47and batteries49are contained. The housing43also carries permanent magnets55that connect the housing to the face of the container door74, just below the door's locking handle73(seeFIGS. 1 and 2).

The bolt portion10of the electronic seal lock module45is free to rotate about a pin57relative to the weathertight box or housing43, so that the bolt12can be easily placed through corresponding holes in container door handle and related structures, all of which are conventional in design and would be familiar. The magnets55then connect the module's housing43to the container door74so that it does not swing during container transport.

Referring toFIG. 11, the electronic seal lock's wireless capability is provided by two wireless antennas59and61that protrude from upper and lower sides of housing43. These antennas are integrated with the interior electronics board47(seeFIG. 12).

A set of wires (not shown in the figures) will extend from the electronics board47, through a sealed hole in the side of the housing43, and into a corresponding hole in the side of the seal lock body14. These wires will terminate in two spring pin contacts63,65(seeFIGS. 16 & 17) that reside just below the top part of the ID tag22when it is in position in lock body14. This location can be seen at67inFIG. 7. These spring pin contacts63,65are positioned so that, when the bolt12is inserted into the locking body14, they make electrical connection with two annular contact patches69,71on the end of the bolt (seeFIGS. 16 & 17).

The annular contact patches69,71are made from a flexible circuit board material that is die cut into a shape to match the contour of the bolt15(see, generally,75inFIG. 15). The flexible circuit board75is fabricated using common circuit board fabrication techniques with the two above mentioned annular contact patches69,71terminating in two circuit leads that traverse the length of the flexible circuit board75and are then bridged by a silicon microchip77. The silicon microchip77electronically contains the serial number of the bolt12(see41inFIG. 14).

When the bolt12is assembled, the annular contact patches69,71are placed on the exposed metallic end79of the bolt so they are not covered by the bolt's plastic cover33. The remaining part of the flexible circuit board75(and the microchip77) underlies the plastic cover such that it is not normally visible. Subsequent insertion of the bolt's end into the bolt's locking body14(to the point where it is captured by snap ring24(the position shown inFIG. 5, for example)) brings the annular contact patches into electrical connection with the spring pin contacts69,71. This sets up an electrical circuit with the electronics board47inside the electronics housing43of the electronic seal lock45so that the bolt's serial number (electronically stored in the microchip77) is transmitted into data storage on that board. In this way, the serial number of the bolt is “read” and stored at the time it is inserted. Moreover, the electronics board47in the module45continuously monitors this connection. Thus, when the circuit connection is terminated, due to cutting of the bolt12, or for any other reason, this event is recorded by the electronics board47and stored in memory for later reading or transmission.

Electronic schematics for the board47would not be needed to construct it. This type of board, along with the various sensor functions described here, and the wireless capability (typically a 2.4 GHz wireless modem—with the signal output via the antenna blocks59,61) can be easily custom built as a fully integrated unit by companies such as TeraHop of Alphareta, Ga. One only needs to understand the concept of wanting to incorporate sensors capable of sensing desired data concerning environmental conditions on the outside of the container, and wireless and storage capability. TeraHop manufactures integrated electronics of this kind.

An optional component of the system described here is a container sensor electronics module, generally indicated at38(seeFIG. 19), which is mounted to the container36. This optional module is made from two aluminum extrusions40,42that are snap-fit together. The container sensor module38is mounted to a cross-wise door beam44on the container (seeFIG. 20and is adhered by using a pressure sensitive adhesive (“PSA”) on surfaces46,48. When the unit38is first installed on the container36, the PSA covering is removed from attachment surfaces46,48, and the extrusion is spread apart and placed on beam44. Releasing the extrusion causes spring forces to press the PSA into the door beam44. Once again, this mounting arrangement is best seen inFIG. 20, which depicts a corner cross-section of the container36and door structure.

The PSA-carrying surfaces46,48are snap-fit to other parts of the electronics module38. This allows the module38to be disconnected from the container beam44, while leaving the surfaces46,48in place, so that the module38can later be remounted to the container. Removal of the module38from the container is necessary from time to time to replace the battery52, or to gain access to an electronics board module52and an antenna block54on opposite sides of the module38(seeFIG. 19). This particular embodiment shows a single, exterior antenna block54. However, the container electronics module38could be built with an interior antenna or both interior and exterior antennae, if desired.

The battery pack50is a typical two-cell battery pack that uses lithium cells capable of providing 3.6 volts output at 5000 milliAmps. The electronics board module52, inside the container sensor module38, is a combination of electronics that includes specific sensors and digital data storage, similar to the seal electronics module45that locks the container door74. Therefore, and referring now toFIG. 23, this electronics board45includes wireless transmission capability56(provided by a 2.4 GHz wireless modem—with the signal output via the antenna block54), flash memory58for data storage (8M, typical), and humidity60, temperature62, and impact or vibration sensors64, for detecting these conditions inside the container36. It is to be appreciated that the electronic seal lock module45contains a similar set of sensors inside box43, for the purpose of sensing environmental conditions at the door on the outside of container36.

The electronics board52also has low power RF capability66for a door security sensor (explained further below), and may be modified to include still another sensor68that is capable of detecting changes in ambient light (i.e., daylight) inside the container. In other words, a change in interior lighting can be detected when the door is opened, under any circumstance, or if light should enter the container in some fashion because a hole is cut through a sidewall or roof. As previously indicated when the electronic seal lock module45was described above, the type of electronics unit52just described (for use in the container sensor module38) is available on a customized basis from companies like TeraHop Networks, Inc. in Alpharetta, Ga.

Returning toFIG. 19, the electronics board52is connected to the antenna block54by a conventional ribbon cable70. The ribbon cable is protected by covering it with PSA or similar material, which is not shown in the drawings. The antenna block54enables wireless data communication with a satellite uplink, or with a local area network, and also provides an RF link with an active RF door seal module72(seeFIG. 18) mounted to the container door74.

With respect to wireless networks, and referring again toFIG. 23, each electronic seal lock module45on a shipping container36will be in wireless communication with the container sensor electronics module38mounted to the shipping container. The electronic seal lock module45administrates the container sensor module described above, in preferred form (although it could be done the other way with the container module functioning as the administrator or the “master”), and stores shipping data, and stores and administrates other kinds of useful data a shipper may want or need. While data could be transmitted from any one of the three antenna sources described above (that is, the electronic seal lock45; the sensor container module38; and/or a third wireless antenna in the electronics module34inside the seal bolt's locking body14), it is anticipated that the electronic seal lock45will provide the preferred transmission source. Therefore data of all kinds will be transmitted from antenna blocks59,61on the housing43of the electronic seal lock (seeFIGS. 8-11) to a centralized data base88via a satellite uplink84,86as indicated inFIG. 22.

And, once again, as schematically indicated inFIG. 23, in addition to transmitting data to a centralized database, via an uplink, the antenna blocks59,61also enable the electronic seal lock module45to communicate with the wireless modem56inside the container sensor module38. This enables virtually all of the data available in the electronic seal lock module45to be communicated to and exchanged with the container sensor module38on an ongoing basis.

Shipping information, for example, may be easily downloaded from the seal lock45by a handheld device, and even via a USB port76on the locking body14, if desired, in essentially the same way as previously described in the '300 application, or by wireless transmission directly from the internal electronics inside the seal lock module45.

By combining the electronic seal lock module45as a component in a larger system that includes the container sensor module38, it expands upon the type of useful information that may be communicated and made accessible through the seal lock module45. It is important to understand that any of the data available in the electronic seal lock45is duplicated and resident in the container electronics module38, and it can be done in reciprocal fashion vis-à-vis data acquired by one device being shared with and duplicated by the other. This is important when a security breach arises. While there are different ways of entering a container, the simple fact of the matter is that both authorized and unauthorized container entry is usually accomplished by simply cutting the bolt12on the bolt lock10portion of the electronic seal module45.

When the bolt12is cut by a thief, the seal lock module45may be removed, as well. The container subsequently arrives at the destination with clear evidence of tampering, but possibly with the entire module45missing (which means the electronic data stored in the seal lock is also missing). In the design disclosed here, unless the thief overtly attempts to destroy the container sensor electronics module38, then all of the necessary data will still remain resident with the container when it arrives and, as a consequence, can be downloaded. Not only can conventional shipping information be accessed to identify what is missing from the container relative to what should be there, but it would be possible to determine the time of entry and even the likely location.

Moveover, the antenna block54and59and61on these two container sensor and electronic seal lock modules respectively enable ongoing communication between each electronics module and a centralized data base provider, via the Internet or similar network. This mode of communication is conventional and well-known. In the case of the typical ship that carries containers, the ship is likely to have uplink capability to a satellite. Therefore, if the master electronics module is in ongoing communication with a network, it would be possible to instantaneously transmit data at about the time the container door is opened or another type of unauthorized access is detected.

With respect to door security, when the container door74is closed, the antenna block54on the container sensor electronics module38is in active communication with RF door seal module72(mounted inside the door74). This arrangement is best seen inFIG. 18, which shows a cross-section of the door74closed relative to a cross-section of the container36.

If the door74is swung open, then the resultant lack of physical proximity between antenna block54and door seal module72can be detected and used to generate a signal and data that reflects that the door was opened. As per the previous description, it would be possible for the sensor electronics module38to keep track of “when” and “for how long.”

To describe typical operation of the above system, the container sensor electronics module38is coded to the RF door seal72so that no other RF seal will give a correct response code to that particular electronics module38. When a container is loaded and ready to be sealed, the sensor electronics module38is equipped with a reset or synchronization button (not shown in the drawings) that “reads” and synchronizes with electronic seal lock module45on the door. These two devices are uniquely coded to each other and the container doors are closed.

The seal lock housing43can be provided with a flashing LED indicator that indicates all system components are linked wirelessly together. At that point, the bolt12may be installed on the container door. When seal lock10is installed on the container door74, the electronic serial number provided by the chip17is recorded by both the electronic seal lock module45and the container sensor module38. This is to prevent tampering or replacement of the seal lock10during shipping.

An advantage to the system described here is that it provides an automatic update of serial numbers when new seal bolts are installed. Other advantages include multiple redundancies and also a medium for communicating data from shipping containers that is unique. One type of redundancy lies in using the electronic sensor module45as a data storage device with its own independent wireless transmission capability. This allows the container sensor module38to communicate with its respective seal lock module45on the container36, as described above, but it also enables seal lock modules to communicate with each other, if desired, when multiple numbers of the same type of seal lock are used on stacked containers.

Referring now toFIGS. 21 and 22, it is known to communicate data wirelessly from cargo containers, trailers, railcars, etc. However, when large groups of containers are stacked on a ship80, as shown at82inFIG. 21, the metal walls of the group makes it difficult or impossible to transmit wireless data out through the ship's antenna84from those containers that are buried deeply within the stack. It is possible to use individual electronic seal lock modules45, constructed in the way described here, as communication nodes, or combine them into a nodal communication network as schematically illustrated inFIG. 22. While the signal from an individual antenna on a container buried deeply in a stack may not be strong enough to reach the ship's antenna, it will be strong enough to reach the antenna on a nearby seal lock module45. In this way, location and shipping data can be passed through seal locks, from one to the next as needed, until the data is received and broadcast through the ship's antenna, or a satellite uplink84, to first a satellite86and then to a centralized data base88. In this way, a supply chain manager can locate all of the containers on a ship as needed, even if the container sought by the supply chain manager is covered by many other containers.

Finally,FIG. 24shows further variations of the seal lock relative to the disclosure made in the '300 patent application. This Fig. shows a modified version of the seal lock10where the bolt12is replaced with a standard “U” shaped bolt that is found on padlocks. This variation works in the same way, except that the locking body14is modified to have an opening94for receiving a pin96on the bolt92. The mechanical bolt part may be modified in other ways as well. In this description, the bolt lock10is described as having its own electronics module34. If this component is retained, then it creates a third redundant source for data storage, if desired. It may not be needed when the bolt lock design is integrated with the electronics box43described above. It is likely to be included if bolt locks10are supplied as independent devices and used in essentially the way they have been traditionally used—i.e., the manner described in the '300 application.

It is believed that the system described here will provide many advantages to those shippers who rely on electronic tracking of shipped goods. The foregoing description sets forth the current best description of the invention and is not necessarily intended to limit the scope of the patent right. The designs and embodiments disclosed here are in the process of being improved upon. It is conceivable that, as technology changes, certain components described above may be improved upon, or evolve, without departing from the spirit and scope of the invention and its advantages as described above. Therefore, the scope of patent protection is not to be limited by the specifics of the foregoing description. Instead, the scope of the right is to be limited in accordance with the applicable doctrines relating to patent interpretation.