Abstract:
A device and method of sealing a container comprises a mechanical bolt ( 201 ′) with a circuit disposed thereon. The circuit includes RFID function. When a captivating device ( 203 ) is joined with one end of the bolt ( 201 ′) the RFID circuit changes state and operates to transmit symbolic data. When the bolt is severed or cut off the RFID circuit again changes state and operates to transmit other symbolic data.

Description:
FIELD OF THE INVENTION 
     This invention is generally directed to the field of asset tracking and in particular to the field of electronic seals. 
     BACKGROUND OF THE INVENTION 
     Commercial shipping operations include movement of cargo using intermodal containers. A substantial amount of world cargo transport is completed using these intermodal containers. Presently cargo security is a major concern. One simple means to assure that cargo is shipped intact is to use a seal to secure the doors on a container. The concept here is that if the seal was put in place by a trusted source at an origin location, and it remains intact at an intended destination location that the cargo is intact and in fact safe. Prior art includes many types of mechanical seals. One problem with these mechanical seals is that they require manual inspection which is relatively expensive, inconvenient and slows down transport. Electronic seals using Radio Frequency Identification (RFID) technology are also available but are prohibitively costly and moreover complicated to use because operators need to be retrained to use this new technology. Also electronic seals are bulky devices because they contain relatively large antenna structures. As a result benefits of electronic seals, including readability while cargo is in motion, have not been realized. 
     What the intermodal container transport industry needs is an electronic seal that is simple to use without changing operator convention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. 
         FIG. 1  is a diagram of a rear door of an intermodal container; 
         FIG. 2  is an illustration of a conventional bolt seal for sealing an intermodal container; 
         FIG. 3  is a detailed view showing operation of a door opening mechanism on an intermodal container; 
         FIG. 4  shows a conventional bolt seal sealing a door opening mechanism on an intermodal container; 
         FIG. 5  illustrates a different view of the mechanism shown in  FIG. 4 ; 
         FIG. 6  shows an electronic seal in accordance with an embodiment of the invention; 
         FIG. 7  is a diagram illustrating a cross sectional view of the article introduced in  FIG. 6 ; 
         FIG. 8  shows an electronic seal in accordance with another embodiment of the invention; 
         FIG. 9  illustrates an electronic seal in accordance with another embodiment of the invention; and 
         FIG. 10  illustrates a flow diagram describing an asset sealing method in accordance with an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of method steps and apparatus components related to methods and apparatus for electronic seals. Accordingly, the apparatus components and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Thus, it will be appreciated that for simplicity and clarity of illustration, common and well-understood elements that are useful or necessary in a commercially feasible embodiment may not be depicted in order to facilitate a less obstructed view of these various embodiments. The structure described below overcomes the deficiencies of the prior art by providing an electronic seal that looks, feels, and is installed like a conventional mechanical bolt seal. 
       FIG. 1  is a diagram of a rear door of an intermodal container. Intermodal containers are largely defined by the International Organization for Standardization (ISO). A rear door assembly  101 , includes a door  103  opened and closed using handles  105  each connected to a lock shaft  107  connected to a locking mechanism  109 . Note that the handle  105  is captivated by a lock hasp  111 . A seal mechanism is typically inserted into the hasp  111  to prevent the handle  105  from being used to open the door  103 . Note also that the container is identified by a unique license plate number  113  in accordance with an ISO standard. 
       FIG. 2  is an illustration of a conventional bolt seal for sealing an intermodal container. There are many variations on bolt seals but the device is very common. The bolt seal comprises a bolt  201  and a captivating portion  203 . Note that the captivating portion  203  typically has a unique serial number identifier (not shown) that is used by various entities in the transportation system. 
     Next, operation of a door opening mechanism on an intermodal container is described in  FIG.3 . A lower hasp mechanism  111 ′ cradles the handle  105 . To open the container door an upper hasp mechanism  111 ″ is rotated allowing the handle  105  to be lifted up from the lower hasp mechanism  111 ′. Once the handle  105  is lifted sufficiently an operator pulls the handle  105  away from the container door causing the lock shaft  107  to rotate about an axis  303 . After sufficient rotation the locking mechanism  109  shown in  FIG. 1  is opened allowing the door  103  to be opened. In practice both handles shown in  FIG. 1  associated with the door  103  must be used to open the door  103 . 
     Referring now to  FIG. 4  the bolt  201  is inserted through the upper hasp mechanism  111 ″, the lower hasp mechanism  111 ′ and captivated by the captivating portion  203 . The container door  103  shown in  FIG. 1  is now sealed. Both the head of the bolt  201  and the breadth of the captivating portion  203  do not allow the removal of the bolt seal. To remove the seal one must use a bolt cutter or other equivalent device to sever the bolt allowing it to be removed from the upper hasp mechanism  111 ″ and the lower hasp mechanism  111 ′. 
       FIG. 5  illustrates a different view of the mechanism shown in  FIG. 4 . Again the bolt  201  is inserted through the upper hasp mechanism  111 ″, the lower hasp mechanism  111 ′ and captivated by the captivating portion  203 . 
       FIG. 1  through  FIG. 5  illustrate industry convention. Various embodiments illustrating the improved device and method will be detailed next. 
       FIG. 6  shows an electronic seal in accordance with one embodiment of the invention. A bolt  201 ′ serves as the base material for hosting electronic components on a substrate  601  along a longitudinal surface of the bolt  201 ′. However, skilled artisans will realize that in other embodiments, electronic components may be disposed along other surfaces of the bolt  201 ′ such as, for instance, in the head of the bolt  201 ′. The bolt  201 ′ can be made of many different materials but here is a conventional steel material. The bolt  201 ′ has a captivation feature  603  disposed thereon for locking an electrically conductive article  605  and permanently affixing the captivating portion  203  onto the bolt  201 ′. Article  605  is shown apart from the captivating portion  203  for clarity of operation only. However, article  605  is typically captivated within the captivating portion  203 . Those of ordinary skill in the art will readily recognize many other functionally equivalent means for permanently affixing the captivating portion  203  onto the bolt  201 ′. 
     Turning now to the substrate and associated components and elements, substrate  601  is in one embodiment made of a standard FR4 printed circuit board material or a polyimide or other flexible substrate. Of course other suitable materials may be used. In this embodiment shown in  FIG. 6 , components affixed to the substrate  601  comprise a battery  611 , an integrated circuit  613 , and other electrical components  615 . These other electrical components  615  can include a magnetic wakeup circuit. Circuit traces  607  and  609  are also disposed longitudinally on substrate  601  and extend into a portion  621  of the substrate  601 . One key principal here to recognize is that because the article  605  is electrically conductive, circuit traces  607  and  609  that are disposed on the substrate  601  are electrically connected upon the captivation feature  603  engagably locking the article  605 . In this arrangement, circuit traces  607  and  609  form a plurality of electrically separated conductors arranged at one end of the circuit substrate  601 . Moreover, the action of onserting the captivating portion  203  to the bolt  201 ′ activates the electronic seal. The seal then commences operation. There are only two traces  607  and  609  shown in the embodiment illustrated. However, those of ordinary skill in the art will realize that additional traces may be used in other embodiments. 
     Referring briefly to  FIG. 10 , it illustrates a flow diagram describing an asset sealing method in accordance with an embodiment of the invention. The components  611 - 615  provided for on the bolt  201 ′ form an active radio frequency identification device (RFID) (step  1001 ) and are arranged to sense the electrical connection of circuit traces  607  and  609  and to change a state of the RFID device based on this sensing, when the captivating device  203  is attached to bolt  201 ′ (step  1003 ). This change of state may cause commencement of beaconing a unique identification symbol using antenna elements  617  and  619 . In one embodiment, other information—such as the seal state, here “closed” of the device—is transmitted as well. Also information such as time of closure can be transmitted. Many other functional operations are possible as well. For example after electrical connection of circuit traces  607  and  609 , the RFID device can also remain dormant until an external stimulus is received via the antenna elements  617  and  619 . If the external stimulus is received by the RFID device then it can start transmitting the unique identification symbol for a period of time. Those of ordinary skill of the art will readily recognize many other useful RFID functions. RFID readers (not depicted here) can sense the transmissions and pass them onto other external systems to monitor the seal-state of the container. 
     In this embodiment, the substrate  601  is at least partially wrapped around the cylindrical geometry of bolt  201 ′. This feature is shown at reference number  621 . Since the shorting device, article  605 , is circular this enables more convenient conformance around the captivation feature  603 . The antenna elements  617  and  619  are correspondingly wrapped helically around the cylindrical bolt  201 ′. By doing this the emitted radio frequency (RF) energy is emitted in all directions rather than in a single direction. Of course other antenna arrangements can be used to achieve a substantially similar result. Antenna elements  617  and  619  can be constructed of conventional copper wire, printed or otherwise deposited conductive elements, flexible circuit substrates, or other equivalent means. 
     When a cutting device is used to remove the bolt  201 ′ it also cuts through the circuit traces  607  and  609  (shown by reference number  625 ) if cut proximate the captivating portion  203 , which affects another state change in the RFID device, e.g., seal state is “opened” (step  1005  of  FIG. 10 ). Alternatively the cutting device can be used to cut through another circuit trace positioned  623  distal the captivating portion  203 . In either case the RFID circuit senses this and either stops transmitting the unique identification symbol and seal state, or transmits that the seal state is “opened”. 
     To finish the device a protective overcoat can be applied except for the circuit traces  607  and  609 . One such coating is Polyamide or other nylon based material which can be easily over molded. This over molding will protect the device from harsh chemical environments such as salt water experienced by intermodal containers during overseas transit. 
       FIG. 7  is a diagram illustrating a cross sectional view of the article introduced in  FIG. 6 . Here the RFID components  611 - 615  are shown positioned coaxially within the bolts  201 ′ external extents in a slot  701  removed from the bolt&#39;s cylindrical geometry. This is a useful arrangement because the earlier described upper and lower hasp mechanisms  111 ″ and  111 ′ have openings of a slightly larger diameter than the diameter of the bolt  201 ′. So by containing the RFID components essentially within the outer extent of the bolt diameter the described device can still be threaded through the conventional hasp elements. Once over molded the bolt looks and works like a conventional mechanical bolt seal with a protective coating disposed thereon. 
       FIG. 8  shows cross sectional view of an electronic seal in accordance with another embodiment of the invention. In this case another slot  801  is removed from the bolt&#39;s cylindrical geometry to create a second area for housing additional electronic components  803  and  805 . Circuit substrate  605 ′ is extended at least partially around the bolt  201 ″ to host the additional circuit elements. Since the bolt diameter is constrained and the bolt length is also constrained (to make it harder to bend of illicitly), adding more space for circuitry enables more function to be contained within the extents of the cylindrical bolt. 
     In  FIG. 9  a cross sectional view of another embodiment of the invention includes adapting the circuit elements including the circuit substrate  605 ″ to the surface of the bolt. In this case the circuit substrate  605 ″ is wrapped around a rectangular portion of the bolt. The height of the components  611 - 615  are constrained to be within the external extents of bolt  201 ″ to better enable the bolt  201 ″ to be inserted through conventional hasp elements without damaging these components. 
     In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued. 
     Moreover in this document, the terms “comprises,” “comprising,” “has”, “having,” “includes”, “including,” “contains”, “containing” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, has, includes, contains a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a”, “has . . . a”, “includes . . . a”, “contains . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises, has, includes, contains the element. The terms “a” and “an” are defined as one or more unless explicitly stated otherwise herein. The terms “substantially”, “essentially”, “approximately”, “about” or any other version thereof, are defined as being close to as understood by one of ordinary skill in the art, and in one non-limiting embodiment the term is defined to be within 10%, in another embodiment within 5%, in another embodiment within 1% and in another embodiment within 0.5%. The term “coupled” as used herein is defined as connected, although not necessarily directly and not necessarily mechanically. A device or structure that is “configured” in a certain way is configured in at least that way, but may also be configured in ways that are not listed.