A sealing system for sealing of doors of transport vehicles with door specific seals FIELD OF THE INVENTION

The invention relates to a sealing system for sealing of doors of transport vehicles with door specific seals, a portable logging device used by the system and to a method to operate such a system

BACKGROUND OF THE INVENTION

The doors of a transport vehicle are often sealed after closure of the doors during a checking procedure (clearance) for this transport vehicle with a seal applied to each of the doors. The seals provide visual indications that the doors are closed at a certain point of time and not have been opened later on. In logistic centers, seals may be applied to doors of trucks, train wagons etc. to provide a visible sign to the receiving center, that the transport vehicle (at least the storage volume for the transported freight) was not opened during transport in case of unbroken seals. The seals shall prevent non- detected non-authorized opening of doors to secure the freight loaded to the transport vehicle. In other cases the sealing procedure is part of a release procedure for transports requiring higher security standards. As an example aircrafts have to be released for being allowed to leave the airport. Open doors during take-off and during the flight are a severe safety problem. Therefore, all doors of the aircraft must be closed and must be checked before releasing the aircraft for taking-off (clearance). Currently one or more airport employees visually check all doors of each aircraft and attach adhesive tape across each closed door at the outer side. The adhesive tape provides a visual indication that the particular door is checked and closed. In parallel the airport employee fills out a paper check list to record in writing the executed check procedure. After completing the check procedure, the paper check lists are archived. The airport has to provide an adapted check list per aircraft type, since the number and the location of doors differs between different aircraft types, which require an enormous administrative effort.

Furthermore to find the location of all doors can be difficult for some aircraft types, because the checking procedure does not support the finding of doors. Already checked doors with attached tape might be opened later. Re-opened doors may eventually stay open unnoticed. The checking procedure is time-consuming. Eventual doubts about the correct execution of the check procedure requires a repeated second check procedure leading to time delays in the clearance of aircrafts for subsequent take-off. The listed disadvantages also apply to other transport vehicles.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a sealing system, a portable logging device and a corresponding method to operate the sealing system avoiding the disadvantages of the state of the art. In particular, it is an object of the present invention to provide a sealing system and a portable logging device improving the security of the transported freight and the transport vehicle, which enables easy handling and recording of the sealing procedure. The object is solved by a sealing system for sealing of doors of transport vehicles comprising at least one door with at least one first electrical contact means and a corresponding door frame with at least one second electrical contact means, where the first and the second contact means are arranged on the same side of the door and the door frame and are electrically connected to build an open electrical circuit, and a seal to be attached to the door and the door frame suitable to close the open electrical circuit between first and second electrical contact means in order to indicate the sealing of the door.

The term "open electrical circuit" denotes a conductive connection between two points, here the first and second electrical contact means, with no return path for the current, also called as not-closed loop. The contrary to the open electrical circuit is a closed electrical circuit or a closed loop giving a return path for the current. The seal according to the present invention provides on one hand a visual indication that the particular door is checked and closed. On the other hand the seal provides a closed electrical circuit indicating electronically a correct sealed door and any re-opening of the door results in a broken electrical circuit formally being closed and subsequently will be detected by the changed electrical properties of the electrical circuit. The seal used in the sealing system according to the present invention enables a double security check of sealed doors: (a) visually by the present seal and (b) electronically by the closed electrical circuit, where the seal is a part of. Therefore the seal according to the recent invention improves the security of the transported freight and the transport vehicle. In case of re-opened doors, the freight of the transport vehicle can be checked again to detect any burglary and additionally any security risk to operate the transport vehicle can be avoided.

Furthermore in case of any doubts, whether a door might be re-opened or not, the status of the initially closed electrical circuit provides a secure prove of the history happened to the door. If the closed electrical circuit was not broken, there was no re-opening of the door. Therefore a time-consuming second check can be avoided preventing time delays in the clearance of transport vehicles, e.g. aircrafts for subsequent take-off. A seal simply attachable to the door and the area around the door is easy to handle.

Attaching a seal to a door is called as sealing procedure in the following, which commonly is executed by a security operator.

In the context of the present invention transport vehicles denote any transport vehicle or essential components of the transport vehicles suitable for applying the seal. The term "transport vehicles" comprises trucks, cars, train wagons, ships, container for container trucks, aircrafts such as airplanes or helicopters etc. The term "doors" comprises any opening, which can be closed and re-opened such as conventional doors (e.g. doors of trucks, cars, and aircrafts), scuttles, portholes, hatchways, tailboards etc. The term "door frame" denotes any area of the transport vehicle surrounding the door, where the door is mounted to.

The first and second electrical contact means may be any suitable means allowing to be electrically contacted with corresponding parts of a seal. The material of the first and second electrical contact means has to be conductive, for example a metal layer, a metal plate or a recess or hole with electrical contacts inside. The shapes of the first and second electrical contact means may be identical. In other embodiments, the first electrical contact means may be shaped differently compared to the second electrical contact means. With a corresponding seal having contact areas to be connected to the first and second electrical contact means, which are shaped differently and adapted to the shape of the first and second electrical contact means, the position of the seal is defined with respect to the first and second electrical contact means. This could be advantageous in case of seals comprising electrical components, where a certain current direction is mandatory. For example the first electrical contact means connected to the negative pole of a power supply has a first shape and the second electrical contact connected to the positive pole of the power supply has a second shape different to the first shape, where the first and second conductive areas are shaped in accordance to the shape of the first and second electrical contact means. The connection between both electrical contact means can be established by a wire or any other suitable conductive connection.

An attachable seal denotes any seal, which enables the fixation of the seal at a certain position on the door and the door frame, in particular on the surface of the door and on the surface of the door frame, in order to electrically connect the first and second electrical contact means via the seal. The attachable seal might be glued, clamped, adhesive attached or otherwise fixed at its desired position. The surface of the door or the door frame can be the outer surface (e.g. in case of doors of aircrafts etc.) or for other purposes the inner surface of the door and the wall of a transport vehicle. In case of doors without a particular frame, the door frame according to the present invention is established by the area around the door. In case of double wing doors, the seal might be attached over both wings of the door, where the wing closed first is denoted as the door frame, while the other door wing closed later is denoted as the door. Alternatively, double wing doors might be sealed by applying one seal according to the present invention for each wing of the double wing door. In this case the seal can be applied onto each of the doors and onto the frame around the double wing doors. The term "to indicate the sealing" may denote any suitable electrical parameter (e.g. via resistance or capacitance), which value clearly indicates whether the electrical circuit is open, closed or broken (re-opened) after closing it with the seal. An electrical parameter corresponding to a closed electrical circuit indicates that this door is checked and closed and that the door was not opened again after checking the door. Additionally, any visual inspection also shows, whether the seal is present and undamaged.

The term "seal" denotes a seal of any shape witch can be attached to a door. The seal may be made of a piece of material such as rubber, metal or plastic or combinations thereof, preferably with further embedded components. The seal may comprise a combination of elastic and inelastic materials. The seal may comprise elastic

components or elastic parts of the seal in order to be usable for different kind of doors having different shapes and sizes. The material of the seal comprise electrical wires and/or electrically conductive layers and/or conductive plates arranged at least partly at the surface of the seal in order to be connected to the first and second electrical contact means.

In an embodiment an indication means is arranged within the closed electrical circuit, preferably arranged in or on the seal, and being activated after closing the electrical circuit, preferably being activated by closing the open electrical circuit, to detect a break of the closed electrical circuit during the activated status of the indication means. The activation of the indication means denotes the action required to start a control procedure, where the indication means recognizes a change of the electrical properties of the electrical circuit to a value significant for a broken electrical circuit, which corresponds to a re-opening of the door after sealing this door. For example, the indication means can be activated manually via a switch, preferably automatically activated after closing the open electrical circuit, or via an external signal. In case of activating the seal with a switch, the indication means have to be accessible for an operator performing the sealing procedure, e.g. with indication means arranged in or on the seal. The sealing procedure is the procedure, where the seals are attached to the doors and door frames in order to seal the doors. The activation starts a continuous or periodic measurement of a certain parameter, where the value of the parameter corresponds to the status of the electrical circuit (open, closed or broken after formally being closed), e.g. the resistance or the capacity value or any other suitable parameter of the electrical circuit. Depending on the embodiment of the indication means, the activation of the indication means might be reversible or non-reversible. In case of nonreversible activation, the system is intended for finally sealing a door. Indication means able to be de-activated by authorized people enable a reversible sealing procedure. However, it has to be prevented that the indication means can be de-activated by non- authorized persons. This could be achieved by a suitable positioning of the indication means at a place not accessible after completing the sealing procedure, e.g. at the outside of aircrafts when the doors can only be re-opened from the inside of the aircraft. However, it is advantageous if the de-activation is only possible for authorized persons, e.g. by a certain mandatory identification procedure authorized people have to perform before being able to de-activate the seal. Preferably, the indication means is arranged inside the seal.

In an embodiment of the sealing system a power supply is arranged within the closed electrical circuit in order to operate at least the indication means. The power supply can be any suitable power supply, e.g. a battery to allow a low voltage driving of the components of the closed electrical circuit, e.g. the indication means and other components such as a light source (e.g. a LED) indicating the activation of the indication means. Such a light source may be arranged at the seal or at any other suitable place near the closed electrical circuit and/or the seal. A light source enables a fast check of a successful activation of the indication means corresponding to a correct sealing of the door, especially during night. In an embodiment, the power supply may be arranged as part of the seal. The advantage of a seal carrying the power source, preferably a rechargeable battery, to operate the electrical circuit, especially the indication means, is the possibility to exchange and/or recharge the battery separate from the door and the door frame before attaching the seal to the first and second electrical contact means. This guarantees a maintained power supply ready for use when sealing the door.

In another embodiment the indication means comprises a sending means, preferably a RFID chip, suitable to send out a warning signal, preferably comprising a code suitable to identify the location of the sealed door, as response to the detected break of the closed electrical circuit. In case of re-opening of the door, the sent-out warning signal could be any type of warning signals suitable of being recognized by either a control system, e.g. a computer system, and/or present people. The sending means may be any means suitable to send-out a warning signal. There are very small and/or flat chips available as sending means on the market today suitable to be integrated into the closed electrical circuit, e.g. located in the door, the door frame or in the seal. An eventually required additional antenna can be arranged for example as a flat antenna. As an example, RFID transponders (RFID chip) are able to provide signals with a large possible operating distance up to 100m. The indication means comprising an RFID chip may be activated (= activation of the closed electrical circuit) by receiving an external activation signal, for example provided by the portable logging device. The required power, e.g. for active RFID tags, to operate the seal may be received from a flat battery arranged as a component in the closed electrical circuit, for example embedded in the seal. In a preferred embodiment, the indication means comprises a clock to record the time, when the break of the closed electrical circuit is detected. It is even more preferable that the warning signal comprises the time, when the break was detected. The warning signal may have any suitable format to be able to be received from a receiving station, e.g. having a Bluetooth or ZigBee format, comprising the code of the broken seal, preferably together with the time, when the control means detected the break or damage of the seal and/or the formally closed electrical circuit. People skilled in the art may consider other sending means within the scope of this invention. The range of operation depends on transmitting power, frequency and receiver sensitivity. People skilled in the art will choose the appropriate sending technology within the scope of this invention. In an embodiment the sealing system further comprises at least one receiving station, preferably multiple receiving stations, arranged within a clearance area to receive the warning signal, preferably further comprising alarm means suitable to provide an alarm signal at least inside the clearance area as a response of the received warning signal. The clearance area denotes the area within a logistic terminal or center, where the transport vehicles are located for releasing the vehicles to transport the freight to the desired destination. The freight comprises goods of any kind and/or people transported by the transport vehicle. As an example, for aircrafts as the transport vehicle, the clearance procedure comprises all necessary steps and components for permitting the aircraft to take-off. Correspondingly the clearance area could be the airport terminal, any other parking area for the aircraft, a hall or the entire airport. In case of other transport vehicles, the clearance area might be a logistics center (e.g. for trucks), a harbor, a train station, a switching yard station or other parts of the previously listed areas. Depending on the range of operation of the sending means and the size of the clearance area, multiple receiving stations are required to receive an eventual warning signal from any possible location inside the clearance area. The receiving stations may be connected to the computer system via a data connection established by data cables or wireless applying a data transmission technology with a larger range of operation or by forwarding the received data from one receiving station to the neighbored receiving stations until the transmitted data can be received by the computer system. The receiving station can be any device suitable to receive the warning signal as a wireless signal, e.g. an antenna. The alarm signal can be a visible, audible signal or a signal provided by the receiving means itself (here the receiving means are also the alarm means) or triggered by a computer system connected to the receiving means and the alarm means recognizable for a security operator inside and/or outside the clearance area. For example, the alarm signal may be send-out by an alarm means such as a horn, a loudspeaker, a flashlight or other alarm means. In another embodiment the sealing system further comprises at least one portable logging device according to the present invention to record the sealing of the door with at least a data insert unit to insert a particular type of the transport vehicles, to record an executed attachment of the seal to a certain door and a data unit to store the data as sealing data. The portable logging device replaces any paper check lists to record the executed sealing procedure such as sealing of doors. The sealing procedure can be executed much faster due to the avoided manually filling of forms. Eventual doubts about the correct execution of the check (sealing) procedure can be resolved by checking the recorded sealing data avoiding a time-consuming second check procedure, which formally led to time delays in the clearance of transport vehicles, e.g. aircrafts for subsequent take-off. Furthermore the portable logging device may be used to activate the indication means.

In another embodiment the indication means or the seal provides a machine-readable code suitable to identify the sealed door and the portable logging device comprises a reading unit suitable to read the machine-readable code and to store the machine- readable code as part of the sealing data in the data unit. The machine-readable code is preferably provided as electromagnetic signal send-out by a RFID chip as part of the indication means. The advantage is an easy logging of the checked (sealed) doors with applied seals. The operator attaching the seals to the doors does not have to fill in check lists manually to log the sealing procedure, but can log the individual code provided by each indication means corresponding to a certain door where a seal is applied simply by a logging device reading the seal identification. The machine-readable code can be any kind of code able to identify the seal (= to distinguish a particular indication means corresponding to a particular closed electrical circuit and therefore to a particular door from all other indication means arranged at other doors) and to be read by the logging device. Alternatively the sealed door can be identified by a machine-readable code attached to the seal, e.g. a barcode label applied (glued) to the outer surface of the seal (outer surface = surface facing away from the door). In another embodiment the sealing system further comprises a computer system suitable for receiving and storing the sealing data from the portable logging device. The computer system can be any system suitable to receive, to store and preferably to archive the sealing data in order to record any executed sealing procedure. The stored data may be used later in case of doubts of an executed sealing procedure, e.g. in case of lost freight. The sealing data may be received via a data port connected to the computer system by a data cable or received wireless, e.g. by a WLAN connection. The advantage of such a sealing system is the easy and fast logging of the sealing procedure, the availability of the logged data to any person having a need to know, the easy archiving of any sealing procedure and the improved security for the transport vehicle and the loaded freight by fast and reliable detection of any non-authorized re-opening of a sealed door.

In another embodiment the seal comprises a first conductive area suitable to be attached to the first electrical contact means and a second conductive area electrically connected to the first conductive area suitable to be attached to the second electrical contact means in order to close the open electrical circuit. The closed electrical circuit comprises the electrical circuit of first and second electrical contact means and the electrical connection between these means and the first and second conductive areas and the electrical connection between these areas. As an example the first and second conductive areas might be connected via a wire arranged inside the seal or via a conductive path at least partly covering the surface of the seal. The shape of the conductive path can be adapted to the particular application within the scope of this invention. The electrical contact between first electrical contact means and first conductive area and second electrical contact means and second conductive area can be established by tightly fixing the seal to the surface of door and door frame, e.g. with an at least partly adhesive surface of the seal surrounding the first and second conductive areas, or any other suitable techniques to fix the seal to door and door frame.

In a preferred embodiment the first conductive area and the first electrical contact means and/or the second conductive area and the second electrical contact means form a suitable combination of mechanically fitting parts, preferably the combination is at least one element of the group of elements comprising plug and socket, recess and protrusion, metal area and spring mounted protrusion, or metal area and magnetic metal area in order to improve the tight fixation of the seal to door and door frame resulting in a reliable closure of the electrical circuit indicating the sealing of the door. People skilled in the art may choose appropriate geometrical shapes and material properties of first and second electrical contact means and conductive areas to establish reliable closure of the electrical circuit. The invention further relates to a portable logging device for recording sealing of doors used in the sealing system comprising a data insert unit to insert a particular type of the transport vehicles, to record an executed attachment of a seal to a certain door, and a data unit suitable to store the data as sealing data, preferably further comprising a reading unit to read a machine-readable code provided by an identification means or the seal and to store the machine-readable code in the data unit, more preferably further comprising a display unit for displaying the location of each door of the particular type of the transport vehicles where the seal has to be attached and for correlating the location of the door with the machine-readable code. In a preferred embodiment the portable logging device comprises a data connection unit suitable to transfer the sealing data to a computer system and/or update the sealing data stored in the data unit, preferably via a wireless data connection. The portable logging device replaces any paper check lists to record the executed sealing procedure. The sealing procedure can be executed much faster due to the avoided manually filling of forms. Eventual doubts about the correct execution of the check procedure can be resolved by checking the recorded sealing data avoiding a time-consuming second check procedure, which formally led to time delays in the clearance of transport vehicles, e.g. aircrafts for subsequent take-off.

The logging device is portable, e.g. as a hand-held device. The data insert unit can be any suitable array of buttons or keys to insert data, e.g. a key board or an array of keys for multiple characters, numbers and/or symbols. The transport vehicles can be very different. Even in the same class of transport vehicles, e.g. aircrafts, there are many different types of transport vehicles, e.g. small aircrafts, large aircrafts, aircrafts of any size from different manufactures etc. having a different number and location of doors. After inserting the type of the transport vehicle the portable logging device may provide the number of doors to be checked for this particular transport vehicle. Alternatively, the portable logging device may count the inserted executed attachments and compares the number to the expected number of doors and to be checked for this particular type of transport vehicle. The inserted data are stored in a suitable data unit, e.g. a memory chip, or a memory card. People skilled in the art may choose other data units within the scope of this invention.

The reading unit may be any suitable reading unit adapted to the provided machine- readable code. In case of a barcode as the machine-readable code, the reading unit is a barcode scanner. If the machine-readable code is coded electronically, the reading unit is an adapted receiver of the send-out code of the indication means or the seal. This machine-readable code together with a portable device able to read the code of the identification means or alternatively of the seal will significantly reduce the required time for the sealing procedure. The operator only has to attach the seal to the door and place the portable logging device for a short moment in a suitable position in front of the sealed door in order to record the executed sealing for this door. This action requires only a minimum of time compared to sealing procedures according to prior art.

The support for the operator to find the doors provided by the display unit is strongly preferred, because the large number of different types of transport vehicles makes it very difficult for the operators executing the sealing procedure to quickly find the doors to be checked. A door difficult to be find may lead to a delay in the clearance of a transport vehicle. Furthermore the operators do not have to be instructed to find doors in beforehand, which require an enormous administrative effort. The display unit may be any suitable display of a suitable size to support the operator to find all the doors of the transport vehicle in a short time period. The location of the doors may be displayed as marker of a displayed lay-out or blueprint of the transport vehicle. The portable device may further comprise a GPS module in order to provide distance and orientation information to the operators in case of very large transport vehicles, such as aircrafts, ships or trains. The combination of marked doors and distance between the current position of the operator and the next door will improve the support to the operator how to find the next door. The location of the door on the layout or blueprint can be correlated to the code of the seal. This correlation will decrease the required time and effort to check a seal in case of receiving the warning signal from the indication means, because the location of the door corresponding to the particular indication means is known.

The data connection unit may be a data port suitable to be inserted in a corresponding reading device connected to the computer system. The wireless connection may be provided by a WLAN system present in the environment of the portable device, where the computer system is connected to. The possibility of transmitting the recorded data via a data connection to a computer system makes archiving of sealing data very easy and fast. Eventual doubts about the correct execution of the sealing procedure can be proven by checking the archived sealing data avoiding a time consuming second sealing procedure.

The invention further relates to a method for operating a sealing system according to the present invention comprising the steps of

- providing at least one door with at least one first electrical contact means and a corresponding door frame with at least one second electrical contact means, where the first and the second contact means are arranged on the same side of the door and the door frame and are electrically connected to build an open electrical circuit, and

- closing the open electrical circuit by attaching a seal to the first electrical contact means of the door and to the second electrical contact means of the door frame in order to indicate the sealing of the door.

In an embodiment the step of closing the open electrical circuit further comprises the steps of

activating an indication means after or by attaching the seal, and

sending out a warning signal by the indication means after detecting a break of the closed electrical circuit during the activated status of the indication means. The step of activating the seal can be executed mechanically by an operator or by attaching the seal to the door via a mechanical switch or electronically by detecting the closure of the formally open electrical circuit or electronically by an external signal provided from a portable logging device.

In another embodiment the method further comprises the steps of

receiving the warning signal with at least one receiving station, preferably multiple receiving stations, arranged within a clearance area, and

preferably providing an alarm signal at least inside a clearance area as a response of the received warning signal.

The alarm signal can be a visible, audible signal or a signal provided by the computer system to a certain security operator.

In another embodiment the method further comprising the steps of

inserting a particular type of the transport vehicles into a portable logging device according to the present invention,

- inserting the execution of attaching the seal to a certain door as sealing data into the portable logging device via a data insert unit, preferably by reading a machine-readable code provided by an indication means, and

storing the inserted sealing data in a data unit of the portable logging

device.

- receiving and storing the sealing data inserted to the portable logging device from the portable device in a computer system as part of the sealing system, preferably via a wireless data connection,

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

Fig.1 : seal system according to the present invention for sealing a door of a transport vehicle.

Fig.2: seal attached to door and door frame: (a) first embodiment 1, (b) second

embodiment.

Fig.3: embodiments of a seal and a portable logging device connected to a receiving station and a computer system.

Fig.4: a sealing system according to the present invention.

Fig.5: different transport vehicles with applied sealing system according to the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Fig.1 shows a seal 4 according to the present invention attached to a door 2 of a transport vehicle 7 in order to seal the door 2. A first conductive area 41 of the seal 4 is attached to the surface of the door 2, where the first electrical contact means 21 of the door 2 is located. A second conductive area 42 of the seal 4 is attached to the surface of the door frame 3, where the second electrical contact means 31 of the door frame 3 is located. First and second electrical contact means 21, 31 and first and second conductive areas 41, 42 are indicated as dashed squares inside the area covered by the seal 4. The back line C2 denotes the electrical connection between the first and the second conductive areas 41 , 42 of the seal 4. The electrical connection between the first and second electrical contact means 21, 31 is shown as dashed line C2. The electrical connection CI and C2 establish a closed electrical circuit C indicating the successful sealing of the door 2. The electrical connection C2 (so-called open electrical circuit in case of non-attached seals) can be established by a wire extending from the first electrical connection means 21 arranged at the surface of the door 2 through the door 2, the door hinge and the door frame 3 to the second electrical contact means 31 arranged at the surface of the door frame 3 at a position close to the position of the first electrical contact means 21 of the door 2. The electrical connection CI is only one example of possible electrical connections CI. People skilled in the art are able to choose other kinds of electrical connections between first and second electrical contact means within the scope of this invention. Here the door frame 3 is part of the wall of the transport vehicle 7. The transport vehicle 7 is only indicated schematically. The transport vehicle 7 could be e.g. a truck, a car, a train wagon, a ship, a container for container trucks, an aircraft such as an airplane or a helicopter.

Fig.2 shows two embodiments of a seal 4 attached to the door 2 and the door frame 3. In both cases the seal 4 comprises a first conductive area in an electrical contact to the first electrical contact means 21 of the door 2 and further comprises a second conductive area 42 in an electrical contact to the second electrical contact means 31 of the door frame 3. The electrical connection CI between the first and second electrical contact means 21, 31 via door 2 and door frame 3 (also denoted as open electrical circuit CI in case of no attached seal 4) and the electrical connection C2 between first and second conductive area 41, 42 of the seal 4 establish a closed electrical circuit C together with first and second electrical contact means 21, 31 contacted to the first and second conductive areas 41, 42. In order to provide a seal fixed to the door and the door frame, the geometrical shape of first and second electrical contact means 21, 31 and the first and second conductive areas 41, 42 might be adapted to fix the seal 4 to door 2 and door frame 3 in a snug fit manner, as shown as an example in figure 2a. Here the first and second conductive areas 41, 42 of the seal 4 are arranged as cylindrical parts fitting into the first and second electrical contact means 21, 31 arranged as adapted cylindrical holes in door and door frame, where the open electrical circuit CI comprises spring mounted contact points at the bottom of the holes as part of the first and second electrical contact means 21, 31 providing a good electrical contact to the cylindrical conductive areas 41, 42 of the seal 4, which could be for example metal pins or pins covered by a metal layer. In other embodiments the shape of the first and second electrical contact means and conductive areas may deviate from a cylindrical shape. As an example the shape of the cross section of the hole might be the rectangular, oval, hexagonal or any other shape. Also the depth of the holes or recesses might be different as well as the dimensions of the protruding first and second conductive areas 41, 42. The first and second electrical contact means might be arranged as plug-ins or recesses for first and second conductive areas shaped as corresponding sockets or protrusions. Alternatively the first and second electrical contact means 21, 31 and/or the first and second conductive areas 41, 42 might be arranged at the surface of seal, door and door frame and being magnetic, as shown as an example in figure 2b. In this case, the shapes of first and second electrical contact means and conductive areas do not have a shape exactly adapted to each other as long as the magnetic force between the contact points is strong enough to fix the seal 4 to door 2 and door frame 3. People skilled in the art may choose other suitable shapes or properties of first and second electrical contact means and conductive areas to obtain a seal fixed to the door and the door frame within the scope of this invention. The seal 4 comprises a body, where the first and second conductive areas are connected via an electrical connection C2 either through the body or via a conductive path on top of the surface of the seal 4. The seal 4 (or the door 2 or the door frame 3) may further comprise a lighting unit 43 (e.g. a LED) to indicate the activation A of the indication means 6, which has to be arranged within the closed electrical circuit C established by contacted circuits CI and C2. The indication means can be arranged (a) within the electrical circuit CI within door and door frame or (b) within the electrical circuit C2 of the seal 4. People skilled in the art may choose the appropriate location of the indication means 6 according to the particular application within the scope of this invention. The indication means 6 may comprise a sending means 61 to send-out a warning signal 62 in case of a broken electrical circuit C, which was closed formally. A power source 8 might be arranged within the electrical circuit C to operate the indication means 6 and the sending means 61 , either inside the seal or in the electrical circuit CI . The indication means 6 may provide a machine-readable code M in order to identify the sealed door 2. Alternatively such a machine-readable code M might be attached to the surface of the seal 4, e.g. as a barcode label. The arrow S indicates the direction of attaching the seal to door and door frame. Fig. 3 shows a portable logging device 5, e.g. shape as a hand-held scanner, to record the sealing of doors 2. The portable logging device 5 comprises a data insert unit 51 to insert a particular type of the transport vehicles 7 (here displayed as "ABC..." in the display unit 54) and to insert the executed attachment of a seal 4 as well as a data unit 52 to store the inserted data. For example, the data unit 52 could be a storage chip or a storage card permanently or reversible mounted to the portable device 5. The data insert unit 51 could be any suitable array of buttons or keys suitable to insert the required data. Here the data insert unit 51 is a small key board. The portable logging device 5 further comprises a display unit 54 to display the location of the doors 2 to be sealed with seals 4. As an example, an aircraft is displayed as the transport vehicle 7, where the two doors (in this particular example) are indicated with bold arrows LI , L2 to support the operator executing the sealing procedure, where the seals 4 have to be attached. After attaching a seal 4 to a door 2 and the corresponding door frame 3 at a location LI, the portable logging device 5 reads R the machine-readable code of the indication means 6 of the particular closed electrical circuit C with a reading unit 53 and stores the machine-readable code in the data unit 52. The code of the indication means 6 is now correlated to the particular door (location LI as an example), where the seal is attached. The correlated data of seal and location improves the inspection procedure in case of reopened doors and also improves the logging of the sealing procedure and simplifies the archiving of the data of each sealing procedure. The portable logging device 5 further comprises a data connection unit 55 to transfer the data (identification code of the seal correlated to a certain location of the door, type of the transport vehicle and optional administrative data such as attaching time etc.) to a computer system 11. The data connection further allows to up-date the data stored in the data unit 52. The data connection 55 is preferably a wireless data connection, where the data are received by a receiving station 9 also able to receive a warning signal 62 in case of a broken electrical circuit C and transmitted to the computer system 11 by another data connection, e.g. a data cable. Alternatively, the data connection could be a data port unit able to be inserted in a corresponding plug-in unit to connect the portable logging device 5 to the computer system 11. In other embodiments, it could be possible to active A the seal 4 with the portable logging device 5 sending out an activation signal A as indicated by the dashed line. The same or other receiving stations 9 as used for establishing the data connection to the portable logging device 5 can be used to receive the warning signal 62 from the seal 4 in case of a re-opened door 2. Fig.4 shows an embodiment of a sealing system 1 according to the present invention. Here, the schematically indicated transport vehicle 7 comprises two doors 2, both doors 2 are sealed with attached seals 4. The portable logging device 5 is used to read R the machine readable code provided by the indication means (not shown here in detail) after activation A of the indication means in order to start controlling the status of the door 2. The transport vehicle 7 is located in a clearance area 10 as part of a logistic terminal or logistic center, e.g. an airport, a station etc. further comprising four receiving stations 9 suitable to receive the sealing data transmitted from the portable device 5 in order to record the sealing procedure and to receive a warning signal 62 in case of a damaged or detached seal 4 and subsequently broken closed electrical circuit from any location inside the clearance area 10. The sealing data and/or the warning signal 62 are transmitted from the receiving station 9 to the connected computer system 11 , where the sealing data are archived. The sealing data can be re-checked in case of doubts for any performed sealing procedure. The check proves the accurate execution of the sealing procedure without the necessity to repeat the sealing procedure manually, which saves clearance time. In case of a received warning signal 62, the computer system 11 provides an alarm signal 63 via an alarm means 12 (e.g. loudspeakers etc.) at least inside the clearance area 10, preferably also to security operators located outside the clearance area 10. Fig.5 shows three examples of transport vehicles 7, where the sealing system, the seal 4 and the portable logging device can be applied to, e.g. an airplane, a truck or a train wagon. The application of the seal 4, the portable device, the sealing system and the sealing method to other transport vehicles 7 with doors 2 and door frames 3 is also covered by the present invention.

While the invention has been illustrated and described in details in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed

embodiments.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference sign in the claims should not be construed as limiting the scope.

LIST OF REFERENCE SIGNS

1 sealing system according to the present invention

2 door of a transport vehicle

21 first electrical contact means

3 door frame

31 second electrical contact means

4 seal

41 first conductive area of the seal

42 second conductive area of the seal

43 lighting unit

5 portable logging device

51 data insert unit

52 data unit to store the inserted data

53 reading unit

54 display unit

55 data connection unit

6 indication means

61 sending means

62 warning signal

63 alarm signal

7 transport vehicle

8 power supply, e.g. battery

9 receiving station

10 clearance area

11 computer system

12 alarm means

A activating the indication means

C closed electrical circuit

CI open electrical circuit / conductive connection between first and second electrical contact means via door and door frame

C2 electrically connection between first and second conductive area of the seal via the seal

LI, L2 displayed location of doors

M machine-readable code

R reading of the machine-readable code