Abstract:
A keyless access system is provided for a truck including a tractor area and a cargo area provided with at least an access door. This system includes a main control unit located in the tractor area and adapted to interact with a customer identification device to selectively operate a control access arrangement which allows or prevents access to a driver cabin of the truck, a secondary control unit located in or near the cargo area and adapted to interact with the same customer identification device and to selectively operate an actuator which locks or unlocks the access door, and a bidirectional telecommunication arrangement between the main and secondary units.

Description:
BACKGROUND AND SUMMARY 
     This invention concerns a keyless access system for a truck including, amongst others, a cargo area. This invention also concerns a truck equipped with such a system, a control unit to be used in such a system and a method to be implemented with such a system. 
     Keyless systems have been known to allow an easy access to a personal vehicle because the user does not have to open a door with a key in so far as a customer identification device or CID, which is often in the form of a remote controller or an electronic card or tag, is recognized by the system when the user comes close to a door or a vehicle. 
     An active electronic keyless access system is a system where a user actuates his remote controller, e.g. by pressing a button, to unlock a door of the vehicle. A passive keyless access system is a system where the user has a customer identification device which can exchange information with an onboard control unit without being manually actuated by the user. This invention applies to an active keyless access system and to a passive keyless access system. 
     As disclosed in U.S. Pat. No. 5,532,521, keyless systems have been used to control access to a cargo zone of a truck, which facilitates the work of the driver. When the driver wants to access the cargo zone, he must actuate a transmitter to generate a signal processed to open a rear access door. When exiting the storage area, the driver must tap a switch to close and lock the door. With this system, the driver must remember to open the rear door of the truck before leaving his seat and must not forget to close the door when re-entering the cabin. This is tedious, especially for vehicles which are used to deliver goods in several locations, like stores, in a city. 
     On the other hand, keyless access systems have been designed in order to control access and, in some instances as in FR-A-2 815 149, control an auxiliary equipment like an audio device. Such systems are not adapted for trucks. No known systems take into account the fact that the driver of a truck might wish to exit the cabin and to go to a rear door in order to access a cargo area, without having to remember to actuate a transmitter before leaving the cabin or a switch before leaving the cargo area. 
     The invention aims at providing a keyless access system which facilitates the work of a driver by providing an easy, automatic and secure access to the cargo area of a truck. 
     To this purpose, the invention concerns a keyless access system for a truck including a tractor area and a cargo area provided with at least an access door, this system comprising:
         a main control unit located in the tractor area and adapted to interact with a customer identification device to selectively operate access means which allow or prevent access to a driver cabin of the vehicle,   a secondary control unit located in or near the cargo area and adapted to interact with the same customer identification device and to selectively operate an actuator which locks or unlocks the access door, and   bi-directional telecommunication means between the main unit and the secondary unit.       

     Thanks to the invention, the secondary unit can be used to lock or unlock the access door to the cargo area depending on the fact that a person standing near this door and outside the truck has or not a customer identification device, hereafter called “CID”, known by the system as valid to access the cargo area. 
     According to further aspects of the invention, this system might incorporate one or several of the following features:
         The communication means between the main and secondary units are wireless.   The secondary unit is adapted to interact with a CID in order to collect data from this device and to send some information representative of these data to the main unit which is adapted to determine, on the basis of the information received from the secondary unit, if the access door is to be opened for this CID and, if such is the case, to send to the secondary unit, a clearance signal for this door.   Each main or secondary unit is connected to at least an activation switch, at least a lock actuator, at least an antenna adapted to send an activation signal towards a CID and/or to receive a response signal from the CID. Preferably, each unit is connected to a low frequency antenna adapted to emit the activation signal towards a CID and to a high frequency antenna adapted to receive a response signal from the CID.   The secondary control unit comprises means to collect data from a CID, means to send to the main access unit a signal representative of the data collected from the CID 1  means to receive from the main control unit a clearance signal and means to selectively operate, upon reception by the receiving means of a clearance signal from the main unit, an actuator which unlocks an access door to a cargo area of the vehicle.   Independent power supply means are provided, in or near the cargo area, for the secondary access unit.   The system is a passive keyless access system.       

     The invention also concerns a truck including a tractor area and a cargo area provided with at least an access door, this vehicle being provided with a keyless access control system as explained here-above. 
     According to a first embodiment, such a truck includes a tractor and a trailer, said main unit being mounted on the tractor whereas the secondary unit is mounted on the trailer. According to another embodiment, the truck comprises a cargo structure fixed on a frame belonging to a tractor, the main unit being mounted on the tractor, whereas the secondary unit is mounted on the structure. 
     The invention also concerns a control unit which can be used as a secondary unit in a system as mentioned here-above. This unit comprises means to collect data from a CID, means to send to a remotely located other control unit a signal representative of the data collected from the CID, means to receive from this other unit a clearance signal and means to selectively operate, upon reception by the receiving means of a clearance signal from the other unit, an actuator which unlocks an access door to a cargo area of a truck. 
     Finally, the invention concerns a method which can be implemented with the system mentioned here-above in order to control access to a cargo area of a truck. This method comprises at least the following steps of: 
     a)—detecting an unlock request of an access door to a cargo area of the vehicle, 
     b)—sending, from a first control unit located in or near the cargo area, a challenge signal towards a CID, 
     c)—receiving a signal corresponding to a response of the device, 
     d)—verifying, in a main control unit located in a tractor area of the vehicle, if the received signal corresponds to a valid identification code, 
     e)—if the received signal corresponds to a valid identification code, sending from the main unit to the first unit, a clearance signal, 
     f)—when a clearance signal is received in the first unit from the main unit, sending an actuation signal to an actuator which mechanically unlocks the access door. 
     According to a first approach, before step c), the response signal of the CID is received by the first unit and then a signal representative of this response signal is sent by the first unit to the main control unit. Alternatively, during step c), the response signal of the CID is received directly by the main control unit. 
     Advantageously, the signal transmission between the first and main units is wireless. According to an advantageous aspect of the invention, the challenge signal is a low frequency signal whereas the response signal is a high frequency signal and communication between the first and main units takes place in high frequency mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood on the basis of the following description which is given in correspondence with the annexed figures and as an illustrative example, without restricting the object of the invention. In the annexed figures: 
         FIG. 1  is a schematic side view of an truck incorporating the invention, 
         FIG. 2  is a top view of the vehicle of  FIG. 1 , the roof of the cabin being taken away, 
         FIG. 3  is a schematic view of a keyless access system used in the vehicle of  FIGS. 1 and 2 , 
         FIG. 4  is a block diagram of a method implemented with the system of  FIG. 3 , 
         FIG. 5  is a view similar to  FIG. 4  for another method implemented with the system of  FIG. 3 , and 
         FIG. 6  is a top view similar to  FIG. 2  for another truck incorporating the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The truck  1  represented on  FIGS. 1 and 2  includes a tractor  2  and a trailer  3  hooked onto the tractor and defining a cargo area  31  where goods to be transported can be stored. The tractor  2  defines a tractor area  21  where no goods are to be stored and which comprises, amongst others, the driver cabin  22  and the engine compartment  23  of tractor  2 . Cabin  22  is provided with two lateral doors  22 A and  22 B, door  22 A being located next to the driver&#39;s seat. 
     A keyless access system  100  is provided to control access to cabin  22  for a user U bearing a customer identification device or CID  200 . This CID is a small dimension electronic device, in the form of a tag or a, credit card or somewhat bigger, which is adapted to emit, when receiving a predetermined challenge signal, a response signal comprising an alphanumerical identification sequence which is specific to each CID. System  100  includes a main unit  101  which is fed with electrical power from the main electrical circuit  25  of tractor  2 . Unit  101  is connected to an activation switch  102 A located near the handle  22 C of driver&#39;s door  22 A, this switch being suitable to send to unit  101  a signal Si when handle  22 C is being touched by user U. Unit  101  is also connected to a low frequency antenna  103 A located on the driver&#39;s side of cabin  22 . When unit  101  receives signal S-i, unit  101  computes an alphanumerical sequence. Then, it sends to antenna  103 A an actuation signal S 2  corresponding to this sequence. Then, antenna  103 A sends a low frequency radio challenge signal S 3  which also corresponds to the computed sequence and which is supposed to be received by CID  200 . When it receives signal S 3 , CID  200  calculates a response signal S 4  which is sent as a high frequency radio signal and received by a high frequency antenna  104  connected to unit  101 . Signal S 4  received by antenna  104  is then verified by unit  101  and, if it is found that CID  200  permits access to cabin  22 , unit  101  sends a signal S 5  to an actuator  105 A which mechanically unlocks door  22 A. Unit  101  is also connected to an activation switch  102 B, a low frequency antenna  103 B and an actuator  105 B located on the passenger&#39;s door  22 B side and which are supposed to be used as explained here-above when a user wants to access cabin  22  by the passenger&#39;s side. 
     According to an optional aspect of the invention, unit  101  is associated with a passive go unit  110  which is capable of recognizing CID  200  when this device is within cabin  22  in order to allow starting of the engine and driving of tractor  2 , without having to use a mechanical key. Thanks to unit  101 , the driver can very easily access cabin  2 , as long as he has with him his CID  200 , either in his hand, or in his pocket or in a bag that he carries with him. 
     A secondary unit  151  is mounted in area  31 , close to the roof  33  of trailer  3 , in the vicinity of its back doors  32 A and  32 B. This secondary unit is connected to an activation switch  152 , a low frequency antenna  153 , a high frequency antenna  154  and an actuator  155 , in a way similar to the connection between items  101  to  105 . 
     Unit  151  is also connected to a battery  156  located in its vicinity and providing electrical current when necessary. 
     Unit  151  could be located elsewhere in or near area  31 , on trailer  3 , although one advantage of having unit  151  near access doors  32 A and  32 B is to be able to use short range communication means, like low frequency antenna  153 , between unit  151  and a CID  200 . 
     Bi-directional wireless communication means are respectively associated to unit  101 , as a first module  107 , and to unit  151 , as a second module  157 . For the sake of security, and in order to take into account that a trailer may be used with different tractors, unit  151  does not store tile confidential information relating to tile fact that one CID authorizes or not access to the cargo area  31  of a truck  1 . However, unit  151  is used to determine whether or not a user having a CID may access this area through doors  32 A and  32 B. The left part of  FIG. 4  corresponds to the steps of the access control method performed by unit  101  and its associated equipments when a user tries to access zone  31 , whereas the central part corresponds to the steps performed by unit  151  and the associated equipments and the right part corresponds to the steps performed by CID  200 . The last digit of their references corresponds to the chronological order of the method steps. The two first digits correspond to the parts by which they are performed ( 10  for unit  101  and its associated equipments in area  21 ,  15  for unit  151  and its associated equipments in area  31  and  20  for CID  200 ). 
     At the beginning, unit  101  is in sleeping mode as shown by step  1001 , whereas unit  151  is also in sleeping mode, as shown by step  1501 . When a user wants to open one of the back doors  32 A or  32 B 1  he touches a corresponding handle which is detected by actuation switch  152  in a first active step  1502  where a signal S′i goes from switch  152  to unit  151 . 
     Thereafter, in a further step  1503 , unit  151  computes a challenge signal in the form of a first code or CODE  1  and a random number N. This calculated signal is forwarded to antenna  153  in an activation signal S′ 2  and emitted as a challenge signal S′ 3  towards the CID  200  of the user. 
     Upon reception of signal S′ 3 , CID  200 , which knows CODE  1 , computes random number N in a first step  2004  and then calculates in a further step  2005  a response signal which is a function of the same number N and a code specific to CID  200 , noted as CODE  2 . Signal S′ 4  includes, amongst other, some identification data of CID  200 . 
     At the end of step  2005 , CID  200  sends a high frequency response signal S′ 4 , including CODE  2  and the computed number N, which is received by antenna  154  in a further step  1506 . 
     Actually, signal S′ 4  might be the same as or different from signal S 4 . 
     Response signal S′ 4  is then forwarded to unit  151  in a step  1507 . Then, in a further step  1508 , unit  151  uses module  157  to re-direct signal S′ 4 , as a signal Se, towards module  107  associated with unit  101 . According to an alternative embodiment of the invention, antenna  154  and module  157  can be the same component. In other words, a single antenna can be used to receive signal S′ 4  and send signal S 6 . 
     According to an alternative embodiment of the invention, signal S 6  re-directed by unit  151  towards unit  151  might be different from the signal S′ 4  received from CID  200 . In particular, signal S 6  may incorporate only a part of signal S′ 4 . 
     In all embodiments, number N, which is generated by unit  151  each time it is actuated, is incorporated within signal S 6 , so that unit  101  can extract the value of CODE  2  from signal S 6 . Therefore, unit  101  indirectly extracts CODE  2  from signal S′ 4 | as it does for signal S 4 . 
     Signal S 6  is received by module  107  in a step  1009 . It is then transferred to unit  101  in a further step  1010 . In step  1011 , unit  101  verifies if the information included in signal S 6  correspond to a CID which permits opening of doors  32 A and  32 B. 
     If this is not the case, the method stops and no activation of actuator  155  takes place. 
     If the information collected from unit  151  corresponds to an authorized CID, unit  101  activates, in a further step  1012 , module  107  to send a clearance signal S 7  towards module  157 . This signal is received by module  157  in step  1513  and forwarded, in step  1514 , to unit  151 . When it receives the clearance signal S 7 , unit  151  sends to actuator  155  an actuation signal S′ 5  so that actuator  155  mechanically unlocks doors  32 A and  32 B in step  1515 . 
     The low frequency used for transmitting signals S 3  and S′ 3  can be of 125 kHz, whereas the high frequency used for transmitting signals S 4 , S′ 4 , S 6  and S 7  is 433 MHz. Protocols like WIFI and Bluetooth can be used for the high frequency communication between modules  107  and  157 . The use of low frequency antennas  103 A,  103 B and  153  for signals S 3  and S′ 3  makes it possible to precisely tune the maximum distance, or reach, of the communication between unit  101  or  151  and CID  200 . Therefore, there exist few risks that a door is unlocked when the authorized user is still far away from this door. On the contrary, the high frequency signals S 4 , S′ 4 , S 6  and S 7  have a longer reach. 
     In the second embodiment of the invention represented on  FIG. 5 , the same steps as the ones mentioned here-above have the same references. Steps  1001 ,  1501 ,  1502 ,  1503 ,  2004  and  2005  are identical to the same steps on  FIG. 4 . In step  2005 , signal S′ 4  is sent directly to antenna  104  where it is received in step  1009 . It is then transferred to unit  101  in step  1010  and steps  1011 ,  1012  and  1513  to  1515  are identical to the equivalent steps in  FIG. 4 . 
     The invention is of particular interest for a truck provided with a trailer, as shown on  FIGS. 2 and 3 . However, as shown on  FIG. 6 , it can also be used for a truck  1  whose cabin  22  is supported on a frame  24  on which a cargo structure  34  is fixably mounted. Here again, a control access system including, amongst others, a main control unit  101  and a secondary control unit  151  can be used. 
     As shown on  FIG. 6 , the secondary control unit might be used to control access to a cargo area  31  via a side door  32 C of the truck. 
     The invention has been represented with the secondary unit  151  located in the cargo area  31  of a truck. In fact, this unit can also be located in the vicinity of this area, provided that it is close enough to the door or doors to be able to send, via its antenna  153 , signal S′ 3  to CID  200  and to receive, via its antenna  154 , signal S 4  from CID  200 . 
     In the first embodiment, the fact that communication between modules  107  and  157  is wireless is of particular interest since no specific precaution must be taken when the trailer  3  is hooked onto a tractor  2  or when it is separated from this tractor. 
     One can consider a connection between the main and secondary units via wires, in particular for a truck with a rigid structure as represented on  FIG. 6 . 
     The invention has been described when used with a passive keyless access system. However, it may also be used with an active keyless access system. In such a case, activation switches  102 A 1   102 B and  152  do not belong to system  100 . 
     List Of References
       1  truck     2  tractor     21  tractor area     22  driver cabin     22 A driver door     22 B passenger door     22 C handle     23  engine compartment     24  frame     25  electrical circuit     3  trailer     31  cargo area     32 A back door     32 B back door     32 C side door     33  roof     34  cargo structure     100  system     101  main control unit     102 A activation switch     102 B activation switch     103 A low frequency antenna     103 B low frequency antenna     104  high frequency antenna     105 A actuator     105 B actuator     107  communication module     110  passive go unit     151  secondary control unit     152  activation switch     153  low frequency antenna     154  low frequency antenna     155  actuator     156  battery  157  communication module     200  customer identification device or CID     1001  step in tractor area  21       1009  step in tractor area  21       1010  step in tractor area  21       1011  step in tractor area  21       1012  step in tractor area  21       1501  step in or near cargo area  31       1502  step in or near cargo area  31       1503  step in or near cargo area  31       1506  step in or near cargo area  31       1507  step in or near cargo area  31       1508  step in or near cargo area  31       1513  step in or near cargo area  31       1514  step in or near cargo area  31       2004  step in CID  200       2005  step in CID  200     U user   Si signal   S′i signal   S 2  signal   S′ 2  signal   S 3  challenge signal   S′ 3  challenge signal   S 4  response signal   S  4  response signal   S 5  actuation signal   S′s actuation signal   S 6  redirected signal   S 7  clearance signal