Abstract:
A laminated product having a thickness that can be adjusted by chipping, and including alternating sheets and layers of an adhesive material in a stack, each sheet possessing an intrinsic resistance to tearing and each layer of adhesive material connecting adjacent sheets in the stack with a linking force which is weaker than the resistance of the sheets to tearing, enabling each sheet to be detached from the stack without tearing. The product includes a housing which is disposed inside the thickness of the stack, and an electronic identification element which is disposed in the housing.

Description:
FIELD OF THE INVENTION 
     The invention relates in general to laminated products and the monitoring of these products. 
     More precisely, according to a first aspect, the invention relates to a laminated product whose thickness can be adjusted by exfoliation, this product having an alternating stack of sheets and layers of an adhesive material, each sheet having an intrinsic resistance to tearing, and each layer of adhesive material connecting two adjacent sheets of the stack to one another by a bonding force which is less than the resistance of the sheets to tearing, from which it results that each sheet can be detached from the stack without being torn. 
     BACKGROUND 
     Products of this type are known in prior art and are used in particular as adjustment shims for mechanical assemblies. These assemblies generally have extensive play at certain points, resulting from the combination of manufacturing tolerances. This play is compensated for by insertion of shims. 
     The thickness of these shims is adjusted by removing the upper or lower sheets one by one until the desired thickness is reached. 
     These shims are used in particular in industries in which the complete traceability of all the parts is required for reasons of safety or quality assessment. This is the case, for example, in aeronautics. Each part constituting an aircraft is numbered, and a quality assessment file is associated with it containing the manufacturing plans or at least their references, the materials certificates, the references of the manufacturing specifications, etc. 
     The serial numbers of the peelable shims are generally marked in indelible ink by a stamp on the upper side of the shim at the time of manufacturing. 
     This technique has a number of defects. 
     The upper sheets of the shim bearing the serial number are removed during the operation of adjustment of the thickness of the shim. Once this operation is done, the shim can no longer be identified. It can be lost or interchanged by mistake with another one between the time its thickness is adjusted and the time it is positioned. 
     Furthermore, the marking is difficult to read on certain types of shims such as, for example, shims made of composite material, which have a surface which is unsuitable for stamping, smooth or hatched depending on the materials. 
     Finally, since the shims are generally small in size, the volume of information that can be marked on the shim is very small. It is generally limited to the serial number of the shim. 
     SUMMARY OF THE INVENTION 
     In this context, the present invention aims to palliate the defects mentioned above. 
     For this purpose, the product of the invention comprises a housing in the thickness of a stack, and an electronic identification component arranged in the housing. 
     In a possible embodiment of the invention, the electronic component has a memory for storage of identification information identifying or characterizing the product, and a transmission device that can be queried at a distance and is capable of transmitting the identification information stored in the memory. 
     Advantageously, the identification information stored in the memory includes at least the serial number of the product. 
     Preferably, the memory has a large storage capacity, sufficient for storing at least a major part of the identification information such as: identification of the manufacturer of the product, type of product, reference of the order, identification of the client, identification of the material constituting the product and reference of the material certificate, reference of the standard applicable to the manufacturing of the product, reference of the technical specifications of the product, reference of the certificate of compliance with standards, manufacturing date, reference of the delivery voucher, delivery date. 
     For example, the memory has a storage capacity of at least 512 bits. 
     Advantageously, certain identification information is stored in the memory in coded form. 
     Preferably, the transmission device is capable of receiving identification information at a distance and of writing it in the memory. 
     For example, the electronic component can be locked in terms of writing. 
     Advantageously, the electronic component has the general shape of a cylinder whose exterior diameter is less than 4 mm. 
     Preferably, the electronic component has some means for measurement of temperature and/or of pressure and/or of vibrations and/or of irradiation, the transmission device being capable of transmitting the results of the measurements made by the means. 
     For example, the electronic identification component has a very small thickness, the memory having sufficient storage capacity for storing the essential identification information, the other information being stored on an external support. 
     Advantageously, the electronic identification component has a thickness less than 200 μm. 
     Preferably, the electronic identification component has a cross section less than 2.5 mm 2 . 
     For example, the memory has a capacity greater than 64 bits. 
     Advantageously, the electronic component can be used in read mode alone. 
     Preferably, the housing is delimited by an interior wall, with a hardening filling material filling the housing around the electronic component and connecting it to the interior wall. 
     For example, the filling material is a resin, for example, an epoxy, phenolic, vinyl ester or polyvinyl resin. 
     Advantageously, the sheets consist of a metallic or composite material. 
     Preferably, the sheets all extend parallel to a plane of reference, the housing also extending parallel to the plane of reference. 
     According to a second aspect, the invention relates to a device for identification and monitoring of laminated products as described above, and comprising a reading unit which communicates with the transmission device of the electronic component, the reading unit being capable of consulting the identification information stored in the memory. 
     For example, the reading unit is portable and communicates at a distance, without a wire link, with the electronic component. 
     Advantageously, the device has an information processing unit for management of the identification information, the reading unit being capable of transmitting the information read in the memory to the information processing unit. 
     Preferably, the reading unit is capable of transmitting to the electronic component the identification information managed by the information processing unit, for writing in the memory. 
     For example, the information processing unit carries out the coding and decoding of certain identification information stored in coded form in the memory. 
     Advantageously, the coding and decoding of the identification information are done using tables putting in correspondence the information to be coded and an alphanumeric code to be stored in the memory. 
     Finally, according to a third aspect, the invention relates to the application of a laminated product as described above to a peelable adjustment shim for mechanical assemblies. 
    
    
     
       BRIEF DESCRIPTION OF DRAWING FIGURES 
       Other characteristics and advantages of the invention will emerge clearly from the description given for it below on an indicative and non-limiting basis, in reference to the appended figures among which: 
         FIG. 1  is a perspective view of a laminated product according to a first embodiment of the invention, 
         FIG. 2  is a view in cross section of the electronic identification component according to arrows II of  FIG. 1 , 
         FIGS. 3A and 3B  are simplified diagrams of a device for monitoring of the products of the invention, respectively showing the reading unit communicating with the information processing unit, and the reading unit communicating with the electronic identification component, and 
         FIG. 4  is a view equivalent to  FIG. 1 , in the case of a second embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  represents a laminated product whose thickness can be adjusted by exfoliation, the thickness being the vertical dimension of the product as represented in  FIG. 1 . 
     This product has alternating stack  10  of sheets  11  and layers  12  of an adhesive material. The product is prepared using thin sheets  11  whose thickness generally varies between 0.1 and 0.01 mm. These sheets  11  are coated with an extremely thin film of adhesive material, on the order of 0.002 mm, and are stacked. Stacked sheets  11  then undergo a treatment consisting of applying a very high pressure to them while subjecting them to prolonged heating cycles. The thickness of layers  12  of adhesive material is even smaller after treatment, this thickness becoming barely measurable, 
     Each sheet  11  has an intrinsic resistance to tearing, and each layer of adhesive material  12  connects two adjacent sheets  11  of stack  10  to one another by a bonding force which is less than the resistance of sheets  11  to tearing. Consequently, each sheet  11  can be detached from stack  10  without being torn. A cutter is generally used for detaching sheets  11 . 
     According to the invention, the product has housing  20  provided within the thickness of stack  10 , and electronic identification component  30  arranged in housing  20 . 
     Electronic component  30 , ordinarily called a chip, has memory  31  for storage of identification information identifying or characterizing the product, and transmission device  32  that can be queried at a distance and is capable of transmitting the identification information stored in memory  31 . 
     This identification information includes at least the serial number of the product. 
     According to a first embodiment of the invention, illustrated in FIGS.  1  to  3 A/ 3 B, memory  31  has a large storage capacity, sufficient for storing at least a major part of the following information: identification of the manufacturer of the product, type of product, serial number of the product, reference of the order, identification of the client, identification of the material constituting the product and reference of the material certificate, reference of the standard applicable to the manufacturing of the product, reference of the technical specifications of the product, reference of the certificate of compliance with standards, manufacturing date, reference of the delivery voucher, delivery date. 
     Memory  31  has a storage capacity of at least 512 bits, and preferably 1024 bits, allowing 108 alphanumeric characters to be stored. 
     This capacity is sufficient to store all of the information listed above. Certain identification information is stored in memory  31  in coded form as will be seen further on. 
     This list is not limiting, and other information can also be stored in memory  31 , within the limit of its storage capacity. This other information can also replace certain information listed above. 
     Transmission device  32  is furthermore capable of receiving identification information at a distance and of transmitting it to memory  31  that stores it. 
     Electronic component  30  can be locked in terms of writing. 
     Electronic component  30  is represented in  FIG. 2 . It has the general shape of a cylinder, with an exterior diameter less than 4 mm. This cylinder can typically have a length of 13.3 mm and an exterior diameter of 3.15 mm. 
     Transmission device  32  has copper coil  321  functioning as an antenna, which is electrically connected to memory  31 . 
     Memory  31  and transmission device  32  are arranged inside sealed cylindrical glass envelope  33 . Antenna  321  of transmission device  32  occupies an axial end of envelope  33 . 
     Electronic component  30  typically functions at a frequency of 125 kHz. 
     As can be seen in  FIG. 1 , sheets  11  all extend parallel to a plane of reference P, represented to be horizontal in  FIG. 1 . Housing  20  preferably extends parallel to the plane of reference P, occupying the smallest possible thickness of the product. 
     This housing  20  is cylindrical and blind and opens through open end  23  onto a lateral surface of the product. It can be produced very simply, for example, using a drilling machine. 
     It has an interior diameter slightly greater than the exterior diameter of envelope  33  of electronic component  30 . 
     Electronic component  30  is arranged in housing  20 , the axis of symmetry of electronic component  30  being parallel to the axis of symmetry of housing  20 . Antenna  321  of transmission device  32  is arranged on the side of open end  23  of housing  20 . 
     Housing  20  is delimited by interior wall  21 , a hard filling material  22  filling housing  20  around electronic component  30  and connecting it to interior wall  21 . 
     This filling material  22  is typically resin, for example, of the epoxy, phenolic, vinyl ester or polyvinyl type. 
     The invention also relates to a device for identification and monitoring of laminated products provided with an electronic identification component such as that described above. 
     Device  40  has information processing unit  41  for management of the identification information, and reading unit  42  communicating with information processing unit  41  and with transmission device  32  of electronic component  30 . 
     Reading unit  42  is capable of consulting the identification information stored in memory  31  and of transmitting it to information processing unit  41 . To do this, it queries electronic device  30  by sending a signal to transmission device  32 , this device transmitting the identification information stored in memory  31  to reading unit  42 . 
     Reading unit  42  is also capable of transmitting to electronic component  30  the identification information managed by information processing unit  41 , for writing in memory  31 , by the intermediary of transmission device  32 . 
     Information processing unit  41  is a microcomputer equipped with database management software. 
     This software is programmed in such a way as to present the user of the device with predetermined data entry forms containing fields corresponding to the identification information stored in memory  31 . 
     The information present in the form of an alphanumeric code is stored in this form in memory  31 . This information is typically: serial number of the product, reference of the order, reference of the material certificate, reference of the technical specifications of the product, reference of the certificate of compliance with standards, manufacturing date, reference of the delivery voucher, delivery date. 
     Other information is stored in memory  31  in coded form, because it would occupy too much room in memory  31  in its usual form or because it is present in unsuitable forms. This information is typically: identification of the manufacturer of the product, type of product, identification of the client, identification of the material constituting the product and reference of the standard applicable to the manufacturing of the product. 
     Information processing unit  41  carries out the coding and decoding of the identification information stored in coded form in memory  31 . 
     The coding and decoding are done using tables included in the software, putting in correspondence the information to be coded and an alphanumeric code to be stored in the memory. 
     Reading unit  42  is portable, lightweight, small in size, and can be transported easily by the user. 
     This unit has a buffer memory for storage of the identification information, display screen  421 , and control device  422 . 
     The buffer memory makes it possible to temporarily store the identification information read in memory  31  of electronic component  30 , or the identification information to be written in memory  31  of electronic component  30 . 
     Screen  421  makes it possible to display certain identification information and to display parameters concerning the functioning of reading unit  42 . 
     Control device  422  is preferably a keyboard and makes it possible to trigger the reading of the identification information in memory  31  of electronic component  30 , the writing of this information in memory  31  and the locking in terms of writing of electronic component  30 . 
     Reading unit  42  communicates at a distance, without a wire link, with electronic component  30 , as shown by  FIG. 3B . 
     The information is transmitted between reading unit  42  and electronic component  30  by waves or by optical means. For this purpose, reading unit  42  has transmission means cooperating with transmission device  32  of electronic component  30 . 
     In an execution variant, reading unit  42  and electronic component  30  can communicate by optical fibers. 
     The range of the transmission is short, which limits interferences with other electronic systems in the vicinity. Reading unit  42  must be arranged a distance of one to ten centimeters from electronic component  30  during communications. 
     Reading unit  42  communicates with information processing unit  41 , for example, by removable wire link. For this purpose, identification device  40  has cable  43  of type RS232, reading unit  42  and information processing unit  41  having respective ports of type RS232 to which the ends of cable  43  are connected by suitable plugs. Reading unit  42  can also communicate with information processing unit  41  by optical link or any other suitable type of link. 
     This wire link ensures the transfer of the identification information between the buffer memory of reading unit  42  and information processing unit  41 . 
     The “marking” procedure for identification of a laminated product is the following. 
     1/ Introduction of electronic component  30  into housing  20  of the product. 
     2/ Filling of housing  20  with filling material  22 , hardening. 
     3/ Introduction by a user of the identification information into the database of information processing unit  41 , by entering the information in the different headings of the form provided for this purpose. 
     4/ Connection of reading unit  42  to information processing unit  41 , by connection of connecting cable  43  in the corresponding ports of these units. 
     5/ Coding of certain identification information by information processing unit  41 , and transfer of all the identification information into the buffer memory of reading unit  42 . 
     6/ Disconnection of connecting cable  43 . 
     7/ Manual transfer by the user of reading unit  42  to the vicinity of the product. 
     8/ Transfer of the identification information from the buffer memory of reading unit  42  into electronic component  30  and writing of the information in memory  31 , as ordered by the user. 
     9/ Locking in terms of writing of electronic component  30 , as ordered by the user. 
     The procedure for reading of the identification information is the following. 
     1/ Manual transfer by the user of reading unit  42  to the vicinity of the product. 
     2/ Reading of the identification information in memory  31  of electronic component  30 , as ordered by the user, and transfer of the information into the buffer memory of reading unit  42 . 
     3/ Manual transfer by the user of reading unit  42  to the vicinity of information processing unit  41 . 
     4/ Connection of reading unit  42  to information processing unit  41 , by connection of connecting cable  43  in the corresponding ports of these units. 5/ Transfer of the identification information from the buffer memory of reading unit  42  into information processing unit  41 , as ordered by the user from information processing unit  41 . 
     6/ Decoding of the identification information by information processing unit  41 . 
     7/ Display of the identification information by the user using the forms provided in the database. 
     The product can be manufactured with sheets  11  made of metallic or composite material. In the case in which sheets  11  are metallic, particular precautions must be taken in order to guarantee the quality of the communication between electronic component  30  and reading unit  42 . 
     Antenna  321  of transmission device  32  of electronic component  30  in this case is arranged in the immediate vicinity of open end  23  of housing  20 . Furthermore, the interior diameter of housing  20  is chosen to be sufficiently large relative to the exterior diameter of envelope  33  of electronic component  30 . A minimum separation, for example, 0.5 mm, is maintained between electronic component  30  and interior wall  21  of housing  20 . 
     In an execution variant, electronic component  30  can have some means for measurement of the ambient temperature, of pressure exerted on the product, of vibrations or of irradiation. The measurement results are transmitted by transmission device  32  to reading unit  42  which in turn transmits them to information processing unit  41 . 
     A second embodiment of the invention is represented in  FIG. 4 . Only the differences with respect to the first embodiment will be described below, the elements which are identical or which have the same function in both embodiments keeping the same references. 
     In the second embodiment, electronic identification component  30  has a very small thickness, memory  31  having a limited storage capacity relative to the first embodiment but sufficient to store the essential identification information, the other information being stored on an external support. 
     Thus, electronic identification component  30  has a thickness less than 200 μm and preferably less than 150 μm. 
     Electronic identification component  30  is present in the form of a rectangular parallelepiped, with a cross section less than 2.5 mm 2  in a plane perpendicular to the thickness. This cross section is typically a square section, 1.3 mm on a side. 
     Electronic identification component  30  has a silicon chip whose size corresponds approximately to that of component  30 , carrying an antenna on one of its two large sides constituting transmission device  32 . Antenna  32  consists of a metallic micro-wire spirally wound on the large side of the chip, in such a way that this antenna has a thickness of only 20 μm. The pitch of the winding is approximately 10 μm. A very thin layer of polyamide protects the antenna from mechanical impacts. Component  30  functions at a frequency of approximately 15.56 MHz. 
     Memory  31  has a capacity greater than or equal to 64 bits. It generally only contains the serial number of the product. The other information for identification of the product can be consulted in the quality assessment file associated with the product or is stored in digital form in an external memory, for example, a CD-ROM. 
     Knowledge of the serial number of the product enables one to find the file or access the information stored in the external memory. 
     Electronic component  30  can be used in reading alone. The serial number of the product is written in memory  31  using a special known device, before electronic component  30  is arranged and secured in housing  20 . 
     Housing  20  in which electronic component  30  is arranged has a shape corresponding to the shape of this component, that is to say parallelipipedic. 
     Housing  20  is hollowed on an upper or lower side of the product. It extends parallel to plane P in such a way that the product is only hollowed over a very small thickness corresponding to the thickness of electronic component  30 . 
     As in the first embodiment, electronic component  30  is secured in housing  20  by epoxy resin. 
     The side of electronic component  30  carrying antenna  32  is arranged on the open side of housing  20 . 
     The identification information stored in memory  31  is read using known reading unit  42 , present in the form of a pen. 
     This pen contains a buffer memory in which the serial number read in memory  31  of the electronic component is stored. 
     This number is displayed directly on a display component of the pen. In an execution variant, this number is displayed using a known reader to which the pen is connected. 
     In an execution variant which is not represented, housing  20  is not hollowed in the upper surface or in the lower surface of the product but rather in a lateral surface. 
     It is therefore understood that the invention makes it possible to identify laminated products in a reliable and lasting manner without risk of loss of information when the upper or lower layers of the product are peeled in order to adjust its thickness. 
     In the first embodiment of the invention, a large number of information items can be stored in the electronic component and therefore can be physically associated with the laminated product continually, which was not previously possible. 
     This information remains continually readable and accessible even after the product has been inserted in a mechanical assembly. 
     On the other hand, this embodiment can only be used for products with a sufficient thickness. 
     The second embodiment of the invention is suitable rather for laminated products of small thickness because of the extreme thinness of the electronic component. On the other hand, a smaller number of identification information items can be stored in memory. 
     Of course, the execution examples mentioned here are not limiting, and it is indeed understood that it is possible to choose the type and size of the identification component as a function of the thickness of the laminated product so as to obtain the best memory capacity/space requirement compromise. In any case, laminated products equipped with identification components combining a large storage capacity and a very small thickness are also included in the scope covered by the invention. 
     Furthermore, the identification means of the invention is inviolable and unfalsifiable. The electronic components cannot be extracted from the housings when the filling material has been put in place and set. To extract the identification means, it would be necessary to destroy the shim or the electronic component itself. In addition, the electronic components can be locked in terms of writing or can only be used in reading alone. 
     Frauds concerning the origin of laminated products are therefore made much more difficult or even impossible in the case of the first embodiment since all the data allowing identification of the product are continually accessible and are unfalsifiable. 
     It should be noted that the laminated products described above are quite suitable for being used as peelable shims in order to take up the play in mechanical assemblies, particularly in the aeronautics industry in which all the parts are the object of very thorough monitoring and quality assessment.