Abstract:
A method and a machine for assembling a blister sheet and a linerboard, the board optionally having a flap. The blister sheet, the linerboard and the optional flap are flat stacked on top of one another; and the layers are subsequently heat sealed, preferably by means of thermal conduction or induction between a counter electrode and an electrode, continuously and in respective closed circuits, in order to produce cases for packaging such items as medicaments, electronic components, small tools, perfume samples or any other product which is to be enclosed in at least one bubble of the blister sheet.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a method of assembly between:
         a blister sheet having two plane main faces and comprising at least one product containment blister projecting on a first of said main faces, and   a linerboard having two plane main faces and comprising at least one hole for the passage of said blister,       

   the blister sheet and the linerboard being capable of occupying a defined relative position, in which a first of said main faces of the linerboard is laid against the first main face of the blister sheet, around the blister, and at least one of the first main faces being thermoadhesive or being made thermoadhesive, 
   said method comprising the succession of steps involving: 
   a) placing the blister sheet and the linerboard in said defined relative position, 
   b) applying to the blister sheet and to the linerboard, which occupy said defined relative position, a pressure for the mutual clamping of their first main faces and a treatment capable of making adhesive said first main face which is thermoadhesive or is made thermoadhesive, for the time necessary for bringing about a mutual thermoadhesion of said first main faces, 
   c) causing the application of said pressure and said treatment to cease. 
   Such a method is used, for example, in the pharmaceutical industry, in order to assemble a blister sheet generally comprising a plurality of blisters containing a respective dose of a drug, for example in the form of a tablet or of a capsule, together with a linerboard carrying particulars identifying the drug and, for example, particulars relating to its dosage or particulars making it easier to adhere to this dosage. Said method may also have applications in very different technical fields, such as the packaging of perfume samples, of electronic components or of small tools, these examples in no way being limiting. 
   In the present prior art, this method is employed:
         either manually, that is to say, more specifically, by handlers who superpose the blister sheet and the linerboard in said defined relative position by hand, if appropriate turn down flat onto the second of the main faces of the blister sheet a flap initially placed in the extension of the linerboard, in order to carry out step a, then manually offer the assembly thus formed between the plates of a thermoadhesion press, manually command the application of pressing, generally for a predetermined time, thereby carrying out steps b and c, and then manually recover the assembly thus assembled after the opening of the press,   or automatically, corresponding, in fact, to an automation of the steps of the manual method which has just been described, especially with regard to the offer to the thermoadhesion press and the recovery after thermoadhesion which continue to employ an alternating movement.       

   This alternating movement of offer to the press and of recovery in the latter, even if it is carried out automatically, does not make it possible to achieve assembly rates as high as the possible rates for the production of the blister sheets and for the subsequent packaging of the assemblies respectively formed by a blister sheet and a linerboard mutually assembled, with the result that the operation of mutually assembling the linerboards, as it is currently carried out, slows the entire line for the packaging of a product from the placing under the blister sheet in the final packaging of the assemblies consisting of the blister sheets and of the linerboards mutually assembled. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to overcome this disadvantage, and, for this purpose, the present invention proposes to carry out steps b and c of the abovementioned assembly method by causing a succession of individualized blister sheets and of linerboards, placed in said defined relative position during step a, to travel jointly and continuously, said step a likewise being carried out continuously, which may be considered as being known in principle owing to the existence of machines carrying out the abovementioned automatic method of the prior art. 
   The present invention proposes, furthermore, a machine which, comprising means for carrying out the succession of steps a, b and c, is characterized in that the means for carrying out steps b and c comprise means for causing a succession of individualized blister sheets and of linerboards, placed in their defined relative position during step a, to travel jointly and continuously, said step a itself being carried out by means working continuously, in a way known in principle. 
   A person skilled in the art will easily understand that such a continuous carrying out of steps b and c, after a continuous carrying out of step a, makes it possible to achieve rates of mutual assembly of the blister sheets and linerboards in correlation with the possible rates for the prior production of the blister sheets and for the subsequent packaging of the assemblies formed by the blister sheets and the linerboards in the mutually assembled state, thus making it possible considerably to increase the rates of the lines carrying out in succession the production of the blister sheets, that is to say the containment of the products to be packaged in the latter, the mutual assembly of the blister sheets and of the linerboards and the packaging of the blister sheets and of the linerboards thus mutually assembled. 
   If, as is known, the linerboard comprises a flap having a first main face initially placed in the extension of the first main face of the linerboard and, in said defined relative position, occupying a turned-down position in which its said first main face is laid against the second of said main faces of the blister sheet, at least the first main face of the flap or the second main face of the blister sheet being thermoadhesive or being made thermoadhesive, preferably the flap is placed in said turned-down position, during step a, after the first main faces of the linerboard and of the blister sheet have been laid against one another, and step b is carried out when the flap occupies said turned-down position, in such a way that said mutual clamping pressure likewise forms a pressure for the mutual clamping of the first main face of the flap and of the second main face of the blister sheet, and in such a way that said treatment likewise makes adhesive said main face of these main faces which is thermoadhesive or is made thermoadhesive, said time being selected in such a way that it is sufficient likewise in order to bring about a mutual thermoadhesion of the first main face of the flap and of the second main face of the blister sheet. 
   For this purpose, the machine according to the invention preferably comprises means for placing the flap in said turned-down position during step a, after the first main faces of the linerboard and of the blister sheet have been laid against one another, and the means for carrying out step b are capable of carrying out this step b when the flap occupies said turned-down position, in such a way that said mutual clamping pressure also forms a pressure for the mutual clamping of the first main face of the flap and of the second main face of the blister sheet, and in such a way that said treatment likewise makes adhesive said main face of these main faces which is thermoadhesive or is made thermoadhesive, said time being selected in such a way that it is sufficient likewise in order to bring about a mutual thermoadhesion of the first main face of the flap and of the second main face of the blister sheet. 
   So that adherence to the time necessary for causing a mutual thermoadhesion of the first main faces of the blister sheet and of the linerboard and, where appropriate, a thermoadhesion of the first main face of the flap to the second main face of the blister sheet does not give rise to an excessive overall size of the machine according to the invention, the blister sheets and the linerboards are preferably caused to travel along a curved path during step b. 
   Moreover, this step b may be carried out by any type of known means for applying said mutual clamping pressure and said treatment capable of making adhesive the face or faces which are thermoadhesive or are made thermoadhesive. 
   It is thus possible, for example, to perform the thermoadhesion by ultrasonic applications or else by induction or by thermal conduction or else by any other suitable means. 
   However, it is preferable to use means of thermoadhesion by induction or means of thermoadhesion by thermal conduction which preserve the property of a barrier to air and to moisture possessed, in particular, by PVC and ACLAR, the materials often used to form the transparent part of a blister sheet, especially in the pharmaceutical industry. 
   Thus, according to a preferred embodiment of the method according to the invention, a plurality of electrodes and a plurality of counterelectrodes are circulated continuously in a respective closed circuit, said closed circuits comprising a common limited portion, along which the electrodes and counterelectrodes follow a common path, at the same time being matched in a defined relative position in which they offer a respective plane face toward one another, between an entrance, at which the electrodes and counterelectrodes approach one another, at the same time circulating along said respective closed circuit, and an exit, at which the electrodes and counterelectrodes move apart from one another, at the same time circulating along said respective closed circuit, and step b is carried out by introducing a blister sheet and a linerboard, placed in their said defined relative position during step a, between a mutually corresponding electrode and counterelectrode at the entrance of said common path, and by causing the blister sheet and the linerboard, placed in their said defined relative position, to execute said common path between said mutually corresponding electrode and counterelectrode, as far as the exit, at which the mutual spacing apart of said mutually corresponding electrode and counterelectrode carries out step c. 
   When the comparative dimensions of the linerboard, between its two main faces, and of the projection which the blister forms on the first main face of the blister sheet are such that the blister likewise forms a projection with respect to the second main face of the linerboard in said defined relative position, there is provision for one of the plane faces which the electrode and counterelectrode offer toward one another when they follow said common path to have at least one cell for receiving a blister, and step b is carried out so as to engage the blister in said cell. 
   In other words, in the machine according to the invention, the thermoadhesion means comprise, in this preferred embodiment of the method according to the invention, means for continuously circulating said plurality of electrodes and said plurality of counterelectrodes in said respective closed circuit, and this machine comprises means for introducing a blister sheet and a linerboard, which are placed in their said defined relative position, between a mutually corresponding electrode and counterelectrode at the entrance of said common path, if appropriate so as to engage the blister in said cell, and means for releasing the mutually assembled blister sheet and linerboard from between said electrode and said counterelectrode at the exit of said common path. 
   The term “electrode” is understood here to mean an active member in the generation of the heating necessary for thermoadhesion, and the term “counter-electrode” is understood here to mean a member forming a simple counterpart which is passive in this regard, both and/or either of these members being capable of being active in applying the pressure, which, moreover, is necessary for this thermoadhesion. Thus, within the meaning of the present invention, the electrode may consist of a press plate which incorporates at least one ultrasonic transmitter or at least one inductor or at least one electrical heating resistor, depending on the type of thermoadhesion means which is selected, and, within the meaning of the present invention, the counterelectrode may consist of a press plate simply produced from one or more materials selected so as to cause it to be a compatible counterpart to the electrode. 
   Since the counterelectrodes are simpler in technical terms than the electrodes and less costly, they may be provided in a larger number than the number of electrodes and they may be caused to execute a more complex closed circuit, without this resulting in a prohibitive extra cost of the machine for carrying out the method, as compared with the advantages which may be expected from it. 
   Thus, according to a preferred embodiment of the method according to the invention, the counterelectrodes are caused to execute, upstream of said common path, an upstream path along which their said face faces upward, and they are used, along this upstream path, as vehicles for a respective blister sheet and linerboard during the carrying out of step a. 
   For this purpose, advantageously, the counterelectrodes are produced or selected in such a way that they have respectively said contingent cell, and step a is carried out by successively depositing, flat, by suitable means of the machine according to the invention in a preferred embodiment of the latter:
         the linerboard with the second of its said main faces on said face of a counterelectrode, said hole being placed in register with said cell, and   the blister sheet with its first main face on the first main face of the linerboard, said blister being engaged in said hole and, through the latter, in said cell.       

   Subsequently, if appropriate, that is to say if the linerboard comprises a flap, as mentioned above, the carrying out of step a is continued by folding the contingent flap of the linerboard by suitable means of the machine in order to bring said flap from its initial position into its turned-down position. 
   It will be seen that, owing to the presence of the contingent cell receiving the blister, the counterelectrodes form an especially effective means of ensuring an exact mutual indexing of the linerboards, of the blister sheets and of the counterelectrodes before the path common to the electrodes is executed. 
   Likewise, the counterelectrodes are preferably caused to execute, downstream of said common path, a downstream path which is an integral part of their closed circuit and along which their said face faces upward, in which case they are used, along this downstream path, as vehicles for a respective mutually assembled blister sheet and linerboard. 
   The counterelectrodes may, of course, likewise be used thus, upstream and/or downstream of the common path, as vehicles for the linerboards and for the blister sheets in the absence of a cell in the plane face of the counterelectrodes. In the case of such an absence, the mutual indexing of the linerboards, of the blister sheets and of the counterelectrodes may be ensured by auxiliary means, such as at least one positioning dog integral with each counterelectrode respectively. 
   By contrast, in order to cause the common path of electrodes and of the counterelectrodes to be curved, preferably the closed circuit of the electrodes is circular and the closed circuit of the counterelectrodes is in the form of an arc of a circle coaxial to the closed circuit of the electrodes along said common path. 
   Thus, according to a preferred embodiment of the machine according to the invention, the means for circulating the electrodes in a closed circuit comprise a wheel mounted rotatably about a defined axis and carrying the electrodes, by means allowing a centripetal elastic retraction of the latter independently of one another, in an orientation in which said face of each faces in the centrifugal direction, and a motor for driving the wheel in a defined direction such that said common path is covered from the entrance toward the exit, and the means for circulating the counterelectrodes in a closed circuit comprise an endless conveyor guided in an arc of a circle coaxial to said wheel about the latter and carrying the counterelectrodes in an orientation such that said face of each faces toward said face of a respective electrode along said arc of a circle, and means for intermeshing between said wheel and said endless conveyor, in such a way that the motor for driving the wheel likewise drives the endless conveyor by means of the wheel and in synchronism with the latter. 
   A person skilled in the art will easily understand that there is thus obtained an especially simple embodiment of the means making it possible to cause the electrodes to execute a circular closed circuit and at the same time to ensure a perfect synchronism of respective displacements of the electrodes and the counterelectrodes along their respective closed circuit. A setting of the means provided for elastically opposing the centripetal retraction of the electrodes makes it possible to ensure a setting of the pressure which is applied between these and the counterelectrodes to the blister sheets and to the linerboards occupying their predetermined relative position during the carrying out of step b. 
   Furthermore, means may advantageously be provided for bringing about a coercive centripetal retraction of the electrodes in the event of a stoppage of the drive motor, thus making it possible to avoid maintaining the pressure and heating for too long a time during the carrying out of step b and consequently to avoid bringing about a fusion of the component material of the blister sheet and, where appropriate, of the component material of the linerboard, which may be accompanied by adhesion to the electrodes or counterelectrodes; it is nevertheless prudent however, to eliminate the blister sheets and linerboards which are executing the common thermoadhesion path during such a stoppage of the drive motor. 
   Preferably, to prevent the blister sheets and linerboards from tending to accompany the movement of the electrodes rather than that of the counterelectrodes, once they have crossed their common thermoadhesion path, when the counterelectrodes form vehicles for a respective mutually assembled blister sheet and linerboard, downstream of said common path, each electrode preferably has at least one respective ejection pusher elastically retractable from a defined position in which it projects on said face of the respective electrode. This ejection pusher is retracted at the entrance of the common path under the effect of its application to said face of the counterelectrode by means of the mutually superposed blister sheet and linerboard, and thus remains retracted during the entire coverage of the common path; by contrast, at the exit of the latter, from the moment when the counterelectrode no longer maintains said ejection pusher elastically in a retracted state by means of the respective blister sheet and linerboard, said ejection pusher tends to resume said defined position projecting with respect to the face of the electrode and, thus returning to its said defined position, it pushes back the blister sheet and linerboard in the mutually assembled state and forces them to remain on said face of the counterelectrode. 
   It will be seen that a machine according to the invention has a high simplicity in terms of implementation, thus resulting especially in high reliability in spite of the considerably increased rates, as compared with the prior art, the carrying out of the method according to the invention making it possible to have access to such rates. 

   
     Other characteristics and advantages of the method and of the machine according to the invention will become apparent from the following description relating to a respective nonlimiting exemplary embodiment and from the accompanying drawings which are an integral part of this description. 
     DESCRIPTION OF THE DRAWINGS 
       FIGS. 1 and 2  show respective recto and verso perspective views of the assembly consisting of a blister sheet and of a linerboard with flap, which are assembled by means of the method according to the invention, with an illustration on a larger scale of two details, one of which is partially cut away. 
       FIG. 3  illustrates the main successive steps of the method according to the invention which are used for producing the assembly illustrated in  FIGS. 1 and 2  from a linerboard with flap and from a blister sheet. 
       FIG. 4  shows a side elevation view of part of a packaging machine forming the machine according to the invention. 
       FIG. 5  shows in a side elevation view, and on a larger scale, the parts of this machine which are intended more particularly for carrying out step a of the method. 
       FIG. 6  shows a top view of some details of this part in a direction marked by VI in  FIG. 5 , the viewing direction of  FIG. 5  being marked by an arrow V in  FIG. 6 . 
       FIG. 7  shows, in an enlarged view and in side elevation, the parts of the machine which carry out steps b and c. 
       FIG. 8  shows a view of these parts of the machine partially in section in a plane marked by VIII-VIII in  FIG. 7  and partially in elevation. 
       FIG. 9  illustrates the details of an electrode and of its mounting in a view corresponding to that of  FIGS. 4 to 7 , but further enlarged, partially in section in a mid-plane marked by IX-IX in  FIG. 10 . 
       FIG. 10  shows the same details partially in a view in the direction marked by X in  FIG. 9  and partially in section in another mid-plane marked by X-X in this  FIG. 9 . 
       FIGS. 11 and 12  show, in views similar to those of  FIGS. 4 ,  7  and  9 , but on an intermediate scale between those of  FIGS. 7 and 9 , the cooperation between an electrode and a counterelectrode at two moments in the execution of their common path. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Reference will be made in the first place to  FIGS. 1 and 2  which illustrate an assembly  1 , generally designated by the term “wallet” and produced by the integral assembling, by means of the method according to the invention indicated diagrammatically in  FIG. 3 , of two initially separate components, to be precise a blister sheet  2  and a linerboard  3  which, in the example illustrated, has a flap  4  produced in one piece with it; however, this flap  4  is optional with regard to carrying out the present invention, and a person skilled in the art will easily understand that the steps of the method according to the invention which will be described hereafter and which are associated with the presence of this flap  4  would simply be omitted in the absence of such a flap  4 . 
   The blister sheet  2  generally consists itself of two components integrally assembled by thermoadhesion prior to the carrying out of the method according to the invention, to be precise:
         a sheet  5  of a transparent semirigid thermoplastic material, having two mutually parallel plane main faces  6 ,  7  and thermoformed so as to have, projecting on its main face  6 , that is to say recessed in its main face  7 , at least one blister  8 , to be precise, in the nonlimiting example illustrated,  28  mutually identical and uniformly distributed blisters  8 , this blister  8  or each of these blisters  8  respectively containing, as a nonlimiting example, a tablet or a capsule, not illustrated and not designated, and   a flexible sheet  9  generally formed from a multilayer material comprising, in particular, an aluminum layer having two main faces  10 ,  11 , the first of which is integrally secured flat, in a leaktight manner, for example by thermoadhesion, to the face  7  which it covers, including in the region of the blisters  8 , in order to close the latter in a leaktight manner on all sides, the sheet  9  being selected so as to be tearable at will by a user, for example under the effect of a pressure applied to a blister  8  and transmitting to the sheet  9  by means of the product contained in this blister  8 .       

   The two sheets  5  and  9 , that is to say likewise their main faces  6 ,  7 ,  10 ,  11 , have the same rectangular plane in the example illustrated. 
   Such a design of the blister sheet  2  is well known to a person skilled in the art, and the present invention applies just as well to blister sheets of different design, likewise known, comprising, like the blister sheet  2  illustrated, two plane main faces, to be precise, in the example illustrated, the faces  6  and  11  opposite to the mutual assembly faces  10  and  7  of the sheets  5  and  9 , one of these main faces, to be precise, to this example, the face  6 , carrying in relief at least one blister  8  receiving whatever product, whatever the type of component materials of these blister sheets. 
   The linerboard  3  is itself produced, in one piece with its contingent flap  4 , from a semirigid material, such as cardboard or a thermoplastic. It has two mutually parallel plane main faces  12 ,  13 . Likewise, the flap  4  has two mutually parallel main faces  14 ,  15  which extend the face  13  and the face  12  in a coplanar manner in an initial state of the flap  4  with respect to the linerboard  3 , that is to say in a state prior to the carrying out of the present invention. 
   The linerboard  3  and the flap  4 , that is to say their main faces  12 ,  13 ,  14 ,  15 , have a form identical to that of the main faces  6  and  11  of the blister sheet  2 , that is to say a rectangular form in the example illustrated, with dimensions identical to or slightly greater than those of these faces  6  and  11 . 
   In positions which, respectively on the face  12  of the linerboard  3  and on the face  14  of the flap  4 , correspond to the respective positions of the blisters  8  on the face  6  of the blister sheet  2 , the linerboard  3  and the flap  4  are pierced right through with respective holes  16 ,  17  which have a form similar to that which a blister  8  has at its connection to the face  6 , but a slightly greater dimension, in such a way that, as shown in  FIGS. 1 and 2 , the linerboard  3  can be laid flat, with its face  13 , against the face  6  of the blister sheet  2 , with each blister  8  being engaged in a respective hole  16 , and the flap  4  can be laid flat, with its face  14 , against the face  11  of the blister sheet  2 , with a hole  16  being placed opposite each blister  8 , in order to make it easier to extract the contents of this blister  8  by perforating the sheet  9 . 
   The flap  4  and the linerboard  3  are connected to one another along a straight folding line  18 , illustrated in  FIG. 2  as a material bridge connecting them to one another, this folding line  18  coinciding with a respective one of their longest edges. 
   At least one of the faces  11  and  14  and at least one of the faces  6  and  13  is naturally thermoadhesive or is made thermoadhesive by means of a suitable method known to a person skilled in the art, such as a polyethylene coating, and the method according to the invention is used, in the application illustrated, for the thermoadhesion of the face  13  of the linerboard  3  to the face  6  of the blister sheet  2 , all around the holes  16  and the blisters  8 , and of the face  14  and the contingent flap  4  to the face  11  of the blister sheet  2 , all around the holes  17  and, if appropriate, of the faces  13  of the linerboard and  14  of the contingent flap  4 , around the blister sheet  2 , in order to form the wallet  1  from the blister sheet  2  already produced, on the one hand, and from the linerboard  3  and the flap  4  occupying their initial relative position, on the other hand. 
   For this purpose, as indicated diagrammatically in  FIG. 3 , and using a machine  20 , a currently preferred embodiment of the invention of which is illustrated in  FIGS. 4 to 12 , use is made of a method of thermoadhesion by induction or, also preferably, by Joule effect and thermal conduction, applied to linerboards  3 , with their contingent flap  4 , and to blister sheets  2  travelling continuously, being transported for this purpose by vehicles advantageously consisting of suitable thermoadhesion counterelectrodes  19  which are circulated in a closed circuit and continuously, that is to say always in the same direction and at a constant speed after setting, under the normal operating conditions of the machine  20 . 
   For this purpose, as shown in  FIG. 4 , this machine  20  comprises an endless conveyor  21  comprising two endless belts or two chains  22  mutually juxtaposed in a horizontal direction, not designated, and guided by pairs of grooved wheels or of gearwheels mutually juxtaposed in this direction and mounted rotatably about a respective axis of each pair, said axis being oriented in this direction, to be precise, in the example illustrated, two wheels  23  of the same axis  29  which are supported by a stand  35  of the machine, by means of a known device  36  for tensioning the belts or chains  22 , two wheels  24  mounted rotatably about the same axis  30 , two wheels  25  mounted rotatably about the same axis  31 , two wheels  26  mounted rotatably about the same axis  32 , two wheels  27  mounted rotatably about the same axis  33  and two wheels  28  mounted rotatably about the same axis  34 , the axes  30  to  34  being fixed with respect to the stand  35  of the machine, and the rotation of the wheels  23  to  28  about the respective axis with respect to this stand  35  being a free rotation. 
   The axes  29  to  32  are located at the same level, and the pairs of corresponding wheels define for the conveyor  21  an upper strand  37  active for carrying out the method according to the invention, while the axes  33  and  34  are located at a lower level and the corresponding wheels ensure simply the closing of the circuit of the conveyor  21  in the form of a lower strand  38  which is itself devoid of an active part in carrying out the method according to the invention. 
   More specifically, with reference to a defined direction  39  of coverage of the closed circuit of the belts or chains  22 , the wheels  23 ,  24 ,  25 ,  26 ,  27 ,  28  succeed one another in this order, and the wheels  23  and  24  define a horizontal upstream portion  40  of the upper strand  37 , that is to say of the corresponding path of the counterelectrodes  19 , while the wheels  25  and  26  define a downstream horizontal portion  41  of this upper strand  37  and of this path, at a level identical to that of the portion  40 . Between the pair of wheels  24  and the pair of wheels  25 , the upper strand  37  and said path have a concave curved portion  42  in the form of an arc of a circle, with an axis  43  parallel to the axes  30  and  31 , the strand  37  being guided at this level by means which will be described later. As a nonlimiting example, the axis  143  has been illustrated at a level slightly lower than that of the axes  30  and  31 , with the result that the portion  42  has, with reference to the axis  143 , an angular length slightly greater than 180°, but other choices could be made, without departing from the scope of the present invention, especially as a function of the value which it is appropriate to give the developed length of the portion  42 , bearing in mind the speed of displacement of the conveyor  21  in the direction  39 , the time necessary for ensuring thermoadhesion under conditions which will be described in detail later, and rates to be adhered to in order to integrate the machine  20  into a packaging line. 
   The belts or chains  22  jointly carry a multiplicity of counterelectrodes  19  which succeed one another in the direction  39  and connect to one another the two belts or chains  22  which ensure their transport along the closed circuit of the conveyor  21 , at the same time maintaining a uniform spacing between them. 
   Each counterelectrode  19  has the general form of a plate having a plane useful face  43  which, at the upstream  40  and downstream  41  portions of the upper strand  37  of the conveyor  21 , is horizontal and faces upward, being arranged above the belts or chains  22 . 
   Each useful face  43  has a form substantially complementary to that of the face  6  of the blister sheet  1 , with plane dimensions which correspond to the largest dimensions, of the dimensions of the respective main faces of the blister sheet  2 , of the linerboard  3  and of the contingent flap  4  of the latter, if these dimensions are different. In other words, in the example illustrated, said useful face is rectangular, its largest dimension being orientated in the direction  9 , with reference to the upstream  40  and downstream  41  portions, and it is recessed with as many cells  44  as the face  6  has blisters  8 , with a shaping and positioning of the cells  4  which are as closely as possible complementary to those of the blisters  8  on the face  6 , so as to allow an interlocking effect which will be described later. 
   Approximately in its middle, with reference to the upstream  40  and downstream  41  portions and the direction  39 , each counterelectrode  19  carries, projecting downward, lugs, not designated, for integral securing to the two belts or chains  22 , and, opposite the latter, that is to say below the latter in the region of the upstream  40  and downstream  41  portions, and on either side of the pair of belts or chains  22 , these lugs carry two rollers  45  mounted freely rotatably about an axis  46  parallel to the axes  29  to  34 . In the region of the upstream  40  and downstream  41  portions, the rollers  45  of each counterelectrode  19  bear downward on a respective straight guide  47 ,  48 , while, in the region of the curved portion  42 , the rollers  46  arranged respectively on either side of the pair of belts or chains  22  engage into a respective guide rail  49  of a general shape in the form of an arc of a circle of axis  143 , the two guide rails  49  having a U-shaped cross section open from one of these rails  49  toward the other, so as to receive the respectively corresponding rollers  45  and to retain them both in the centrifugal direction and in the centripetal direction, with reference to the axis  143 , at the same time opposing minimum resistance to the travel of the rollers  46  over the portion  42 . Upstream with reference to the direction  39 , each counterelectrode  19  carries integrally a respective dog  50  which forms a projection with respect to its useful face  43 , immediately upstream of the latter with reference to the direction  39  and laterally with reference to this direction  39 , to be precise on the right of the useful face  43  with reference to this direction  39  in the example illustrated. 
   Thus designed, each counterelectrode  19  is successively used as a vehicle for carrying out a first step of the method according to the invention, in the region of the upstream portion  40 , in a way which will be described in detail here more particularly with reference to  FIGS. 3 to 6 . 
   During this first phase, each useful face  43  of a counterelectrode  19  passes successively, in the direction  39 , opposite three stations  51 ,  57 ,  63 , the last of which may be omitted in the absence of flap  4  on the linerboards  3 . 
   The station  51  is a station for the destacking of linerboards  3 , with their flap  4  occupying its initial position, from a magazine  52 , in which the linerboards  3  with their flap  4  are presented according to a vertical orientation, in a horizontal stack, so as to be offered successively, in the direction  39 , to the destacking station  51 . At this station  51 , a wheel  53 , which is mounted and driven in rotation in synchronism with the conveyor  21  about an axis  54  parallel to the axes  29  to  34  and located at a level higher than that of the strand  37  and is equipped peripherally with suction cups  55  according to a design known per se, successively picks up the linerboards  3 , with their flap  4 , which are presented downstream of the magazine  52  with reference to the direction  39 , in order to deposit them one by one onto the useful face  43  of a respective counterelectrode  19 , in a position which may be gathered from  FIGS. 3 ,  5  and  6  and in which the face  12  of the linerboard  3  rests flat on the useful face  43  of the counterelectrode  19  and in which the holes  16  are placed in the register with the cells  44 . In this position, the flap  4  forms a projection overhung laterally with respect to the useful face  43 , that is to say, more specifically, on the right of the latter with reference to the direction  39 , but a slideway  56 , which is suitably carried by the stand  35  of the machine and forms an overhang in the direction  39  in the region of the station  51  and which bears in a localized way on the face  13  of the linerboard  3  and affords a localized bearing surface for the flap  4 , prevents any tilting of the linerboard  3  and of the flap  4  with respect to the corresponding counterelectrode  19 . The dog  50  of this counterelectrode  19 , butting against the linerboard  3  and/or the flap  4  in the immediate vicinity of their mutual junction, causes the assembly formed by the linerboard  3  and by the flap  4  to accompany the counterelectrode  19  in its movement in the direction  39  toward the following station  57 . 
   This station  57  is a station for the destacking of blister sheets  2  coming from a magazine  58  in the form of a vertical stack, in which the faces  6  and  11  are horizontal and in which the face  6  and the blisters  8  face upward. In the nonlimiting example illustrated, the station  57  comprises a destacker  144  of a known type, comprising four vertical endless screws  145  driven in synchronism with displacement of the conveyor  21  and causing the blister sheets  2  to descend one by one, at each revolution, in order to deposit them one by one between the dogs  146  of an endless conveyor  58  executing a closed circuit, in synchronism with the displacement of the conveyor  21 , about two rolls  59  and  60  of respective axis  61 ,  62  parallel to the axes  29  to  34 , above the upper strand  37  of the conveyor  21  in the region of the upstream portion  40  of the latter. The dogs  146  of the endless conveyor  58  are capable of picking up in succession each of the blister sheets  2  which is presented at the bottom of the stack of the magazine  58  and which is extracted from it by the destacker  144  in order, after having been overturned, to be deposited onto a respective linerboard  3  which itself rests on the useful face  43  of a counterelectrode  19 . The destacking station  57  is set in such a way that, then, each blister  8  is engaged into a respective cell of the useful face  43  of the counterelectrode  19 , at the same time passing right through the linerboard  3  via a respective hole  16 , as a result of which, on leaving the station  57  by being displaced in the direction  39  in the region of the upstream portion  40 , each counterelectrode  19  carries and drives, particularly by the interlocking effect of the blisters  8  in the cells  44  through the holes  16 , both a linerboard  3  and a flap  4 , whose position with respect to the counterelectrode  19  has not changed, and a blister sheet  2 , the face  6  of which rests flat on the face  13  of the linerboard  3 , but the face  11  of which faces upward, as does the face  14  of the flap  4  which is then still arranged laterally with respect to the blister sheet  2 , still overhung with respect to the useful face  43  of the counterelectrode  19 . 
   From that moment on, the interlocking of the blisters  8  through the holes  16  of the linerboard  3  in the cells  44  of the counterelectrode  19  ensures both the drive of the linerboard  3 , with its flap  4 , and of the blister sheet  2  by the counterelectrode  19 , in addition to the action of the dog  50  for this purpose, and the maintaining of a relatively exact positioning, during the travel over the rest of the upstream portion  40 , over the portion  42  and finally over the portion  41 . 
   It will be seen that, instead of thus associating with each linerboard  3  a blister sheet  2  having plan forms and dimensions substantially identical to those of this linerboard and comprising blisters  8  in a number identical to that of the holes  16  of the linerboard  3  and holes  17  of the contingent flap  4 , in relative positions identical to those of these holes  16  and  17 , it would likewise be possible to associate with each linerboard  3  a respective group of a plurality of mutually juxtaposed blister sheets, the plan forms and dimensions of which would complete one another in order, considered as a whole, to correspond substantially to those of the linerboard  3 , and of which the total number of blisters and their relative position would correspond to those of the holes  16  of the linerboard  3  and of the holes  17  of the contingent flap  4  which would thus be used to group the various blister sheets and to secure the various blister sheets of the group integrally to one another. For this purpose, a plurality of successive stations  57  could be provided along the upstream portion  40  of the path of the counterelectrodes  19 , in order to deposit in succession, under the conditions which have just been described, the various component blister sheets of the same group onto a respective location of each linerboard  3  which itself rests on a respective counterelectrode  19 , or else it will be possible to preserve a single station  57  by arranging it in such a way that it is capable, under the conditions which have just been described, of depositing simultaneously one item of the group on each linerboard  3  which itself rests on a respective counterelectrode  19 . 
   The holes  16  and  17  could, of course, have any suitable form and any suitable relative position in each location for receiving a blister sheet of the group. With regard to the present invention, each group of blister sheets thus associated with the same linerboard  3  and with the same contingent flap  4  is subsequently treated as one and the same blister sheet  2 , and the term “blister sheet  2 ” must therefore be understood as meaning both a single blister sheet  2  and such a group of blister sheets. 
   The station  63  is a station for turning down the flap  4 , with its face  14 , onto the face  11  of the blister sheet  2  by folding along the line  18  by means of guides  64  and  65 , the implementation of which comes within the normal capabilities of a person skilled in the art and the first of which bear successively upward and downward on the face  15  of the flap  4 , while the second maintain a downward pressure on the face  11  of the blister sheet  2  in order to maintain it in bearing contact on the face  43  of the counterelectrode  19  by means of the linerboard  3 . Advantageously, this station  57  also comprises, immediately downstream of the guides  64  and  65 , a roller  66  mounted freely rotatably about an axis  67  parallel to the axes  29  to  34 , above the upstream portion  40  of the strand  37 , in order to compress the fold formed between the flap  4  and the linerboard  3  by the folding line  18 . 
   The assembly consisting of the counterelectrode  19 , the linerboard  3  and the flap  4  thus mutually superposed, flat, then passes from the portion  40  to the portion  42 , where thermoadhesion takes place between the blister sheet  2  and the linerboard  3 , on the one hand, and the flap  4 , on the other hand, by passage through a thermoadhesion station  68  which shall be described in more detail with reference to  FIGS. 4 and 7  to  12 . On each counterelectrode  19 , a wallet  1  is thus formed, which subsequently arrives, still driven by the interlocking of the blisters  8  in the cells  44  through the holes  16  of the linerboard  3  and by the dog  50  of the counterelectrode  19 , at the downstream portion  41 , in the region of which is located a station  69  for picking up the wallets  1  thus formed, for example by means of a suction cup device  70  of the type known per se, before each counterelectrode  19  travels over the lower strand  38  of the conveyor  21  in order to return upstream of the portion  40  for the purpose of a new cycle for carrying out the method according to the invention. 
   According to the present invention, at the station  68 , thermoadhesion is ensured while the counterelectrodes  19  continue to be displaced continuously, together with the respective linerboard  3 , flap  4  and blister sheet  2 , thus making it possible for the machine  20  according to the invention to be integrated into a continuous packaging line. 
   For this purpose, each counterelectrode  19  travelling along the curved portion  42  is associated with a respective electrode  71  which accompanies it in its displacement. 
   For this purpose, a plurality of electrodes  71  are carried, uniformly distributed angularly about the axis  143 , by a wheel  60  mounted rotatably about the axis  143  with respect to the stand  35  of the machine and driven in rotation about this axis  143  by means of a, for example, electric, motor  73  simply indicated diagrammatically in  FIG. 8 , under conditions such that, below the axis  143 , and facing the counterelectrodes  19  travelling over the portion  42 , the electrodes  71  are displaced in an arc of a circle of axis  143  in the same direction  74  as the counterelectrodes  19  and at the same angular speed as the latter. 
   For this purpose, advantageously, the wheel  72  itself, driven by the motor  73 , is used for driving the conveyor  21 . For example, for this purpose, the wheel  72  has peripherally as many notches  75  open in the direction of movement away from the axis  143  as electrodes  71 , said notches being uniformly distributed angularly about the axis  143  in the same way as the latter, but being offset laterally with respect to the latter, respectively on either side of these, in a direction parallel to the axis  143 , and the lugs, not designated, for the connection between each counterelectrode  19  and its rollers  46  carry integrally, projecting toward the axis  143 , a respective bar  76  parallel to the axes  29  to  34  and  143  and capable of meshing with a respective notch  75  when the counterelectrode  19  in question travels over the portion  42  of the path of the conveyor  21 . For this purpose, the mutual angular spacing between notches  75  succeeding one another in the direction  74  with reference to the axis  143  is identical to the angular spacing between two bars  76 , that is to say likewise between two counterelectrodes  19  which succeed one another in this same direction in the region of the portion  42 . For this purpose, a suitable dimensioning of the components of the station  68  is within the normal competence of a person skilled in the art. 
   Thus, the rotation of the wheel  72  in the direction  74  brings successive pairs of notches  74  into engagement with successive bars  76  and coercively brings about a displacement of the conveyor  21  in perfect synchronism with the rotation of the wheel  72 , so as to present a respective electrode  71  successively face to face with each counterelectrode  19 . 
   The synchronization of the destackers  51  and  57  and of the conveyor  70  of the pick-up station  69  could have been ensured in the same way, but it is preferable to have electrical means for the synchronization of respective drive motors, not illustrated, with the motor  73  for driving the wheel  72  and the conveyor  21 . 
   The association of each electrode  71  with the respectively corresponding electrode  19  must be accompanied by the application of a mutual bearing pressure, flat, between the main faces, which are thermoadhesive or are made thermoadhesive, of the blister sheet  2  of the linerboard  3  and of the flap  4  respectively, to be precise both and/or either of the faces  6  and  13  and both and/or either of the faces  11  and  14 . 
   For this purpose, when the radial position of the useful faces  43  of the counterelectrodes  19  with reference to the axis  143  is kept fixed by the effect of the guidance of the rollers  45  in the curved guide rails  49 , a mounting, elastically retractable in the direction of the axis  143 , of the electrodes  71  on the wheel  72  is used, this mounting being capable, furthermore, of allowing a coercive centripetal retraction of the electrodes  71  located opposite the counterelectrodes  19  which correspond to the portion  42  in the event of a stoppage, accidental or not, of the motor  73  or, more generally, of the machine  20 . 
   This mounting will now be described, more particularly with reference to  FIGS. 7 to 12 . 
   As shown more particularly in  FIG. 8 , the wheel  12  consists essentially of two disks  77 ,  78  of the same diameter and of the same axis  143 , which have a respective edge face rotationally cylindrical about this axis and recessed with notches  75  which correspond to one another in pairs in a direction parallel to the axis  143 , and the electrodes  71  are arranged between these two disks  77  and  78 , the second of which has been omitted in FIGS.  4  and  7  in order to make it possible to illustrate the electrodes  71  and their mounting. 
   The two disks  77  and  78  have here, toward one another, a respective plane face  79 ,  80  perpendicular to the axis  143 . 
   The various electrodes  71 ,  20  in number in the nonlimiting example illustrated, are mounted on that face  79  of the disk  77  which carries integrally as many slideways  81 , radially with reference to the axis  143 , as electrodes  71 . Each of these slideways  81 , arranged in relief on the face  79 , has a mid-plane  82  including the axis  143  and common to a respective pair of notches  75  which correspond to one another in a direction parallel to this axis  143 ; the mid-planes  82  are thus uniformly distributed angularly about the axis  143  in the same way as the electrodes  71  and the pairs of notches  75 . 
   Each slideway  81  itself carries, with the possibility of relative sliding in a respective direction  83  of the respective mid-plane  82 , said direction  83  being perpendicular to the axis  143 , a respective carriage  142  which itself forms a guide for sliding in the direction  83  for a respective slide  84 . For this purpose, the carriage  142  carries integrally, but preferably adjustably in the direction  83 , a yoke  85 , on which the slide  84  is mounted slideably in the direction  83  and which has a free end zone  86  projecting from the slide  84  toward the axis  143 . In this free end zone  86 , the yoke  85  carries two rollers  87 ,  88  mounted rotatably on it about the same axis  89  parallel to the axis  143  and located in the plane  82 , the first of these rollers having a mid-plane  90  parallel to the axis  143  and common to the slide  84  as a whole and to the corresponding electrode  71 . The other roller  88  is offset toward the wheel  72  with respect to the slide  84 . 
   The position of the slide  84  with respect to the yoke  85  in the direction  83  is fixed during the operation of the machine  20 , but can be adjusted by means of a screw  91  of axis  92  coinciding with the intersection of the planes  90  and  82 . This screw  91  has, toward the axis  143  and toward the yoke  85 , an end  93  mounted freely rotatably about the axis  92  in the yoke  85 , without any other possibility of relative displacement; said screw has, opposite its end  93 , a head  94 , on which action can be taken at will in order to rotate it in one direction or the other about the axis  92  with respect to the yoke  85  and to the slide  84 , and it is engaged by means of a threaded portion  95 , between its head  94  and its end  93 , in a complementarily tapped coaxial hole  96  of the slide  94 . A screw  97 , engaged along an axis  98  perpendicular to the axis  92  into a complementarily tapped hole of the slide  98 , makes it possible at will to immobilize the screw  91  in the selected position with respect to this slide  84 . 
   In mutually symmetric positions with respect to the plane  82 , the slide  84  is pierced, along axes  100  parallel to the axis  92  and located in the plane  90 , with two passages  101  rotationally cylindrical about the respective axis  100 , which pass right through said slide between a plane face  102  perpendicular to the axes  100  and facing toward the axis  143  and a plane face  103  likewise perpendicular to the axes  100 , but facing in the direction of movement away from the axis  43 . Each of the passages  101  has engaged in it, freely slideably along the respective axis  100 , without any other possibility of relative displacement, an unthreaded portion  104  of a respective bolt  105  which, moreover, has a head  106  opposite the face  102  for bearing on the latter about the respective passage  101 . 
   When each head  106  bears in this way on the face  102 , each of the unthreaded portions  104  passes right through the slide  84  along the respective axis  100  and forms with respect to the face  103  of this slide a projection over an equal distance for the two bolts  105  which are identical to one another. 
   Opposite the head  106  along the respective axis  100 , each of the bolts  105  has a threaded end portion  107  screwed coaxially into a rigid plate  108  equipped internally with a cooling fluid circuit, not illustrated, and itself serving as support to the respective electrode  71 . 
   The plate  107  has a general orientation perpendicular to the axes  92  and  100  and, in particular, has, perpendicularly to these axes, two plane faces  109 ,  110 , the first of which faces toward the axis  143  and toward the face  103  of the slide  84  and the second of which faces in the direction of movement away from the axis  143  and carries the electrode  71  integrally by means of a thermal insulation layer  111 , in a position in which the electrode  71 , fixed with respect to the support plate  108 , has respectively toward the latter and opposite the latter a respective plane face  112 ,  113  perpendicular to the axes  92  and  100 ; the first of these faces  112  and  113  is placed in integral bearing contact on the face  110  by means of the thermal insulation layer  111 , whereas the second is free, facing the direction of movement away from the axis  143  and forms a useful face of the electrode  71 . 
   Between the faces  109  and  103  is interposed, respectively around each unthreaded portion  104  of a bolt  105 , a spring which consists here of a coaxial sleeve  114  of an elastically compressible material, the two sleeves  114  being identical to one another in their geometry and their composition. 
   Each electrode  71  incorporates heating means, for example in the form of at least one inductor in the case of thermoadhesion by induction or in the form of at least one electric heating resistor associated with temperature control means and placed in thermal conduction relation with the useful face  113  of the electrode  71  through the mass of the latter. Thus, in the nonlimiting example illustrated, the electrode  71  houses two electrical heating resistors  150  which extend along its useful face  113  and are associated with a thermocouple  151 . 
   The heating means incorporated in the electrode  71  and the cooling circuit incorporated in the plate  108  are connected respectively to electricity supply means and to means for the circulation of a cooling fluid by means of rotary joints of axis  143 , of which  FIG. 8  illustrates only the rotary joint  115  for connecting the electrodes  71  to electricity supply means. 
   Each of the faces  113  is plane and has a contour substantially identical to that of the useful face  43  of a counterelectrode, in such a way that, during the rotation of the wheel  72  in the direction  74  about the axis  143  with respect to the stand  35  of the machine and during the synchronized displacement of the conveyor  21 , each useful face  113  of an electrode  71  comes progressively into place opposite the useful face  43  of a counterelectrode  19  carrying the wallet  1  already shaped, but not having undergone thermoadhesion, at the transition between the portions  40  and  42 , then remains placed opposite this useful face  43  during the entire travel over the portion  42 , at the same time applying to the wallet  1  heating and pressure capable of bringing about thermoadhesion, and then moves apart from the face  43  of the counterelectrode  19  and from the wallet  1  which has thus undergone thermoadhesion, at the transition between the portion  42  and the portion  41  travelled over by the wallets  1  which have undergone thermoadhesion. 
   The travel time over the path portion  42  determines the application time of the pressure and heating, but, by action on the speed of displacement of the electrodes in the direction  74  and of the counterelectrodes in the direction  39 , on the number of electrodes  71  and on the developed length of the portion  42 , on which depends the number of matched electrodes and counterelectrodes for applying pressure and heating to a wallet to undergo thermoadhesion, it is possible to ensure the rate of the machine  20  is adapted to the rates of machines which may be located upstream and downstream in a packaging line, as a person skilled in the art will easily understand. 
   Preferably, the face  113  of each electrode  71  has forms and dimensions directly complementarily to those of the useful face  43  of a counterelectrode  19 , considered without its cells  44 , in such a way that, when the counterelectrodes  19  cross the portion  42 , the useful face  113  of a respective electrode  71  is superposed exactly on the face  43  of a respective counterelectrode  19  by means of the shaped wallet  1  which is undergoing thermoadhesion. 
   As will easily be understood by a person skilled in the art, by virtue of the mounting which has just been described, each electrode  71  occupies at rest, that is to say in the absence of any stress, a defined position with respect to the slide  84 , in which defined position the sleeves  114 , if appropriate subjected to the same compression prestress along the respective axis  100 , maintain a maximum mutual spacing between the faces  119  and  103 . With respect to this initial position, however, the electrode  71  may be retracted elastically in the direction of an approach with respect to the slide  82  at the expense of an elastic compression of the sleeves  114  along their axis  100 , the sleeves  114  tending, however, to return the electrode  71  into its initial position with respect to the slide  84 . This effect is utilized in order to apply to the wallet  1 , during thermoadhesion, the mutual application pressure of the faces, laid against one another, of the various components of this wallet  1  during the crossing of the portion  42  by the counterelectrodes  19 . 
   For this purpose, the roller  87  is intended to afford a bearing surface for the assembly consisting of the yoke  85  and of the slide  84  in a centripetal direction with respect to the wheel  92 , at the same time cooperating, for this purpose, with a cam track  114  on which it bears toward the axis  143 . 
   The cam track  114  consists of an edge face, facing the direction of movement away from the axis  143 , of a flat cam  115  perpendicular to the axis  143  and adjustable between two defined limiting orientations about the axis  143  with respect to the stand  35  of the machine, to be precise an operating orientation, in which it is illustrated in  FIGS. 4 ,  7 ,  8 ,  11  and  12  and with reference to which it will now be described, and a safety orientation, in which it is rotated through 180° with respect to this operating orientation about the axis  143  in a way which is not illustrated, but will become apparent from the rest of the description. The change from the operating orientation to the safety orientation may be made by voluntary control by an operator and, advantageously, automatically in the event of a voluntary or accidental stoppage of the motor  73 ; the change from the safety orientation to the operating orientation preferably takes place solely by control and on the condition that the motor  73  is restarted under the normal conditions of use of the machine  20 . 
   The cam track  114  comprises, with regard to this possibility of orientation of the cam  115 , two portions  116  and  117  rotationally cylindrical about the axis  143 , with a respective angular development of the order of 180°, these portions  116  and  117  being connected to one another by means of two transition portions  118 ,  119  having an angular development of the order of a few degrees and designed so as not to form an obstacle to their being crossed by a roller  87 . 
   In the operating orientation of the cam  115 , the portion  116  of larger diameter faces downward, that is to say toward the curved path portion  42  of the counterelectrodes  19 , whereas the portion  117  of smaller diameter faces upward. 
   Thus, during the rotation of the wheel  72  in the direction  74  with respect to the stand  35  of the machine, each roller  87  travels successively over the portion  117  of the cam track  114 , this corresponding to an inactive position of the corresponding electrodes  71 , then arrives in the transition zone  118 , at that time facing toward the upstream portion  40  of the path of the conveyor  21 , while the useful face  113  of the corresponding electrode arrives opposite the useful face  43  of a counterelectrode carrying a wallet  1  in the folded state, but not having undergone thermoadhesion, advantageously retained on the useful face  43  of the counterelectrode  19  by a curved extension  120  of the guides or slideways  65 , coaxially surrounding the circular path of the useful faces  43  of the counterelectrodes  19  at the crossing of the wheels  24 , that is to say at the transition between the upstream portion  40  and the curved portion  42 , in order then to come to bear on the face  15  of the flap  4 , until, during the continuation of the joint movement of the electrodes  71  and counterelectrodes  19 , the face  113  of the electrode  71  itself applies such pressure. 
   Subsequently, the roller  87 , moving progressively away from the axis  143  at the crossing of the transition portion  118 , thus likewise moving the slide  84  and the electrode  71  away from the axis  143 , comes into contact with the portion  116  of the cam track  114  and remains in contact with this portion  116  during the whole of the common circular path of the electrodes  71  and of the counterelectrodes  19 . During the whole crossing of the portion  116  of the cam track  114 , the yoke  85  remains at the same distance from the axis  143 , but, by a suitable adjustment of the screw  91 , making it possible to adjust the position of the slide  84  and, with it, of the useful face  113  of the electrode  71  with respect to the yoke  85  in the absence of stress on the electrode  71 , the result is such that, by being applied with its face  113  to the wallet  1 , itself applied to the face  43  of the counterelectrode  19 , the electrode  71  is forced to retract elastically, that is to say by the elastic compression of the sleeves  114 , toward the slide  84  and toward the axis  143  over a predetermined stroke which governs the reaction which the sleeves  114  oppose elastically to this retraction and, consequently, the pressure with which the face  113  bears on the face  43  by means of the wallet  1  during thermoadhesion.  FIG. 12  illustrates this relative positioning for maintaining the wallet  1 , during thermoadhesion, in a state of elastic compression between the faces  113  and  44  of the electrode  71  and of the counterelectrode  19 . 
   Consequently, when the electrode  71  and the counterelectrode corresponding to it arrive in the immediate vicinity of the wheels  25  which define the transition between the portion  42  and the portion  41  of the path of the counterelectrodes  19 , the roller  87  crosses the transition portion  119  of the cam track  114  and allows a retraction of the assembly consisting of the yoke  95 , of the slide  84  and of the electrode  71  toward the axis  143  as far as a relative position which corresponds to the crossing of the portion  117  of the cam track  114  by the roller  87 . 
   This retraction is advantageously implemented by means of another cam track  121  of suitable shaping, defined by a second cam  122 , illustrated only in  FIG. 8  for the sake of clarity, which cam  122  is flat, perpendicular to the axis  143  and integrally fastened, flat, to the cam  115  and by means of its cam track  121  affords a bearing surface for the rollers  88  in the direction of movement away from the axis  143 . The cam track  121  is homothetic to the cam track  114  with reference to the axis  143 , in order to retain each roller  87  permanently in bearing contact on the cam track  114 , and therefore does not need to be described any further. 
   In the safety orientation, not illustrated, of the cam  115  and, with it, of the cam  122 , the portion  117  of the cam track  114  faces downward, that is to say faces the curved path portion  42  of the counterelectrodes  19 , and, by means of the rollers  88  associated with the corresponding electrodes  71 , the cam track  121  applies a coercive withdrawal movement toward the axis  143  in order to interrupt the contact between the useful face  113  of the electrodes  71  in question and the wallet  1  resting on the useful faces  43  of the corresponding counterelectrodes  19 , in order to prevent excessive heating of these wallets  1  which are subsequently preferably eliminated, although the return of the cams  115  and  112  to their operating orientation, at the restarting of the motor  73  if the passage of the cams  115  and  122  to their safety position was brought about by a momentary stoppage of said motor, in some cases makes it possible to terminate thermoadhesion under good conditions. 
   There could possibly be the fear that, instead of following the counterelectrodes  19  at the transition between the portion  42  and the portion  41 , by remaining engaged by means of the blisters  8  in the cells  44  of the useful face  43  of these counterelectrodes  19 , the wallets  1  which have undergone thermoadhesion tend to follow the rotational movement of the electrodes  71 . 
   To prevent this, each electrode  71  advantageously has associated with it at least one ejection pusher which, if necessary, detaches from the useful face  113  of the electrode  71  a wallet  1  which would tend to stick to it. 
   In the example illustrated, each electrode  71  has associated with it two pushers  123 , each of which is in the form of a straight rod with a respective axis  124  parallel to the axis  92  and which are located respectively on either side of the mid-plane  90  and slightly in front of the plane  82  with reference to the direction  74 . 
   Each of these pushers  123  passes coaxially, without contact, through the electrode  71  via a coaxial hole  125  of the latter, in order to prevent a heating of the pushers  123 , and is mounted elastically retractably toward the axis  143  in a respective bush  126  screwed into the support plate  108 , from a position illustrated in  FIGS. 9 and 10 , in which each ejection pusher  123  forms a projection on the face  113  and which each pusher  123  occupies as soon as stress is applied to it in the direction of retraction with respect to the face  113 , especially when the electrode  71  is applied with this face  113  to a wallet  1 , itself in bearing contact on the useful face  43  of a counterelectrode  19 . As soon as this bearing contact ceases, however, each pusher  123  tends elastically to resume its position projecting with respect to the face  113  and thereby detaches from the latter the wallet  1  which would possibly tend to remain stuck there. 
   A person skilled in the art will easily understand that the embodiment of the invention which has just been described, both in terms of the method and in terms of the machine, is only one nonlimiting example, with regard to which numerous variants can be provided, without thereby departing from the scope of this invention. 
   In particular, a person skilled in the art will easily adapt this embodiment to the situation of linerboards  3  having no flap  4  and/or to the situation of blister sheets  2  comprising a single blister  8 , the number of cells  44  then being limited to a unit, as are the number of holes  16  of the linerboard  3  and the number of holes  17  of the contingent flap  4 . 
   A person skilled in the art will also easily adapt this embodiment to the situation of linerboards  3  equipped with a plurality of flaps other than the flap  4 , which are articulated on the linerboard  3  directly or by means of the contingent flap  4  and are intended to remain freely articulated, in the state not turned down; during passage through the thermoadhesion station  68 , in order subsequently to be turned down onto the linerboard  3  or the flap  4 , if appropriate at the same time containing a booklet, a notice or a promotional article, and fastened in the turned-down position, in particular in a repositionable way, to the linerboard  3  or the flap  4  or else to one another. In such a case, guide means, the design of which is within the normal capabilities of this person skilled in the art, will be provided for retaining these other flaps against inopportune turning down during passage through the successive stations  51 ,  57 ,  63 ,  68  and, if appropriate,  69 . 
   Likewise, a person skilled in the art will easily understand that, by adaptions coming within his normal capabilities, the method and machine according to the invention may be applied to the assembling together with a linerboard not only of a blister sheet, as defined above, in a commonly accepted sense of this term, but also other types of packaging of one or more doses of a product, for example fluidic product, or of one or more individual articles, to be precise, for example, to the assembling together with linerboards of pouches or sachets for the packaging of a sample of cosmetic products, of food products or of upkeep products. Consequently, within the meaning of the present invention, the term “blister sheet” will be understood as meaning any type of packaging of one or more doses of a fluid or solid product or of one or more individual articles, whether this packaging is flexible or semirigid or rigid, provided that this packaging lends itself to a presentation in the state assembled together with a linerboard, in particular in the form of a wallet, as described above. Moreover, within the meaning of the present invention, the term “blister” will be understood as meaning any localized overthickness which the blister sheet, within the meaning of the present invention, can have, in particular in relation to the presence of its contents, in a prefabricated way or not. When it is not possible or is not desirable to utilize the penetration of one or more blisters of the blister sheet, within the meaning of the present invention, in one or more cells of a counterelectrode through one or more holes of the linerboard, in order to ensure an exact relative positioning, a joint drive and a protection of the blister sheet and of its contents against compression between the electrode and the counterelectrode, under the conditions described, use can be made, for all or part of these various effects, of a punctiform adhesion of the blister sheet to the linerboard during its depositing onto the latter at the destacking station of the blister sheets and/or of the production of a sidewalk around the location of the blister sheet on the linerboard, by the folding of suitable flaps of the latter, either between the destacking station for the linerboards and the destacking station for the blister sheets or between the destacking station for the blister sheets and the thermoadhesion station, by suitable means for the machine which are known per se to a person skilled in the art, and it is possible to ensure the drive of the linerboards and then that of the linerboards together with the blister sheets by means of dogs similar to the dogs  50  and carried by the counterelectrodes likewise serving in this case, preferably, as vehicles during the entire application of the method according to the invention. 
   Furthermore, it goes without saying that a machine according to the invention may be equipped with means for detecting any malfunctioning of the various components of these successive stations, in particular in terms of the presence and of the correct positioning of the linerboards  3 , with their contingent flaps  4  and/or their other contingent flaps, and of the blister sheets  2 , and with means for detecting and ejecting the wallets  1  which are faulty for one reason or another. The selection and implementation of such means are within the normal capabilities of a person skilled in the art.