Patent Publication Number: US-11639628-B2

Title: Automatic machine and automatic method for sealing the perimetric edge of the insulating glazing unit having irregular geometry

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the 35 U.S.C. § 371 national stage application of PCT Application No. PCT/EP2018/072908, filed Aug. 24, 2018, where the PCT claims priority to, and the benefit of, Italian application no. 102017000101114, filed Sep. 11, 2017, both of which are herein incorporated by reference in their entireties. 
     FIELD OF APPLICATION 
     The field of application is the one according to the preamble of claim  1 . 
     BACKGROUND ART AND RELATED PROBLEMS 
     Currently it is known to deposit the rigid spacer frame  3  or the flexible spacer profile  5 , pre-spread with sealant  6  and/or adhesive  6 ′, on a glass pane  2  to then mate the assembly with a second glass pane  2 ′ and seal it along the entire cavity of the external peripheral region so as to constitute the so-called insulating glazing unit  1 . The operation can also be multiple in order to obtain the insulating glazing unit  1  constituted by three glass panes  2 ,  2 ′,  2 ″ and two frames  3 ,  3 ′ or spacer profiles  5 ,  5 ′, as well as n glass panes  2 ,  2 ′,  2 ″,  2 ′″, etc. and n−1 frames  3 ,  3 ′,  3 ″, etc. or spacer profiles  5 ,  5 ′,  5 ″, etc. 
     These glass panes  2 ,  2 ′, etc., being derived from upstream treatment processes, which despite being accurate are however not free from imperfections, can have geometries that are not regular as regards the dimensions and shape and especially flatness. 
     It is indeed in these situations, although not only for these situations, that the solutions of the invention according to the present application are essentially important, since the background art seals the mentioned cavity by working correctly only in the case of regular geometries. 
     In particular, since non-flatness is meticulously classified by appropriate standards, for example the American standards ASTM C 1036-11 for flat glass panes, ASTM C 1048-12 for tempered glass panes, ASTM C 1172-14 for laminated glass panes, said non-flatness must constitute a data entry toward the machinery and said machinery must be provided with contrivances that render these defects irrelevant since they are solved by means of predominantly mechatronic devices. 
     Thus, irrelevance of the inaccurate geometry of the glass panes with respect to the process for sealing the perimetric cavity can only be achieved by following the irregularities of the glass panes, especially since the user who purchases the machinery reasonably expects that it can, and must, process the glass panes as they are available on the market and since the manufacture of the glass panes cannot be the subject of a complaint if the flatness errors fall within the rather permissive standards, for example the listed ones or other similar ones. 
     Assuming that the subsequent use of the insulating glazing unit  1 , i.e., in the door or window or in continuous faces or in structural faces, is known, in detail the insulating glazing unit  1  is constituted by the composition of two or more glass panes  2 ,  2 ′,  2 ″,  2 ′″, etc., separated by one or more spacer frames  3 ,  3 ′,  3 ″, etc., generally made of inorganic material such as aluminum or stainless steel or mixed inorganic/organic material, the latter being generally PVC (polyvinyl chloride, but not only), which are generally hollow and microperforated on the face that is directed inward, the spacer frames containing, in their hollow part, hygroscopic material  4  and being provided with a butyl sealant  6  on the lateral faces (constituting the so-called first seal), or by spacer profiles  5 ,  5 ′,  5 ″, etc. and the chamber (or chambers) delimited by the glass panes  2 ,  2 ′,  2 ″,  2 ′″, etc. and by the spacer frame (frames)  3 ,  3 ′,  3 ″, etc.,  5 ,  5 ′,  5 ″, etc., being able to contain air or gas  8  or mixtures of gases  8  which give the insulating glazing unit particular properties, for example thermally insulating and/or soundproofing properties. Recently the use of the spacer profile  5  having an essentially rectangular cross-section, optionally containing two receptacles on its sides designed for the butyl sealant  6 , made of expanded synthetic organic material (by way of non-exhaustive indication: silicone and EPM) which embeds in its mass the hygroscopic material  4  and is provided on its sides or part thereof with an adhesive  6 ′ useful for mechanical bonding with the glass panes, has also become widespread. 
     The joining between the glass panes  2 ,  2 ′,  2 ″,  2 ′″ etc. and the spacer frame (frames)  3 ,  3 ′,  3 ″, etc. or spacer profile (profiles) converted into a frame (frames)  5 ,  5 ′,  5 ″, etc. is obtained by means of two levels of sealing, the first one (also known in the jargon as primary)  6  having the function of providing a hermetic seal and an initial bonding between these components and affecting the lateral surfaces of the frame and the portions of the adjacent glass panes, which has already been mentioned earlier (butyl, thermoplastic sealant), the second one (also known in the jargon as secondary)  7 , typically constituted by a bi-component elastomeric sealant, such as polysulfide (PS) or polyurethane (PU) or silicone (SI), processed at ambient temperature, but also constituted by single-component sealant of the type processed at ambient temperature or of the hot-processed type, which has the function of providing the final cohesion between the components and the mechanical strength of the joint between them and affecting the compartment constituted by the outer curved surface of the spacer frame  3 ,  3 ′,  3 ″, etc.,  5 ,  5 ′,  5 ″, etc. and by the internal faces of the glass panes up to their edge (see  FIG.  1   ). 
     In the case of a spacer profile  5  made of expanded synthetic material, the first level of sealing is replaced (in this case losing the hermetic sealing function) or can be integrated (in this case preserving the hermetic sealing function) by an adhesive  6 ′, for example an acrylic one, already spread on the lateral faces of the spacer profile, and covered by a removable protective film (see  FIGS.  1 D and  1 F , in which the film is already removed). 
     The glass panes  2 ,  2 ′,  2 ″,  2 ′″ etc. used in the composition of the insulating glazing unit  1  can have different shapes as a function of its use, for example the external glass pane (external understood with respect to the building) can be normal or reflective or selective (in order to limit the heat input during summer months) or layered (also known as laminated, constituted by two or more glass panes which are intimately connected by one or more membranes made of PVB=polyvinyl butyral) or armored (for intrusion prevention/vandalism prevention/bulletproofing functions) or laminated and tempered (for safety functions) or combined (for example reflective and laminated in order to obtain a combination of properties); the internal glass pane (internal understood with respect to the building) can be normal or with low emissivity (in order to limit the dispersion of heat during winter months) or laminated and tempered (for safety functions) or combined (for example low-emissivity and laminated in order to obtain a combination of properties). In particular, the situations of glass panes which are layered, tempered and layered+tempered are the ones that are most affected by the defect of non-flatness. 
     From the simple summary presented it is already evident that a manufacturing line, in order to obtain the insulating glazing unit product  1 , requires many processes in sequence and in particular comprises the process of second sealing, to which the present application relates with improving and innovative interventions. 
     The processes for the production of the insulating glazing unit  1 , each requiring a corresponding and particular machine to be arranged in series with respect to the other complementary ones, are, by way of non-exhaustive example and at the same time not all necessary, the following: EDGING on the peripheral face of the glass pane in order to remove any coatings in order to allow and maintain over time the bonding of the primary sealant  6  and of the secondary sealant  7 ; BEVELING of the sharp edges of the glass pane, both to eliminate the margin defects introduced with the cutting operation, which potentially may trigger cracks, and to reduce the risks of injury in the subsequent handling both of the glass panes  2 ,  2 ′,  2 ″,  2 ′″, etc. and of the finished insulating glazing unit  1 ; WASHING of the individual glass panes, with alternation of internal glass pane/any intermediate glass panes/external glass pane (the orientation being the one defined earlier); APPLICATION OF THE SPACER FRAME: the spacer frame  3 ,  3 ′,  3 ″, etc., filled with hygroscopic material  4  and spread on its lateral faces with a thermoplastic (butyl) sealant  6 , which has sealing functions against the entry of humidity and the escape of the gas  8 , manufactured beforehand in machines which are external with respect to the production line of the insulating glazing unit  1 , is applied to one of the glass panes that constitute the insulating glazing unit  1  in an adapted station of the production line of the insulating glazing unit  1 ; as an alternative, a continuous strip of spacer profile  5 ,  5 ′,  5 ″, etc. is unwound from a spool and is applied to one of the glass panes until it also forms a closed frame, which is manufactured directly in adhesion against one of the glass panes, after removing the protective film, on the same production line of the insulating glazing unit  1 ; FILLING WITH GAS of the chamber (chambers) thus obtained and immediately subsequent MATING AND PRESSING of the glass panes/frame (frames) assembly; 
     SECOND SEALING of the assembly of components: glass panes  2 ,  2 ′,  2 ″,  2 ′″, etc., spacer frame  3 ,  3 ′,  3 ″, etc.,  5 ,  5 ′,  5 ″, etc., at the perimeter. The invention according to the present application relates in particular to new and innovative components in order to allow the operation of the machine that performs said process in the conditions in which the insulating glazing unit  1  as assembled prior to sealing is not sufficiently planar (first type of irregularity) and/or its peripheral geometry is not exactly (second type of irregularity) the one of the data entry that derives either from the management system or from readings performed only in a spot manner, i.e., not along the entire perimeter. 
     The search for patent prior art, filed in the same sector and describing machines and methods for the execution of the second sealing, leads to a very large number of inventions which relate to the solutions for the dosage and feeding of the secondary sealant  7  to the head and thus to the extrusion nozzle, in which the sealing product is distributed proximate to the outer curved surface of the rigid spacer frame (frames)  3 ,  3 ′,  3 ″ etc. or of the flexible spacer profile (profiles)  5 ,  5 ′,  5 ″ etc. in order to join it (them) mechanically to the glass panes  2 ,  2 ′,  2 ″,  2 ′″, etc., and up to alignment with the edges of the glass panes or with the edge of the smallest glass pane  2 ′ m ,  2 ″ m  (in the case of insulating glazing units with glass panes  2 M,  2 ′ m ,  2 ″ m  which are offset, as in  FIGS.  1 C,  1 E,  1 F ) and sometimes (the case of  FIG.  1 E ) with sealant product that is distributed (in the jargon spatulated) also against the face of the larger glass pane  2 M for the part that protrudes with respect to the smaller glass pane (panes)  2 ′ m ,  2 ″ m  and constitute a sealing barrier with respect to humidity, which not must not penetrate inside the insulating glazing unit  1  and with respect to the filling gas  8 , which must not escape toward the outside of the insulating glazing unit  1 . 
     These inventions, being widespread and therefore common and known since 1980, are neither listed nor commented, but only presented in  FIGS.  5   a ,  5   b ,  6   a ,  6   b    and  7  for the part that relates to the path of the sealing products or product toward the perimetric joint of the insulating glazing unit  1 , since this is a process that is useful also as a preamble of the present invention. Rather, it is pointed out that nearly all of this art has never indicated solutions to ensure that the perimetric joint is always followed by the extrusion nozzle or nozzles (the case of an insulating glazing unit constituted by more than two glass panes) even in case of non-flatness of the insulating glazing unit. At the most, the background art has presented solutions, albeit improper ones, for balancing the extrusion nozzle toward the irregularity of the perimeter of the insulating glazing unit, but assuming that its flatness is regular. 
     The only invention that provides suggestions for solution with respect to the first type of irregularity (non-flat insulating glazing unit) is U.S. Pat. No. 7,922,842 B2, with Italian priority TV2008A000032 dated 20 Feb. 2008, in the name of this same Applicant as the present application. 
     An invention that provides suggestions for solution with respect to the second type of irregularity (perimeter of the insulating glazing unit that does not correspond to data entry) is AT 4030912 B dated to 10 Nov. 1993, in the name of Lisec Peter. 
     These background art documents of the second type have the following drawbacks. 
     The first one describes a sensor the feedback of which acts on the synchronous transverse axis Z for the positioning of the nozzle or nozzles in order to arrange it (them) in the centerline of the cavity (cavities) of the perimetric joint; however, the adjustment might become unstable due to a drift effect, causing the tipping of the insulating glazing unit toward the work regions, particularly if of limited height. 
     The second one does not anticipate, in terms of function or in terms of means, which are in any case complex and therefore expensive, and achieves a precarious result, with respect to the content of the present application. 
     The aim of the present invention is to provide a device and a method that allow, always within the concept of performing the perimetric sealing of the joint of the insulating glazing unit  1 : 
     following of the irregularity in the flatness of the insulating glazing unit; following the mismatch between theoretical position and actual position of the perimeter of the insulating glazing unit and therefore of its peripheral joint; 
     safety in the process from the point of view of accident prevention; superior qualitative results with respect to those of the background art. 
     Within this aim, an object of the present invention is to provide a device and a method that allow to overcome the drawbacks of the prior art. 
     DESCRIPTION OF THE INVENTION 
     The summary description of the drawings and the detailed description of a way of carrying out the invention will clarify how the invention according to the present application can be embodied. 
    
    
     
       DESCRIPTION OF THE FIGURES 
         FIG.  1    is a schematic view of the peripheral portion of the insulating glazing unit  1  in a non-exhaustive exemplifying series of possible combinations:  1 A normal;  1 B triple glazing unit with internal glass pane with low-emissivity coating;  1 C external glass pane with selective coating and offset with respect to the internal glass pane with low-emissivity coating;  1 D tempered external glass pane, internal glass pane with low-emissivity coating;  1 E layered external glass pane, offset with respect to the internal glass pane with low-emissivity coating;  1 F layered external glass pane offset with respect to the remaining two glass panes, of which the internal one has a low-emissivity coating.  FIGS.  1 A,  1 B,  1 C and  1 E  show the rigid frame  3  made of metallic profile (typically aluminum or stainless steel or a combination of stainless steel/plastic), which is hollow and filled with hygroscopic material  4 , while  FIGS.  1 D and  1 F  show the frame of the flexible type  5 , which embeds in its mass the hygroscopic material  4 , but for the purposes of the description the solution indicated for the frame is irrelevant. The two types of sealant used are highlighted in cross-section: in black, the butyl sealant  6 , which has the function of initial bond between the components and of seal (first seal and primary sealant), in the case of a flexible frame  5  it is replaced with an acrylic adhesive  6 ′ (shown emphasized, since it has an actual thickness of a few μm) or the combination of the acrylic sealant  6 ′ and of the butyl sealant  6  applied between the receptacles of the lateral surfaces of the frame and the glass panes, as visible in  FIGS.  1 D and  1 F , is used; in dashed lines, the polysulfide (PS) or polyurethane (PU) or silicone (SRI) sealant  7 , which has the function of a mechanical coupling to the edge and of a seal (second seal and secondary sealant) applied between the outer curved surface of the frame and the faces of the glass panes up to the edge of the glass panes or pane  2 ′ m  that has the smallest dimensions (in the case of offset glass panes). The secondary sealant  7  also provides a contribution, albeit a smaller one than the primary sealant  6 , to the seal against the entry of humidity and the escape of the gas  8 .  FIGS.  1 D,  1 E,  1 F  show the cases for which the present invention has an essential relevance, i.e., the cases of large dimensions of the insulating glazing units (both in terms of sides of the glass panes and of thickness thereof, the panes being of the tempered and/or laminated type) such as for example architectural work such as the one required in Apple stores, which reach dimensions of 12 m×3.3 m. And it is indeed for these cases and in any case in general that the present invention has an essential relevance, the glass panes of these types, due to their extensions, entailing flatness errors that are absolutely far greater than the accepted tolerance in misalignment between the extrusion nozzle and other devices of the sealing head toward the centerline of the cavity to be sealed. 
         FIG.  1 E  indicates a situation for which, all the more, the placement of the extrusion nozzle must be matched with the face of the larger glass pane  2 M since the nozzle, in addition to filling the perimetric cavity of the insulating glazing unit  1 , must spread the sealant  7  also and simultaneously against the face of the glass pane  2 M that protrudes with respect to the glass pane  2 ′ m , i.e., the lateral gap for the supply of the sealant which is located in the same nozzle must remain mated with the face of the glass pane  2 M, which due to what has been described above is not certainly flat. 
       The internal/external orientation is visually identified with icons that represent the sun (outer side) and the radiator (inner side). In all the figures, the secondary sealant  7  is referenced in the condition of filling the perimetric joint, since its extrusion is the main subject matter of the present invention. 
       From these figures one deduces that the insulating glazing unit  1  can have multiple shapes and that the machines for the application of the second seal must be both special and versatile, for example to seal the insulating glazing unit  1  composed of two glass panes, the one composed of three glass panes, the one with offset glass panes, and the one composed of three or more than three glass panes, of which one or more, larger and therefore offset with respect to the remaining ones, characteristics of machines that are already established in the background art, and these machines must work by mating with the actual position of the perimetric joint, which does not correspond to the ideally precise theoretical position, which does not occur or occurs partially in the machines according to the background art. 
         FIGS.  2 ,  3 ,  4    are views of the complete machine (automatic sealing machine according to the background art), which includes the subject matter of the present invention, respectively in its general main views: front, from above, from the side, with identification of the horizontal axis H [actuated by the means assembly  100  of the known type, constituted both by the motorized pseudo-horizontal conveyors that act on the lower edge  1   d  of the insulating glazing unit  1  and by the suction cup carriage  100 ′ which acts on the face of the insulating glazing unit  1 , while the insulating glazing unit  1  remains resting on the motorized pseudo-horizontal conveyors, which are slightly inclined with respect to the horizontal plane, and on a pseudo-vertical sliding plane  900 , which is slightly inclined with respect to the vertical plane and is provided with free wheels or with an air cushion], of the vertical axis V (assembly  200  of the known type) and of the rotation axis θ (assembly  300  of the known type). 
         FIGS.  5   a ,  5   b    show the opposite views of the dosage devices of the sealant  7  of the bi-component type; the perspective views are duplicated and arranged mutually opposite for the visibility of all the component elements, all of which belong to the background art. 
         FIGS.  6   a ,  6   b    show the opposite views of the dosage devices of the sealant  7  of the mono-component type; the perspective views are duplicated and arranged mutually opposite for the visibility of all the component elements, all of which belong to the background art. 
         FIG.  7    is a view of the circuits and of the logic and power controllers, again according to the background art which operates on an insulating glazing unit  1  having an ideal (parallelepiped) geometry. 
         FIG.  8    is a view of the actual geometry of the insulating glazing unit  1  in solid lines and of the ideal one in dashed lines. The aberrations of this geometry are evident, both in the deviation with respect to the theoretical plane (curvature in one direction, the longitudinal one) and in the deviation from the theoretical perimeter (irregularity of the rectangle presented as one side which is not perpendicular to the adjacent ones). 
         FIG.  9    is a view of the method of adaptation of the sealing devices (nozzle and probe according to  FIG.  7   , but with the nozzle modified according to the evolutions of the present invention) to the actual geometry of the insulating glazing unit  1 , performed according to the invention according to the present patent application. 
         FIG.  10    is a view of the distribution of the sensors in the extrusion head  300 . 
         FIG.  11    is a view of the distribution of the sensors in the conveyor  601  upstream of the machine. 
         FIG.  12    is a view of the system for following the irregularities of the perimeter of the insulating glazing unit by means of feedback on the axes H, V and θ. 
         FIGS.  13   a ,  13   b ,  13   c  and  13   d    are respectively views of the insulating glazing unit  1  in its shapes: rectangular  1 , polygonal  1 ′, curved  1 ″, mixed  1 ′. In the case of the rectangular shape, the sides are designated in the sequence of the sealing operation, which occurs therefore according to the following progression: vertical side  1   a , corner  1   a / 1   b , horizontal side  1   b , corner  1   b / 1   c , vertical side  1   c , corner  1   c / 1   d , horizontal side  1   d , corner  1   d / 1   a.    
         FIG.  14    is an example of insertion of the automatic sealing machine  1000  in the production line of the insulating glazing unit  1  (perspective view) and does not comprise: the electrical/electronic panel, the control post and the protection devices. 
         FIG.  15    is an example of insertion of the automatic sealing machine  1000  in the production line of the insulating glazing unit  1  (plan view) and includes: the electrical/electronic panel  11 , the control post  12  and the protection devices, designated generated by the reference numeral  13 , of the type of mechanical barriers or optical barriers or laser barriers or electrosensitive mats or zone scanners, etc., since particular attention is dedicated not only to the functional, qualitative, and production aspects that are typical of the content of the present invention but also to the aspects related to accident prevention. 
     
    
    
     The products: insulating glazing unit  1 , glass pane  2 ,  2 ′,  2 ″,  2 ′″, etc., spacer frame  3 ,  3 ′,  3 ″, etc.,  5 ,  5 ′,  5 ″, etc. and additional components thereof are designated by single-digit numbering optionally provided with indices or letters. In particular, in order to distinguish the various possible shapes of the insulating glazing unit  1 , as already anticipated, the numeral  1  designates the most frequent situation (rectangular), the numerals  1 ′ and l′″ designate the situations that can in any case be processed with the devices according to the present invention (polygonal and mixed), the numeral  1 ″ designates the shape that is rarely requested and can be processed with integration of devices by the present invention (curvilinear). 
     The components interfaced with the automatic sealing machine are designated by two-digit numbering. 
     The main components of the inventive device according to the present application  500 ,  600  and of the known correlated devices  100 ,  200 ,  300 ,  400 ,  900  are designated by three-digit numbering, where the ones that contains two zeros refer to assemblies or units, while the others refer to the respective details. 
     The machines that belong to the production line of the insulating glazing unit  1  are designated by four-digit numerals, in the order according to the description, reserving the numeral  1000  for the automatic sealing machine. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     We now move on to the detailed description of a way of carrying out the invention. 
     In order to describe a way of embodying the invention, which comprises all the equivalents, reference is made to  FIGS.  2 ,  4 ,  8    for the general concepts and to  FIGS.  9  to  12    for the details suitable to make one or more of the possible embodiments of the invention fully comprehensible to the person skilled in the art. 
     What is shown partially or not shown in  FIGS.  2 ,  3 ,  4    regarding the sealing machine per se is instead understood as known, and therefore not requiring a detailed description (since it is part of the background art), since both the prior art documents described earlier and the numerous additional ones, since the sector is very crowded with industrial property titles, and the knowledge of the person skilled in the arts do not require any clarification for the construction of these parts that relate to the automatic sealing machine, which are essentially constituted by the assemblies:  100  for motion along the synchronous horizontal axis H of the glass pane through its lower edge  1   d ;  100 ′ for the motion along the synchronous horizontal axis H of the insulating glazing unit  1  through its front face or sometimes rear face;  200  for the motion of the sealing head along the synchronous vertical axis V;  300  for the extrusion head that rotates about the synchronous polar axis θ;  400  for the dosage units;  900  for the pseudo-vertical conveyors for the support of the insulating glazing unit  1 . 
     A few details related to the background art are instead referenced with regard to the path of the sealant  7 , since it is correlated with the function of filling the perimetric joint. 
     The dosage unit  400  is constituted by the dosage device of the base product B and by the dosage device of the catalyst product C, which, being each in synchronous electrical tie, can deliver the flow of base product and the flow of the catalyst product in the stoichiometric ratio required by the manufacturer of the secondary sealant  7  (typically 10:1 by volume, but any ratio can be adjusted by means of simple inputs in the control panel  12 ). Of course, in the case of a mono-component sealant the dosage device  450  is a single one, since the catalyst product is not present. 
     The dosage device of the base product comprises the following essential components:  401 B plunger or syringe;  402 B cylinder or chamber;  403 B seal;  404 B ballscrew;  405 B ball bearing nut;  406 B mechanical transmission, for example of the sprockets/chain type;  407 B mechanical reduction unit;  408 B synchronous electric motor. Obviously, these components are coupled partly to an upper plate and partly to a lower plate which are connected by tension members, structural elements which are shared and used by the dosage device B of the base product and by the dosage device C of the catalyst product, as can be seen in  FIGS.  5   a    and  5   b.    
     The dosage device of the base product comprises the following auxiliary components, all of which also belong to the background art: valves, pressure transducers, pressure gauges, protections against overpressures, etc. 
     The dosage device of the catalyst product comprises the following components:  401 C plunger or syringe;  402 C cylinder or chamber;  403 C seal;  404 C ballscrew;  405 C ball bearing nut;  406 C mechanical transmission, for example of the sprockets/chain type;  407 C mechanical reduction unit;  408 C synchronous electric motor, coupled as mentioned earlier. 
     The dosage device of the catalyst product also comprises the auxiliary components as mentioned earlier. 
     In the case of mono-component sealant  7 , the diagram is the same but a single dosage device (series  450  shown in  FIGS.  6   a  and  6   b   ) is involved. 
     The operating logic of all these components is shown schematically in  FIG.  7   , which is intuitive to understand, since on the delivery side the flow-rate of the dosage assembly is equal to c 1 ×S 1 +c 2 ×S 2 ; where c 1  and c 2  are respectively the speeds of the syringes of the base products and of the catalyst product, actuated by means of the actuation systems of the motors  408 B and  408 C, and S 1  and S 2  are the corresponding cross-sections, and on the destination side the same flow-rate corresponding to the relative speed of the extrusion nozzle  301 /side of the insulating glazing unit  1  multiplied by the cross-section S of the perimetric joint, i.e., v×S. Where S is the product of the width w of the spacer profile  3 ,  5  and the distance d of its outer curved surface from the margins of the glass panes  2 ,  2 ′ as measured continuously by the probe  304 , the position is fedback by means of the potentiometer  305  toward the programmable logic controller (PLC)  306 . 
       FIG.  7    shows other components, such as the flow control valve  302 , the mixer  303  for example of the static type, the operator interface (HMI)  307 , arranged in the control post  12  for communicating with the PLC. 
     In detail, as regards the logic and power controls used to perform the dispensing of the sealing product  7  to the nozzle  301 , they are managed by the PLC  306 , the following are the main INPUTS and OUTPUTS: 
     Inputs: 
     #w=width of the spacer frame 
     #d=distance of its outer curved surface from the margin of the glass panes 
     #v=relative speed of the peripheral region of the side of the insulating glazing unit  1 /extrusion nozzle  301   
     #signals from the pressure transducers 
     #feedbacks from the synchronous motors  408 B and  408 C 
     Outputs: #signals toward the actuation systems (not shown in the figure) of the synchronous motors, such as to embody the equation v×S=c 1 ×S 1 +c 2 ×S 2 . 
     Other parameters are resident in the PLC, such as for example the cross-sections S 1  and S 2  of the syringes, since they are constant data. 
     This description refers to the most complete case of the bi-component sealant. Obviously, it can be applied also to the case of the mono-component sealant simply by eliminating the parts that describe the catalyst fluid. 
     But it is indeed the  FIG.  7    that is misleading, since it represents the insulating glazing unit  1  in a perfect or ideal geometric situation: a parallelepiped. One can imagine how and how much the relationships described above which regulate the process are compromised in the actual situation, which is distorted both in terms of solid flatness and in terms of peripheral planar geometry, which is not dealt with by the background art, shown emphasized in  FIG.  8   . 
     And it is in this situation, which in any case is always true, that the inventive concept described hereinafter provides a solution in terms of stability of the process, quality of the seal, safety for the operator. The principle of following the perimetric joint is shown in  FIG.  9   ; how to render executable and especially stable with respect to the background art this following can be deduced from  FIGS.  10 ,  11  and  12    described hereinafter as preferential methods or combination of preferential methods of execution of the invention. 
     For following the deviation of the geometry of the insulating glazing unit along the axis Z, the sensors, for example of the ultrasound type,  504 , or of the optical type  505 , or based on another physical value, arranged in the extrusion head  300 , as indicated in  FIG.  10   , are used; their feedback, processed by means of software that incorporates mathematical steps and did not exist at the time of prior art U.S. Pat. No. 7,922,842 B2, acts on the actuator  506 , which intervenes by moving the front part of the extrusion head  300  along the direction Z, which is transverse with respect to the plane of the insulating glazing unit  1 , in the two directions. This software analyzes the stability condition of the insulating glazing unit  1 , since it is arranged in the vertical conveyors  900 , which are typically inclined by  5 ÷8 degrees with respect to the vertical plane and subject to the force of gravity, and stops the corrective action of the actuator  506  to prevent the insulating glazing unit  1 , especially if of limited height, by virtue of the action of the nozzle  501  which penetrates toward the perimetric cavity of the joint of the insulating glazing unit since it is cantilevered with respect to the plate  502 , and thus also the probe  304  are pushed toward a possible situation of tipping toward the work regions due to an interference against one of the internal faces of the glass panes  2 ,  2 ′. 
     As an alternative, for following the deviation of the geometry of the insulating glazing unit  1  along the axis Z, the array of sensors, for example of the ultrasound type,  602 , is used which is arranged in the pseudovertical conveyor  601  upstream of the actual sealing machine, its feedback acting on the actuator  506 , which intervenes by moving the front part of the extrusion head  300  along the direction Z, which is transverse with respect to the plane of the insulating glazing unit  1 , in the two directions. The array of sensors can be replaced by a scanner, for example of the laser type  603 , which is already in use with other functions in insulating glazing unit production lines and is arranged in the pseudovertical conveyor  601 : in both of these measurements of the deviations of the geometry of the insulating glazing unit  1  performed in the conveyor  601 , the entire surface of the insulating glazing unit  1  is mapped and a data file is built which relates to the deviations of the face of the insulating glazing unit that rests on the conveyor  601  with respect to the plane of the conveyor, the file being transmitted to the sealing machine  1000  in order to move the front part of the extrusion head  300  along the direction Z, which is transverse with respect to the plane of the insulating glazing unit  1 , in the two directions by virtue of the intervention of the actuator  506 . Of course again under the management of the software according to the preceding paragraph. 
     Also as an alternative, and positively in order to avoid the situations of instability due to the drift effect described in the description of the background art, both the signals obtained by means of the sensors  503 ,  504 , which belong to the extrusion head  300 , and the signals obtained by means of the array of sensors  602  or by means of the scanner  603 , which belong to the conveyor  601 , can coexist, so as to have a redundant control, which is important so that the nozzle  501  that protrudes toward the perimetric cavity of the joint of the insulating glazing unit since it cantilevers out with respect to the plate  502  and likewise the probe  304  do not push the insulating glazing unit  1  toward a possible situation of tipping toward the work regions due to an interference against one of the internal faces of the glass panes  2 ,  2 ′. 
     For following the deviation of the geometry of the insulating glazing unit  1  in the sense that its perimeter, regardless of the non-flatness since it is managed as above, deviates also from the theoretical geometric shape, the extrusion nozzle assembly is modified with respect to the monolithic one  301  of the background art shown in  FIG.  7   , the arrangement of which adjacent to the margins of the glass panes  2 ,  2 ′ is performed by diving with compensation entrusted to elastic systems (springs), splitting it into a plate  502  and into the actual nozzle  501  as shown in  FIG.  12   . Between these two elements, a transducer  503  sends a feedback signal which interacts with the known actuation systems that control the axes H, V and θ, respectively of the assemblies  100 ,  100 ′,  200 ,  300 , alone or in a combination of two or in a combination of three, so as to keep constant, according to a set point value that can be entered by the operator by means of the operator interface arranged on the post  12 , the protrusion of the nozzle  501  with respect to the plate  502 , so that the nozzle performs the extrusion of the sealant  7  in optimum conditions as regards the shape of the perimetric joint to be obtained, in particular of its depth d. If the depth d is significant, it is in fact appropriate to increase this protrusion.  FIGS.  10  and  12    show the important function of these components; in particular  FIG.  12    shows, in the details shown in circles, the conditions of alignment of the nozzle  501  with the plate  502  and the condition of protrusion of the nozzle  501  with respect to the plate  502 . 
     The control performed by the process PLC toward the actuators of the axes H, V and θ on the feedback signal of the transducer  503  appropriately should be of the PID type (i.e., with parameters P=proportional, I=integral, D=derivative, which can be set independently both for prompt response and to avoid drift situations). 
     In general and with reference to the most widespread configuration of the insulating glazing unit, i.e., the one having a rectangular shape  1 , the succession of the sides being sealed, in the case of a single-head sealing machine  300 , is typically the following: first vertical side  1   a , second horizontal upper side  1   b , third vertical side  1   c , fourth horizontal lower side  1 D.  FIG.  7    shows the situation of a machine according to the background art, with entry of the insulating glazing unit  1  from the left and exit toward the right;  FIGS.  9  and  13 A  show the situation of the machine  1000  according to the present invention, with entry of the insulating glazing unit  1  from the right and exit toward the left. 
     The inevitable transients of the flow of sealant at the corners where the nozzle  501  must rotate through 90° are already managed, as in the background art, by reduction of the relative speed between the nozzle  501  and the peripheral region of the insulating glazing unit  1  and a corresponding reduction of the flow-rate of sealant until the relative speed is eliminated and the flow-rate is eliminated in order to allow the rotation of the head  300  that supports the nozzle  501  and the closure of the valve  302 . 
     The present invention is susceptible of numerous constructive variations (with respect to what can be deduced from the drawings, the details of which are evident and eloquent), all of which are within the scope of equivalence with the inventive concept; thus, for example, the arrangement of the sensors, the actuation means which can be electric electrical, electrical-electronic, pneumatic, hydraulic and/or combined, etc., the control means, which can be electronic or fluidic and/or combined, etc. 
     One variation that is already established in the known part of the invention, which however resides practically only in the software and therefore uses the same devices for sealing insulating glazing units having a rectangular shape  1  described so far, is the one constituted by the logical combination of the synchronous actuations, respectively: of horizontal translation along the axis H of the insulating glazing unit  1  by means of synchronous motors; of vertical translation along the axis V of the head  200  by means of a synchronous motor; of rotation according to the axis θ of the head  300  by means of a synchronous motor; of actuation of the flow control element  302  of the nozzle  501 ; so as to allow sealing on the insulating glazing unit  1 ′ having a shape other than rectangular since it is a regular or irregularly polygonal or on an insulating glazing unit  1 ″ which has a shape other than rectangular since it is curvilinear or on an insulating glazing unit  1 ′″ which has a shape other than rectangular since it contains both rectilinear and curvilinear parts. For these shapes also, the sensors, which belong to the inventive part of the invention  503 ,  504 ,  505 ,  602 ,  603 , shown in  FIGS.  10 ,  11  and  12   , all operate as already described and shown for the case of the insulating glazing unit  1  having a rectangular shape. 
     The constructive details can be replaced with other technically equivalent ones. The materials and the dimensions may be any according to the requirements in particular arising from the dimensions (base and height) and/or from the shape of the glass panes  2 ,  2 ′,  2 ″,  2 ″, etc. that constitute the insulating glazing unit  1 . 
     The description given above and the corresponding figures refer to an automatic sealing machine  1000 , which includes the innovative devices of the series  500 ,  600  for uniform, functional and precision filling of the peripheral joint of the insulating glazing unit  1  by means of a secondary sealant  7  with respect to which sealing machine the original machines (mating unit and press, optionally with gas filling, etc.) are arranged to the right; it is easy to imagine a description and corresponding figures in the case of mirror-symmetrical or otherwise different arrangements, for example including a variation of the work direction of the line. 
     INDUSTRIAL APPLICATION 
     The industrial application is of assured success, since machines for the automatic execution of the second seal of the insulating glazing unit  1  have developed particularly in the last decade, so much that the proprietor of the present application has already marketed over four hundred of them, but these automatic sealing machines have the limitations described earlier. 
     Currently, the types of insulating glazing units have undergone a surprising increase; it is sufficient to think of structural glazing, which extends over heights of more than one storey of the building, or of commercial glazing, which reaches lengths of over 12 meters, and of the consequence that the large extensions of the surface entail the use of thicknesses of the glass panes which are also important and the use of configurations of glass panes that range from tempered to laminated and accordingly their deviation from planar geometry, which is already per se present due to the large dimensions, is therefore even worsened. Moreover, the range of automatic sealing machines according to the background art has turned out not to be suitable for this parallel development of the final products, or only partially able to solve the problem. 
     The insertion of the present invention in the production line of the insulating glazing unit is shown in  FIGS.  14  and  15    (perspective view and plan view), as an evident confirmation of the assured success in industrial application, in view of the by now established but always evolving diffusion of these lines. 
     Moreover, the machine according to the present invention can be easily implemented in existing lines, since as it performs the last treatment of the process for the manufacture of the insulating glazing unit it is a matter of replacing the obsolete machine with this innovative machine without altering the placement of all the upstream machines, since one intervenes only on the terminal part of the line. 
     Not least, the fact of including devices and logic systems dedicated to the control of the static stability of the insulating glazing unit during the sealing process, in addition to implementing further configurations which fall within the concept of machinery of the “Industry 4.0” type, provides elements dedicated to safety which are complementary to the ones designated by the reference numeral  13  in the description. 
     The disclosures in Italian Patent Application No. 102017000101114 from which this application claims priority are incorporated herein by reference. 
     Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.