Abstract:
A method for sealing a surface ( 13 ) of a body ( 11 ), wherein a thin material ( 21 ) is applied to the surface ( 13 ), and the material is connected to the surface by melting due to mechanical stimulation.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally concerns a sealing method and, more particularly, toward a method for sealing one surface to another surface using an intermediate temporarily meltable article. 
     2. Description of Related Art 
     There are various known methods for sealing surfaces. These are based on the application of a protecting layer by means of varnishing or by gluing. The disadvantage of these methods is that, in particular, edges and corners of chipboard, parquet floors or wood fiberboards cannot be sealed sufficiently. Thus, for example, on a correspondingly treated parquet floor the problem arises that moisture penetrates, especially through the lateral surfaces of the boards, which causes moisture expansion of the material. In addition these methods are complicated, costly, and inflexible, and require complex apparatuses. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to create a method that avoids the named problems. 
     The sealing method according to the invention is based on applying a thin material to the surface to be sealed and on connecting the material to this surface by temporary melting using heat, which is caused by mechanical stimulation (by means of a piezo-element). The thin material is, for example, a film (or foil) material or a strip. The thin material is connected adhesively to the body to be sealed or to its surface, respectively, by means of partial, temporary melting, such that a permanent sealing is achieved, which guarantees a sufficient sealing against moisture and other environmental influences. The temporary melting is advantageously carried out without a thermal heat source, by means of heat caused by friction due to mechanical stimulation, advantageously by vibrations. The frequency of the vibrations is typically located at the upper end of the audible region or in the ultrasonic region. With heat caused by friction the material can be melted in a controlled way. By application of pressure the filling of pores and cavities in the surface to be sealed is achieved. Due to the large shearing effect the melted material has a very low viscosity, such that even capillary cavities are filled. The depth of penetration of a specific material can be adjusted, among others, by adjusting frequency and amplitude or duration of the application of the vibration. The method is applicable to practically all surfaces of a body. With a suitable arrangement it is possible to seal large surfaces continuously or in sections. The method can be applied in stationary or in flexible manner. By means of suitable devices it is, for example, possible to seal large surfaces (e.g. floors of gymnasiums, any type of lining, etc.). The material used for sealing can, if required be provided with decorative elements such as patterns or images. It is, for example, possible to seal a carrier with a film with color print, such that the impression of a real parquet floor is created. A decorative layer can also be processed separately. It is not a condition of the invention that all areas are sealed. Rather, in certain cases it is sufficient for critical areas only to be treated with the method of the present invention. 
     The method is advantageously used for sealing surfaces of porous, fibrous materials such as wood, chipboard, cork, cardboard, fiberboard and also concrete, clay, etc. The invention is characterized, among other things, in that it is applicable for continuous processing. Because no solvents are required the method does away with lengthy drying periods and complicated apparatuses for drying. The invention takes advantage of the short and locally restricted melting of an advantageously thermoplastic material. It is advantageous that, due to the very short melting and cooling periods, no significant waiting periods arise. Furthermore, due to the short processing time, the melted material is processed in an extremely sparing manner. 
     The characteristics of the surfaces can be adjusted by means of applying several films. It is, for example, possible to combine a first layer with decorative patterns with a further layer that is particularly resistant to abrasion. This multi-layer technology can be applied in one or several process steps. As the used materials are usually such that they can be melted thermally it is possible to apply several layers at intervals. Functional edges (plug or snap connections) can be sealed permanently. 
     Surfaces treated according to the invention can also be connected together by renewed, mechanical stimulation resulting in an effect with further depth. Thus, it is possible to stimulate flooring that consists of a plurality of individual parts (slabs, tiles, boards) with edges being in mutual contact with each other, such that these edges are permanently bound to each other. In addition, or as an alternative, other means for connecting such edges, adhesives can also be used. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and further features of the invention will be apparent with reference to the following description and drawings, wherein: 
     FIG. 1 shows a diagrammatic overview of the inventive method; 
     FIG. 2 shows a detail of FIG. 1; and, 
     FIG. 3 shows the application of the method to a groove. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows, in a diagrammatic manner, main steps of the method according to the invention. Panels  10 ,  11 ,  12  are shown, the top sides  13  or the narrow sides respectively of which are sealed. Panels  10 ,  11 ,  12  are guided past a processing device  1  by conveying means  2  in the direction of arrow P. The conveying means  2  consist of a plurality of conveying rollers  3  and  4  that are rotatable around their axes and are in interaction with the panels  10 ,  11 ,  12  such that they support the panels  10 ,  11 ,  12  and guide them past the conveying device  1 . The conveying means  2  are mounted on supports which, for clarity reasons, are not shown in detail and they are driven by a corresponding drive (not shown in detail), such as a chain drive, an electric motor, or a hydraulic drive. 
     FIG. 2, which is an enlarged view of a portion of FIG. 1, shows the processing device  1 , a panel  11  being processed and conveying rollers  3  and  4 . A storage reel  20 , onto which a tape  21  is wound, serves as a storage device. The tape  21  is unwound over first and second guiding rollers  22 ,  23  and is positioned on the surface to be sealed. The second guiding roller  23  presses the tape  21  onto the surface  13  of the panel  11  with a specified force F 1 . The movement of guiding rollers  22 ,  23  and storage reel  20  are matched to each other such that the tape  21  is transferred to the surface  13  to be sealed and, if so required, is subject to a predetermined tension. The storage reel  20  and guiding rollers  22 ,  23  are rotatably mounted around axes  27 ,  28 ,  29 , respectively. The processing device  1  is mounted in stationary manner and the panel  11  moves in relation to it in the direction of arrow P and guided by guide means  3 ,  4 . After passing below roller  23 , the panel  11  passes a sonic head  24 , which is functionally coupled with the panel  11  and the tape  21 . The tape  21  is connected with the surface  13  through temporary melting. The melting is advantageously carried out via mechanical stimulation such that the tape  21  and/or the surface  13  is melted partially due to friction heat. By means of pressure, shown diagrammatically by an arrow F 2 , the melted materials are additionally connected. The sonic head  24  is designed such that it corresponds to the surface to be processed. Accordingly, the surface to be processed, especially in the region around the edges  30 ,  31 , is sealed effectively. The sonic head  24 , in this embodiment protrudes over edges  30 ,  31  of panel  11 . Thus, it is also possible to process tapes  21  that are wider than the thickness of the panel  11 , such that the sealing reaches beyond the surface  13 . An overlap of several layers is possible. If required, sonic heads with other characteristics can be used. The resonator  24  is brought into vibration by an actuator  25 . The stimulating vibrations are advantageously generated by means of a piezo-element (not shown in detail) coupled to sonic head  24  (sonotrode). Depending on the field of application other sorts of mechanical stimulation can be used. At the end of panel  11  a trimming device  26  cuts off the tape  21 . The trimming device  26  is advantageously designed such that it positions the tape  21  for processing the next panel  12  (see FIG.  1 ). 
     FIG. 3 shows, in a very simplified manner, how a profiled groove  35  of a panel  11  is sealed. The groove  35  is part of a snap or plug connection for connecting the panel  11  to further panels or other bodies (not shown in detail) being formed accordingly. Processing of this counterpart is carried out in analogy to the method described here and therefore is not explained in detail. 
     A tape  21  is pressed against a surface  35  of a panel  11  by means of a sonic head  24 . Due to the friction heat generated by vibration of sonic head  24  the advantageously thermoplastic tape  21  (or an equivalent material with a corresponding coating) is temporarily melted and pressed into the surface  36 . This process is indicated diagrammatically by arrows  37 . The sonic head  24  is pressed against surface  36  of groove  35 , furthering penetration of the melted material into the surface. Beforehand, the tape  21  is brought into groove  35  in a continuous manner and, if necessary, is fixed by suitable means, in order to prevent unwanted shifting. The (relative) movement between panel  11  and sonic head  24  during processing is shown by an arrow  38 . The sonic head  24  enters the groove  35  at the beginning of the groove  35 . Further sonic heads are used for sealing other surfaces (not shown in detail). The sonic head  24  has a shape that is adapted to the surface to be sealed, and is advantageously designed such that a plurality of surfaces can be processed simultaneously. Undercuts can also be treated with suitably designed sonic heads. The sealing of the surface is carried out continuously or in sections. The other surfaces are processed with accordingly shaped sonic heads (not shown in detail). The design of the sonic heads determines the pressure exerted on the surface. A sonic head can comprise several parts, movable relative to each other, such that it adapts to the outline. Snap or plug connections between parts can be made permanent and tight by renewed melting of the sealing material. 
     The specialist may, with knowledge of the present invention, apply it to other bodies and their surfaces.