FIELD OF THE INVENTION

The present invention concerns a fixation system specifically designed for fixing elements or parts of elements made of different materials, e.g. for fixing an element made of a plastic material to an element made of a metal material.

The invention further relates to a method for fixing elements or parts of elements made of different materials using the inventive fixation system.

The system and method of the present invention can solve the problems of the systems and methods of the prior art, and namely afford simple and effective fixation, do not require large working spaces, optimize fixation times, avoid the aesthetically unappealing use of glues, and address material compatibility issues.

BACKGROUND OF THE INVENTION

Systems and methods for fixing elements or parts of elements made of different materials, typically elements made of metal materials to be fixed to elements made of plastic materials, are known in the art.

This situation frequently occurs, for example, in the automotive industry, in which a body or crankcase element, often also having an aesthetic function, is required to be assembled with other parts made of plastic materials, such as ABS, ABS/PMMA, PST, PVC, PMMA, PET, PC, etc.

Such assemblies are known to be obtained by means of mechanical fasteners, which are fairly quick to use and may also be quite accurate, but are generally aesthetically unpleasant, because they are visible from the outside.

A known alternative is gluing, which nevertheless requires longer times and is generally inaccurate, and further results in poor aesthetic effects.

Mechanical fasteners also generally require the formation of visible holes, required for insertion of the fastening means, possibly consisting of common screws, rivets, threaded metal inserts, etc.

On the other hand, gluing requires positioning, aligning and bonding using doublesided adhesive tapes, or chemical products, such as glues or mastics, which may have reasonable bonding times, but are quite often ineffective for instant fixation and/or for long- lasting bonding strength, especially under mechanical stresses.

Furthermore, in the context hereof, in which the elements to be fixed are made of different materials, an assessment is required on the compatibility of the fixation system and method with the materials of the elements to be fixed. This namely includes an assessment of the type of metal that forms the metal elements, any protective coating in use, e.g. the type of paint, if any, whether or not a zinc coating is provided, etc. and an assessment of the materials of the plastic elements, which may be highly heterogeneous, each with different peculiarities.

Therefore, prior art solutions still suffer from drawbacks, also in terms of the aesthetic quality of the fixation, namely in the case of gluing, which often requires a “handcrafting” approach, with more extensive, possibly repeated handling of the details, the requirement of a larger working space, quite long process times due to multiple successive positioning and bonding steps, which often require the use of tools such as grippers or clamps for gluing, without excluding the risk of displacements.

Last but not least, gluing is always affected by the risk of later offsets caused by the viscosity of the glue and the weight force on the elements.

SUMMARY OF THE INVENTION

In view of the foregoing, the purpose of the present invention is to provide a system and a method for fixing elements or parts of elements made of different materials that can overcome the drawbacks of prior art systems and methods.

Specifically, as a part of this purpose, one object of the present invention is to provide a system for fixing elements or parts of elements made of different materials that is inexpensive, easy to manufacture and quick to use, has industrial applicability and can achieve better aesthetic results as compared with the systems of the prior art. A further object of the present invention is to provide a method for fixing elements or parts of elements made of different materials that is inexpensive and quick to implement, affords effective fixation both in terms of strength and stability of the fixation and in terms of aesthetic impact.

The above purpose and these and other objects are fulfilled by a system for fixing elements or parts of elements made of different materials as defined in claim 1 and by a method for fixing elements or parts of elements made of different materials as defined in claim 8.

Further characteristics of the system and method for fixing elements or parts of elements made of different materials of the present invention will form the subject of the dependent claims.

LIST OF FIGURES

Further characteristics and advantages will be better explained by the following description of a preferred embodiment of the present invention, which will be given by way of example and without limitation hereinbelow with the help of the accompanying drawings, in which:

Figure 1 shows a perspective view of a fixing element that is part of the fixation system of the present invention;

Figure 2 shows a sectional view of the fixing element of Figure 1;

Figure 3 shows a cross-sectional view of a fixing element of the present invention according to a second embodiment;

Figure 4 shows a view of an assembly step with the fixation system of the present invention;

Figure 5 shows an additional assembly step with the system of the present invention in which a plurality of metal elements are fixed by means of a plurality of fixing elements to a plastic element.

DETAILED DESCRIPTION OF THE INVENTION

The fixation system of the present invention, for fixing elements or parts of elements 20, 30 made of different materials, namely for fixing an element made of a plastic material 30 to an element made of a metal material 20, comprises a fixing element 10 having a T- shaped cross section, as namely shown by way of example in Figures 1 and 2.

More in detail, said fixing element 10 advantageously comprises a larger head portion 11, connected to a smaller shank 12.

Preferably, the position of the head portion 11 is symmetrical about the shank 12, the fixing element 10 being symmetrical on a sectional plane that passes through the center axis.

In the embodiment as shown in the accompanying figures, said fixing element 10 is preferably configured with a disk-shaped head portion 11, connected to a cylindrical shank 12 , therefore the symmetry of the fixing element 10 is a cylindrical symmetry about a vertical center axis.

In this preferred embodiment, said disk-shaped head portion 11 will have a first diameter dl greater than the second diameter d2 of the cylindrical shank 12.

Said fixing element 10 is advantageously made of a plastic material, and will be more preferably made of the same material as the plastic element 30 to be fixed to the metal element 20. Preferably, at least the shank 12 of said fixing element 10 will be made of the same plastic material as the plastic element 30.

This will address any compatibility issues of the different materials.

In order to carry out the fixation process, the metal parts 20 to be fixed are generally formed with holes 21 for insertion of fixing elements, otherwise such holes will be formed ad hoc.

With the fixation system and method of the present invention, the shanks 12 of said fixing elements 10 are inserted into said holes 21 formed in said metal part 20. Advantageously, said shank 12 of said fixing element 10 will have a length, i.e. an axial extent equal to or slightly less than the thickness of the metal sheet. Similarly, said head portion 11 may advantageously have varying shapes, thicknesses, and dimensions as appropriate according to the applications. In the preferred disk configuration, said head portion 11 may have varying diameters dl and thicknesses, to avoid interference and provide the mechanical conditions for a fixation strength surface.

Advantageously, the fixation system and method for fixing elements 20, 30 or parts of elements made of different materials according to the present invention also affords the possibility of joining together multiple fixing elements 10 at said head portion 11 of each element, to provide a multiple fixing element 10' comprising a single extended head portion 11’ conforming in shape to the profile of the elements 20, 30 to be connected, from which a plurality of shanks 12 extends, for quick optimized positioning and instant fixation of a plurality of shanks 12 within a corresponding plurality of holes 21 formed in said metal elements 20.

Once said fixation elements 10, 10' are positioned with their respective shanks 12 within the fixation holes 21 of said metal element 20, and once said metal element 20 is positioned close to the plastic element 30 to which it has to be fixed in the final fixed position, the fixation method of the present invention provides fusion welding of the shanks 12 of said fixing elements 10, 10' to the plastic element 30. Since said fixing elements 10, 10', or at least the shanks 12 of said fixing elements, are made of the same material as the plastic element 30 with which it has to be connected, such welding is optimal.

That is, fusion welding of the plastic parts of the fixing element 10, 10' and of the plastic element 30, preferably obtained by application of ultrasound, affords instant mechanical fastening of the metal element 20, the plastic element 30 and said fixing element 10, 10' in the proper predetermined position, thereby avoiding the extension of process times caused by the need to wait for adhesive curing in conventional methods.

Advantageously, the fixation method of the present invention, which uses said fixing elements 10, 10', may further comprise a step of bonding the elements 20, 30 made of different materials using glues or mastics, to achieve a greater overall fixation strength and/or to fill any gaps that may remain between said elements 20, 30 as a result of complex profiles and/or surfaces that are not perfectly smooth.

The system and method for fixing elements or parts of elements 20, 30 made of different materials according to the present invention provides a novel, cost-effective and industrially applicable solution to the problems of prior art systems, while affording improved fixation, also in aesthetic terms, as compared with prior art gluing solutions.

That is, the system and method for fixing elements or parts of elements 20, 30 made of different materials according to the present invention, avoids the need for repeated handling of the components, and hence the need for a larger working space, and reduces fixation times, by no longer requiring the use of temporary locking means, such as grippers and clamps, for gluing, which not exclude the risk of undesired displacements or offsets when gluing and during glue curing due to the viscosity of the glue and the weight of the components.

It will be appreciated from the foregoing that the system and method for fixing elements or parts of elements 20, 30 made of different materials according to the present invention fulfill the intended purpose and objects.

The system and the method of the present invention are also susceptible of changes and variations within the scope of the invention as defined in the appended claims.