PANEL TO A SUPPORTING STRUCTURE

Technical field

This invention relates to a universal fastening apparatus for connecting a panel to a supporting structure .

More specifically, the invention fits into the sectors relating to fastening, prefabricated, self-locking devices which have plugs insertable into the supporting structure and screws which engage in the plugs and which clamp them to the supporting structure by means of a forced radial expansion of some of their component parts .

Background art

That general fastening context also includes in particular some techniques relating to fastening panels for covering building structures , for example for forming plasterboard covering surfaces with enhanced surface uniformity and finish; or for increasing the thermal insulation of traditional building structures by covering them with and fastening to them thermal insulation panels , as is the case when making insulated structures currently called "thermal cladding" .

In the latter case, and in many other similar situations , work often involves very thick insulation panels , the thicknesses sometimes even reaching ten centimetres or more .

Moreover, just as frequently, work involves covering thicknesses which are not only considerable in terms of thickness size, but which may also vary from one wall of the building to another, as happens in building structures , where due to the different orientations of the walls , higher thicknesses are essential for insulating walls which disperse the most energy, whilst lower thicknesses may be required for insulating walls more favourably exposed relative to the sun .

Consequently, to deal with situations of this type and with such variability a large number of fastening devices must be kept available which have variable dimensions according to quite large geometric ranges and are always suitable for the effective extent of the thicknesses of the panels to be fastened .

Management of such fastening devices therefore requires shrewd organisational care, both as regard the supply of the various fastening devices necessary, and in terms of their practical installation .

Moreover, it should also be noticed that in such application contexts such fastening devices also disadvantageously have a relatively high intrinsic unit cost because of their large intrinsic dimensions .

Indeed, since they have relatively large dimensions and are made of plastic material formed by inj ection moulding, it being possible to make few of them together in a mould with standard dimensions , the high cost of the moulding equipment negatively impacts the unit cost of the individual apparatuses since the cost of the equipment necessary to make them takes a very long time to amortise . Consequently, if the size ranges of those fastening devices to be kept available are also many types , the intrinsic cost of such devices has a considerable effect on the cost of fitting those same wall coverings . Disclosure of invention

The aim of this invention is to overcome those disadvantages , by making available a universal fastening device which, on its own, can easily and quickly be adaptable to be able to deal with many different practical situations , that is to say, which can be used for fastening panels having ranges of thicknesses which are variable and/or even very different from each other .

Accordingly, the invention achieves that result with a fastening device whose technical features are defined in the appended claims .

Brief description of drawings

Further technical features and advantages of the invention will become apparent in the following description of an example, non-limiting embodiment of the invention, with reference to the figures of the accompanying drawings in which :

- Figure 1 is an assembly view of the fastening apparatus according to the invention illustrated in an example, nonlimiting first embodiment;

- Figure 2 is an exploded view of the apparatus of Figure 1 ;

- Figures 3 and 4 are detailed views of several details of the invention of the preceding Figures 1 and 2 ;

- Figure 5 is an assembly view of a second embodiment of the invention;

- Figures 6 and 7 are exploded perspective views of several parts of the apparatus of the preceding figures shown with some parts cut away to better illustrate others .

Preferred embodiments of the invention With reference to the figures of the accompanying drawings in Figure 1 the numeral 1 denotes in its entirety a fastening apparatus for connecting a generic panel 2 to a supporting structure 3 which is also generic and, as such, they are shown together in an extremely simplified way . Preferably, but without limiting the scope of the invention, the panel 2 may for example be a very thick panel , made of thermal insulating material .

The supporting structure 3 may, for example, be a wall of a building made of conventional materials and intended to be clad and/or covered by the panel 2 .

The device 1 comprises a screw 4 ( see Figure 2 ) and a plug 5 which are elongate relative to a longitudinal line 6 . The plug 5 is provided with a root 7 housable in a receiving seat 8 of the supporting structure 3 , in which (and in the known way) the root 7 is immobilisable as a result of a radial expansion, opening out and interfering with the seat 8 itself , imparted by the forward movement of the screw 4 along the longitudinal line 6 and inside the root 7 .

Figure 1 , and more particularly Figures 2 and 3 , show how the plug 5 is provided with an elongate shank 9 , placed so that it is a continuation of said root 7 , monolithic with it and j utting from a collar 24 interposed between shank 9 and root 7 .

The shank 9 is shaped to abut, along the longitudinal line 6 , and during apparatus fastening, a head 4t of the screw 4 which, preferably (as shown in Figure 6 ) has a length substantially equal to the sum of the lengths of said shank 9 and of said root 7 . The plug 5 is also provided with a unit 10 for hooking and retaining the panel 2 abutting the supporting structure 3 .

Placed between the elongate shank 9 and the hooking unit 10 , the plug 5 features the presence of telescopic adjusting means 11 for its length, which are adj ustable according to the axial line 6 depending on the effective thickness of the panel 2 which is interposed between the supporting structure 3 , on one side, and the hooking unit 10 placed on the other side .

According to a first embodiment, identified in Figures 1 to 3 , the telescopic adj usting means 11 are devised to be unidirectionally adj ustable in the direction of the axial line 6 directed towards the supporting structure 3 , said adjustment being inhibited in the opposite direction, of movement of said panel 2 away from said supporting structure 3 .

More specifically, the figures show how that embodiment of the telescopic adj usting means 11 comprises a ratchet gear with teeth 12 and a rack 13 shaped to match each other which are borne, in such a way that they are exchangeable and without distinction and reversible with each other, by a stretch 14 of the elongate shank 9 and by a tubular body 15 shaped to match it supported by the unit 10 for hooking and retaining the panel 2 .

As Figure 2 clearly shows , the teeth 12 consist of a series of circumferential stretches j utting cantilever-style from the shank 9 ; whilst the rack 13 consists of a series of slits , shaped to match the teeth, made through the tubular body 15 of the hooking unit 10 . The teeth 12 and the slits forming the rack 13 are shaped in such a way as to engage with an elastic snap-in action : without coming undone in one direction along the longitudinal line 6 ; in contrast, leaving the respective parts of the ratchet gear free to slide relative to each other in the opposite direction .

Comparing Figures 2 and 3 shows how the plug 5 comprises anti-rotation constraining means 20 interposed between the shank 9 and the tubular body 15 , designed to inhibit the relative freedom of rotation about the longitudinal line 6 of the shank 9 and of the tubular body 15 .

Those constraining means 20 comprise, in particular, a groove 21 and a proj ection 22 which are interposed between the shank 9 and the tubular body 15 , are elongate parallel to the longitudinal line 6 and shaped to match each other with regard to their mutual radial interpenetration, in the figures being shown as substantially parallelepipeds . The presence of the groove 21 and of the proj ection 22 forms a guide which, on one hand, ensures regular engagement of the teeth 12 with the rack 13 and, on the other hand, allows an immediate and simple adj ustment of the length of the plug 5 depending on the effective thickness of the panel 2 .

Indeed, this adj ustment can be achieved simply by pressing with one hand against the hooking unit 10 and applying controlled thrust directed towards the supporting structure 3 for the panel 2 .

In contrast, Figure 4 shows an alternative embodiment of the apparatus 1 (also by way of example and without limiting the scope of the invention) , in which the adjusting means 11 are adjustable in both directions along the longitudinal line 6 .

Figures 5 and 6 show how in that case, said adj usting means 11 consist of a thread 23 with male screw 23a and female screw 23b shaped to match each other - which are borne, in such a way that they are exchangeable with each other and without distinction - one by a stretch 14 of the elongate shank 9 and the other by a tubular body 15 shaped to match it supported by the unit 10 for hooking and retaining the panel 2 , or vice versa .

Regarding the hooking unit 10 , the figures show how it is provided with a disc-shaped head 16 supported by the end of the tubular body 15 which is distal from the adj usting means 11 .

Finally, Figure 7 shows how the plug 5 may comprise means 17 for driving the rotation of the tubular body 15 about the longitudinal line 6 , which comprise engaging seats 17a for a tool which are made through the disc-shaped head 16 . A very simple tool (not shown in the drawings ) provided with two due pegs insertable in two seats 17a of the discshaped head 16 and bilateral with respect to the line 6 , allows activation of the telescopic adj usting means 11 for performing a precision adj ustment of the length of the plug 5 depending on the effective thickness of the panel 2 .

Returning to Figures 4 and 5 it can be seen how the hooking unit 10 , with disc-shaped head 16 , may also bear a cylindrical crown gear 18 , with saw teeth 19 which, when the head 16 rotates about the longitudinal line 6 , is able to cut into the panel 2 a lowered seat 8 , in which the head 16 is at least partly recessable in the thickness of the panel 2 .

Such a solution can be usefully applied when the aim is to completely conceal the plug 5 from view from the outside of a wall covering; or when it is feared that the metal screw 4 contained inside the apparatus 1 might form a preferential heat exchange vector between the environments otherwise separated by the insulating panel 2 (a so called "thermal bridge" ) .

In that case, as it rotates , the crown gear 18 - driven by the above-mentioned tool - creates a sort of "core boring" effect in which the part of the thermal insulating material below the head 16 is cut off and separated from the rest of the material of which the panel 2 consists which in contrast surrounds the head 16 itself .

As screwing of the head 16 continues , under the compression force applied by head 16, the core of insulating material is compressed and compacted .

As a result of that, in the insulating material a lowered seat is automatically created in which the head 16 is sunk inside the undeformed thickness of the material of the panel 2 .

Where the material has been compacted it is therefore possible to then cover the head 16 with the j uxtaposition of a cap of insulating material which, by restoring the surface continuity of the thermal insulation completely shields the screw 4 inside the insulating material , totally inhibiting its ability to conduct heat flow through the panel 2 . The invention fulfils the stated aims , partly thanks to the fact that it has a relatively simple structure, is reliable in use and is inexpensive .