BACKGROUND OF THE INVENTION The present invention relates to an improved mechanical flush-mounted device, for application to perforated tiles.

As is known, great difficulties are at present encountered in applying mechanical flush- mounted devices to walls made of perforated tiles and the like, since the plug which is radially expanded cannot be properly and firmly engaged in the perforated tile.

Thus, prior flush-mounted mechanical devices, in some cases, can be unsatisfactorily clamped to a perforated tile construction.

In order to overcome the above mentioned drawbacks, several types of expandible plugs have already been designed, having very different constructions, such as, for example, finned resilient expanding plugs which, however, do not allow to obtain a satisfactory distribution of the applied efforts and, moreover, are of great constructional complexity and cost.

Other prior solutions, including the provision of differentiated-surface expanding plugs, have not been found satisfactory, since they could not provide a desired expanding pattern.

SUMMARY OF THE INVENTION Accordingly, the aim of the present

invention is to overcome the above mentioned drawbacks, by providing an improved mechanical flush- mounted device, specifically designed for application to perforated tiles, which can be fixed or clamped in an optimum manner, by conventional clamping operations providing a rotation of the device body, so as to provide the desired expansion and consequent locking of the device.

Within the scope of the above mentioned aim, a main object of the present invention is to provide such a mechanical device in which it is possible to obtain differentiated locking regions, adapted to be actuated independently from one another and which, consequently, are suitable to provide a very good clamping function.

Another object of the present invention is to provide such a mechanical device which, owing to its specifically designed constructional characteristics, is very reliable and safe in operation.

Yet another object of the present invention is to provide such an improved mechanical flush- mounted device which can be easily made starting from easily commercially available elements and materials.

According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by an improved mechanical flush-mounted device, for application to perforated tiles, characterized in that said device comprises a rod having an outer connecting end and defining a first threaded portion having a greater

diameter and a second threaded portion having a smaller diameter, arranged at an inner end of said rod, said first and second threaded portion including, respectively, a first and second expandible plugs which can be independently radially expanded, by axial pressing means engaging with said threaded portions.

BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred, though not exclusive, embodiment of an improved mechanical flush-mounted device, specifically designed for application to perforated tiles, and which is illustrated, by way of an indicative, but not limitative, example, in the accompanying drawings, where: Figure 1 is an exploded perspective view illustrating the mechanical device according to the present invention; Figure 2 is a further perspective view illustrating the mechanical device according to the invention; Figure 3 is a further perspective view illustrating said mechanical device engaged in a perforated tile element; and Figure 4 is a cross-sectional view illustrating the procedure for radially expanding and clamping or fixing the mechanical device according to the present invention on a perforated tile element.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the number references of the above mentioned figures, the improved mechanical flush-mounted device, specifically designed for application to perforated tiles and the like, according to the present invention, and which has been generally indicated by the reference number 1, comprises a body 2 having an outer coupling or connecting end which can comprise an hexagonal rod 3, or, optionally, a screw element having a recessed hexagon cylindric head ; or other like elements.

The body 1 defines a rod 4, comprising a first threaded portion 5, having a larger diameter, and a second threaded portion 6, having a smaller diameter.

At the transition region between the outer connecting end and first threaded portion 5, a first washer 10 is arranged, and a second washer 11 is arranged between the first and second threaded portions, said second washer 11 being prevented from displacing since the larger diameter of the first threaded portion 5 will prevent said washer from sliding.

On the threaded portion 5 is engaged a first expanding plug 20, which can be radially expanded by a first cylindric nut 21, engaging with the threaded portion 5.

On the second threaded portion 6 is arranged a second expanding plug 22, abutting against the second washer 11 and being axially pressed by a second cylindric nut 23 engaging with the second

threaded portion 6.

The latter is arranged at the inner end of the mechanical device according to the invention.

By using the device of the invention, upon having engaged the rod 4 in the hole provided therefor, by conventionally turning said rod, the plugs 20 and 22 are axially pressed, in an independent manner, under the action of the first cylindric nut 21 and second cylindric nut 23.

Thus, as stated, the expanding plugs 20, and 22 are radially expanded independently from one another.

With the expanding plug arranged at a set given distance, it is possible to operate on several walls of a same perforated tile 10 or any other elements constituting a fixed construction, to which the subject mechanical device must be clamped.

From the above disclosure it should be apparent that the invention fully achieves the intended aim and objects.

In particular, the invention provides a mechanical flush-mounted device including a double expanding body, allowing to independently expand two expanding plugs, since two threaded portions having different diameters are provided.

The washer 11 operates as a separating and abutment element for the second expanding plug 22, which can be expanded independently from the radial expansion of the first expanding plug 20.

The invention, as disclosed, is susceptible to several modifications and variations, all of which will come within the scope of the invention.

Moreover, all the constructional details can be replaced by other technically equivalent elements.

In practicing the invention, the used materials, and the contingent size and shapes can be any, depending on requirements.