The present invention relates to a joining system between a supporting plane, for example a table top, and a tubular element, for example a leg for said table .

Various joining systems are known between a supporting plane and a tubular element consisting of a first male part and a second female part suitable for being intercoupled, and. fixing means acting betwee said two male-female parts, so as to make the coupling stable .

A joining system of the type briefly described above is the obj ect of patent EP1279353 which describes a joining system according to the preamble of claim 1.

One of the requirements that must be satisfied by the above-mentioned joining systems is that the fixing means between the male and female parts must not only be easily accessible, but also concealed from sight, even in the presence of transparent supporting surfaces, such as glass or crystal tables.

The general objective of the present invention is therefore to satisfy said requirement of non-visibility of the fixing means, for example grub screws (headless screws), between said male and female parts forming the joining system.

This objective is achieved by a joining system as described in the enclosed claim 1 and sub-claims.

'The structural and functional characteristics of the present invention, and its advantages with respect to the known art, can be clearly understood from the following description, referring to the enclosed drawings, which illustrate various embodiment examples of the invention itself,

I the drawings:

figure 1 is an exploded vertical sectional view, taken according to the line I-I of figure 2 , illustrating a first embodiment of a joining system according to the invention;

- figure 2 is a plan view from below of the joining system of figure 1 ;

figure 3 is a vertical sectional view of the joining system of figure 1, assembled;

figure 4 is an exploded vertical sectional view, taken according to the line IV-IV of figure 6, illustrating a second embodiment of a joining system according to the invention;

figure 5 is an exploded perspective view of the joining system of figure 4;

- figure 6 is a plan view from below of the joining system of figure 4 ;

figure 7 is a vertical sectional view of the joining system of figure 4, assembled;

figures 8, 9 and 10 are exploded perspective views showing three different embodiments of the male part of the joining system according to the invention.

With reference first of all to figures 1-3 of the drawings, the joining system object of the present invention is indicated as a whole with 10 and has the function of stabl connecting ^' a. supporting plane 11, for example a table, to a tubular element 12, for example a cylindrical leg or other section of said table.

The joining system 10 consists of a male- female joint comprising a first male part 13 and a second female part 14.

'The male part 13 is fixed at one end (top) of the tubular element 12, whereas the female part 14 is fixed below the plane 11, preferably, but not necessarily, directly against its lower surface 15.

The fixincj of said male part 13 to the tubular element 12 and said female part to the surface 15 can be effected by any means suitable for the purpose, for example UV glues, or mechanical systems of the known type (expansion, screws, etc.) . More specifically, said male part 13 consists, in the example of figures 1-3, of a discoidal plate 16, having an adequate thickness h, fixed to the top of the tubular element 12 by means of a shank 17. The plate 16 has a grooved annular edge 18, with a "V"-shaped section, as clearly illustrated in the drawings, thus having tilted surfaces VI and V2.

The female part 14 consists of a base 19 fixed directly to the lower surface 15 of the plane 11 and is provided in an annular collar 20 having a suitable depth P, equal to the thickness h of the plate 16.

Characteristically, a plurality of grub screws 21 (headless screws) is housed in said collar 20, in the example illustrated four in number arranged at 90° with respect to each other.

As can be clearly seen in figures 2 and 3 of the drawings, said grub screws 21 are each housed within a threaded pass-through hole 24, with an axis X tilted with respect to the plane 11.

The inclination of said axis X is such that the inlet of the hole 24 (outside the collar 20) is situated on the horizontal edge 25 of the collar 20 itself, parallel to the plane 11, whereas the outlet, of said hole 24 is inside the collar 20, in correspondence with its vertical wall 26 perpendicular to the plane 11.

In other words, said grub screws 21 are contained inside the collar 20 and are tilted with respect to the plane 11 so as to have an actuation side L arranged beneath the collar 20 itself, in a position concealed from sight.

In the example illustrated, the axis X forms an angle of 90° with the upper surface VI of the groove 18.

In this way the grub screws 21 are concealed from sight - above and from, the side -, even in the presence of a transparent, plane 11.

According to the actual needs, said angle can also be different from 90°.

The functioning of the joining system according to the invention is evident from what is described above with reference to the figures, and is briefly the following .

With the grub screws 21 in the position of figure 1, partially extracted from the horizontal edge 25 of the collar 20, the male part 13 is inserted, with movement in the direction of the arrow F, inside the complementary female part 14; the grub screws 21 are subsequently firmly screwed, by means of a screwdriver (not shown), with their flat tip 27, opposite the maneuvering head 28, inside the V-shaped, groove 18 of the plate 16, so as to be abutted against the tilted surface VI of the same groove 18, by pushing the outer upper end surface SI of the male part 13 to be firmly abutted against the inner surface S2 of the base 19 of the female part 14.

In this way, the tubular element 12 is stably connected to the plane 11 with, a joining system completely concealed from sight. The grub screws 21 are, in fact, invisible, even in the case of a transparent top 11, completely from above and from the side, whereas the inlet of the hole 24, easily accessible, can be covered by an aesthetic cap. Again for aesthetic purposes, the female part 14 can naturally also be made of materials with high-quality finishes .

Figures 4-7 show ^" a second possible embodiment of the joining system according to the invention, wherein the same components are indicated with the same reference numbers, whereas equivalent components have the same references increased by 100.

In this embodiment, a tubular element 112 is provided having a rectangular or square cross-section, together with a collar 120 with a vertical annular inner wall 126 and. a square outer perimetric edge 129. As can be clearly seen in Figure 6, four grub screws 21 are housed in said edge 129, arranged in correspondence with the vertices of the square.

The functioning of this embodiment is identical to that of the previous embodiment described with reference to Figures 1-3.

On screwing the grub screws 21, the fiat end 27 of the same pushes against the complementary surface area VI (corresponding) of the groove 18, thus defining the orientation of the tubular element 112 with, respect to the female part 114 of the joint, and the surface SI is tightened against the surface S2, thus making ^' the coupling of the male part 113 and female part 114 stable, hence the coupling of the tubular element 112 with the plane 11.

Whereas in the case of tubular elements with a rectangular or square section (or others, for example triangular) , for a correct automatic orientation between the components, the tip of the grub screws 21 must necessarily be flat, in the case of cylindrical tubular elements (with a circular section) , the tip of the grub screws 21 can also be spherical.

Figures 8-10 are exploded perspective views illustrating three non-limiting examples of fixing systems of the male part 113 to the top of the tubular element 112, said systems naturally also being valid for the cylindrical tubular element 12 previously described .

'The embodiment of Figure 8 provides for the insertion of the shank 117 at the top of the tubular element 112 and a simple gluing, by means of adhesives of the type well known to skilled persons in the field, of the outer surface of the shank 117 to the inner surface of the tubular element 112.

The embodiment of Figure 9 provides for the fixing of the male part 213 of the joint directly to the tubular element 212, without the aid of a shank .

As can be clearly seen from the drawing, in fact, the male part 213 is fixed to the top of the tubular element 212 by means of a screw 229, which is screwed into a threaded section 230 of a tube 231, which extends axiallv from the base to the top of the element 212 itself.

In this embodiment, the components substantially equivalent to those of the first embodiment have the same reference numbers increased by 200.

The embodiment of Figure 10 provides for the use of an expanding shank 317 clamped against the inner wail of the tubular element 312 by means of a maneuvering screw 332, which is screwed into an expanding element 333 which acts on the shank 317 expanding it radially outwardly, so as to tighten it firmly against the inner surface of the tubular element 312.

In this embodiment, the components substantially equivalent to those of the first embodiment have the same reference numbers increased by 300.

The objective mentioned in the preamble of the descri t ion has therefore been achieved .

The protection scope of the present invention is defined by the enclosed claims.