This invention refers to a joint complete with peripheral fasteners for frames intended for the support of sheets, panels and similar items. It is well-known that, in order to move objects that are large in size and rather bulky, although not that wide and with limited weight, like for instance paintings, prints, panels, sheets and similar items, special protective packages are required, along with specific storage arrangements and suitable shock-proof handling precautions, especially if shipping is carried out by air or by sea. All the above entails considerable financial investments.

It is also well-known that the current panel structures, designed for example to hold works of art, for the realization of walls for tradeshow stands, boxes, partition walls, prefabricated constructions for temporary use in building yards and the like, in addition to being expensive in themselves, also include connection, coupling and assembly/disassembly devices that require special additional tooling, specific precautions, long execution times and, consequently, high costs related to the structures themselves as well as to the workforce. The purpose of this invention is to eliminate, or at least to minimize the aforementioned inconveniences.

The invention solves the problem with a joint comprising peripheral fasteners, and characterized by the fact that it is made up of two

identical annular disc half-joints, which in turn include, in diametrically opposed positions: two extensions, at least two peripheral notches and just as many complementary radial teeth staggered in parallel; these annular disc semi-joints, adjusted in symmetrical opposition with the passage of said teeth through said notches, beyond the thickness of the same discs, and with a partial rotation, hook up firmly to each other and form, with said extensions, an X-shaped joint whose arms, made of the same extensions, can be adjusted as desired towards the corners or the edges of the quadrangular panels and sheets to be supported, and where on said extensions tubular pipes engage, equipped with end fasteners for the aforementioned sheets and/or panels or similar. The central holes of these coupled annular disc half-joints constitute the hookup point of the X-shaped joint to a fixed support, which can be fastened to uprights or walls, that includes an intermediate saddle in flexible elastic material with a high friction coefficient, with a rounded outer surface whose diameter is equal to the central hole of said X-shaped joint and with a central compartment comprising a bottom opening with inclined sides and an eccentric top extension that interpositions itself by pressure between the same central hole of, said X-shaped joint and the stem, with a partial wedge-shaped profile in the bottom section, of said fixed support.

The advantages offered by this joint consist in the fact that the components making up the joint and its fasteners can be assembled and adjusted when needed so that, for the procurement, freight and

shipment, they can be included in inexpensive and space-saving packages; likewise, special types of panels and/or sheets can be rolled up and protected in space-saving packing, also simple and economic, for freight and shipping; the assembled joint, with possible suitable extensions, takes on an X-shaped configuration with adjustable and extendable arms which allow it to be used for any flat and hung panel and/or sheet, to be displayed or set up; for applications on very wide panels or sheets, either in length and/or height, the joint, associated with the respective fasteners, can be sequentially combined with other identical joints; at the end of the X-shaped adjustable arms of the joint, with or without additional extensions, various types of fasteners are foreseen, both for flexible panels and/or sheets that can be rolled up and for rigid ones; the hookup devices intended for joint support can be applied to the walls, uprights or other external supports; the supports, consisting of the joints and of the related fasteners according to the invention, are not visible as they are positioned in the rear of the sheets, panels and similar, and they support these items without the need for any kind of frame. The invention is described in detail below, according to its implementations provided here solely for example purposes and not meant to be limitative, with reference to the enclosed drawings, in which:

Figure 1 represents the overall view of a joint for support frames, with adjustable X-shaped arms, consisting of two identical disc half- joints coupled in opposition and by different peripheral fasteners for

sheets and/or panels, positioned at the outer ends of tubular pipes; the joint is shown from the rear side of the panels or sheets;

Figure 1 b represents the overall view of the same joint as in the previous figure equipped with other end fasteners;

Figure 2 represents the position of the two identical half-joints during the phase of opposite coupling in the center, to form the X-shaped structure with adjustable arms;

Figures 3a, 3b, 3c represent one of said identical disc half-joints, in side, front and opposite view;

Figures 4a, 4b, 4c represent one of said identical disc half-joints, seen from the side and partially sectioned, seen from the front and in cross-section;

Figures 5 a, 5b, 5 c, 5d, 5e represent, respectively, a boss seen in plan view and side view and an end square, in front, side and longitudinal section views, which are coupled together in a first example of peripheral fasteners for sheets and/or panels;

Figures 5f, 5g, 5h, 5i, 51 represent, respectively, a boss seen in plan view and side view and an end square in front, side and plan view, coupled together in a second example with peripheral fasteners for sheets and/or panels;

Figures 6a, 6b, 6c, 6d represent, respectively, an end sleeve seen in plan view coupled to an angle bracket, seen in plan view coupled to a flat bracket and seen in longitudinal section coupled to two different clamping devices , of a third example of peripheral fasteners for sheets and/or panels;

Figures 7a, 7b, 7c, 7d represent, respectively, an end fork in side view, front view and plan view coupled to a different angle bracket and to a different flat bracket;

Figures 8a, 8b represent, respectively, an end fork in side view and in plan view coupled to a boss with related clamping screw;

Figures 9a, 9b, 9c represent, respectively, two end forks coupled to an angle, seen in plan view and in side view, and seen from the side in an aligned coupling;

Figures 10a, 10b, 10c, 1Od represent, respectively, an example of a wall support for the support of the joint for frames, in front view/section and in cross-section, and an intermediate fork made in elastic friction materials in side view and in front view;

Figures 11a, l ib represent, respectively, in cross-section and in partial more enlarged front view, the coaxial introduction phase of a joint on a wall support the type illustrated in figures 7a ÷ 7b;

Figures 12a, 12b represent, respectively, in cross-section and in partial more enlarged front view, the following hookup phase towards the bottom of the same joint as figures 8a, 8b on a wall support the type illustrated in figures 7a ÷ 7b.

In reference to the figures, the joint consists of two identical annular disc half-joints 1 which, in diametrically opposed positions, include: two extensions 2, at least two peripheral notches 3 and just as many complementary radial teeth 4 staggered in parallel.

The annular disc half-joints 1, adjusted in symmetrical opposition, with teeth 4 passed through the notches 3 beyond the thickness of the

same annular half-joints and partially rotated 40, hook up firmly to each other. In this way they form, along with the extensions 2, an X- shaped joint 5 whose arms, made of the same opposite extensions 2, can be adjusted as desired towards the corners or the edges of square- shaped panels or sheets to be supported.

The extensions 2 are configured so as to constitute interlocking devices for tubular single pipes 7, or tubular multiple pipes 7' interlocked in sequence, or telescopic pipes 7" with locking ring nuts 50, intended to take on the desired length required to unite the central joint 5, which is the element through which everything can be hung to the wall, to connection points 8, basically arranged along the semi- diagonals and near the corners 9, or on the opposite sides of a panel or of a sheet 6.

For this reason, some fasteners 10, 10' 10" are interlocked on the outer ends of the tubular pipes 7, 7' or 7". In a first solution (figures 5a÷5d), the fasteners 10 are made up of squares 11 and bosses 14 which are coupled together by means of a threaded orthogonal pin 13, arranged on the squares 11 and by a corresponding threaded hole arranged on the bosses 14; alternatively, the threaded hole can be ,arranged on the squares and the threaded pin on the bosses 14; in yet another way, (figures 5f÷51) the square 11 ' includes a fork-shaped seat in which a knurled ring nut 13' rotates, integral with threaded pin 13, which allows the manual tightening of the boss 14, without using tools; in yet another way the coupling, in one way or in the opposite

way, does not have to be threaded but is instead obtained with pins and holes engaged by a more or less strong pressure. In any case, the squares 11 include a compartment 12 in which the outer parts of said tubular pipes 7, 7' interlock. The sheets and panels 6 are supplied with passing holes 15, corresponding to connection points 8, in which said pins 13 are inserted; after that, the sheets or panels are locked in position by means of said bosses 14. In another solution (figures 6a, 6b, 6c), the fasteners 10', also supplied with compartment 12 interlocked on the outer parts of said tubular pipes 7, 7', are made up of sleeves 16 that include the extensions 17 equipped with orthogonal pins 18. On the pins 18, U-shaped brackets 19 are centered, which can be adjusted in the most suitable manner around the same pins to firmly grasp the edges 20 of panels 6, or similar, in a vertical, horizontal or inclined direction; U-shaped square brackets, 19' on the other hand are used to obtain an angular grasp. The locking in position of brackets 19, 19' is obtained by means of threaded dowels 21 that screw into the same threaded holes 22 in which pins 18 are centered and which adhere against the top part of the same pins, recalling said brackets against the panels 6 to be supported. Alternatively, the sleeves 16' (figure 6d) include tongues 17' with passing holes through which threaded pin 21 ' passes, coupled to a complementary threaded hole drilled in said U-shaped brackets 19, 19'. By rotating threaded pin 21' the brackets can be moved closer or farther apart to grasp the edges 20 of the panels 6, or similar, in a vertical, horizontal, inclined or angular direction.

In case multiple tubular pipes 7' are used, combined in sequence, the coupling can be in any known way: by fixed interlocking with complementary male-female shapes; by means of retention pins to be coupled in holes arranged along the male or female part of the tubular pipes; by means of an elastic retention device, like an internal spring, which stretches the coupled tubular pipes facilitating their tension and compensating for any differences between the connection points of sheets or panels 6 and the fasteners 10, 10'.

In an additional version, (figures 7a÷7d) the fasteners 10" consist of forks 16" comprising a central pin 51 with thread 52 that couples with a threaded hole on one of the tongues of said U-shaped brackets 19, 19', either shaped or straight. The central pin 51 of forks 16" includes an outer key 53 which, when rotated manually, brings closer or farther apart the edges 54 of the forks from the edges 55 of the brackets 19, 19' , constraining or freeing parts of the sheets or panels 6 positioned between them.

In figures 8a and 8b, the central pin 51, with key 53, includes a threaded outer end 56 that couples with a boss 14. The forks 16" include a rear extension 2' intended for the internal interlocking couplings in the ends of the aforementioned tubular pipes 7, 7', 7". These rear extensions 2' are misaligned, compared the forks, in order to allow proper alignment in case of direct coupling of the same forks, one with the other frontally. Through the central hole 23, made up by the coupling of the circular half-joints 1, the central X-shaped body 5 of the joint, associated to a

panel or sheet 6, is hung to a fixed support 24 which can be fastened to a wall, to uprights or to other vertical supports 25.

The central hole 23 of the joint rests and hooks up with stem 26 of fixed support 24, with the interposition of a saddle 27 in elastic material with high friction coefficient.

The fixed support 24 is fastened to said walls, uprights or other vertical support in general 25, by means of expansion screws, bolts or other; in the represented case, the fixed support 24 includes, for this purpose, a central passing hole 28.

The stem 26 to which the X-shaped joint 5 hooks up is, preferably but not limitedly, eccentric with respect to the resting surface of the fixed support 24' on said walls, uprights or vertical supports 25, for the purpose of guaranteeing better weight distribution.

The saddle 27, made in elastic material, includes: an outer rounded surface 29 and a central compartment 30 which is formed by a bottom opening 31 with inclined sides 32 and an upper eccentric extension

33; the material's flexibility allows the application by pressure of the saddle astride the stem 26, with its inclined sides 32 arranged so that they adhere to the complementary inclined lateral profiles 32' of the wedge-shaped lower part 26' of the stem itself.

In this arrangement, the central annular compartment 23 of joint 5, which features a diameter that is basically equal, minus a coupling tolerance, to said rounded surface 23, introduces itself horizontally, according to arrow 34 on the outer rounded surface 29 of the saddle

27.

By means of a pressure, which may simply depend on the weight of the object to be hung, the joint 5 moves downward according to arrow 35, and the saddle 27, trapped in the central annular compartment 23, is forced to move in that direction, losing its shape until it arranges its eccentric extension 33 resting on stem 26 of the support 24, while its inclined sides 32 are forced to slide and widen along the complementary inclined side profiles 32' of the bottom part with a wedge-shape profile 26' of the stem 26. Depending on the resulting tight friction adherence, due to the necking down elastic deformation undergone by the saddle 27, engaged between the stem 26, 26' and the rounded seat 29, the joint stays perfectly fastened to the fixed support 24, supporting the associated panel or sheet 6 with accuracy and without any danger of detachment or oscillations. In case the supported sheets or panels are very long, in terms of height, or very high, in terms of width, a side-by-side coupling is possible horizontally or vertically by means of, for example, supplementary plates 36 or, better yet, by means of identical forks 16" engaged and connected to each other by the reciprocal side-by- side positioning of their edges 55 and the locking with a central pin 51 (figures 9 a, b, c); for this solution the rear extensions 2' are arranged in a misaligned fashion in order to compensate from the overall dimensions of the side by side positioning resulting from the thickness of said edges 55. These couplings make it possible to achieve inclined (figures 9 a, b) or straight junctions (fig. 9 c).

Thanks to the arrangement of the constraints on four equidistant points of the X-shaped structure 5 of the joint, basically arranged and lined up at the end of the diagonals, the quadrangular configurations of the sheets and/or panels 6 remain stretched and in a self-bearing position.

In any case and for particularly delicate applications, one of the discs 1 can include a threaded passing hole in which a dowel 37 is coupled that connects to the other disc 1 after the proper and pre-established alignment of the coupling of the half-joints. Similar retention dowels 37' can also be applied to the arms 2 and to the fasteners 10, 10' at the interlocking couplings with the end tubular pipes 7 and/or 7'.