Background Art The invention is applicable particularly but not exclusively to the field of the production of display structures which are used for the display of articles in general to the public and which are intended, for example, to be installed in shops, on fair stands, and the like.

In this field, the need is known to provide a capability for the various elements of the display structure to be connected to one another by means of quick connection systems which facilitate the assembly and dismantling operations that are quite frequent in the field and which, at the same time, ensure a firm coupling between the elements when they are connected to one another.

A known type of connection system which is already used in this technical field is that defined by bayonet-type connection systems; this term is intended to indicate, in this context, the type of system in which two elements are, engaged and connected by means of a first, translational movement of one element relative to the other along a coupling axis, followed by a second, rotary movement of one element relative to the other about the coupling axis, so as to lock the two elements relative to one another.

These systems typically comprise fastening means which are provided on one of the two elements to be connected, and which include one or more appendages that extend radially from the element and can be housed in respective holes or notches formed on the other of the two elements.

However, this compromises the aesthetic appearance of the structure in the connection region, particularly when the two elements concerned are tubular elements connected as longitudinal extensions of one another.

Moreover, these systems, which provide fastening means and counter- means that are shaped differently from one another, have limited flexibility and are quite complex structurally.

Disclosure of the invention The problem underlying the present invention is that of providing a quick connection system, particularly for the connection of elements of display structures, which is designed structurally and functionally to overcome the limitations set out above with reference to the prior art mentioned.

Within the scope of this problem, a further object of the invention is to provide a connection system which can be used readily and intuitively.

A further object of the invention is to provide a connection system such that the display structure is strengthened in the region of its connections.

This problem is solved and these objects are achieved by the present invention by means of a quick connection system formed in accordance with the appended claims.

Brief description of the drawings The characteristics and the advantages of the invention will become clearer from the detailed description of a preferred embodiment thereof which is described by way of non-limiting example with reference to the appended drawings, in which: - Figure 1 is an exploded, schematic view of a quick connection system formed in accordance with the present invention, - Figure 2 is a perspective view of a detail of the system of Figure 1, - Figure 3 is a schematic view of some details of the system of Figure 1 in assembled condition, - Figure 4 is a schematic, perspective view of the system of Figure 1 in a first coupling step, - Figure 5 is a schematic view of the system of Figure 1 in coupled condition, - Figure 6 is a schematic, perspective view of a variant of the connection system according to the invention.

Best mode for carrying out the invention With initial reference to Figures 1 to 5, a quick connection system, generally indicated 1 and formed in accordance with the present invention, is intended for the connection of a first element and a second element, indicated 2 and 3, respectively, of a display structure, not shown.

The elements 2 and 3 are tube portions of circular cross-section, which extend along a longitudinal axis X and in which respective internal cavities 2a, 3a and free ends 4 and 5 are identified.

The system 1 further comprises two connecting bodies 6a and 6b which are shaped identically to one another and which are fixed in the internal cavity 2a of the element 2 and in the internal cavity 3a of the element 3, respectively.

Each connecting body 6a, 6b comprises a cylindrical base 7 of axis X and a hook-shaped projection 10 extending axially from the base 7.

The base 7 has a circular cross-section which, advantageously, is substantially equivalent to the internal cross-section of the elements 2 and 3 so that it is housed in the cavities 2a, 3a with minimal clearance.

The hook-shaped projection 10 comprises a foot 11 extending axially from the base 7 and a head 12 extending substantially at right angles from the end of the foot 11 remote from the base 7.

The hook-shaped projection 10 as a whole is therefore"L"-shaped and is defined laterally by a flattened surface 13 and by a partially cylindrical surface 14 which constitutes an extension of the lateral surface of the base 7.

Preferably, the cross-section of the head 12 is semicircular, is delimited by the surfaces 13 and 14, and can be superimposed substantially on one half of the circular cross-section of the base 7. The foot 11 in turn has a quadrant- shaped cross-section which is delimited, in addition to the surfaces 13 and 14, also by an abutment surface 15 substantially perpendicular to the surface 13, and which can be superimposed substantially on one half of the cross-section of the head 12 and on one quarter of the cross-section of the base 7.

Moreover, the axial dimension A of the foot 11 is equal to or greater than the thickness B of the head 12.

The connecting bodies 6a, 6b and the elements 2,3 are locked relative to one another by respective pin couplings 16 (housed in respective holes 16a formed in the bases 7) in a manner such that the head 12 projects completely from the respective end 4,5, whereas the feet 11 and the bases 7 of the connecting bodies 6a, 6b remain housed inside the cavities 2a, 3a. A symmetrical configuration of the two elements 2,3 is thus achieved. The

connecting bodies 6a, 6b may, however, be fixed in the respective elements 2, 3 asymmetrically, with one connecting body projecting farther from the end 4, 5 than the other.

The elements 2 and 3 are connected by means of a first step in which the two elements are moved towards one another along the axis X, which is therefore also described as the coupling axis of the system, so that the head 12 of each of the two elements is inserted in the internal cavity of the other of the two elements through the respective end 4,5 (see Figure 4, in which the element 2 is shown in broken outline for greater clarity of the relative coupling positions).

It will be noted that the head 12 of one element is housed in the recess defined by the hook-shaped projection 10, by the base 7, and by the tubular element portion adjacent the ends 4 and 5 of the other element.

Moreover, the step of the insertion of the head 12 fixed to one element is advantageously guided by the flattened surface 13 of the hook-shaped projection fixed to the other element.

Once the insertion step is completed by the abutment of the end 4 of the element 2 against the end 5 of the element 3, one of the two elements is rotated through approximately 90° about the axis X until each head 12 is stopped by the abutment surface 15 of the foot 11 of the other element.

The two elements 2,3 are thus locked in position by virtue of the interference of the heads 12; in particular, relative slipping-out along the coupling axis X is prevented.

It will be noted that, by virtue of the connection system of the present invention, the profile of the structure in the coupled condition remains substantially continuous in the region of the connection of the two elements (see Figure 5), without any projecting portions. The overall aesthetic effect of the structure is thus not penalized.

In order to disconnect the two elements 2,3, it suffices to rotate one element through 90° relative to the other in the opposite direction and to slip the hook-shaped projections 10 out along the coupling axis X.

Figure 6 shows a connection system 50 constituting a variant of the embodiment described above, in which similar details are identified by the

same reference numerals. The connection system 50 is particularly suitable for the connection of a tubular element 51 substantially similar to the elements 2,3 of the previous embodiment to a fastening element 52 mounted on a wall 53. The fastening element 52 comprises a bush 54 and a connecting body 6a housed inside the bush. Preferably, in this variant, the end of the head 12 does not project from the open end of the bush, but is at most flush therewith.

The connecting body 6a is also fixed coaxially in the bush 54 and the respective cross-sections are such that an annular seat 55, which can house a free end 4 of the tubular element 51, is defined between the connecting body and the internal wall of the bush.

A connecting body 6b is fixed inside the tubular element 51 and, in this case also, the head 12 preferably remains inside the cavity of the tubular element 51. The insertion of the element 51 in the seat 55 can thus continue until the end 4 abuts the base of the seat 55 or until the connecting bodies 6a, 6b are in abutment by means of their respective heads 12. The connection is locked by a rotation about the coupling axis, as in the previous embodiment.

The present invention thus solves the problem discussed above, achieving the objects proposed and, at the same time, offers many further advantages, amongst which is greater firmness of the structure as a whole in the region of the coupling between the two elements owing to the presence of the connecting bodies which act as cores of the tubular elements.

A second advantage is that the particular shape of the heads enables the two elements to be engaged solely when they are aligned in a specific angular position so that the procedure for the connection of two elements is predefined and repeatable.

A third advantage is that the connecting bodies provided in the two elements are shaped identically to one another, thus permitting a saving in terms of the types of parts to be produced.