Object of the present invention is a new lifting system for a disappearing protection grille with folding packing, which allows to reduce the space taken in the box by the grille, after its lifting. This occurs thanks to the use of two concentric guides inside which there are arranged the bars which constitute the protection grill and of an axis of rotation comprising one or more cams shaped as equilateral polygons having even number of sides, better described in the following, which at the vertexes have grooves which can accommodate the bars of the grille arranged alternately at different distance from the centre of rotation and which allow the bars of the grille to engage alternately the inner guide or the outer guide.

In comparison to the state of the art, the system object of the present invention can work without using chains, pinions, racks and bushings with different lengths or diameters, as it occurs in the current state of the art, and therefore it is advantageous in terms of costs, dimensions, weight and easiness of usage. At the state of the art there are known various lifting systems for disappearing protection window frames.

In particular, the present invention relates to protection grilles comprising a series of parallel horizontal "bars", arranged at the same distance with respect to each other, each adjacent couple of bars being connected by one or more connecting rods hinged on the same bars, so that it is allowed the rotation of the connecting rods with respect to the bars, but not the axial displacement of the same. According to a traditional system known at the state of the art, a protection grille as the one described is lifted back by winding it on a cylinder which, obviously, has an increasing diameter as the number of the meshes rolling thereon increases. Therefore, there are needed great boxes which force to reduce the height of the door or window protected by the grille, in addition to invade the inner space of the room.

As an alternative to this system, on the market there are available solutions which provide the folding packing of the grille with the horizontal bars being guided to be automatically arranged upwards and downwards, thus creating a horizontal developing packing. In this connection it is significant the patent DE69636003T2 which describes a grille comprising a series of parallel bars which at their ends, on both sides, have extensions of two different lengths, alternately between one bar and the next one, so that there are not two adjacent bars with extensions of equal length. This allows the bars with longer extension to be guided so that they are positioned, thanks to suitable guides, in the lower part of the packing, while the shorter bars, since they do not abut said guides, continue upwards and go to be packed on the upper alignment. Concerning the lifting, this solution provides the use of two closed chains, one for each side, arranged in a suitable recess, which extend on the whole length of the grille, and which allow its lifting thanks to a low coupling.

The above described system is disadvantageous for the excessive space and the complication leading to the needed realization of the longer extensions of the bars guide, in addition to the space to be destined to the lifting chain accommodation, which on both sides extends on the whole height of the window frame.

A second device known at the state of the art, for example presented on the market by Sairam company, was proposed as an improvement in terms of reduction of the excessive dimensions caused by the lifting chain housing of the above cited patent. In this device, the end connecting rods have been modified by adding backwards projecting toothing which, by engaging one motorized pinion arranged in the upper portion, allow the grille to be lifted eliminating the use of the chain, which is substituted by the same toothed connecting rods. In this way, the connecting rods have the double function of guaranteeing the continuity of the grille and of allowing the same to be lifted. However, also this embodiment leads to the need for extensions of different length at the ends of the grille bars, and so to arrange the guides which allow the packing on two different planes. Moreover, the provision of the toothing makes the realization of the connecting rods difficult, with consequent increasing of costs and leads to an increase in the depth of the packing. Another drawback is the remarkable specific load of the toothing of the connecting rods which leads to wear, deformation and increasing friction over the time .

Finally, each embodiment known at the state of the art is limited since requires great volumes to accommodate the protection grille; this aspect is very problematic both in case of walls with limited thickness and in case of very high window frames, considered the great number of elements.

Aim of the present invention is to provide a lifting device for disappearing protection grilles which solves the drawbacks linked to the embodiments known at the state of the art.

According to another aim, the present invention provides a disappearing protection grille which, in comparison to the state of the art, allows to reduce costs, assembling times and dimensions, thus eliminating the use of complex mechanisms such for example chain dragging, the provision of guides arranged on different planes or the use of toothed connecting rods.

According to another aim, the present invention provides a disappearing protection grille, whose ease of actuation allows the use of a manual control, which is useful in case of failure of the electric motorization, but also as a substitute of the latter at least for the -smallest grilles.

Moreover, the present invention provides a disappearing protection grille whose mechanism allows to solve the generally known drawbacks linked to the width of the disappearing grilles. The present invention achieves the prefixed aims since it is a lifting device for disappearing protection grilles comprising a grille made up of a series of parallel bars having bushings of equal length at the ends and constrained by connecting rods; guides at least partially shaped as concentric arcs to an axis, the final sections of said guides being arranged so that the packing of the protection grille is allowed; wheels shaped as equilateral polygon with even number of sides having recesses in each vertex at alternate distance from the centre which allow to engage the bushing relative to adjacent bars, characterized in that in the lifting step of the grille the shaped wheels constrain the bushing engaged in the recess arranged at major distance from the centre to engage the outer guide, while the next bushing, engaged in the recess arranged at minor distance from the centre is pushed by the dragging force exerted by the previous bushing and by the weight of the grille to engage the inner guide.

These and other advantages will be clear from the detailed description of some preferred embodiments of the present invention, which refers to the appended drawings : In fig. 1 it is shown a basic scheme for the dragging and packing of the grille according to the present invention;

In fig. 2 there are schematized the geometric features of a preferred embodiment of the dragging cam;

In fig. 3 it is shown the mechanism by means of which the bushing at the end of one of the bars forming the grille engages the inner guide;

In fig. 4 it is shown another embodiment of the device according to the present invention, in which the packing guides are arranged in horizontal direction;

In fig. 5 it is shown an embodiment of the present invention in which the sliding guides for packing closing the grille are suitably arranged at distance from the sliding plane of the grille so that the space for housing a roller shutter is obtained;

In fig. 6 it is shown a tridimensional assembly view of the invention;

In fig. 7 it is shown an embodiment of the invention comprising an hexagonal shaped wheel;

In fig. 8 it is shown a tridimensional assembly view of the embodiment of figure 7. Referring to fig. 1 in which it is described the geometry of a preferred embodiment of the device, it is possible to highlight that this one comprises a guide (1) in which the grille (2) slides.

Said grille (2) is provided with a series of parallel bars (4) connected by connecting rods (3) . As stated, the connecting rods (3) can rotate with respect to the bars (4) . The bars (4) are constrained so that they have to slide inside the guide (1), in which there are engaged the bushings (5) provided at both ends of each of said bars (4) . Said bushings (5) can be conveniently all of the same length.

The lifting device comprises also a shaped wheel (10), whose geometric features according to a preferred embodiment are shown in figure 2, which shaped wheel is assembled so that it can rotate around an axis of rotation (24) parallel to the direction in which the bars (4) of the grille are arranged.

As it is shown in figure 2, the shaped wheel (10) is shaped as an equilateral polygon with even number of sides (4 sides in figure 2), and at each vertex has a recess (12, 13) apt to be engaged by the bushing (5) arranged at the end of each bar (4) . The geometry of the shaped wheel (10) is such that two adjacent recesses (12, 13) are always at such a distance that the bushings (5) of adjacent bars engage in sequence said recesses. Alternately, in case the shaped wheel (10) is arranged in the middle and not at the end of the axis of rotation (24), the bars (4) can engage said recesses (24). Said recesses (12, 13) have also the feature, visible in fig. 2, according to which, the bushing (5) enters and goes out from the recess in which it is housed, when the adjacent bushing is yet engaged, thanks to the shape of said grooves having jointing spokes (16) and (17) which determine the rotation of the entering bushing (51) around the axis of the engaged bushing (5) .

Moreover each couple of recesses (12, 13) belonging to the adjacent vertexes of the polygon is arranged so that it is at different distance from the axis of rotation (24 ) .

During the lifting step of the grille, the bushings (5, 18) slide upwards on the guide (1) until they arrive to the upper portion of said guide, from which other two guides (6, 7) extend, which have at least a first section of circular shape. Said guides (6, 7) are arranged concentrically with respect to the centre of this first section of circular shaped guide. According to a preferred embodiment, the centre of these circular guides corresponds to the axis of rotation (24). Referring to figure 1, (7) indicates the inner guide and (6) the outer guide.

In particular, the arrangement of the axis of rotation (24), of the shaped wheel (10) and of the guides (1, 6, 7) is such that the bushings (5, 18) are introduced alternately in one of the two concentric guides (6, 7), thus allowing the disappearing closing shown in figs. 1, 4, 5 and 6 to be realized. The device functioning is better described in the following.

As it is shown in fig. 1 in the upper portion of the guide (1) it is provided a widening (9), on which there are opposed the two concentric guide (6, 7) . In fig. 1, it is shown the moment in which a bushing (18) engaged in the groove (12) arranged at major distance from the axis of rotation (24) is forced to enter the outer guide (6). The distance (15) of the groove (12) with respect to the axis of rotation (24) prevents the bushing (18) to enter the inner guide (7).

The adjacent bushing, engaged in the groove (13) arranged at minor distance from the axis of rotation (24) in not mechanically forced not to enter the outer guide (6), but the geometry of the system is such that, as it is shown in figure 3, when the bushing (5) arrives at the widening (9) on which there are opposed the concentric guides (6, 7), the previous bushing (18), which has yet entered the outer concentric guide (6), exerts on the adjacent bushing (5) a direct force along the axis of the connecting rod (3) . This is due to the fact that the connecting rod (3) is constrained by means of two hinges to the couple of adjacent bars, and so it can transmit force only in the direction of the same connecting rod. The same occurs to the connecting rod constraining the lower bar of the grille, which transmits the weight of the grille only along the direction of connection between the two bars.

The scheme of the forces acting on the bushing (5) in figure 3 is such that on the same it is provided a component directed inwards, which pushes the bushing (5) to engage the recess (13) correctly and so to enter the inner concentric guide (7) .

In both cases, once the bushing introduction in the concentric guides has occurred, a baffle (8) limits the bushing movement along the engaged path.

In order to guarantee the correct functioning of the system it is needed to guarantee that there are always two bushings (5, 18) engaged in the respective recesses (13, 12) of the shaped wheels (10), with the consequent movement evenness. The number of the bushings engaged is determined by the amplitude of the arc made up of the first circular portion of the concentric guides.

According to a preferred, yet not limiting embodiment, said guides (6) and (7) extend at least for a circle arc (22) greater than 180°.

At the end of said arc (22), the two guides (6) and (7) continue separated accompanying the bushings until the packing (11) which, as a whole, allows a very reduced and well lower depth than the one according to the state of the art. The final portion of the guides where the packing of the grille (11) occurs can be conveniently arranged vertically as it is shown in figure 1, horizontally as it is shown in figure 4 or according to what is best suited to the particular situation without departing from the scope of the present invention. With respect to the state of the art, it is to be underlined that in the lifting device according to the present invention, all the bushings (5) are of equal length and after reaching the widening (9) of the vertical guide (1) where there are opposed the two concentric guides (6) and (7), enter alternately the one or the other of said concentric guides, thus solving the need, typical of the state of the art, to use bushings of different length, and, so, guides positioned on different planes.

This aspect represents a simplification and a space gain, while the task to shunt alternately the bushings on one or the other guide is carried out by the shaped wheels (10), which have also the task of the grille lifting.

Conveniently a motorized actuation can be arranged on the axis (24) connecting said shaped wheels (10) . In particular a gear-motor can be introduced inside the tube connecting the shaped wheels (10), with further saving in terms of space and structural simplification with respect to the state of the art.

Another advantage of the device according to the present invention is the possibility to use guides (1) which are not necessarily vertical. The device is in fact able to work perfectly also with inclined linear or curved profiled guides (for example having parable arc shape) .

When the grille provides also the presence of an obscuring device, the invention can be organized as in fig. 5 or as in fig. 7. In fig. 5 it is shown an embodiment of the device in which the winder (23) for the obscuring device is arranged behind the grille (2), under the shaped wheels (10) and before the vertical packing (11), which is conveniently backed to accommodate the roller shutter. The only variation with respect to the embodiment yet described is in the geometry of the final portion of the guides. In this case the engagement arc of the bushings for the lifting is greater than 180° but at least two bushings are always engaged.

According to another embodiment intended to make uniform the functioning of the device, in the packing section (11) one of the guides for the bushings has a width greater than the one strictly needed to make the bushings slide, so that it is prevented that in the horizontal lifting or displacement, the small inclination of the connecting rods can cause an increase in friction up to their blocking. This is clear for the guide (7) shown in fig. 1 and 4. In particular it is the inner side of the guide (7), which is distanced from the outer side, thus increasing the useful width for the connecting rods.

As stated, in the case of height limits, the invention can be organized also with horizontal packing as it is shown in fig. 4, where the guides (6) and (7) extend in horizontal while the entering, selection and dragging system remains the same of the basic scheme of figs. 1, 2 and 3.

Besides the yet described option of an electric motorization installed inside the axis (24) on which the shaped wheels (10) rotate, the device according to the present invention admits also the possibility of a manual control, shown in fig. 4, which is also suitable for the other configurations of fig. 1 and fig. 5, and which is made up of a pulley (26) integral with the axis of rotation (24) on which a roller shutter belt or steel cable (27), which is provided with a crank organ (28), winds u .

In order to simplify the movement of the grille which can be problematic, particularly when there is no electric actuation, it is possible to accommodate a torsion spring (29) inside the central tube, in place of the motorization, conveniently configured so that it pushes the grille downwards when the same is completely wound, and upwards when the same is completely lowered. The thrust has to be such that the movement of the grille is simplified, but at the same time has to be sensibly lower than the push needed for moving the grille without an outer force. In fig. 6 there are shown clearer the components of the invention intended for the lifting and packing of a disappearing grille, highlighting in particular the relative planes of action, with in the middle, the grille made up of bars (4) and connecting rods (3), while at the end after the outer connecting rods (3), the bushings (5) which, besides engaging the grooves (12) and (13) of the shaped wheels continue to be channeled by the guides (6) and (7), positioned on two outermost vertical planes (27) of the system, where there are anchored also the supports of the motorized central axis .

According to another embodiment, the device object of the present invention can comprise obscuring winding means, such for example a rolling gate or a roller shutter, configured to be conveniently wound without increasing the device dimensions.

As it is shown in fig. 5, in fact, the device comprises obscuring winding means which wind up around a rotating winder (23) arranged inside the region defined by the guides (1) in the front portion and by the end portion (11) in the rear portion of the guides of the grille.

According to a preferred variant, the winder for the obscuring winding means can rotate around the same axis (24), which is suitably provided with a shaft concentric to the one where there are keyed the shaped wheels (10) and is able to rotate independently of the same.

To the obscuring means can be also associated electric movement means, which are positioned concentrically to the axis (24) or near the same. Using the mechanisms known at the state of the art, it is also possible that only one electric actuation means actuates, selectively, the grille or the obscuring means.