FIELD OF THE INVENTION

The present invention relates to a guiding device for coplanar doors of furniture and to a piece of furniture with coplanar doors comprising such guiding device. PRIOR ART

In the furniture sector, coplanar door systems nowadays represent an increasingly popular solution, which is highly appreciated for its particular functional and appearance features, as an alternative to traditional sliding door systems. Indeed, such systems combine the advantages of traditional sliding doors, in particular that of small dimensions in opening position, with the typical features of swing doors, in particular the possibility to arrange them on a single common plane in closing position, and thus to form a continuous planar surface, free from steps, in the closed condition.

The opening and closing of a coplanar door requires the combination of two movements: a movement perpendicular to the plane of the door, to make the door exit from (opening) or return it to (closing) a closing plane and a movement parallel to the plane of the door, to make it slide on a sliding plane, spaced from and parallel to the closing plane, e.g. superimposed on an adjacent coplanar door, so as to discover/cover a respective compartment. In practice, these movements are usually combined with a continuous movement, in which the door also performs a partial rotation about an axis defined by the respective moving system, typically a vertical axis.

Typically, in case of furniture, a coplanar door is actuated manually. The correct movement of the doors is ensured by appropriate moving devices, by means of which the doors are associated with the respective piece of furniture. The moving devices for coplanar doors normally comprise carriages which can translate along rails arranged parallel to the closing plane of the doors, at the top and/or the bottom of the piece of furniture on which mechanisms are mounted. The mechanisms are appropriately configured to allow the coplanar door to perform said movements, in particular, the translational movements and partial rotation to exit from and return to the closing plan. Typically, guiding devices are also provided, having the two-fold function of guiding the coplanar door while opening and closing so that it remains vertically parallel to the closing plane, thus avoiding harmful vertical oscillations, and of transmitting, or contributing to transmitting, the movements determined by moving devices along the height of the door. This second function is particularly important if the moving devices are present only either at the top or at the bottom of the piece of furniture, and therefore their movements are transmitted to the door only at either its top or bottom side.

WO 2016/059488 A1 discloses a piece of furniture with a sliding door mechanism. Each door is supported with respect to the piece of furniture by means of a pair of brackets connected to carriages sliding in a rail arranged at the top of the piece of furniture. An articulated mechanism mounted onto a wall of the cabinet, internally thereto, and associated in sliding manner with the respective door on the inner side thereof is also provided to support and guide each door. The articulated mechanism comprises a pair of first arms hinged to the piece of furniture about a first vertical axis by means of two respective brackets, at positions spaced along the height of the piece of furniture. A pair of second arms is hinged respectively to the first arms about a second vertical axis, parallel to the first vertical axis. A wheel with a rotation axis parallel to the first and second vertical axis is mounted at the free ends of each of the second arms. Each of the wheels can slide in a corresponding guide mounted on the inner side of the door. A pair of bars which vertically connect the first arms and the second arms to each other is provided in order to increase the rigidity of the mechanism.

The performance of the known guiding devices for coplanar doors of furniture based on an articulated mechanism such as the one described above is not entirely satisfactory.

Indeed, it has been found that such guiding devices do not always ensure a smooth movement of the door, above all in the steps of exiting from and returning to the closing plane. In addition to being generally unwelcome to users, this drawback may on the long run also damage the guiding devices and/or moving devices of the door, because such devices may be subjected to forces higher than those planned and/or not congruent with their operation when particular resistance must be overcome during the movement of the door.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide a guiding device for coplanar doors of furniture which overcomes the drawbacks of the known similar guiding devices described above. More in particular, it is an object of the present invention to make available a guiding device for coplanar doors of furniture which can ensure a smooth, continuous motion of the respective coplanar door in all steps of opening and closing moving of the door itself.

It is a further object to increase the stiffness of the guiding device and to reduce the clearance, in particular at the turning hinge constraints present between the elements of the guiding device.

Such object is achieved by a guiding device for coplanar doors of furniture having the features set forth in the attached claim 1 . Preferred embodiments of such guiding device are defined in the dependent claims.

In particular, the invention relates to a guiding device for coplanar doors of furniture, comprising a first articulated quadrilateral kinematic mechanism and a second articulated quadrilateral kinematic mechanism, arranged respectively at opposite longitudinal ends of the guiding device. According to the invention, each articulated quadrilateral kinematic mechanism comprises:

- a fixed element, rigidly constrainable to the body of said piece of furniture to associate the guiding device with the body of said piece of furniture,

- a first crank, constrained to said fixed element by means of a first hinge constraint so as to be rotational with respect to said fixed element,

- a second crank, constrained to said fixed element by means of a second hinge constraint so as to be rotational with respect to said fixed element,

- a connecting rod, constrained to said first crank by means of a third hinge constraint and to said second crank by means of a fourth hinge constraint, said connecting rod being constrainable to a respective coplanar door of said piece of furniture to associate the guiding device with said coplanar door, said first crank of said first articulated quadrilateral kinematic mechanism and said first crank of said second articulated quadrilateral kinematic mechanism being connected to each other by means of a first stiffening bar.

In the present description and in the appended claims, the expression "coplanar door", in particular of a piece of furniture, means a sliding door associated with a respective piece of furniture so that, when in the closing position, it can lie on the same plane as the other wall portions of the piece of furniture adjacent to the door itself, in particular on a same closing plane as other doors of the piece of furniture. This feature affects the type of movement required to open/close the coplanar door, in which movements both parallel and perpendicular to the closing plane are combined.

In the guiding device of the invention, the presence of two quadrilateral kinematic mechanisms makes it possible to guide the furniture doors efficiently, whereby guaranteeing a smooth, continuous motion of the respective coplanar door in all steps of moving of the door, when opening and when closing.

The two hinge elements of the hinge mechanism are mutually coupled along their entire active length by the stiffening bar provided between two corresponding cranks of each quadrilateral mechanism. This feature, in addition to contributing to the stability of the guide, advantageously makes it possible to transmit the movements determined by the respective moving unit, in particular the rotation movements and the respective twisting moments, continuously and therefore synchronously along an entire side, e.g. a vertical side, of a coplanar door. The movement of the coplanar door can thus be smoother and more regular, avoiding, or in any case minimizing, any additional forces required by the user due to the presence of the guiding device, on the one hand, and any improper stresses on the moving and/or guiding devices which can occur if the door is forced, on the other.

In a preferred embodiment of the device, the connecting rods of the two quadrilateral kinematic mechanisms are also mutually connected by means of a second stiffening bar. This further increases the stiffness and decreases their clearances, in particular at the hinge constraints between the connecting rods and the corresponding cranks for each of the two quadrilateral kinematic mechanisms.

Preferably, the first hinge constraint and said second hinge constraint are reciprocally arranged so that when said fixed element is rigidly constrained to the body of said piece of furniture, the first hinge constraint is closer to the respective coplanar door of said second hinge constraint. This determines that, with respect to the coplanar door to be moved, the first crank of the articulated quadrilateral kinematic mechanism, i.e. the crank to which the first stiffening bar is rigidly coupled, is in the advanced position, i.e. closer to the door with respect to the other crank of the corresponding articulated quadrilateral kinematic mechanism. Such constructional expedient also contributes to making the movement of the respective coplanar door smoother and more continuous than the solutions of the prior art.

The present invention also relates to a piece of furniture with coplanar doors comprising a guiding device for coplanar doors as described above.

Such piece of furniture with coplanar doors have all the advantages, in terms of the possibility of smoothly moving and of adjusting the respective doors, previously described with reference to the guiding device.

BRIEF DESCRIPTION OF THE FIGURES

Further features and advantages of the guiding device of the invention will be more apparent in the description of the following preferred embodiments, by way of indicative, non-limiting example, with reference to the accompanying drawings, in which:

- Fig. 1 is a side view of a piece of furniture comprising a guiding device for coplanar doors of furniture according to the present invention;

- Fig. 2 is a prospective view of components of the guiding device in figure 1 ;

- Fig. 3 is an enlarged view of a detail, indicated by III in Fig. 2, of the view in Fig.

2;

- Fig. 4 is a plan view of two guiding devices corresponding to that shown in Fig. 1 , mounted on a piece of furniture with coplanar doors, in the configuration assumed when a corresponding coplanar door is either closed or completely open, respectively;

- Fig. 5 is a perspective view of a guiding device for coplanar doors of furniture according to the present invention in a first operating configuration;

- Fig. 6 is an enlarged view of a detail, indicated by VI in Fig. 5, of the view in Fig.

5;

- Fig. 7 is a perspective view of a guiding device for coplanar doors of furniture according to the present invention in a second operating configuration;

- Fig. 8 is an enlarged view of a detail, indicated by VII in Fig. 7, of the view in Fig.

7;

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Figs. 1 -8 show a preferred embodiment of a guiding device for coplanar doors of furniture, indicated as a whole by reference numeral 100, in accordance with the present invention.

The guiding device 100 is intended to be mounted in a piece of furniture with the coplanar doors, as diagrammatically shown by way of example in Figs. 1 and 2 and indicated as a whole by reference numeral 300.

The piece of furniture 300 comprises a body formed by a top wall 301 , a bottom wall 302, a pair of side walls 303 (of which only one is shown in the figures) and a rear wall 304. The body of the piece of furniture 300 is divided internally, by way of example, into two compartments by means of a vertical dividing wall 305 (see Figure 4) and is correspondingly closed on its front side by two coplanar doors 306, 307.

In a closed condition, the doors 306, 307 lie in a single common closing plane. When instead one of two doors 306, 307 is in an either partially or fully open condition, it is partially or completely superimposed on the other of the two doors 306, 307, as shown in Figs. 1 -4.

The doors 306, 307 are associated with the body of the piece of furniture 300 by means of moving devices 200, only partially shown in Figure 1 , which also perform a supporting function of the doors.

The moving devices 200 comprise carriages which can translate along rails which extend parallel to the closing plane of the doors 306, 307 and can be arranged at the top wall 301 , as in the case of piece of furniture considered here, and/or in the bottom wall 302 of the body of the piece of furniture 300. The carriages support articulated mechanisms connected to the doors 306, 307 and appropriately configured to allow them to perform in a controlled manner the movements for exiting from and returning from the closing plane, typically translation movements in a direction perpendicular to the closing plane and partial rotation around a vertical axis, possibly movable parallel to the closing plane. Since the specific shape of the moving devices 200 is not relevant for the purposes of the present invention, they are not described herein in greater detail.

The doors 306, 307 are associated with the body of the piece of furniture 300 also by means of respective guiding devices 100, having the two-fold function of guiding the coplanar door during opening and closing so that it remains vertically parallel to the closing plane and of transmitting the movements determined by the moving devices 200 along the height of the door. More in particular, for each door 306, 307 a guiding device 100 is provided, associated with a fixed manner to the body of the piece of furniture 300 at the partition wall 305 and in sliding manner with the respective door 306, 307.

A preferred embodiment in accordance with the present invention of a driving device 100 used in piece of furniture 300 for guiding the movements of one of its doors 306 or 307 is described in detail with reference in particular to Figs. 3-8. The guiding device 100 used for moving the door 306 is the same and specular to the guiding device 100 used for moving the door 307 with respect to the partition wall 305. For this reason, the two guiding devices 100 shown in the accompanying figures are described with reference to the same numerical references.

The guiding device 100 comprising a first articulated quadrilateral kinematic mechanism 10 and a second articulated quadrilateral kinematic mechanism 20, arranged respectively at opposite longitudinal ends of the guiding device 100. Each articulated quadrilateral kinematic mechanism 10, 20 respectively comprises a fixed element 15, 25 rigidly secured to the body of the piece of furniture 300, in particular to the dividing wall 305, to associate the guiding device 100 respectively with the body of the piece of furniture 300 and to one of the doors 306 or 307. The fixed element 15, 25 is a fastening element adapted to allow the stable fixing of the guiding device 100 to the body of the piece of furniture 300 in known manner. In the preferred embodiment shown in the accompanying figures, the fixed element 15,25 has a box-like configuration and can therefore optionally accommodate auxiliary devices, such as for example a damping element 310 to damp the impacts of the door 306 or 307 against the body of the piece of furniture 300 when it closes. Naturally, as needed, other types of fastening elements, also not box-shaped, can be chosen, such as plates or mounting brackets, types in any case known to a person skilled in the art.

Each articulated quadrilateral kinematic mechanism 10, 20 respectively also comprises a first crank 1 1 , 21 constrained to the fixed element 15, 25 by means of a first hinge constraint 31 , 41 so as to be able to turn with respect to the fixed element 15, 25.

Each articulated quadrilateral kinematic mechanism 10, 20 respectively also comprises a second crank 12, 22 constrained to said fixed element 15, 25 by means of a second hinge constraint 32, 42 so as to be able to turn with respect to the fixed element 15, 25.

The first hinge constraint 31 , 41 and said second hinge constraint 32, 42 are reciprocally arranged so that when said fixed element 15, 25 is rigidly constrained to the body of the piece of furniture 300 the first hinge constraint 31 , 41 is closer to the coplanar door 306, 307 of the second hinge constraint 32, 42. In practice, with respect to the coplanar door 306, 307 to be moved, the first crank 1 1 , 21 of the articulated quadrilateral kinematic mechanism 10, 20 is located in advanced position, i.e. closer to the coplanar door 306, 307, with respect to the second crank 12, 22.

Each articulated quadrilateral kinematic mechanism 10, 20 respectively also comprises a connecting rod 13, 23 constrained to the first crank 1 1 , 21 by means of a third hinge constraint 33, 43 and to the second crank 12, 22 by means of a fourth hinge constraint 34, 44.

In the variant embodiment in the accompanying figures, the articulated quadrilateral kinematic mechanism 10, 20 is of the parallelogram type, the distance between the first hinge constraint 31 , 41 and the third hinge constraint 33, 43 being nearly equal to the distance between the second hinge constraint 32, 42 and the fourth hinge constraint 34, 44.

All hinge constraints 31 , 41 , 32, 42, 33, 43, 34, 44 are arranged to allow respective rotations about respective axes substantially parallel to the coplanar doors 306, 307 and substantially orthogonal with the top wall 301 and to the bottom wall 302 of the body of the piece of furniture 300.

The connecting rod 13, 23 can be connected to the respective coplanar door 306, 307 of the piece of furniture 300 to associate the guiding device 100 with the coplanar door 306, 307.

In order to allow such constraint between connecting rod 13, 23 and coplanar door 306, 307, the connecting rod 13, 23 comprises a rotational wheel 19, 29 which can be engaged in a sliding manner a corresponding guide 51 , 52 provided on the coplanar door 306, 307.

In particular, according to the embodiment in the accompanying figures, the wheel 19, 29 is provided at an end of the connecting rod 13, 23. Alternatively, other types of sliding elements may be used, known to a person skilled in the art, in particular also sliding elements which cannot rotate, e.g. shoes associated in fixed manner with the respective rod 13, 23.

The connecting rod 13, 23 comprises a first portion 16, 26, comprised between the third hinge constraint 33, 43 and the fourth hinge constraint 34, 44, and a second portion 17, 27, adjacent to the first portion 16, 26.

The first portion 16, 26 and the second portion 17, 27 of the connecting rod 13, 23 are mutually arranged so that the third hinge constraint 33, 43 is interposed between the first portion 16, 26 and the second portion 17, 27. In practice, the second portion 17, 27 is an appendix projecting from the respective articulated quadrilateral 10, 20. The second portion 17, 27 of the connecting rod 13, 23 can be rigidly coupled to the coplanar door 306, 307 to associate the guiding device 100 with the coplanar door 306, 307. In particular, this is obtained by constraining the rotational wheel 19, 29 to the free end of the second portion 17, 27 of the connecting rod 13, 23.

According to the present invention, the first crank 1 1 of the first articulated quadrilateral kinematic mechanism 10 and the first crank 21 of the second articulated quadrilateral kinematic mechanism 20 are connected to each other by means of a first stiffening bar 50.

According to the variant embodiment shown in the accompanying figures, the connecting rod 13 of the first articulated quadrilateral kinematic mechanism 10 and the connecting rod 23 of the second articulated quadrilateral kinematic mechanism 20 are also connected to each other by means of second stiffening bar 40. In particular, the second stiffening bar 40 connects the second portion 17 of the connecting rod 13 of the first articulated quadrilateral kinematic mechanism 10 and the second portion 27 of the connecting rod 23 of the second articulated quadrilateral kinematic mechanism 20.

The first stiffening bar 50 and the second stiffening bar 40 extend longitudinally from one to the other of the first and second articulated quadrilateral kinematic mechanisms 10, 20. The longitudinal extension of the guiding device 100 preferably corresponds to the extension in height of the door 306 or 307.

In practice, the assembly formed by the first crank 1 1 of the first articulated quadrilateral kinematic mechanism 10, by the first crank 21 of the second articulated quadrilateral kinematic mechanism 20 and by the first stiffening bar 50 constitutes a single rigid element which extends longitudinally along the guiding device 100 connecting the first and the second articulated quadrilateral kinematic mechanism 10, 20 to each other.

Similarly, the assembly formed by the connecting rod 13 of the first articulated quadrilateral kinematic mechanism 10, by the connecting rod 23 of the second articulated quadrilateral kinematic mechanism 20 and by the second stiffening bar 40 constitutes a single rigid element which extends longitudinally along the guiding device 100 connecting the first and the second articulated quadrilateral kinematic mechanism 10, 20 to each other.

The first stiffening bar 50 and the second stiffening bar 40 are conveniently constituted by respective profiled bars, having cross section capable of providing the required features of rigidity to the system and of smoothness in the opening and closing movements of the coplanar doors 306 or 307 to the guiding device 100. In particular, according to the variant embodiment in the accompanying figures, the first stiffening bar 50 and the second stiffening bar 40 have a flat cross section.

With reference to the accompanying figures 5 and 6, the guiding device 100 is shown in an operative configuration assumed when the corresponding door 306, 307 is in a fully closed condition. In this condition, the guiding device 100 assumes a folded configuration, in which the first and second articulated quadrilateral kinematic mechanism 10, 20 and the stiffening bar 50, 40 are completely accommodated in the compartment of the piece of furniture 300 closed by the door 306, as also shown by the guiding device 100 located to the left of the dividing wall 305 in Figure 4.

With reference to the accompanying figures 7 and 8, the guiding device 100 is shown in an operative configuration assumed when the corresponding door 306, 307 is in a fully open condition.

In this condition, the guiding device 100 assumes a completely unfolded configuration, as shown also by the guiding device 100 placed on the right side of the partition wall 305 as shown in Figure 4. In such configuration, the first crank 1 1 , 21 and the second crank 12, 22 are arranged substantially parallel to the dividing wall 305, while the second portion 17, 27 of the connecting rod 13, 23 which carries the rotational wheel 19, 29 is essentially parallel to the respective door 306, 307.