Technical field

This patent application for an industrial invention relates to a device for correctly laying floor tiles.

Background art

As it is known, floors, or coverings in general, formed of a plurality of ceramic tiles, are still widespread.

When preparing such floored surfaces, one important requirement which arises is that of making the floor perfectly planar while laying it.

Naturally, such a condition can only be guaranteed if the upper surface of each tile adopts a configuration perfectly coplanar with the configuration adopted by the upper surface of all of the other tiles of the same floor .

In order to guarantee the layer greater fitting precision and a faster speed of execution, already some time ago several "alignment" devices were produced, called, in slang, levellers, which are intended precisely to be used for laying various adjacent rows of tiles .

Such prior art levellers comprise a strap and a knob which is suitable for operating in conjunction with the strap. The strap comprises a base plate, intended to be positioned on a sub-floor or on a wall, below two or more adjacent tiles, and a vertical thin plate, jutting centrally from the base plate in such a way as to be positioned in a space obtained between said two or more adjacent tiles. That vertical thin plate ends at the top with a threaded rod and is connected at the bottom to the base plate by means of a lower end with reduced cross-section, suitable for being cut at the moment when the threaded rod, once the tiles are stably fixed, is subjected to pulling/bending stresses.

The knob comprises a flange, which surrounds the base of the knob and which is intended to be abutted on top of the tiles, and a body, jutting above the flange, which consists of a cylindrical cover equipped, starting from its upper closing wall, with a central cylindrical duct, with threaded inner walls, suitable for precisely receiving and with it creating a helical coupling, the threaded rod provided at the top of the strap.

In the case in question, the operator, in order to fit the knob on the strap, must screw the knob onto the threaded rod of the strap, until the flange of the knob is moved into contact with the tiles and applies pressure on the tiles.

In the same way, in order to remove the knob from the strap, the operator must unscrew the knob from the threaded rod of the strap, until they are completely uncoupled .

It is evident that such operations, which must be performed for each leveller, are lengthy, complex and not very practical.

Disclosure of the Invention

The aim of this invention is to overcome the disadvantages of the prior art by providing a knob which can be fitted on a strap in a simple, rapid and practical way, in order to align two or more tiles of a floor.

Another aim of this invention is that of devising a device which allows the correct alignment of two or more tiles in a simple, rapid and practical way.

These aims are achieved in accordance with the invention with the features listed in the appended independent claim 1. Advantageous embodiments appear from the independent claims.

The knob according to the invention is defined by claim 1.

In particular, said knob is characterised in that it comprises a pair of jaws, hinged to each other, which are suitable for defining, in conjunction with each other, a threaded duct suitable for engaging with the threaded rod of the strap.

The advantages of the knob according to the invention appear to be evident, wherein providing two jaws, which are hinged to each other, ensures that the knob can be fastened to and released from the threaded rod of the strap in a simple and rapid way, without having to screw and unscrew the knob, thereby reducing tile laying times.

Brief description of drawings

For a clearer explanation the description of the invention continues with reference to the appended drawing plates, which are provided by way of illustration only and do not limit the scope of the invention, wherein :

- Figure 1 is an axonometric view of a knob according to the invention, in a wide apart configuration;

- Figure 2 is an axonometric view of the knob according to the invention, in a clamped configuration;

- Figure 3 is an axonometric view of a first jaw of the knob according to the invention;

- Figure 4 is similar to Figure 3, but shows the first jaw of the knob from another angle:

- Figure 5 is an axonometric view of a second jaw of the knob according to the invention;

- Figure 6 is similar to Figure 5, but shows the second jaw of the knob from another angle; - Figure 7 is a top view of the knob according to the invention, in a clamped configuration;

- Figure 7A is an enlarged view of the detail contained in the circle A of Figure 7;

- Figure 8 is a cross-section view of the knob of Figure 2, seen along the cross-section plane VIII - VIII of Figure 2;

- Figure 9 is an axonometric view of the device according to the invention, in a disassembled configuration .

Best embodiment of the Invention

With reference to Figures 1 and 2, a knob according to the invention is described, labelled in its entirely with the reference number (1) .

The knob (1) is intended to be used for correctly laying tiles of a floor and is shaped in such a way as to operate in conjunction with a strap (B) .

With reference to Figure 9, the strap (B) is of the prior art type and comprises a base plate (P) , intended to be positioned on a sub-floor or on a wall, below two or more adjacent tiles, and a vertical thin plate (V) , jutting centrally from the base plate (P) in such a way as to be positioned in a space obtained between said two or more adjacent tiles. That vertical thin plate (V) of the strap ends at the top with a threaded rod (S) and is connected at the bottom to the base plate (P) by means of a breakable lower end (VI) with reduced cross-section.

There is nothing to prevent the threaded rod (S) from jutting directly from the base plate (P) of the strap, without said thin plate (V) being interposed between them.

Returning to Figures 1 and 2, the knob (1) comprises a first jaw (10) and a second jaw (20) .

In particular with reference to Figure 1, each jaw (10,20) has a monolithic structure made by moulding plastic materials and comprises an inner face (FI), intended to be directed towards the threaded rod (S) of the strap (B) , and an outer face (F2), opposite to the inner face (FI) and intended to be directed towards the outside .

Each jaw (10,20) comprises a half-seat (30) and a threaded half-duct (40), both made on the inner face (FI) of the jaw (10,20) .

The first and the second jaw (10,20) of the knob are connected to each other in such a way that the knob (1) can adopt a clamped configuration (shown in Figure 2), in which the inner faces (FI) of the first and of the second jaw (10,20) are in contact with each other, and a wide apart configuration (shown in Figure 1), in which the inner faces (FI) of the first and of the second jaw (10,20) are not in contact with each other.

In particular with reference to Figure 8, when the knob (1) is in the clamped configuration, the two half seats (30) and the two half-ducts (40) of the two jaws respectively form a cylindrical seat (31), intended to house the vertical thin plate (V) of the strap, and a threaded duct (41), intended to house the threaded rod (S) of the strap.

Obviously, when the thin plate (V) has a width greater than the diameter of the threaded rod (S), then the width of the cylindrical seat (31) is also greater than the diameter of the threaded duct (41) .

It is also evident that, were a strap (B) without the thin plate to be used, that is to say, with the threaded rod (S) attached directly to the base plate (P) , then the knob (1) would be provided with only the threaded duct (41) .

Advantageously, the threaded duct (41) formed by the two half-ducts (40) has a thread with rounded edges. In that way, when closing the knob (1) on the threaded rod (S) of the strap, if the crest of a thread of the threaded rod (S) were to make contact with the crest of a thread of the threaded duct (41) of the knob, the rounded edges of the thread of the threaded duct (41) of the knob would cause a small sliding of the knob along the threaded rod (S) of the strap, in such a way that the threads of the threaded rod (S) engage precisely with the threads of the threaded duct (41) of the knob.

Returning to Figures 1 and 2, the first and the second jaw (10,20) of the knob (1) are hinged to each other. More precisely, the first jaw (10) comprises a pin (11) and the second jaw (20) comprises two open sleeves (21) which house the pin (11) .

In particular with reference to Figures 5 and 6, each sleeve (21) of the second jaw (20) comprises a radial opening (22) directed towards the outer face (F2) of the second jaw (20), that is to say, directed towards an opposite side of the second jaw (20) relative to the half-duct (40) and the half-seat (30) of the second jaw (20) .

Alternatively, both of the jaws (10, 20) may comprise closed sleeves (21), intended to house an external pivot pin.

Alternatively, the first and the second jaw (10,20) could be connected to each other by means of a flexible thinned portion, made of plastic material, that is to say, the knob (1) could be monolithic and made, in a single piece, by moulding plastic material.

The knob (1) comprises closing means (5) for keeping the knob (1) in the clamped configuration.

In particular with reference to Figures 3, 5, 7 and 7A, those closing means (5) are of the latch type and comprise an elastic pawl (7) connected to the first jaw (1) and shaped in such a way as to be inserted, with an elastic snap-in action, into a slot (8) purpose-made on the second jaw (2) .

The pawl (7) comprises a wedge (70) and a flexible tongue (71) which connects the wedge (70) to the first jaw (10) . In particular, the first jaw (10) comprises a window (A) (shown in Figures 1 and 4) and the flexible tongue (71) of the pawl (7) has a "U"-shape, comprising:

- a straight first portion (Tl) connected to the outer face (F2) of the first jaw (10),

- a curved connecting portion (T2), with concavity directed towards the window (A) of the first jaw (10), and

- a straight second portion (T3), parallel to the straight first portion (Tl), having a first end connected to the straight first portion (Tl), by means of the curved connecting portion (T2), and a second end comprising the above-mentioned wedge (70) .

The straight second portion (T3) of the flexible tongue of the pawl (7) passes through the window (A) of the first jaw (10), in such a way that the wedge (70) projects from the inner face (FI) of the first jaw (10) .

The slot (8) made in the second jaw (20) is delimited by an enlarged edge (80) having an inner surface (81) inclined outwards, in such a way as to act as a guide for insertion of the wedge (70) of the pawl (7) into the slot (8) . The enlarged edge (80) comprises an outer surface (82) having a rib (9) which acts as a locking surface for the pawl (7) inserted into the slot (8) . The wedge (70) of the pawl has an inclined wall suitable for sliding on the inner surface (81) of the enlarged edge delimiting the slot (8) .

As long as the wedge (70) slides on the inner surface flexible tongue (71) of the pawl is subject to gradual elastic bending, thanks to which the flexible tongue

(71) itself is released, to adopt its home configuration again, as soon as there is an end to the interference between the wedge (70) and the inner surface (81) of the enlarged edge delimiting the slot (8) .

The wedge (70) of the pawl (7) also comprises a groove

(72) suitable for housing the rib (9) of the enlarged edge delimiting the slot (8), when the knob (1) is in the clamped configuration.

With reference to Figures 4, 6 and 7, each jaw (10, 20) comprises a semi-annular flange (60) projecting outwards from the outer face (F2) of the jaw (10, 20), that is to say, projecting on an opposite side of the jaw (10, 20) relative to the half-duct (40) and the half seat (30) of the jaw.

Those base semi-annular flanges (60) of the jaws (10, 20) are intended to be positioned on top of the adjacent tiles and form a single annular flange (61), when the knob (1) is in the clamped configuration (as shown in Figure 7 ) .

Each semi-annular flange (60) has a lower surface which is inclined, so that it is sloping outwards, as shown in Figure 8.

With regard to this it should be noticed that, during the step of clamping knob (1) on the threaded rod (S) of the strap, a stress state is generated which tends to force apart the two jaws (10, 20) of the knob.

Therefore, precisely in order to counter that phenomenon, the device of giving each semi-annular flange (60) the above-mentioned inclination was adopted, so that the lower surface of the flange (61) does not lie in a horizontal plane, but instead has the above-

8 mentioned double inclination.

In that way, during screwing of the knob (1) onto the threaded rod (S) of the strap, the peripheral edge of the flange (61) is the first to intercept the upper surface of the tiles.

That means that, during the gradual screwing of the knob (1) against the tiles below, as a reaction, a peripheral thrust is generated which pushes the two semi- annular flanges (60) upwards, generating a bending moment which pushes the two jaws (10, 20) against each other, during screwing of the knob.

The description continues with reference to the method for aligning tiles by means of the device according to the invention.

The base plate (P) of the strap is positioned on a sub-floor or on a wall which is coated with adhesive, and two or more tiles are positioned, adjacent to each other, on said base plate (P) , in such a way that the vertical thin plate (V) of the strap projects from a space obtained between said two or more adjacent tiles.

The knob (1), in the wide apart configuration, is clamped on the threaded rod (S) of the strap, in such a way that the threaded rod (S), along almost its whole length, is accommodated inside the threaded duct (41) of the knob .

In other words, during this step of clamping the two jaws (10, 20), the relative semi-annular flanges (60) brush against the upper surface of the tiles.

Then, the pawl (7) of the first jaw (10) is pushed into the respective slot (8) made in the second jaw (20), so as to cause the two jaws (10,20) to be fastened to each other, which corresponds to a simultaneous insertion of the threaded rod (S) into the threaded duct (41) of the knob. At this point, the operator rotates the knob (1), so as to cause its screwing onto the threaded rod (S) of the strap, which ends at the moment when the flange (61) of the knob abuts, with force, on top of the tiles.

It is during this step that the advantage of the invention is appreciated, since a rotation of the knob (1), even by less than one turn, will be sufficient to reach the screwing end of stroke.

Once the tiles are fixed to the sub-floor or to the wall, the operator can remove the knob (1) from the strap by simply opening the jaws (10,20), by acting on the flexible tongue (71) of the pawl, in order to free the pawl (7) from its gripping slot (8) .

The final operation, which is completely conventional, is that of stressing the threaded rod (S) of the strap in order to cause the vertical thin plate (V) to be torn from the base plate (P) of the strap, whilst said strap remains disposable, trapped under the tiles.

Thanks to the fact that two jaws (10,20) hinged to each other are provided, the knob (1) can be fastened to and released from the thin plate of the strap easily and rapidly, without having to screw the knob onto and unscrew it from the whole length of the threaded rod (S) of the strap, meaning that it speeds up the tile laying times .