DESCRIPTION

The invention relates to a tile levelling device used on a surface to level at least two adjacent tiles. The said device is of the type comprising a support designed to be positioned between at least two adjacent tiles and which, in addition to fulfilling a spacing function, is also equipped with a base envisaged to be placed under the two tiles and an elongated body, which extends vertically from the base in a perpendicular manner thereto. The elongated body is equipped with means to enable gripping thereof from the outside to form a coaxial connection, by means of a thread, with a pressure body. The said body is endowed with a lower edge endowed with a flat support surface intended to operate through contact with parts of the upper surfaces of at least two adjacent tiles. The task of the said flat support surface, which is arranged perpendicular to the central axis of the pressure body, is to perform the levelling, i.e. aligning the upper flat surfaces of the two or more adjacent tiles lying in the same plane when the said support surface is pushed against the upper surfaces of the adjacent tiles, exploiting the counteraction applied by the base to the lower surfaces of the said tiles. This operation is performed using the screw connection, whereby - in accordance with commonly known techniques - the pressure body is screwed onto the thread with which the elongated body is equipped, with the result that the support surface of the pressure body ends up in contact and pushing against the flat upper surfaces of adjacent tiles.

According to the prior art, an example of which is patent EP3455432 (also filed by the said applicant), this operation is performed at each point of the floor at which levelling is carried out and has the drawback of being likely to cause marking or scratching on the upper surface (i.e. the decorative surface) of the portions of the tiles concerned by the levelling. This damage is a result of chafing on the upper surface portions caused during the rotational action, i.e. by the flat support surface of the device scraping the said upper surface during the active step in which the device is screwed tight. Indeed, during the screwing motion on the threaded part of the elongated body, the device is rotated in order to act on the tiles in a perpendicular arrangement, forcing the levelling of the upper surfaces thereof through the counterforce exerted by the base with which the elongated body is endowed and which is located underneath the tiles.

The main object of the present invention is to provide an effective and simple solution to the problem stated.

Advantages provided by the invention include structural and operational simplicity.

This object and further advantages are achieved by the present invention, which relates to a tile levelling device according to the claims, as described and illustrated in the accompanying drawings.

Further characteristics and advantages of the invention will better emerge from the following description of a preferred but not exclusive embodiment thereof illustrated by way of a purely non-limiting example in the accompanying drawings in which:

- Figures 1 and 2 show two axonometric views of the assembly which refer to two steps in the application of the levelling device envisaged in the invention;

- Figure 3 shows a schematic exploded sectional view thereof taken along an axial plane shown by line l-l in Figure 4 below, which shows the step in Figure 1 ;

- Figure 4 shows a top-down view of the part in Figure 3;

- Figure 5 shows the levelling device in the closed position in the same sectional view as in Figure 3;

- Figure 6 shows, on an enlarged scale, a detail which is denoted A in Figure 5; - Figure 7 shows, on an enlarged scale, a detail which is denoted B in Figure 5.

With reference to the appended figures, 2 denotes the individual tiles used to make a floor. The tiles 2 are laid, side by side but spaced apart, on a surface with a layer of glue 7 interposed therebetween.

Laying is complete once the levelling action has been performed by means of levelling devices distributed over the entire floor during the laying stage.

In particular, each levelling device is used to act between at least two adjacent tiles 2 and comprises a base 1 which is arranged between at least two adjacent tiles 2, thereby also mutually spacing the said tiles, so as to act through contact with part of the lower surfaces of the said mutually adjacent tiles. The base 1 integrally supports an elongated body 3 which extends orthogonally therefrom. The elongated body 3 is sized so as to protrude with respect to the upper surfaces of the tiles 2 and is endowed with a stretch of thread 31 whose task is to allow the said body to be gripped from the outside. The levelling device further comprises a pressure and levelling body 4 which comprises a lower edge 40 endowed with a flat support surface 47 designed to operate through contact with at least one of the upper surfaces of the at least two adjacent tiles 2.

The pressure and levelling body 4 is freely coupled - so as to be able to rotate around the common vertical axis - with a handling unit 5 whose task is to allow the stretch of thread 31 on the elongated body 3 to be gripped from the outside. The handling unit 5 is divided into at least two parts which are elastically secured to the base but are divided in the upper area, where at least two nut screw portions 15 are formed which, once brought together in mutual contact, form a single nut screw or threaded hole 25 with which the threaded stretch 31 can be coupled. To allow proper coupling of the two nut screw portions 15, centring elements 45 and centring seats 50 are provided. The two parts 5a and 5b into which the handling unit 5 is divided are elastically secured to the base by means of two U-shaped elements positioned diametrically opposite the circular base of the said handling unit 5 which is formed as a single piece with the entire handling unit 5.

The said handling unit 5 is arranged to interact coaxially when a pressure surface 35 thereof is in contact with a corresponding support and centring surface 42 which is formed integrally with and coaxially to the said pressure and levelling body 4 in which the said surface is axially positioned and sized so as to fully bear the thrust exerted thereon at the coaxial coupling by the pressure surface 35 of the handling unit 5. The latter can therefore be freely coupled so as to rotate around the axis is common to the pressure and levelling body 4 through the mutual coupling of the pressure surface 35 and the support surface 42.

The pressure surface 35 and the support surface 42 are arranged coaxially with respect to the longitudinal axis of the handling unit 5 and to the longitudinal axis of the pressure and levelling body 4.

In particular, the pressure surface 35 is sized to couple exactly when in contact with the lateral support surface 42. Both surfaces are smooth so as to be able to mutually rotate, unhindered by anything other than friction, around the common longitudinal axis.

In particular, the pressure surface 35 consists of a portion of an "external" frustoconical surface sized to so as to couple exactly when in contact with the support surface 42, which is also shaped in such a way as to generate, overall, a portion of an internal frustoconical surface.

The lower edge 40 of the pressure and levelling body 4 has a circular shape and has axial symmetry with respect to the longitudinal axis. The said lower edge is endowed with an internal surface 41 whose task is to house, therewithin and with a guide function, an annular portion 45 located at the base 6 of the handling unit 5 upon the coupling of the pressure surface 35 and the support surface 42. The latter fulfils a function of guiding and centring the base 6 on top of the annular portion 45.

The surface 41 is delimited at the top thereof by a plurality of stop teeth 43 whose task is to curb unwanted upward movements of the handling unit 5, acting, where necessary, on the annular portion 45.

For simplicity, the entire levelling operation is described with reference to a case of two tiles 2 and can be easily schematised into the following sequence of steps.

Alongside the tile 2 placed on the layer of glue 7, the elongated body 4 is positioned in a vertical arrangement, so that the base 1 thereof is inserted into the layer of glue underneath the edge of the said tile. A new tile 2 is then laid alongside the previous one. The lower part of the elongated body 3 keeps the edge of the new tile away from the edge of the tile laid previously. The next step is to arrange the assembly consisting of the pressure and levelling body 4 with a handling unit 5 inserted therewithin on top of the upper surfaces of the adjacent tiles 2. The assembly is fitted freely onto the elongated body 3 within which the handling unit 5 is kept in the open or spread position (see Figs. 3 and 4) by means, naturally, of the U-shaped elements or springs 6. This allows the elongated body 3 to be fitted freely between the two mutually facing nut screw portions 15. The next action involves bringing the two portions of the handling unit 5 together and then sealing them, thereby making a coupling with the threaded section 31. This makes it possible to screw down the assembly immediately, tightening until the pressure and levelling body 4 is pushing against the upper surfaces of the tiles 2 and causing levelling through the counteraction exerted by the base 1 on the lower surfaces of the said tiles 2.

The coupling made between the pressure surface 35 of the handling unit 5 and the surface 42 (both of which have a frustoconical shape and make contact simply through the friction between the handling unit 5 and the pressure body 4) means that the support surface 47, with the upper surface portions of the tiles, is no longer forced to rotate without, however, penalising the necessary levelling thrust exerted on the said surfaces.

Once levelling is complete and sufficient time has lapsed for stabilisation of the assembly (for the adhesive to set), the dismantling of the assembly can be carried out by simply recovering the handling unit 5 and the pressure and levelling body 4 through the opening of the handling unit 5, which allows the immediate disengagement of the threaded coupling simply by extraction.

Subsequently, the breaking step is performed, for example by tapping with a hammer, and resulting in detachment of the elongated body 4 from the base 5, which remains in position under the adjacent tiles 1 .