The invention relates to an improved automatic control machine intended to be used in the ceramic industry.

The invention particularly relates to an automatic machine which was devised for carrying out the so-called "selection" of flat ceramic articles, such as ceramic tiles or slabs.

Even more in detail, the invention refers to a machine which is predisposed for performing, on the tiles, at least a geometric control (or "linear measurement"), as well as a flatness control.

There are known machines which are suitable to perform a sorting function based on which ceramic tiles or slabs are sorted out or discarded.

In detail, the sorting machines may be located upstream of end stations, wherein the tested articles are separated, thereby forming homogeneous groups or, as is usually said, the tested articles may belong to the same "selection group".

There are further known automatic control machines which are able to perform both a dimensional/geometrical control as well as an aesthetic control, in the sense of providing to perform checkings on tone and defects of the articles.

The control machines comprise a cabin, wherein the optical control devices are located and a conveyor which passes through the cabin and essentially consists of two parallel belts driven by respective motors. The two belts support the articles and convey them continuously within the cab, wherein they are tested and thereafter conveyed towards the end of line, downstream of the machine.

The two belts are movable horizontally such that the reciprocal distance may be adjusted based on the different sizes of the articles to be tested. Although the known machine has proven to be able to function effectively, the same is not entirely free of drawbacks, especially when used to perform control of very long and slim tiles, which are having a great commercial deployment in the last time. A first drawback relates to the flatness control of ceramic articles, in particular tiles.

This control is aimed at checking flatness of the tested tile following laying thereof on floors or coverings.

When freely resting on the conveyor belts, the tiles, especially slim and long sized tiles as already mentioned, tend to bend due to gravity.

This circumstance constitutes a factor which distorts the flatness measurements performed by conventional machines.

Furthermore, the known conveyor system requires the perfect parallelism of the two belts, in that, even mild convergences or divergences have the effect of producing a rotation of the tiles during transport, which affects the reliability of the measurements performed by the machine.

The perfect parallelism of the belts is very complex to achieve, and above all, to maintain.

Indeed, on the one hand, achievement of parallelism requires complex installation and adjustment operations and, on the other, once obtained, the parallelism is rapidly lost due to the stresses the belts are subjected to during use and, due to the repeated movements away and towards, referred to above.

These drawbacks are exacerbated by the fact that the two belts may be activated independently from one another, since each of them is driven by a respective motor.

Therefore, in the absence of a perfect synchronization of the two motors, which is complicated to achieve and difficult to maintain, it takes place a rotation or a slipping of the tile which is being conveyed on the belts, resulting in inaccuracies of the measurements performed.

In this context, the technical task at the base of the present invention is to provide a control machine which overcomes the drawbacks of the known art mentioned above.

The technical task mentioned is attained by the control machine realized in accordance with claim 1 . Further characteristics and advantages of the present invention will become more apparent from the indicative, and therefore non-limiting description of a preferred but non-exclusive embodiment of the control machine illustrated in the appended figures wherein:

- Figure 1 is a view in vertical section of the machine according to the proposed invention; and

- Figure 2 is a schematic top view of the machine of Figure 1 . With reference to the appended figures, by 1 it is generically indicated a control machine for flat articles 2, such as ceramic tiles or slabs, which control machine constitutes the object of the present invention.

As already mentioned above in the discussion on the prior art, the machine 1 herein provided is intended to perform control operations automatically.

In detail, the machine 1 includes a control section 10 (shown in Figure 2) provided with control means 1 1 , 12 suitable for performing at least measurements of the geometric type (or "linear measurement"), as well as flatness measurements on flat articles 2.

Preferably, the control means 1 1 , 12 is of the type suitable to perform also aesthetic checkings on the articles 2 tested.

For the sake of descriptive simplicity and without loss of generality, reference will be made hereinafter to the exemplary case in which the flat articles tested are tiles 2.

The machine 1 comprises conveyor means 3, 4, 5, 6 for continuously conveying the tiles 2 to be tested towards the above-mentioned control section 10, and thereafter toward the output of the machine 1 .

According to an important aspect of the invention, the conveyor means comprises a conveyor belt 3 suitable to support and move the tiles 2. In particular, the proposed machine 1 comprises a belt 3 which defines a continuous conveyor belt, whereon the tiles 2 to be tested are laid, one after the other.

The belt of the invention is thus capable of conveying the tiles in an advancement direction D, parallel to the axis of the longitudinal development of the machine itself.

Even more in detail, the invention preferably comprises a single conveyor belt 3 which is able to convey alone the tiles 3.

Preferably, the width of the belt 3 defines the maximum transverse dimensions of the conveyor means, possibly not including the input and output ends of the machine 1 ; this aspect shall be better detailed in a later section.

A cab 13 is mounted at the control section 10, in which cab 13 there is located the control means 1 1 , 12 mentioned above.

As shown schematically in Figure 1 , the control means preferably includes optical devices (such as cameras 1 1 and laser projectors 12), pointing in the direction of the belt 3, i.e., towards the horizontal plane 31 on which the tiles 2 are passing one after the other.

The control means may further include a processing unit for managing the optical devices 1 1 , 12 and processing the acquired images in order to perform control and provide the results of performed calculations to the operator.

In this configuration, the belt 3 defines a kind of movable "floor" of the cabin 13.

As shown in the accompanying figures, the conveyor means comprises two opposite pulley means 4, 5, respectively arranged at the input I and the output U of the machine 1 .

Such pulley means may be constituted e.g. by rollers 4, 5 or similar rotatable elements.

The belt 3 of the invention, is closed in a loop around the two pulley means 4, 5 already mentioned, thereby defining two parallel and horizontal planes 31 , 32.

The horizontal movable conveyor belt, whereon the tiles 3 are restingly lying, is constituted by the upper surface 31 of the belt 3.

This upper surface 31 is crossing aforesaid control section 10, by entering and exiting the cab 13 through appropriate openings.

In the preferred embodiment of the invention, the conveyor means comprises two guide rollers 4, 5 in all, rotatable about the axes which are parallel to one another and horizontal, which guide rollers 4, 5 are placed in opposite positions along the longitudinal development of the machine 1 . One of these rollers 4, for example the one arranged at the output U, is set in rotation by a suitable motor 6, while the other roller 5 is preferably idler. Note that, as shown in Figure 1 , the invention may provide use of a backlight 14 arranged in the control section 10, below the upper surface 31 of the belt.

Preferably, the width of the belt 3 is equal to or greater than the maximum width of the tiles 2 to be inspected.

In general, as mentioned above, the width of the conveyor belt 3 defines the maximum transverse dimensions of the conveyor means, at least in the portion comprised between the two pulley means 4, 5.

An alternative embodiment is however not to be excluded, wherein, albeit the belt 3 has a width less than that of the tiles 2 to be tested, this width is sufficient to allow conveyance of the tiles 2.

The advantages of the proposed invention are listed below.

The conveyor belt 3 of the machine 1 , which extends to the whole width with respect to the conveying zone, supports the tiles 2 by coming in contact with the entire bottom surface, or in any case a preponderant portion thereof.

Thus, the tile 3 is resting on a continuous horizontal plane 31 , which completely prevents or greatly limits the effects of gravity on the flatness of the tiles 2 conveyed, i.e., that kind of bending effect which, tends to distort flatness measurements in the prior art.

Hence, the invention is able to perform reliable flatness measurements even in relation to long and slim tiles referred to above.

Additionally, the fact of providing a single conveyor belt 3 instead of the two belts of the prior art, allows to overcome all of the drawbacks due to use of a plurality of independent conveyor elements.

In particular, owing to the control machine 1 of the invention, the tiles 2 may translate without being subjected to any rotations which in the prior art are due to imperfect parallelism of the belts.

Similarly, given that the operation of the machine herein disclosed is based on a single motor 6 which drives the conveyor belt 3, the machine is not subject to any synchronization problems which instead affect the two motors associated with the two belts of the known machines.

Additionally, the fact that a single conveyor belt 3 was provided, makes it possible to avoid the complication of having to move forward or away the belts according to the different sizes of the tiles 2 to be tested.

Finally, the machine 1 of the invention of course includes a support base 7 consisting of a pallet or the like and may include additional devices and components the control machines are usually provided with.