DEVICE FOR CALIBRATING THE POSITION OF SHEET-LIKE ELEMENTS AND RELATIVE MACHINE FOR GRINDING SHEET-LIKE ELEMENTS

Technical field

This invention relates to the field of machining slabs, for example tiles, made from ceramic material, stone, glass or the like. In particular, the invention relates to a device for calibrating the position of sheet-like elements and relative machine for grinding sheet-like elements.

It is known that the slabs produced industrially and which can be used as tiles for flooring and other types of covering require a grinding operation. The main aim of this grinding operation is to guarantee the mutual orientation of the sides in such a way as to allow the placing alongside of the various slabs without clearance.

Background art

In the field of the industrial production of slabs this operation is carried out by means of grinding machines which are able to quickly process large quantities of ceramic products which feed in succession on a horizontal movement plane.

The sides of the products to be processed protrude laterally and come into contact with a succession of grinding wheels, which remove the excess material and move the outer perimeter flush and, if necessary, one or more inclined grinding wheels, for performance of the chamfering operation.

In commonly used machines, the grinding of the slabs is performed in two steps.

In a first step, they are ground by specific grinding wheels facing each other facing the movement plane on two opposite sides of each slab.

The slabs are then rotated by 90° in such a way that the two remaining sides can be ground by further grinding wheels facing and alongside the movement plane. In order to be able to guarantee the mutual perpendicularity between the sides which are to be ground in the first step and the sides which are to be ground in the second step, the machines for grinding slabs have special positioning means which, after the rotation of the slabs, adjust the orientation on the movement plane in such a way that the sides already ground are perpendicular to the orientation of the subsequent grinding wheels.

For this purpose, the prior art teaches the use of the linear pushing elements located above the movement plane which, simultaneously with the passage of each slab, are lowered and transferred horizontally in an independent fashion so as to come into contact with the rear edge of the latter in such a way as to adjust the orientation.

A solution of this kind is described in document WO201 1 1 10907A1 .

Disadvantageously, the kinematic mechanism linked to the movement of these pushing elements is complex and the movement mechanism is complex and requires a large number of movement units.

Aim of the invention

In this context, the technical purpose which forms the basis of this invention is to provide a device for calibrating the position of sheet-like elements and relative machine for grinding sheet-like elements which overcomes at least some of the above-mentioned drawbacks of the prior art.

In particular, the aim of the invention is to provide a device for calibrating the position of sheet-like elements and relative machine for grinding sheet like elements which is an alternative to and more efficient than the prior art, with regard to the mechanism for moving the pushing elements.

The technical purpose indicated and the aims specified are substantially achieved by a device for calibrating the position of sheet-like elements and relative machine for grinding sheet-like elements comprising the technical features described in one or more of the accompanying claims.

The dependent claims correspond to possible embodiments of the invention. Further features and advantages of the invention are more apparent in the non-limiting description which follows of a preferred embodiment of a machine for grinding slabs.

Brief description of the drawings

The description is set out below with reference to the accompanying drawings which are provided solely for purposes of illustration without restricting the scope of the invention and in which:

- Figure 1 shows a perspective view of a device for calibrating the position of sheet-like elements made according to the invention;

- Figure 2 shows a different perspective view of the device of Figure 1 ;

- Figure 3 shows a different perspective view of the device of Figure 1 ;

- Figure 4A shows an enlargement of a detail of Figure 1 indicated with reference IVa;

- Figure 4B shows an enlargement of a detail of Figure 2 indicated with reference IVb;

- Figure 4C shows an enlargement of a detail of Figure 2 indicated with reference IVc;

- Figure 4D shows an enlargement of a detail of Figure 3 indicated with reference IVd.

Detailed description of preferred embodiments of the invention

A device for calibrating the position of sheet-like elements on a conveyor, which is the object of the invention, is illustrated in the accompanying drawings and denoted generically with reference numeral 1. This will be referred to below as“device 1

Another object of the invention is a machine for grinding sheet-like elements which comprises the device 1.

The device 1 in accordance with the invention comprises a supporting frame 10 which can be connected to the above-mentioned machine for grinding sheet-like elements. The supporting frame 10 extends about a space“5 V” configured for housing a conveyor directed towards the machine for grinding sheet-like elements to which it is connected or connectable, for example according to a gantry type configuration.

The supporting frame 10 has one or more transversal guides 15, in particular two transversal guides 15, overlying, in a use configuration, the space“V” in an architrave configuration.

In particular, the transversal guides 15 are positioned and/or configured so as to be oriented perpendicularly to the conveyor directed towards the machine for grinding sheet-like elements.

The device 1 also comprises two longitudinal guides 20, parallel to each other and perpendicular to the transversal guide 15, connected to the transversal guides 15 so as to overlay in a configuration of use the space “V” and, in particular, the above-mentioned conveyor.

The longitudinal guides 20 are slidably connected to the transversal guides 15 in such a way as to be movable along them towards and away from each other.

The longitudinal guides 20 are movable towards and away in a parallel direction to the transversal guides 15.

In a use configuration, the longitudinal guides 20 are oriented in a direction parallel to the conveyor and mobile in a direction perpendicular to it.

The device 1 also comprises two rotary adjustment shafts 25, parallel to each other and oriented perpendicularly to the longitudinal guides 20 and therefore parallel to the transversal guides 15).

Each adjustment shaft 25 engages both the longitudinal guides 20 in such a way that simultaneous rotations of said adjustment shafts 25 results in respective translations towards or away from the longitudinal guides 20 along the transversal guides 15.

Preferably, each adjustment shaft 25 engages both the longitudinal guides 20 by means of respective couplings 26 designed to transform a rotary motion about an axis into translational motion along the same axis. In particular, these couplings 26 are of the screw-nut or recirculating ball type and defines spirals of opposite directions to each other so that a same rotation of the adjustment shaft 25 defines translations of same direction and opposite sense of the longitudinal guides 20.

Preferably, the adjustment shafts 25 have a reciprocal distance of between 250 mm and 2500 mm.

Moreover, the adjustment shafts 25 and the transversal guides 15 allow translations towards or away from the longitudinal guides 20 between a maximum distance of 3500 mm and a minimum distance of 100 mm.

The device 1 also comprises a first actuator 27 of the rotary type, preferably an electric motor, connected by a kinematic mechanism to the adjustment shafts 25 to transmit to them a rotary movement, preferably with the same direction and angular speed.

Each adjustment shaft 25 has a respective transmission pulley 29 at a relative end, the transmission pulley 29 being integral with the structure of the adjustment shaft 25.

Moreover, the first actuator 27 has a respective transmission pulley 29 positioned close to the transmission pulleys 29 of the adjustment shafts 25, preferably such that three transmission pulleys 29 are positioned at respective vertices of an isosceles triangle.

Preferably, the device 1 comprises a distribution belt 28 fitted on the transmission pulleys 29 in such a way as to transmit the rotary movement from the first actuator 27 to the adjustment shafts 25.

In the preferred embodiment, the distribution belt 28 and the transmission pulleys 29 have a toothed coupling.

Preferably, the device 1 comprises a plurality of idle pulleys 30 (or idle rollers) connected to the supporting frame 10 and configured for defining a closed-loop path of the distribution belt 28 between the transmission pulleys 29 wherein the distribution belt 28 performs a curve greater than 135°, preferably greater than 180°, about each transmission pulley 29 of the adjustment shafts 25 and of the first actuator 27. Preferably, the plurality of idle pulleys 30 comprises two idle pulleys 30a positioned outside the closed path and the distribution belt 28 forming respective concave curvatures of the distribution belt 28 and an idle pulley 30b positioned inside the closed path and forming a convex curvature of the distribution belt 28.

The device 1 further comprises two pushing elements 35, configured for adjusting the orientation of the sheet-like elements on the conveyor.

Each pushing element 35 comprise a carriage 36 and an arm 37 having an end hinged to the carriage 36 and a free end.

The carriage 36 is connected to a respective longitudinal guide 20 and slidable along it between a withdrawn position and an advanced position. The arm 37 is rotatably movable to and from the space“V” between an engaged position and a disengaged position, preferably about an axis perpendicular to the longitudinal guides 20.

In the disengaged position, the free end of the arm 37 s positioned in a lowered position and configured for making contact with a perimeter edge of a sheet-like element positioned on the above-mentioned conveyor during a translation of the pushing element 35 from the advanced position to the withdrawn position.

In the disengaged position the free end is positioned in a raised position and configured for allowing the of a sheet-like element on the conveyor towards the machine for grinding sheet-like elements without interfering with them. Preferably, each pushing element 35 comprises a removable contact plug 38, connected at the free end of each arm 37 in such a way that it makes contact with a perimeter edge of a sheet-like element positioned on the conveyor when the arm 37 is in an engagement position during a translation of the pushing element 35 from the advanced position to the withdrawn position.

The device 1 also comprises a drive mechanism configured for moving the carriages 36 along the longitudinal guides 20 between the withdrawn position and the advanced position. Preferably, the drive mechanism comprises a single translation actuator 39 kinematically connected to both pushing elements 35 for simultaneously moving the carriages 36 between the advanced position and the withdrawn position.

Moreover, the actuation mechanism preferably comprises a rotary shaft 40 connected by a kinematic mechanism to the translation actuator 39 and positioned perpendicularly to longitudinal guides 20 so as to engage both of them.

The longitudinal guides 20 are configured to slide along the rotary shaft 40 in a direction parallel to the relative axis of rotation during their movement towards and away from each other.

The rotatable shaft 40 is connected to the longitudinal guides 20 so as to transmit drive to the carriages 36.

The device 1 also comprises a control unit electrically connected to sensors for detecting the orientation of the sheet-like elements described above and configured for actuating the pushing elements (35) so as to correct the orientation of the sheet-like elements.

The machine for grinding sheet-like elements, which is also an object of the invention, comprises:

a main frame;

- a conveyor configured for moving a plurality of sheet-like elements along a feed direction from an infeed station to an outfeed station;

- a plurality of grinding wheels connected to the main frame and facing the conveyor between the infeed station and the outfeed station and configured for grinding said sheet-like elements positioned on the conveyor;

- a device 1 for calibrating the position of sheet-like elements of the type described above, connected to the main frame upstream of the plurality of grinding wheels in such a way that the longitudinal guides 20 are oriented parallel to the feed direction.

Preferably, the conveyor extends in the space“V” defined by the supporting frame 10 of the device 1 and the end of each arm 37 is configured for making contact against a perimeter edge of a sheet-like element positioned on the conveyor when the arm 37 is in an engagement position during a translation of the pushing element 35 from the advanced position to the withdrawn position.

The invention achieves the set aim by overcoming the drawbacks of the prior art.

In fact, the solution described defines an effective alternative to the prior art solutions and it is simpler and more efficient to perform the movement.