AND RELEVANT WORK HEAD" Technical Field of the Invention

The present invention relates to a machine for working the surface of ceramic products and to a relevant work head.

In particular, the present invention is mainly applicable for surface finishing operations such as polishing, lapping and honing, on various kind of ceramic products. State of the Art

As it is known, ceramic products like tiles and bricks, for example, are worked in correspondence of a respective exposed surface by means of suitable work tools.

Such tools are made up of rollers whose external cylindrical surface is capable of lapping the ceramic product's surface. In general, the tools are supported by a work head disposed above a belt conveyor intended to feed a series of ceramic products.

In particular, developing above the belt conveyor is a horizontal crossbeam under which the above mentioned head - suitably motorized to drive the rollers held therein into rotation - is made to project .

In this way, the products are fed below the crossbeam and intercepted by the rollers to be suitable worked by the latter. Generally, the crossbeam supports a series of heads, located close to each other and each of which being provided with suitable rollers for a given machining.

Accordingly, the surface of each ceramic product is made to pass in succession under each head to receive a series of diversified specific works according to the type of operating tool.

The work machine and respective tool-holding heads exhibit, however, a major drawback.

Such drawback is given by the fact that the rollers are not able to provide a homogeneous work over the whole surface of the products to be worked. It is to be pointed out, in fact, that the side ends of the roller generate regions of the products which are not sufficiently worked. Accordingly, side portions result onto the product surface being worked which are dishomogeneous in comparison with a respective central portion.

Description of the Invention

In this context, the technical task on which the present invention is based is to propose a machine for working the surface of ceramic products, and a relevant work head able to overcome the above indicated drawbacks of the prior art.

In particular, the object of the present invention is to provide a machine for working the surface of ceramic products and a relevant work head capable of working homogeneously the whole surface of respective ceramic product in the course of formation. A further object of the present invention is to provide a machine for working the surface of ceramic products and a relevant work head structurally simple and able to improve the polishing and honing action on ceramic products . The indicated technical task and specified objects are substantially achieved by a machine for xvorking the surface of ceramic products and relevant work head, comprising the characteristics set forth in one or more of the attached claims . Further characteristics and advantages of the present invention will appear more clearly by the indicative and non-limitative description of a preferred but non-exclusive embodiment of a machine for working the surface of ceramic products and of a relevant work head, as illustrated in the accompanying drawings, wherein: - Fig. 1 is a perspective and schematic view of a machine for working the surface of ceramic products according to the present invention;

- Pig. 2 is a perspective view of a work head, according to the present invention, used in the machine of Fig. 1;

- Fig. 3 is a perspective view with some parts taken away for best showing other parts of the work head of Fig. 2; - Fig. 4 is a side elevation view with some parts taken away for best showing other parts of the work head of Fig. 2; and

- Fig. 5 is a front elevation view sectioned on line V-V of Fig. 2 of the work head according to the present invention.

Referring in particular to Fig. 1, numeral 1 indicates in the whole a machine for working the surface of ceramic products 2, according to the present invention. The machine 1 is especially used for surface finishing operations of at least one ceramic product 2, shown schematically in Fig. 1, such as a tile, for example . Said finishing operations may be, for example, a polishing, honing, or grinding of at least one surface 2a being worked of the said product 2. As illustrated in Fig. 1, the machine 1 comprises a support member 3 supporting at least one ceramic product 2 to be treated and able to feed the same product 2 along a respective feed direction "A".

Preferably, the supporting member 3 is provided with a belt conveyor having a feeding surface 4 movable along the said direction ^λX A", to feed a series of products 2 in succession. Developing above the support member 3 is a horizontal crossbeam 5, suitably supported by respective vertical stays 6. The crossbeam 5 has a longitudinal development parallel to said feed direction "A" and is able to support at least one work head 7 to be described herebelow in greater detail.

Preferably,- the crossbeam 5 supports a plurality of work heads 7 facing the feed surface A and acting onto the surface 2a to be worked of products 2. Advantageously, the work heads 7 are associated with a lower portion 5a of the crossbeam 5 and are disposed close to each other to form a row of heads running along the longitudinal development of the same crossbeam 5. Each work head 7 can be predisposed for a specific machining to be carried out on the product's surface 2a. In this way, as the product 2 moves forward, it is subjected, in correspondence of each head 7, to a different machine operation.

For example, the heads 7 can provide for operations of progressive finishing in which each product 2, as it meets the respective heads 7, is subjected to 'an increasingly fine machining onto the respective surface 2a.

The machine 1 also comprises a plurality of motors 8 - not to be described in detail as they are of known type and make no part of the present invention - engaged with an upper portion 5b of crossbeam 5.

In this way, the motors 8 result disposed on a side opposite to the respective heads 7 , Each motor 8 is suitably associated with a main shaft

9 of a respective head 7, to drive the same shaft 9 into rotation about the respective longitudinal axis ^λΛ X" .

In particular, as best illustrated in Figs. 2, 3 and 5, the work head 7 comprises a support frame 10 having a substantially box-like shape defined by respective side walls 10a.

Developing inside the frame 10 is at least one work tool 11 operatively associated with the side walls 10a and projecting at least partially out of a lower aperture 12 of same frame 10.

In greater detail, and with reference in particular to Fig, 5, the work tool 11 consists of a roller 11a having a substantially cylindrical shape and developing along a first longitudinal axis ^λV Y".

The roller 11a exhibits a cylindrical surface 13, suited for working the surface of product 2, and respective opposite ends 13a rotatively associated with the side walls 10a. It should be noted that the cylindrical surface 13 projects partially out of the above said lower aperture 12 in order to act onto the product 2 being made to advance below the head 7. Advantageously, the head 7 is provided with two work tools 11, respectively disposed close and parallel to each other.

The head 7 further comprises first driving means 14 inside the frame 10, which are operatively associated with the work tools 11 to rotate the latter about the relevant first axis ^λN Y". More in particular, and as illustrated in the sectional view of Fig, 5, the main shaft 9 extends, at least partially inside the frame 10, to be operatively engaged with the first driving means 14. It should be noted that the main shaft 9 has a first end 9a housed inside the frame 10, and a second end 9b outside the frame 10 to be operatively associated with the respective motor 8. In this situation, the first driving means 14 are engaged with the second end 9b of shaft 9 to drive each tool 11 into rotation about the first axis "Y".

Preferably, the first driving means 14 consist of a transmission shaft 15, extending parallel to the first axis "Y" and to said tools 11. The transmission shaft 15 has a first end 15a on which a first bevel gear 16 is fitted, and a second end 15b opposite to the first 15a.

The first bevel gear 16 is suitably caused to mesh with a second bevel gear 17 keyed on the first end 9a of main shaft 9. In this way, the rotary motion of main shaft 9 is transferred to the transmission shaft 15.

Fitted in correspondence of the second end 15b of the transmission shaft 15 is a first toothed wheel 18 (Figs, 4 and 5), which is rotated by the same shaft 15 about a respective axis parallel to the first axis

Referring now in particular to Fig. 4, it can be noted that, on opposite sides of the first toothed wheel 18, there are provided two second toothed wheels 19 meshing with the said first toothed gear 18 and each being keyed to a respective work tool 11.

In fact, each roller 11a exhibits, in correspondence of one end 13a, a respective second toothed gear 19 able to transfer the rotary motion from the first wheel 18 to the tool 11.

In this way, the main shaft 9 provides for the rotation of said work tools 9 about the first axis

The head 7 further comprises second driving means 20 opBrHt±ve±y associable with the support frame 10 to rotate the work tools 11 about a second axis "X" perpendicular to the first axis "Y" and corresponding to the axis of longitudinal development of the main shaft 9. Advantageously, the second driving means 20 impose a reciprocating motion, according to arrow "B" of Fig. 2, to the whole frame 10 and, consequently, to the first driving means 14 and tools 11 held within the frame 10. In particular, the second driving means 20 comprise a cam device 21, associated with the frame 10 to move the latter about the second axis "X", and a transmission member 22 between the main shaft 9 and the cam device 21 to transfer the rotary motion. In greater detail, as shown in Pig. 3, the cam device 21 exhibits a toothed wheel 23, rotatively associated with an upper wall 10b of frame 10, opposite to said lower aperture 12.

The toothed wheel 23 can be rotated about a respective axis parallel to said axis "X" and is provided with an eccentric pivot 24 projecting above the same wheel 23.

The cam device 21 exhibits also a link block 25 (Fig. 2) removably associated with the frame 10 and having a guide 26 for receiving the eccentric pivot 24.

In particular, the link block 25 exhibits a plate 27 mounted on top of frame 10 and provided with a central hole for the main shaft 9 to go through. The plate 27 also exhibits a coupling portion 28, projecting above the same plate 27 to be rigidly engaged with said crossbeam 5 of the machine 1 above described. In fact, as illustrated in Fig. 1, a tubular body 29 extends from the crossbeam 5 for engagement with the coupling portion 28. In this way, during the operation of head 7, the plate 27 remains fixed to the crossbeam 5, while the said frame 10 is free to move about the second axis "X" , It is pointed out that the coupling portion has an annular projection, extending concentrically and about the second end 9b of main shaft 9. It is also to be noted that the housing guide 26 is defined by a straight slot formed in the plate 27 and inside which the eccentric pivot 24 can slide. In this way, the action inside the guide 26 of pivot 24 - the latter, during its rotation, sliding within the slot with a rectilinear and alternate motion - drives the whole frame 10 into a reciprocating motion about the second axis ^λ 'X". Such action is due by the stable constraint of link block 25 fixedly mounted onto the crossbeam 5, thereby determining the displacement of the whole frame 10 and all members held and supported therein. Advantageously, the transmission member 22 comprises at least a toothed wheel 30 meshing with the toothed wheel 23 and with a toothed surface 31 formed in the main shaft 9.

Preferably, two toothed wheels 30 are present, suitably associated with each other to transmit the motion of the main shaft 9 to the toothed wheel 23 of the cam device 21.

The action of the cam device 21, which transforms the rotary motion of the shaft 9 into an oscillatory, reciprocating motion of frame 10, also drives the tools 11 into motion about the second axis "X". Consequently, the tools 11 are both made to rotate about the respective longitudinal axis and to translate about the second axis ^Λλ X",

Consequently, the machining of products 2 results more homogeneous over the whole surface 2a in the course of formation.

Actually, by driving the rollers 11a about the second axis "X" there is avoided the formation of portions worked to a more or less degree than others. In fact, in this way, the side portions of rollers lla are made to act on the whole surface 2a of the products 2.

It should also be considered that the combined motion of the tools 11 improves the lapping action, thereby finishing more efficiently the surface to be worked 2a of each product 2.

In a second embodiment, the crossbeam 5 has a rectilinear, alternate motion perpendicular to the work direction "A" so as to achieve, on the product under work, the combined effect of said alternate motion and that generated by the heads 7 on rollers 11, as above described.

This combination of motions makes it possible to achieve a more uniform and planar machining, with a consequent improved product quality and a significant reduction of lack of uniformity in the wear of rollers 11.

In the embodiment in which also the crossbeam 5 moves with reciprocating motion perpendicularly to the work direction "A", it is possible to achieve even a more uniform machining, as this is combined with the above described motion of the rollers associated with the respective heads 7.

Moreover, by the translatory motion of crossbeam 5, on which the heads 7 are mounted, it is possible to work tiles 2 of any shape without the need every time of changing the rollers, which is a very complex operation.