EP2501519A1

EP2501519A1 - Method for smoothing-polishing surfaces of stone materials and machine associated with said method

Info

Publication number: EP2501519A1
Application number: EP09802023A
Authority: EP
Inventors: Luca Bonato
Original assignee: MBD SRL
Current assignee: MBD SRL
Priority date: 2009-11-17
Filing date: 2009-11-17
Publication date: 2012-09-26
Also published as: WO2011061765A1

Abstract

A smoothing-polishing machine is described, for slab-type products (100) made of stone material, such as marble, granite, agglomerate and the like, which comprises at least two operating heads (1) with vertical axis, assembled and radially and equally divided circumf erentially on a framework having a rotary motion around a fixed vertical axis, and that perform the smoothing-polishing operation of the slab (100) composed of an entry and an exit side and of two side edges, parallel or irregular with recesses (51); the heads (1) move along a predefined path along the slab (100) surface, with combined working motions in order to completely cover the slab (100) surface, the contact between slab (100) and heads (1) being free of interruptions along the irregular edges of the slab (100).

Description

METHOD FOR SMOOTHING-POLISHING SURFACES OF STONE MATERIALS AND MACHINE ASSOCIATED WITH SAID METHOD

The present invention relates to a method for smoothing-polishing surfaces of stone materials, ceramics, marble, granite and the like, herein below simply defined as polishing method. The present invention further relates to a smoothing-polishing machine suitable for performing the above-mentioned method .

The operations of smoothing-polishing slab-type products made of stone material are normally performed with machine tools equipped with many operating heads, equipped with abrading tools, which have the working motion, while the advancement motion is impressed to the below-placed slab to be worked.

In the current state of the art, the operating heads applied on the common smoothing-polishing machines comprise many abrading tools, equipped with an oscillating motion and radially and circumferentially arranged around the rotation axis of the operating head.

The operating heads are assembled on a framework that gives them a rectilinear reciprocating motion (working motion) with perpendicular direction with respect to the slab advancement direction.

Such construction arrangement has at least two operating inconveniences: the imperfect planarity of the smoothed surface and a very slow working speed, which result from the rectilinear reciprocating motion of the operating heads.

Object of the present invention is solving the above prior art problems, by providing a smoothing- polishing machine that allows a perfect planarity of the smoothed surface and a high working speed.

A further object of the present invention is providing a polishing method for the slab made of stone material which is able to make the slab working uniform along the whole irregular profile of the slab.

Such method consists in a combination of the continuous advanced movement of the slab with the tool motion, so that each tool-holder head, pressing on the slab surface through the tools integral therewith, moves along the slab reducing at an indispensable minimum the detachment of the tool from the slab.

This object is reached by controlling the position of the tool-carrier heads, which move along the slab profile avoiding to bump against the slab edges.

The above and other objects and advantages of the invention, as will appear from the following description, are reached with a machine and a method for smoothing-polishing surfaces made of stone material like those claimed in the respective independent claims. Preferred embodiments and non- trivial variations of the present invention are the subject matter of the dependent claims.

The present invention will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclose drawings, in which:

figures 1, 2 and 3: representation of a preferred embodiment of the machine with fixed axis suitable for polishing regular slabs of the present invention; figure 4: diagram of the interaction along an irregular edge of a tool-holder head seen by an observer placed on the fixed axis K of the machine ;

- figure 5: diagram of the interaction seguence along an irregular edge of each tool-holder head seen by an observer placed on the rotary spindle with respect to the fixed axis K of the machine during the slab advancement;

- figure 6: graphic diagram of the radial translation of a specific tool-holder head;

figure 7 : axonometric representation in orthogonal projection of a machine with tool- carrier heads actuated by an independent actuator;

figure 8: axonometric detail of the guiding support of the tool-holder head.

As ' can be seen from figures 1 to 3, the operating heads 1, arranged radially with respect to the vertical axis "K", are applied on a un chassis, globally designated with reference 2, rotating around the above axis.

In detail, every operating head 1 is supported and is sliding, through the support 3, on the guides 4, integral between the central body 5 and each one of the projecting wings 6 composing the chassis 2.

As can be seen in particular in fig. 1, the radial adjustment of the operating heads 1 is performed through threaded pins 7, which are engaged by respective supports 3, placed in simultaneous rotation through the transmission assembly 8, contained inside the central body 5, composed of two bevel gear pairs 9 and of two transmission pinions 10 and rotated through the action of the motor 11 of the transmission 12, that moves one of the above pins .

As can be seen in particular in fig. 3, the whole supporting chassis of the operating heads 1 is applied on the lower part of a cylindrical body 13, which is anchored, with points 14, on the carrier structure 15 of the machine.

The rotation of the chassis 2 and therefore of the individual operating heads 1 around the vertical axis "K" is performed by using a fifth wheel 16, interposed between the central body 5 of the moving chassis and the fixed cylindrical body 13, where the ring 17 is integral with the above cylindrical body, while the internal toothed ring 18, integral with the above central body 5, is rotated through the motor 19, equipped with the pinion 20, fastened to the base of said cylindrical body.

From what has been stated above, both the construction and the operating advantages of the smoothing-polishing machine of the invention are evident, due to the radial and symmetrical arrangement of the bodies rotating around a single axis and the chance of continuously adjusting the width "D" of the operating heads in order to adapt them to the length "L" of the slab 100 to be worked.

The above-described constructive solution is adapted to be used also by employing a single operating head, obviously associated with necessary dynamic balancing members.

The polishing method of the invention refers to the use of the above-described machine, in which every operating head 1 moves along cyclical trajectories resulting from the rotary movement around its own axis and the rotation of the structure 2 around the central axis K.

The above-described machine provides for lifting the tool-carrier heads when there are slabs having irregular edges. In fact, pneumatic means make the tool applied to the head 1 move away from the slab 100 during the head transit next to the recesses of the irregular edge of the slab; and said pneumatic means take care of restoring the tool/slab contact by following the same vertical trajectory but in reverse, when the tool is next to the slab.

The tool approaching towards the slab to be polished along an orthogonal trajectory is the single known solution to avoid that the slab edge is crushed or the diamond tool gets damaged. The limits of this method are linked to the need of having to control the impact and working pressure speed of the tool in contact with the surface of the slab 100.

The slab 100 is composed of an entry side and an exit side and of two side edges, which are parallel or irregular with recesses 51; such slab 100 is pushed along the side edges by means of a conveyor belt and is subjected to the abrading and cutting action given by the multitude of tools 1 equipped with a peripheral sped compatible with optimum abrasion and cutting parameters of the stone material. Such tools 1 move along a predefined path along the surface o the slab, and the motion imparted by the conveyor belt and the predefined path of the tools are combined in order to completely cover the surface of the slab 100: in this way, the contact between the slab 100 and the tools 1 is free of interruptions along the irregular edges of the slab 100.

A controller of the electronic type governs the detachment and the approach of the tool-holder head with respect to the slab, complying with set values of pressure and descent speed depending on the physical nature of the stone to be polished.

In the same way, one operates in case of machines with tool-holder cross-member of a hingedly moving type or oscillating transversely to the slab advancement.

An application of the polishing method of the present invention comprises a slab 100 made of stone material, with indefinite length and width H, in a continuous advancement along direction AD. A spindle 2 with maximum diameter D supports a series of tool- carrier heads 1 arranged radially with the same angular pitch. The tools are of a cylindrical shape, the circular base having a diameter d and the cylinder height being h. Spatula-type tools also fall within the scope of the method: these tools move along pendulum-type trajectories associated with the tool-holder head rotation.

The spindle 2 continuously rotates with respect to the fixed axis K perpendicular to the surface of the slab 100; the tool-carrier heads 1 rotate at a speed corresponding to the peripheral cutting speed Vp compatible with the characteristics of the material of the slab to be polished.

The number of tool-carrier heads 1, arranged radially along the circumference D of the spindle 2, is set. In this case, the tool-carrier heads are four la, lb, lc and Id. A controller C correlates data transmitted by a device S for measuring the shape of the slab 100 to be polished with: the slab advancement speed along direction AD; the rotation speed of the spindle 2 with respect to the fixed axis K; each actuator M having the task of moving radially along the guides 52 of each tool-holder head 1.

In particular, the controller C rebuilds the shape of the slab 100 and correlates the angular position of each tool-holder head 1 with the position of the slab 100 along the translation plan depending on the advancement speed of the slab 100. A Cartesian map x2, y2 seen by an observer placed on the spindle 2 rotating with respect to the fixed axis K, associates the profile of the edge of the slab 100 to each tool-holder head la, lb, lc and Id. A dedicated protocol, connected to the controller C, manages the interaction of the profile of the slab 100 with respect to the size of the tool with diameter d integral with the tool-holder head 1. For every tool-holder head la, lb, lc and Id, the software rebuilds the interaction with respect to the recessed edge 51, computing the value of arm R depending on the recessed edge 51. The thereby collected data are used to control every actuator M, which changes the radial position of each tool- holder head la, lb, lc and Id.

With this polishing method and the related machine associated therewith, the objective is reached of making the vertical movement of the tool- carrier heads minimum. In fact, each actuator M connected to the tool-holder head 1 ensures that the tool is kept inside the edge of the slab 100 independently from the geometric shape and therefore the presence of the recesses 51. This arrangement removes every sort of manual adjustment in order to adapt the working distance D to the width H of the slab 100.

The tool detachment from the slab 100 is limited to the entry and exit steps of the slab 100, namely to the lower and upper edges of the slab 100.

The machine is further equipped with a single actuator connected to the spindle 2 which vertically moves the spindle 2 depending on the slab thickness.

A simplified version of the machine of the invention provides for the use of a single actuator for the radial movement of the heads 1.

The machine used for reaching the described object is simplified from the construction point of view, having removed the connection and reduction assemblies 8 and 10.

Claims

1. Smoothing-polishing machine for slab-type products (100) made of stone material, such as marble, granite, agglomerate and the like, said machine being characterised in that it comprises at least two operating heads (1), of a type with vertical axis, which are assembled, radially arranged and equally divided circumferentially, on a framework having a rotary motion around a fixed vertical axis, said operating heads (1) being adapted to perform a smoothing-polishing operation of the slab (100), said slab (100) being composed of an entry side and an exit side and of two side edges, parallel or irregular with recesses (51), said slab (100) being adapted to be pushed along the side edges by means of a conveyor belt and being subjected to an abrading and cutting action imparted by the operating heads (1) having a peripheral speed compatible with abrasion and cutting parameters of the stone material, said heads (1) moving along a predefined path along the surface of the slab (100) , said motion imparted by the conveyor belt and said predefined path of the heads (1) being combined in order to completely cover the surface of the slab (100) , the contact between said slab (100) and said heads (1) being free of interruptions along the irregular edges of the slab (100).

2. Smoothing-polishing machine according to claim 1, characterised in that every operating head (1) has a planetary motion resulting from two movements: a rotation movement around its own axis and a rotation movement around the central axis of a supporting structure of all operating heads (1) applied on the machine.

3. Smoothing-polishing machine according to claim 2, characterised in that said operating heads (1) have a radial opening adapted to be adjusted in order to adapt a working area (D) of the heads (1) to the width (L) of the below slab (100) to be smoothed- polished .

4. Smoothing-polishing machine according to any one of the previous claims, characterised in that the operating heads (1) are radially arranged with respect to the vertical axis (K) and are applied on a chassis (2) rotating around the vertical axis (K) .

4. Smoothing-polishing machine according to claim 3, characterised in that every operating head (1) is supported and is sliding, through a support (3) , on guides (4), integral between a central body

(5) and each one of projecting wings (6) composing the chassis (2 ) .

6. Smoothing-polishing machine according to claim 5, characterised in that a radial adjustment of the operating heads (1) is performed through threaded pins (7), which are engaged by the respective supports (3) , said pins (7) being simultaneously rotated through a transmission assembly (8), contained inside the central body (5) and composed of two bevel gear pairs (9) and two transmission pinions ( 10 ) .

7. Smoothing-polishing machine according to claim 6, characterised in that the transmission assembly (8) is adapted to be rotated through the action of a motor (11) and a transmission (12), that move one of the threaded pins (7) .

8. Method for smoothing-polishing surfaces of stone materials, adapted to work at least one slab (100) composed of an entry side and an exit side and of two side edges, parallel or irregular with recesses (51), said slab (100) being pushed along the side edges by means of a conveyor belt and being subjected to an abrading and cutting action imparted by a multitude of tools having a peripheral speed compatible with abrasion and cutting parameters of the stone material, said tools moving along a predefined path along the surface of the slab, said motion imparted by the conveyor belt and said predefined path of the tools being combined in order to completely cover the surface of the slab, characterised in that a contact between said slab (100) and said tools is free from interruptions along the irregular edges of the slab (100) .

9. Method for smoothing-polishing surfaces of stone materials according to claim 8, characterised in that an interruption is allowed of the contact between tool and slab (100) in the entry and exit steps of the slab (100), namely next to the upper and lower edges of the slab (100).

10. Method for smoothing-polishing surfaces of stone materials according to claim 8 or 9, characterised in that the method is performed through a machine according to claim 1, in which an actuator (M) connected to a tool-holder head (1) moves its related tool-holder head (1) along a radial distance (R) depending on a position of the tool-holder head (1) with respect to the profile or edge of the slab (100), during the advancement of the slab (100) along a direction (AD) and during a rotation of the spindle (2) with respect to a fixed axis (K) .

11. Method according to claim 10, characterised in that the actuator (M) controls the radial movement of the tool-holder head (1) along sliding guides (52) .

12. Method according to claim 11, characterised in that a vertical movement of the tool-carrier heads (1) occurs only if the tool-holder head (1) interacts with the lower and upper edges of the slab (100) ..

13. Method according to claim 11, characterised in that the actuator (M) connected to the spindle (2) regulates an height of said spindle (2) depending on the thickness of the slab (100) .