™ooo — The present invention relates to an apparatus with orbital movement for cutting stone material and the like on paths, in particular circular, defined by the operator.

It is known that cutting stone material and the like on closed, in particular circular, paths presents considerable difficulties.

In the state of the art, the cutting of circular holes or circular discs in marble, glass and the like is carried out by means of holes which are close together and of limited dimensions with cylinder-type diamond-coated milling cutters. This technique requires a different milling cutter for each diameter of hole to be cut, which involves a large stock of costly tools and, as mentioned above, limits on the diameter of the holes or discs cut. Furthermore, with the tools according to the prior art, contourings and other finishes cannot be effected without having the same number of series of specialized tools available.

The aim of the present invention is to provide an apparatus of the type mentioned which makes it possible to carry out with ease, working with orbital movement, circular cuts in particular, eliminating the disadvantages of the prior art.

According to the present invention, the apparatus comprises a base which can be anchored in a releasable manner to a slab of stone material being worked, said base being arranged to support in a rotatable manner a platform in which there is supported a pair of orthogonal slides which are radially and vertically movable subject to commands for advance and positioning. The pair of slides supports a motor associated with a spindle with a vertical axis arranged to support and make a cutting and/or working tool rotate in a position at a predeterminable radial distance, and with adjustable lowering. Also provided are means to make the platform rotate to describe an orbital movement along a path centred on the axis of symmetry of the platform mounted in rotatable manner on the base.

According to the present invention, means are also provided for expanding the operational capacities of the apparatus concerned, according to the attached dependent claims.

The present invention will now be described with reference to a currently preferred embodiment, given by way of non-limiting example and on the basis of the figures of the attached drawings, in which:

Figure 1 shows a method of working for cutting circular holes or circular pieces from a slab of stone material and the like according to common prior art;

Figure 2 shows diagrammatically the methods of working of the apparatus according to the invention for cutting circular holes or circular pieces from a slab of stone material and the like;

Figure 3 shows a lateral overall view of the apparatus according to the invention;

Figure 4 shows a plan view from above of the apparatus in Figure 3;

Figure 5 shows a partial lateral view of the apparatus in Figure 3 looking in the direction of the arrow FI;

Figure 6 shows a partial lateral view of the apparatus concerned looking at 90° in relation to Figure 5;

Figure 7 shows a diagrammatic view in longitudinal section essentially on the plane IV-IV in Figure 4 which illustrates the arrangement of component parts not visible in Figures 3 to 6;

Figure 8 shows an alternative to the construction according to the invention as illustrated in Figures 3 to 7;

Figure 9 shows a front view of the construction in Figure 8 coupled to a generic slab of material being worked;

Figure 10 shows a partial view corresponding to that in Figure 9 which illustrates a different method of coupling the construction to a slab of material being worked;

Figure 11 shows in perspective a further alternative of the construction according to the invention in Figures 3 to 7;

Figure 12 shows a plan view from the bottom of a detail of Figure 11;

Figures 13A to 13C show an accessory for the construction in Figure 11 and its methods of use;

Figure 14 shows a further alternative of the construction in Figures 3 to 7;

Figure 15 shows details of the structure in Figure 14;

Figures 16 and 17 show an accessory for the structure of the machine in Figures 3 to 7.

In Figure 1, an example of known art for executing a circular hole 1 in a slab of stone material 2, or for making a circular outline 3, is shown.

Inside the track defined by circles in broken lines 1 and 3, a series of holes 4 is made in succession by means of a tool such as for example a tubular milling cutter or a cylindrical milling cutter (not shown), which then leaves a coarse surface 5 or 6 which, according to whether it is a hole or disc which is concerned, must then be finished to the exact size of the circles 1 or 3 using well known methods. These methods of working involve a great amount of time and a considerable waste of material as the holes 4, if small, involve low waste but much time and, if large, involve less time but considerable wastage of material.

As shown in Figure 2, according to the present invention, it being necessary to follow the circles 1', 3', an orbital milling 7 is carried out by advancing, for example, in the direction of the arrow F, by means of a cylindrical milling cutter. Once the orbit of the cylindrical milling cutter (not shown) has been completed, the cut is clean and practically finished, in a short time and without significant waste of material from the slab 2.

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Advantageously, in the case of stone material, marble, glass etc., the cylindrical milling cutter is a tool with diamond coating as is well known to an expert in the field.

The apparatus according to the invention will now be illustrated with reference to the remaining figures.

With reference to Figure 3, the apparatus as a whole comprises an annular base 10, on which an annular platform 11 is mounted in a rotatable manner, as will be illustrated more clearly below.

The annular base 10 is equipped with clamps 12, 13 for anchorage by means of wings 14, 15 to at least a pair of suction cups 16, 17 for stable but releasable anchorage of the structure to the slab 18 of stone material or the like being worked.

Mounted on the platform 11 is a pair of vertical guides 19, 20 which support the body 21 of the machine. As can be seen in Figures 5 and 6, a carriage 22 is mounted on the vertical guides 19, 20, which can be moved vertically by means of a screw 23 which can be rotated by means of a handwheel 24.

With reference to Figure 6, the carriage 22 supports a second pair of horizontal guides 25, 26, on which a second carriage 27 slides, which can be moved by means of an adjusting screw 28 which can be rotated by means of a handwheel 29.

The carriage 27 supports an electric motor 30 which, by means of a transmission of known type, sets a tool-holding spindle 31 in rotation.

The platform 21 is furthermore integral with a pair of handles 32, 33, which can be seen in Figures 3 and 4, for the orbital movement of the tool mounted on the spindle 31.

With reference to Figure 6, the operating procedure of the apparatus concerned is as follows: once the base 10 has been fixed to the surface of the slab 18, the platform 11 can rotate about an axis 40 passing through

the centre of the hole to be made in the slab 18, or of the circular outline to be made in the slab 18.

By acting on the handwheel 29, the axis 41 of the tool-holding spindle 31 can be moved for a radius 42 corresponding to the intermediate radius between the radii of the circles 1' and 3' represented in Figure 1. With the handwheel 24, the lowering of the tool mounted on the spindle 31 is adjusted, boring a circular furrow in one or more passes by acting on the handles 32, 33 until the slab 18 is cut through its entire thickness.

At this point, working is ended and the piece being worked can be finished, if necessary, in a conventional manner.

Turning to Figure 4, the suction cups 16, 17 are equipped with small manual pumps 50 in order to create a partial vacuum for retaining the apparatus on the slab 18.

Vacuum gauges 51, 52 make it possible to monitor the partial vacuum in the suction cups 16, 17 and, if necessary, to restore the pneumatic partial vacuum.

In Figure 7, a preferred kinematic arrangement for supporting the platform 11 in a rotatable manner on the base 10 is shown diagrammatically.

The platform 11 is mounted on rollers 53 arranged to roll on rings made correspondingly on the base 10 and on the platform 11.

Rolling elements mounted on pins 55 fixed to the platform 11 roll in a contrasting manner against an undercut 56 made in the base 10 to prevent the platform 11 overturning with what is mounted on it.

Figure 7 shows diagrammatically a diamond-coated milling cutter 57 mounted on the spindle 31 which is shown in partial penetration to the depth P in the material which constitutes the slab 18.

In Figure 8, an alternative of the construction previously described is shown, in which the platform 11 (Figures 3 and 8) is mounted on a base

100 similar to the base 10 in Figure 3 but equipped with a pair of arms 101, 102 articulated at 103, 104 respectively on the base 100.

The outer ends of the arms 101, 102 are coupled, by means of screw elements 105, 106 which can be controlled by means of knobs 107, 108, to releasable anchorage elements 109, 110.

The anchorage elements 109, 110 perform a dual function as they can also operate pneumatically as described previously and shown in Figure 9 also where they are represented in engagement with a slab being worked 111.

In Figure 10, the engagement of the base 100 with a slab 112 being worked which is smaller than the minimum distance which can be engaged with the arrangement shown in Figure 9 is shown.

In the situation in Figure 10, the lower end edges 113, 114 of the slab being worked 112 are engaged by the upper parts 115, 116 of the anchorage elements 109, 110. In this manner, the base 100 is anchored rigidly to the slab being worked 112 during the execution of the required operations.

Figures 11 and 12 show further methods of use of the machine shown in Figure 3.

As can be seen in Figure 11, the platform 10 (Figures 3 and 11) is mounted on a base 120 anchored in a releasable manner on the upper plane of a slab 121 of material being worked.

Figure 12 shows the lower side of the base 120 on which two virtually semi-circular and symmetrical suction-cup structures 122, 123 are provided which are subjected to partial vacuum by a vacuum source by means of the connections 124, 125 in a manner clear to the expert in the field.

It is to be noted that the base 120 is essentially annular and nozzles 127, 128, 129, 130 are arranged along its internal periphery 126 to squirt cooling lubricating water towards the diamond-coated milling cutter 131 to ensure correct operation.

7 As is shown in Figures 13A to 13E, the base 120, before actuation of the pneumatic vacuum source and the mounting of the working machine (not shown in these figures for the sake of clarity), can interact with a centring cup element indicated at 132 which has a cylindrical wall 133 and a base 134 with various concentric circles cut on it, as shown in the figures.

As can be seen in Figure 13C, once the operator has traced marks 135, 136 which indicate the centre 137 of a hole to be made in a slab of material being worked with a diameter D, he positions the base 120 on the slab to coincide approximately with the marks 135, 136, 137, D; he inserts the centring cup element 132 into the annular cavity 132a as shown in Figure 13E and then applies the pneumatic vacuum as described previously. At this point, the base 120 is anchored firmly to the upper surface of the slab being worked.

Turning to Figure 12, it is to be noted that in particular cases it is possible to actuate only one of the suction cup structures 122, 123 when working is to be carried out close to the edges of a slab being worked. To this end, the pneumatic vacuum is to be applied to the only connection 124 or 125 which is engaged with the zone which can be coupled of the slab being worked (not shown).

In Figures 14 and 15, an accessory is shown for the machine described with reference to Figures 3 to 7 which makes it possible to make circular holes which are very much larger than the movement of the spindle 31 in relation to the platform 11.

In this case, a rotatable movable slide 140 is provided, which has an auxiliary base 141 on which the platform 11 can be mounted.

The slide 140 is associated in a rotatable manner with a suction-cup joint 143 of the type described previously and can rotate as indicated by the arrow 144 about the point of pivoting of the suction-cup joint 143.

In the rotation movement, the slide 140 bears on the slab being worked (not shown) by means of rolling supports 145 of known type. The base 141 can be moved on the slide 140 so as to move towards and away from the point of pivoting of the suction-cup joint 143 by sliding on

guides 146, 147, 148, 149. A graduated rule 150 makes it possible to measure and determine the offset of the auxiliary base 141 and therefore to determine the radius of the circle which is to be worked in the slab being worked during the movement as indicated by the arrows 144.

In Figures 16 and 17, an accessory is illustrated for the machine shown in Figures 3 to 7 for use as a copying and/or pantograph milling cutter.

As can be seen in these figures, the accessory provides a base 160 comprising a set of guides and slides 161, 162, 163, 164 with x-y movement so that the auxiliary base 165 can follow any movement in the plane of the slab being worked (not shown) under the control of a knob

166 associated with a copying finger 167.

In this manner, the machine mounted on the platform will follow the layout imposed by a template located in the region of the copying finger

167 (not shown) to cut drawings and/or letters on the slab being worked which are arranged on the template.

A lever 168 controls in a known manner the raising and lowering of the platform 11 mounted on the base 165 to select the zone to be cut as is well known in cutting machines of the copying type (pantographs).

The base 160 can be fixed to the slab of material being worked for example by means of a suction-cup arrangement as described previously.

Alternatives not shown in the figures are possible, for example with a ring gear structure and an auxiliary motor mounted respectively on the base 10 and on the platform 11 (or vice versa) it is possible to bring about automatic orbital advance of the apparatus in order to lighten the manual effort of the operator.

Furthermore, with an automatic control known per se on the movement controlled by the handwheel 29, which co-ordinated with the rotation of the platform 11, it would be possible to implement a copying structure so as to make non-circular cuts in the slab 18 being worked such as for example rectangles, squares, polygons and the like.

The present invention has been described with reference to its currently preferred embodiments and it will be understood that it will be possible for an expert in the field to make alternatives and modifications without departing from the scope of the present industrial patent.