Machine for cutting slabs of various materials such as marble, ceramics, terracotta, sandstone, glass and the like into tesserae

Abstract: A machine for cutting various materials, such as marble, ceramics, terracotta, sandstone, glass and the like, into tesserae, comprising: guiding elements which are composed of sliding rails (5,8) arranged like the sides of a square; a plurality of carriages (9-12), each whereof has elements (31) for supporting a slab (B) and can slide on the rails; elements (13,21,23) for moving the plurality of carriages (9-12) along the rails (5,8) so that the slabs on the support elements (31) maintain the same orientation along the entire path formed by the rails; and two slab cutting elements (43,44) arranged along two mutually perpendicular sides of the square, each element being constituted by a pack of blades (45,46) which rotate about an axis perpendicular to the respective side.

Description: The present invention relates to a machine for cutting various materials, such as marble, ceramics, terracotta, sandstone, glass and the like, into tesserae. The term "slab" alone will be used in the continuation of the description for the sake of convenience; this term denotes herein a slab of any one of the above materials. Currently commercially available machines for cutting slabs into tesserae include a support for the slab, which is made to advance under a pack of rotating circular blades. The slab is thus cut into a plurality of adjacent strips. Then the support is rotated through 90° and placed under the rotating blades again, so that the strips are cut into quadrangular tesserae. Conventional machines have an unsatisfactory efficiency due to the need to transfer the strips, after the first cut, from the output to the input of the machine to perform the second cut at right angles to the first one. A large number of rejects or imperfect tesserae has been observed with these conventional machines, especially if the slabs are made of soft and crumbly material. In order to obviate these drawbacks, this same Applicant has developed a machine which is disclosed in Italian patent 1274815. The particularity of the machine consists in that the support of the slab can rotate and performs a forward stroke and a return stroke. The forward stroke cuts the slab into strips which are parallel to the advancement direction of the support, while the return stroke, performed after the support has turned through 90°, cuts the strips into quadrangular tesserae. The aim of the present invention is to provide a machine which allows to achieve a higher performance than conventional machines from both a quantitative and a qualitative point of view. Within the scope of this aim, an object of the present invention is to provide a machine which can work on any kind of material and can cut tesserae of any size without causing chipping or breakage of the tesserae. Another object of the present invention is to provide a machine which is constructively simple and inexpensive and is capable of coping with the intense mechanical stresses to which it is subjected during work. This aim, this object and others which will become apparent hereinafter are achieved by the machine defined in claim 1. Further characteristics and advantages of the machine according to the present invention will become apparent from the following detailed description of an embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is an elevation view of a machine embodying the present invention; Figure 2 is a sectional plan view, taken along the plane II-II of Figure 1; Figure 3 is a perspective view of a carriage for supporting a slab to be cut; Figure 4 is a partially sectional plan view of the carriage of Figure 3; Figure 5 is a sectional view, taken along the plane V-V of Figure 4; and Figure 6 is a schematic side view of the carriage. With reference to the above figures, the machine comprises a framework which is composed of vertical posts 1 connected, in an upward region and in a downward region, by frames 2 and 3 respectively. The posts 1, above the lower frame 2, are mutually connected by cross-members 4 which form the sides of a square on which profiled elements 5 are fixed. The profiled elements have a C-shaped cross-section which is open towards the inside of the square delimited by said profiled elements. The cross-members 4 rigidly support a structure, generally designated by the reference numeral 6, which lies inside the square formed by the profiled elements 5. The structure 6 supports a square secondary frame 7, to the sides of which profiled-elements 8 are fixed externally; the profiled elements 8 have a C-shaped cross-section which is open towards the outside, i.e., towards the profiled elements 5. The sides of the squares formed by the profiled elements 5 and 8 are mutually parallel and co-planar, so that the latter form the rails for the sliding of a set of four carriages 9, 10, 11, and 12. The carriages 9, 10, 11 and 12 are pushed along the rails 5 and 8 by a movement unit, generally designated by the reference numeral 13, which is composed of a drum 14 which is rotatably supported about a vertical axis A on the frame 2. A ring gear 15 is rotationally rigidly coupled to the drum 14 and a pinion 16 meshes therewith. The pinion 16 is keyed on a vertical shaft 17, which is supported in the frame 2 and on which a sprocket 18 is also keyed; a chain 19 meshes with said sprocket and is driven by a gearmotor 20 mounted on the framework. Four openings are formed in the drum 14 at the top; the cylinders 21 of a corresponding number of hydraulic jacks are inserted through the openings, the jacks protruding from the inside towards the outside of the drum 14. Each cylinder 21 is supported in brackets 22 which are welded on the outside of the drum 14 and has a stem 23 which protrudes to the side of a respective arm 24 which cantilevers out from the top of the drum 14. The arms 24 form a sort of cross, and sliding guides 25 are fixed thereon for respective sliding blocks 26 which are articulately coupled to the ends of the stems 23 of the jacks. The carriages 9-12 are supported on the sliding blocks 26 so that they can rotate about vertical axes. As shown more clearly by Figures 3, 4 and 5, each carriage 9-12 comprises a square base 27 from which a pivot 28 protrudes downward for articulation in the respective sliding block 26. Sets of rollers 29 are fitted on the sides of the base 27 so that they cantilever out; their dimensions are such that they slidingly engage the profiled elements 5 and 8. Four columns 30 are fixed above the base 27, at the corners, and support a platform 31 for supporting the slabs to be cut. The platform 31 comprises a seat for accommodating a slab B, which is formed by a slab supporting surface 32, by two parallel longitudinal walls 33 and by a transverse wall 34 which joins, at one end, the longitudinal walls 33. The walls 33 and 34 and the supporting surface 32 are affected by transverse slots 35 and longitudinal slots 36 which are mutually perpendicular and are meant to allow the passage of the cutting blades, as will become apparent hereinafter. Guiding bushes 37 for a pair of parallel rods 38 are rigidly coupled to the base 27, below the platform 33. The rods are perpendicular to the wall 34 and are connected, on the side lying furthest from the wall 34, by a cross-member 39. The cross-member 39 can be actuated along the bushes 37 by means of a hydraulic jack, whose cylinder 40 is fixed to the base 27 below the platform 31 and whose stem 41 is rigidly coupled to the cross-member 39. A plurality of fingers 42 protrude from the upper edge of the cross-member 39, are bent at right angles parallel to the rods 38 and are separated by gaps which are aligned with the longitudinal slots 36 to allow the passage of the cutting elements. The fingers 42 form a pusher which is meant to lock a slab B accommodated in the seat formed by the walls 33 and 34 against the opposite transverse wall 34. In order to cut the slabs B two cutting units 43 and 44 are provided which are arranged above the movement plane of the carriages 9-12. Each unit comprises a cutting element which is composed of a pack of circular blades 45, 46 keyed on a horizontal shaft 47, 48 which protrudes radially from the rotation axis A of the drum 14. The shaft 47 of the pack of blades of the cutting unit 43 is aligned along an axis C which is perpendicular to one side of the rails 5, 8 and intersects the axis A, while the shaft 48 of the pack of blades of the second cutting unit 44 is aligned along an axis D which is rotated through 90° with respect to the preceding axis C. In practice, therefore, the two shafts 47, 48 of the two units 43, 44, like the respective packs of blades 45 and 46, are mutually perpendicular. The shafts 47 and 48 are supported in respective supports 49 and 50 which are fixed to the frames 5 and 7 and at a level at which the circular blades 45, 46 are substantially tangent, with their lower edge, to the supporting surface 32 for the slab B. Respective pulleys 51, 52 are keyed on the inner ends of the shafts 47 and 48, and transmission belts 53, 54 are wound on said pulleys; said belts receive their motion from electric motors 55, 56 which are mounted on brackets rigidly coupled to the framework 1. The packs of blades 45, 46 are kept at the operating temperature by a cooling liquid supplied through suitably directed nozzles. In order to prevent the liquid from being scattered into the surrounding environment, each pack of rotating blades is protected by an overlying hood 57, 58. Operation of the machine is described hereinafter by following the movements of a slab B until it is fully divided into tesserae. First of all, the slab B to be cut into tesserae is placed in the seat of the carriage that is in the position E, which faces the cutting unit 43 and is designated by the reference numeral 10 in Figure 2. Through the rotation of the drum 14, the carriage 10, pushed by the arm 24, moves in the direction F until it reaches the corner G formed by the rails 5 and 8. During this movement, the respective jack 21, 23 extends in order to follow the sliding of the sliding block 26 imposed by the engagement of the rails 5, 8. When the carriage 10 has reached the corner G, the jack 21, 23 is activated and, by producing the return movement of the sliding block 26, in combination with the rotation applied by the drum 14, forces the carriage 10 to move in the direction H until it reaches the position I (the position of the carriage 11 in Figure 2), beyond which the jack 21, 23 extends further until the corner L is reached. Once the corner L has been passed, the jack 21, 23 is activated so as to retract, in order to allow the carriage to move in the direction M. During said movement, the slab B passes through the pack of rotating blades 45, which cut the slab into strips as wide as the gap between the blades. The strips, however, remain locked between the fingers 42 and the opposite wall 34. Then the carriage, after deactivating the jack 21, 23, reaches the corner N and then continues in the direction O. In this segment too, the jack 21, 23 is activated until the carriage reaches the position in which alignment with the axis D occurs; said jack is deactivated until the corner Q is reached. During this segment, the strips, by passing under the pack of blades 46, are cut transversely so as to form square tesserae which continue to rest on the surface 32. However, the tesserae, due to the thickness of the cutting blades, remain loose and can be removed during the subsequent travel from the corner Q to the position E, for example by means of suction elements so as to allow the placement of a new slab. The above situation described in relation to one carriage is also repeated in succession for all the other carriages, so that at each turn of the drum 14 four slabs supported by the carriages 9-12 are cut. Loading of a new slab B can of course occur at any point along the path from the corner Q to the corner L. It is noted that the outer rails 5, at the corners G, L, N and Q, have cutouts 59 to allow the rollers 29 arranged on the outer sides of the carriages to leave one rail 5 and respectively engage the adjacent rail 5. For the same reason, the inner rails 8 are open longitudinally at the corners in order to allow the rollers 29 arranged on the inner sides of the carriages to leave the rails 8. However, in order to allow to support the carriage also when the internal rollers have disengaged from the respective rails, L-shaped extension surfaces 60 cantilever out from the rails; the last of the rollers that leave the respective inner rail and the first of the rollers that must engage the subsequent inner rail continue to rest on the extension surfaces 60 temporarily. It is evident that the described invention perfectly achieves the intended aim and objects. In particular, it is noted that during cutting the slab and the strips remain locked at all times, ensuring the formation of tesserae which are free from chipping and a minimal percentage of rejects. Figure 6 illustrates a different embodiment in which the platform 31 is mounted rotatably on the base 27 so as to rotate about the axis 61. To the side of the platform 31 there is provided a free roller 62 which, by engaging the profile of a stationary cam 63, actuates the tilting of the platform and therefore the unloading of the tesserae into an underlying collection region. The cam 63 is arranged along a segment which lies between the corners Q and G or G and L, upstream of the region where a new slab B is loaded onto the carriage from which the tesserae have been removed beforehand. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: A machine for cutting various materials, such as marble, ceramics, terracotta, sandstone, glass and the like, into tesserae, characterized in that it comprises: guiding means which are composed of sliding rails (5, 8) comprising an outer square rail (5) and an inner square rail (8) which form a square configuration having mutually parallel sides; a plurality of carriages (9-12), each whereof has means (31) for supporting a slab (B) and can slide on said rails; means (13, 21, 23) for moving said plurality of carriages (9-12) along said rails (5, 8) so that the slabs on said supporting means (31) maintain the same orientation along the entire path formed by said rails; and two slab cutting elements (43, 44) arranged along two mutually perpendicular sides of said square, each cutting element being constituted by a pack of blades (45, 46) which rotate about an axis perpendicular to the respective side. The machine according to claim 1, characterized in that said sliding rails are formed by profiled elements having mutually facing C-shaped cross-sections. The machine according to claim 2, characterized in that said means for moving said carriages comprise: a drum (14), which is rotatably supported about a vertical axis and is actuated with a continuous motion; a set of four arms (24), which are mutually perpendicular and are radially rigidly coupled to said drum (14), each arm slidingly supporting a respective sliding block (26), a set of four hydraulic jacks (21, 23) which are mounted on said drum (14) and in which each one of the jacks (23) is connected to a respective sliding block (26), said carriages (9-12) being supported on said sliding blocks so that they can rotate about vertical axes. The machine according to claim 3, characterized in that each one of said carriages comprises a square base (27), from which a pivot (28) protrudes downward for articulation in the respective sliding block (26), respective sets of rollers (29) being mounted so as to cantilever out from the sides of said base and having dimensions which allow them to slidingly engage the profiled elements that form said rails (5, 8). The machine according to claim 4, characterized in that columns (30) are fixed above said base (27) in order to support a platform (31) for supporting the slabs (B) to be cut, said platform comprising a seat for accommodating a slab, which is formed by a slab supporting surface (32), by two parallel longitudinal walls (33) and by a transverse wall (34) which joins said longitudinal walls at one end, said longitudinal walls (33) and said supporting surface (32) being affected by transverse slots (35) and longitudinal slots (36) which are mutually perpendicular and are meant to allow the passage of the blades (45, 46) of the cutting elements (43, 44), supports (37) being arranged between said base (27) and said platform (31) in order to guide a pair of sliding rods (38) which are parallel to said longitudinal walls (33) and are connected, on the opposite side with respect to said transverse wall (34), by a cross-member (39) which can be actuated along said rods (38) by means of a hydraulic jack (40, 41) which is mounted on said base (27), an element (42) for locking said slab against said transverse wall (34) being rigidly coupled to said cross-member (39). The machine according to claim 5, characterized in that said platform (31) is rotatably mounted on said base and has a roller (62) suitable to engage a stationary cam (63) which is arranged along a segment of the path followed by the carriages (9-12) upstream of the region for loading the slabs to be cut, said cam (63) being suitable to actuate the tilting of the platform (31) and the unloading of the tesserae into a collection region. The machine according to claim 5, characterized in that said element for locking said slabs is constituted by a plurality of fingers (42) which protrude from the upper edge of said cross-member (39) and are bent at right angles parallel to said longitudinal walls (33), said fingers (42) forming, between them, gaps which are aligned with said longitudinal slots (36) to allow the passage of the blades (45, 46) of the cutting elements (43, 44). The machine according to claim 7, characterized in that said rotating pack of circular blades (45, 46) is arranged along the advancement path of said carriages (9-12), said blades being keyed on a respective horizontal shaft (47, 48) which protrudes radially from the rotation axis (A) of said drum (14), a shaft (47) of the pack of blades (45) of a cutting unit (43) being aligned along an axis (C) which is perpendicular to one side of the rails and passes through the rotation axis (A) of said drum (14), and the shaft (58) of the pack of blades (46) of the second cutting unit (44) being aligned along an axis (D) which is rotated by 90° with respect to the preceding axis (C), said shafts (47, 48) being supported at a level at which the circular blades (45, 46) are substantially tangent, with their lower edge, to the supporting surface (32) for the slab (B).

Inventors: PLACUZZI MAURIZIO, PLACUZZI, MAURIZIO
Applicants: SICIS INT SRL, SICIS S.R.L.
Application year: 1998
Main classification: B28D1
IPC codes: B28D1