WO2003082711A1

WO2003082711A1 - Bearing surface of a belt conveyor with anti-friction and anti-wear sliding surface

Info

Publication number: WO2003082711A1
Application number: PCT/IT2003/000177
Authority: WO
Inventors: Luigi Pedrini
Original assignee: Luigi Pedrini
Priority date: 2002-03-29
Filing date: 2003-03-25
Publication date: 2003-10-09
Also published as: EP1494940A1; ITMO20020077A1; ITMO20020077A0

Abstract

The sliding plane of a conveyor belt (9, 17) with an anti-friction and anti-wear sliding surface (1, 14) comprises a metal support structure (8, 21) for the plane and thus for the conveyor belt, and has at least one portion of the sliding surface of the conveyor belt, consisting of plates (3, 5) made from hard material, embedded in support and attachment means (2, 4, 38, 41, 44) like a single plate (43) or in groups of plates (2, 4) so as to compensate for the differences in thickness (29) and/or shape (35, 37) and/or planarity (32) of the plates; said support means is fixed (7, 25, 40, 46) also in removable manner, on said metal structure to constitute said sliding plane. Moreover, said plane has said support means for the single plates or for the groups of plates locked with screws, glued or applied with joints adapted to and even able to slide in the metal support structure (1, 8, 21) for the plane or with removable portions (1, 17) of the sliding plane, in turn able to be fixed to said structure.

Description

BEARING SURFACE OF A BELT CONVEYOR WITH ANTI-FRICTION AND ANTI- WEAR SLIDING SURFACE

DESCRIPTION The invention concerns a bearing surface of a belt conveyor with anti-friction and anti-wear sliding surface, that is a plane for a belt, which, due to the configuration of the support structure of the belt itself, helps to obtain substantial durability of the.sliding surface in particular in the treatment of hard stone materials where the concentration of pressure of the tool leads to abrasion and wear of said surface.

The state of the art specifies that the treatment of the aforementioned stone materials, and in particular of porcelain stone- ware, comprises reinforced rubber fabric belts arranged to slide on planar surfaces of the structure of the machine tool in which it is used. The action of the tools due to the surface involved, the material in treatment and the type of abrasive material used, is a compression of the tool on the material in treatment which in turn rests upon the underlying belt sliding upon said planar surfaces. The constancy of the-working motion of the tool, of the forward motion of the belt and of the relative reciprocal position between tool, material and band, i.e. the underlying planar sliding surface, leads to the concentration of wear in certain posi- tions along the planar surface, from which derive various operating problems .

A first problem, given the substantial variability of the size of the material in treatment, comes with the consumption of the planar surface, mainly in the mid-point of the field of treatment of the tool, since the material is always initially centred at said mid-point, as in the case of smoothing and/or polishing. From this the passage to a greater transversal size of the material in treatment makes it act as a bridge over the sag of said planar surface: from this there is more possibility of breaking of the material by flexing, under the strong thrust of the abrasive tool used, with the consequent shut-down of the machine and relative production losses. In the case of calibrating with a cylindrical roller, the wear is concentrated under the position of the roller, by the constant action of said roller generally arranged transver- sally to the motion of the band and of the materials in treatment: in this case breakage by flexing can also take place with materials of the same size.

A second problem comes from the unavoidable slight elasticity of the conveyor belt itself: the high friction between the lower surface of the belt and said planar sliding surface does not allow the belt to slide on it with uniform motion, necessary for the perfect successful treatment of the material. Indeed, there is the characteristic advancing in steps of the belt and of the material supported by it, with the consequent vibration or marbling of the surface in treatment. Also in this case, the material is discarded or requires further correction treatments. In any case, the overall costs increase significantly.

Finally, in the state of the art various forms of support planes for the belt are adopted which can be shaped and replaced in various ways. Indeed, with the worsening of the aforementioned problems the drastic solution of replacement of said planar surfaces is the most advantageous, even though it requires many days shut-down of the machine and this may be necessary many times each year. The planes known in the state of the art, mainly made from steel, tempered in various ways, do not allow a drastic reduction in the aforementioned problems which become particularly pronounced with the increase in working speed of the machine, directly linked to the advancing speed of the conveyor belt.

Such a state of the art is susceptible to substantial improvements with regard to the possibility of substantially reducing the problems encountered and obtaining a higher advancing speed of the conveyor belt, as well as a greater period between each maintenance operation of the aforementioned planar sliding surfaces of the belt. From the above derives the need to solve the technical problem of realising a configuration of the planar sliding surface of the conveyor belt which can have less friction than that which is currently known and which can easily be realised on new machines and which can be applied to existing machine tools.

The invention solves the aforementioned technical problem by adopting: a sliding plane of a conveyor belt with an anti-friction and anti-wear sliding surface, comprising a metal support struc- ture for the plane and thus for the conveyor belt, characterised in that said plane has at least one portion of the sliding surface of the conveyor belt, consisting of plates made from hard material, embedded in support and attachment means, as a single plate or in groups of plates, so as to compensate for the differences in thickness and/or shape and/or planarity of the plates. Said support means is fixed, also in a removable manner, on said metal structure to constitute said sliding plane.

By adopting, in a preferred embodiment, said support means for the single plates or the groups of plates locked with screws to the metal support structure for the plane or with removable portions of the sliding plane, in tur-n able to be fixed to said structure.

By adopting, moreover, in a further embodiment: said support means for the single plates or groups of plates applied with gluing to the metal support structure for the plane or with removable portions of the sliding plane, in turn able to be fixed to said structure.

By adopting, furthermore, in a further embodiment: said support means for the single plates or groups of plates fixed with joints adapted to and even able to slide in the metal support structure for the plane or with removable portions of the sliding plane, in turn able to be fixed to said structure.

By adopting, moreover, in a further embodiment: said group of plates made from hard material all grouped together on a single strip. By adopting, furthermore, in a further embodiment: the plates of said group with similar plan surfaces.

By adopting, moreover, in a further embodiment: the plates of said strip with advantageously rectangular plan shape. By adopting, furthermore, in a further preferred embodiment: the plates embedded in the single support means or in the group equipped with at least one side portion, with respect to the face in contact with said conveyor belt, undercut for the secure gripping of the plate to the material of said support means . By adopting, finally, in a further embodiment: contiguous strips, in the direction of motion of the conveyor belt, with staggered arrangement between the respective plates made from hard material of the strips.

The advantages obtained by this invention are: the support and sliding surface for the belt is harder wearing to the abrasion made by the belt on it, from this it follows that the problems of surface sag known in the prior art are overcome, thus maintaining planarity with a substantial reduction in the percentage of waste due to breakage by flexing and to the irregular surface for the advancing in steps of the belt. The arrangement of the plates with different width transversal to the motion of the belt allows the non-alignment of the joints, in the direction of motion of the belt, between the successive strips of plates, so as to avoid the formation of longitudinal heels on the inner surface of the belt. Moreover, the anti-wear material used, aluminium-based ceramic, has good resistance to the chemical attack of the products used in the treatment and which are transported by the water widely used to cool the tools. The construction and replacement of the strips of plates resistant to wear does not require the calibrating treatment of the strips themselves or of the portion of sliding surface of the conveyor belt, but the differences in thickness, parallelism and crowning between the two faces of the plates are compensated for at the time of production of the strip or support for the single plate. Finally, the replacement of the strips or single plates takes place quite easily by withdrawal of the strips or locking with known screws: as stated above, it is no longer necessary to carry out a post-assembly rectification, since said strips of plates or the single embedded plate is already at mould- ing at the required thickness, constant within extremely strict allowance limits .

A way to carry out the invention is illustrated, just as an example, in the five attached tables of drawings in which Figure 1 is the perspective view of a portion of planar sliding surface of the conveyor belt, according to the invention, equipped with strips of interchangeable plates. Figure 2 is the schematic plan view of a conveyor belt equipped with the aforementioned planar sliding surface, arranged on a machine tool for smoothing materi- als in sheets/plates. Figure 3 is a schematic view in section III- III of figure 2, for a smoother with a head with oscillating sectors . Figure 4 is a limited schematic section of a side bevelling/calibrating machine for plates, where on the left it is shown with a side-calibrating tool and on the right with a bevelling tool. Figure 5 is a plan view of a single strip of plates. Figure 6 is the section VI-VI of figure 5 of said strip. Figure 7 is the section VII-VII of figure 5 of said strip. Figure 8 is the section of a portion of said planar sliding surface with said strips of plates arranged in their seat which has already been occupied, where the softest material has more wear. Figure 9 is the plan view of a strip of plates with screw attachment to the support plane. Figure 10 is the plan view of single plates equipped with individual screw attachment for each plate. Figure 11 is the section XI-XI of figure 9.

In figure 1 the portions of sliding surface of the conveyor belt in which the strips 2 of plates 3 made from material with high resistance to abrasion are inserted are indicated with 1. The strips 4, equipped with plates 5 of a size slightly different to the previous ones 3, when combined allow the composition of said strip 4 with a different number of plates, also different in size.

Figure 2 shows the attachment holes 7 of the portion 1 of sliding surface at the underlying metal support structure 8 for the conveyor belt 9: the plates 2 coating the planar sliding surface of the belt 9 are applied to the face 10 of said portions 11 facing towards the belt. The same figure shows the outlines 11 of the central working area of each operating head 12, Figure 3, in a smoothing machine for the stone material 13 being treated.

Figure 4 shows a portion of metal sliding surface, with coating plates 15 and 16, of a belt 17 for a side bevelling/calibrating machine for a ceramic plate 18 being treated. The plate is treated through the cup wheel 19 being side calibrated, and being bevelled through an analogous cup wheel 20. It also shows: the metal support structure 21 for said metal portions of sliding surface 14 to constitute the planar sliding surface of the belt 17; the return branch 22 of said belt; the pressure rollers 23 and 24 of the plate being treated which, through the friction generated in the contact with the surface of the belt 17, allows the exact positioning thereof with respect to said side-calibrating and bevelling tools 19, 20.

Figure 5 shows the side edges 25 of the strip 2 or 4 inclined to form a dovetail guide with the seat in the relative portion of metal sliding surface 1 or 14. Said strip has flat ends 26. Figure 6 then shows the inclined edges 27 to allow a stable clamping of the plate 3 in the material constituting said strip 2 or 4. The plate 28 made from material resistant to wear has a thickness 29 different from the plate 3 which is compensated by the different thickness of the material constituting the strip. It also shows: holes 30 for the exact positioning of the plates in the mould of said strips 2 or 4. Figure 7 shows a plate 31 with the face 32 embedded not parallel to the face 33 intended to support the convey- or belt. Whilst figure 8 shows a plate 34 with the embedded face 35 concave, i.e. not planar to the face 33, as well as the plate

36 with the embedded face 37 convex.

Finally, Figure 9 shows a strip 38 of plates 3 equipped with lowered end lug bolts 39, for attachment with screws to the metal structure 8 of the machine or to the portion of sliding surface 1 or 14, through the hole 40. The attachment can advantageously take place like in the strip 41, analogous to the previous one 38, but with smaller lowered lug bolts 42, to allow greater support of the overlying conveyor belt.

Figure 10 shows a single plate 43, made from material resistant to abrasion, embedded in a support 44 made from material analogous to that of the aforementioned strips 2, 4, 38 or 41, also equipped with lowered lug bolts 45 for attachment with screws in the holes 46 to the metal structure 8 of the machine or to the portion of sliding surface 1 or 14.

The production of the strips 2, 4, 38 and 41 and of the sup- ports 44 for plates made from anti-wear material takes place by positioning of the plates in the mould, taking care to position the better face 33 at the side intended to support the sliding of the conveyor belt 9, 17, and keeping them in position with the presser through the hole 30 during moulding. The material making up the strip 2, 4, 38 or 41, as well as the support 44 for the embedded plate 43, can be injection moulded plastic, also reinforced, as well as injection mouldable metal like aluminium, Zama alloy, white metal, bronze, etc., or else rubber, Bakelite and other similar materials, or even metal which can be sintered. The assembly of the strips of coating plates made from anti- wear material according to the invention takes place by gluing, screw attachment or even by insertion, in the case of a dovetail guide 25, of them on the portions 1, 14 of sliding surface of the belt 9, 17 for the prearranged purpose. Or else the supports 44 for single plates 43 can be individually fixed through screws to the structure of the machine tool or to the support for the conveyor belt.

The easy replacement realised in the plates housed in the strip 2, 4, 38 or 41, or in the single support 44 with attachment lug bolts 45 allows their replacement on the machine tool, where this type of conveyor belt is generally arranged for high loads normal to it, in a fast manner and specific for all or part of the sliding surface of the conveyor belt. The specific replacement of just some strips in the single portion of sliding surface 1, 14 or of some plates embedded in their support 44 with attachment lug bolts, allows specific maintenance in the zones of maximum wear, and consequently maintenance which is quite fast and certainly more cost-effective than the previous maintenance with total replacement of the sliding surface of said conveyor belt.

In operation, finally, the conveyor belts equipped with coating of the sliding surface according to the invention have greater dimensional stability and thus less deformation in the planarity so as to make them particularly useful in typical uses with high con- centrations of forces of machines for treating stone materials and porcelain stoneware.

The plates of anti-wear material advantageously consist of ceramic with high content of materials resistant to wear like aluminium. A suitable material is ceramic with at least 90% alumin- ium, or else widia, stellite and similar material content.

Finally, the sliding surface described can also advantageously be used for conveyor belts not directly used in association with specific machine tools, but will certainly be advantageous where in the operation of the conveyor belt there is localised wear of the aforementioned sliding surface. Moreover, it may also be advantageous to use the plates resistant to wear also for conveyor belts with distributed wear, but still needing fast and cost-effective maintenance.

in the practical embodiment the materials, the sizes and the 22 PP.200!^' details of execution can be different from those indicated, but technically equivalent to them, without for this reason departing from the legal scope of the present invention.

Claims

1. Sliding plane of a conveyor belt (9, 17) with an anti-friction and anti-wear sliding surface (1, 14), comprising a metal support structure (8, 21) for the plane and thus for the conveyor belt, characterised in that said plane has at least one portion of the sliding surface of the conveyor belt, consisting of plates (3, 5 ) made from hard material, embedded in support and attachment means (2, 4, 38, 41, 44), like a single plate (43) or in groups of plates (2, 4), so as to compensate for the differences in thickness (29) and/or shape (35, 37) and/or planarity (32) of the plates; said support means are fixed (7, 25, 40, 46), also in a removable manner, on said metal structure to constitute said sliding plane.

2. Sliding plane of a conveyor belt (9, 17), according to the previous claim, characterised in that it has said support means for the single plates or for the groups of plates locked with screws (7, 40, 46) to the metal support structure (1, 8, 21) for the plane or with removable portions (1, 17) of the sliding plane, in turn able to be fixed to said structure.

3. Sliding plane of a conveyor belt (9, 17), according to the previous claim 1, characterised in that it has said support means for the single plates or groups of plates applied with gluing to the metal support structure (1, 8, 21) for the plane or with removable portions (1, 17) of the sliding plane, in turn able to be fixed to said structure.

4. Sliding plane of a conveyor belt (9, 17), according to the previous claim 1, characterised in that it has said support means for the single plates or groups of plates fixed with joints (25) adapted to and even able to slide in the metal support structure (1, 8, 21) for the plane or with removable portions (1, 17) of the sliding plane, in turn able to be fixed to said structure.

5. Sliding plane of a conveyor belt (9, 17), according to one of the previous claims 1-4, characterised in that it has said group of plates (3, 5) in hard material grouped together on a single strip ( 2 , 4 ) .

6. Sliding plane of a conveyor belt (9, 17), according to the previous claim 5, characterised in that it has the plates (3, 5) of said group with similar plan surfaces.

7. Sliding plane of a conveyor belt (9, 17), according to the previous claim 5, 6, characterised in that it has the plates (3, 5) of said strip with advantageously rectangular plan shape.

8. Sliding plane of a conveyor belt (9, 17), according to one of the previous claims 1-6, characterised in that it has the plates embedded in the single support means (44) or in the group (2, 4) equipped with at least one side portion (27), with respect to the face in contact (33) with said conveyor belt, undercut for the secure gripping of the plate to the material of said support means .

9. Sliding plane of a conveyor belt (9, 17), according to one of the previous claims 5, 6 or 7, characterised in that it has contiguous strips ( 4 ) , in the direction of motion of the conveyor belt, with staggered arrangement between the respective plates (5) made from hard material of the strips.

10. Sliding plane of a conveyor belt (9, 17), according to one of the previous claims 1-9, characterised in that the hard materi- al constituting the plate advantageously contains at least 90% aluminium.

11. Sliding plane of a conveyor belt (9, 17), according to one of the previous claims 1-9, characterised in that the hard materi- al constituting the plate is advantageously stellite.

12. Sliding plane of a conveyor belt (9, 17), according to one of the previous claims 1-9, characterised in that the hard material constituting the plate is advantageously widia.

13. Sliding plane of a conveyor belt (9, 17), according to one of the previous claims 1-9, characterised in that the hard material constituting the plate is advantageously moulded plastic material.

14. Sliding plane of a conveyor belt (9, 17), according to one of the previous claims 1-9, characterised in that the hard material constituting the plate is advantageously injection-moulded metal or metal alloy.

15. Sliding plane of a conveyor belt (9, 17), according to one of the previous claims 1-9, characterised in that the hard material constituting the plate is advantageously sintered metal material.

16. Sliding plane of a conveyor belt (9, 17), according to one of the previous claims 1-9, characterised in that the hard material constituting the plate is advantageously rubber or moulded Bakelite.