Machine for machining edges, particularly of glass plates

Abstract: The machine for machining edges, particularly of glass plates, includes, on a supporting structure (1), mutually opposite conveyors (2) which extend continuously and are suitable for moving the plates to be machined at machining heads. At least one of the conveyors has a plurality of adjacent sliding blocks (10) each of which includes an elongated supporting body (11) on which a covering (20) is provided which has blocks (23) for gripping the plates being machined. The elongated supporting body (11) has, inside it, a T-shaped seat (25) for slidingly retaining and guiding a rod-like element (26) to which a pad (27) is connected; the pad (27) can be arranged at a presettable distance from the blocks (23), which have a fixed vertical placement with respect to the machining surface.

Description: The present invention relates to a machine for machining edges, particularly of glass plates. As is known, machines for machining the edges of glass plates, such as for example chamfering machines, generally have, on a supporting structure, a pair of opposite conveyors which extend continuously and retain the plate, arranged edgeways, between them; said plate must be moved to be machined on machining heads which generally have grinders which protrude upward from the machining table. In order to allow the accommodation of the machining heads, the sliding blocks which retain the glass plates and are provided on the continuously extending conveyors must therefore remain at a certain distance from the machining surface, since they would otherwise interfere with the machining heads. It is also known that in some cases it is necessary to machine the edges of small glass plates. Accordingly, in order to try to solve this problem, solutions have already been provided which in practice entail a sliding block which can move with respect to the conveyor along a direction which is substantially perpendicular to said conveyor advancement direction, so that it is possible to retain even small plates. However, this solution creates considerable disadvantages, since the guides for the translatory motion of the sliding blocks, which are moved monolithically, are unavoidably subjected to very heavy wear, being exposed to the machining dust and waste, which is generally composed of the abrasive compound which constitutes the grinder and of minute glass particles. In these conditions, the machine is thus subjected to very heavy wear, which is increased by the fact that the sliding blocks are moved continuously, since with the structure according to the known art the sliding block is necessarily arranged in its lowered position along the portion during which it retains the plate but is lifted in the opposite portions, so that the movement is continuous and wear is very heavy. Furthermore, cam systems are used in order to perform the translatory motion of the sliding block; such systems do not allow to move the conveyors in the opposite direction, as is instead required for maintenance or for special events, since the rollers which must follow the cams would remain in raised position during the reversal step and would consequently interfere with the cams, creating unavoidable breakages. Also known from DE-A-3,821,287 is a machine for machining edges as defined in the precharacterizing part of claim 1. SUMMARY OF THE INVENTION The aim of the invention is indeed to eliminate the above described disadvantages by providing a machine for machining edges, particularly of glass plates, wherein the sliding block is always kept at a constant height with respect to the machining surface and only a small and very thin grip part, which can slide with respect to the guides which are sealingly protected with respect to the outside, is moved. Within the scope of the above aim, a particular object of the invention is also to allow even very sharp chamfering angles with no interference of the machining heads, since the part which retains the plates is small and has an extremely reduced thickness, so that interference is always avoided. Another object of the present invention is to provide a machine for machining the edges of glass plates wherein it is possible to guide the translatory motion of the part which is arranged so as to extend the sliding block even during the steps of the reversal of the motion of the conveyor, without having problems of damage or interference. Not least object of the present invention is to provide a machine for machining edges, particularly of glass plates, which by virtue of its peculiar characteristics of execution is capable of giving the greatest assurances of reliability and safety in use. This aim, these objects, and other aims and objects which will become apparent hereinafter, are achieved by a machine for machining edges, particularly of glass plates, as defined in the appended claims 1-10. BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages will become apparent from the description of a preferred but not exclusive embodiment of a machine for machining edges, particularly of glass plates, according to the present invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein: figure 1 is an exploded schematic perspective view of a sliding block according to the invention; figure 2 is a sectional view of the connection between the supporting body and the rod-like element; figures 3 and 4 are longitudinal sectional views of the sliding block, with the pad respectively in the fully lowered position and in the fully raised position; figure 5 is a sectional view of the sliding block, taken along a median plane, illustrating the arrangement of the covering with respect to the supporting body; figure 6 is a sectional view, taken along the line VI-VI of figure 3; figure 7 is a schematic plan view of the machine according to the invention, illustrating one of the conveyors; figures 8 and 9 are views of the means for actuating the translatory motion of the rod-like element in two different operating positions; figure 10 is a schematic view of the means for positioning the translatory means of the rod-like element. With reference to the above figures, the machine for machining edges, particularly of glass plates, comprises a supporting structure, generally indicated by the reference numeral 1 in figure 7, on which two conveyors 2 are provided; said conveyors are arranged mutually opposite so as to retain, between them, a glass plate arranged edgeways. The conveyors extend continuously, and each has an arm 2a which is arranged adjacent so as to engage the plates. At least one of the conveyors is constituted by a plurality of sliding blocks, generally indicated by the reference numeral 10, each of which comprises a supporting body 11 which is provided, in a rearward position, with couplings, generally indicated by 12, for the connection of the various adjacent sliding blocks so as to define in practice a chain which extends continuously. A covering, indicated by 20, is provided on the supporting body 11, is advantageously made of rubber or similar materials and is connected by means of lugs 21 which are inserted in holes 22 defined on the supporting body. The covering 20 defines, on its active face, a plurality of blocks 23 which engage the plate by contact. An important feature of the invention is constituted by the fact that the supporting body 11, in the region which is contained by the covering 20, defines a T-shaped seat 25 which constitutes means for the retention and sliding guiding of a rod-like element 26 which has connected to its own lower end a pad 27; said pad is possibly covered with soft material, has a reduced thickness, and its active face is substantially flush with the ends of the plurality of blocks 23. The covering 20 has the peculiar function of constituting a sealing element which prevents the infiltration of abrasive material in the T-shaped seat, consequently avoiding wear. For this purpose, the covering 20 is provided, in a downward position, with an opening 30 from which the pad 27 protrudes. Said opening 30 is delimited downward by an elastic lip 31 which rests above the element 26 so as to constitute a seal, and is similarly provided, on the opposite edge, with an elastic flap 32 which prevents the passage of abrasive material or dirt toward the region affected by the guides. With the described arrangement, the sliding block thus always maintains its working level, whereas it is the pad 27 that is vertically adjustable with respect to the working surface, so as to be able to engage small glass plates. This fact is very important, since the regions subjected to mutual sliding, i.e. the rod-like element 26 which slides in the guide 25, are not subjected to particular wear. To the above one should furthermore add that a roller 40 is provided at the upper end of the element 26 and has the function of engaging means for vertically positioning the pads. Said means, as more clearly illustrated in figures 7 to 9, are constituted by a pair of box-like elements, indicated by 41 and 42, which are arranged one after the other and respectively define a lower edge 41a, 42a and an upper edge 41b and 42b, which mutually converge in the central region, i.e., if the two box-like elements are seen one after the other, they respectively have a converging arrangement and a diverging arrangement. Said box-like elements 41 and 42 are articulated at their outward ends, so as to allow the vertical movement of the central ends, with the consequent shift of the position of the lower and upper tracks defined thereby. More in detail, the positioning level of the pads is determined by the vertical positioning of the central ends of the box-like elements, independently of the level assumed by the pads when the related rollers enter the region delimited by the box-like elements. In fact, if the rollers are arranged higher than the central ends, they engage the upper tracks and are lowered to the required level, whereas if the rollers are arranged lower than the central ends, they engage the lower track, consequently raising the pads. If the rollers enter the box-like elements already at the correct height, the rod-like elements in practice undergo no translatory motions. The use of two box-like elements arranged after one another allows to reverse the sliding motion of the conveyors without thereby causing problems. In order to vary the height of the central ends of the box-like elements there is a unit for adjusting the means for vertically positioning the pads, illustrated in figure 10, which in a simplified form is constituted by a vertical threaded rod 50 on which a first bevel gear 51 acts and meshes with a second bevel gear 52 which is connected to a handwheel 53, and is supported by a movable carriage 54 which, by means of pins or the like, connects to slots 56 defined on the ends of the box-like elements. The translatory motion of the carriage and of the central ends of the box-like elements connected thereto is consequently caused by acting on the handwheel. From what has been described above it can thus be seen that the invention achieves the intended aim and objects, and in particular the fact is stressed that the solution consisting in keeping at a fixed height the sliding blocks which engage the glass plates, moving only a pad which is connected to a plate-like element which can slide in guides which are arranged inside the sliding blocks and are protected outward, allows to eliminate the severe wear problems which are observed in these machines, also taking into account the fact that the area where they operate is subjected to the diffusion of abrasive material. The provision of the means for positioning the pads by virtue of a pair of box-like elements arranged after one another and having tracks which converge toward their central ends allows to reverse the movement of the traction elements, as cannot be obtained on known machines. 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 scope of each element identified by way of example by such reference signs.

Claims: Machine for machining edges, particularly of glass plates, comprising, on a supporting structure (1), a pair of opposed conveyors (2) which move continuously in a horizontal direction and retain vertically between them plates to be machined at appropriate machining heads, where at least one of said conveyors has a plurality of retaining elements (10) adjacent to each other along the moving direction of the conveyors, each comprising a supporting body (11) elongated transversely to the conveyor's motion, said elongated supporting body (11) having internal means (25) for retaining and guiding a rod-like element (26), which can slide in a direction transversely to the conveyor's motion, said rod-like element having a pad (27) connected to its lower end, said pad (27) being arrangeable at a presettable vertical distance with respect to the machining heads, characterized in that it comprises a covering (20) provided on said supporting body (11), said covering defining blocks (23) for gripping the plates to be machined, said pad (27) being arrangeable at a presettable distance from said blocks (23), which have a fixed vertical distance with respect to the machining heads. Machine according to claim 1, characterized in that said covering (20) is made of an elastically yielding material and is provided with lugs (21) which can engage corresponding holes (22) defined on said elongated supporting body (11) for the coupling of said covering (20) to said supporting body (11). Machine according to the preceding claims, characterized in that said means (25) for retaining and guiding the rod-like element (26) are constituted by a T-shaped seat (25) which is defined in said supporting body (11) and slidingly accommodates said rod-like element (26) which has a corresponding flattened configuration. Machine according to one or more of the preceding claims, characterized in that said covering (20) has, at its lower end, an opening (30) for the outward passage of said pad (27), said opening (30) being delimited, in a downward position, by an elastic lip (31) which can engage said rod-like element (26) by contact and, at the upper part, by an elastic flap (32) which can engage said rod-like element (26) by contact. Machine according to one or more of the preceding claims, characterized in that said rod-like element (26) has, at its upper end, which is opposite to the one provided with said pad (27), a roller (40) which can engage means (41,42) for positioning said pad (27). Machine according to claim 5, characterized in that said means for positioning said pad (27) are constituted by a first box-like element (41) and by a second box-like element (42) which are arranged one after the other and have a convergent orientation with respect to their respective central ends, said box-like elements (41,42) defining an upper guiding track (42a,42b) and a lower guiding track (41a,41b). Machine according to claim 6, characterized in that said box-like elements (41,42) are articulated to said fixed structure (1) at their outer ends and said central ends can be vertically adjusted so as to vary the vertical position of said pad (27). Machine according to claim 7, characterized in that it further comprises a unit for the translatory motion of said central ends. Machine according to claim 8, characterized in that said unit for varying the vertical position of said central ends comprises a threaded vertical rod (50) with which a first bevel gear (51) engages, said first bevel gear (51) engaging a second bevel gear (52) which is associated with a handwheel (53) and is supported by a carriage (54) which is connected by means of pins in elongated slots (56) which are defined respectively on the central ends of said box-like bodies (41,42). Machine according to claim 6, characterized in that said roller (40) can engage said lower (41a,41b) or upper tracks (42a,42b) of said box-like bodies (41,42) in order to vary the vertical position of said pad (27).

Inventors: BAVELLONI FRANCO, BAVELLONI, FRANCO
Applicants: BAVELLONI Z SPA, Z. BAVELLONI S.P.A.
Application year: 1991
Main classification: B24B9
IPC codes: B24B41, B24B9, B65G37