AU2010299989A1

AU2010299989A1 - An abrasive disc for a multiple disc grinding machine, in particular for processing stone and like materials, and a grinding machine including said disc

Info

Publication number: AU2010299989A1
Application number: AU2010299989A
Authority: AU
Inventors: Carlo Artina; Ferruccio Gonzo; Riccardo Pettucco; Dino Zandonella Necca
Original assignee: ADI SpA
Current assignee: ADI SpA
Priority date: 2009-09-25
Filing date: 2010-09-17
Publication date: 2012-04-26
Also published as: CA2710589A1; ES2771948T3; PL2480376T3; ITPD20090280A1; US20120225615A1; IT1395952B1; EP2480376B1; CA2710589C; WO2011036104A1; EP2480376A1

Abstract

An abrasive disc for a multiple disc grinding machine is described, comprising a disc-shaped support (Ia) having a circumferential rim (4) on which the abrasive material is placed and an opposing central hole (7) for fitting on to a driving shaft (3) of the grinding machine, said hole (7) extending through the thickness of the disc-shaped support (Ia), in which a portion of said central hole (7) has a diameter greater than the diameter of the connection to said shaft (3), such that an annular chamber (8) is formed in the thickness of the support (Ia). The further disc (1) comprises at least one radial recess (10) formed on a front surface (9) of the disc-shaped support (Ia) and extending from said annular chamber (8) towards the circumferential rim (4) of said disc, in such a way that a coolant fluid fed into the driving shaft (3) can accumulate in said annular chamber (8) and can then flow through said radial recess (10) towards the abrasive edge of said disc (1).

Description

WO 2011/036104 PCT/EP2010/063724 An abrasive disc for a multiple disc grinding machine, in particular for processing stone and like materials, and a grinding machine including said disc. Technical filed 5 The present invention relates to an abrasive disc for a multiple disc grinding machine having the features set out in the preamble of the main claim. The invention also relates to a multiple disc grinding machine including a plurality of discs of the above-mentioned type. Technological background 10 The invention is for use in particular in the sector of the processing of stone and like materials, in which use is made of multiple disc grinding machines having a plurality of cutting discs with abrasive segments combined in a pack on a shaft which may be caused to rotate. When using multiple disc grinding machines of the above-mentioned type, use is typically made of coolant fluids which are is conveyed to the processing zones to ensure that the heat generated by processing, following contact between the abrasive sectors and the surfaces of the workpiece, is adequately dissipated. In known solutions the shaft is provided with an internal hole in order to convey the fluid to a distributor member, for instance a bushing interposed between the shaft and the discs and designed to 20 collect the fluid and distribute it to the exterior of the discs in the processing zones. This solution nevertheless requires the provision of a specific distributor member which has to be mounted when the cutting discs are being mounted on the multiple disc grinding machine. Description of the invention 25 A main object of the invention is to provide an abrasive disc for multiple disc 1 WO 2011/036104 PCT/EP2010/063724 grinding machines designed to provide a coolant distribution system which is structurally simpler and easier to use, but which continues to provide efficient cooling of the tool. This object is achieved by the invention by means of an abrasive disc for a 5 multiple disc grinding machine embodied in accordance with the accompanying claims. Brief description of the drawings Other advantages and features of the present invention will become clear from the following detailed description of a preferred embodiment thereof which is 10 given with reference to the appended drawings which are provided purely by way of non-limiting example and in which: - Fig. 1 is a perspective view of an abrasive disc for a multiple disc grinding machine according to the invention; - Fig. 2 is a view in axial section of the disc of Fig. 1; 1s - Fig. 3 is a view in partial section of a multiple disc grinding machine equipped with abrasive discs according to the invention. Preferred embodiments of the invention With reference to the appended drawings, an abrasive disc for a multiple disc grinding machine embodied in accordance with the present invention is shown 20 overall by 1. A grinding machine equipped with a plurality of abrasive discs closed in a pack on a driving shaft 3 of the grinding machine which may be caused to rotate about an axis X is shown by 2. Only the cutting disc 1 will be described in detail below, as the features described mirror those of the remaining discs of the pack mounted on the shaft 3. 25 The multiple disc grinding machine designed in this way is for particular use for 2 WO 2011/036104 PCT/EP2010/063724 the processing of stone and like materials but could be used in other fields, for instance for the processing of ceramics, refractory materials or glass. The disc 1 comprises a disc-shaped support la which is axially symmetrical with a main axis shown by Y in the drawings and bears a circumferential rim 4 on 5 which abrasive cutting sectors 5 are applied. The transverse thickness of the disc at its central portion, measured parallel to the axis Y, is shown by 6. The support la is also provided with a central hole 7 for connection to an end portion 3a of the driving shaft 3 which causes the disc to rotate during cutting 10 operations involving tangential contact between the rim 4 and the material to be processed. The connection hole 7 has a first cylindrical through section 7a which comes into coupling contact with the driving shaft 3 and a second cylindrical through section 7b extending as an axial continuation of the first section, this second section 1s having a diameter greater than the first section. As a result of this feature, an annular chamber shown by 8 is formed at the location of the second through section 7b, following connection with the shaft 3, whose function will be explained in detail in the following description. The sequence of through holes 7a, 7b extends through the entire transverse thickness 6 of the disc, so that the 20 section 7b extends, with its free end, up to the location of a front transverse surface of the disc shown by 9. This surface extends with an annular configuration from the hole 7 in the direction of the rim 4 over a predetermined radial development. When the discs are mounted as a pack on the shaft 3, the surface 9 of each disc abuts against the adjacent disc and as a result of the axial 25 clamping action of the pack of discs, this surface acts as a friction member 3 WO 2011/036104 PCT/EP2010/063724 designed to prevent the relative sliding of adjacent discs. The front surface 9 is provided with at least one radial recess, shown by 10, which extends from the annular chamber 8 in the direction of the rim 4 radially including the whole surface. A preferred choice, shown in the appended 5 drawings, is to provide three recesses 10 angularly spaced from one another at regular intervals (with an angular pitch of 1200), although the invention could function with other configurations. The recesses 10 may also be readily provided on the front surface 9 by respective radial milling operations on the surface 9. As is clearly shown in Fig. 3, once the discs are positioned as a pack on the shaft 10 3, the annular chamber 8 is connected in fluid communication with each of the recesses 10 so as to ensure a passage for a coolant fluid accumulated in the chamber and conveyed to the exterior of the disc via the recess 10. The driving shaft of the grinding machine 2 is provided with an internal axial duct 11 for supplying the coolant fluid, which duct is continued by one or a 1s plurality of radial end ducts 12 opening at the location of cylindrical shell of the end portion of the shaft 3 designed to house the abrasive discs. It is advantageous for the thickness 6 of the disc 1 in contact with the shaft to be smaller than the diameter of the hole 12 provided on the shaft, so as to ensure a passage for the coolant fluid from the chamber 8 containing the fluid to 20 the recesses 10, which recesses 10 therefore form a kind of channel for supplying the fluid to the exterior of the disc in order to distribute the fluid to the processing zones close to the abrasive sectors of the circumferential rim 4. The provision of the annular chamber 8 in fluid connection with the recesses 10 therefore makes it possible for the coolant fluid to be accumulated in the 25 chamber and then to flow radially, under the centrifugal effect of the rotation of 4 WO 2011/036104 PCT/EP2010/063724 the grinding machine, along the recesses so as efficiently to reach the processing zone of the abrasive sectors of the discs and thus to ensure the cooling of the surfaces in relative contact of the discs and the material being processed. In a variant of the invention the cylindrical shell of the driving shaft 3 intended 5 to receive the cutting discs, may be provided with a groove 13 (or a plurality of grooves 13) extending axially along the whole pack of discs and in fluid communication with the supply holes 12 of the coolant fluid. This groove may improve the distribution effect of the coolant fluid to each annular chamber of the discs mounted in a pack on the shaft, as shown in Fig. 3, in the lower axial 10 section of the grinding machine. The invention thus achieves the objects set out above and provides many advantages over known solutions. A main advantage lies in the simpler structure and operation of the cooling system which the invention applies to multiple disc cooling systems, avoiding the is use of specific distribution members for the coolant fluid, such as the bushings or like distributors for which known solutions make provision. This simpler structure is advantageously reflected by easier use, especially as regards operations to mount the pack of discs on the grinding machine and remove it therefrom, a major advantage when taking account of the fact that these tools have to be 20 readily and rapidly interchangeable as a result of the wear of the abrasive profiles to which they are subject when processing materials. 5

Claims

1. An abrasive disc for a multiple disc grinding machine, comprising a disc-shaped support (1a) having a circumferential rim (4) on which the abrasive material is placed and an opposing central hole (7) for fitting on to a driving 5 shaft (3) of the grinding machine, said hole (7) extending through the thickness of the disc-shaped support (la), characterized in that - a portion of said central hole (7) has a diameter greater than the diameter of the connection to said shaft (3), such that an annular chamber (8) is formed in the thickness of the support, 10 and in that it comprises at least one radial recess (10) formed on a front surface (9) of the disc-shaped support (la) and extending from said annular chamber (8) towards the circumferential rim (4) of said disc, in such a way that a coolant fluid fed into the driving shaft (3) can accumulate in said annular chamber (8) and can then flow through said radial recess (10) towards the abrasive edge of 1s said disc.

2. A disc according to claim 1, in which three radial recesses (10) are provided on said front surface (9), these recesses being spaced apart angularly at regular intervals.

3. A disc according to claim 1 or 2, in which said portion of the central 20 hole (7) forming said annular chamber (8) extends as a continuation of a portion of the hole (7) intended to contact the driving shaft (3) of the grinding machine when the disc is connected to it.

4. A multiple disc grinding machine comprising a driving shaft (3) designed to receive a plurality of abrasive discs (1) combined in a pack on said 25 shaft (3), each of said discs being in accordance with one or more of the 6 WO 2011/036104 PCT/EP2010/063724 preceding claims.

5. A multiple disc grinding machine according to claim 4, in which said driving shaft (3) comprises at least one hole (17) for the feed of coolant fluid, the hole extending radially in the end portion of said shaft (3) which is intended 5 to receive the plurality of cutting discs (1), and opening on the cylindrical shell which comes into contact with the discs, in which the transverse thickness of the discs is smaller than the diameter of said at least one coolant fluid feed hole (12) in the shaft, so as to permit the passage of fluid from said feed hole (12) to the annular chamber of the corresponding disc and thence to the corresponding 10 recess (10).

6. A multiple disc grinding machine according to claim 5, including at least one groove (13) extending axially in the cylindrical shell of the end of the driving shaft intended to be connected to said discs, said groove (13) communicating with said radial hole (12) for the feed of the coolant fluid and 1s being capable of bringing said hole (12) into communication with the annular chambers (8) of the corresponding discs (1) which are fixed in a pack on the driving shaft (3). 7