Abrasive tools and methods of making same

Abstract

Abrasive tools of the disposable type applicable to many types of equipment to sand materials of various types are provided. In particular, the invention relates to devices using rotating abrasive discs for sanding machines, which include a plurality of flexible abrasive discs open at a radial cut and arranged in an overlapping and staggered configuration such as to define an abrasive, lamellar-like work surface with overlapping flaps, wherein each flap is formed of a protruding portion of an abrasive disc. Methods of making such abrasive tools are also provided.

1 - 14 . (canceled) 
     
     
         15 . An abrasive tool for sanding machines, comprising a plurality of flexible abrasive discs open at a radial cut and arranged in an overlapping and staggered configuration such as to define an abrasive, lamellar-like work surface with overlapping flaps, wherein each flap comprises a protruding portion of an abrasive disc. 
     
     
         16 . The abrasive tool of  claim 15 , wherein each abrasive disc comprises a central hole from which a plurality of slots extend in a spoke pattern, so as to form tongues positioned around the hole. 
     
     
         17 . The abrasive tool of  claim 15 , wherein said radial cut extends between the peripheral rim of a disc and its central hole. 
     
     
         18 . The abrasive tool of  claim 15 , wherein said flexible abrasive discs comprise a backing having a binding agent to which a suitable abrasive powder adheres. 
     
     
         19 . The abrasive tool of  claim 18 , wherein said backing comprises paper, preferably weighing 70 to 300 g/m 2 , or canvas or canvas/paper; or said backing is made from semi-rigid plastic material or a thin and flexible sheet of metal, such as aluminium. 
     
     
         20 . The abrasive tool of  claim 18 , wherein said backing comprises the male or female element of a velcro fastening system on the opposite side to the abrasive side, so as to permit its removable attachment to the polishing pad of a sander comprising the complementary velcro element. 
     
     
         21 . The abrasive tool of  claim 20 , wherein said abrasive discs are replaced by half-moon abrasive elements, each abrasive half-moon element comprising an abrasive surface and an opposite velcro surface, of the female or male type, such velcro surface being destined to cling to a velcro surface of the complementary type attached to the polishing pad of a sander. 
     
     
         22 . The abrasive tool of  claim 18 , wherein said abrasive powder is selected from the group consisting of: diamond, corundum, quartz, silica, pumice, sandstone, emery, garnet and any combination thereof; or a synthetic powder selected from the group consisting of: aluminium, chrome, iron, zirconium oxides, boron nitride, silicon carbide, glass, boron carbide, ceramic-coated aluminium oxide and any combination thereof. 
     
     
         23 . The abrasive tool of  claim 18 , wherein said binding agent is selected from the group consisting of: natural glues, ureic resins and phenolic resins. 
     
     
         24 . The abrasive tool of  claim 15 , wherein said abrasive disc or said half-moon abrasive element comprises a plurality of through holes on its surface. 
     
     
         25 . The abrasive tool of  claim 15 , wherein the abrasive discs or abrasive half-moon elements have a different grain, preferably increasing or decreasing in succession. 
     
     
         26 . The abrasive tool of  claim 15 , wherein the abrasive discs the same or different from each other, have an abrasive surface which has separate portions of a different grain. 
     
     
         27 . A Method of making an abrasive tool comprising the following steps:
 providing a plurality of flexible abrasive discs having a central hole and a radial cut which extends from the peripheral rim of a disc and its central hole, said radial cut having a first and a second rim;   stacking said abrasive discs, aligning the respective radial cuts;   bending said abrasive discs together so as to bring the first rims, destined to form the working rims of the tool, into an offset position from the opposite second rims;   rotating the lowest disc in the stack around an axis perpendicular to the disc and passing through the centre, then in succession rotating all the other discs from the bottom to the top, so as to achieve a staggered configuration which gives rise to the lamellar-like abrasive work surface.   
     
     
         28 . A method of renewing the worn abrasive work surface of an abrasive tool, comprising the following steps:
 removing the worn flaps or just the portion thereof comprising the edge; and   if necessary, rotating the lowest disc in the stack around an axis perpendicular to the disc and passing through the centre, then in succession rotating all the other discs from the bottom to the top, so as to achieve a staggered configuration.