Bilateral abrasive disc pad

Abstract

A bilateral abrasive disc pad is provided comprising a cylindrical mounting section, an inner annular section, and an outer annular section to which abrasive flaps are attached in an overlapping relationship. The cylindrical mounting section has a central screw-threaded mounting hole for threadedly connecting to a threaded driven shaft of a grinder. The outer annular section of one side is flat, while the outer annular section of the opposing side is convex. The cylindrical mounting section is substantially thicker than the outer annular section such that the ratio of the mass of the outer annular section to the mass of the combination of the cylindrical mounting section and the inner annular section is 2 to 1 or less. Such thickening of the central mounting section reduces runoff and vibration caused by uneven wear of the abrasive flaps and allows the pad to be securely attached to the shaft of the grinder without the need for a mounting nut.

1 . A double-sided, rotatable abrasive pad, comprising:
 a cylindrical mounting section having a mounting hole concentrically arranged around an axis of rotation of the pad;   an inner annular section connected around the circumference of the cylindrical mounting section, and   an outer annular section connected around the circumference of the inner annular section and having opposing sides, each side being configured for the affixing of overlapping abrasive flaps,   wherein the outer annular section of one side is parallel to a plane orthogonal to an axis of rotation of the disc, and the outer annular section of the opposing side is oriented at an angle to the orthogonal plane so as to form a convex frustro-conical surface.   
     
     
         2 . The double-sided rotatable abrasive pad defined in  claim 1 , wherein the mass per unit radial length of the combination of the cylindrical mounting section and the inner annular section is greater than the mass per unit radial length of the outer annular section. 
     
     
         3 . The double-sided rotatable abrasive pad defined in  claim 2 , wherein ratio of the mass of the outer annual section to the mass of the combination of the cylindrical mounting section and the inner annular section is 2 to 1 or less. 
     
     
         4 . The double-sided rotatable abrasive pad defined in  claim 3 , wherein the radial length of the combination of the cylindrical mounting section and the inner annular section is about equal to the radial length of the outer annular section. 
     
     
         5 . The double-sided rotatable abrasive pad defined in  claim 1 , wherein a thickness of the cylindrical mounting section along an axis of rotation is substantially greater than a thickness of the outer annular section along the axis of rotation, and wherein the mounting hole is screw-threaded for receiving a screw-threaded driven shaft. 
     
     
         6 . The double-sided rotatable abrasive pad defined in  claim 5 , wherein the thickness of the cylindrical mounting section is about twice as much as the thickness of the outer annular section. 
     
     
         7 . The double-sided rotatable abrasive pad defined in  claim 1 , wherein the opposing side of the outer annular section is oriented between about 10° to 20° relative to the plane orthogonal to an axis of rotation of the disc. 
     
     
         8 . The double-sided rotatable abrasive pad defined in  claim 1 , further comprising a first plurality of abrasive overlapping flaps of uniform size and shape affixed to the outer annular section of one of the sides of the pad and a second plurality of abrasive overlapping flaps of uniform size and shape affixed to the outer annular section of the opposite side of the pad, wherein the extent of overlap of the abrasive flaps of both pluralities is no more than about half of a circumferential extent of the flaps. 
     
     
         9 . The double-sided rotatable abrasive pad defined in  claim 8 , wherein the coarseness or fineness of the of the abrasive properties of the first and second pluralities of abrasive flaps are different. 
     
     
         10 . A method of using the double-sided rotatable abrasive pad of  claim 5 , comprising the steps of:
 screwing the abrasive pad to a driven rotatable shaft having an exterior screw-thread engageable with the screw-thread of the mounting hole;   rotating the rotatable shaft in a direction that tightens the screw thread engagement between the pad and the driven shaft;   abrading a workpiece with a first of the opposing sides of the outer annular section;   unscrewing the pad from the driven shaft, turning the abrasive disc 180°, and re-screwing the pad to the driven shaft;   rotating the rotatable shaft in a direction that tightens the screw thread engagement between the pad and the driven shaft, and   abrading a workpiece with a second of the opposing sides of the outer annular section.