Patent GB-1211751-A (GB)
Title: Improvements in or relating to surfacing
IPC: B24B7/12
Filed: 1968-01-10
Abstract: 1,211,751. Surfacing wheel. ENGLEHARD HANOVIA Inc. 10 Jan., 1968 [12 Jan., 1967], No. 1505/68. Heading B3D. A wheel for surfacing a flat material, which wheel, in use, is rotated about an axis of rotation inclined to the normal of the surface of the flat material, has mounted thereon or integral therewith a plurality of satellite surfacing means each having substantially co-planar abrasive elements which, in use, abrasively engage the material being surfaced when the material is moved in a plane transverse to the axis of rotation of the wheel, the satellite surfacing means being disposed about the axis of rotation of the wheel and being spaced apart from each other and the axis of rotation of the wheel, the abrasive elements lying in an outer annular zone and an inner annular zone concentric about the axis of rotation of the wheel, the total engageable area of all of the abrasive elements lying in the inner annular zone relative to the total area of the inner annular zone being greater than the total engageable area of all the elements lying in the outer annular zone relative to the total area of the outer annular zone, and the total engageable area of all the abrasive elements lying in the inner annular zone being greater than the total engageable area of all the abrasive elements lying in the outer annular zone, the arrangement being such that, upon rotating the wheel about the axis of rotation and moving the material to be surfaced in a plane transverse to the axis of rotation of the wheel in abrasive engagement with the wheel, he abrasive elements lying in the outer annular zone abrasively engage the material being surfaced as the material first contacts the wheel to perform a first surfacing operation upon the material, and the abrasive elements lying in the inner annular zone abrasively engage the material being surfaced as the material contacts the wheel for a second time after having passed through the axis of rotation of the wheel to perform a second surfacing operation upon the material. A flat sheet 14, e.g. of plate glass, is traversed past a surfacing wheel 10 rotated about an axis 12 inclined to the normal to the surface of the sheet and having five surfacing means 11 mounted on the wheel structure so as to be non-rotatable about their centres. Each surfacing means comprises sections 21-27 disposed about a centre 28. Each section has abrasive elements 31 comprising abrasive particles, e.g. diamond, or predetermined size or within a predetermined size range, in predetermined concentration in a metallic or resinoid matrix, the elements being mounted on a backplate 32. The elements are spaced sufficiently to facilitate the distribution of coolant flow generally radially outward from a source preferably located in the central region of the wheel. Sections 21-26 are 45 degree sections. Section 27 is a 90 degree section bounded by a a line 34 which is an arc about the axis of rotation 12.  The abrasive elements 31 of section 27 contain abrasive particles, e.g. diamonds, of size 5-30 microns and concentration Cc, e.g. 2À1 carats/ cu. inch. The abrasive elements 31 of sections 25, 26 contain abrasive particles in lower concentration C B , e.g. 1À7 carats/cu. inch and the abrasive elements 31 of sections 21-24 contain abrasive particles in lowest concentration C A , e.g. 1À3 carats/cu. inch. Zones I-V thus have respectively concentrations C A ; C A +C B ; C B ; C B +C C ; C C . When the surfacing wheel 10 is broken-in, a ridge 15 is formed dividing the contact area of each of the surfacing means 11 into outer and inner portions 16, 17. With the sheet 14 being fed in the direction of the arrows, it first comes into abrasive engagement with the outer portions 16, the inner portions 17 not engaging the material; thus a first surfacing operation is performed by the zone I of concentration C A . The sheet then passes through the axis of rotation 12 and comes into abrasive contact with the inner portions 17. As the sheet first comes in contact with an inner portion 17 approximately at the arcuate line 34, it is engaged by the zone V with the highest concentration. As it moves, it is engaged by the zone IV, coming into contact with more and more of concentration C B  and progressively less of concentration C C . The sheet then progressively passes through zones III, II and probably a part of I before losing contact at the ridge 15. In a modification, a substantially flat unitary surfacing wheel contains a plurality of integral satellite surfacing means constituting raised portions having co-planar abrasive elements.