Patent GB-718910-A (GB)
Title: Improvements in or relating to a method and apparatus for polishing glass
IPC: B24B7/24
Filed: 1951-12-04
Abstract: 718,910. Grinding or polishing flat glass. PITTSBURGH PLATE GLASS CO. Dec. 4, 1951, [March 14, 1951.] No. 28393/51. Class 60. ' Apparatus for polishing a substantially continuous glass sheet 2, Fig. 4, comprises a number of pairs of vertically disposed opposing and axially aligned rotating felt runners 45 spaced longitudinally of the horizontal path of travel of the glass moving between them, fluid pressure means acting on each felt for imposing equal and opposite pressures upon the glass between each pair of axially aligned felts, and means for selectively feeding rouge to the felt. Each runner is bolted to a hollow spindle 27, Fig. 7, driven through reduction gearing by an electric motor 86, Fig. 3. The spindles of the upper runners are mounted in anti-friction bearings in a member 7 disposed transversely of the path of travel of the glass while those of the lower runners are similarly mounted in a member 8. The two members 7, 8 are mounted on flanged rollers carried by a carriage 5 and a stand 6. The carriage is fitted with wheels 11 to run on rails 12 and is provided with clamping members 13. To reciprocate the two members in synchronism transversely of the glass a crank and connecting rod mechanism is connected between each member and the carriage 5, the two cranks being driven by a single motor or by separate synchronized electric motors mounted on the members 7 and 8. The glass is fed horizontally between the successive sets of runners by rollers 4, Fig. 4, which are covered with perforated rubber to grip the glass and are wider than the latter in order that the ends of the covering may form flanges to guide the glass when pressure is applied. A cooling medium, such as water, is fed to the glass by units 3 which comprise perforated pipes 112, Fig. 12, and spring-loaded squeegee members 108 which wipe the glass substantially dry to prevent dilution of the rouge fed to the runners. The water escapes from the unit over the edges of the glass and is collected by a trough 117. The supply of rouge to each runner is controlled by a needle valve 66, Fig. 7, which is actuated by a solenoid 75 in circuit with the driving motor 86 so that when the torque on the latter increases due to increased frictional resistance between the runner and the glass the valve is lifted to allow rouge to flow on to a deflector member 73 and thence to the runner and the glass. The rouge is kept in circulation in a chamber 64 by pipes 83, 84. The felt of each runner is provided with channels 57, 58, Fig. 6, to distribute the rouge and is secured on its outer and inner peripheries to diaphragms 47, 48 bolted to the runner 45. These diaphragms and a flexible backing plate 59 enable the felt to be subject to pressure from an air line 40 or to vacuum from a line 41 when the felt is to be lifted from the glass to clear the apparatus. Pipes 53 connect the lines to the runners. The spindles of the runners may be axially adjusted in relation to the members 7 and 8 by screw jacks 91, Fig. 4, which are connected to hand wheels 102 by chain drives. The glass may be fed through the apparatus as a continuous ribbon or as a series of sheets in abutting relation.