method for grinding and polishing of glass in the plain areas

摘要

267,654. Pilkington Bros., Ltd., and Waldron, F. B. Jan. 13, 1926. Flat extended surfaces, surfacing; guides and rests; spindle mountings; wheels.-Glass issuing from a tank 1 is formed into strip 2 at 1a, and passing through a lehr 3, is fed by rollers 4 to apparatus which grinds and polishes both faces of the sheet simultaneously; alternatively the sheet may be cut up into plates at 3a, subsequently being ground and polished on both faces simultaneously. The grinding and polishing apparatus consists of a series of upper and lower runners, the glass being moved therebetween by lower rollers 7 and upper rollers 8. Each lower grinding-runner comprises nogs 5a carried by a disc 12 mounted on a vertical hollow shaft 9 running in bearings 10 in a tube 11 slidable in a casing 13, a casing 16 secured to the tube 11 enclosing bevel gearing 17, 18 for driving the shaft; the weight of the casing 11 &c. is counterbalanced by a weight 27, and the runner may be raised or lowered by operation through bevel gearing 23, 24 of a nut 22 engaging a screwed rod 20 fixed to the casing 16. Water and abrading-material are fed to a casing 31 and thence through the shaft 9 to the runner. The upper runners are similar to the lower runners, but are supported by adjustable rods 20 screwed to engage adjusting nuts 22; for rapid lifting, levers 34 are employed. The lower rollers 7 are each driven through worm and chain gearing 51 - - 54 and are carried by a pair of frames 38 carried by guide rods 39 and connected by a link 40 to a lever 41 having an arm 42 carrying a weight 45, and having a pointer 46 moving over a scale 47; wear of the grinder may be compensated for by adjustment of the nut 22 to bring the pointer back to a given position. An automatic electric device, Fig. 3, may be employed for compensating for wear comprising a fixed contact 58 and a contact 57 on the lever 42, which as the roller 7 falls due to wear of the grinder, come together and close the of a solenoid 60, which moves a lever 61 to close the circuit of a motor for driving the nut 22. The roller 8 is carried by a frame 48 sliding on the guides 39, springs 49 moving the frames 38, 48 in opposite directions. The shaft of the upper roller is solid, water &c. being supplied externally. The grinding-runners have the outer row of nogs formed with a perpipheral ring to retain abrasive etc.; a ring shield may be employed in place of forming the nogs integral with the shield, and a ring may be employed similarly with the polishing-runners. The polishing-runners have several heads on a frame, the tubular shaft having tubular extensions approaching the heads to apply the water &c. close to the heads. In a modification, the glass lies in a vertical plane during grinding, &c., the runners having their shafts horizontal, rollers supporting the glass at its lower edge. Guide rollers also may be employed above the glass, and in the first constructional form may be employed at the side edges of the glass.