GB857978A - Improvements in process and apparatus for the manufacture of small glass tiles - Google Patents

Abstract

857,978. Glass tile manufacture. BAZZANO, V., BAZZANO, P., and PEROTTI, F. Feb. 13, 1959 [Feb. 15, 1938. No. 5125/59. Class 56. In the manufacture of small glass tiles for use as tesserae for mosaics and for the covering of walls and floors, the tiles are made by pressing them one by one in small moulds in steps. The pressing machine comprises a stepwise rotatable horizontal table 1 with a series of vertical holes 7 in which extensions 108 of open-top funnel shaped moulds 8 are seated. A plunger 9 slides in each mould 8 and has a stem 109 extending through and beyond the extension 108. The moulds 8 and plungers 9 may have any desired cross-section and the plungers 9 may have a projecting centre section with undercut opposed edges for forming tiles with undercut sides to give greater grip when set in mortar. Each mould 8 is fed with a gob of glass 110 through a funnel 12 at station A which is allowed to set and cool to pressing temperature at stations B, C, D, E. At each station F, G and H the glass is pressed between a cover plate 22 and a compressing device 23 mounted on the machine frame 3 below the table 1. The device 23 comprises a guide 25 in which slides a hut 26 with a tubular extension 126 on which is mounted a depending tubular extension 128 of a hollow plunger head 28, a coil spring 27 bearing against the hut 26 and the head 28. A hammer block 29 is mounted on a coil spring 30 within the extension 126, 128 and the head 28. The hub 26 is reciprocated by a roller 32 on stem 226 engaging a cam 31 on shaft 106 rotated from the main shaft, a spring 34 between the frame 3 and a plate 33 on the stem 226 maintaining the roller 32 on the cam 31. The cam 31 just raises the head 28 into contact with the extension 108 of mould 8 and raises the mould 8, as in Fig. 6, into contact with the cover plate 22 which is adjustably mounted on a support 21 by a screw 24. The nut 26 is then raised rapidly to telescope the extensions 126, 128 to throw the hammer block 29 against the stem 109 and the plunger 9 presses the glass 110 against the cover plate 22. The parts during the pressing are cooled by an air nozzle 35. The force of the pressing is greatest at station F and is decreased at G and H so that the almost hard glass may not crack. The pressing time is short and the table can be rotated at a greater rate, allowing a high number of steps, from 8,000 to 12,000, an hour. The pressed tiles 10 after leaving station H are allowed to cool from stations I to S, the stems 109 riding on the low section 137 of a fixed cam 37 which maintains the tiles 10 substantially flush with the tops of the moulds 8, cooling air nozzles 36 being provided. At station T, the stems 109 ride onto a high section 237 of cam 37 and the raised tile 10 is blown by an air jet from nozzle 38 on to a shoot 39 or a brush ejection may be used. The moulds 8 may have lateral grooves for clearing by air jets 40 while the plungers 9 are still raised at stations U, V, Wand' at station X a pusher 43 positively returns the plunger 9 to the bottom of mould 8.