Patent GB-884658-A (GB)
Title: Improvements in or relating to an apparatus for grinding or polishing glass sheets
IPC: B24B7/24
Filed: 1958-04-11
Abstract: 884,658. Grinding and polishing glass. COMPAGNIE DE SAINT GOBAIN. April 11, 1958 [April 11,1957; Oct. 3,1957],No. 11644/58. Class 60. An apparatus for grinding or polishing glass sheets 1, Fig. 5, comprises a rubbing tool 2 actuated by two driving members 7, 12 which are themselves driven synchronously and in phase, one of the members 7 being directly coupled to the tool to cause a point on the tool to describe a curved direction, and the other member 12 being coupled to the tool through a mechanical linkage so as to accommodate changes in the distance between the points of application of the driving forces to the tool. As applied to a machine for grinding or polishing both surfaces of a glass sheet, each upper and lower tool is, at one end, connected by. pins 9, 10 to a member 8 mounted on an eccentric portion 7 of a common vertical shaft 6, the eccentric portions being displaced on the shaft by 180 degrees. The other ends of the tools are connected by pins 14 to the members 13 which are also mounted on eccentric portions 12 displaced by 180 degrees from each other on a common vertical shaft 11 which is driven synchronously with the shaft 6 from a single shaft or from separate synchronous motors so as to impart circular translational movements to both tools, one of which is 180 degrees out of phase with the other. Expansion of the tools caused by friction is accommodated by relative pivotal movement between the tools and members 13. The tools are provided with circular pads 22, Fig. 6 which slidably engage similar pads 21 having cylindrical portions 23 co-operating with plates 19, 20 arranged to press the tools against the glass; the plates 19, 20 are stationary, relative movement between them and the tools being permitted by sliding movement between the pads 21, 22. Each corner of each plate 19, 20 engages a rod 24, Figs. 5 and 6, disposed within a bracket 25 secured to a concrete block 26, the lower plate 20 being vertically adjustable by rotation of the rods 24 by means of a worm and wheel 28 vertically displacing nuts 29 below the plate. The nuts have projections 30, Fig. 7, which are pinned to stirrups 36 arranged to engage projectives 35 on hydraulic jacks 33 disposed on the upper plate 19. When necessary, the tools may be removed from the apparatus in the direction of the arrow Fl after removal of the pins 9, 10, 14. After the tool is replaced, the lower plate 20 is raised by synchronous electric motors driving the wheels 28 to rotate the rods 24 until the tool 4 bears against the glass, individual manual adjustment of the wheels 28 being possible for the final setting. The upper plate 19 is then positioned above the copper tool 2, the jacks 33 placed on the plate, and the stirrups 36 engaged with the projections in the jacks. Fluid pressure is then applied to the spaces 32 in the jacks to provide the necessary pressure between the plates 19, 20 which is then transmitted to the tools; vertical movement between the tools 2, 4 and members 8, 13 is possible to compensate for different thicknesses of glass and for wear of the tools. In another embodiment, the rubbing tool 38, Fig. 9, is driven in a circular translatory movement by cranks 41, 42 carried by rods 39, 40 synchronously driven by a shaft 61 and gear wheels 50, 51 from a motor 60. The crank 41 is directly coupled to the tool by a pin or screw 43 and the crank 42 similarly connected to a block 47 slidable in ways 48 formed on the tool; expansion of the tool due to heating caused by friction being permitted by movement of the block relative to the ways 48. In order to impart the drive from the crank 42 to the tool when the crank is normal to the direction of the slides, the block 47 may be resiliently located between springs 63, Fig. 11, adjustably connected to shoulders 62 formed at the ends of the ways. The tool may be raised or lowered by levers 56, 57 having forked ends engaging pins on the rods 39, 40. Specification 884,657 is referred to.