Patent GB-760878-A (GB)
Title: Tile sizing machine and method
IPC: B27M3/00
Filed: 1954-09-20
Abstract: 760,878. Grinding tiles. ROBBINS, E. S. Sept. 20, 1954, No. 27134/54. Class 60 A machine for reducing tiles to correct size comprises a plurality of work holders 23 each arranged to clamp a stack of tiles in position and carried by a turret 11 which is rotatated by a motor 19 so as to pass each stack of tiles between an opposed pair of grinding members 53 for operating upon opposite edges of the tiles; a stack of tiles is loaded into each work holder when it arrives at a loading station (shown at the lower part of the plan view of Fig. 4) and is there acted upon by means 42 for aligning the edges of the stack. The. turret 11 is carried by a hollow shaft 12 which is rotated from the motor 19 through a belt-andpulley drive 17. The motor is controlled by a normally open switch 78 and a switch 86 arranged to be held open whenever a work holder is at the loading station (which is at the left in Fig. 7) by one of a series of arms 87 provided on the turret. Each work holder consists of a base plate 24, upstanding plate 26 and clamp plate 27 which is pivoted on a rocker arm 29 adapted to apply and release clamping pressure under the control of a connecting rod 34 operated by a piston-and-cylinder device 32. Fluid pressure supplied to one end of the hollow shaft 12 is delivered to one end or the other of each of the devices 32 under the control of a solenoid-actuated valve 39. For most of the travel of the work holder, the valve is deenergized and clamping pressure applied; when the work holder arrives at the loading station, pressure is relased by energization of the solenoid valve because the contacts 80, Fig.7, of the solenoid are at that point closed by brushes 82 in a power circuit including a, normally closed switch 77. The grinding members 53 consist of a pair of drums each mounted on a shaft 54 and rotated through a belt-and-pulley drive 58 by a motor 61. To permit adjustment of the drums to and from each other, the bearings 55 of each shaft 54 are carried by a pair of parallel rods 56 having screwthreaded means 64 for adjusting them longitudinally by a hand-wheel 70; clamping screws 63 secure the rods in adjusted position. The aligning means at the loading station consists of a pair of plates 42 for engaging the opposite edges of a stack of tiles loaded on to a work holder at this station and each mounted for sliding movement to and from the stack by a piston- and-cylinder device 47 controlled by a solenoid-actuated valve; removable stops 75 of a size appropriate to the size of tile being treated are provided for limiting the inward movement of the plates 42. To operate the machine, a stack of tiles is placed in the work holder at the loading station with the turret at rest. After operation of the plates 42 to align the stack, the switch 77 is opened to de-energize the solenoid valve 39 of the workholder and thereby clamp the stack in position. The switch 78 is then momentarily closed to start the turret motor 19 and energize a solenoid, 88 to release a brake band 90 from engagement with the shaft 12 so that the turret rotates until the next work holder arrives at the loading station and the corresponding arm 87 then actuates the switch 86 to stop the motor and apply the brake; the clamping plate 27 of that work holder is also released by the action of the brushes 82 and the stack of tiles either removed or turned through a right-angle for the finishing of the other edges.