Patent GB-1474317-A (GB)
Title: Grinding machine with a rest apparatus and a method of grinding
IPC: B24B41/06
Filed: 1975-02-12
Abstract: 1474317 Grindings TOYODA KOKI KK 12 Feb 1975 [12 Feb 1974] 6045/75 Heading B3D A grinding machine comprises a work support means 37 to rotatably support a workpiece W, a wheel support 13 to rotatably support a grinding wheel 14, rest means 40 to support the workpiece and to bend same towards the grinding wheel, means to advance the wheel support automatically through a predetermined feed amount for a preliminary grinding operation and to stop same automatically at a predetermined position while maintaining engagement between the wheel and workpiece, means to advance the rest means automatically through a predetermined feed amount for bending the workpiece towards the grinding wheel while the wheel support is stopped and to stop the rest means automatically so that the workpiece is ground by the wheel with a predetermined stock removal being left, and means to re-advance the wheel support automatically after stopping the rest means for grinding the workpiece until it ceases to engage with the rest means. The grinding wheel 14 is belt driven from a motor 16 and mounted on the support 13 movable towards and away from the workpiece along guideways 12 on a base 11 fixed to the bed 10 of the machine. A nut 23 depends from the support 13 and is engaged by an infeed screw 22 rotatable in but axially fixed to a piston 21 of a rapid feed cylinder 20. A gear 24 fixed to the infeed screw is connected by gears 25, 26, 27 to a pulse motor 33 for effecting a fine feed of the grinding wheel. The workpiece W is supported between supports 37 on a swivel table 38 carried by a slide table 36 movable along ways 35 on the bed 1 by a cylinder 39. The rest means 40 has a body 42 movable towards and away from the workpiece on a base 41 by a cylinder 43. A pair of rods 44a, 44b are axially slidable in the body 42, the upper rod having a feeler 45a for horizontally supporting the workpiece, and the lower rod being pivotally connected to an L-shaped arm 46 having a feeder 45b for vertically supporting the workpiece. The rods are engaged by oppositely-handed screws 48a, 48b which are interconnected by gears 49a, 49b driven by reduction gearing from a pulse motor 51. An automatic gauge 54 is disposed at the front of the body 42 and has feelers 55, 56 which engage the workpiece and actuate a differential transformer. In operation, the wheel is advanced at a rapid feed by actuation of the cylinder 20 to a position A whereupon pulses are supplied to the motor 33 at a relatively high frequency to advance the wheel at a rough grinding speed, the number of pulses being counted until they reach a preset number and the advance is stopped at a point B. The cylinder 43 is then actuated to advance the rest 40 so that the feelers 55, 56 of the gauge engage the workpiece, the feelers 45a, 45b remaining out of engagement with the workpiece. At the advanced position C of the rest, the motor 51 is supplied with pulses so that the feelers 45a, 45b are advanced at rough grinding speed to engage the workpiece and bend it towards the grinding wheel so as to be ground thereby until the number of pulses supplied to motor 51 equals a preset number and the advance is stopped at a position D. The wheel is then advanced again to effect rough grinding to a position E and the workpiece has a good roundness, the workpiece after point F is reached being unsupported by the rest. Pulses are then supported at a low frequency to motor 33 to advance the wheel at a fine grinding speed and the workpiece is reduced to a first predetermined size as indicated by the gauge 54 and the support 13 is stopped at point H, the rest then being advanced at the fine grinding speed by pulses supplied to motor 51 to bend the workpiece and cause it to be ground by the stationary grinding wheel until it reaches a second predetermined size as detected by the gauge and the advance of the rest is stopped at point J. The grinding wheel is again advanced at a fine grinding speed from point K to reduce the size of the workpiece until it is unsupported by the rest (point L) and reaches its final size and the advance of the wheel is stopped at point M, spark out continuing to point N where both the wheel and rest are retractive.