GB1387537A - Grinding machine - Google Patents

Abstract

1387537 Grinding; toneing grinding wheels TOYODA-KOKI KK 25 Oct 1973 [28 Oct 1972] 49789/73 Heading B3D A grinding machine comprises a workpiece supporting means 37 mounted on a bed 10 on which is slidably mounted a wheel slide means 13 having at least one motor driven grinding wheel, wheel slide actuating means for moving the wheel slide towards and away from the workpiece, and dresser means 44 movable towards and away from the grinding wheel. Dresser feed means 47, 49 feed the dresser means towards the grinding wheel by a predetermined amount, any actuating means move the dresser means to perform a dressing operation on the wheel. Position determining means has shiftable means 63 supported by and movable with the wheel slide means, and drive means serve to move the shiftable means an amount corresponding to the predetermined dressing amount in a direction of retraction of the wheel slide means whenever dressing is performed. Means 66 for detecting a position of the wheel slide in co-operation with the shiftable means generates a signal serving to stop the movement of the wheel slide means whereby the wheel slide means can be accurately positioned at the position thereof which must be varied in accordance with a reduction of the grinding wheel by dressing operations thereon. The wheel slide is slidable along guideways 12 on a base 11 fixed to the bed 10 and is rapidly advanced towards the workpiece or by movement of a piston 21 in a cylinder 22, the piston being axially secured to a rotatable screw 22 engaging a nut 23 on the wheel slide. The workpiece is mounted in a workhead 37 on a swivel table 38 carried by a work slide 36 movable along guideways 35 on the bed by a cylinder device 39. The screw 22 has dogs 25, 26 which co-operate with limit switches LS1, LS2 determining the limits of the advance-and retraction of the rapid feed. A gear 24 is secured to the screw 22 and is connected by gears 29 ... 34 to a stepping motor 33 which adjusts the wheel slide to compensate for a dressing operation before the start of a grinding operation. A body 40 of a dressing device is mounted on the wheel slide 13 and slidably supports a ram 41 carrying a mount 43 for a rotary dresser 44 driven by an hydraulic motor 45. A sleeve 51 is rotatably mounted in the ram and is engaged by the screw-threaded portion 50a of a feed shaft 50 connected to a piston 49 slidable in a cylinder 48 for a rapid advance of the rotary dresser. A gear 52 is secured to the feed shaft 50 and is driven by a rack-and-pinion mechanism and worm gearing for effecting an advance of the dresser after the rapid advance to dress the wheel to a predetermined depth according to an infeed means. A worm-wheel 53 is keyed to sleeve 51 and is engaged by a worm 57 which also engages a second worm-wheel 55 keyed to a shaft 54 having a screw thread portion 54a engaging a nut 61 on a shaft 62. The worm 57 is secured to a shaft 56 connected by bevel gearing to an infeed means 60 having an intermittent motion mechanism. The shaft 62 adjustably carries the original position indicating dog 63 which co-operates with a pivoted lever 66 to operate a detector 20. A limit switch 71 acts in the event of excessive advance of the wheel. The dog 63 is retracted by the same distance the wheel slide is advanced by the infeed means 60 to compensate for dressing of the wheel so that the position of the slide is varied according to the reduction in size of the wheel so that the grinding surface of the wheel always returns to the same position when the slide is returned by the piston 21 and stopping motor 33, the detector 70 reducing the speed as the slide approaches the position.