GRINDSTONE BED CUTTING CONTROL DEVICE IN GRINDER

PURPOSE:To enhance the reliability of a grinder, by providing such an arrangement that the position of the grinding surface of a grinding wheel after dressing is electrically detected by an absolute position detector, and a grindstone bed may be directly moved to a specific position such as, for example, the original point of working, in accordance with the detected position of the grinding surface. CONSTITUTION:A feed screw 11 adapted to be rotated by a servo-motor 12 is threadedly engaged in a nut 10a attached to the lower surface of a grindstone bed 10 to which a grinding wheel G is journalled. Further, a first absolute position detector 13 for detecting the absolute position of the grindstone bed 10 is secured to the rear end of the serve-motor 12, and issues a retracted amount of the grindstone bed 10 as the information of the absolute position. Meanwhile, a dresser head 15 is supported movably toward the center of the grinding wheel G. Further, a dressing tool D is attached to the front end of the head 15, and is extended and retracted by means of the servo- motor 12. A second absolute position detector 21 for detecting the absolute position of the head 15 is secured to a motor 20. A numerical control device 25 comprises a central processing unit 30, a memory 31 and interfaces 32, 35, 36, and is connected with motor drive units DUX, DUU.