Patent GB-974577-A (GB)
Title: Improved machine tool feed system
IPC: B24B51/00
Filed: 1963-05-31
Abstract: 974,577. Grinding; machine tool details. CINCINNATI MILLING MACHINE CO. May 31, 1963 [July 23, 1962], No. 21866/63. Headings B3B and B3D. [Also in Division G4]  A feed system for a grinding machine comprises tool feed means having a feed member 49, Fig. 2, for moving a tool 46 through a feed range, tool adjusting means 102 for moving the tool through an adjusting zone relative to the feed member whereby the feed range is adjusted, and a settable reversible counter arranged to respond to movements of the adjusting means, the counter controlling a read-out unit 97, Fig. 1, whereby the unit indicates the position of the tool relative to the feed member in terms of workpiece size to be produced upon movement of the tool through the adjusted feed range. The tool comprises a grinding wheel 46 mounted on a wheelhead 45 which is movable towards and from a rotating workpiece 21 along guideways 43, the workpiece being mounted between head and tail stocks 19, 20 on a carriage movable along guideways 18 by a hand wheel 22 of a piston-and-cylinder device 24, 25 controlled by a dog 36 engaging stops 37, 38 and a control circuit 35 and pump 28. The pump is also connected by an infeed control circuit 52 to a cylinder 47 having a piston 48 which is connected to the feed member, which is in the form of a screw 49, so as to advance the wheel 46 first at a rapid speed and then at a slow speed. The screw 49 is in screw-threaded engagement with a depending portion 45a of the wheelhead, and is rotated to adjust the position of the wheelhead relative to the screw, which, during plunge grinding, always moves to a position determined by abutment of the piston 48 against an end wall of the cylinder 47. Backlash between the screw 49 and wheelhead 45 is prevented by fluid pressure supplied to a piston and cylinder device 53, 55. The screw 49 is rotated to adjust the wheelhead by a hand wheel 75 connected by gearing to a shaft 60 joined by a splined coupling 62 to the screw 49 to permit relative axial movement therebetween; the gearing is arranged so that rotation of the hand wheel effects a rapid or fine movement of the wheelhead relative to the screw 49. The rotation of the screw 49 is imparted by the shaft 60 and gearing 63 having anti-backlash means to a shaft 105, Fig. 9, of a pulse generator 104 having a slotted disc 109 disposed between a light source 107 and a pair of phototransistors 108A, 108B which produces electrical pulses, the pulse from one phototransistor leading that of the other according to the direction of rotation of the shaft 105 at screw 49. The pulses from the phototransistors are converted from a square to a peaked shape by trigger circuits 113A, 113B, Fig. 7, and a pulse shaping circuit 128A, 128B. Pulses from each phototransistor are fed to AND circuits 127A, 127B from one or other of which pulses are produced depending on the direction of rotation of the screw 49. Each AND circuit is connected to NOR circuits 144A, 144B and pulse pairing circuits 146A, 146B joined by connections 173, 174 to lines 179, 180 of an electronic cold cathode counting tube 175e connected to other counting tubes 175a. . . 175d. Each tube controls one digit 187 of an indicating number 98 on the read-out unit 97 which shows the size a workpiece will be ground to with the grinding wheel in a particular position relative to the screw 49. Setting devices 200a ... 200e provide for adjustment of the tubes and number 98. In operation, the screw 49 is moved to its forward position by operation of the device 47, 48 so that the grinding wheel produces a surface of the workpiece which is then measured. The setting devices 200a ... 200e are then operated to set the counting tubes and number 98 to correspond to the dimension produced. Thereafter, rotation of the screw 49 by the handwheel 75 through the fast and/or slow gearing will cause the disc 109 on shaft 105 to rotate and the pairs of pulses to pass through the circuit to actuate the tubes 175 and number 98 to indicate the size the workpiece will be ground to when the screw 49 and wheel are again advanced to their forward positions. If the wheel is trued and the reduction in size of the grinding wheel is known, the wheelhead can be moved forward relative to the screw 49 by the known distance as indicated by the number 98. During traverse grinding, the hand wheel 75 or a pick feed mechanism rotates the screw of each traverse of the workpiece until the number 98 shown on the readout unit 97 indicates the finished size of the workpiece.