Patent GB-1007749-A (GB)
Title: Automatic compensating device and automatic compensating and indicating device, for a grinding machine
IPC: B23Q15/00
Filed: 1964-03-16
Abstract: 1,007,749. Grinding. NORTON CO. March 16, 1964 [June 21, 1963], No. 10978/64. Heading B3D. An automatic compensating device in a grinding machine having a trueing device 70 for a grinding wheel 20 and a device 52 for indicating when a workpiece has been reduced to a desired dimension is arranged to be operable in response to the actuation of the trueing device to reset the indicating device to compensate for the reduction in radius of the grinding wheel resulting from each trueing operation. The grinding wheel 20 is rotatably mounted on a slide 12 having a half-nut 24 engaging a lead screw 26 which can be moved axially by a piston-and-cylinder device 28, 30 to rapidly advance the grinding wheel and can be rotated by gearing connected to a hand wheel 38 to manually advance the grinding wheel relative to a workpiece which may be rotatably mounted on a slide movable parallel to the axis of the grinding wheel. A transmitter T1 is connected by gearing to the lead screw 26 so that rotation thereof by the hand wheel 38 causes pulses to be transmitted to a selector 58 connected to a counter 61 which, in turn, is connected to the indicating device 52, the latter having a number of counting discs 59 having numbers which can be viewed through holes 57 in a cover 54; alternatively, the indicating device may be of the type having electronic counting tubes coupled to digital indicating tubes. The trueing device comprises a diamond point 74 mounted in a spindle 72 axially movable by rotation of a screw 78 having a ratchet 80 engaged by a pawl 82 on the rod 84 of a piston- and-cylinder device 86, 88, the stroke of which is adjustable by a screw stop 89. The spindle is supported in a sleeve on a slide 76 which is movable by a piston-and-cylinder device 92, 94 to traverse the diamond point 74 across the grinding wheel. A transmitter T2 is mounted on the slide and connected by gearing 99, 100 to the screw 78 so that rotation thereof by the pawl-and-ratchet causes the transmitter T2 to generate pulses which are fed into the selector 68 which includes an anti-coincidence circuit and algebraically adds the pulses from both transmitters for feeding to the counter 61 and indicating device, the pulses from the transmitter T2 adjusting the device 52 to compensate for the reduction in size of the grinding wheel as a result of the trueing operation. The piston-and-cylinder devices 86, 88 and 92, 94 are connected to a valve V2 controlled by a relay-controlled solenoid S1 the circuit to the device 92, 94 included a valve V3 to ensure that the device 86, 88 is operated first to advance the diamond before the device 92, 94 is operated to traverse the diamond. A limit switch 251 is actuated at the end of the stroke of the device 92, 94 to operate the relay and solenoid S1 so that the devices are returned to their initial position. In other embodiments, the work support is advanced towards a grinding wheel fixed to the base of the machine, the grinding wheel is fed towards the workpiece at an angle to the axis of rotation of the workpiece, or the grinding machine is of the surface grinding type in which the grinding wheel is mounted on a vertical column for movement towards a workpiece secured to a flat table.