GB906969A - Improvements relating to grinding machines - Google Patents

Abstract

906,969. Grinding-machines. CHURCHILL MACHINE TOOL CO. Ltd. July 12, 1961 [July 6, 1960], No. 23585/60. Class 60. A machine for grinding the base and end-face of a workpiece comprises automatic means for bringing the face grinding means, carried on hydraulically-operated slides into the operative position, effecting the face grinding and retracting the grinding means, means for initiating internal grinding, and automatic means for trueing the face grinder whilst grinding the bore. The work a, Fig. 4, is carried in a chuck b and an internal grinder c is mounted on a cross-slide to which a diminishing rate of feed is applied by known means. A face-grinder e is driven by a spindle d carried by an upper cross-slide 1 moved by an hydraulic cylinder 2. The slide 1 is mounted on slide 3 movable on a base 4 in a direction parallel to the axis of the spindle d by an hydraulic cylinder 5. The trueing diamond f is carried by a further crossslide 14, set at an angle to the face of the wheel, which is traversable by an hydraulic cylinder 15. The lower portion 36 of the slide 14 is mounted on a slide 34, 37 movable under spring pressure towards the work a and away from the face-grinder e. The operating cycle is as follows. A solenoid 6 is energized by a starting switch to operate a valve 7 to move the actuator 2 of the crossslide 1 to bring the spindle d coincident with the axis of the work, when a switch 8 is closed by a dog 9, Fig. 1, to energize a solenoid 26 to open a valve 10, whereby the actuator 5 of the slide 3 moves the slide rapidly towards the workpiece until it is slowed by a dog 16 contacting a lever 17 operating a speed-control valve 18. A feed-stop 19 is then in contact with the spring- loaded follower 20 of a cam 21 on the slide 3 which is then stopped with the face-grinder e clear of the workpiece. The inward movement of the follower 20 closes a switch 22 in the circuit of a feed motor 23 which rotates the cam 21 allowing the follower to move further towards the cam centre and, as the hydraulic cylinder 5 is still under pressure, the slide 3 and the grinding wheel e move towards the work until grinding is effected and the face is ground to a pre-set size on the completion of one revolution of the cam when switches 24, 25 are opened to stop the feed motor and de-energize the solenoid 26, whereby the valve 10 controls the return movement of the slide 3 and the spindle d is brought to its rest position. A dog 27 then moves a switch 28 to de-energize the solenoid 6 to allow the slide 1 to traverse to its rest position, when a dog 29 on the slide closes a switch 30 to start the bore grinding operation and also to re-energize the solenoid 26 controlling the forward movement of the slide 3. The speed control valve 18 is operated age in as above described and the stop 19 depresses the cam follower, but as the stop 19 is withdrawn by a pre-set amount by a compensating mechanism 33 the feed motor is not started until the slide has travelled this further distance. As the cam follower 20 approaches the stop 19, stops 35, 36, Fig. 1, come into contact thus holding the slide 34, 37 so that it comes to rest with the face of the grinding wheel e against the trueing diamond f. The cam follower 20 then operates, through a switch 38 a control valve to actuate the dressing-tool traversing slide cylinder 15 so that the tool f moves across the face of the wheel whilst boring is in progress.