Patent GB-1316635-A (GB)
Title: Grinding machines
IPC: B24B49/04
Filed: 1970-06-09
Abstract: 1316635 Grinding LITTON INDUSTRIES Inc 9 June 1970 [10 June 1969] 27735/70 Heading B3D [Also in Division G1] A grinding machine comprises a bed 11, a work support 12 on the bed having means 13, 14 for supporting a workpiece W, a support for a grinding wheel 17, means for effecting relative transverse movement of the supports to cause grinding infeed, a gauge mechanism 20 positionable to engage an unground portion of a workpiece and including means for generating an electrical size signal indication of an acceptable unground dimension of a workpiece, and electric circuit means for initiating the relative movement only upon receipt of said electrical size signal. The workpiece W has portions A ... E of different diameters and is mounted between a headstock 13 and tailstock 14 on a support 12 movable along the bed 11 by a hand wheel 15 or under the control of a punch card, a transducer 18 providing a signal when a portion of the workpiece to be ground is aligned with the grinding wheel 17 and gauge mechanism 20. The gauge mechanism is mounted on a base member 21 secured to a table 22 slidable on a slide 23 on a sub-base 24 adjustable to the maximum diameter to be ground. An arm 27 is mounted on a pivot 28 on the base member 21, and a further arm 33 is also secured to the pivot and is rockable by a piston-and-cylinder device 30, 31 to move the arm 27 between the phantom and solid positions shown in Fig. 3. The end of the arm is connected by a pair of links 35, 36 of differing lengths to an upper swivel plate 64 associated with a lower swivel plate 63. Leaf springs 42, 43 are secured to the lower swivel plate and to support members 44 having alignment rods 46 connected to lugs 48 on the sides of a transducer housing 40 bolted to a chordaltype caliper 26. The face of the gauge has shoes 80 ... 83 at its outer edges and centre shoes 84, 85 which project slightly more than the outer shoes; the outer shoes are used for checking the longitudinal position of the workpiece by contacting the shoulder of a larger diameter portion of the workpiece and the centre shoes position a probe of the transducer. Irrespective of the size of the workpiece, the probe is always aligned with or near the diameter because of the unequal lengths of the links 35, 36. The shoes contact the workpiece at an angle of 106‹ 15' 36" to provide an 8 : 1 amplification of the probe 86. In operation, with a workpiece in the machine, the carriage 12 is automatically moved to position portion A in alignment with the grinding wheel and the gauge mechanism is moved by actuation of a piston-and-cylinder device (51, 52, Fig. 6, not shown) moving the slide 23 to position the gauge in alignment with the side of the grinding wheel adjacent the shoulder of a larger diameter portion of the workpiece. Fluid pressure is directed to the cylinder 31 so that the arms 33, 37 are rocked to position the gauge adjacent the workpiece, and then to a cylinder 38 having a rod 37 connected to link 35 whereby the calipers engage the workpiece and the probe determines whether the unground portion is within a selected size range. The signal from the probe is fed together with a signal from the punch card to a summing network. If the portion is outside the range, the wheelhead is prevented from advancing. If it is within the range, the wheelhead is advanced towards the workpiece, the piston and cylinder device (51, 52) activated to move the caliper from the shoulder of the workpiece, and the caliper retracted from the workpiece. During grinding, the caliper is engaged with the workpiece so that the probe sends a continuous signal indicating the size of the workpiece. When the signal indicates that the workpiece is nearly to finish size, a signal stops the infeed to allow for spark out until the finish size is reached. The operation is repeated for each of the portions A to E.