Patent GB-431288-A (GB)
Title: Improvements in or relating to grinding machines
IPC: B24B5/35
Filed: 1934-04-13
Abstract: 431,288. Grinding. HEALD MACHINE CO., 10, New Bond Street, Worcester, Massachusetts, U.S.A.-(Assignees of Blood, H. L., and Burns, A. P.) April 13, 1934, No. 11188. Convention date, Aug. 8, 1933. [Class 60] In a machine for grinding the internal surfaces of sleeves, bushings, &c., the work-piece is mounted upon a reciprocating table 1 and is ground by a grinding- wheel 6 supported and driven by a head mounted on a bridge. The wheel 6 may be fed by mechanism including means for compensating for wear and dressing of the wheel, and the table 1 is reciprocated by fluid pressure means and reversed by means of dogs and reversing-mechanism. The workpiece a is mounted and driven in a centreless work supporting structure in a head 2 comprising a regulating-wheel 206 carried by a hollow spindle 205 driven by worm gearing from a motor 219 and a work supporting wheel 207 carried by an adjustable slide 208. The work is held against the wheels 206, 207 by a pressure wheel 213 on a shaft 213<1> in the end of an arm 214 carried by a shaft 215, and the axis of the roller is slightly inclined to urge the work against a rotatable backing plate 222 carried by the head 2. The grinding operation is under the control of two gauge members 223, 224 carried on a rod 225 passing through the plate 222 and carrying an arm 227 moved by a spring-pressed rod 230 to urge the gauges up to the work. The arm 227 also carries, in an arm 237, a screw 238 which, when the gauge 223 enters the work causes the table 1 to move on an extended stroke for trueing the wheel 6, and when the gauge 224 enters the work, to stop the grinding and move the table to carry the work away from the grinder. During this latter movement of the table to the rest position, the workpiece is ejected from its supporting means by an ejector arm 345, 346 adjustably mounted on a shaft 344 journalled in the spindle 205 and rotated through gearing 350, 351 by a cam 356 on the machine base, which engages a roller 355 on an arm 354 carried by the shaft 352 of the gear 351. The pressure wheel 213 is simultaneously lifted, to allow ejection of the work, by means of a U-shaped member 366, 367 secured on the shaft 215 and carrying adjusting screws 370, 371 engaging the arm 365 of a bell-crank lever rotatable on the shaft 215 by a lever 361, which is moved by a cam 358 on the shaft 344 ; a spring 372 resiliently and adjustably presses the lever 365 to press the wheel 213 against the work. Workpieces a are supplied to the supporting device from a bracket 376, adjustably mounted on a part 375 on the table 1 and having therein a sloping groove containing the workpieces which are held in the groove by an arm 383 carried by a shaft 384 rotatable in a bracket 3811, the arm 383 being lifted, to allow a workpiece to fall from the groove on to the ejector arm 346, by a plunger 386 acting on an arm 385 on the shaft 384 and lifted by a cam 388 on the shaft 344; as the ejector arm 346 returns to its normal position upon the movement of the work-table into operative position, the workpiece follows the arm, and moves along a groove 382 in the bracket 376 to the work supporting device. Finished workpieces, lifted by the ejector, roll on to an inclined surface 393 on the end of an arm 394 pivoted at 395 to the bracket 381<1>, and are there stopped by the forward edge of an inclined surface 397 ; the arm 394 is subsequently lifted by means of a cam surface 401 and a roller 400 on an arm 398 connected with the arm 394 to allow the workpiece to roll down the surface 397. Before ejection of a workpiece the gauges 223, 224 are retracted from the work by means of a piston 335 moved by fluid pressure in a bore 334, against a spring 340, to engage a screw adjustably mounted in the arm 227. In order to avoid the necessity for manual starting of the machine for each workpiece, the table 1 carries a dog which engages a portion of the reversing member, thereby causing a return movement of the workhead to operative position.