Patent GB-899460-A (GB)
Title: Machine tool workpiece support
IPC: B24B5/35
Filed: 1961-04-13
Abstract: 899,460. Grinding. CINCINNATI MILLING MACHINE CO. April 13, 1961 [June 27, 1960], No. 13301/61. Class 60. A grinding machine has a face plate rotatable about an axis for slidably gripping for rotation one end of a workpiece extending in the axial direction therefrom, a fixed support located adjacent the rotatable face, at least one shoe member being pivotally mounted on said support for swivelling in a plane extending in the axial direction about a pivot point and said shoe member being adopted to engage the periphery of the workpiece and having two axially spaced extreme workpiece engaging contact points on each side of the pivot point in the axial direction. A magnetic driver 6 has an annular face plate 6a slidably engaging an annular flat 7a machined in the rounded end of a truncated conical workpiece 7. The longitudinal axis 7b of the workpiece is eccentric relative to the longitudinal axis of rotation 6b of the driver whereby the workpiece is rotated and urged against a shoe member 27 below the workpiece and a shoe member 49 at the side of the work piece remote from the grinding wheel 65. A bracket has a base 11 secured to the machine bed 14 by bolts 9 extending through slots 8 in side flanges 12, 13 of the base 11 permitting longitudinal adjustment. The bracket has a front wall 15 with side flanges 16, 17. Bolts 21 extending through slots 22 in the wall flanges secure to the front wall a vertically adjustable plate 23 having adjustable feet 24, 25 seating on a shelf 26 on the forward side of the front wall 15. The lower shoe member 27 is pivotally mounted on the plate 23 by a pivot pin 28. Bolts 32 secured in the plate 23 and extending through slots 33 in the shoe member 27 retain the shoe member 27 on the pivot pin 28 but do not clamp the shoe member 27 against the plate 23. The amount of swivel of the shoe member 27 is limited by adjustable feet 29, 30 co-operating with a shelf 31 extending from the lower end of the plate 23. The shoe member 27 has a portion 34 engaging the workpiece along its length including two extreme points of engagement at each end of the workpiece, the pivot axis being between the extreme workpiece-engaging points in the longitudinal direction and spaced from the workpiece periphery. Extending rearwardly from the front wall 15 of the bracket are spaced webs 19, 20 between which is received a block 40 having slots 41 reciving bolts 42 which secure the block in desired adjusted position. A plate 43 is adjustable on the block 40 by a screw 46 and has slots 45 receiving bolts 44 by which it is secured to the block 40. The shoe member 49 is pivotally mounted on the plate 43 by a pivot pin 48, a nut 50 retaining the shoe member 49 on the pin 48 without clamping it to the plate 43. The workpiece-engaging portion of the shoe member 49 comprises spaced pad members 51, 52 swing- able on pivot pins 53, 54. Each pad member comprises pad portions 55, 56 swingable on pivot pins 57, 58. The axis of the pivot pin 48 is between the pad members 51, 52 in the longitudinal direction and is spaced from the workpiece periphery. If the end of the workpiece engaged by the driver is not square to the axis, the shoes effect shifting of the workpiece relative to the driver so as to prevent rocking of the workpiece. When the advance of the grinding wheel is stopped at a predetermined point the workpiece will be ground to precise size with the longitudinal axis thereof square with the driven end. As the axis of pivots 28, 48 are spaced from the workpiece periphery, there will be a small relative axial movement between the shoes and the workpiece as the shoe members swivel, thus producing a damping force tending to prevent resonance.