Patent GB-936325-A (GB)
Title: Improvements in or relating to method for positioning a workpiece in a machine
Inventor: BASSO JOSEPH CHARLES
IPC: B24B41/06
Filed: 1962-03-12
Abstract: 936,325. Lathe centres. DE LAVAL STEAM TURBINE CO. March 12, 1962, No. 9487/62. Class 83 (3). [Also in Group XXIII] A method of positioning work in a lathe, grinding machine &c., comprises the steps of aligning the male centres at the head and tail ends of the machine at a close position, retracting the tail centre to a work-receiving position, adjusting the retracted tail centre to re-align the centres, placing female centres at the ends of the work, at least one of the female centres being adjustable, mounting the work on the male centres by means of the female centres, and aligning the female centres by adjustment of the adjustable female centre. The adjustable female centres, Fig. 3, for securing to the work by taper pins and screws passing through holes 16, 18, comprise a base 10 on which a pointreceiving part 24 is adjustable laterally by four or eight wedges 50 operated by screws 44. Four spiral oil-grooves, Fig. 10 (not shown), are provided in the conical surface 34 of the centre. A non-adjustable male centre 74 is used in the headstock, and in the tailstock 64, Fig. 4, a male centre 60 is used which has similar wedgeadjustment to that of the female centre. With the headstock and tailstock close together, Fig. 5 (not shown), a clock-gauge mounted on the headstock-centre is used to check for misalignment which is corrected by adjustment of the wedges surrounding the point of the adjustable centre 60. A bracket 96, Fig. 1B, carrying an optical target 110 is fixed to the headstock-centre 74, and a bracket 98 supporting pivotally a telescope 108 is fixed to the centre 60, the bracket being aligned with a reference bar, Fig. 8 (not shown), fixed to the base of centre 60. After alignment of the brackets, the telescope is sighted on the target and its verniers set to zero. The tailstock is then retracted, Fig. 1C, and any misalignment in the retracted position between the sight-line 118 and the target-axis 120 is corrected by adjustment of the centre 60. For short workpieces, a non-adjustable centre may be used in the tailstock, which is aligned with the head stock-centre by scraping the bed of the tailstock. An adjustable female centre 122, 124, Fig. 9, may be fixed to each end of the work and squared by scraping the shoulders 26, 28, Fig. 3, in accordance with readings from an electronic indicator (not shown) including a gauge-head. The female centres 122, 124 are aligned, by adjustment of the wedges surrounding their centre parts 132, 134, in accordance with gauges 136, 138 carried by the centres 60, 74 and bearing on the parts 132, 134, the gauges being connected to an electronic indicator 142, which may be connected to means for making a polar chart of the gauge readings. If the aligned female centres 132, 134 are not central of the work 126, this will be shown on the indicator 142 by gauges 150 carried by racks 154 and bearing on the work. The centres 132, 134 can be adjusted towards the work-centre by by their surrounding wedges, and the centre assembly 122 may attach a ring 130 to the work for engagement by a driver 131.