GB479076A - Improvements in and relating to turning lathes for copying - Google Patents

Abstract

479,076. Copying-lathes. ATELIERS, G. S. P. Dec. 14, 1936, Nos. 34326, 34327, and 34328. Convention dates, Jan. 22, March 9, and April 7. [Class 83 (iii)] In a turning - lathe for copying, particularly for use in making the metal blades of airscrews, of the kind in which the pattern and work rotate about parallel axes and opposed tracer rollers and milling - cutters act simultaneously on opposite sides of the pattern and work respectively, the supports for the tracers are joumalled about a pivot different from but parallel to the pivot of the cutter supports and connected thereto by a link. The pattern 1 and work 5 are rotated about parallel axes 2, 4 and the tracer rollers 16, 17 are rotatably mounted on arms 8, 9 pivoted at 6 on a table 28 which is traversed automatically or by hand parallel to the axes 2, 4. The rotating cutters 20, 21 are carried by arms 10, 11 pivoted on the table at 7 and connected by links 22, 23 to the arms 8, 9, weights 18, 19 serving to maintain the tracers in contact with the pattern. Additional pairs of arms 10, 11 may be provided for carrying cutters acting on further work pieces so that, e.g. the blades of a three-bladed propeller may be produced simultaneously. The effective lengths of the links 22, 23 may be adjusted, to compensate for differences in the diameters of the cutters due to grinding &c., by adjusting the pivots 24, 27 relatively thereto through screws. The pattern and work are driven simultaneously at both ends from a shaft 39, Fig. 3, through gears 40-49, the gears 40, 41, 46, 47 being formed in two angularly adjustable parts in order to eliminate back-lash. The work and pattern are held at one end by sockets 51 on spindles 50 supported in bushes 53 by means of ball ends 501 and driving pins 52, and at the other end by axially slidable bushes 54, 55 and a spindle 56 engaging the work &c. through a screw-thread so that rotation of the spindle 56 by a wrench &c. will impart tension to the work and pattern to assist in preventing flexure thereof during operation. The axial forces are absorbed by ball thrust bearings 58, 59. In a modified support the work and pattern are secured to carriers 54, Fig. 4, centred in the driving spindles 70 by pins 71 and rotated by dogs 72. Axial tension is applied to the spindles 70 through screws and nuts 56, and thence to the work &c. through links 61 having the effect of Cardan joints so that the tension will act along a line G tangential to the curve passing through the centres of gravity of the adjacent sections of the blade. The tension is transmitted to the spindles 70 from the screws 56 through springs 60.