GB502123A - Improvements in and relating to machines for grinding the relieved threads of screw-cutting hobs and taps - Google Patents

Abstract

502,123. Grinding hobs and taps. TURRETTINI, F. Oct. 29, 1937, No. 29583. [Class 60] A machine for grinding relieved screw threads on taps or hobs comprises a bed 15 on which is slidable a table 16 having thereon a headstock 9 and a tailstock 17 supporting a work-piece 20. On the bed is journalled a shaft 1 driven by a pulley 2, which drives, through gearing 4-7, a shaft 3 carrying two cams 18, 19 ; the shaft also drives, through chain or other gearing, the work-driving spindle 8 from which a lead screw 13 is driven by gearing 11, 12, the screw 13 being carried by the cable 16 and engaging a nut 14 secured to the bed 15. On a rotatable and slidable rod 22 are mounted two rollers 23, 24 so arranged that by turning the rod, either of the rollers may engage the appropriate cam 19 or 18, the other roller being out of action. The rod is connected to a slide 26 on which is pivoted a bar 27 adapted, during axial movements of the rod 22, to actuate a plunger 30 of a hydraulic servo-motor 31, the driven part, 32, of which moves a slide 33, carrying the grinding- wheel.21, towards and from the work; the cam 19 is employed for trueing the wheel 21 by means of a diamond &c. tool 40 carried by the tail centre 34 or by the tailstock, and the cam 18 is employed for grinding relief on the work. The inclination of the bar 27 may be adjusted by a screw 29 to adjust the stroke of the slide 33.