GB343747A - Metal cutting machine tools - Google Patents

Abstract

343,747. Screwing die-heads. HERBERT, SIR A., Dunley Manor, near Whitchurch, Hampshire, DRANE, H. A., 77, Northfield Road, Stoke, and HARMER, F. S., Colintraive, Stoneleigh Avenue, both in Coventry. Feb. 20, 1930, No. 5674. [Class 83 (iii).] In a device for automatically cutting tapered screw-threads the die-head 2, whose chasers are operated by a rotary cam-plate, is secured by its shank and an adapter 3 to the rotary machine spindle 4. A sleeve 5 mounted on and rotatable with the die-head is provided with a pair of oppositely located slots 6 engaging radial pins 8 on the cam-plate and a pair of similar slots 7 engaging pins 9 on the shank, the slots 6, 7 being relatively inclined so as to cause rotation between the camplate and shank on relative axial movement between the die-head and sleeve. An annular groove 10 in the sleeve is engaged by a yoke 11 slidable on a stationary guide 13 and on a screwed rod 14 carrying adjustable stops 15, 16. In operation, the sleeve 5 advances with the die-head towards the work until the yoke-meets the stop 16 just as the chasers engage the work, whereupon the die-head travels forwards on the work whilst the sleeve remains stationary to rotate the cam-plate relatively to the shank and thereby cause the head to be opened progressively. The slots 6, 7 may be straight or curved according to the shape of the cam-plate, and the sleeve and chasers are readily replaceable to suit different tapers. For the return movement the rotation of the spindle is reversed and the sleeve and die-head are withdrawn together until the yoke meets the stop 15, after which the die-head alone recedes to effect closing.