GB147023A - Improvements in screw cutting die-heads - Google Patents

Abstract

147,023. Landis Machine Co., (Assignees of Miller, D. J.). July 22, 1918, [Convention date]'. Screwing die-heads.-A self-opening die-head of the type having cutters pivoted in a plane transverse to the die axis is adapted to take roughing and finishing cuts for either right or left handed threads. The cutter holders B are secured to trunnions 11 in a body part A and their outer ends have slots connected by pivots 14 to a ring 15 rocked by a handle 76 to open and close the die. A ring 16 mounted on the body between the body flange 17 and the ring 15 is bored tangentially to receive a screw 20 engaging a spiral thread on the body. The handle 76 carries a reversible spring pressed latch pin 23 having one of its lower edges nearer the centre than the other, Fig. 1, and engaging notches 68 on a latch pin 29, passing through a slot in the ring 15 and holding the two rings 15, 16 against rotation on the body when the latch is engaged. The body has apertures 50 each containing a tensioned spring 51 one arm 53 of which engages a hole 54 on each cutter holder, and this tends to open the die. The ring 16 is secured to the body flange by bolts 60 the heads of which have a limited end movement as shown at 62. The cutters are first set to the required diameter by means of the screw 20 and when the cutting is nearly completed, a stop on the turret checks the feed and the die being drawn towards the work the rings 16, 17 are separated axially from the body flange, releasing the latch 23. The springs 51 then operate to open the die, whereupon the parts 16, 17 are returned by the spring 61. If a preliminary roughing cut is desired, the latch 23 is turned to the side which gives the die a slightly opened position and then reversed for the finishing cut. For cutting left-hand threads, the latch pin 29 is reversed, the notch 68 then being operative to lock the die for left-hand cutting.