Patent GB-356185-A (GB)
Title: Improvements in or relating to screw-cutting die-heads
IPC: B23G5/12
Filed: 1930-04-02
Abstract: 356,185. Screwing die-heads. JONES & LAMSON MACHINE CO., Springfield, Vermont, U.S.A.- (Assignees of Bysshe, E. T. ; 91, Summer Street, and Finn, R. R. ; 98, Wall Street, both in Springfield, Vermont, U.S.A.) April 2, 1930, No. 10512. Convention date, April 3, 1929. [Class 83 (iii).] In a screw-cutting die-head the chasers are positively moved radially to and from the axis by a member movable axially on the head, means being provided tending to move the member to the open position and a latch preventing the opening by engaging said member at a number of angularly spaced positions. Means are also provided for releasing the latch at all of said positions simultaneously. The tangential chasers 10, Fig. 1, are mounted in carriers 6 radially adjustable in dovetailed grooves in the body 3, the carriers being moved by bevelled extensions 52, Fig. 2, of rectangular section carried by a ring 50, and co-acting with bevelled slots 55 in the carriers. Rotation of the ring 50 on the body is prevented by the extensions 52 passing through slots 54 in the body and it is maintained in the advanced position shown in Fig. 2, thereby holding the chasers in the cutting position, by means of a rotatable latch ring 71 having radial projections 70, Figs. 2 and 6, which pass behind corresponding projections 65 on the ring 50. Cam surfaces 80 on the projections 70 are engaged by cams 81 on a ring 85, which, when slid rearwards, rotates the ring 71 and allows axially arranged springs to push the ring 50 rearwards, the projections 65 then passing through openings in the ring 71 between the projections 70. An outer sleeve 95, grooved at 96 for engagement with a yoke, is rigidly attached to the ring 85 and the ring 71 is kept in place by a ring 75 keyed to the body 3 at 111 and secured by a nut 76 screwed at 77 to the body and locked by a screw 115. The ring 85 is slidably keyed to the ring 75 and its rearward motion is limited by a flange 86 on the adjustable nut 76. In operation, with the carriers 6 in the cutting positions and the actuating ring 50 secured in its forward position by the projections 70, the die-head is advanced on the work and when the desired length of thread has been cut further motion of the sleeve 95 is arrested by the usual releasing yoke, whereupon the cam surfaces 80 on the releasing ring 71 ride along the cams 81 on the ring 85 and rotate the ring 71 so as to disengage the projections 70 from the projections 65. When disengaged, the axial springs rapidly retract the ring 50 and positively open the head. To re-set the head the sleeve 95 is moved forwardly causing an annular shoulder 98 thereon to push the ring 50 into the closing position, whereupon a spring plunger 100, Fig. 6, rotates the ring 71 to cause the projections 70 to look the head in the closed condition. In an alternative opening means the flange 157, Fig. 19, on the sleeve 95 is attached by fingers 155 to a rod 154 passing through a slot 153 in the shank 2 of the head and secured to a central plunger 152. An adjustable stop 151 on the plunger is adapted to be engaged by the end of the work 150 when the desired length has been screwed to prevent further movement of the sleeve 95 and open the head. In a futher alternative the plunger 152 is hollow to receive the screwed work and its end is adapted to engage a shoulder on the work. In another modification the sleeve 95 and ring 85 are replaced by a sleeve 170, Fig. 22, keyed to the sleeve 75. The rotatable locking ring 71 carries a cam surface 173 which is engaged by a cam 176, pivoted at 175 to the sleeve, when a projecting portion 177 thereon encounters a fixed stop on the machine, thus rotating the ring 71 to the releasing position. Chasers.-A tangential chaser for use in the die-head is shown in Fig. 18.