Patent GB-439258-A (GB)
Title: Improvements in apparatus for the manufacture of the grooved rolls as used in pilger-rolling mills
IPC: B23Q35/08
Filed: 1934-08-22
Abstract: 439,258. Making Pilger rolls for tuberolling. STEWARTS & LLOYDS, Ltd., 41, Oswald Street, Glasgow, and DAVIDSON, G., 143, Main Street, Wishaw, Lanarkshire. Aug. 22, 1934, No. 24192. [Classes 83 (iii) and 83 (iv)] In a lathe such as that described in Specification 169,955 for cutting the grooves of Pilger rolls used in tube - rolling mills wherein the tool 1, Fig. 1, is reciprocated transversely of the work axis to impart the eccentric shape to the roll by means of a control cam 3, the cam is driven at a variable speed in order to modify the form of groove produced. In Fig. 1, W, X, Y and Z indicate respectively the " bellmouth " finishing pass, " relief " and " gap " of the roll pass. In order that the working length of the roll may be made of the maximum possible length irrespective of the roll diameter a first correcting motion is imparted to the cam drive whereby a cyclical increase and decrease in the cam speed is imparted during each revolution of the roll. Further, in order to modify the roll profile at the " bellmouth " from the normal profile 7 to that shown in the dotted line in Fig. 3 whereby a more uniform stressing of the material driving rolling is obtained, a second correcting motion is imparted to the cam drive whereby a cyclical increase and decrease in the cam speed is imparted during the time taken by the tool in swinging across the groove from A to B, Fig. 3. This control has no effect during the action of concentric cam parts so that the finishing pass is not affected. These two correcting motions are both obtained by means of epicyclic gearing. The control cam 3 is normally driven from a constant speed spindle 8 but according to the invention the cam is driven from a sleeve 9 enclosing the spindle 8 and secured to a sleeve 9<a> carrying a pinion 11 connected through an upper pinion 15 on a loose disc 12 to an internally toothed ring 17. A lower pinion 14 on the disc 12 engages a pinion 10 on the shaft 8 and an externally toothed disc 16 loose on the sleeve 9<a>. These gears form a double epicyclic gearing whereby if the rings 16, 17 are held stationary the uniform movement of the wheel 10 on the shaft 8 will be transmitted unchanged to the pinion 11 on sleeve 9<a> but the movement of pinion 11 will be modified by rotation of either or both the rings 16, 17. The second correcting movement referred to above for deepening the bellmouth is obtained by rocking the ring 17 by a connecting-rod 19 connected to an adjustable crank disc 18 which is timed to rotate through one revolution while the tool travels from A to B. The first correcting movement for obtaining maximum length of working pass is obtained by oscillation of the ring 16 by a connecting-rod 19<a> connected to a crank disc 22 which makes one revolution for each revolution of the work in the roll. The disc 18 is driven from the shaft 8 through spur gearing 24, 25 and toothed rim 27 bolted to disc 22. The latter carries a number of cam projections 28 which actuate a pivoted lever 30 operating a ratchet wheel 33 connected to the disc 18 by gearing 36-38 and toothed ring 39. The number of cam projections 28 is varied according to whether the pawl controlling the circular feed is set to take 1, 2, or 3 or more teeth of its ratchet wheel at one sweep. In some cases the number of cams 28 may be varied for different parts of the roll travel so that further modifications of the roll profile may be obtained. The flat side portions 6 of the profile are obtained in the manner described in Specification 169,955, [Class 83 (iii)].