GB668011A - Mill for reducing metal stock - Google Patents

Abstract

668,011. Rolling. TUBE REDUCING CORPORATION. March 31, 1950, No. 8127/50. Class 83 (iv). [Also in Group XXIX] A mill for reducing metal stock comprises a reciprocating carriage carrying the reducing rolls, means for reciprocating the carriage, mechanism for feeding the stock to the rolls and turning the stock about its axis, a fluid system for operating the stock feeding and turning mechanisms characterized by a fluid reservoir, a fluid operated motor operatively connected to a hydraulic ram of the stockfeeding mechanism, a second fluid motor operatively connected to the hydraulic ram of the stock turning mechanism check valves being incorporated in the return pipes connecting the reservoir to the ram cylinders and means to time the actuation of the plungers of the rams relative to each other and to the reciprocation of the carriage. Rolls.-A pair of oscillating die rolls 20 are mounted in a reciprocating carriage 21 and are geared together by gears 22 (Figs. 11 and 14), a pair of gears 23 rigidly connected to the gears of one of the pairs .22 mesh with racks 24 to oscillate the rolls 20. The carriage 21 is supported on tracks 25 by rollers 26 fixed to gears 28 which mesh with racks 29 and so prevent the rollers slipping on their tracks. The die rolls 20 have co-operating tapered grooves 21<1>. The carriage is reciprocated by an electric motor 30 which is connected to a crank 35 on a shaft 34 and a connecting rod 36 connects the crank 35 to a rock arm 37 fulcrumed on the mill frame. The other end of the rock arm is forked and each fork is connected to the carriage 21 by links 39. Feed mechanism and mandrel carriage.-The stock S which may be tubular or solid is gripped at its rear end by a chuck 41 rotatable in a longitudinally movable head 42 which is engaged by the forward end of a longitudinally movable but non-rotatable threaded shaft 43 housed in a casing 44. Threaded to this shaft is a feed nut 45 rotatably mounted in a stationary bracket 46 fixed to the mill frame and driven by a fluid motor 112. When the stock is tubular a mandrel M is used and its rear end is held in a block 48 secured to a slidable carriage 49 which while the stock is being fed forward along the mandrel to the die-rolls is rigidly held by latch-slides 49<1>. The stock and the mandrel are rotated approximately through 90 degrees when the die-roll carriage is stationary prior to the beginning of its working stroke. This intermittent turning movement is effected by means of a shaft 50 and its extension 51 through gears 55, 56 and 57 to rotate the mandrel and through gears 59, 60 and 61 to rotate the chuck 41. When the rear end of the stock approaches the die-rolls it is released from the jaws 62 of the chuck 41 by turning a hand wheel 63 and the feed nut 45 is reversed so that the feed shaft 43 and its attached head 42 is returned to its starting position. The hydraulically operated latch slides 49<1> are withdrawn so that the mandrel may also be retracted by means of an auxiliary motor 115 which drives the mandrel carriage 49 by chain and sprockets. A support 72 freely movable along a track 73 sustains the mandrel in its rearward position. The new stock is introduced into the mill so that it abuts against the rear of the previous stock which is gripped by a second rotatable chuck 77 forward of the reducing rolls and which is rotated similarly to chuck 41. When the mandrel has been restored and locked in its operative position the rolling may continue. The second chuck 77 has a sleeve 80 and a collar 81 through both of which the previous stock S<1> passes, jaws 79 being retained between the sleeve and collar within a wedge-ring 82. A gear 78 is slidably keyed to the sleeve 80 so that the grip of the jaws can be relaxed by sliding the sleeve 80 through the gear 78. This is effected hydraulically through a piston in cylinder 83 connected via a lever 86 to a clevis 87 attached to the sleeve 80. The operation of stock and mandrel turning mechanism and the stock feeding mechanism is effected by fluid motors synchronized with the dierolls by means of a cam 90 on a shaft 34 driven from the electric motor 30 (see Group XXIX).