GB821681A - Improvements relating to the shaping of metal parts - Google Patents

Abstract

821,681. Angular bending; curving; forging. ELECTRIC & MUSICAL INDUSTRIES Ltd. Dec. 7, 1955 [Sept. 10, 1954], No. 26216/54. Class 83 (4). [Also in Group XXXVIII] Means for deforming a hot or cold metal workpiece B, such as a ship's frame or a bar or strip, to a predetermined pattern comprises means such as bending or forming rollers SR 1 , SR 2 servo-controlled in response to the output of an interpolating device I 1 , I 2 responsive to instructions relating to discrete points or dimensions on the pattern. An angle bar B is drawn by pairs of rollers R 1 , R 2 from a furnace F and passed to rollers SR 1 , SR 2 controlled by hydraulic servo means S 1 , S 2 . One roller of each pair is grooved to receive the bar. The formed bar is then conveyed on rollers CR freely rotatable about horizontal axes and having their shafts journalled in cradles (not shown). The cradles are rotated about vertical axes by gears CG under the control of an electric or hydraulic servo-mechanism H and an interpolator I 3 so that the bar is transported in the direction of movement of its instantaneous centre of gravity. Alternatively, the rollers are journalled in fixed parallel cradles on a platform which is mounted on a circular railway and servo-controlled. The instructions for the quadratic interpolators I 1 -I 3 (such as are described in Specification 796,994, [Group XXXVI], are obtained from binary code punched tapes or films through storage units and switching circuits such as are described in Specifications 796,995 and 807,643, [both in Group XXXVIII]. The controls for the servo-mechanisms include A.C. potentiometer means D 1 -D 3 for producing error signals and may be arranged as in Specification 797,504. The instructions for the tapes PT 1 , PT 2 to produce a bar curved as in Fig. 2a, are obtained by drawing tangents of length 2K from points spaced at intervals s along the curve. The perpendicular lengths m 1 , m 2 , m 3 - and n 1 , n 2 , n 3 - are recorded on the tapes. The instructions for the tape PT 3 are in the form of the magnitudes of the angle #r, Fig. 2b, which is the angle between the initial direction of the bar and the angle that the line from the instantaneous centre Gr makes therewith. In a modification, the bar is formed between rollers R 1 , R 2 , SR, Fig. 3, which are mounted on a table rotated about a pivot under the centre of the bar at R 1 . The roller SR and the table are controlled by servo-mechanisms S, L so that the bar always leaves the furnace in an axial path. In shaping ship-building parts, the parts may be marked according to instructions on the tapes so that the process of flexing battens may be eliminated. Set irons for ship-building may also be produced and the scrive board curve modified so that there is no need to recalculate off-sets. For welded vessels, flat frames of graduated depth may be produced. In a modification, an angle bar is bent and flattened by rollers as shown in Fig. 4, the flattening being done at the same time as, or separately from, the bending. In a forging press, a manipulator M, Fig. 5, controls the movement of a workpiece B in the direction Q and may also control it in angular and crosswise movements and a power hammer PH is controlled in force and movement to produce the dimensions D. The manipulator may be hand-controlled to pick up a billet and then clamped hydraulically before being subject to automatic control. Work can be interrupted for reheating and the process picked up again on the record; meanwhile another billet may be formed by switching over to another record or another reader. The reading units, storage units and interpolators may be mounted on a transportable manipulator or installed in a control room. In a machine for shaping ships' plates, the plate FP, Fig. 6a, is fed between pairs of rolls R controlled through rams TR, BR by servo-mechanism operating in response to interpolation in two directions in a manner analogous to that described in Specification 818,171. The rams are driven by servomotors S and screw-and-nut means U, V, and are coupled by rack-and-pinion means W, X to position analogue units PU. The pairs of rolls are positioned in lines of three, the rolls of each pair being hydraulically connected for pressure equalization.. The rate of feed of the furnaced plate FP is controlled by hydraulic motors which rotate the rolls R. The rams may be rotated by gearing and displacements transverse to the plate may also be controlled by interpolating means, the points of contact of the rolls with the plates following serpentine paths. In a modification of the machine of Fig. 6a, three groups of rolls are spaced across a sheet, each group being arranged as are the rolls in Fig. 3. The centre roll of the centre group is stationary to form a reference point. Pairs of plates of opposite hand may be produced and allowance made for stress relieving and alteration of dimensions on cooling. A workpiece may be produced on a reduced or enlarged scale in a cheap material for checking the record before it is used for production. The invention may be applied to the shaping of railway track sections complete with bolt holes and to the production of bars and sheets of various shapes and dimensions.