GB1036971A - Improvements in and relating to method and apparatus for roll forming metal articles - Google Patents

Abstract

1,036,971. Spinning; rolling; making hollowware. N.T.W. MISSILE ENGINEERING Inc. May 13, 1963 [May 14, 1962], No. 18799/63. Headings B3A, B3J and B3M. An extrusive rolling method for forming a thin-walled hollow metal article includes the steps of fitting a relatively thick, short blank in a female die, applying a forming roller to the inner wall of the blank, relatively rotating the roller and blank and moving the roller in a path parallel to the cross-sectional contour of the wall of the die to elongate the blank while reducing its wall thickness. A die D carrying a blank is rotated in a turntable A, and a roller forming unit F is adjustably mounted in a head H which can be shifted horizontally relative to a supporting carriage C by means of hydraulically operated piston E. The carriage C is itself movable vertically on a gantry B by means of screw jacks 27. A forming roller 57 (Fig. 4, not shown) is mounted on a shaft 61 in a carriage which runs in guide slots formed by bars 70 and 72 in the head H. Rollers 58 at the four corners of the carriage transmit rolling pressure to the rear guide surfaces 71, while smaller rollers 60 transversely guide the carriage. The carriage is attached by a clevis 107 to the piston-rod of an actuator I which traverses the carriage along the contoured slots. Radial adjustment of the carriage relative to the workpiece axis X is by means of a screw J which is mounted in a bracket 119 attached to the boss 84 of head H. Rotation of the screw shifts a frame 111, to which are attached wedges 110, which co-operate with the guide bars 72, vertically such that the guide bars 72 are moved radially in slots provided in the head H. A screwed rod 85, which is attached to the turntable and passes through a bore in boss 84, locates the head H. The head is supported in bearings 86 and guided by rollers 82 (Fig. 6, not shown) which co-operate with the rim of the die D, and the workpiece W is clamped to the base of the bar by arcuate sections 47 provided with flanges which engage an annular slot 46 in the workpiece. In operation, after the blank has been clamped in position, the head H is lowered into position using the rod 85 as a guide, and the actuator I moves the carriage F to its lowest position. The roller 57 is then moved radially by means of the screws J until a groove of the required depth is formed in the blank. The roller 57 is then raised slowly by the actuator I to thin and extend the blank against the inner wall of the die. A number of such passes can be made until the blank reaches its required dimensions. By appropriate manipulation of the roller 57 internal annular ridges can be formed on a workpiece. In a modification, the roller 57 can be urged towards a carriage which rolls on the contoured outer surface of the die, the roller and carriage being mounted on two arms of an adjustable head. A cup-shaped blank may also be rolled using modified apparatus, and if the workpiece is to be made of hemispherical contour the rolling head itself can be pivotably mounted on an axis perpendicular to the workpieee axis. In all cases the die can be held stationary and the rolling head rotated.