GB569773A - Improved method and means for forming substantially right angle flanges on blanks ofsheet material by pressing - Google Patents

Abstract

569,773. Flanging. TURNBULL, J. S., and METROPOLITAN - VICKERS ELECTRICAL CO., Ltd. Nov. 17, 1943, No. 19199. [Class 83 (iv)] In flanging, by stamping, the edges of sheet material such as aluminium alloy, at least one edge being curved the blank is supported initially between frames resiliently supported so that during flanging by means of a rubber bolster the sheet is dragged from between the frames, and pressed on a former, the frames acting as draw rings. When the flanges are to be at right angles to the sheet the edges of the former are somewhat undercut to compensate for the resilient spring- back. The former 5, Fig. 2, has its edges undercut as shown at 5a and is integral with or supported by a base block 6 itself supported by a supplementary plate 7 on the press plate 8. The sheet 1 is located between lower and upper frames 2, 3 dowelled together at 4 and supported by rubber blocks or helical springs 2a located in holes in the plate 7. Fig. 3 shows. the action of the rubber bolster 9 on completion of the operation and Fig. 4B shows the flange 10a sprung away from the surfaces 5a on release from the press. The plate 7 is provided with numerous holes 7a, those not wanted for the springs 2a, or for the reception of guide pins 11 on the lower frame 2, being closed by covers 7b drilled and tapped for screwpins 6a by which the block 6 may be located. The former 5 may be mounted by lugs 5b received in recesses 2b in the lower frame 2 and it is provided with holes for location of the blank 1 by means of headed pins 1x. The parts 7, 5 and 3 may be made of resinated fabric, and the top surface of the frame 3 is rounded to reduce the wear on the rubber bolster. The opening in the frame 3 is slightly larger than that in the frame 2 so that on upstroke of the press the edge of the opening in the frame 2 may engage the flange on the work and enable the springs 2a to strip the work and frictionally hold frame 5 for separation outside the press. Where the flange is required to be at an angle somewhat greater than a rigHt angle the upper frame 3 is divided longitudinally to permit separation so that the expanded flange may pass through ; to permit this the dowel pins engage holes in rubber inset bushes. To prevent a tendency to buckle, the surface of the base block 6 is slightly dished. The formation of a crescentshaped blank with flanges on its inner and outer curves is illustrated. Reversible parts arranged for producing components of opposite hand are described.