GB965759A - Improvements in or relating to machines for working sheet metal - Google Patents

Abstract

965,759. Making roofing sheets; stamping; angular bending. COOKSON SHEET METAL DEVELOPMENTS Ltd. July 28, 1961 [Aug. 8, 1960], No. 27418/60. Headings B3A, B3E and B3Q. A method of shaping an end of a metal sheet having at least one rib upstanding from the plane of the sheet, e.g. sheet metal roofing and siding sheets comprising acting with a forming tool or tools, upon end portions of the sheet at opposite sides of the rib to bend those portions of the sheet out of the plane of the sheet whereby, without the tool or tools acting on the sheet in the region of the rib, that region of the sheet is caused to bend upwardly. Apparatus for carrying out the method comprises an hydraulic press 16 having a horizontal table 32 and a vertically reciprocable ram plate 36 actuated by an hydraulic cylinder 40. A flattening tool 44 carried by rams 46 and 47 is provided with a combined sheering and flanging device 45-a fixed bed plate 52 has three rib inner support tools 54 having chamfered ends 56 which co-operate with cut-outs 42 in the ram plate 36 to clamp the roofing sheet in the press. Positioned in bearings 58 is a wiper tool 60 rotated through a link device 62 (Fig. 2) by a ram 64. Side guides 68 are provided on the table 32 for a support tool 70 actuated by an hydraulic ram 72. Above the support tool 70, the guides also locate a combined spring-loaded shearing and flanging device 76 actuated by an hydraulic ram 78. The rams are controlled from a valve control box 82. Each end of the ram plate 36 is provided with a cam-operated releasable clamping device 84 in conjunction with a trigger clamp 86 positioned on each end of wiper tool 60. On the front of frame 24 are provided two trigger arm devices 88. In operation, as the ram plate 36 descends to clamp the sheet 90 in the press, the cam plate 114 of clamping device 84 swivels the trigger clamp 86 until its end 108 clamps the sheet to the wiper tool 60. Fig. 7. In the first stage of the forming process the wiper tool is rotated upwards to bend the sheet and turn the end 96 of the rib 94 inside out as shown in Figs. 9 and 10. At the limit of travel of the wiper tool a striker 124 on the wiper tool engages the head of a hammer 120 which in turn engages the trigger clamp 86 and returns it to its initial position. The wiper tool is returned to its initial position and the support tool 70 is moved forward to back up the slanting edge 135 of pocket 128 on the sheet 90. As the flattening tool 44 is lowered the trigger arm 140 of the trigger device 88 is forced towards the frame 24 by guide plate 156 on the flattening tool. The tip 158 of the trigger arm which is positioned behind the wall 130 of the pocket 128 thus bends the wall to the required shape, Fig. 12, for the flattening operation, as shown in Figs. 13 and 14. The final shearing and flanging operation, Fig. 16, is effected by the shearing and flanging device 76 which consists of a spring-loaded bending plate 172 carrying a shearing blade 180 which co-operates with a shearing blade 152 and notching blade 154 (Fig. 12) on the flattening tool 44. The final shape of the roofing sheet is shown in Fig. 4.