| 摘要 |
<p>657,861. Punching and shearing. FAIRWEATHER, W. C. (Naamlooze Vennootschap Betonfabriek de Meteoor). March 16, 1949, No. 7158. [Classes 83 (ii) and 83 (iv)] In a method of simultaneously punching and bending dovetail or like wide-topped lugs 4 in sheet-metal 1, bending cutters 7 with a crosssectional shape corresponding to that of the lugs co-operate with a die 8 having similarlyshaped cavities 9, one or both sides 9a of which diverge and have grooves 10 to permit the lug to be withdrawn. A hold-down 6a may be provided. The sheet 1 may have flanges 2 with inwardly-bent lugs 3 and is stated to be suitable for facing a tile of concrete or the like. One side of each lug may be perpendicular to its base.</p> |
