| 摘要 |
1,049,600. Making lattice girders; bending; corrugating; stamping; welding by pressure. J. G. S. KELLER. Nov. 3, 1964 [Nov. 18, 1963], No. 44751/64. Headings B3A, B3E, B3Q and B3R. In a method of automatically producing lattice girders, steel strip is intermittently unwound from reels R 1 , R 2 , passing through rollers 65-57 and 55a-57a for descaling, and are partially shaped in pairs of shaping rollers 7 to 9 and 7a-9a. Strip for the web is unwound from a reel R3, passed through rollers which de-scale, stretch, workharden and roll it (Fig. 8, not shown) and is perforated by a device 26, 27 at intervals equal to the length of a portion 3, 3<SP>1</SP>. The last of the descaling rollers or the guide roller following is flanged to align the edges of the strip. A shaping device comprising mating press tools 28, 29 forms the inclined parts of the web to a U.V.C. or like channel section. The formed strip passes to a folding device (Fig. 7, not shown) in which a stationary clamping element 49 co-operates with a movable clamping device 50 to form a corrugation. The device 50 is mounted on a carriage which has a pivoted arm to give a slight initial upward bend to the strip. Embossing tools 51, 51a form projections on the chord members to which the flat portions of the web are welded by resistance electrodes 14, 14a during pauses in the advance of the workpieces. Rollers 10-12 and 10a-12a form the chord members to their final shape 1f, 2f (Fig. 2, not shown). An advancing device comprising reciprocating grippers engages the completed girder and advances the material step by step, none of the various rollers being driven. |
