| 摘要 |
Apparatus and method for making at least two metal bands into a hollow rail, e.g. for door and window frames, wherein the bands are simultaneously drawn by a tractive force acting from the formed end, e.g. by a power-operated reciprocal clamp, through non-driven roll-type forming tools which shape the bands into profiles while under the tractive force so that the bands are strengthened and straightened in at least some longitudinal zones. While being drawn through the forming tools a non-metallic elastic shim liner is fed and applied to the edges of at least one of the bands and after both bands have been profiled, they are pressed together, by appropriate guiding and shaping tools, whereby the longitudinal edges of the bands are connected together by a folded welt that completely encloses the shim liner while the latter prevents friction metallic contact between the two bands. |
