| 摘要 |
A method for the manufacture of shaped parts of elongate shape and having a variable cross-section from a strip of flat sheet metal. The method is characterised in that the strip of sheet metal is displaced along a generatrix of a shaping mandrel whose cross-section varies progressively along this generatrix in predetermined manner by decreasing dimensions, and in that the strip of sheet metal, as it is displaced, is progressively bent around the shaping mandrel on either side of said generatrix by appropriate pressure means which constrain it to follow the contour and dimensions at the point where their action is exerted, and in that the point of action of said pressure means is displaced along the spindle according to any appropriate law for producing a desired variation of section on the shaped part thus obtained. Such shaped parts may be the masts of pleasure-boats, or support poles for the installation of external lighting.
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