| 摘要 |
A method of making a beam having a lambda-shaped cross section from a flat sheet of metal. The longitudinal side edges of the metal sheet are initially bent to provide a generally U-shaped section composed of a flat central web and a pair of side flanges that extend at obtuse angles from the web and are joined to the web at bends. The flat central web is then bent at locations spaced inwardly of the first bends to provide a generally flat base and a pair of side sections that are joined to the base at right angle radiused corners and the outer extremities of the side sections are joined to the respective flanges at the first bends. Each side section is then bent inwardly about the corresponding corner to form the lambda configuration in which the side members are at an acute angle to the longitudinal axis of the beam and the side flanges are in proximate flatwise relation.
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