| 摘要 |
<p>The elongated shaped-section units are for use in light-metal ladder or light-metal handrail bars, of a double-T shape in cross-section. The double-T profile unit is provided with corrugated protuberances (10) all round. These are formed by an extrusion process. Protuberances are opposite other protuberances, and depressions opposite other depressions (11) on the main bar, as well as on the flanges (12, 13). The top and bottom flanges (13) may have outer end thickened sections (12). The cross-rungs and hles for fitting may be triangular in section. Rigidity and load bearing capacity are enhanced, without any increase in weight.</p> |
