| 摘要 |
A method is disclosed for fabricating a hollow bar (10) that forms elements of a grille or railing of a metalwork piece where the bar is twisted manually, machine-assisted or automated machinery, into a spiral form for decorative or ornamental purposes. By providing the hollow bar (10) to be comprised of separate longitudinal parts (200, 202) which may be hinged-joined to complementarily fastened to each other to form the hollow bar (10), the longitudinal joint means (204, 206) are thus amenable to increased torsional stress, such that each of the parts (200, 202) may be twisted without breaching the material's fatigue limit and the bar (10) as a whole capable of being twisted with more spiral turns within its elasticity limits. The twisted bar may thus be released for re-working for adjustments or re-installation. A number of exemplary joint embodiments, internal and external bracing accessories are also disclosed to cater for the different longitudinal part fabrication, e.g. by extrusion or roll-milling.
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