| 摘要 |
The scaffolding board (21) is moulded from a compound, light-hardened, duroplastic material and, in one embodiment, it comprises a box-shaped upper portion (22) provided with grooving (24), a box-shaped intermediate portion (20) provided with longitudinal ribs (30), and a lower, also box-shaped edge trim (28), all three portions being glued together. To produce the individual portions of the scaffolding board, a web of plastics material is clamped onto an air-permeable lower mould portion and filled with compressed-air, and the arched material is simultaneously heated and expanded. Subsequently, the lower mould portion is filled with vacuum, and the heated material is sucked-in and deep-drawn in order to adapt to the shape of the mould interior. Subsequently, the moulded part is exposed to a source of ultra-violet light and hence hardened. Finally, compressed-air is introduced in order to lift-out the hardened part. The apparatus required therefor has a porous lower mould portion (1) and is provided with a compressed-air and vacuum connection (8, 9), these inlet connections extending into an annular, air-permeable conduit, and the entire lower mould portion (1), with the exception of the mould interior (3), is surrounded by an air-tight casing (15). Such a method and apparatus permit scaffolding boards to be produced in a very economical manner, such boards being substantially lighter in weight than conventional boards formed from wood or metal and, in addition, they comply with all the regulations regarding stability and tensile strength.
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