| 摘要 |
<p>1489418 Sheet forming DOW CHEMICAL CO 29 Nov 1974 [3 Dec 1973] 51773/74 Heading B5A An expandable plug for use with a cavity mould to produce hollow articles from thermoplastic sheet, comprises a plurality of segments 12 secured pivotally at one end 14 to a flange 16 and adapted to be moved apart by a cam 22 against the action of a compression spring 26 by an axially movable rod 24, the segments being covered by a cover 30, e.g. of rubber. Heating or cooling fluid can be circulated within the cover. The plug can be oval or square shaped, and can be made of steel, aluminium, wood, plastics, e.g. nylon, or rubber.</p> |
