| 摘要 |
1440935 Sheet forming ITW Ltd 18 Dec 1973 [19 Dec 1972] 58608/72 Heading B5A Apparatus for thermoforming two or more plastics sheets to form, e.g. a double-walled cup, or two single-walled cups simultaneously, comprises supply rolls 10, 12, a heater 14, and a clamping frame 28, 30, 32. The heated sheets can be forced into a mould cavity by a plug 18 assisted by air pressure and/or vacuum, or by air pressure supplied through a conduit in an upper die plate which seals the mould cavity. In operation, the sheets which can be of different material, one of which can be polystyrene, are fed past the heater 14. The sheets are clamped by the members 28, 30, 32, two of which are movable normal to the sheets. Air is then passed through conduit 34 to distend the sheets before plunger 18 is lowered. The plunger has a metal portion 36 and a nylon or felt portion 38. After forming a cut-off plug (22), Fig. 4, not shown, is lowered to sever the cup from the sheets before the sheets are separated and recycled. |
