| 摘要 |
<p>1,256,700. Sheet forming. SOC. DES ACCUMULATEURS FIXES & DE TRACTION. 30 Dec., 1968 [28 Dec., 1967], No. 61769/68. Heading B5A. [Also in Division H1] A vacuum moulding apparatus comprises a chamber 1 closed by perforated plate 1 carrying moulds 4 and mounted on perforated hollow pistons 7, a cover 8 having vents 11, and suspended therefrom heating elements 10, e.g. infra-red lamps. A strip 12 of plastics material is unwound from reel 13 and placed between members 1, 8. Cover 8 is lower to pinch the strip 12 between rim 2 and frame 9 in an airtight manner. After the strip has been heated air is injected into chamber 1 via the hollow pistons 7 to stretch and blow thestripinto position 12<SP>1</SP>. Without further heating- a vacuum is created in chamber 5 via pistons 7 and the strip is drawn into conformity with. plate 3 and forming depressions in the strip corresponding to moulds 4. Screen 6 through which the moulds 4 protrude limits the action of the vacuum to the periphery of the moulds. Cover 8 is raised and air is blown over the strip to cool and harden it. Lowering plate 3 by pistons 7 disengages the strip.</p> |
