| 摘要 |
The pre-stretching device for a thermoforming station (10) comprises a bell shaped member (11) having upper and side walls (15,16,17), defining a bottom open space; an internal partition wall (21) divides the internal space of the bell (11) into a first and a second vacuum chambers (22,23) for pre-stretching separate balls members (M', M'') from a single plastic sheet; the vacuum chambers (22, 23) are selectively connectable to respective vacuum sources (24,25) and/or to pressurised air sources (38,39). <IMAGE>
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