Patent ID: 8211355

Claim:
A method of forming plastic articles, said method comprising: (I) utilizing a rotary forming drum, said rotary forming drum comprising in combination: a vacuum distribution and control system, a plurality of pivoting trays connecting two spaced-apart drums; said vacuum distribution and control system comprising a vacuum zone, said vacuum zone comprising a vacuum induction plate, a vacuum zone plate and a vacuum adaptor plate; said vacuum induction plate being mounted to said forming drum and containing a plurality of openings therethrough; said vacuum zone plate surmounting said induction plate and having an arcuate slot adjoining the plurality of openings through said induction plate; said adaptor plate being surmounted on said vacuum zone plate with an opening therethrough to permit vacuum flow therethrough; vacuum hoses connecting said vacuum distribution and control system to said trays; each said pivoting tray being controlled by a roller cam, a cam follower, internal return springs, and external return springs, wherein each pivoting tray is capable of outward movement away from the rotary forming drum, effected by the cam follower and the roller cam, each pivoting tray containing forming inserts, said rotary forming drum having a top portion and a bottom portion; (II) feeding thermoformable plastic to the rotary forming drum onto the top portion while rotating the drum; (III) drawing a vacuum on a portion of the forming tray inserts to draw the thermoformable plastic into the forming tray inserts; (IV) holding the vacuum on the said tray inserts until the thermoformable plastic has conformed to the forming inserts in the tray to form molded parts; (V) extracting the thermoformable plastic containing the molded parts from the rotary forming drum near the bottom portion of the rotary forming drum.