Thermoforming apparatus with frame corner beams and platen closing mechanism

A thermoforming apparatus, comprising:

• a frame having an array of laterally spaced apart frame corner beams of substantially uniform length configured to carry tensile loads during a forming operation;
• a pair of opposed platens carried by the frame contained within the array of frame corner beams each with an article forming member, one article forming member configured to engage an opposed face of another article forming member across a heated sheet of thermoformable material;
• a seal provided by one of the dies configured to seal the sheet with the one article forming member when engaged with the another article forming member;
• a toggle shaft carried by the frame for rotation outboard of the platens and the article forming members;
• a kinematic linkage coupled between the toggle shaft and one of the dies to provide a platen closing mechanism that engages the article forming members and the seal with the sheet in a sealed forming position, the platen closing mechanism having symmetric and opposed closing arms spaced laterally outboard of the pair of opposed platens, contained laterally inboard of the array of frame corner beams and configured to cyclically separate and engage together the platens and maintain parallel closed engagement between the platens when closed in the sealed forming position;
• a form air manifold and a source of differential pressure having a force actuator coupled with a face on one of the article forming members, contained laterally inboard of the array of frame corner beams configured to generate forming pressure;
• and
• a seal maintaining mechanism including a pair of articulating bearing assemblies carried by the frame outboard of the platens having drive arms contained laterally inboard of the array of frame corner beams and configured to support the at least one toggle shaft for translation towards and away from the another article forming member and platen configured to maintain the sealed forming position under the forming pressure.

A thermoforming apparatus, comprising:

• a frame having an array of laterally spaced apart frame corner beams of substantially uniform length configured to carry tensile loads during a forming operation;
• a pair of opposed platens and article forming members carried by the frame contained within the array of frame corner beams to engage oppositely across a heated sheet of thermoformable material;
• a seal provided by one of the article forming members configured to seal the sheet with the one article forming member when engaged with the another article forming member;
• a pneumatic form air source configured between the heated sheet and one of the article forming members to generate a forming pressure;
• and
• a two-stage force applicator comprising:
• (a) a platen closing mechanism having closing arms contained laterally inboard of the array of frame corner beams configured to reciprocate at least one of the platens together and apart relative to another of the platens to a sealed forming position, and (b) a seal maintaining mechanism having a force actuator provided between one of the article forming members and the frame outboard of one of the platens contained laterally inboard of the array of frame corner beams carrying the one article forming member and configured to generate a force that maintains the sealed forming position under the forming pressure, the platen closing mechanism having symmetric and opposed closing arms spaced laterally outboard of the pair of opposed platens and configured to cyclically separate and engage together the platens and maintain parallel closed engagement between the platens when closed in the sealed forming position.