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AssigneeConvenience Food Systems B.V. of the Netherlands
InventorsJean-Claude Rolle, Kurt Sjödin
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The inventive method serves for producing open containers from a flat sheeting (4) consisting of a foam material or containing at least one layer of such a material, by drawing the sheeting with the help of a female (2) and a male tool (1) and by expanding the foam material with the help of a pressure reduction. The action sequence of one cycle of the inventive method is e.g. the following: positioning and clamping the sheeting (4) over the opening of the recess in the female tool (2); moving the male tool (1) into the recess and at the same time prestretching the sheeting with the help of a pressure difference between its two sides, such that the face of the male tool (1) gets in contact with the prestretched sheeting inside the recess; drawing the sheeting further by moving the male tool (1) to its end position in the recess of the female tool (2) and at the same time reducing the pressure on the female tool side or on both sides of the sheeting such that it reaches a value below ambient pressure which is sufficiently low for expanding the foam material and keeping the reduced pressure until the sheeting is cooled below plastication temperature; then equalizing the pressure and demolding and declamping the formed container and advancing the sheeting for a further method cycle.
Method for forming open containers from a flat thermoformable sheeting (4) consisting of foam material or containing at least one layer of such material with the help of a cooperating pair of a female tool (2) with a recess and a male tool (1) movable into the recess of the female tool (2) thereby drawing the flat sheeting (4) positioned over the opening of the recess and having an elevated temperature above its plastication temperature, wherein during the movement of the male tool (1) towards the female tool (2) and to its end position in the recess of the female tool thereby contacting and drawing the sheeting, the pressure on at least one side of the sheeting is reduced such that it reaches a value below ambient pressure which is low enough for expanding the foam material when the male tool (1) is reaching or has just reached its end position and that the reduced pressure is maintained until the sheeting temperature is below the plastication temperature of the foam material, characterized in that the sheeting positioned over the recess of the female tool is prestretched into the recess with the help of a pressure difference between the male tool side of the sheeting and the female tool side, such that the face of the moving male tool (1) contacts the sheeting inside the recess.
Dependencies are inferred from the claim text.