Patent ID: 9004895
Filing Date: 2015-04-14
Classification: B29C,B29K,B29L

Abstract:
1. A device for thermoforming a plastic film, comprising: a chamber configured to have variable internal pressure, and having an opening in a side of said chamber; an attachment system configured to attach the film around said opening, and hold a peripheral edge of the film firmly so that said film closes off and seals the chamber; a pressure control system configured to vary and control the pressure in the chamber, and cause the film held by the attachment system to deform in the chamber opening into a deformation which varies as a function of said pressure; a measurement system configured to measure a sag of the film held by the attachment system, said measurement system being arranged outside the chamber and facing the opening of said chamber; and a heating system configured to heat said film held by the attachment system, and comprising a hot air blowing unit arranged to produce a stream of hot air flowing externally to the chamber and in contact with the film, wherein the blowing unit is configured to cause the stream of hot air to flow parallel to the film from a first lateral side of the opening of the chamber to a second lateral side of said opening, said second side being opposite said first side, wherein the measurement system compromises: a detection head configured to receive a signal from a central portion of the film held by the attachment system; a detection head displacement system configured to move said detection head closer or furter away relative to the central portion of the film; a control system configured to activate said displacement system in a manner that maintains a constant amplitude of the signal received by said detection head; and a reading system configured to read a position of the detection head.