| 摘要 |
<p>For use with a thermoforming press adapted to form individual articles in the body of a thermoplastic web which has a degree of inherent stiffness, a trimming station for trimming the formed articles from the web subsequent to their formation characterized by a web transport that comprises at least a pair of rotary advancing devices directly engaged with the web at spaced apart locations across the width of the web, a drive for periodically rotating the advancing devices to produce indexing movement to the trimming press and means to periodically release the drive engagement of the rotary advancing devices with the web to enable relaxation of stress developed in the thermoplastic web and to allow the interaction of the web with the guides to realign the web in the absence of constraint by the rotary advancing devices, and the method of operation thereof. In the embodiment shown the rotary advancing devices positively engage the web, the drive is accurately controlled to move the web a predetermined distance after sensing of the approach of the formed article toward the trimming position, and the release of the advancing means occurs after the trim die has engaged the web, during selected trim cycles.</p> |
