| 摘要 |
<p>A method of sealing a corrugated platics sheet material which comprises feeding the sheet through a pair of rollers, at least one of which is profiled, e.g. toothed, in conjunction with the application of heat, to pre-deform the sheet, and thereafter effecting sealing by the use of, e.g., an ultrasonic electrode. The latter is employed in conjunction with a further toothed wheel, and the orientation of the toothed wheels relative to one another is such as to eliminate gaps to produce a complete seal.</p> |
