| 摘要 |
<p>775,395. Scanning non-metallic sheet material. FLAX, V. March 24, 1955 [March 24, 1954], No. 8585/55. Class 42 (1). [Also in Group XI] Flexible containers formed of a thermoplastic material are sealed by pressing the container walls together between welding dies supplied from a high frequency current source through an oscillatory circuit the frequency of which is dependent upon the distance apart of the dies and which is brought into resonance only when the dies reach predetermined relative positions in which their separation is less than the combined thickness of the walls to be welded together. The welding dies may be continuously connected to the high-frequency current source, welding taking place automatically upon the dies reaching their predetermined positions.</p> |
