| 摘要 |
1,014,115. Seaming non - metallic sheet material. O. FRIDLUND. Dec. 30, 1963 [Jan. 14, 1963], No. 51234/63. Heading B5K. A plastic bag formed from a folded sheet of material by welding the side and bottom edges in one operation with an L-shaped electrode. As described, to form a bag-like cover, a strip of thicker plastic material 4 may be welded to one edge at the same time, the strip 4 having holes 6 for the insertion of the cover in a collection case, Fig. 1 (not shown). The counter electrode is covered with a heat insulator with a high loss-factor such as pressboard, to assist welding. A thin layer of "Teflon" (Registered Trade Mark) may be inserted between the counter electrode and the pressboard. The arm of the L-shaped electrode operating on the thicker strip 4 is transversely rifled, and not covered, while the arm operating on the sheet material only is covered with rubber. |
