| 摘要 |
731,505. Seaming non-metallic sheet material. CHIZY, M. C. DE., and MONTAGNON, P. Sept. 1, 1953, No. 24148/53. Class 42 (1). Sheets 2, 3 of plastic material are seamwelded together by superposing the sheets and seam - welding them adjacent their edges, opening the sheets out flat alongside each other, folding back on to each sheet the edge portion 2a or 3a beyond the weld, and effecting on the first weld, but in a direction perpendicular thereto in the region 4, a second weld while at the same time the edge parts 2a, 3a are welded to their respective sheets 2, 3. Electrodes effecting a cut simultaneously with the weld may be used for the first weld, in which case edges 2a, 3a may be very short. In a modification of the process, edges 2a, 3a are both turned down on to the same sheet 2 or 3. |
