| 摘要 |
Appts. for joining the edges of plastic sheets comprises a seaming tool, esp. a welding tool, and a guide surface alogn which the sheets are advanced; this guide surface, viewed transversely to the seam direction, is composed of portions of alternating direction. Pref., these portions include convex and/or concave and/or straight-line sections, e.g. the transverse cross-section of the guide surface may be undulating or corrugated. In the direction of teh seams, the generatrices of the guide surface are pref. all parallel. This form of guide surface permits a folded arrangement of the sheet during welding, thus considerably reducing the floor space required. |
