Abstract: In a process and a device for carrying out a welding process on thermoplastic material webs, the value of the pressing force (F.sub.i) of a pair of pressure rollers is determined as a measured value representing the weld seam thickness and is used as the actual value of the controlled variable of a welding process regulating unit, and it is compared with a corresponding set value. The feed speed (V) of the welding device is used as the correcting variable of this regulating unit by increasing the speed in the case of decreasing weld seam thickness and decreasing the speed in the case of increasing weld seam thickness to compensate a possibly existing deviation.

Abstract: A plastic welding machine for producing connection seams with thermal plastic foil or thermal plastic film. The folding device includes a fix support plate and a folding plate which is provided with a U-shaped guide stop and can be pivoted back and forth between a feed position and a working position. Folding device can be folded open for introducing the edge strip of the material to be welded and then folded up where the edge strip is folded over in the shape of a U. A flat U-shaped guide sleeve is provided which may be pivoted into the folding device to produce lap joints on the two layers of the material to be welded.

Abstract: An air guiding arrangement for welding materials having plastic films includes a device to supply a uniform hot-air stream at any given air velocity. The air guiding arrangement has a nozzle which contains a swirl chamber functioning as a diffuser which tapers in the shape of a funnel. The nozzle is preceded by an adjustable air divider through which the amount of air to be supplied to the welding site is varied. The hot-air welding machine serves for a seam-shaped connection of plastic containing materials providing uniform heat distribution in the welding gap.

Abstract: A device for handling a stack of flexible articles, such as magazines comprises a bearing plate for receiving the stack of articles which either has an arched central portion or a deflecting bar for holding a stack of articles thereon in an arched location with the ends lowered in the central portion. Associated with the bearing plate is a gripping mechanism which includes gripping arms which are mounted for movement toward and away from respective ends of the articles to be gripped. Each of the gripping arms includes a holding finger which may be rotated between a horizontal position in which the fingers will engage below each end of the articles or to a vertical position in which the articles are released. When the fingers engage horizontally below the ends of the articles the gripping mechanism may be lifted to lift the articles off the bearing plate.