Abstract: A tentering chain is assembled of inner links and outer links or link plates interconnected by journal pins passing through the outer link plates and through the inner links so that the latter are positioned between the outer link plates. The inner links have plates which are provided with integral bearing bushings that are interconnected at a junction (J) formed by pressing four bearing bushings together with a transition fit after a bearing roller has been placed on each of two of the four bushings to form the inner links. The inner link plates form with their bearing bushings two chain link sections (1, 2) that are easily interconnected at the junction (J) and also easily disconnected again at the junction. Both sections are made by casting or drop forging.

Abstract: Lengthwise stretching machines for thermoplastic synthetic films are equipped with mechanical or opto-electrical devices for detecting a tearing of the film or an accumulation of film on the stretching rollers and for stopping the machine when tearing or accumulation occurs, to protect the stretching rollers. Unallowable loads and possible damage to the roller bearings are avoided by mounting the bearing housings (1, 2) of each roller (3, 4, 5) of a lower roller (7) in the machine frame for cooperation with a force generating device (8) which presses the respective bearing housing (1, 2) toward oppositely located rollers (9, 10, 11) of an upper roller group (12) to an extent permitted by stops (14, 15) rigidly arranged on the machine frame (13). The rollers (3, 4, 5) of the lower group received in the bearing housing (1, 2) can overcome the pressing force of the device (8) to slide in a yielding direction away from the upper rollers, when a roller accumulates film thereon.

Abstract: A tentering chain is guided between two guide rails extending in parallel to each other. One guide rail (19a) is an outer guide rail with regard to a course followed by the chain, while the other guide rail (19b) is an inner guide rail. The chain links are hinged to each other by a journal pin which carries a first guide roller on an inner pin section between chain link plates, and a second guide roller on a cranked outer pin section. Thus, the rotational axes of these two guide rollers extend in parallel to each other and spaced from each other, so that one guide roller can only contact one guide rail, but not the other and vice versa. This feature prevents the reversal of the rotation direction of the guide rollers as they travel along the parallel guide rails.