Abstract: The chain tensioner has an arcuate curved bow with a correspondingly shaped, perforated sheet metal part extending over its entire length and which has a U-shaped cross-section. A plastics material layer is injection moulded all around said sheet metal part. A swivel bearing is located at one end, while at the other end a support part is provided, on which the bow is pressed against the chain running externally on a sliding surface.

Abstract: A pipe for gases and liquids made of heat-resistant plastic comprises a cylindrical body with a perimetric attachment flange having bores for attachment screws and is reinforced by an integrally molded reinforcement ring which is disposed concentrically around an end of the pipe and which is provided with side extensions that concentrically surround the bores of the flange and that have a height that is the same as the thickness of the flange in proximity to the bores. The side extensions may be shaped to provide integral washers at the bottom (attaching face) of the flange.