Abstract: A tensioning and damping element for endless chain drives, especially for roller chain drives, can be used for endless chain drives, which are to be tensioned diametrically. The material is an elastic plastic. All told, the known tensioning and damping elements, in conjunction with the wear of the chain, the load changing phases, as well as the reversing according to the degree of deformation, have the disadvantage of a phased running irregularity, an increased running noise and of wear-intensive areas in the toothed rim. An element with a ring part and a toothed rim of arc-shaped teeth with, in each case, axially opposite bulges in the roller-seating and, between these, roller-seating depressions, grooves, which are disposed peripherally between the ring part and the bulges, an extended pitch and extended roller-seatings with the advantageous profile shape similar to a semielliptical curve lying on the root circle.

Abstract: A tensioning and damping element for chain drives, which comprises an elastically deformable ring part and a toothed rim arranged at the periphery thereof, the ring part being circular in the stress-free, uninstalled state and assuming, in the stressed, installed state, an ellipse-like shape between a non-loaded strand and a loaded strand of the chain drive, the toothed rim engaging with the non-loaded strand and the loaded strand and in so doing transmitting to the two strands a tensioning force which is caused by the ellipse-like deformation of the ring part. The ring part is constructed in such a manner that its cross-sectional profile steadily changes with increasing deformation of the ring part, in such a manner that the ratio of the height of the cross-sectional profile to the width of the cross-sectional profile in the maximally biased state of the ring part is at least 4% smaller than in the stress-free state of the ring part.