Abstract: An accumulating conveyer is provided in which rollers are utilized which have a drive mechanism with a driven load-engaging portion in permanent frictional engagement with a driving portion. The drive mechanism includes an adjustable bias means so that the driving force between a driving portion and a driven portion is adjustable according to the characteristics of the loads to be conveyed. A friction pad is positioned between a disc in the driving portion and a disc in the driven portion of the drive mechanism; the two discs are urged against the friction pad by a compression spring. When the weight of a load in contact with the driven portion is below a predetermined value, the friction between the friction pad and the two discs is sufficient to cause the two discs and the friction pad to rotate conjointly thereby coupling the driving portion to the driven portion.