Abstract: Projections colliding with constricted portions at the center of hourglass-shaped pin link plates and with constricted portions at the center of hourglass-shaped roller link plates are provided at an annular resilient body. When a roller chain starts to mesh with a sprocket, constricted portions at the centers of hourglass-shaped link plates of the roller chain can be pushed radially outwards from the sprocket by the projections of the resilient body, vibrations occurring at the roller chain meshing with the sprocket can be made small, vibrations at each part of the roller chain can be made small, collision speed when rollers of the roller chain collide with teeth bottoms of the sprockets can be reduced, and the generation of noise can be suppressed. Moreover, because hourglass-shaped link plates are used, the roller chain can be made lighter than when flat oval shaped or oval shaped link plates are used.

Abstract: A low noise roller chain includes a rigid roller made of metal and an elastic roller made of elastic material that are arranged end to end and fitted on a bushing between two opposed inner plates so as to jointly form a roller assembly. The width of the elastic roller is 13 to 45% of the overall width of the roller assembly, and the thickness of the elastic roller is larger than the thickness of the rigid roller by 5 to 25% of the thickness of the elastic roller. With the elastic roller thus constructed, noise generated upon abutment of the roller chain with a sprocket can be effectively suppressed without deteriorating the durability of the rigid metal roller. The elastic roller may be arranged in a zigzag pattern in the longitudinal direction of the roller chain.

Abstract: Projections colliding with constricted portions at the center of hourglass-shaped pin link plates and with constricted portions at the center of hourglass-shaped roller link plates are provided at an annular resilient body. When a roller chain starts to mesh with a sprocket, constricted portions at the centers of hourglass-shaped link plates of the roller chain can be pushed radially outwards from the sprocket by the projections of the resilient body, vibrations occurring at the roller chain meshing with the sprocket can be made small, vibrations at each part of the roller chain can be made small, collision speed when rollers of the roller chain collide with teeth bottoms of the sprockets can be reduced, and the generation of noise can be suppressed. Moreover, because hourglass-shaped link plates are used, the roller chain can be made lighter than when flat oval shaped or oval shaped link plates are used.