Chain transmission assembly

A noise suppressing mechanism for a chain drive comprising:

• a sprocket including a first side and a second side and having an axle and a plurality of teeth disposed in a first plane, said teeth being disposed a first predetermined distance from said axle;
• a resilient member being disposed on at least one side of said sprocket and projecting a second predetermined distance from said axle, said second predetermined distance being less than said first predetermined distance;
• and
• a chain including engaging members for engaging the teeth of said sprocket, pin link plates being fixed by pins, and roller link plates for engaging said resilient member, said pin link plates and roller link plates being identically formed and symmetrical in a longitudinal direction;
• said resilient member absorbing noise occurring when the chain meshes with the sprocket by said roller link plates engaging said resilient member,
• wherein projecting portions are formed at intervals on a circular outer surface of said resilient member, said circular outer surface having a outwardly facing convex-shape portions between said arc-shaped projecting portions, said arc-shaped projecting portions occurring radially inward of the teeth of said sprocket, and
• wherein said projecting portions collide with said constricted portions of said link plates upon rotation of said sprocket, thereby pushing said roller chain outward in a radial direction by a predetermined distance.

A sprocket for use in suppressing noise as a chain drive engages the sprocket comprising:

• said sprocket including a first side and a second side and having an axle and a plurality of teeth disposed in a first plane, said teeth being disposed a first predetermined distance from said axle;
• and
• a resilient member being disposed on at least one side of said sprocket and projecting a second predetermined distance from said axle, said second predetermined distance being less than said first predetermined distance;
• and
• said resilient member being adapted for absorbing noise occurring when a chain having pin link plates and roller link plates meshes with the sprocket by said roller link plates engaging said resilient member, wherein the pin link plates and the roller link plates are identically formed and symmetrical in a longitudinal direction,
• wherein a circular outer surface of said resilient member includes projecting portions formed thereon at regular intervals with outwardly facing convex arcs of the circular outer surface therebetween, said projecting portions occurring radially inward of teeth of said sprocket, and
• wherein said projecting portions collide with said constricted portions of said link plates upon rotation of said sprocket, thereby pushing said roller chain outward in a radial direction by a predetermined distance, and thereby increasing a minimum wrapping radius of the chain by said predetermined distance.