Centrifugal control assembly for camshaft advance and retardation and suppression of cyclical vibration

A timing sprocket assembly for attachment to a camshaft of an internal combustion engine having a crankshaft, for receiving drive forces from a timing chain and transmitting driving forces from said timing chain to said camshaft comprising:

• a hub attachable to and rotatable with said camshaft;
• a pair of centrifugally displaceable pivotal levers supported for pivoting movement relative to said hub;
• a ring sprocket circumscribing said hub and said levers;
• said levers engaged with said ring sprocket and effective to displace said ring gear rotationally relative to said hub under rotationally induced centrifugal displacement of said levers;
• and
• a flywheel coupled to and rotatable with said camshaft,
• whereby said levers displace said ring sprocket to a position relative to said camshaft such that said camshaft is retarded with respect to said crankshaft.

A method of advancing a valve control camshaft relative to a timing sprocket in an internal combustion engine during low range engine speeds and retarding said valve control camshaft in an internal combustion engine during high range engine speeds, comprising the steps of:

• driving said camshaft timing sprocket in synchronism with said camshaft;
• rotationally displacing said camshaft with respect to said timing sprocket responsive to increased engine speed;
• wherein said step of displacing includes the step of rotating a centrifugally responsive lever about an axis of rotation of said camshaft;
• increasing said rotation of said lever to a rotational speed sufficient to overcome any resilient resistance to movement of said timing sprocket with respect to said camshaft;
• responsive to centrifugal displacement of said lever, rotationally translating said timing sprocket relative to camshaft in a direction identical to said rotation of said timing sprocket,
• coupling said timing sprocket to said camshaft in a solid drive connection;
• whereby said camshaft is advanced relative to said crankshaft position at low speeds and retarded at higher engine speeds,
• thereby providing a relative camshaft position most productive of engine torque at both low engine speeds and higher engine speeds.