Isolated thrust pin for use with a rotating shaft

Balancing devices or systems have been used to compensate for the periodic unbalanced forces generated by the reciprocating movement of the piston and connecting rod assemblies of an engine. These devices in the past have reduced serviceability, increased engine component complexity, increased cost and have reduced reliability. The subject device provides a simple, inexpensive, more serviceable and reliable balancing system. A plurality of individual bearing supports are removably attached to the engine, a pair of balancing shafts are rotatably positioned in the supports and a thrust pin is isolatingly mounted between the support and the shaft. A pair of o-rings are mounted about each end of the pin and is positioned in the support at least partially isolating the pin from the engine. The center of the pin has a plurality of seating surfaces thereon which have an oil film between the seating surfaces and a groove in the shaft. The balancing system is separate from the engine and can be easily added or removed. Thus, the system isolates the axial loads from the engine to the balancing system and is simple, inexpensive and reliable.