Abstract: A synchronous belt drive system having: a synchronous belt with a tensile cord of high-modulus fiber such as glass, carbon, PBO, or aramid; a driver sprocket and at least one driven sprocket, at least one of which is an obround sprocket; and a tensioner having: a base having a cylindrical portion extending axially with a radially outer surface and a receiving portion, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm. Preferably, no one of the eccentric arm, pulley, or torsion spring is axially displaced along an axis A-A from the others. The obround sprocket has a toothed surface and at least one linear portion disposed between two arcuate portions having a constant radius, the linear portion having a predetermined length.

Abstract: A synchronous belt drive system comprising a first obround sprocket having a toothed surface and at least one linear portion disposed between two arcuate portions, the arcuate portions having a constant radius, the linear portion having a predetermined length, a sprocket having a toothed surface, the sprocket engaged to the first obround sprocket by an endless toothed member, and the first obround sprocket having a magnitude and a phase such that an angular displacement timing error between the sprocket and the first obround sprocket is less than 1.5 degree peak to peak.

Abstract: A synchronous belt drive system having: a synchronous belt with a tensile cord of high-modulus fiber such as glass, carbon, PBO, or aramid; a driver sprocket and at least one driven sprocket, at least one of which is an obround sprocket; and a tensioner having: a base having a cylindrical portion extending axially with a radially outer surface and a receiving portion, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm. Preferably, no one of the eccentric arm, pulley, or torsion spring is axially displaced along an axis A-A from the others. The obround sprocket has a toothed surface and at least one linear portion disposed between two arcuate portions having a constant radius, the linear portion having a predetermined length.

Abstract: A synchronous belt drive system comprising a first obround sprocket having a toothed surface and at least one linear portion disposed between two arcuate portions, the arcuate portions having a constant radius, the linear portion having a predetermined length, a sprocket having a toothed surface, the sprocket engaged to the first obround sprocket by an endless toothed member, and the first obround sprocket having a magnitude and a phase such that an angular displacement timing error between the sprocket and the first obround sprocket is less than 1.5 degree peak to peak.

Abstract: A timing error correction system comprising a three element linkage having at least one element pivotally mounted to a mounting surface, a timing belt engaged between a driver and a driven, a first element of the three element linkage in contact with a timing belt slack side, a second element of the three element linkage in contact with a timing belt tight side, and a spring imparting a load to the three element linkage.