Patent ID: 7857720

Claim:
A synchronous belt drive system comprising: an obround sprocket ( 10 ) having a toothed surface and at least one linear portion ( 16 ) connecting and separating by a predetermined length two arcuate portions ( 14 , 15 ), the arcuate portions having a constant radius (R 1 , R 2 ), the linear portion having the predetermined length; a second sprocket ( 300 ) having a toothed surface, the second sprocket engaged to the obround sprocket by an endless toothed member ( 200 ); the second sprocket connected to a rotary load, the rotary load having cyclic torque fluctuations; and a radius (R 1 ) of the obround sprocket ( 10 ) oriented at a belt entry point ( 201 ) which coincides with a maximum amplitude of a cyclic torque fluctuation such that a span length (SL) beginning at said entry point and extending to said second sprocket of the endless toothed member is made to vary in a manner that substantially cancels the cyclic torque fluctuations.