A conveyor belt cleaner system comprising a plurality of scrapers for contacting and cleaning a conveyor belt includes an adjustable, internal torsion assembly that avoids external springs. A scraper assembly comprises an elongated, generally tubular torque arm of square cross section having an integral, upwardly projecting flange that mounts the scrapers. The torque arm is mounted for rotation radially toward or away from the conveyor belt between suitable brackets. Internal Z-shaped torsion springs extend generally from the brackets to the torque arm interior. The springs yieldably bias the scraper assembly against the conveyor belt. One leg of the Z-shaped springs is torsionally locked within the torque arm between opposed corners, and the opposite end terminates in a drive key projecting from the brackets. Preferably a ratchet system is employed to lock the torque arm in a desired tension. A variety of different scraper blade shapes and configurations can be used. Primary cleaners are preferably formed of urethane. In one embodiment, trunnions extending from the brackets over the spring legs are coaxially, telescopingly received within the torque arm.