US Patent 12123422 Fan device for engine loading

A fan apparatus may include a frame, a fan, and a drive mechanism. The fan may be supported for rotation relative to the frame and may include a fan shaft and a plurality of blades extending outward from the fan shaft. The drive mechanism may include a driven wheel, a drive shaft, a first drive wheel, a second drive wheel, and a torque-transmission loop. The driven wheel may be mounted on the fan shaft. The drive shaft may be supported for rotation relative to the frame. The first drive wheel may be mounted on the drive shaft. The second drive wheel may be mounted on the drive shaft. The torque-transmission loop may be engaged with the driven wheel and a selected one of the first and second drive wheels.