Optical out-of-balance sensor for a washer

摘要

A washing machine includes a cabinet, a splash tub located within the cabinet, and a support system resiliently supporting the splash tub relative to the cabinet. A spin tub is located within the splash tub and a drive system spins the spin tub about an axis of rotation during a spin cycle. A sensor detects an out-of-balance condition during the spin cycle characterized by oscillations of the splash tub. The sensor includes a target attached to the cabinet having a reflecting surface, a light source attached to the splash tub and positioned to direct infra red light toward the reflecting surface, and a light receiver attached to the splash tub and positioned to receive infra red light reflected from the reflecting surface. The reflecting surface has a pattern of varying reflectivity so that the light receiver receives a different quantity of infra red light when the splash tub moves relative to the cabinet. The sensor produces an output signal proportional to an amount of infra red light received by the light receiver. The output signal is sent to a microprocessor which reduces the rate of spinning of the spin tub when the output signal is at a predetermined level.