Cloth detection system for an automatic washer

摘要

An automatic washing machine having an automatic liquid level control system including an ultrasonic transmitting and receiving arrangement. The automatic washer includes a vertical axis tub disposed within a cabinet and further having a rotatable perforate wash basket disposed within the tub for receiving a load of clothes and a quantity of washing liquid. The cabinet includes an openable lid disposed above the tub and the wash basket. A transducer is provided, mounted in the cabinet lid, for operating in a first mode as a transmitter for transmitting a sonic pulse into the wash basket. The transducer operates in a second mode as a receiver for generating an electronic signal responsive to receipt of a sonic echo pulse from the surface of the load of clothes disposed within the wash basket. The height of the load of clothes may then be determined in accordance with the elapsed time between transmission of the sonic pulse and reception of the corresponding sonic echo pulse. The wash basket is controlled to rotate while a plurality of sonic pulses are generated and the corresponding sonic echo pulses are received such that a plurality of clothes load heights values are measured and stored. From the plurality of clothes load height values, an average clothes load height and an average clothes height deviation value may be determined. An optimum quantity of washing liquid may then be determined in response to the calculated average clothes load heights and the average clothes height deviation value.