Abstract: A door locking device for an appliance such as a washing machine has a rotatable lock lever actuated to engage a latch carried by the door to hold the door in a closed position. The lock lever is actuated by a bimetallic element which is adapted to be connected in series with the drive motor when the washing machine is in the spin condition so that the electric current passing through the drive motor passes through the bimetallic element and the resulting heating and deflection of the bimetallic element actuates the lock lever. The unit also carries an interlock switch actuated by the latch mechanism to prevent operation when the door is open. A shunt switch is provided to close electrical contacts when the bimetallic element and lock lever are deflected to the locked position to shunt current past the bimetallic member to prevent further heating and to insure a substantially constant unlock time.

Abstract: The cycles of an oscillator varying in frequency in proportion to the changing level of a monitored liquid are counted over a fixed period of time. A derived submultiple of the count is compared relative to an electronically stored table of numbers indicative of known liquid levels. Predetermined relationships between the count and the table initiate control functions for maintaining or varying the level of monitored liquid during a programmed series of operations such as, for example, the programmed cycles of a microcomputer controlled clothes washing machine.

Abstract: A safety interlock for a door of an automatic washing machine is disclosed. The interlock securely latches the door during a spin cycle to prevent the operator of the machine from opening the door and catching his hand in the rotating motor driven drum. The interlock operates during operation of the motor and during a time delay period following de-energization of the motor to permit the drum to coast to a safe speed or to a stop. Included in the interlock is a switch member operable upon closure of the door to at least partially complete a circuit between the motor and a bimetallic element. The remainder of the circuit is completed by a timer driven switch, and when the circuit is completed the bimetallic element is heated to move a latch on the frame of the appliance into locking engagement with a latch on the door.