Appliance latch with uni-directional actuator

An electric lock for a household appliance having a door that may be locked when the door is in a closed position by receipt of a bolt extending along an axis from an appliance frame to be received by the door in the closed position, the electric lock comprising:

• a housing fixable to the appliance frame;
• a bolt attached to be movable with respect to the housing to extend to a lock position with respect to the appliance frame to the door in the closed position to lock the door and to retract to an unlock position with respect to the appliance frame to unlock the door allowing the door to move from the closed position to an open position;
• an electromechanical actuator communicating with the bolt and actuable by an electric signal to urge the bolt along the axis:
• a spring communicating with the bolt to urge the bolt along the axis and having a force sufficient to move the bolt when the electromechanical actuator is not actuated;
• and
• a bi-stable mechanical linkage attached to the bolt to hold the bolt at a stable position resisting movement by the spring and then to release the bolt from the stable position allowing movement by the spring with successive actuation of the electromechanical actuator;
• wherein the bi-stable actuator operates to release the bolt to extend further beyond the lock position with respect to the unlock position to an over-travel position and further including contacts providing an electrical signal distinguishing between whether the bolt is in the unlock position or the over-travel position.