Patent ID: 8167578

Claim:
An assembly for controlling the level of a liquid in a vessel in which a submersible pump is disposed, the pump powered by a motor housed in a motor housing thereof, the motor energized by an external power source, the level control assembly comprising: a switch housing; a float housing, arranged in close proximity to the switch housing; a float, disposed in the float housing and operative to move therewithin responsive to the liquid level in the vessel; a switch, disposed in the switch housing and operative to selectively connect the motor to, and disconnect the motor from, the external power source; means for coupling the operation of the switch to the level of the float through interacting attractive magnetic force fields, the means comprising: a first magnet, in the float housing and attached to the float, the magnetic force field thereof having an axis that is aligned with a vertical longitudinal axis of the float; a second magnet, in the switch housing, the first and second magnets arranged such that the respective force fields are attractive, the second magnet arranged to activate the switch as the respective magnets approach each other and to deactivate the switch as the magnets move apart; and means for changing a relative angular relationship of the force field between the respective magnets as the magnets move toward and away from each other, comprising a lever having a path of limited arcuate rotation, so the force field axis of the second magnet is tilted away from the force field axis of the first magnet as the respective magnets approach each other and the lever bears against, and activates, the switch as the magnets approach each other.