Patent ID: 7188521

Claim:
A liquid level measuring system that actuates an indicator assembly in response to depth of a liquid confined to a container, comprising: a housing arranged to be mounted to the container a flexible coupling having a first end and a second end, the first end being connected to the housing; a tubular frame connected to the second end of the flexible coupling so that the tubular frame is suspended in the container, the flexible coupling being arranged to maintain the tubular frame in a vertical orientation in the container when the actuator and the housing are out of vertical alignment, the tubular frame having a 270° rifling groove therein; a float mounted in the tubular frame, the float having a projection that extends from a side portion thereof into the rifling groove so that the float is force to rotate as it moves vertically in the tubular frame, the float having a central lengthwise passage therein; a drive rod mounted in the tubular frame to extend lengthwise therethrough and to extend through the central passage in the float, the central passage and the drive rod being configured such that rotation of the float in the tubular frame causes the drive rod to rotate, the drive rod having an upper end that is connected to the flexible coupling so that the flexible coupling rotates with the drive rod; a magnetic coupler assembly arranged to transfer movement of the flexible coupling to the indicator, the magnetic coupler assembly including: a first dielectric disc connected to the flexible coupling, the first dielectric disc having three magnets mounted thereon with their poles facing upwards; and a second dielectric disc connected to the indicator assembly, the second dielectric disc having three magnets mounted thereon with their poles facing downwards such that opposite poles mounted on the first and second dielectric discs are arranged with opposite poles in facing relationship such that magnetic forces transfer rotation of the drive rod to the indicator assembly.