A fuel level sensor has a rotor with two magnets mounted for rotation therewith, the magnets spaced from one another and with like poles directed toward one another. A Hall effect sensor on the housing is positioned between the two magnets such that increasing the volume of fluid in the tank moves one magnet toward the sensor and decreasing the volume in the tank moves the other magnet toward the sensor. A metal sleeve around the magnets protects the parts from interference from magnetic material in the fuel. A static discharge path is provided from a metal rod connecting a float, a plate contracting the rod, and a pivot pin retaining the rotor to the housing, and a ground connector in contact with the pivot pin. |
Citations|
| US4804944 | Sep 1, 1987 | Feb 14, 1989 | | Hall effect liquid level sensing apparatus and method | | US4920797 | Jan 9, 1989 | May 1, 1990 | Schaevitz Sensing Systems, Inc. | Fluid level sensor | | US5341679 | May 14, 1993 | Aug 30, 1994 | G.T. Products, Inc. | Resistor card fuel level sender with float arm actuator | | US6508121 | Mar 20, 2001 | Jan 21, 2003 | Mannesmann VDO AG | Filling level sensor | | US6679116 | Jan 7, 2003 | Jan 20, 2004 | Rochester Gauges, Inc. | Liquid level gauge with removable Hall device | | US6734667 | May 2, 2003 | May 11, 2004 | Sensor Solutions Corporation | Angular position sensor | | US6813946 | Jun 9, 2003 | Nov 9, 2004 | Markem Corporation | Liquid sensing | | US20030112004 | Feb 19, 2002 | | | MAGNETIC POSITION SENSOR HAVING SHAPED POLE PIECES FOR IMPROVED OUTPUT LINEARITY | | US20050103103 | Nov 17, 2003 | | | Fuel level sensor | | US20050109105 | Oct 19, 2004 | | | Liquid level indicator using lights |
Referenced by|
| US7621182 | Apr 9, 2007 | Nov 24, 2009 | | Sealed fuel level detector | | US7640800 | Oct 2, 2006 | Jan 5, 2010 | Siemens Aktiengesellschaft | Filling level sensor |
Claims1. A fuel sensing device for sensing the level of fuel in a tank comprising - a first member and a second member,
- one of said first and second members attached to said tank,
- the other of said first and second members moveable with a surface level of fuel in said tank,
- a first and a second magnet on said first member wherein said first and second magnets are spaced from one another and like poles of said magnets are directed generally towards each other,
- a detector on said second member for detecting magnetic field strength,
- said detector positioned between said first and second magnets with a first spacing separating said detector from said first magnet and a second spacing separating said detector from said second magnet wherein said first spacing is increased as said fuel level rises and said second spacing is increased as said fuel level falls.
2. The fuel sensing device of claim 1 wherein one of said first and second members is a rotor and the other of said first and second members is a housing and said fuel level sensor further comprises - a metal pin rotatably joining said rotor to said housing, and
- a static discharge path extending through said metal pin.
3. The fuel sensing device of claim 2 and further comprising a metal shield surrounding said means for detecting and said first and second magnets. 4. The fuel sensing device of claim 3 wherein said metal shield is a tubular sleeve having a flange at one end and - said flange serves as a bearing surface between said rotor and said housing.
5. The fuel sensing device of claim 1 and further comprising a metal shield surrounding said detector and said first and second magnets. 6. A fuel level sensor comprising - a housing,
- a rotor,
- a metal arm extending from said rotor,
- a metal pin rotatably joining said rotor to said housing,
- a pair of spaced magnets on one of said housing and said rotor,
- a detector on the other of said housing and said rotor for detecting field strength wherein a spacing between said detector and a first of said magnets is reduced as a level of fuel in said tank increases and a spacing between said detector and a second of said magnets is reduced as said level of fuel in said tank increases,
- a metal shield around said pair of meg nets and said detector, and
- a static discharge path passing through said pin.
7. A fuel level sensor for sensing a level of fuel in a tank, said fuel level sensor comprising - a housing,
- a rotor,
- a magnet in one of said housing and said rotor,
- a detector on the other of said housing and said rotor for detecting magnetic field strength, and
- a metal shield around said magnet and said detector wherein said metal shield will enhance a magnetic field from said magnet and attract ferrite particles suspended in said fuel.
8. The fuel level sensor of claim 7 and further comprising - a metal pin rotatably joining said rotor to said housing, and
- a static discharge path extending through said pin.
9. The fuel level sensor of claim 7 wherein said shield is a metal sleeve having a radial flange and said radial flange abuts a surface on one of said rotor and said housing to form a bearing surface between said rotor and said housing. 10. The fuel level sensor of claim 9 and further comprising - a metal pin rotatably joining said rotor to said housing, and
- static discharge path extending through said pin.
11. A fuel level sensor comprising a plastic housing, a plastic rotor, a metal float arm, and a metal pin rotatably joining said rotor to said housing, and a static discharge path extending from said metal float arm and through said pin, a magnet, a magnetic field strength detector, and a metal shield around said magnet and said magnetic field strenath detector wherein said metal shield will enhance a magnetic field from said magnet and attract ferrite particles suspended in said fuel. 12. A position detector for detecting the position of a first object with respect to second object comprising - a first member having a pair of spaced apart magnets mounted thereon,
- said spaced apart magnets having like poles directed towards one another,
- a second member having a Hall effect detector mounted thereon,
- said Hall effect detector positioned between said like poles of said spaced apart magnets, and
- means for connecting one of said first and second members to said first object,
- means for connecting another of said first and second members to said second object, and
- one of said first and second members moveable with respect to another of said first and second members wherein said Hall effect sensor is moveable toward one of said spaced apart magnets and away from another of said spaced apart magnets in response to movement of said first object with respect to said second object and said Hall effect sensor detects said movement of said first object with respect to said second object.
13. The position detector of claim 12 and further comprising - readout means connected to said Hall effect sensor wherein a readout of said Hall effect sensor is related to said movement.
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