Title of Invention	A FLUID LEVEL SENSOR
Abstract	Instant invention is related to a fluid level sensor comprising: a float mounted onto a float guide with a helicaid spring, wherein linear movement of the float with the fluid level variation rotates the helicaid spring, and a sensor to detect angular motion of the helicaid spring to determine the fluid level. Figure 1.

Full Text

FIELD OF INVENTION The present invention relates to a non contact type fuel level sensor with Hall Effect principle for automobile / marine applications. This invention relates generally to tubular fuel level sensors and, more particularly, to fuel level sensors for use with recreational vehicle fuel tanks, such as those found on Car, LCV, HCV, Off road vehicle, snowmobiles, etc. These types of fuel sensors are fitted in the vehicle fuel tank to measure the fuel level. An indicating instrument will be used in conjunction with the fuel sensor to read the fuel level in the tank. BACKGROUND OF THE INVENTION Numerous design constraints are imposed upon fuel level sensors, particularly fuel level sensors for use with recreational vehicles. This invention of fuel level sensor is sleek in design and light in weight. Product height can vary depend on the tank size. Fuel level sensors known for monitoring the level of fuel within a tank are resistive, ultrasonic, electromagnetic, and shaped electromagnetic field in nature. Resistive type sensors rely on contact connections to a resistive element. A float and a pivot arm move such that when the fuel tank is full, the wiper contact is at one extreme of the resistive element, and when the tank is empty the wiper contact is at the other extreme. It is known that such contact type sensors wear over time, making non- contact type sensors desirable. Ultrasonic, electromagnetic, and shaped electromagnetic field sensors have complex electronics to drive the sensor element and determine the fuel level. Their complexity makes component costs high. For many years automotive manufactures have relied on the resistor card technology to provide a feasible and economical fuel level sensing approach for use in motor vehicles. resistor card is not a cost effective solution for fuel level sensing when its characteristics of product reliability and service life are considered. The major fault of the resistor card is its reliance on a mechanical wiper to maintain electrical contact to the resistive element within its assembly. Level sensors that incorporate a mechanical contact have a number of well-known problems. The mechanical movements within any mechanism make those components susceptible to wear, fatigue, and loosening. This is a progressive problem that occurs with use and leads to eventual failure after a sufficient amount of movement has occurred. Another problem experienced with the resistor card is its inability to survive long- term exposure to newer types of fuels now used in automobiles. Exposure to Methanol, Ethanol, peroxide and other fuel additives are known to breakdown the inking adhesives used in making the resistor element of the card. Eventually contact of the wiper and the resistive element opens causing operational failure of the level sensor. One solution to overcoming the inherent problems of mechanical type sensors like the resistor card is found in non-contact type sensors. Non-contact type sensors product is the reed switch and magnet latching type this product is having one protective tube housing, a magnet carrying float, magnetically latched reed-switches located at different locations in a serial electrical circuit. The quantity of reed switch and resistors are selected depend on the product height or the accuracy required for the end user. The mounting cap is made out of reinforced plastics and compatible for fuel like gasoline; gasoline+methonal mixer; etc. The float is guided by a tube, which will protect from liquid slash. The intention will be smooth, as the float is not disturbed by the fuel slash. An embedded printed circuit board is placed inside the tube. These boards are supported with protective placed to avoid reaction with fuel. These boards are suitable for used in gasoline; diesel; water. The float fixed with one magnet to activate the reed switches. The activation of reed switch is based on the principle of biasing a reed switch with another magnet will allow normally closed operation. Bringing another magnet of opposite polarity, in close proximity to the magnet/reed switch assembly will open the contacts. Also, using a biasing magnet will allow reed switch operation in the hold area or hysteresis area, there by creating a latching sensor, in this situation, real care needs to be taken in exact placement of the biasing magnet and the operating magnet needs to be restricted to certain areas. To switch from bi-stable state to bi-stable state the operating magnet's polarity or direction needs to be reversed and also cost of the product is too high. To overcome the above said, in recent years magnetic flux sensor technology, particularly that of the Hall effect sensor, has developed into a robust and reliable technology. Even advanced features of functional diagnostics can be integrated into the Hall effect circuitry. The integration of custom circuitry with the Hall effect sensing element makes it possible to produce Hall effect sensors that have advanced features like analog, PWM, and digital output capability. Compensation circuitry now available in Hall effect sensors allow for much greater accuracy and linearity over operating temperatures. Hall effect sensors now offer programmable features that permit adjustable control of output signal radiometry, sensitivity, voltage offset, temperature coefficient, and output signal range limiting. Thus, it would be advantageous to provide a fuel level sensor that utilized magnetic flux sensor technology in order to provide an accurate, compact, and rugged fuel level sensor. OBJECTS OF INVENTION The principle objective of the present invention is to develop a fluid level sensor comprising: a float mounted onto a float guide with a helicaid spring, wherein linear movement of the float with the fluid level variation rotates the helicaid spring. Another object of the present invention is to develop a sensor to detect angular motion of the helicaid spring to determine the fluid level. Another main object of the present invention is to develop a method to detect fluid level, said method comprises steps of: guiding a float with a float guide and rotating a helicaid spring with linear movement of the float when the fluid level varies. Another object of the present invention is sensing the angular movement of the helicaid spring to detect the fluid level. Another main object of the present invention is to develop a method of assembling fuel level sensor comprising steps of: guiding a float with float guide and passing a helicaid spring through the float or through a magnet holder, wherein linear movement of the float with the fluid level variation rotates the helicaid spring. Another object of the present invention is placing a sensor onto the helicaid spring or on the magnet holder to detect angular motion of the helicaid spring to determine the fluid level. STATEMENT OF INVENTION Accordingly the invention provides for a fluid level sensor comprising: a float mounted onto a float guide with a helicaid spring, wherein linear movement of the float with the fluid level variation rotates the helicaid spring, and a sensor to detect angular motion of the helicaid spring to determine the fluid level; and there is also provide a method to detect fluid level, said method comprises steps of: guiding a float with a float guide, rotating a helicaid spring with linear movement of the float when the fluid level varies, and sensing the angular movement of the helicaid spring to detect the fluid level; and also a method of assembling fuel level sensor comprising steps of: guiding a float with float guide and passing a helicaid spring through the float or through a magnet holder, wherein linear movement of the float with the fluid level variation rotates the helicaid spring, and placing a sensor onto the helicaid spring or on the magnet holder to detect angular motion of the helicaid spring to determine the fluid level. BRIEF DESCRIPTION OF ACCOMPANIED DRAWINGS Figure 1 and figure 2 shows side view of the fluid level sensor Figure 3 shows perspective view of the fluid level sensor Figure 4 shows top view of the fluid level sensor Figure 5 shows cut view of the flange. DETAILED DESCRIPTION OF THE INVENTION The primary embodiment of the invention is a fluid level sensor comprising: a) a float mounted onto a float guide with a helicaid spring, wherein linear movement of the float with the fluid level variation rotates the helicaid spring, and b) a sensor to detect angular motion of the helicaid spring to determine the fluid level. In yet another embodiment of the present invention the float guide is pivoted between a flange and a base plate. In still another embodiment of the present invention a permanent magnet is placed on the flange side of the helicaid spring with a magnet holder. In still another embodiment of the present invention the sensor is Hall effect sensor mounted in the flange with a circuit board to detect the angular motion of the helicaid spring. In still another embodiment of the present invention the float's linear movement instantiates the magnet's rotary movement. In still another embodiment of the present invention the sensor remains stationary while the magnet moves along with helicaid spring movement. In still another embodiment of the present invention the flange has an integral electrical connector block for making electrical connections to the sensor. In still another embodiment of the present invention the magnet holder rotates with the helicaid spring's rotation. In still another embodiment of the present invention the helicaid spring rotates 180°. In still another embodiment of the present invention the helicaid spring passes through the float or through the magnet holder. Another main embodiment of the present invention is a method to detect fluid level, said method comprises steps of: a) guiding a float with a float guide, b) rotating a helicaid spring with linear movement of the float when the fluid level varies, and c) sensing the angular movement of the helicaid spring to detect the fluid level. In yet another embodiment of the present invention the helicaid spring rotates a permanent magnet mounted on it at flange side. In still another embodiment of the present invention sensing magnetic flux of the magnet using Hall effect sensor to detect the fluid level. In still another embodiment of the present invention is mounting the sensor in to the flange. Another main embodiment of the present invention a method of assembling fuel level sensor comprising steps of: a) guiding a float with float guide and passing a helicaid spring through the float or through a magnet holder, wherein linear movement of the float with the fluid level variation rotates the helicaid spring, and b) placing a sensor onto the helicaid spring or on the magnet holder to detect angular motion of the helicaid spring to determine the fluid level. In yet another embodiment of the present invention is pivoting the float guide between a flange and a base plate. In still another embodiment of the present invention is fixing a permanent magnet on the flange side of the helicaid spring with a magnet holder. In still another embodiment of the present invention a Hall effect sensor inside the flange to detect the angular motion of the helicaid spring. The present invention has been accomplished in view of the above problems. It is an object of the present invention to provide a liquid level detector with a reduced manufacturing cost. The conventional resistor card technology, commonly found in automotive applications for translating the position of the float into an electrical signal, is replaced by a non-contact magnetic flux sensing circuit. The fuel level sensor incorporates a magnetic flux sensor and magnet as in rotational position sensor configuration for determining the position of a float relative to its pivot base. In order to accomplish all the above objectives, the present invention adopts the following technical means. Referring to Figure 1 Fuel Level Sendor of present invention comprises, Base plate(7), U shaped float guide (3) in which the flange(2) is fixed at one end and base plate(7) at the other end, float(5), Helicaid spring (4) or Lever float (4) which guided the float (5) with its one end pivotally supported in base plate(7) other end is fixed in magnetic holder(8), magnet ho!der(8) which comprise magnet(l), PCB which contains linear ratio metric detecting element and wiring harness, cap (9). The movable member float(5) will move depends upon the liquid level in liquid tank and this instantiates the rotary motion of the Helicaid spring (4), magnet holder (8) and manget (1). Linear ratio metric detecting element which is called Hall element or Hall Effect sensor (6) remains stationary in PCB. The flange has SAE-5 Hole Bolt pattern, to mount the product in tank with Gasket which is also having SAE-5 Hole Bolt pattern (see figures 3 & 4). The SAE-5 hole (10) pattern is common to so many automotive and marine tanks. The Helical spring (4) rotates with linear motion as fluid level varies. The magnet (1) is placed inside the magnet holder (8) attached on the top of the helicaid spring (4). The magnet (1) rotates in which is placed below a Printed circuit board with Hall effect IC .The gap between magnet and the Hall IC in the PCB board should be necessarily be about 2.5 to 3MM and should be constantly maintained. On rotation of the magnet through the helical spring (4), due to the varying level of the fluid the magnet in the center rotates which creates a magnetic flux variation and due to this flux variation out put voltage is generated in the Hall IC and the same is taken as out put which is calibrated to the fuel level gauge accordingly. The preferred embodiment includes a magnetic flux sensor positioned in such a way to the rotating magnets. The magnetic flux sensing element is a Hall effect integrated circuit, with associated electronic circuitry having adjustable or programmable features including radiometry, gain, offset voltage, temperature coefficient, and output signal range limiting. Critical electronic components are hermetically sealed making the fuel level sensor fully submersible in fuel for long term fuel exposure. The electronic circuitry is designed to give genuine output from a resistor, voltmeter, capacitor etc. Fuel sensors according to the present invention facilitate improvements in vehicle cost The apparatus for sensing the level of fluid within a container is explained in much more detail. It comprises a lever type helicaid spring (4) coupled to the magnet at one end (a permanent magnet is used in this case), which in turn is supported between the flange and the base plate (7). A U shape float guide (3) members is pivoted between the flange and the base plate (7) with the helicaid spring (4) passing through the float (5). The float (5) is made as a movable member along the float guide (3) arm. The float (5) member moves relative to the base as the level of fluid in the container changes; the float (5) linear movement instantiates the magnet (1) rotary movement. The helicaid spring (4) guides or creates rotary movement of the magnet (1) based on the movement of the float (5) by rotating the magnet holder (8). Figure 4 clearly shows the arrangement of the magnet(l), holder (8) and the helicaid spring (4). It also comprises at least one magnetic flux sensor (Hall effect sensor 6) that is housed within a cavity containing encapsulated within the flange located within said container and is coupled to one of the electrical output signal in response to a change in magnetic flux density; At least one magnet disposed proximate the magnetic flux sensor coupled to lever type helicaid spring (4) for providing a magnetic field to induce a change in electrical output response from the magnetic flux sensor as the float (5) member moves linearly with changes in fluid level. The magnetic flux sensor remains stationary while the magnetic field changes position relative to the magnetic flux sensor. The flange has an integral mounting feature so that the fluid level sensor can be mounted to and positively located on a fuel tank module, other fuel system mounting feature or other mounting feature within a fluid container. The flange has integral features for positively positioning the magnetic flux sensor and the magnet (1). The flange has an integral electrical connector block for making electrical connections to the sensor electronics. The preferred amount of tilt or twist in the helicaid spring is about 180° when the bottom and top of it is compared. It is also helical in nature of twist as shown in the figure. There is another possibility that one can always have the same arrangement with minor changes. It is possible that the float (5) is fixed or mounted to the base of the helicaid spring (4) (i.e. at the base plate end). A path is provided in the magnet holder such that the helicaid spring will pass through it. The path could be something like the one provided in the float in the above embodiment. Thus when the fluid level varies it would move the float (5) linearly along the float guide (3). This would in turn move the helicaid spring linearly. This movement of the helicaid spring will create a rotary movement of the magnet holder (8). Now this rotary movement can be used to sense the level of the fluid. Probably we could the Hall effect sensor itself her to determine the fluid level. The fluid in discussion could be fuel, oil, water or any liquid. In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. We claim: 1. A fluid level sensor comprising: a) a float mounted onto a float guide with a helicaid spring, wherein linear movement of the float with the fluid level variation rotates the helicaid spring, and b) a sensor to detect angular motion of the helicaid spring to determine the fluid level. 2. The fluid level sensor as claimed in claim 1, wherein the float guide is pivoted between a flange and a base plate. 3. The fluid level sensor as claimed in claims 1 and 2, wherein a permanent magnet is placed on the flange side of the helicaid spring with a magnet holder. 4. The fluid level sensor as claimed in claims 1 and 2, wherein the sensor is Hall effect sensor mounted in the flange with a circuit board to detect the angular motion of the helicaid spring. 5. The fluid level sensor as claimed in claims 1 and 3, wherein the float's linear movement instantiates the magnet's rotary movement. 6. The fluid level sensor as claimed in claims I and 3, wherein the sensor remains stationary while the magnet moves along with helicaid spring movement. 7. The fluid level sensor as claimed in claims 1 and 2, wherein the flange has an integral electrical connector block for making electrical connections to the sensor. 8. The fluid level sensor as claimed in claim 3, wherein the magnet holder rotates with the helicaid spring's rotation. 9. The fluid level sensor as claimed in claim 1, wherein the helicaid spring rotates 180°. 10. The fluid level sensor as claimed in claim 1 or 3, wherein the helicaid spring passes through the float or through the magnet holder. 11. A method to detect fluid level, said method comprises steps of: a) guiding a float with a float guide, b) rotating a helicaid spring with linear movement of the float when the fluid level varies, and c) sensing the angular movement of the helicaid spring to detect the fluid level. 12. The method as claimed in claim 11, wherein the helicaid spring rotates a permanent magnet mounted on it at flange side. 13. The method as claimed in claims 11 and 12, wherein sensing magnetic flux of the magnet using Hall effect sensor to detect the fluid level. 14. The method as claimed in claims 11 and 12, wherein mounting the sensor in to the flange. 15. A method of assembling fuel level sensor comprising steps of: a) guiding a float with float guide and passing a helicaid spring through the float or through a magnet holder, wherein linear movement of the float with the fluid level variation rotates the helicaid spring, and b) placing a sensor onto the helicaid spring or on the magnet holder to detect angular motion of the helicaid spring to determine the fluid level. 16. The method as claimed in claim 15, wherein, pivoting the float guide between a flange and a base plate. 17. The method as claimed in claims 15 and 16, wherein fixing a permanent magnet on the flange side of the helicaid spring with a magnet holder. 18. The method as claimed in claims 15 and 16, wherein mounting a Hall effect sensor inside the flange to detect the angular motion of the helicaid spring. 19. A fluid level sensor, a method to detect fluid level and method of assembling as herein described in the description with examples and substantiated along with accompanied drawings.

Documents:

0702-che-2007-abstract.pdf

0702-che-2007-correspondnece-others.pdf

0702-che-2007-description(provisional).pdf

0702-che-2007-drawings.pdf

0702-che-2007-form 1.pdf

0702-che-2007-form 26.pdf

0702-che-2007-form 3.pdf

0702-che-2007-form 5.pdf

702-CHE-2007 AMENDED PAGES OF SPECIFICATION. 10-01-2013.pdf

702-CHE-2007 EXAMINATION REPORT REPLY RECEIVED 10-01-2013.pdf

702-CHE-2007 FORM-1 10-01-2013.pdf

702-CHE-2007 FORM-3 10-01-2013.pdf

702-CHE-2007 FORM.13 10-01-2013.pdf

702-CHE-2007 OTHER PATENT DOCUMENT 10-01-2013.pdf

702-CHE-2007 POWER OF ATTORNEY 10-01-2013.pdf

702-che-2007 abstract 09-11-2007.pdf

702-CHE-2007 AMENDED CLAIMS 10-01-2013.pdf

702-che-2007 claims 09-11-2007.pdf

702-che-2007 description (complete) 09-11-2007.pdf

702-che-2007 drawings 09-11-2007.pdf

702-che-2007 form-1 03-04-2009.pdf

702-che-2007 form-1 09-11-2007.pdf

702-che-2007 form-18 09-11-2007.pdf

702-CHE-2007 FORM-3 15-01-2010.pdf

702-che-2007 form-5 09-11-2007.pdf

702-che-2007 power of attorney 03-04-2009.pdf

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