Abstract: A reservoir tank includes a main portion and a storage chamber disposed in the main portion for storing operating fluid, with the storage chamber being surrounded by a side wall, a ceiling portion and a bottom portion. A float is disposed in the storage chamber and is adapted to move vertically corresponding to the height of the operating fluid level, and a reed switch is operatively associated with the float so as to operate in accordance with the height of the float. A partition member divides the storage chamber into an upper space and a lower space in which the operating fluid and the float are disposed.

Abstract: A system and method for measuring ampoule liquid level are presented. A buoy is arranged entirely within and detached from the ampoule. The buoy contains enough matter having a density less than that of the liquid to maintain flotation of the buoy, and has an exterior surface formed from a non-reactive material. The buoy is further designed to not interfere with any inlet or outlet structures of the ampoule. At least one magnet is displaced within the buoy such that the magnet is located near the ampoule's interior wall when the buoy is arranged within the ampoule. At least one sensor strip is located along the height of and entirely outside of the ampoule's interior wall, and at least one electronic sensor, containing at least one magnetically actuated switch, is located within each sensor strip. The electronic sensor may also contain a visible indicator and/or a resistor. The electronic sensor may be electronically connected to at least one separate system.

Abstract: A device for sensing the amount of oil in oil pans of internal combustion engines is disclosed. In the device, a bottom plunger is fixedly mounted onto the inside bottom of an oil pan, with a contact terminal being mounted onto the top surface of the bottom plunger. A top plunger is movably positioned above the bottom plunger, with a contact terminal being mounted onto the bottom surface of the top plunger. The two contact terminals are normally spaced apart from each other in the event of the amount of oil being not less than a preferred amount. However, the two terminals are selectively brought into contact with each other in the event of an oil shortage in the oil pan. The device also has a means for selectively generating an alarm signal under the control of an ECU in the event of the two terminals being brought into contact with each other.

Abstract: An alarm system to warn those pumping fuel into remote tanks that the fuel level is at the top of the tank, and thus prevent overflowing. This system is particularly useful for filling tanks in boats.

Abstract: A fluid level indicator for a brake fluid reservoir is disclosed which comprises a socket and circuit board which, once assembled, are installed within a chamber integrally molded with the fluid reservoir. The circuit board is assembled to the socket, which is in turn attached to an instrument panel warning device. In an alternative embodiment, the circuit board is formed integrally with connector pins, and injection molded about to form a socket assembly. The assembly is then attached to the instrument panel and installed within the chamber.

Abstract: In one embodiment of the present invention, a fluid level sensor includes a resistive element and a float coupled to a contact. The float moves in response to the fluid level, causing the contact to follow a path on the resistive element. The resistive element includes a layer of resistive material disposed on an insulating substrate. The resistive element also includes a layer of conductive material disposed on the layer of resistive material. The conductive material is disposed in segments along the path followed by the contact. This embodiment of the present invention provides a high-durability fluid level sensor which further provides low electrical noise.

Abstract: A method and apparatus for processing a photosensitive material. The apparatus includes at least one processing section and a replenishment system for delivering replenishment solution contained within a container to the processing section. The replenishment system including a single device for withdrawing replenishment solution from the container and for monitoring the level of the replenishment solution contained in the container. The container is made of a material that is electrically non-conductive. A pair of spaced electrically conductive members are provided within the container. One of the members has a passageway for allowing withdrawal of the replenishment solution from the container and has a terminal end which extends below the other member within the container. An AC current is applied to the pair of spaced members and the AC current is monitored with a level sensing circuit.

Abstract: A residential oil-fired furnace heating system includes an oil storage tank having a fuel level gauge, and a second fuel level indicator located in a zone remote from the fuel oil storage tank. The homeowner can read the oil level from the second indicator without having to go down into the basement or other area where the tank might be located. The second indicator can have an alarm device that is triggered when the indicator reading reaches the near-empty reading. The alarm device alerts the homeowner that it is time to reorder a new supply of fuel oil.

Abstract: A liquid level sensor device, particularly adapted for use with corrosive and hazardous liquids such as oil, for measuring the liquid level in a storage tank or vessel. A tubular device is placed vertically in a liquid storage tank and senses the liquid level by having a float embedded with magnets move vertically along the axis of reed switches encased in the tubular device. The device contains temperature sensors to measure the temperature of the tank fluid, and microprocessors that scan the reed switches, transmitting data through a connector in the device top to a nearby computer for recording and transmission to a control and monitoring location. The electrical data system inside the device utilizes only two conductive trace runs throughout the device length to maximize reliability while minimizing the copper used. Special mechanical and electrical assembly connectors inside the device permit the device to flex safely in turbulent liquid conditions, without breakage.

Abstract: The invention concerns a filling level measuring device composed of a nonmagnetic slide tube (7) containing a switch (8) driven magnetically in contactless manner and mounted on a plate (1) sealing a container aperture, further of a float (23) displaceably resting on the slide tube (7) and fitted with a first permanent magnet (24) actuating the switch (8). The float (23) of this invention further includes a second permanent magnet (25) a distance from the permanent magnet (24) associated to the switch (8), this second permanent magnet (25) resting by its own magnetic field on the magnetic field of an oppositely polarized permanent magnet (15) affixed to the slide tube (7). A magnetic coil (17) is affixed to the slide tube (7) which when energized generates a magnetic field reinforcing the effect of the oppositely polarized magnetic field and is of such field intensity that the float (23) is lifted into the switching position without being supported by buoyancy.

Abstract: A liquid level alarm system which activates an alarm when liquid in a container falls below a predetermined level. The system contains an alarm which is located outside of the container. The alarm is electrically connected to an activation device which is contained within a housing. A single-pull switch arm is connected to the activation device and protrudes from the housing. One end of a line is attached to the distal end of the arm. The other end of the line is wound about a spring reel mounted on an axle connected to a float. When the surface of the liquid is between a predetermined upper and lower level, the spring reel maintains the line taut directly below the switch arm. The line is of such length that should the liquid in the container drop below a predetermined level, the float will no longer be supported by the liquid, and the weight of the float will pull the arm down to activate the alarm.

Abstract: A highly reliable digital level sensor assembly is provided to replace optical and capacitance type sensors in high purity chemical delivery systems. The digital level sensor assembly is particularly useful in bulk chemical refill delivery systems for high purity chemicals employing a manifold that ensures contamination free operation and canister change outs with a minimum of valves and tubing.

Abstract: An apparatus is provided for detecting the level of a liquid in a tank. The apparatus is designed to be connected to a controller that controls a pump so as to switch the pump on when the liquid level reaches a maximum authorized level and to stop operation of the pump when the level of the liquid has gone back down to a minimum level. The apparatus includes a float that is lifted by the liquid and that is guided vertically. The apparatus also includes a magnet that is carried by the float, and at least two switches each having contacts sealed in a capsule. Each switch is fixed in a horizontal fashion to a plate so as to correspond to a predetermined liquid level, and each switch turns on an electrical circuit connected to the controller when the switch is in the magnetic field of the magnet. The plate is disposed in a vertical plane that is parallel to and in close proximity to the displacement of the float.

Abstract: A marine craft fuel alert system is operative during a given time period, to compare actual fuel capacity measurements with selected fuel tank capacity reference values, to permit timely intervention. Used with a relatively high reference value and operative during fuel loading, the system and methodology gives a warning to a fuel input agent (i.e., person controlling fuel loading) in sufficient time for the agent to terminate fuel loading and prevent environmental pollution by fuel overfill spillage. Conversely, the system and methodology, with appropriate modifications, can be used to sense and warn of predetermined low fuel level conditions. The system can be integrally incorporated into an original equipment marine craft system or retrofit thereto. Electrical interconnections may extend to marine craft ignition system interdiction during operation of the fuel loading monitoring and warning.

Abstract: A fuel recovery system warns a user of an impending overflow of fuel and also provides an overflow chamber into which relatively small amount of overfilled fuel are captured, thus preventing fuel spillage into the surrounding environment. The system is adapted for use with a fuel tank attached to a fuel fill line and an overflow line, and comprises a float assembly adapted to be coupled inline to the overflow line; an overflow chamber coupled via a check valve to the main fuel tank; and an optical/electronic warning system for warning the user when fuel in the float assembly rises to a predetermined level.

Abstract: A valve to monitor the level of fluid in an above ground storage tank while the tank is being filled, cutoff the flow of fluid when the tank is in a full condition, and as long as the filling pressure is on the valve the valve will remain cutoff even if the fluid level in the tank has lowered. A relief valve to drain the fluid remaining in the filling hose after the filling pressure is off. A sight level indicator to visually show that the tank is in a filled condition. A monitoring node to be used with or without the mechanical cutoff valve in a totally controlled application where the filling person is not responsible for shutting off the filling tank truck, with two switches, one to alert that the tank is near a filled condition and the second to alert that the tank is in a filled condition.

Abstract: The detector is a foldable one constructed of unit elements 1a-1n connected with each other through hinge members 6. The members 6 are staggered in arrangement along the longitudinal direction of the unfolded or stretched detector so as to permit the detector to be folded in staggered manner. In storage and transport, the detector is folded to facilitate its handling. In installation, the detector is unfolded or stretched to assume a long-reach form to facilitate its installation in a liquid-level gauge system of a storage tank 13.

Abstract: A highly reliable bulk chemical refill system for high purity chemicals is provided. The system employs at least one metallic level sensor in a refillable ampule. The refillable ampule of the present invention comprises a metallic level sensor for sensing a high level or full level in the ampule. The metallic level sensor transmits this signal to a control unit that automatically stops the refilling process. Additionally the refillable ampule includes a low level sensor that either provides an automatic signal for starting the refilling process or an audible or visual alarm to alert an operator that the container is empty and requires refilling. At the same time, the low level sensor sends a signal to the processing equipment indicating the empty state of the ampule.

Abstract: A water level detector and indicator system includes a water level detector and a water level display controlled by the water level detector to give a respective output signal when the level of water changes from one position to another. The water level detector can be a mechanical type which uses a float to control a multi-step switch causing a series of indicator lamps to give light respectively. The water level detector can be an electronic type which uses metal probes to detect the change of water level, and a controller driven by the metal probes to control buzzers and indicator lamps to work.

Abstract: A valve to monitor the level of fluid in an above ground storage tank while the tank is being filled, cutoff the flow of fluid when the tank is in a full condition, and as long as the filling pressure is on the valve the valve will remain cutoff even if the fluid level in the tank has lowered. A relief valve to drain the fluid remaining in the filling hose after the filling pressure is off. A sight level indicator to visually show that the tank is in a filled condition. A monitoring node to be used with or without the mechanical cutoff valve in a totally controlled application where the filling person is not responsible for shutting off the filling tank truck, with two switches, one to alert that the tank is near a filled condition and the second to alert that the tank is in a filled condition.

Abstract: An apparatus for detecting a liquid level includes a warning device for warning a low liquid level, and a regulator for controlling power supply to the warning device from a power source. The regulator comprises a switch for switching its condition in accordance with the liquid level. The ON condition of the switch indicates that the present liquid level is lower than a predetermined liquid level. The regulator further comprises a thermistor connected to the switch in series. The thermistor has a characteristic of decreasing the resistance value thereof, when a predetermined delay period of time as a function of atmospheric temperature has elapsed since the start of applying the voltage on the thermistor, synchronizing with turning the switch on. The low resistance value of the thermistor allows the power for activating the warning device to be supplied to its device, while the switch is turned on.

Abstract: A gauge assembly (10) utilizing a voltage divider circuit to provide reliable and accurate measurement of a fluid level within a tank (16) or other environment. A pointer assembly (52) pivots about an axis (42) in response to a moving float to indicate the fluid level. A plurality of contact arms (114, 116, 118) extending from a contact plate (58) on the pointer assembly (52) resiliently engage a point (120) along a resistive element (88). The first end of the resistive element is connected to a voltage regulator (100) which is connected to a first contact (94). The second end of the resistive element forms a second contact (96). The point (120) of contact between the contact arms and resistive element is connected to an amplifier (102) which is connected to a third contact (95) forming a low impedance voltage divider circuit.

Abstract: A funnel body includes an exit tube, wherein a mesh web pocket is arranged for securement to a lowermost end of the exit tube secured to an annular groove, with the pocket including a buoyant sphere arranged for projection into the exit tube exit opening for curtailing fluid flow therethrough.

Abstract: A dipstick for measuring oil levels provides an electronic indication when oil in an internal combustion engine sump is low or high. The electronic dipstick does not have to be removed as is normal for most dipsticks which determine level from observing a wet line on the stick. The dipstick has an elongated member for insertion into an aperture of a sump, the member has a high mark and a low mark thereon representing oil level in the sump. A float is mounted for movement within a cage integral with the elongated member, the float having a magnet to activate a switch. A first switch is associated with the high level and a second switch is associated with the low level. An indicating arrangement indicates when the magnet in the float activates either the first switch and/or the second switch.

Abstract: A float-operated switch assembly is mounted in an opening in the top of a tank. It includes a vertical non-magnetic pipe having a pair of floats normally hanging beside it. Each of the floats has a magnet thereon normally in a position proximate the pipe when the float is down. A magnetic field between this magnet and a switch operator support magnet inside the pipe normally holds the latter magnet in a set position. The floats are located at a height such that, when the liquid has risen to the desired upper limit, the rising liquid has caused the floats to swing up and outward from the pipe, pulling their respective magnets out of supporting relationship to the switch operator support magnet whereupon the support magnet drops and a switch is operated for activating a signal circuit. A manual test knob is provided to remotely, manually lift the floats.

Abstract: A fluid level responsive switch apparatus used in a tank to monitor fluid level in the tank. The apparatus has a float buoy attached to a tilt switch containing three conductors activated by a conductive sphere. The first conductor activates the fluid controller for restoring fluid to the tank when the conductive sphere is in a low fluid level position, the second conductor delays the switching between the activating and deactivating conductors when the conductive sphere is in an intermediate level position and the third conductor deactivates the controller when the conductive sphere is in a high fluid level position.

Abstract: A system for precisely measuring the amount of oil consumed during operation of an internal combustion engine includes a float chamber which communicates with an oil sump in the engine. A float is disposed within the chamber which moves upwardly and downwardly therein, depending upon the level of oil. A precision level detector is mounted in the upper end of the chamber for generating an electrical signal which is representative of the position of the float within the chamber. A microprocessor receives this signal, along with signals from various other sensors representing engine speed, engine torque, and oil temperature. In response thereto, the microprocessor controls the operation of a pump connected between an external supply of oil and the engine sump. When predetermined conditions are met, the microprocessor activates the pump to add oil from the system. The microprocessor also records the oil level over a period of time to determine the rate of oil consumption.

Abstract: A low salt level sensor comprising a float within a brine tank, apparatus for detecting whether the float has risen in response to the addition of a predetermined amount of water to the brine tank to a height such that an adequate supply of salt is present in said brine tank and apparatus for indicating if the float has not risen high enough. A method of detecting whether the salt level is low in the brine tank of a water treatment system is also described. According to this method, brine is removed from the brine tank and a predetermined amount of water is added. A determination is then made as to whether the brine level has reached a height such that an adequate supply of salt is present in the brine tank and an indication is provided if the brine level is below this height.

Abstract: A circuit including a sender providing a sender output signal responsive to a vehicle parameter, circuitry for providing an adjustable reference, circuitry for comparing the output signal to the adjustable reference and providing a comparison output signal therefrom, an up/down counter for filtering the comparison output signal, and circuitry for providing an indicator control signal in response to the filtered output signal and for controlling the adjustment of the adjustable reference, provides a signal to a vehicle operator that is both filtered and has hysteresis to minimize repeated switching of the signal between two states.

Abstract: A fail-safe system for the detection of water leaks, and for the prevention of damage therefrom. In a home or building which includes a hot-water tank and a water tank for a toilet, e.g., the damage-prevention system comprises valves for shutting off the supply of water to the tanks, and other valves for draining the tanks through discharge lines to the outside of the home or building. At the same time, power to the hot-water tank is shut off. A fail-safe water detector comprises a float with a metal cap, a first pair of electrical probes below the float, and a second pair of electrical probes above the metal cap and separated from the cap by an air gap. A circuit is closed in any of three ways: (1) when water contacts the first pair of probes, (2) when water raises the float and makes contact between the metal cap and the second pair of probes, and (3) when water contacts the second pair of probes.

Abstract: A gauge for indicating whether the level of a liquid, such as fuel or oil, in a tank has reached one or more preselected levels. A magnet is mounted in a stem attached atop a float which moves up and down with the rising and falling of the liquid level. When the magnet is adjacent an electrical switch housed in a sealed cover, the switch closes and connects an external power supply to a warning light. The float moves within a cylinder which has a small drain hole at the bottom and a vent near the top. Liquid moves into and out of the guide through the drain hole at a relatively slow rate and thereby eliminates intermittent closing and opening of the switch which would otherwise occur due to the sloshing of the liquid when the tank is in motion, such as when mounted in a vehicle.

Abstract: A liquid level detector in which a float is operatively connected to the core of a linear variable displacement transformer. Output signals from the transformer are amplified, sampled, and averaged to obtain an indication of changes in liquid level. As an important feature of the invention, a cyclic disturbance mechanism is oriented to jostle or disturb the float or a motion-transmitting member connected to the float. The jostling force frees the float from frictional forces that would otherwise tend to prevent the float from reaching a true equilibrium position relative to the liquid surface. The float tends to continuously cycle back and forth, hunting a true equilibrium position. By sampling the float position a large number of times, such as one hundred times, an averaged signal representing the true equilibrium position of the float is obtained.

Abstract: A float actuated resistive oil level display with warning for providing continuous visual indication of oil level in the oil pan of an internal combustion engine. The system includes a reservoir which communicates with the oil pan such that the oil level in the reservoir corresponds to that in the oil pan. A selectively designed float resistor is disposed within the reservoir in such a manner as to compensate for the quantity of oil distributed throughout an engine's lubricating system while it is running, and is part of an electrical circuit which includes a meter and an alarm circuit remotely positioned within the view of the operator of the motor vehicle or other device powered by the engine to provide a continuous visual indication of oil level in the oil pan, even while such motor vehicle or other device is being operated.

Abstract: A liquid level and temperature sensing device for monitoring and measuring the level of liquid stored within a tank or reservoir comprising control circuitry to generate and transmit digital level interrogation pulses and a transducer to receive sonic level return signals corresponding to the digital level interrogation pulses and generate corresponding digital level signals and logic circuitry to measure the time lapse between corresponding digital level interrogation pulses and the corresponding digital level signals and a lower sensing probe including an inner conductor coupled to the control circuity to receive the digital level interrogation pulses and a float to float on the liquid within the tank or reservoir including a magnet movable tube to interact with the electromagnetic field generated in the inner conductor by the digital level interrogation pulses to generate the corresponding sonic level return pulses transmitted to the transducer to generate the corresponding digital level signal whereby the

Abstract: The invention is an improved level indicating and elevation indicating system using a hose containing fluid having a first and a second end, capable of being operated by a single person. An electronic method is used to indicate when a float at the first end of the hose is at, above, or below a reference. In the preferred embodiment, such indications are communicated through wires to three distinct lights at the second end of the hose, and a sight is used to determine accurately the position of a float at the second end. The preferred embodiment also includes a sleeve supporting the first end of the hose and a support for the sleeve. Also included are a vertical fixed rod for supporting the second end of the hose, a base for holding the fixed rod in virtually any position, and an adjustable rod (parallel to the fixed rod) for determining vertical offset distances. A pinching device, for slightly varying the volume of the hose, is also part of the preferred embodiment.

Abstract: A fluid level detector comprises a tank including a sleeve portion extending vertically from a bottom section of the tank to a top section of the tank, and sensor device mounted to a circuit board connected at one end to monitoring device, with the circuit board being inserted into the sleeve. There is a circular float assembly with a center aperture. The circular float assembly includes a pair of magnets mounted in push-pull orientation at opposite sides of the aperture within the float assembly. The float assembly is slidably positioned over the sleeve whereby the float assembly moves up and down the sleeve as the water level changes in the tank, wherein the sensor device generate a signal representing detection of fluid level by the sensor device when the fluid level in the tank is substantially at the level of the sensor device.

Abstract: A remote indicator attachment kit for use with the mechanical level gauge of an oil tank located in the basement area of a dwelling, to indicate at a remote point the drop in oil level, comprises a magnet attachable to the movable member of the existing mechanical gauge, and a reed switch and mounting that is attachable to the see-through housing of the mechanical gauge, to be influenced by the magnet on the movable member. Circuitry connected to the reed switch and to the remote indicator is energized to provide an indication at the remote point.

Abstract: The invention is directed to a liquid level sensing device having a float (4) configured as a hollow body and slidably mounted on a slide tube (3) for the actuation of reed-type switches (11) provided in the interior of the slide tube (3). In order to perform a check for proper functioning, the float (4) is movable independently of the filling level into a signalling position by an electromagnetic actuation device (15). The hollow space (7) of the float (4) contains a gas pressurized to above or below atmospheric and is connected via a flexible tube (12) to a pressure monitoring device (13) which responds whenever the gas pressure deviates from a predetermined value.

Abstract: A material level sensing device for detecting when the level of unprocessed material has reached a predetermined threshold includes a contact-type probe extending from a housing into a retaining bowl where unprocessed material is collected before processing. Within the housing is disposed a proximity sensor. The housing itself is suspended from an overhanging support. When the material level reaches the predetermined threshold, the material displaces the material level sensor, which displacement is sensed by the proximity sensor. The proximity sensor then sends a signal to an external system indicating that the material has reached the threshold.

Abstract: A gauge (10) is disclosed which provides advantages in accuracy and cost. A head (16) is mounted on a reservoir containing a fluid to be monitored. A cylindrical support tube (28) is secured to the head and extends into the fluid. A head bushing (40) and a bottom bushing (42) are secured at opposite ends of the tube (28) and support a helically twisted center shaft (48) for rotation about an axis. The center shaft passes through a float (60) which is guided for movement along the axis by guide ribs (34, 36) on the support tube.

Abstract: The improved device for measuring liquid-level changes in storage tanks uses a float to track vertical displacement of the surface of a liquid and a linear variable differential transducer (LVDT) sensor positioned below the surface of the liquid to measure changes in the surface level. The center of gravity of the device is located below the center of buoyancy, thereby minimizing instability of the LVDT sensor.

Abstract: The gauge has an outer tube sealed at its lower end and adapted for attachment to the top wall of the tank, and an inner tube axially movable within the outer tube. A float encircles the outer tube and moves freely therealong. First and second magnets respectively attached to the float and to the lower end of the inner tube provide magnetic coupling therebetween so that a rising liquid causes the inner tube to rise with the float. Magnets within the inner tube operate a switch to signal when the first and second magnets are in position for magnetic coupling therebetween. Another magnet is fixed by a set screw to the outside of the inner tube in position for operating the switch when the tank is substantially full. Retaining clips are also disclosed for holding the latter magnet in place.

Abstract: A method and apparatus for measuring low fuel level in a fuel tank having a fuel pump with an anti-slosh pot supplied with fuel from a predelivery pump in the fuel pump. Fuel measurement is effected by sensing delivery of air to the anti-slosh put by the predelivery pump when the fuel level in the tank is low, and measuring the amount of fuel in the anti-slosh pot when delivery of air is sensed. The amount of fuel measured in the anti-slosh pot accurately represents the amount of fuel remaining in the fuel tank.

Abstract: A polymeric insert is arranged for securement within a base portion of a water cooler housing to accommodate drainage from a water cooler top wall. Drainage and condensation is accommodated to minimize corrosion of a lower portion of the water cooler housing. A modification of the structure includes a fungicide and herbicide distribution reservoir and an alarm indicating stoppage of the associated drain structure of the organization.

Abstract: A sphere-actuated float switch is provided including (i) a cage defining a longitudinal raceway, (ii) a yoke pivotally mounted externally to the cage and having a first and second legs which extend into the raceway, (iii) an electrical switching means which is electrically open when the yoke is in a first position and electrical closed when the yoke is in a second position, (iii) an over-center spring capable of biasing the yoke into the appropriate electrically open and the electrically closed positions once the yoke is urged past a transition point, and (iv) a sphere within the raceway for urging the yoke between the electrically open and the electrically closed positions.

Abstract: This invention concerns a water alarm adapted to be mounted in a basement water drain. It comprises a buoyant body which is in a first position when water is absent from the drain and which is moved to a second position by the presence of sufficient water filling the drain pipe. The buoyant body carries a switch which is in an open position when the body is in its first position and which is in a closed position when the body is in its second position. A suitable alarm is activated when the switch is in its closed position. The buoyant body is held in position adjacent the upper end of the drain under the metal drain cover by a magnetic holder member.

Abstract: Corrosion of the fuel tank float device by electrolysis is minimized by driving the fuel level sender with short duty cycle pulses instead of a continuous current. While the fuel level sender is energized by a pulse, the analog sample and hold circuit obtains a reading from which fuel level can be determined. A synchronizing circuit controls the sequence in which the fuel level sender is energized and the reading taken, to insure that readings are taken during steady state conditions. An impedance matching circuit compensates for nonlinearities of the fuel level gauge. The impedance matching circuit includes a pair of precision resistors and a voltage multiplier circuit. The impedance matching circuit allows the moving coil fuel level gauge to be energized in a fashion which simulates a continuous current flowing between fuel level sender and gauge.

Abstract: A self-aligning oil level sensing switch is provided with an elongated float shaped to pass freely through a threaded aperture in the side of an engine crankcase as a switch housing is screwed into the aperture. The float is free to rotate about one end of a mounting rod, and is unsymmetrical about its center of mass such that it is automatically aligned by gravity into its intended operating position, regardless of the final rotative position of the switch housing. The mounting rod is pivotally and rotatably mounted on the switch housing and has an opposite end provided with a counterweight which is unsymmetrical and is free to rotate with the rod. A magnetically actuated switch mechanism includes a spring-biased magnet enclosed in a conductive sleeve which is electrically coupled to a first connector pin. The sleeve is positioned within an electrically-conductive, magnetically-transparent cover member electrically coupled to a second connector pin.

Abstract: An oil level sensing apparatus has a body which defines a volume having an open bottom. A float in the volume supports a permanent magnet and moves within the volume in accordance with the oil level therein. A reed-switch is affected by the magnet supported on the float to detect a low oil level. A temperature sensitive plate closes the open bottom of the volume at low temperatures in order to prevent false readings. Additionally, in order to prevent false readings during transient oil level fluctuations at higher oil temperatures, a spring opposes the opening of the plate such that a restriction is formed in the path for draining oil from the volume. This delays the oil drainage from the chamber and any resulting low oil level signal.

Abstract: A hollow float bulb or shell is secured to a flexible electrical cord and encloses a housing which confines an electrical switch and defines a chamber with an inwardly projecting barrier. A weight member in the form of a metal ball is disposed within the chamber and rolls over the barrier to actuate the switch in response to tilting movement of the shell and housing. In one embodiment, a shuttle in the form of a metal frame is supported within the chamber for sliding movement and carries a switch conductor element. The shuttle frame is impacted by the ball located within the frame when the ball rolls over the barrier, and the frame is restrained by magnets to produce snap actuation of the switch.