Abstract: A speed sensor device incorporates a reed switch which is controlled by the changes in the density of the magnetic flux in response to the displacement of a permanent magnet. The device comprises at least one permanent magnet positioned on a rotational shaft, a reed switch opened and closed in response to the rotational displacement of the permanent magnet, an elastic member protecting the periphery of the reed switch, a body member being made of a material having excellent electric conduction and receiving the reed switch, a supporter being in a thin plate form and also being made of a material having excellent electric conduction, and a projection formed on the supporter serving to secure the supporter to the body member.

Abstract: A reservoir is disclosed which has a tank made of synthetic resin and incorporated a liquid level sensing device whereby the sensing device has a magnetically actuable switch enclosed in a depending hollow tubular portion of the tank and a float having a magnet which is axially slidable on the tubular portion in order to actuate the switch when the magnet and the switch are in proximity with the tank having both upper and lower shells with the upper shell being formed integrally with the hollow tubular portion and one of the shells being formed integrally with a heat shielding skirt portion which surrounds the tubular portion. The heat shielding portion extends into the interior of the lower shell for shielding the tubular portion against the welding heat during the connection of the upper and lower shells.

Abstract: An apparatus comprising a float vertically movable in a case, a driven member fitting to the float and having a movable attracting portion, upper and lower fixed attracting members disposed above and below the portion in opposed relation thereto, a stopper provided at a lower portion of the driven member for supporting the load of the float, a reed switch magnetically operable by the approach or retreat of the movable portion, and a contactless switching element consisting essentially of a TRIAC and operable by the reed switch. The reed switch is instantaneously opened or closed and held opened or closed when water level reaches an upper limit or lower limit. The apparatus is useful for automatically controlling underwater pumps.

Abstract: An easily calibrated indicating device for monitoring pressures or other parameters that vary, comprising a housing having a scale plate with indicia representing a range of values, and an indicating member movable over the scale plate, for designating various values thereon. A driving permanent magnet is movable in the housing, and responds to changes in the parameter being measured. A movable follower permanent magnet is also provided in the housing, for reacting with the driving magnet, the follower magnet in turn being connected to the indicating member so as to shift the same in response to movement of the driving magnet. A third, trim or calibration permanent magnet is provided, which alters the reaction between the first two magnets, thereby enabling either an expansion or else a contraction of the range of movement of the indicator member to be had as it responds to a predetermined change in the condition being measured.

Abstract: A fluid level sensitive switching device is disclosed that utilizes a lost motion type action to increase the available fluid drawdown and cycle level of the switching device.

Abstract: In a switch device having a reed switch activated by a magnet carried by a first float, the differential between the reed switch being activated and de-activated is increased by providing a second float vertically spaced from the first float and arranged to hold the latter against switch de-activating movement when the liquid level changes and until the liquid level is such that the level of the second float changes to a predetermined level.

Abstract: A liquid level registering device in a tank of liquid includes a non-magnetic tube surrounded by a movable magnetic float. The tube contains a dielectric oil and reed switches which are fixed at different levels. When the level of liquid carries the magnetic float to the same vertical level as a particular switch, that switch changes its state.

Abstract: The invention relates to a device for articulating a moving blade pivoting on its base.The mobile member is constituted by a blade fixed to a float, which floats on a liquid contained in a cavity made in a base, the liquid being kept in the cavity by capillarity. The nature and dimensions of the float are adapted to the liquid density. The cavity dimensions are large enough to permit the float to move, without mechanical jamming. The mobile assembly, blade and float is prevented from escaping from the cavity by at least one bridge welded to the base towards the ends of the float.Application to switches with blades wetted by an electricity-conducting liquid.

Abstract: Apparatus for warning of the increase in draught of a floating article, especially a small boat, in a surrounding liquid. The apparatus includes a signal emitter and a source of current which are connected, via a relay and a switch, to a release unit. The release unit includes a chamber fixedly arranged relative to the article which communicates with the surrounding liquid. The chamber holds a contact device which is adapted to close an electrical circuit when the liquid has risen to a certain level in the chamber.

Abstract: A fluid level detector comprising a cylindrical member which includes a mounting portion fitting in the opening of a fluid reservoir and a float guide portion extending downwardly from the mounting portion. A float, provided with a magnet, is slidably fitted over the float guide portion. A lead switch is disposed in the float guide portion. A terminal is connected to the lead switch via a lead 18. A lid member is mounted to close the opening of the reservoir. A terminal holder is integrally formed on the cylindrical member. The lid member includes an upper cover covering the upper portions of the mounting portion and the cylindrical member, and a lower cover. In assembly, after interposing the terminal holder between the upper and lower covers, the cylindrical member and the lid member are mounted to the reservoir as a unit.

Abstract: An hydraulic switch (10) and method for controlling the starting and stopping of a pump is disclosed. Switch (10) has an aperture (34) in the base (32) of a reservoir (28). Liquid enters aperture (34) thereby raising float (38) which operates switching mechanism (26) to start pump motor (20). As liquid is pumped passed impeller (22) along flow path A, some of the liquid is forced into conduit (36) leading to reservoir (28). The liquid flowing through conduit (36) keeps reservoir (28) filled. Consequently, float (38) remains in an elevated position keeping switch mechanism (26) on. Float (38) does not descend until liquid ceases to be pumped and stops flowing through conduit (36). Then, as liquid drains from reservoir (28) through aperture (34), float (38) drops thereby causing switching mechanism (26) to switch motor (20) off.

Abstract: A float operated electrical switch assembly has a housing (10) fitted to an opening in a container wall (14). A float (19) follows the liquid level and is pivoted with a primary magnet (18) about a pivot axis (17). A pivotal secondary magnet (21) acts in repulsion with the primary magnet (18) through a non-magnetic wall (20) of the housing (10). The movement of the secondary magnet (21) causes at least one control rod (48) to reciprocate. A switch contact (32) is normally held under the resilience of its carrier leaf spring (38) in engagement with a fixed switch contact (33). The contacts are opened by movement of the control rod (48) moving the switch contact (32) against the resilience of its carrier.

Abstract: A low liquid level float control apparatus particularly adapted for use in vessels or tanks containing a fluid of the type utilized in liquid vending machines is disclosed. An electronic control unit has a probe section extending downwardly therefrom containing a reed switch, which is activated by the passage of an annular magnet vertically along the probe section. A second magnet is secured about the lower most portion of the probe section and is adjustable along the probe section thereby increasing the switch delay time, thus reducing the possibility of intermittent on-off operation of associated pump elements.

Abstract: A fiber optics level sensor (FOLS) or flow sensor (FOFS) system for use in hazardous environments, process control, and industrial and environmental control applications. The system includes a pair of fiber optic bundles arranged between a remote sensor and a control module. The remote sensor detects the position of a movable vane--which is mechanically coupled to a float in the sensed environment--by means of a transmission gap between confronting ends of the pair of fiber optic bundles. The control module includes a light output device driven by an oscillator which thereby generates pulses of light which are optically coupled to the end of one of the bundles. The end of the other bundle is coupled to a photodetector which generates electrical pulses in response to the returning light pulses. The electrical pulses are amplified and then gated through a sampling circuit which is internally synchronized by means of and in resonse to the oscillator.

Abstract: A liquid level detecting and warning device of the kind including a tubular member having a mounting portion fitted on an opening of a reservoir and a float guiding portion downwardly extending from the mounting portion, a float having a magnet and slidably fitted around the float guiding portion, a reed switch disposed within the float guiding portion, terminals connected to the reed switch through lead wires, and a cover member covering the opening of the reservoir and the mounting portion of the tubular member. The tubular member is formed to have at least two projection radially outwardly projecting from the upper end portion thereof.

Abstract: The level detecting device comprises a detector inserted in a reservoir to detect the level of oil liquid, lead wires leading signal from the detector, and a terminal connected to the lead wires. The terminal is fixed to a cap covering an opening of the reservoir and the cap is removably engaged to a cylindrical projection arranged around the opening of the reservoir.

Abstract: A magnetic sensing device for sensing the proximity of a gas lift plunger up from the bottom of an oil or gas producing well is used to initiate the off cycle of the well and which comprises only one moving component, a magnet which is attracted to the plunger, completing an electrical circuit to a unit for controlling the operation of the well. The magnet is returned to its resting position by a ferrous set screw adjacent the magnet which attracts the magnet once the gas lift plunger has passed the field of the magnet sensor. The magnet and electrical contacts for the sensing device are enclosed in a molded plastic housing which can be easily opened to repair or replace any worn components.

Abstract: The present invention provides an improvement by adaptation of a rising stem fuel oil gauge for indicating, at a remote location, the quantity of fuel in oil storage tanks commonly used in homes and businesses. The improvement includes a magnet carried on a horizontally positioned level indicating disc, which is attached to the upper end of a vertically rising stem and enclosed within a transparent tube. Markings on the tube correspond to the quantity of fuel oil within the storage tank and the alignment of the indicating disc with a specific marking indicates the fuel oil quantity at any given time. A magnetically actuated reed switch is mounted to the exterior of the tube at a predetermined position, and a power supply and remote alarm are coupled to the switch. When the level of the indicating disc is near the position at which the switch is mounted, the magnet carried on the disc actuates the switch which in turn actuates the remote alarm.

Abstract: A liquid level responsive proximity switch for submersible sump and sewage pumps in which a magnetic float, normally buoyed on mercury or other conductive liquid, is submerged by a movable magnetic actuator to displace the mercury into contact with a pair of switch electrodes. The mercury, magnetic float and electrode assembly are housed in permanently sealed casing having a downwardly opened chamber for the actuator under the magnetic float.

Abstract: A fluid-level detector comprises a container, here a brake-fluid reservoir for an automotive vehicle, adapted to hold a supply of a fluid and containing a float connected via a link arm to a permanent magnet for displacement of the magnet vertically through a predetermined magnet position on vertical displacement of the float through a predetermined float position corresponding to a fluid level at which a signal is to be given. A pair of contacts outside the container can be engaged by a switch element which is displaceable toggle-fashion by the magnet between a closed position engaging and forming a closed circuit with the contacts and an open position out of engagement with at least one of the contacts.

Abstract: Liquid level in tanks is gauged an can be controlled as follows. Liquid communication is provided from near the bottom of the tank to a liquid reservoir containing a liquid which is of different density and immiscible with the tank liquid. The reservoir is in liquid communication with a vertically elongated vessel having a relatively small horizontal area compared to the tank, communication being near the top of the reservoir if the reservoir liquid is less dense than the tank liquid and being near the bottom of the reservoir if the reservoir liquid is more dense than the tank liquid. The elongated vessel, which can be transparent or translucent so that the liquid level therein corresponding to the liquid level in the tank can be readily determined, can contain a float containing a proximity sensor triggering element.

Abstract: The housing of a reed switch, actuatable by magnetic flux, is supported at the ends by grommets fitting snugly inside an aluminum sleeve. The switch terminals extend from the housing adjacent a closed end of the sleeve, have lead wires soldered to them and are in an embedment of silicone rubber. A cable having electric lines projects into an open end of the sleeve. After passing through an insulating spacer plate the wires are soldered to the cable lines. The portion of the sleeve between the open end and the adjacent grommet is filled with a silicone rubber embedment. The sleeve is positioned in a bore in a mounting body and adjacent a side of the body is a float responsive magnet.

Abstract: In the gas shortage detection device of a piston-type hydropneumatic accumulator, a control rod slidably mounted in the cylinder head on the gas side is displaced under the action of the thrust exerted by the piston when this latter comes closer to the cylinder head than a predetermined distance. A flexible motion-reversal coupling element such as an inextensible cord which works in traction and has a predetermined dead range of travel is placed between the piston and the sliding rod.Correct performance of the detection device can thus be checked by partial draining of the oil compartment, the detection device being triggered into operation when the piston comes close to the bottom end of the cylinder.

Abstract: Apparatus for ascertaining the upper level of oil or another liquid in a shallow or deep tank has a perforated vertical conduit which is installed in and extends to the bottom of the vessel. A vertical pipe is adjacent to the conduit and is sealed from the contents of the tank. The pipe contains electrical components which are connected to an indicating instrument and include a row of spaced-apart electric switches actuatable by a permanent magnet in a float which is movable up and down within the confines of the conduit so that the instrument receives signals denoting the actuated switch or switches and thus enables an attendant to ascertain the liquid level in the tank. The pipe and the conduit consist of several superimposed sections having flanges which are bolted or otherwise separably connected to each other to allow for convenient dismantling of the pipe and conduit and their transfer to storage or to another tank.

Abstract: Liquid level sensing means comprising galvano-magneto effect transducing means, magnet means for applying magnetic flux to the transducing means, switching means movable with respect to the transducing means and having an influence on the magnetic flux applied from the magnetic means to the transducing means so that an electric signal is produced by the transducing means when the switching means has passed by the transducing means from one side to the other side thereof, one of the transducing means and the switching means being held stationary, and the other being movable in accordance with a change in liquid level.

Abstract: An upright metallic pipe, which extends into the supply of liquid in a vessel adjacent to a conduit for a float with a permanent magnet which rises and falls with the upper level of liquid, contains an elongated flexible body having an impermeable insulating sheath and an insulating web in the sheath. The web carries a row of electric resistors and an adjacent row of electric switches which are connected with a level indicating instrument. The switches are actuated by the magnet to thereby change the number of resistors which are connected with the instrument. The flexible body can be withdrawn from the pipe and converted into a small package consisting of overlapping convolutions. Such conversion involves flexing the web in the regions between neighboring switches. Such regions are traversed by flexible conductors which connect the neighboring switches and/or resistors to each other.

Abstract: A device capable of sensing forces exerted by fluids, particularly liquids, and thus may be used to sense fluid level and fluid flow. Preferred embodiments of the device include a switch means capable of being actuated without the exertion of substantial mechanical force thereon and an elongated body of low mass mounted for pivotal movement about an end thereof with switch actuation means at an end thereof in operative relation to the switch means only when the axis of elongation of the body is aligned with the switch means. Features of the device provide reduced inertial effects and reduced gravitational force requirements, as well as reduced wear, in operation.

Abstract: A deenergized solenoid operated valve normally closes the drain line of a sink, basin, tub or toilet bowl, the valve thus serving as a stopper. When a pushbutton switch is closed, the solenoid is energized to retract the valve and open the drain, a flow responsive switch maintaining the solenoid energized until all of the water has drained from the sink or bowl. A float responsive switch will also energize the solenoid to retract the valve and open the drain if water accumulates from a leaky faucet. Whenever water is drained, the low pressure or vacuum that results produces an accompanying venting action. The invention may be used with a P or S-type drain connection and/or with a conventional stack vent, but does not require that any of these be employed.

Abstract: An apparatus for monitoring and controlling the liquid level in a storage tank which involves placing at least two magnetically operated switches, e.g., magnetic-reed switches, at different levels in the tank and causing a magnet-containing float to move in response to the liquid level to activate these switches. A relay operates upon activation of the higher of these switches to start electrical current flowing to operate a discharge pump, thereby controlling the liquid level in the tank. In a preferred embodiment, a third magnetically operated switch is employed so that when the magnet activates the third switch at least one indication, e.g., sound and/or light alarm, is given that the liquid level is at least at a predetermined level.

Abstract: A differential float control is provided by a single switch and a single float wherein a vertical guide tube contains a magnetically operated switch, and a free float surrounds the tube and rises and falls with the liquid level and carries two magnets. As the float moves in one direction the switch is magnetically latched closed by one magnet and remains closed until unlatched by the other magnet as the float returns in the opposite direction. The switch may be normally open, or normally closed, so that movement of the float may provide any desired circuit sequence for operating a liquid level controlling pump or the like for maintaining the liquid level within prescribed limits.

Abstract: A miniature contactless switching unit is disclosed for use in various kinds of position sensors with a magneto-electro converter. The miniature contactless switching unit includes a molded block case in which a permanent magnet and the magneto-electro converter are oppositely disposed, and a screening member for screening magnetism, which operates in accordance with the movement of a moving member, whereby when the moving member is in a first position, the screening member is not disposed between the magnet and the magneto-electro converter to hold the output of the converter in a first switching state, while when the moving member is in a second position, the screening member is disposed between the magnet and the converter so as to prevent the magnetic flux from said magnet to the converter to hold the output of the converter in a second switching state.

Abstract: The invention contemplates remotely operable lifting mechanism for selectively displacing a liquid-level float in a sealed tank, to permit checking of the operational status of the float throughout its displaceable range, and to permit check-out of magnetically operated electrical means actuated by the float at a predetermined float level within its displaceable range. The lifting force is coupled magnetically to the float without interference with the path of float movement and without interference with the magnetically operated electrical means.

Abstract: A magnetic detection device for detecting the position of a movable member which is associated with a piece of magnetic material, the movable member being displaceable in a non-magnetic tube. A detection unit fixed outside the tube and including a permanent magnet with pole pieces directed towards the tube and extended portions extending away from the tube. The extended portions may be either in a plane parallel to or perpendicular to the axis of the tube. A dry reed relay is fixed relative to the pole piece with its ends facing the extended portions remote from the magnet. The extended portions may extend from opposite sides of the tube in which case the extended portions are perpendicular to the axis of the tube and the axis of the reed relay has a normal parallel to the axis of the tube. Alternatively, the reed relay is disposed parallel to the axis of the tube in which case the pole pieces are disposed on the same side of the tube.

Abstract: A radiator cap composed of a cap body, a compression gasket assembly connected to the cap body and adapted to open and close in accordance with the pressure of the coolant in the radiator, a float engaged with the cap body so as to move up and down in accordance with the level of the coolant. The upper edge of the float is formed so that upon contact with a gasket assembly, a valve is formed with said gasket assembly. A reed switch secured to the cap body is opened or closed in response to movement of the float so that the reed switch actuates suitable warning means when the level of coolant falls over a predetermined line.

Abstract: A brake fluid reservoir includes a main body portion having a cap securing a diaphragm between the body and the cap. A sensor is mounted to protrude into the reservoir for indicating a predetermined minimum level of brake fluid in the reservoir. The diaphragm is provided for corresponding movement in response to decreases in the level of brake fluid in the reservoir and also for separating a brake fluid containing portion of the reservoir from an air containing portion. The diaphragm includes an interstice for permitting air in the air containing portion to be drawn into the fluid containing portion under preselected conditions. A protective device surrounds the sensor for maintaining the movement of the diaphragm from interfering engagement with the sensor. The brake fluid reservoir may be used in a vehicle brake system including a master cylinder connected for fluid communication with the reservoir and with the front and rear brakes of the vehicle.

Abstract: A fluid bilevel sensor containing a differential float and a magnetically actuatable switch generating an electrical signal upon the occurrence of one fluid level. A thermal time delay delays the application of the electrical signal to a load for a predetermined time. The magnetically actuatable switch removes the electrical signal upon the occurrence of a second fluid level. The thermal time delay delays the removal of the electrical signal from the load for a predetermined time.

Abstract: A sewer back-up alarm unit. It replaces the plug in an access opening. And, it has a solid wall with a short pivoted arm mounted on the inside of the wall. The arm is angled and pivots freely between two positions, as limited by the wall. There is a liquid level float that is hung from one end of the arm by a flexible chain. A counterweight is mounted on the other end of the arm to pivot it to the position opposite to the one which the weight of the float causes. There is a magnetic switch mounted on the outside of the solid wall, and a magnet on the arm actuates the switch when the float is raised by the level of liquid in the sewer. An alarm circuit may be connected to the switch, as desired.

Abstract: An electro mechanical liquid level sensor is disclosed. The sensor comprises a magnetically operable switch which responds to liquid level in a container to complete a circuit for actuating a warning light or the like. The switch comprises an electrical contact operative in response to a magnetic force which is movable in accordance with liquid level whereby the circuit is completed upon a predetermined change in liquid level. The movable parts of the sensor are self-aligning. The movable contact may be maintained in the circuit closed position independent of liquid level until reset.

Abstract: In a fluid reservoir adapted for mounting on a brake master cylinder, an annular check valve is mounted on the outer periphery of a float and is slidably engaged with the inner wall of the reservoir casing to provide an air-tight seal for brake fluid stored within the casing.

Abstract: An electro-mechanical liquid level sensor is disclosed. The sensor comprises a magnetically operable switch in response to liquid level to complete a circuit for actuating a warning light or the like. The switch comprises a movable electrical contact operative to be moved by magnetic force which is variable in accordance with liquid level whereby the circuit is completed upon a predetermined change in liquid level. The movable parts of the sensor and the structure associated therewith are self-aligning.

Abstract: A liquid reservoir such as that for a brake master cylinder has a float in the liquid, a magnet and a reed switch secured to the float at a fixed spacing so that normally at high liquid level the reed switch is in a given state. When the liquid level falls, the float approaches a body of magnetic material suspended at a desired level in the reservoir or the bottom of the reservoir which comprises magnetic material. When low liquid level is reached, the body of magnetic material alters the flux field from the magnet to either increase or decrease the influence the magnet on the reed switch to cause a change of state of the reed switch thereby indicating low liquid level.

Abstract: The invention contemplates an improved electric switch which changes its state via float response to achievement of a particular liquid level. The construction features mechanical seal and shield structure whereby liquid is kept out of the region of float guidance, with the result that float response is substantially isolated from sloshing action and from liquid contamination.

Abstract: A swimming pool alarm system includes a sensor device mounted at the water line of the pool and carrying a magnetically actuated, normally closed switch and a magnet carried by a float for maintaining the switch closed when the water is at a predetermined level whereby the switch closes if the float moves downwardly away therefrom in response, for example, to lifting of the device out of the pool or from wave motion of the water in the pool.

Abstract: A dual fluid reservoir for a tandem master cylinder includes front and rear fluid chambers communicated to each other and comprises a lateral partition provided within the casing of the reservoir to block free fluid communication between the two chambers after the fluid level within the chambers drops below a lowest level defined by the lateral partition, and an annular partition provided on the lateral partition to form a float chamber therein, the annular partition being higher than the lateral partition in a predetermined length and including a pair of recessed portions corresponding to the lateral partition to permit fluid flow from the two fluid chambers into the float chamber. Thus, a magnetically operable switch device is mounted on the casing between the two chambers to actuate a warning device and a float is disposed within the float chamber for vertical movement and operatively connected to the switch.

Abstract: A vertical float switch, suitable for use as a low water cut-off control or the like, having differential adjustment means is disclosed. The float switch includes a hollow housing forming a float chamber which communicates with a hot water boiler vessel by way of vertically spaced equalizing lines. A non-magnetic sealing tube extends vertically away from the housing and communicates with the float chamber of the housing. A float rod is slidably mounted within the housing by way of a generally cylindrical guiding collar. A float is mounted to the lower end of the rod for translating the rod in accordance with the level of the water within the float chamber. An armature of magnetic material is fixedly mounted to the other end of the rod for translation with the tube in accordance with the level of the water within the boiler. A switch frame is clamped at a predetermined point along the tube, and includes a bracket pivotally mounted thereon for translation toward and away from the tube.

Abstract: A liquid level sensor having a vertical guide tube with one or more magnetically operated switches therein at vertically spaced locations and a free float thereon which rises and falls with the liquid level and as it passes each switch magnetically latches it in one condition until the float returns in the opposite direction and unlatches it. The switches may be normally open, normally closed, or any combination, so that movement of the float past the switches may provide any desired circuit sequence.

Abstract: The position of a control rod located within a nuclear reactor is sensed by a position indicating system utilizing low hysteresis reed switch assemblies. Each reed switch assembly includes a reed switch having an alternating magnetic flux field applied thereto through a coil surrounding the reed switch and energized by an alternating current power source. The amplitude of the alternating magnetic flux field is adjusted to be between a first flux level required to close the reed switch and a second flux level required to open the reed switch. The level of the alternating magnetic flux field is preset to be below the second flux level to maintain the switch in the open position until an external flux field is introduced to raise the total flux level above the first flux level to actuate the reed switch to close. The interaction of the alternating and external flux fields negates the hysteresis band of ordinary reed switches and provides a more sensitive and accurate position indicating circuit.

Abstract: A brake fluid reservoir includes a main body portion having a cap securing a diaphragm between the body and the cap. A sensor is mounted to protrude into the reservoir for indicating a predetermined minimum level of brake fluid in the reservoir. The diaphragm is provided for corresponding movement in response to decreases in the level of brake fluid in the reservoir and also for separating a brake fluid containing portion of the reservoir from an air containing portion. The diaphragm includes an interstice for permitting air in the air containing portion to be drawn into the fluid containing portion under preselected conditions. A protective device surrounds the sensor for maintaining the movement of the diaphragm from interfering engagement with the sensor. The brake fluid reservoir may be used in a vehicle brake system including a master cylinder connected for fluid communication with the reservoir and with the front and rear brakes of the vehicle.

Abstract: A liquid level sensor having a vertical guide tube with one or more magnetically operated switches therein at vertically spaced locations and a free float thereon which rises and falls with the liquid level and as it passes each switch magnetically latches it in one condition until the float returns in the opposite direction and unlatches it. The switches may be normally open, normally closed, or any combination, so that movement of the float past the switches may provide any desired circuit sequence.

Abstract: A fluid level indicator for a reservoir of a brake tandem master cylinder includes a pair of partition walls extending vertically upwardly from the bottom of the reservoir and thereby dividing the reservoir into three chambers. One chamber is in fluid communication with one brake circuit, another chamber is in fluid communication with the other brake circuit, and the third or middle chamber defined between the two partition walls is utilized for sensing and indicating the fluid level of brake oil within the reservoir.