Abstract: A description is given of a sturdy device for establishing and/or monitoring a predetermined filling level in a container, which device exhibits a housing (1), two oscillating rods (3, 4) projecting into the container, a first diaphragm (2) which is fixedly clamped, at its border, into the housing (1), a second diaphragm (6, 6') which is arranged parallel to said first diaphragm in the interior of the housing (1), a piezoelectric element (7, 7') which is arranged on the second diaphragm (6, 6') and is intended for receiving and converting oscillations into an electric output signal and for inducing bending oscillations in the second diaphragm (6, 6'), and in the case of which device the mode of oscillation produced by the piezoelectric element (7, 7') corresponds to the mode of oscillation utilized for inducing oscillation in the oscillating rods (3, 4).

Abstract: An indicating apparatus for indicating a vacuum, particularly for indicating the vacuum on the filtered-air side of an air filter for an internal-combustion engine, including a housing and a piston which is movably disposed in the housing and which separates a vacuum area from an anbient-pressure area. A snap element is provided which is activated by the piston and, at a predetermined vacuum, triggers an electric contact.

Abstract: An apparatus and a method are provided for detecting accumulation of particulates in a fluid stream. A differential pressure switch is incorporated in the apparatus for detecting changes in pressure in the fluid stream passing through a strainer having a filter wherein the particulates accumulate at the filter. A body is insertable into a wall of the strainer wherein the body is in communication with the fluid stream. A pressure responsive device is responsive to changes in pressure in the fluid stream due to accumulation of the particulates. A signal producing device is activated to produce a signal upon detection of a predetermined pressure differential in the fluid.

Abstract: A miniature pneumatic switch apparatus has a diameter of three-eights inches and a height of five sixteenths inches and operates from minimal pressure to 100 psi. A pressure responsive unit includes outer spaced guide walls extending from a pressure movable wall. A switch unit is secured to the guide walls in spaced aligned relation to the movable wall and forms an operating chamber. A spring carrier is mounted within the chamber. The carrier includes a plate having a lateral opening with a beam spring extending therethrough, with the spring ends supported in openings aligned with the plate. An elastic band encircles the support walls and holds the beam spring in place. The opening in the plate facing the switch unit is a flat face, and the opposite face facing the movable wall is curved for line contact with the spring.

Abstract: A miniaturized pneumatic snap action switch includes a glass or metallized ceramic body that has a convoluted metal diaphragm closing the open end with a glass to metal seal. The interior of the switch is provided at a desired pressure by a sealable tubulation port and the switch actuation members include a C-spring and a Belleville spring or washer sealed inside the switch housing. The switchable electrical path is from the metal diaphragm, through the C-spring and Belleville spring, to a centrally arranged conductive termination pin embedded in the closed end of the body. The combination of the C-spring and Belleville spring provide the snap action, and the C-spring has two hemispherical engagement portions that centralize the forces through the center line of the switch. The switch is intended for miniature applications and the switch body is less than 0.75 inches in diameter.

Abstract: A pressure responsive sensor 10 for use with a vehicular air bag inflation system is shown having an electric switch 24 actuatable by a snap acting disc 40 when the gas pressure in the gas storage bottle 48 decreases to a selected low level. The snap acting disc 40 is exposed on one side to the gas mixture P1 in bottle 48 and the opposite side to a reference gas mixture P2 in a reference chamber 34. The gas mixture P2 in the reference chamber is filled to a lower pressure level than hat in the bottle in order to provide switch actuation at the desired level and comprises a mixture of gases to enhance leakage testing and tracking of the pressure vs. temperature characteristic curve of the bottle gas mixture.

Abstract: A pressure responsive sensor 10 for use with a vehicular air bag inflation system is shown having an electric switch 24 actuatable by a snap acting disc 40 when the gas pressure in the gas storage bottle 48 decreases to a selected low level. The snap acting disc 40 is exposed on one side to the gas mixture P1 in bottle 48 and the opposite side to a reference gas mixture P2 in a reference chamber 34. The gas mixture P2 in the reference chamber is filled to a lower pressure level than that in the bottle in order to provide switch actuation at the desired level and comprises a mixture of gases to enhance leakage testing and tracking of the pressure vs. temperature characteristic curve of the bottle gas mixture.

Abstract: Featured for use with a hybrid air bag inflator containing inert stored gas under high pressure is a liquid fueled construction which combines the functions of an initiator, gas generator, and differential low pressure switch into a single device. Instead of being filled with a mixture of combustible gases, the device is filled with a combination of gases and liquids. Alternatively, it makes use of a hybrid squib in conjunction with different combinations of gases and liquids. A pyrotechnic material is used to ignite the mixture regardless of the combination of fuel and oxidant used in the device. A ceramic body is used to house the device. Upon combustion of the mixture, the ceramic body ruptures violently, permitting efficient transfer of the explosive energy to the inert stored gas in the hybrid inflator.

Abstract: A single device acts as a pressure switch, gas generated heater, and an igniter. The device has pyrotechnic material such as a combustible gas in an inner chamber. An outer chamber, that is, a chamber in which the device is positioned, includes a gas that may or may not be combustible. A monitor current flows through a pressure monitor resistor and a bridgewire resistor monitoring continuity. When the pressure in the outer chamber decreases below a threshold value, the pressure monitor resistor breaks continuity and causes a resistance change. If an air bag is to deploy, the bridgewire resistor heats up to a point that the pyrotechnic material in the inner chamber is ignited. The resulting combustion ruptures pressure discs and the outward hot product heats the gas in the outer chamber. The outer chamber ruptures and the heated gas therein flows in the air bag.

Abstract: A refrigerant flow switching device for alternately conveying refrigerant from a high pressure and a low pressure evaporator to a compressor of a refrigeration system, and a refrigerator using such a refrigeration system, includes a refrigerant flow switching valve for alternately conveying refrigerant from the high and low pressure evaporators to the compressor. Said switching valve is controlled by a pressure switch that utilizes the pressure difference between the refrigerant from the high pressure evaporator and that from the low pressure evaporator to cyclically open or close a switch assembly, moving the switch between low and high pressure positions.

Abstract: A pressure sensor that responds to a predetermined rate of change of pressure in the fluid medium comprises a housing that encloses a pressure chamber which has a divider wall that consists of a printed circuit board and a flexible diaphragm which is permeable. The divider wall serves to separate the pressure chamber from the pressure sensitive system in which the sensor is used. The sensor may be used in a pneumatic tire and in such use the flexible diaphragm will be deflected to activate a transmitter when the pressure in the tire changes at a hazardous rate. The sensor will not activate the transmitter when the rate of change of pressure is less than a hazardous rate of change.

Abstract: A hydrostatic pressure sensor, one use for which is to initiate the automatic deployment of emergency marine safety equipment, when a specified depth below the water level is exceeded. The sensor uses a novel method of compensating for ambient air temperature and barometric pressure as a means of reducing the errors in depth sensing caused by changes in the above ambient conditions.

Abstract: A flow switch with a pressure sensing negative rate membrane. The membrane is designed for integral operation with a venturi element and an actuator. The membrane is a snap action device which, when a differential pressure is sensed, deflects from one position to another to operate the actuator.

Abstract: A pressure sensor that responds to a predetermined rate of change of pressure in the fluid medium comprises a housing that encloses a pressure chamber which has a permeable wall and flexible diaphragm that separates the pressure chamber from the pressure sensitive system in which the sensor is used. The sensor may be used in a pneumatic tire and in such use the flexible diaphragm will be deflected to activate a transmitter when the pressure in the tire changes at a hazardous rate. The sensor will not activate the transmitter when the rate of change of pressure is less than a hazardous rate of change.

Abstract: A very low differential pressure switch for detecting pressure differential across two points of a pressurized system. A flexible diaphragm divides two cavities which are exposed to fluid pressures across two points of the pressurized system, and moves a sensor actuating target axially against a compression spring relative to the sensed differential pressures. The switch has a proximity sensor responsive to the axial location of the target to produce an output indicative of a pressure differential condition between the two cavities. The switch has a selected pressure sensitivity and volumetric displacement threshold dependent in part on the cross-sectional area of the flexible diaphragm, size of the compression spring and on the distance between the diaphragm and the proximity sensor.

Abstract: A pressure sensor that responds to a predetermined rate of change of pressure in the fluid medium comprises a housing that encloses a pressure chamber which has a permeable wall and flexible diaphragm that separates the pressure chamber from the pressure sensitive system in which the sensor is used. The sensor diaphragm will be deflected to activate a transmitter when the pressure in the tire changes at a hazardous rate. The sensor will not activate the transmitter when the rate of change of pressure is less than a hazardous rate of change.

Abstract: A control device, switch unit therefor and methods of making the same are provided, the electrical switch unit comprising a switch having a movable actuator, a lever pivotally carried by the switch unit and having one end adapted to be operatively interconnected to a movable part of a control device so as to be pivoted by the movement thereof, the lever being operatively interconnected to the actuator to operate the switch between the different conditions thereof in relation to the pivoted position of the lever, and a pair of mounting plates respectively having holding structure that hold the switch between the plates and respectively having pivot structure that pivotally mount the lever between the plates whereby the plates, the switch and the lever form a self-supporting switch unit.

Abstract: A control device, switch unit therefor and methods of making the same are provided, the electrical switch unit comprising a switch having a movable actuator, a lever pivotally carried by the switch unit and having one end adapted to be operatively interconnected to a movable part of a control device so as to be pivoted by the movement thereof, the lever being operatively interconnected to the actuator to operate the switch between the different conditions thereof in relation to the pivoted position of the lever, and a pair of mounting plates respectively having holding structure that hold the switch between the plates and respectively having pivot structure that pivotally mount the lever between the plates whereby the plates, the switch and the lever form a self-supporting switch unit.

Abstract: The hoppers of several dust precipitators are connected to a common readily accessible monitoring station by discrete conduits each of which has a first open end at a preselected level in the respective hopper, a second open end at the monitoring station and an intermediate portion extending above the corresponding preselected level. Suction which normally prevails in the hoppers tends to maintain closed pivotable flaps for the second open ends of the conduits. If the dust in a hopper accumulates to or rises above the respective preselected level, the corresponding flap is opened by a counterweight and such movement of the flap entails the generation of a signal which is used to evacuate dust from the corresponding hopper and/or to actuate an alarm for the convenience and attention of the persons in charge.

Abstract: An ignition system for projectiles, such as shells, bombs, or rockets is disclosed. The system has a pressure chamber defined by a double-diaphragm switch and a cap of a deformable material. The diaphragm of the double-diaphragm switch, which defines one wall of the pressure chamber, contains one or several perforations, the number and diameter of which depend on the spacing of the diaphragms, the areas thereof and the size of the pressure chamber. The double-diaphragm switch is connected to an electric ignition unit. An electrical circuit is closed only if a projectile housing a percussion fuse and the ignition system impacts on the ground or target after its flight. Any unintended ignition during firing or due to brief impact stress cannot occur.

Abstract: A sealed pressure-responsive switch is manually resettable and trip-free. The switch has a separate snap-acting, bistable, dished metal disc or disc element disposed between a sealed snap-acting pressure-responsive diaphragm and a spring-biased switch arm. The disc moves to an inverted dished configuration with snap action to move the switch arm to a trip position against the arm bias when the diaphragm moves in response to application of a selected fluid pressure. The disc remains in its inverted shape to releasably hold the arm in tripped position until the switch is manually reset even when the diaphragm returns to its original position after removal of the selected fluid pressure from the diaphragm.

Abstract: A method of manufacturing a control device includes interconnecting a switch segment with a terminal and another switch segment and mounting a plurality of electrical circuit elements within a housing with contact sections of the electrical circuit elements being located in different preselected elevations therein, respectively. The terminal is associated with the housing with the another switch segment extending in overlaying spaced apart relation with the contact sections of the electrical circuit elements located in the housing. A method of operating a control device and a control device are also disclosed.

Abstract: An automatic switching system for car cooler is disclosed.In consideration of the fact that the maximum load is imposed on an engine in acceleration period and the vacuum pressure is introduced to a diaphragm room and a diaphragm enforced by a spring member is in response to the vacuum pressure and the switching member is connected perpendicular to the center of the diaphragm is moved to make/break the contact of car cooler.By these provisions, the load on the engine in acceleration can be reduced and fuel consumption can be saved.

Abstract: A miniaturized differential pressure switch comprising a pair of matched square housing sections with a square diaphragm supporting a flat square diaphragm plate which bears against a compression spring that is flexed to open an electrical contact in dependence upon the pressure differential. The compression spring is removably mounted for exchange of springs to vary the range of operation of the switch. The housing section that defines the low pressure chamber provides means for mounting a heat sink that is used for the support of components required for an electronic relay. The switch is suitable for actuation by extreme low pressure, such as 0.01 inch water column.

Abstract: A fluid flow sensing switch device having a housing provided with a fluid flow passage therethrough defined by an inlet and an outlet separated by a valve seat controlled by a movable valve member that is operated by the pressure differential between the inlet and the outlet, the device having an electrical switch construction operatively associated with the valve member and having the switch contacts thereof actuated by the pressure differential. The switch contacts of the switch construction are disposed in the fluid flow passage so as to be exposed to fluid flow therethrough and have a part thereof carried by the valve member.

Abstract: A fluid flow sensing device having a housing provided with a fluid flow passage therethrough defined by an inlet and outlet separated by a valve seat controlled by a movable valve member that is operated by a pressure differential between the inlet and the outlet acting on a flexible diaphragm carried by the housing, the device having an electrical switch construction operatively associated with the valve member and having the switch contacts thereof disposed in the fluid flow passage so as to be exposed to fluid therethrough and being actuated by the pressure differential acting on the flexible diaphragm. The switch contacts comprise a pair of spaced apart contacts carried by the flexible diaphragm and a bridging contact member carried by the valve member and being adapted to make contact with the pair of contacts and thereby bridge the pair of contacts to close the switch construction to operate electronic switching, the electronic switching being disposed inside the housing.

Abstract: A small-sized differential piston unit is disclosed. The piston unit has a cylinder filled with liquid medium and a piston slideably mounted in the cylinder. An operation rod is operatively connected to said piston. An improved sealing member consisting of a membrane is used to completely seal the liquid medium in the cylinder. Control means is provided for imparting fluid resistance caused by the liquid medium to the piston differently between its forward movement and backward movement in the cylinder.

Abstract: A sensor responsive to a differential pressure between a fluid in a reservoir and the surrounding environment for operating a switch to activate and deactivate a pump and maintain the pressure of the fluid in the reservoir within a predetermined range.

Abstract: A fluid flow sensing switch device having a housing provided with a fluid flow passage therethrough defined by an inlet and an outlet disposed in spaced coaxially aligned relation in the housing and separated by a valve seat controlled by a movable valve member that is operated by the pressure differential between the inlet and the outlet, the device having an electrical switch construction operatively associated with the valve member and having the switch contacts thereof actuated by the pressure differential. A pressure regulator is disposed in the housing for regulating the pressure of the fluid that passes from the inlet to the outlet of the housing, the pressure regulator being disposed downstream from the main valve seat so as to act on the fluid after the same passes through the main valve seat from the inlet.

Abstract: A leak detection apparatus (18) is provided in a pressurized assembly (10) to signal a loss of pressure or vacuum downstream from a source of pressure or vacuum. A rod (60,160,260) is carried on a valve (62,162) and a diaphragm (38,138) which seals the source of pressure or vacuum from the system. A loss of pressure or vacuum downstream of the valve (62,162) and diaphragm (38,138) moves the rod (60,160,260) to a signalling position to alert an interested party that the system is lacking pressure or vacuum.

Abstract: A fluid flow sensing device having a housing provided with a fluid flow passage therethrough defined by an inlet and outlet separated by a valve seat controlled by a movable valve member that is operated by a pressure differential between the inlet and the outlet acting on a flexible diaphragm carried by the housing, the device having an electrical switch construction operatively associated with the valve member and having the switch contacts thereof disposed in the fluid flow passage so as to be exposed to fluid therethrough and being actuated by the pressure differential acting on the flexible diaphragm. The switch contacts comprise a pair of spaced apart contacts carried by the flexible diaphragm and a bridging contact member carried by the valve member and being adapted to make contact with the pair of contacts and thereby bridge the pair of contacts to close the switch construction to operate electronic switching, the electronic switching being disposed inside the housing.

Abstract: A fluid flow sensing switch device having a housing provided with a fluid flow passage therethrough defined by an inlet and an outlet separated by a valve seat controlled by a movable valve member that is operated by the pressure differential between the inlet and the outlet, the device having an electrical switch construction operatively associated with the valve member and having the switch contacts thereof actuated by the pressure differential. The switch contacts of the switch construction are disposed in the fluid flow passage so as to be exposed to fluid flow therethrough and have a part thereof carried by the valve member.

Abstract: A pneumatic tire pressure monitor for a tandem set of tires has a housing for being affixed to the outboard tire wheel. The housing includes a first and second chamber communicating with the interior pressure of each pneumatic tire of the tandem set of tires. The housing further includes a third chamber containing hydraulic fluid for maintaining a reference level of pressure. A diaphragm is responsive to pressure differentials between the first and second chambers and the third chamber to activate a latch. The latch releases a visual signal member, which moves from a retracted position within the housing to an extended position in order to signal a drop in pressure in either or both of the tires. In an alternate embodiment, the monitor may be used to monitor the pressure of a single pneumatic tire.

Abstract: A pressure responsive control device including a housing, a control switch unit and switch operating actuator, and a controller unit is disclosed for controlling operation of a refrigeration defrosting device. The actuator includes a bladder formed of thin film material which changes volume when a differential fluid pressure exists across the bladder. The bladder and switch unit are such that bladder volume changes are accompanied by minimal losses thus enabling the controller unit to be enabled in response to extremely slight differential pressures.

Abstract: A device for detecting electrical faults internal of a liquid and gas containing power transformer. Portions of two electrically nonconducting chambers are immersed in, and each chamber has an opening into, said liquid. One of said openings permits the relatively free passage of liquid through same and the other opening contains a liquid-immersed flow-restricting orifice. A sudden change in internal transformer pressure, indicative of an internal transformer fault, creates a pressure differential between chambers because of the liquid-immersed flow-restricting orifice associated with one of said chambers and the viscous properties of said liquid. This internal failure indicating pressure differential is sensed by a suitable differential pressure sensor which, in turn, actuates power transformer fault, indicating means.

Abstract: A liquid flow switch having straight through flow and connections on a common axis. A threaded plug with orifice is interchangable to obtain other rates of specific flow. Flow of fluids through orifice provides a differential pressure to be developed internally of a housing having a pressure responsive diaphragm. The diaphragm supports an actuating element that impinges upon an axially displacable pin extending outwardly of the housing. The pin bears against a flat spring that is flexed to close an electrical contact in dependence upon the specific flow of a liquid.

Abstract: A pressure switch comprising a housing and a movable pressure responsive diaphragm in the housing cooperating therewith to define a sensing chamber. The housing has an inlet passage leading to the sensing chamber and a vent passage leading from the sensing chamber. A check valve allows fluid to flow through the inlet passage into the sensing chamber and prevents flow through the inlet passage in the reverse direction. A pressure relief valve at least partially vents the sensing chamber through the outlet passage in response to the differential pressure across the pressure relief valve reaching about a predetermined magnitude. At least a portion of the diaphragm is movable along a path in response to pressure changes in the sensing chamber and an actuator is carried by the movable portion of the diaphragm. A switch is mounted on the housing in a position to be actuated by the movement of the actuator.

Abstract: A pressure responsive switch for modifying an actuation signal generated through a solenoid valve responding to a sway control signal to limit the operation of a brake applying servomotor and thereby prevent locking of the wheel brakes in a trailer braking system.

Abstract: A pressure switch for use within a pressure chamber containing a gas having a pressure of P.sub.2, said switch including a pressure vessel containing gas having a pressure of P.sub.1, said vessel circumscribed by an end wall at one end thereof, side walls and closed at the second end by a flexible diaphragm, said diaphragm biased in a first position and subjected to P.sub.2 on one surface thereof and to P.sub.1 on the other surface thereof, said diaphragm assuming said first position when P.sub.2 does not exceed P.sub.1 by a predetermined amount and assuming a second position under P.sub.2 when P.sub.2 does exceed P.sub.1 by said amount, and switch means operatively associated with movement of said diaphragm.

Abstract: A control device having an actuator housing and a differential pressure responsive housing secured together so that a certain change in differential pressure in the pressure housing will cause a movable part thereof to move to a new certain position thereof and cause a lever arrangement in the actuator housing to operate an actuator therein. An actuating pin extends between the housings and has opposed ends respectively engaging the movable part of the pressure housing and the lever arrangement of the actuator housing to translate movement therebetween, the ends of the pin not being attached to the movable part and lever arrangement. A tubular bearing means is secured to the pressure housing and telescopically receives the actuating pin therethrough, the tubular bearing member being in fluid communication with the pressure housing so as to provide a fluid bearing for the actuating pin.

Abstract: A hydraulic brake fluid level sensing system having a switch housing above a diaphragm which sealingly encloses a fluid reservoir. A float rod guide extends through the diaphragm and a float rod extends through the rod guide and into the switch housing. A float vertically positions the float rod in accordance with brake fluid level. A switch element is positioned by the float rod to bridge a pair of contacts when the fluid level decreases to a specified level. A slot is provided in the rod guide to provide a vent to the fluid reservoir when the diaphragm is moved down the rod guide by differential pressure thereacross resulting from brake fluid loss.

Abstract: A pressure sensing means having a housing provided with a chamber therein. A double wall fluid operated device is disposed in the chamber of the housing and is carried by the same, the walls of the device defining a chamber therebetween that is interconnected to the exterior of the housing by a passage. A charge of pressure fluid is sealed in the chamber of the housing to initially hold the walls of the device in flat abutting relation in a manner to prevent an adverse permanent set thereof. Subsequently, the chamber of the double wall fluid operated device is interconnected to the pressurized chamber of a container means for a vehicular air bag safety system whereby the pressure sensing means can subsequently detect loss or gain of pressure differential across at least one of the walls of the double wall operated device for detection purposes or the like.This is a continuation of application Ser. No. 321,648, filed Jan. 8, 1973, now abandoned.

Abstract: A casing is disposed in an air pressure chamber of a pneumatic tubeless tire and carries therein a switch cooperating with an alarm to produce an alarm signal upon a fall in the air pressure in the tire below a predetermined value. The switch is controlled by a leaf spring which is deformable by the movements, in one direction, of a flexible diaphragm deformable in response to variations in the air pressure in the tire. The leaf spring is returnable by its resilient force upon the movements, in another direction, of the diaphragm. The casing is fixedly mounted on a wheel rim through a projection extending outwardly of the tire from the casing through the rim.