Abstract: A low-cost, easy to manufacture and maintain pressure responsive switch. The switch includes a pressure responsive diaphragm made from latex rubber that is mounted in a housing base. An annular groove in the housing base communicates with an annular shoulder in a housing cover to compress an O-ring for forming upper and lower chambers, sealing the housing and securing the diaphragm.

Abstract: A switch has a housing defining a closed cavity having opposite, first and second walls. A first control electrode is on the first wall. A first contact electrode is on one of the first and second walls. A diaphragm electrode is across the cavity and spaced from the first contact electrode, the diaphragm electrode being responsive to electric potential relative to the first control electrode for flexing across the space and into contact with the first contact electrode, whereby to close the switch.

Abstract: A switch detects a vacuum that is created by suctioning air through a port hole in a media support surface. The switch includes a first layer having (i) a first hole therein which is at least partially aligned with the port hole in the media support surface and (ii) a conductive region, and a second layer, which is disposed above the first layer relative to the media support surface and which is substantially non-conductive. The second layer has a second hole therein which aligns, at least in part, to the first hole in the first layer and to the port hole in the media support surface so as to allow air to flow through the port hole, the first hole, and the second hole. A third layer, which is disposed above the second layer relative to the media support surface, comprises a printed circuit pattern that aligns, at least in part, to the second hole. The printed circuit pattern on the third layer comprises an open circuit.

Abstract: A pressure switch is illustrated that includes only three piece parts--two dimpled covers and a spacer. By selecting both the type and thickness of cover materials, switching pressure ranges can be selected to accommodate a very wide range of operating pressures. Fine adjustment of the switching pressure may be made by modifying the cover dimples. Reliability and a hermetic seal is attained through the use of appropriate materials for the covers and spacer, together with active metal braze seals which provide high temperature, moisture and chemical resistance. A vacuum port is added for providing the ability to modify the air pressure within the pressure switch.

Abstract: A diaphragm switch includes a housing having an interior space and a substrate in the housing supporting an electrical contact. A flexible membrane has opposite first and second surfaces, the first surface being electrically conductive. The membrane is mounted in the housing proximate the substrate with the first surface minutely spaced apart from the electrical contact. An activation pressure in the housing is communicated to the second surface of the membrane whereby deformation of the flexible membrane caused by the activation pressure closes the minute spacing between the electrically conductive first surface and the electrical contact, thereby completing an electrical circuit. A leakage path is operatively associated with the membrane between the first and second surfaces to equalize static pressure on both surfaces, whereby the flexible membrane is not deformed and the circuit is not complete in the absence of the activation pressure.

Abstract: A volumetric pump for administering intravenous fluids to a patient comprises a housing having an elongate cavity therein with an open and a closed end. A resilient sheet of material having a centrally-located aperture covers the open end, and a pump shaft is slidably disposed through the aperture to form a sphincter seal therebetween. An inlet conduit leading from a fluid source (an IV bag) passes through the housing into the cavity near the open end thereof, and an outlet conduit leading to a fluid sink (the patient) passes through the housing from the cavity near the closed end thereof. The shaft is driven back and forth in reciprocating motion inwardly and outwardly of the cavity to produce, respectively, a positive pressure forcing fluid out of the outlet conduit to the fluid sink, and a negative pressure forcing fluid from the fluid source through the inlet conduit.

Abstract: A bridging member extending across a cavity in a semiconductor substrate (e.g. signal crystal silicon) has successive layers--a masking layer, an electrically conductive layer (e.g. polysilicon) and an insulating layer (e.g. SiO.sub.2). A first electrical contact (e.g. gold coated with ruthenium) extends on the insulating layer in a direction perpendicular to the extension of the bridging member across the cavity. A pair of bumps (e.g. gold) are on the insulating layer each between the contact and one of the cavity ends. Initially the bridging member and then the contact and the bumps are formed on the substrate and then the cavity is etched in the substrate through holes in the bridging member. A pair of second electrical contacts (e.g. gold coated with ruthenium) are on the surface of an insulating substrate (e.g. pyrex glass) adjacent the semiconductor substrate. The two substrates are bonded after the contacts are cleaned.

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 temperature compensating low pressure sensor for verifying loss of gas from an inflator of a vehicle restraint safety system. The sensor includes a housing and a pressure diaphragm in communication with the fluid in the inflator. A temperature sensitive bimetallic thermostat is disposed within the housing. The thermostat expands with relation to a change in temperature of the fluid at the same rate as the pressure diaphragm. A retainer in communication with the pressure diaphragm is movably disposed in the housing. A stack of spring washers is disposed between the retainer and the thermostat for counteracting the pressure of the fluid acting upon the diaphragm. A contact arm in contact with the thermostat moves with the retainer.

Abstract: This invention provides a pressure switch and a method of manufacture thereof, which allow the air vent hole to be formed very small in diameter so that the engine oil can be reliably prevented from flowing out through this air vent hole.The reduced diameter portion of the air vent hole 13 is formed in the following steps during the process of resin-molding the insulating cap 3 of the pressure switch 1. After the air vent hole 13 having the outwardly projecting portion 14 is formed, the recessed portion 16 of the jig 17 is placed in contact with the circumferential surface of the projecting portion 14 of the air vent hole 13. The jig 17 is pressed against the projecting portion 14 of the air vent hole 13 with a specified pressure to deform the projecting portion 14 and thereby reduce the inner diameter of the air vent hole 13 at the end.

Abstract: A bridging member extending across a cavity in a semiconductor substrate (e.g. single crystal silicon) has successive layers--a masking layer, an electrically conductive layer (e.g. polysilicon) and an insulating layer (e.g. SiO.sub.2). A first electrical contact (e.g. gold coated with ruthenium) extends on the insulating layer in a direction perpendicular to the extension of the bridging member across the cavity. A pair of bumps (e.g. gold) are on the insulating layer each between the contact and one of the cavity ends. Initially the bridging member and then the contact and the bumps are formed on the substrate and then the cavity is etched in the substrate through holes in the bridging member. A pair of second electrical contacts (e.g. gold coated with ruthenium) are on the surface of an insulating substrate (e.g. pyrex glass) adjacent the semiconductor substrate. The two substrates are bonded after the contacts are cleaned.

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: In the case of a switching element, a pressure-compensation element (20) is inserted in the base body (10) of the terminal strip (11) in a recess so that a pressure compensation is possible between the interior of the housing (17) and the outer atmosphere. By means of this special arrangement of the pressure-compensation element (20) in the terminal strip (11) it is possible to test the functional capability of the pressure-compensation elements in the installed state in a simple way without additional testing processes.

Abstract: A microdevice in the form of an electrical switch. A microdevice for providing switching at a high repetition rate, including a cell divided into two chambers by a bistable movable membrane. A charge of gas in the cell and a source for directly heating the gas to increase the gas pressure and move the membrane, the source for heating including a pulsed source for generating transient gas pressure increases, with the cell including an arrangement for cooling the gas for reducing the gas pressure after an increase.

Abstract: The steam generator according to the invention consists of a main vessel 1 equipped with heating devices 12 controlled by control devices 13. The water level in the steam generator is kept at an average level 5 by control devices 13 which control a water inlet solenoid valve 10. Measurement of the average water level 5 is achieved by a pressure switch 20 that is exposed to the pressure inside a measuring vessel 18 that communicates with the main vessel 1 via a lower measuring opening 22. Balancing pipework 34 links the pressure switch 20 to the pressure of the steam produced in the steam generator. Pressure switch 20 generates measuring signals that are sent via conductors 17 to control devices 13 in order to actuate solenoid valve 10.

Abstract: A pressure-measuring head for measuring the pressure of a fluid consists of a membrane-like diaphragm (6), which separates a pressure chamber (4) from a reference chamber (7), to which the pressure-sensitive elements, e.g., thick-film resistors or strain gauges, are applied. Under the effect of the pressure in the pressure chamber, these pressure-sensitive elements perform a deflection which is proportional to the pressure occurring in the pressure chamber. An electric contact is switched during simultaneous displacement of the membrane (6) arranged in a sensor housing by a predeterminable distance (19) after a defined pressure value has been reached in the pressure chamber. A measuring head of such a design is also able to assume a swithing function without additional auxiliary energy, besides sending an electrically processable pressure signal.

Abstract: A reversing switch and more particularly a diaphragm operated electrical polarity reversing switch which has general utility but in the application the reversing switch is disclosed for use in combination with a vehicle mounted spray device including a discharge nozzle which may be used for applying chemicals, liquid fertilizers and other liquids such as when applying such materials alongside of roadways to effectively apply liquid throughout the width of the road right-of-way in which spray nozzles are mounted adjustably on a pivotal arm-type support assembly at the right front of a vehicle and a control arrangement is oriented in the cab of the vehicle to enable the vehicle operator to control the spray apparatus.

Abstract: A micromachined pressure switch and method of fabrication from silicon wafers using aligned fusion bonding. Pattern etched thermally grown silicon dioxide insulating pads are used to determine the size of silicon pressure membranes on an upper silicon wafer, with the desired switch gap set by the oxide thickness. The silicon membranes are formed by controlled thinning the upper silicon wafers. V-shaped vent grooves are pattern etched into a bottom silicon wafer to form electrodes to which the insulating pads are fusion bonded. The area between the electrodes and the membrane forms wells of specified sizes into which the membranes deflect upon application of pressure. The pressure switch operates when the membrane is deflected to contact the electrodes in the bottom wafer, and closes at the desired pressure threshold for both directions of pressure change with negligible hysteresis. The method of fabrication applies to a single element pressure switch as well as to an array of pressure switches.

Abstract: An electrical switch with pyrotechnic control includes a housing containing a pyrotechnic composition and at least two contacts applicable, for example, to fire an explosive charge in a military application such as a warhead. The switch includes a thin foil having at least one conductive part spaced in the vicinity of the pyrotechnic composition by a spacing washer directly opposite the contacts. Triggering of the composition throws the thin foil in contact with the contacts to complete an electrical connection. The switch is operable with a small amount of the pyrotechnic composition and has a reduced controllable response time.

Abstract: Two electrically conductive diaphragms which are disposed in generally parallel relation and are symmetrical mirror images of each other are joined to a non-conductive ring. The diaphragms are joined in a pressurized atmosphere of argon at, for example, 3000 psi. When so pressurized internally and with lower external pressure, the diaphragms do not contact each other. When pressurized externally to a pressure to a predetermined level higher than the internal pressure, the diaphragms make contact with each other to close an electric circuit. If pressure leaks into the switch or the external pressure drops, the diaphragms separate and break contact with each other.

Abstract: A semiconductor transducer or actuator is disclosed. The transducer and actuator each include a deflecting member with corrugations producing increased vertical travel which is a linear function of applied force. An accurate and easily controlled method that is insensitive to front-to-back alignment is also disclosed for forming uniform corrugations of precise thickness; independent of the thickness of the deflecting member. The cross-sectional shape of the corrugations is not limited by the etching technique, so that any configuration thereof is enabled.

Abstract: A pneumatic pressure detector for use in an overheat or fire alarm system utilizes a known capillary type sensor tube which has absorbed in it a gas. Overheat or fire condition causes the gas to expand which then actuates an associated deformable diaphragm to close an electrical switch. To insure that the system pressure is maintained and no fault condition exists, the compact detector also uses a deformable diaphragm associated with an integrity switch which opens if the pressure falls below normal. Both of these diaphragms are juxtaposed to form the plenum to which the sensor tube is attached thereby saving weight and space.

Abstract: An improved pressure switch of the pulse or pressure wave sensitive type includes a switch housing with an internal diaphragm chamber. A relief vent with a fixed orifice disk is provided in the diaphragm chamber. A diaphragm is mounted in the diaphragm chamber which includes an electrical contact mounted on and movable with the diaphragm. An adjustable contact is threaded through a tapped terminal link in the switch housing to position a contact surface on the adjustable contact adjacent to the electrical contact mounted on the diaphragm. The adjustable contact includes a slotted end. A slotted, round lock nut is threaded on the adjustable contact. To provide an electrically reliable contact, a biasing member is positioned between the round lock nut and the tapped terminal link providing a positive thread bias on the contacting threads of the adjustable contact and the terminal link.

Abstract: A pressure responsive switch having upper and lower contact assemblies with a snap acting member and an electrically conductive member sandwiched therebetween. The assemblies each include an insulating body with a hollow center and an electrically conductive member having a contact in the center portion and extending externally of the body. The snap acting member is in constant engagement with the sandwiched conductive member and normally in engagement with the electrically conductive member of the upper assembly. When a pressure is applied which is sufficient to cause the snap acting member to snap into its second stable state, the connection thereof with the electrically conductive member in the upper contact assembly is broken and connection is made with the electrically conductive member in the lower assembly. The switch is normally closed by removing the portion of the electrically conductive member in the lower assembly which extends externally thereof.

Abstract: Conductive pads are disposed in a housing which consists of a degassed, non-compressible, electrically insulating fluid. One of the pads is mounted on the underside of a push-button, and the push-button is surrounded by a flexible membrane which closes one end of the housing. When the push-button is pressed, the fluid between the conductive pads is displaced, and the membrane stretches sufficiently to accommodate the displaced fluid.

Abstract: The invention concerns an on-off switch (1) for high-frequency currents. This switch (1) comprises a housing (2) made of an electrically non-conducting plastic and sealed at both its upper and its lower sides by electrically conducting contact parts (3,4). A metal bellows (14) is present in the housing (2) and is connected at one end to one of the contact parts, (4) and at its other end to a contact head (25). Using compressed air, the contact head (25) can be moved to make contact with the other contact part (3) or be removed away from it.

Abstract: An electrical interconnection is provided between a tubular element (10) formed of a thin walled plastic material made conductive (16) and a further contact (18,56) by fluid pressure driving the material to engage the further contact. Positive and negative pressures are contemplated and assemblies (110) of contacts (90) are arranged to become commonly activated to interconnect arrays of contacts between electronic packages.

Abstract: A normally closed pressure responsive switch has upper and lower housings attached to one another with an electrically conductive snap acting disc placed therebetween. The lower housing includes a base having a recessed area in which a stationary electrical contact is mounted. The snap acting disc is placed on top of the base with a side having a convex configuration facing the stationary contact. An electrically conductive member is placed over the disc with a plurality of contact tabs engageable with the outer peripheral portion of the disc. The upper housing includes a retainer having a bore in which a pressure converter slides. Ribs formed on the bottom of the pressure converter are adapted to engage the outer peripheral portions of the disc between the contact tabs and are captured in grooves of the retainer to restrict angular movement of the pressure converter.

Abstract: A pressure switch for use in a device for alarming the reduction of pneumatic pressure of vehicle tire is disclosed. The switch comprises a base board, a bellofram secured to the base board and having conductive coating of one electric contact applied to the inner surface and the outer surface thereof and having both bellows and diaphragm characteristic, a housing provided to enclose the bellofram and for defining a hermetic chamber, and a conductor provided at inner portion and outer portion of the bellofram near the center of the diaphragm portion thereof and for forming another electric contact. A back pressure is applied to the inner portion or outer portion of the bellofram against the pneumatic pressure of a vehicle tire.

Abstract: A pressure responsive switch having upper and lower contact assemblies with a snap acting member and an electrically conductive member sandwiched therebetween. The assemblies each include an insulating body with a hollow center and an electrically conductive member having a contact in the center portion and extending externally of the body. The snap acting member is in constant engagement with the sandwiched conductive member and normally in engagement with the electrically conductive member of the upper assembly. When a pressure is applied which is sufficient to cause the snap acting member to snap into its second stable state, the connection thereof with the electrically conductive member in the upper contact assembly is broken and connection is made with the electrically conductive member in the lower assembly. The switch is normally closed by removing the portion of the electrically conductive member in the lower assembly which extends externally thereof.

Abstract: A reverse flow prevention device for combustion apparatuses control operated by electrical power, and which is provided with a combustion gas discharge tube for discharging the combustion process by-product. The reverse flow device comprising a reverse flow gas collecting tube installed within the combustion gas discharge tube for collecting reverse flow gas. The reverse flow device also comprises a detection means, with a function of detecting a reverse flow gas and turning OFF the combustion apparatus when the pressure of the reverse flow gas acting on the detection means is above a certain level.

Abstract: A liquid injection recording apparatus having a recording head for injecting ink toward a recording medium to thereby effect recording, an ink tank storing therein ink to be supplied to the recording head, and an ink remain detector provided within a supply path communicating the recording head with the ink tank are presented. The ink remain detector has an ink chamber having at least one wall surface thereof formed of a flexible film member, and at least two detector means responsive to the displacement of the film member.

Abstract: A diaphragm-type inertia switch for sensing deceleration places the inertial mass in the chamber that contains the contacts. The other chamber has a thin concave-convex shape that gives the switch a low profile. The switch has a molded plastic base containing a test coil for attracting the inertial mass to test the switch. A mechanism for calibrating the switch is also included.

Abstract: A microengineered pressure actuated switch includes a domed diaphragm having a snap-action response between defined states (d.sub.1, d.sub.5) of the diaphragm. This response is to an applied pressure differential across the diaphragm. The diaphragm is supported on a substrate of semiconductor material. In a method of making such a switch, a layer of inorganic material is provided on one side of a substrate of semiconductor material. Semiconductor material is removed from the substrate such that a defined region of the layer is not in contact with the semiconductor material, this defined region forming the diaphragm. The layer of inorganic material is so stressed that after semiconductor material is removed, the layer assumes a domed configuration and incorporates a pre-bias in the direction of doming.

Abstract: Layers of a thin, electrically insulating material are bonded together to form a switch. The bottom layer of the switch has electrically conductive areas aligned with openings through a second layer. A third layer has a pattern of spaced lines of an electrical conductor positioned over the openings in the second layer. Fluid pressure applied to the bottom layer causes flexing of the bottom layer toward the third layer to bring the electrically conductive areas into contact with the pattern of conductive lines on the third layer, thereby closing the switch. A vent chamber in the second layer is pneumatically coupled to the openings in the second layer so that when the switch is closed air in the openings in the second layer can be vented to the vent chamber. The switch can be used to sense changes in fluid pressure in a water system, for example.

Abstract: An inertia switch for a supplemental inflatable restraint system. The switch comprises a casing that is divided into two chambers by an axially movable diaphragm. The diaphragm carries an electrical contact on one face and an inertial mass on the other. A pair of terminals are disposed in the path of travel of the electrical contact so that when the switch is subjected to axial deceleration force the contact is urged toward the terminals. Actual contact is made when the deceleration force equals or exceeds a predetermined deceleration characteristic. The deceleration characteristic is a function not only of the diaphragm, the electrical contact, and the mass, but also of a control orifice located in an orifice that communicates the two chambers with each other. The chambers are constructed such that air is forced from one chamber into another through the control orifice when deceleration occurs and this imparts a dampening to the motion of the diaphragm.

Abstract: A pressure switch for monitoring a tire pressure of a motor vehicle tire is fastened to a wheel rim and is actuated by the inflating pressure in the tire. The pressure switch comprises a reference pressure chamber which is sealed off by an electrically conductive switching diaphragm in the direction of the tire, and carries a contact pin interacting with this diaphragm. The switching diaphragm has a mass which is controlled as a function of centrifugal force in response to tire rotation such that the switching point of the pressure switch can be changed automatically as a function of vehicle speed.

Abstract: A multicontact vacuum responsive switch includes a housing divided into first and second chambers by a diaphragm. The first chamber is connected to a vacuum source while the second chamber communicates with atmospheric pressure, so that the diaphragm is movable within the housing in response to a pressure differential between the first and second chambers. A plate is connected to the diaphragm for movement therewith, and has an electrically conductive portion of a predetermined pattern. A plurality of electrical contacts are mounted in the housing and slidably contact the plate such that the contacts may selectively contact the electrically conductive portion of the plate in response to movement of the diaphragm means, which also cause movement of the plate. One of the contacts always contacts the conductive portion, and so is a reference contact.

Abstract: A pressure sensitive electrical switch consists of a housing in which two pressure chambers are formed. The pressure chambers are separated by a flexible diaphragm. The flexible diaphragm is made from electrical conductive material. Conductors extend into the housing to provide terminals which are spaced from the diaphragm when the pressure in the two chambers is substantially equal. When a pressure differential is established between the two chambers, the diaphragm may be deflected into contact with one or other of the terminals of the conductors. In use, the diaphgram is connected in an electrical circuit and each of the conductors is connected in an electrical circuit such that when contact is made between the diaphragm and one of the conductors, the electrical circuit will be complete. Because the diaphragm is at least partially permeable, this switch is intended to be used to monitor changes in pressure which occur between the two chambers over a relatively short period of time.

Abstract: A fluid-actuated pressure switch for a four-speed automatic transmission system having a diaphragm to prevent fluid contamination of the electrical switch contacts and features a leakage path which eliminates air trapped within the fluid.

Abstract: An automotive transmission control is shown having pressure switches to sense the state of actuation of solenoid valves to provide logic signals to a microprocessor type of transmission control. The pressure switches, which sense the pressure of hydraulic fluid controlled by the solenoid valves, use a dished shaped metallic diaphragm characterized in that the pressure-deflection curve of the center of the diaphragm has minimal hysteresis and reflects that the diaphragm is relatively stiff having a positive coefficient of pressure with increasing deflection up to and above a selected pressure level at which level the center accelerates between d.sub.1 and d.sub.2. The diaphragm is loosely held on a conductor at 0 psig with the fluid pressure when it increases forcing the diaphragm into sealing and electrical engagement with the conductor.

Abstract: An acceleration sensor for an automotive inflatable occupant restraint system employs a rolling diaphragm to divide a housing into two chambers in fluid communication through orifices across the diaphragm. The orifices damp the motion of an acceleration sensing mass with respect to the diaphragm.

Abstract: A tire pressure sensor for motor vehicles comprises a pressure switch which is actuated by the tire pressure for monitoring the tire pressure. The pressure switch has a reference pressure chamber which is closed in the direction of the tire by means of an electrically conducting diaphragm and carries a contact pin which is contacted by the middle area of the diaphragm in order to close an electric circuit when there is sufficient air pressure in the tire. In order to trigger an alarm signal during a leak in the reference pressure chamber a leakage check of the reference pressure chamber is realized in that an air gap is located between the contact pin and the middle area of the diaphragm when there is equal pressure on both sides of the diaphragm.

Abstract: The invention relates to a pressure switch comprising an insulating housing fitted with contact tabs and receiving moving contact members, a conductive washer, and a membrane subjected to pressure. The pressure switch includes two moving insulating members (15, 19), two contact members (16, 20), two associated springs (17, 21), and a pusher (14) which is conductive and in contact with the membrane. The fixed conductive washer (11) has a central hole through which a cylindrical projection provided on one of the insulating moving members (15) passes, with a rod on the pusher (14) sliding inside said cylindrical projection so that the insulating moving members (15, 19), the contact members (16, 20), and the associated springs (17, 21) are all disposed on the same side of the fixed conductive washer which therefore constitutes one end of the cavity (9) in the insulating housing.

Abstract: A pressure switch comprising a housing, a diaphragm that divides the inside of the housing into a pressure chamber and an atmospheric chamber, a switch portion mounted in the atmospheric chamber, and a resilient cap fitted over the housing. A porous filter is held between the housing and the cap. The diaphragm is actuated according to the difference between the pressures inside the chambers. The switch portion consists of a movable contact and a fixed contact, and is connected to terminals.

Abstract: An automotive transmission control is shown having pressure switches to sense the state of actuation of solenoid valves to provide logic signals to a microprocessor type of transmission control. The pressure switches, which sense the pressure of hydraulic fluid used to actuate the solenoid valves, use a dished shaped metallic diaphragm characterized in that the pressure-deflection curve of the center of the diaphragm has minimal hysteresis and reflects that the diaphragm is relatively stiff having a positive coefficient of pressure with increasing deflection up to and above a range of set point pressures within which the effective spring rate of the diaphragm changes with the diaphragm being relatively supple but having little or no negative coefficient of pressure.In a first embodiment a housing is shown in which a conductive lead pattern is molded in the housing with a plurality of switching stations.

Abstract: A window security device which operates on differential gas pressure theory to trigger an alarm upon pressure equalization. A plug which completes the electric activator circuit includes biasing springs or similar devices to urge the plug out of contact with the activator circuit to trigger the alarm upon disturbance or breakage of one of the window glazing panels.

Abstract: A trimmable microminiature force-sensitive switching device for detecting the state of external conditions, such as pressure, acceleration and temperature, is disclosed. The device includes a silicon substrate having a reduced-thickness, deflectable member adapted to change its deflection in response to changes in the external condition to be detected. Increasing deflection of the member establishes electrical contact between a common contact and first one, then progressively more, spaced electrical contacts of a plurality of switches. Each of the spaced electrical contacts is connected to a common terminal. Trimming of the switching device is accomplished by application of a preselected external force, such as pressure, that causes the deflection of the deflectable member and the closing of one or more of the switches.

Abstract: A device primarily for attachment to the spout of a teakettle for generating a musical signal in response to the vapor pressure of boiling water. A diaphragm distorts in response to the pressure and closes an electrical switch which applies battery voltage to a circuit in which a representation of a pre-selected tune is stored. The tune is applied to a piezoelectric speaker within a resonating housing to audibly signal the user that the water in the teakettle is boiling.

Abstract: A fuel delivery system which includes a fuel pump and a dc motor, which are preferably contained within a unitary housing. A pressure-sensitive switch, which is either contained within the unitary pump/motor housing or as a separate structure, includes a movable contact positioned within a housing so as to form a first chamber for receiving fuel under pressure and a second chamber for venting to atmosphere. A spring urges the movable contact against a second contact for applying electrical power to the pump motor. When the pump output pressure exceeds the force exerted on the movable contact by the spring, electrical conduction between the switch contacts is broken and motor power is interrupted. Current to the pump motor is thus pulse-width modulated as a function of pump output pressure, fuel demand, and the adjustable force exerted by the pressure switch spring.