Abstract: A tire pressure sensor to be fastened to a rim of a vehicle wheel for sensing an inflation pressure of a tire mounted on the rim, the tire pressure sensor comprising a reference pressure chamber having a gas filled reference pressure volume, an electrically conductive diaphragm for sealingly separating the reference pressure chamber at a tire interior, a sensor electric circuit, a contact pin located in the reference pressure chamber and cooperating with the electrically inductive diaphragm for closing the sensor electric circuit when the tire inflation pressure is at a predetermined value, and an additional pressure chamber communicating with the reference pressure chamber and deformable to change the reference pressure volume therein to thereby establish a predetermined reference pressure in the reference pressure chamber.

Abstract: A pressure-biased, temperature sensor means utilizing a cooperating pair of aligned bellows operators in a chamber communicating with a fluid to a reference pressure. One of the bellows is responsive to an elevated temperature of a fluid coolant system and the second bellows, which communicates with the fluid coolant system, is responsive to a decrease in fluid pressure. The aligned bellows cooperate to move a switch actuation means to close a switch thereby completing a signal circuit and energizing a signal means.

Abstract: Extinguisher provided with a temperature compensated pressure controller, comprising a propelling agent and an extinguishing agent under gaseous form, wherein it comprises a sealed chamber filled with a mixture having a thermodynamic characteristic similar to that of the two agents in the extinguisher, a system for measuring the differential pressure exisiting between the inside of the sealed chamber and the chamber per se and a device actuated by the system for measuring the differential pressure and generating an alarm signal when the differential pressure exceeds a threshold value.

Abstract: A pressure-biased, temperature sensor means utilizing a cooperating pair of aligned bellows operators in a chamber communicating with a fluid system. One of the bellows expanding in response to an elevated temperature of said fluid and the second bellows expanding in response to a decrease in fluid pressure. Both of the bellows operate to move a diaphragm operator to close a switch means in a signal circuit thereby completing the circuit and energizing a signal means.

Abstract: A pressure-biased, temperature sensor for monitoring a fluid system for either an over-temperature or under-pressure condition. These conditions are sensed by one of two expandable bellows operators which cooperates with the other bellows operator and a lever and fulcrum arrangement to close a switch, completing a signal circuit and energizing a signal means.

Abstract: A pressure-temperature sensor for monitoring a fluid system for an over-temperature, an under-pressure or an over-pressure condition. The sensor includes a bellows operator enclosed in a fluid-filled housing with a normally-closed, first switch means and a normally-open second switch means. A diaphragm operator and a bellows are responsive to changes in temperature and pressure to, respectively, operate the first and second switches to indicate an over-temperature, an under-pressure or an over-pressure condition.

Abstract: A pressure-biased, temperature sensor for monitoring a fluid system for either an over-temperature or under-pressure condition. The sensor includes a bellows operator immersed in the fluid of a coolant system. The bellows operator expands in response to changes above a predetermined temperature or below a predetermined pressure to complete a signal circuit and energize a signal means.

Abstract: A differential pressure switch with a housing having two faces opposite each other which comprises two approximately coaxial bellows arranged in the housing, so that each bellows has one of its sides securely fastened to a face of the housing, with a dividing sheet arranged between the bellows such that two separated work chambers are formed. Each work chamber is defined by one face of the housing, by a bellows and by the dividing sheet. The dividing sheet has a section projecting sideways through the bellows for switch control.

Abstract: A fluid pressure switch includes a housing with a cylindrical bore, a spring housing bore and a guide bore between the cylindrical bore and the spring housing bore. A shaft member axially disposed in the housing between the bore, has a piston element secured on the end within the cylindrical bore for movement in one direction or another upon a differential between fluid pressure sources as presented to the two opposing surfaces of the piston element. A spring-biasing arrangement is secured to the shaft member on the end within the spring housing bore for opposing movement of the shaft member. The spring-biasing arrangement is adjustable both as to the spring force and as to the spring stop setting. A switch operator member secured to the piston member, spreads contact arms apart upon a predetermined displacement of the piston. The switch operator member has an elliptically-shaped eccentric portion which can be rotated to adjust the point of shaft displacement at which switch operation occurs.

Abstract: A vacuum interrupter comprises an end plate having a central opening through which a movable contact rod extends. A tubular metallic bellows surrounds the contact rod and includes a plurality of annular convolutions at its inner diameter. Guide structure fixed to the end plate lines its central opening and is located outside said convolutions. A sleeve of self-lubricating plastic material surrounds the contact rod and is fixed thereto. This sleeve is disposed within the guide structure and within the tubular bellows and fits closely within said convolutions so that the convolutions are capable of bearing against the sleeve to assist in guiding the rod.

Abstract: A differential temperature control uses a first temperature expansion element for driving a first pivoted lever supporting a selectively operable switch and a second temperature expansion element for driving a second pivoted lever for operating the switch. The position of the switch operating lever with respect to the switch is achieved by either the first or second temperature expansion element which move the first lever and the second lever, respectively, in direct proportion to a change in the corresponding sensed temperatures. In the case of a movement produced by the temperature expansion element controlling the position of the switch, a similar temperature change sensed by the second temperature element would be needed to "chase" the switch to restore a switch actuation relationship to produce a differential temperature control. A selective adjustment of the spacing of the second lever with respect to the switch is used to change the differential temperature that will produce a switch actuation.

Abstract: Pressure drop detectors are provided which are suitable for use in pressurized fluid fire alarm systems. The pressure drop detectors have pressurized fluid circuits provided as channels in the surface of a block of material, including one channel connected to a source of fluid pressure. The channels are associated with valve regions by means of which, with a first diaphragm pressed thereagainst, a required one or more of the channels can be closed off.The pressure drop detectors have a normally pressurized region of the first diaphragm which by means of a first piston normally supports a mechanical linkage of the detector. If the pressure drops however on release of pressure in the circuit connected to the detector, the collapsing of the first diaphragm allows the mechanical linkage to be released thus actuating a fire alarm.

Abstract: A fuel safety switch for the fuel system of a motor is designed to be placed in the fuel delivery system and includes a bellows responsive to the pressure of the fuel within the fuel system for expansion outwardly, coil springs disposed on both sides of the bellows to provide a snap action return of the bellows to a collapsed condition after a reduction in fuel pressure, a first set of contacts activating an over fuel indicator when the bellows is expanded beyond a predetermined limit, and a second set of contacts activating the motor brake retarders, if turned on, when the bellows collapses to the unexpanded state.

Abstract: A vacuum switch incorporating two contact elements arranged in an evacuated housing, the contact elements being in contact with one another in the closed condition of the switch and being separable from one another for cutting-off the current. As to the two contact elements at least one is movable in one direction. At least the movable contact element is secured to a support element which is movably guided in the direction of movement of such contact element and possesses a current terminal separate from the support element.

Abstract: A low voltage cell shorting vacuum switch is biased in the normally open position as well as being protected from the cell corrosive atmosphere by an electrically insulating, resilient elastomeric annular member.

Abstract: A switching device responsive to pressure at one or two inputs with pressure responsive members each of which moves an actuating member in response to pressure variations. First and second electrical switches are positioned to be operated by the respective actuating members and a third switch is mounted for movement with one of the members and actuated by the other member. In one embodiment, a first compression spring acts between a housing and an actuating member which is moved in response to pressure variations. A second spring extends in parallel with the first spring and acts between the housing and a pivotably mounted lever which is lifted by the first actuating member above a desired pressure level.

Abstract: A relay unit associated with a fluid cooled transformer apparatus. The relay utilizes an hydraulic bellows circuit system to sense internal pressure changes developing in a tank member of the transformer apparatus; and it responds to a sudden rise in the pressure to operate an alarm switch. The system includes a group of three bellows, one of which reacts to pressure changes in the tank; and the other two of which respond according to the reaction of the first in controlling operation of the switch. A pivoted bracket and supporting spring arrangement associated with the bellows serves to control operation of the switch and to restrain it from being operated by shocks and the like attendant upon seismic conditions.

Abstract: A guide sleeve for the movable contact rod of a vacuum-type circuit interrupter fits within the usual tubular bellows of the interrupter. The bellows has some of its annular convolutions located axially-inwardly of the axially-inner end of the guide sleeve. A coating of self-lubricating plastic material is provided on the outer peripheral surface of the guide sleeve and on its inner end surface. This coating is sufficiently close to the internal surface of the bellows as to be contacted by said convolutions when the contact rod is axially moved during operation of the interrupter. The lubricating properties of the coating reduce friction between said convolutions and said coated sleeve.

Abstract: A monitor for maintaining an atmosphere of gaseous sulfur hexafluoride supplied to the chamber of an outdoor circuit breaker at a predetermined density, which is to be kept constant, comprising a switch or valve operable to connect the chamber to a source of gaseous sulfur hexafluoride at said density and to disconnect it therefrom and a sensing device comprising a constant volume tube in the chamber filled with gaseous sulfur hexafluoride at the same density as that in the chamber, a compressible bellows in the tube filled with oil, a pair of opposed cascaded bellows supporting an actuator in operable relation to the switch or valve so as to maintain the switch or valve in a neutral position for any change in ambient temperature and wherein a decrease in pressure within the chamber will cause the switch or valve to be operated to supply gas pressure to the chamber.

Abstract: A device for providing a measurement of the value of the ratio of two pressures by sensing the position of a member that is urged in one direction by one pressure and oppositely by the other pressure with the element further having both pressures set against the same movable support of the element. A third pressure of essentially a high vacuum acts on the remainder of the element not acted on by the other pressures and minimizes the effects of temperature while enabling the device to be precise over a wide range of pressures.

Abstract: A condition responsive electrical switch is provided with a housing, and means is movable in the housing between opposite positions for controlling the flow of power through the switch. Means is pivotally movable in the housing for effecting actuation of the controlling means between its opposite positions, and means is operable generally in response to a certain condition for driving the actuation means to pivot it and conjointly move the controlling means toward one of its opposite positions. Means is selectively operable for biasing the actuation means against the driving means to also pivot the actuation means and effect conjoint movement of the controlling means toward the other of its opposite positions.A method of operating a condition responsive electrical switch and a control system are also disclosed.