Abstract: A fire alarm is provided with a temperature sensitive element formed of a shape memory alloy, which following cold working, upon heating to a critical temperature, typically for instance about 70.degree. C., returns to the original impressed shape and also retains this shape even after subsequent recooling. Due to the movement of the element there is triggered a self-holding alarm signal, either directly by closing contacts or indirectly. Resetting of the fire alarm can be accomplished by mechanically cold working the element, or by using two-way shape memory alloys through cooling to a lower temperature threshold which can be below room or ambient temperature. A further beneficial construction is realized by combining the arrangement with a different type of fire detection or sensing element, for instance by arranging a shape memory alloy element in a scattered radiation-smoke detector.

Abstract: An electronic controlled microwave oven comprising a temperature measuring probe and capable of performing a temperature operation mode is adapted such that when a temperature operation mode is commanded it is detected whether the temperature measuring probe has been connected and if the temperature measuring probe has not been connected an operator is notified of the fact by means of an alarm. Preferably, such detection of a connection state of the temperature measuring probe is performed after a temperature operation mode key is operated until an operation initiate key is operated. Preferably, the above described alarming is performed using a portion of a digital display.

Abstract: Alarm circuitry in a static structure, e.g., a home, is connectable by plug and socket means to alarm circuitry in an automobile. The alarm circuitry in the automobile includes a relay powered from a source in the structure. Opening of alarm switches in the structure or on the automobile disables the relay to close a switch in the automobile horn circuit causing the horn to sound. The relay cannot be re-energized except by operation of re-set switch means located in the structure.

Abstract: The disclosed temperature monitoring and alarm circuit includes a temperature responsive switch which opens when water temperature exceeds a predetermined point. When the switch opens, a relay is de-energized, thereby activating a latch which activates a visual alarm and closes off a solenoid operated valve on the monitored water source until the over temperature condition is corrected and the circuit is reset.

Abstract: An alarm bell especially adapted to be used in combination with a system which simultaneously detects smoke, fire, current failure, and unauthorized entry into an enclosure. The alarm bell has a housing which suports a bell dome. A mechanical motor is contained within the housing and is connected to actuate a first clapper which strikes the dome and sounds an alarm. A second clapper is actuated by an electric motor and is also placed adjacent to the dome. The first clapper cooperates with an electro-magnet such that the magnetic attraction therebetween prevents movement of the first clapper when the electro-magnet is energized. Accordingly, the electro-magnet can be connected to the same source of current which is used to energize the second clapper so that should the source of current fail, the electromagnet will release the first clapper thereby causing the mechanical motor to sound the alarm.

Abstract: An alarm signal device sounded by a self-contained power source is activated responsive to a variance of temperature within a refrigerator or freezer beyond set limits. A timing circuit in the form of an integrated circuit causes the alarm to sound or flash intermittently for periods of extremely short duration compared to the relatively long periods between warning signals, thus extending the life of the alarm power source.

Abstract: A fire sensing device for actuating associated fire alarm system having a heat receiving plate member of improved heat receiving efficiency for rapidly transmitting any abnormal heat received from environmental atmosphere to a heat-responsive switching means thermally connected to the plate member to actuate the alarm system promptly and reliably is provided. In order to enlarge surface area, the heat receiving plate member has many fins comprising elongated bridging parts defined by adjacent ones of many parallel slits made in the plate member and twisted about elongated axis preferably by an angle of 40.degree. to 60.degree. with respect to the plane of the plate member so as to be raised at both longitudinal edges from the member on its both sides, whereby abnormally heated air passing along a surface or surfaces of the plate member is caused to flow along the fins through or into the slits to rapidly and efficiently transmit its heat to the plate member.