Heating Circuit Patents (Class 340/655)
  • Patent number: 8947248
    Abstract: Damaging a touch sensor is prevented by an input apparatus including a pressing load detection unit 102 for detecting a pressing load applied by a pressing object pressing a touch sensor, a contact area detection unit 103 for detecting a contact area of the object on the sensor, a memory unit 105 for storing a pressing load threshold for receiving an input and a damage threshold higher than the pressing load threshold and varies according to the contact area, a control unit 104 for obtaining the pressing load threshold and the damage threshold corresponding to the contact area from the memory unit, and receiving the input when the pressing load reaches the pressing load threshold, or generating a warning signal when the pressing load reaches the damage threshold, and a notification unit 106 for receiving the warning signal from the control unit and outputting a warning.
    Type: Grant
    Filed: August 11, 2011
    Date of Patent: February 3, 2015
    Assignee: KYOCERA Corporation
    Inventor: Makoto Chishima
  • Patent number: 8704630
    Abstract: In one or more embodiments, an intelligent communications device is disclosed. In one embodiment, an apparatus is disclosed for controlling the operations of temperature-sensitive electronic devices in an enclosure, based on a requisite temperature range. The apparatus includes a main circuit board with a plurality of secondary circuit board connectors that are operative to connect secondary circuit boards to the main circuit board. The apparatus also includes one or more temperature sensors that are operative to sense temperature within the enclosure, and one or more selectively actuatable heating elements that are mounted to the main circuit board in proximity to the plurality of secondary circuit board connectors. Each heating element is operative to emit heat when actuated.
    Type: Grant
    Filed: October 6, 2010
    Date of Patent: April 22, 2014
    Assignee: Itron, Inc.
    Inventors: Charles W. Melvin, Jr., Robert Bryan Seal, Michael Dempsey, Tyler Charles Poschel, Jacob Ryan Magee
  • Publication number: 20130265168
    Abstract: An electric current flow indicator senses electrical current flowing through an electrical device and produces a visible feedback to indicate proper operation. The current flow indicator has a voltage and current regulation circuit having first and second inputs connected to first and second conductors, respectively. The circuit converts an AC line voltage carried by an electrical supply cord into a limited low voltage DC current. A toroidal core inductor coil and at least one current indicating LED are connected to the circuit. The first conductor passes through a center of the inductor coil. A transistor amplifier is connected to an output of the inductor coil for energizing the current indicating LED when an electrical current conducts through the first conductor. The flow indicator can be integrated into an electrical supply cord, a male or female electrical cord end, a single or duplex electrical outlet, or a universal plugin adapter.
    Type: Application
    Filed: April 8, 2013
    Publication date: October 10, 2013
    Applicant: Osborne Industries Inc.
    Inventor: Richard Burton Murphy
  • Patent number: 8395489
    Abstract: A vehicle burglar alarm circuit includes a transformer including an input unit having taps and a center tap, and an output unit magnetically coupled to the input unit; a first and a second power source each having one electrode connected to the center tap to respectively output a higher voltage and a lower voltage; a driving unit including switching elements respectively having one ends connected to the taps and another ends respectively connected to the other electrodes of the power sources; a PWM controller outputting signals by which the switching elements are alternately turned on and off; and a power selecting unit for selecting one of the power sources. The PWM controller generates a first on-duty ratio when the first power source is selected and a second on-duty ratio when the second power source is selected such that the first on-duty ratio is smaller than the second on-duty ratio.
    Type: Grant
    Filed: April 27, 2011
    Date of Patent: March 12, 2013
    Assignee: Panasonic Corporation
    Inventor: Yutaka Abe
  • Patent number: 7999689
    Abstract: Device operation sensing and control apparatus for use in combination with a wireless security panel which communicates with a remote operations center, to facilitate independent at-home living of, for example, semi-autonomous elderly persons. One apparatus embodiment includes a remotely controlled AC power receptacle module controllable by signals from the wireless security panel and into which a device such as a microwave oven is plugged. An AC current sensor is connected to an alarm system transmitter for transmitting a signal when the device is in use. Another apparatus embodiment senses operation of and allows remote control of power to an electric range. First and second timers and associated alarm system transmitters transmit a “RANGE ON” signal to the wireless security panel when the electric range is in use, and a “RANGE ON FOR X TIME” signal when the electric range has been use for a predetermined length of time.
    Type: Grant
    Filed: October 30, 2008
    Date of Patent: August 16, 2011
    Assignee: SimplyHome, LLC
    Inventors: D. Allen Ray, Richard W. Bahr, Scott C. Jaeger, Jonathan M. Rohr
  • Patent number: 7796028
    Abstract: Circuitry for detecting magnetic fields includes a first magnetoresistive sensor and a second magnetoresistive sensor configured to form a gradiometer. The circuitry includes a digital signal processor and a first feedback loop coupled between the first magnetoresistive sensor and the digital signal processor. A second feedback loop which is discrete from the first feedback loop is coupled between the second magnetoresistive sensor and the digital signal processor.
    Type: Grant
    Filed: August 1, 2006
    Date of Patent: September 14, 2010
    Assignee: Battelle Energy Alliance, LLC
    Inventors: Dale K. Kotter, David F. Spencer, Lyle G. Roybal, David T. Rohrbaugh
  • Patent number: 7576304
    Abstract: A device for monitoring the voltage or current applied to sensitive components on a circuit board by an assembly tool protects the sensitive components from damage caused by the voltage or current applied to the circuit board.
    Type: Grant
    Filed: November 2, 2005
    Date of Patent: August 18, 2009
    Assignee: 3M Innovative Properties Company
    Inventor: Vladimir Kraz
  • Patent number: 7425896
    Abstract: A tag testing device uses an infrared camera to take an image of a plurality of radio frequency identification tags, compares the image with a stored standard tag pattern image storage, and detects defective tags based on the comparison. A radio wave transceiver bulk reads the tags using anti-collision, a tag response counter counts a number of tag responses, and a defective tag detector compares a number of heat emitting tags based upon the image processing with a number of tag responses counted by the tag response counter. If the number of heat emitting tags does not match a number of responsive tags, a number of the tags tested are changed by partially shielding the tags and the radio wave transceiver repeatedly bulk reads the tags using the anti-collision function while a shielding range is gradually changed, thereby narrowing down other possible defective but heat emitting tags.
    Type: Grant
    Filed: November 22, 2005
    Date of Patent: September 16, 2008
    Assignees: Fujitsu Limited, Fujitsu Frontech Limited
    Inventor: Hiroshi Kawamata
  • Publication number: 20070290872
    Abstract: A relay apparatus for relaying communication between a water heater main body and a radio remote control unit, comprising: a switch section for setting an address of the radio remote control unit; a control section for establishing communication with the water heater main body and commanding and controlling to read out maintenance information stored in the water heater main body assuming that input information at the switch section is a request from the radio remote control unit having an address which was set by operation of the switch section; and a display section for displaying the maintenance information received from the water heater main body.
    Type: Application
    Filed: May 29, 2007
    Publication date: December 20, 2007
    Applicant: RINNAI CORPORATION
    Inventors: Tomomi Yamada, Keiji Kato
  • Patent number: 7301468
    Abstract: Heating coils used in an electric furnace used to process semiconductor wafers are monitored on a real time basis by sensing the AC current in a power line delivering electrical power to the furnace. The AC current is sensed by a coil positioned around and magnetically coupled with the power line. The sensed AC current induces an AC voltage in the coil which is converted by an electrical circuit into a DC voltage. The DC voltage is used to control a solid state relay that generates an alarm signal when the value of the DC voltage is less than a preselected value indicating that an open circuit is present in the heating coil.
    Type: Grant
    Filed: August 3, 2004
    Date of Patent: November 27, 2007
    Assignee: Taiwan Semiconductor Manufacturing Co., Ltd.
    Inventor: Jiun-Rong Pai
  • Patent number: 7209048
    Abstract: The present invention is a simple, inexpensive and reliable device for monitoring and alerting of a power disruption to an appliance or a piece of equipment. An audible and/or visual alarm may be generated in the event that a specific or a piece of electrical equipment becomes disconnected from its electrical source. The device for monitoring and alerting of a power disruption may operate from an internal battery in case the electrical power source to the appliance disrupted. Additionally, a power-surge-suppression, a rechargeable battery, and a charger for the battery may make the device more reliable. The remote receiver may receive a broadcasted alarm signal from the monitoring device and then notify a user with a visual and/or audible alarm at a location where the alarm is more likely to be seen and heard.
    Type: Grant
    Filed: March 11, 2004
    Date of Patent: April 24, 2007
    Inventors: Joseph R. Pace, Michelle L. Pace
  • Patent number: 6977591
    Abstract: A method for monitoring a state of a switch is disclosed. The method includes providing a high side driver circuit in communication with a voltage source, activating the high side driver circuit at a first predefined time interval, and sourcing voltage to a resistor in communication with the high side driver circuit at the first predefined time interval. Further, the method monitors the switch at the first predefined time interval, and determines the state of the switch, and deactivates the high side drive at a second predefined time interval.
    Type: Grant
    Filed: May 29, 2002
    Date of Patent: December 20, 2005
    Assignee: Visteon Global Technologies, Inc.
    Inventors: Curtis Elroy Boyer, Benjamin T. Sung
  • Patent number: 6956489
    Abstract: A method for monitoring the condition of an electric current-carrying heating element involving installing the heating element in a location and setting the initial composition Ci of the material as a reference baseline at an initial time Ti corresponding to said installation of the heating element. Data is then collected reflecting the subsequent composition Cs of the heating element material after a subsequent time Ts at the installed location and any change in the material composition of the heating element between Ti and Ts is monitored. An alarm is sent when the change reaches a threshold value indicating a possible failure condition. According to one embodiment, an impedance monitor is provided that calculates and compares impedance at the required levels of accuracy to determine changes in material composition. The impedance monitor, or portions thereof may be embedded within a microcontroller for increased portability and functionality.
    Type: Grant
    Filed: July 17, 2002
    Date of Patent: October 18, 2005
    Assignee: MRL Industries
    Inventors: Kevin B. Peck, Noel H. Johnson, William D. McEntire, Thomas J Berdner
  • Publication number: 20040255694
    Abstract: The invention relates to a measuring device for detecting loads, especially torque, bending moment, and axial force applied to rotating components such as shafts, spindles, and/or pins with which changes if length caused by load are measured and determined in a non-contact manner with aid of at least one resistance strain gauge fixed on the component. For a non-contact feeding of supply energy for the resistance strain gauge and a likewise non-contact transmission of measured values to an evaluation device, an electronic rotor mechanism is provided which is arranged in one or several protective ring(s) (1) that encompasses the resistance strain gauge. For improving accuracy of the measurement and the informative capacity of the measuring results of the measuring device, the protective ring(s) (1) is (are) so arranged on the component that they are supported on one side or are formed deformable with respect to the component.
    Type: Application
    Filed: August 16, 2004
    Publication date: December 23, 2004
    Inventors: Jerry Mackel, Martin Fieweger
  • Patent number: 6445302
    Abstract: A pet training device designed to alert a pet owner that his/her pet would like to enter or exit the home.
    Type: Grant
    Filed: April 12, 2001
    Date of Patent: September 3, 2002
    Inventor: Anthony Vena
  • Patent number: 6294994
    Abstract: An attendance monitoring apparatus is provided for an appliance, such as an electrical appliance, and includes a housing and a motion sensor assembly contained in the housing. A timer assembly is electrically connected to the motion sensor assembly, and an alarm assembly is electrically connected to the timer assembly. The timer assembly is adjustable for selecting a range of predetermined time intervals. Optionally, a current controller is electrically connected to the timer assembly. The current controller controls electric power to the appliance, such as an electric stove. The attendance monitoring apparatus of the invention signals a person with an audible alarm when the person has not attended to the electric stove for a predetermined period of time. Optionally, the attendance monitoring apparatus can turn off electrical power to the stove under these conditions.
    Type: Grant
    Filed: March 7, 2000
    Date of Patent: September 25, 2001
    Inventor: Wendy Hoellerich
  • Patent number: 6130413
    Abstract: A safety device for use in conjunction with an electric cooking stove includes a relay unit having a plug having two live pins and a neutral pin for insertion in a stove receptacle, a receptacle receiving a similar plug of a stove, a relay arrangement for interrupting connections between the live pins of the plug, and corresponding live sockets of the receptacle; and a control unit connected to the relay arrangements, the control unit generating signals to activate said relay arrangement; the relay arrangement is configured to interrupt only one at a time of the connections between the live pins and the live sockets, and the relay arrangement further includes preset switch or jumper to select which of said connections is interrupted.
    Type: Grant
    Filed: March 8, 1999
    Date of Patent: October 10, 2000
    Inventor: Jozef Rak
  • Patent number: 5973605
    Abstract: A combination of circuits is responsive to a respective one of a definite number of operation patterns of a plurality of PTCs, the operation patterns being different therebetween and including a plurality of first patterns each respectively representative of an operating state of a corresponding PTC thermally operated, for providing a signal with a corresponding one of a definite number of signal states representing the operation patterns, respectively, and a common LED is operable by the signal with a respective signal state to provide an identifiable indication relative to an indication by the signal with any other signal state.
    Type: Grant
    Filed: December 19, 1997
    Date of Patent: October 26, 1999
    Assignee: Yazaki Corporation
    Inventor: Hidenori Yamanashi
  • Patent number: 5702624
    Abstract: A heat treatment control system to cure a photoresist that is deposited upon a semiconductor substrate is described. The heat treatment system has a hot plate with a heating element and temperature sensing devices that are in close proximity to the semiconductor substrate. The heat treatment system also has a controlling device that will selectively provide an electrical power source to the heating element to heat the semiconductor wafer. The coupling of the heating element to an electrical power source is determined by an electrical signal from one of the temperature sensing devices that have been conditioned and compared to a set temperature signal to provide an error signal. The controlling device will examine the error signal and adjust the temperature. An over temperature alarm circuit is connected to the second temperature sensing device.
    Type: Grant
    Filed: October 9, 1996
    Date of Patent: December 30, 1997
    Assignee: Taiwan Semiconductors Manfuacturing Company, Ltd
    Inventors: Ching-Wen Liao, Chin-Chuan Kuo, Chi-Kang Peng, Tsun-Ching Lin
  • Patent number: 5448504
    Abstract: A CPU 8 computes differential data of thermal analysis data in a data memory 9a, stores the differential data in a differential data memory 9b, scans secondary differential data, and detects the crossing point of a set differential width as a peak point. The CPU 8 computes second differential data, stores the data in a second differential data memory 9c, scans the second differential data, detects then as a stable area when a part within a set second differential width continues as for as over a set length and the corresponding thermal analysis data has a certain gradient or less. The scanning of the differential data is performed to detect the peak of the differential data as the maximum gradient point. Computation of the transition point and heat of transition having made a peak point, stable area, and maximum gradient point as specified points is performed, and the results are outputted to a CRT 7 or the like.
    Type: Grant
    Filed: May 24, 1993
    Date of Patent: September 5, 1995
    Assignee: Seiko Instruments Inc.
    Inventor: Rintaro Nakatani
  • Patent number: 5182432
    Abstract: A circuit arrangement for a motor vehicle headlight including a reflector and/or a lens, a light source coupled to a voltage providing device (W), at least one electrically conductive heating element (H) mounted on or in an enclosing light-transmissive shield coupled to the voltage source, and a switching-on apparatus (E) for the heating element will, in addition to avoiding a coating and ice build-up, in an uncomplicated and cost effective manner provide a dependable, security-increasing, crack monitoring of the light transmissive shield in that the heating element is electrically coupled with an analyzing apparatus (A) which includes a light-transmissive-shield, crack-monitoring device formed as a current or voltage measuring device.
    Type: Grant
    Filed: May 13, 1991
    Date of Patent: January 26, 1993
    Assignee: Hella KG Hueck & Co.
    Inventors: Ulrich V. Lange, Wolfgang Daub, Friedrich-Karl Wendt
  • Patent number: 5160831
    Abstract: A time-based electrical appliance multi-mode control circuit and indicator arrangement which is connected to a power supply and an on and off switch. Upon turning the switch on, power is simultaneously supplied to the electrical appliance load and to a dual timer circuit. A first timer in the circuit is immediately energized causing a first indicator to represent an on state to the user. After a predetermined length of time, the first timer causes one output to go low, turning off the on state indicator and respectively turning on a ready state indicator. A second timer is then activated for a second predetermined period. At the end of the second period, the ready state indicator is turned off and the standby state indicator is turned on. At the same time, a triac connected to the electrical appliance load is turned off causing the power to the load to be automatically switched off.
    Type: Grant
    Filed: December 6, 1988
    Date of Patent: November 3, 1992
    Assignee: Windmere Corporation
    Inventors: Arnold Thaler, Ivan Saud, P. C. Yip
  • Patent number: 5149209
    Abstract: A hair dryer that includes a case having a handle and a barrel, and a fan positioned in the barrel and coupled to an electric motor for blowing hair through the barrel. An electrical resistance heating element is disposed in the barrel for generating heat to dry hair, and an electrical cord extends from the handle and terminates in a plug adapted to be removably received in a utility outlet for supplying power to the hair dryer. An operator switch is carried by the handle and connected in series with at least the electric motor across the power lines of the cord. An audible alarm is connected across the switch and in series with the motor across the power conductors of the plug and cord, such that placement of the switch in an open condition, with the plug inserted in a utility outlet, results in current flow through the alarm device and generation of an audible alarm signal.
    Type: Grant
    Filed: March 4, 1991
    Date of Patent: September 22, 1992
    Assignee: Jerry O. Lorant
    Inventors: Richard M. Condrey, Jerry O. Lorant
  • Patent number: 5043670
    Abstract: A circuit tester indicates the presence of power at an outlet and the continuity of a resistive load connected to the outlet. The tester is particularly useful as an automotive block heater circuit tester. The tester has a housing with a male end equipped with the prongs conventionally found on a male electrical plug and a female end with a socket of the same configuration as a conventional female electrical outlet. One of the sockets is divided into inner and outer terminals that are sequentially engaged by the mating prong of a male plug as it is inserted into the female end of the tester. A lamp and a resistive circuit are connected into this structure in such a way that when the tester is plugged into a live outlet, the lamp is illuminated brightly. When a male plug is inserted into the female end of the tester, the lamp initially dims to confirm continuity of the load and then brightens as the male plug is fully seated in the socket.
    Type: Grant
    Filed: October 30, 1989
    Date of Patent: August 27, 1991
    Inventors: Rodney H. Isfeld, Brian L. McDougall
  • Patent number: 4972152
    Abstract: An apparatus and method for testing the ignition modules of gas burners is disclosed, and functions without the requirement of a gas feed in the test program. The method involves disconnecting the ignition module from the electrical supply, and from the gas feed, and employing the apparatus of the invention to apply a test voltage to the ignition module, and to various individual components of the system such as the pilot gas valve and main gas valve which are encased in the gas valve, connecting wires, etc. In order to avoid employing gas feed in the test, a simulated gas flame signal is fed to the ignition module under test using a flame simulator device which sends an appropriate signal to the ignitor module. Hence, with the gas feed disconnected, the test method and apparatus of this invention can be used to conduct the test safely, while saving time, and providing a reliable result.
    Type: Grant
    Filed: August 6, 1989
    Date of Patent: November 20, 1990
    Inventor: Edwin R. Finn
  • Patent number: 4935600
    Abstract: A soldering apparatus comprises at least one soldering iron (19) with a heating element (21) and a regulating circuit including a temperature sensor (22) for regulating the working temperature of the soldering iron (19) to a predeterminable desired value (51). The apparatus is characterized by a circuit (45) connected to the soldering unit (19) which at least temporarily stores values corresponding to a time-dependent temperature plot for the soldering iron (19), and also by a monitoring circuit (14) which is connected to the memory circuit. The monitoring circuit monitors during the operation of the soldering iron, from the stored values for the temperature plot, determines whether the temperature undergoes an excursion beneath or above predeterminable upper and lower temperature limits (52, 53) and initiates an alarm signal when the duration of the excursion exceeds a predetermined value.
    Type: Grant
    Filed: November 9, 1988
    Date of Patent: June 19, 1990
    Assignee: Zeva GmbH
    Inventor: Heino Pachschwoll
  • Patent number: 4825199
    Abstract: An improved system for the detection of underloading in an electrical heating circuit where monitoring is available in proximate and remote locations. Circuit monitoring is augmented by control devices which activate alarms in visual or audible form when circuit underloading occurs. This invention has particular application in the plastics molding industry where the control of heat levels within defined ranges must be carefully monitored to ensure process efficacy.
    Type: Grant
    Filed: October 22, 1986
    Date of Patent: April 25, 1989
    Inventor: John E. Antilozi
  • Patent number: 4775913
    Abstract: A control device for controlling the operation of an object of cooking such as a stove or the like. The presence of a user in the area of the stove is detected. When the user is present, the stove operation is enabled. After the user has been absent from the area for a first predetermined time, the stove is temporarily disabled, an again enabled when the user enters the area. If the user is absent from the area of the stove for a second predetermined time, the stove is permanently disabled, so that it cannot again be enabled until manually reset.
    Type: Grant
    Filed: September 2, 1987
    Date of Patent: October 4, 1988
    Inventor: Carl A. Ekblad
  • Patent number: 4774526
    Abstract: A thermal printer with a fault detection circuit for detecting faults in heating elements of the printer includes a print head containing heating elements and a heating circuit for each heating element and a power supply for supplying power to the heating elements. Power is supplied to the print head either directly through one terminal of the power supply or indirectly, during a test mode, through a fault detection circuit which is also connected to the print head. The fault detection circuit includes a constant voltage source, preferably formed of series-connected diodes, through which power flows to the print head. Current passing through the constant voltage source activates a photocoupler having an output the voltage of which determines whether a current is or is not flowing into the print head. A CPU which controls overall operations in the printer monitors the photocoupler and selects either a normal printing mode or a print head test mode.
    Type: Grant
    Filed: September 11, 1986
    Date of Patent: September 27, 1988
    Assignee: Kabushiki Kaisha Sato
    Inventor: Toyozo Ito
  • Patent number: 4751495
    Abstract: A system, utilizing an analog pulsed signal, is for monitoring the condition of a system, by way of illustration, a multi-circuit electrically heat-traced substrate. The system senses the temperature of the substrate at the end of a heat traced circuit, converts the temperature to a pulsed signal, and drives the pulsed signal along the heat tracing to the control and distribution panel for the heat tracing in direct opposition to the AC which powers the heat tracing. A receiver converts the pulsed signal to a digital temperature read-out. Utilization of an analog pulsed signal enables the system to be used in a multi-circuit system without interference or signal mixing from adjacent circuits.
    Type: Grant
    Filed: January 28, 1986
    Date of Patent: June 14, 1988
    Assignee: Raychem Corporation
    Inventor: Richard B. Whitman
  • Patent number: 4727240
    Abstract: An automatic-cutoff electric iron employs two timing cycles for turning off power to the electric iron upon the absence of motion for two different discrete time periods. A motion sensor includes an angle sensor to enable a short timing cycle for cutting off power to the electric iron after the electric iron is motionless with its sole plate in a horizontal orientation. The longer timing cycle is enabled when the electric iron is motionless with its sole plate tilted from the horizontal. The cutoff function is performed by a wedge-shaped actuator driven by a solenoid which releases a spring-urged shaft along with one of the electrical contacts feeding power to the electric iron. The power is turned on by mechanical actuation of the shaft whereby a latch member is engaged behind a cam boss. A manual cutoff is also disclosed.
    Type: Grant
    Filed: August 11, 1986
    Date of Patent: February 23, 1988
    Assignee: Black & Decker Inc.
    Inventors: Daniel J. Provolo, Peter A. Czerner, Michael Singleton, Roman Czernik
  • Patent number: 4639719
    Abstract: An apparatus to monitor a circuit in which an AC voltage source is connected to a plurality of paralleled current consuming loads, such as heaters, including a reactive load in parallel with the current consuming loads at a point in the circuit more distant from the voltage source than any of the current consuming loads being monitored, a phase shift detector connected to the current consuming loads and at a point in the circuit between the voltage source and the nearest current consuming load being monitored, the phase shift detector being sensitive to the shift in current phase induced by the reactor load, and an alarm connected to and actuated by the phase shift detector which provides a warning when the phase shift induced by the reactive load is lost, indicative of a failure in the circuit.
    Type: Grant
    Filed: March 11, 1985
    Date of Patent: January 27, 1987
    Assignee: General Signal Corporation
    Inventors: Thomas W. Pappano, David O. Brown
  • Patent number: 4612498
    Abstract: The specification discloses a computerized monitor for a coreless induction furnace. The monitor includes a first potential transformer connected across the coil and a second potential transformer connected between one end of the coil and an electric ground. The relative location of a ground fault along the length of the coil is approximated by computing the ratio of the transformer outputs. An impedance variation look-up table is included to provide correction factors for the approximated location to compensate for variations in impedance along the length of the coil. The monitor further includes a first current transformer in the coil power line and a second current transformer in the melt bath ground. Internal ground faults are detected by computing the phase difference between the coil and ground currents. A graphic representation of the furnace is also generated to illustrate the location of the ground fault with respect to turns and yokes of the coil.
    Type: Grant
    Filed: April 12, 1985
    Date of Patent: September 16, 1986
    Inventor: Daniel S. Smalley
  • Patent number: 4542284
    Abstract: In combination with an electrical appliance, an automatic warning circuit to warn a user of an electrical hazard wherein the warning circuit comprises a timing circuit responsive to turn-off of the electrical appliance for generating a triggering signal after lapse of a predetermined time period after turn-off thereby to energize an audible alarm. The timing circuit and alarm are useful for warning a user of the appliance of an electrical safety hazard brought out by the appliance being connected to a power line while not being used.
    Type: Grant
    Filed: January 7, 1983
    Date of Patent: September 17, 1985
    Assignee: Windmere Corporation
    Inventors: Arnold Thaler, Lai Kin
  • Patent number: 4539453
    Abstract: A control circuit for a microwave oven with a mechanical switch locking assembly, wherein a cooking start switch is available to turn on after closing a door and is turned off when the door is opened. The control circuit includes a relay for connecting a power source to energize a magnetron, and control means for controlling the relay. The control means enables the relay to connect the power source with the magnetron when the cooking start switch is turned on after connecting the control means with the power source. If the cooking start switch is already turned on prior to connecting the microwave oven to the power source, the operator must first open the microwave oven door, thus opening the start switch, and subsequently closing the door and closing the start switch. This safety procedure encourages the operator to insure that food products are placed in the oven, thus reducing the danger of operating the oven without a load.
    Type: Grant
    Filed: April 6, 1984
    Date of Patent: September 3, 1985
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koichi Miyazaki, Masayuki Aoki
  • Patent number: 4496940
    Abstract: A sensing and indicator system for monitoring multiple electric heating elements connected in three-phase balanced Y circuits in heat reactivatable adsorbent gas fractionators. The system senses a failure induced imbalance, pinpoints the location of the group with the failure and causes a failure indicating alarm to function. The system operates by a sensing circuit including a discharge bulb sensing the failure induced imbalance and causing a conduction of current through the system resulting in the activation of an alarm and the illumination of the gas discharge bulb indicating which of multiple sets of heating elements has failed.
    Type: Grant
    Filed: January 15, 1982
    Date of Patent: January 29, 1985
    Assignee: Pall Corporation
    Inventor: Conrad Christel, Jr.
  • Patent number: 4425490
    Abstract: When a door of a microwave oven is opened during a programmed cooking operation, a door open monitoring circuit provides a door open signal to a microcomputer so that the microcomputer interrupts to execute the programmed cooking operation. A control circuit measures time lapsed from the re-closure of the door to provide the microcomputer with a control signal indicative of whether a cooking switch has been operated within a predetermined period of time after the re-closure of the door. In response to the control signal, the microcomputer executes the remaining programmed cooking operation in case that the cooking switch has been operated within the predetermined period of time or clears it otherwise. The function of the control circuit may be performed by the microcomputer.
    Type: Grant
    Filed: November 18, 1981
    Date of Patent: January 10, 1984
    Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
    Inventors: Sadao Takeda, Yooichi Kyoori
  • Patent number: 4207566
    Abstract: A DC current level detector is provided for monitoring the heater current of a pitot tube. The detector includes a toroidal core defining a bore through which can be passed a line carrying the current to be detected whereby an amount of flux is generated in the core according to the current to be detected. A reference circuit is provided to generate in the core a reference amount of flux against which the first flux is compared in an algebraic combination. An oscillator circuit is inductively coupled to the core to saturate the core in opposite directions. The algebraic difference between the fluxes is employed to generate a signal to operate a relay. The relay is included in a circuit in which are connected a power source and an indicator such as an alarm lamp. The core is of toroidal shape and a casing is provided which houses the core along with the associated circuits and which is provided with an opening corresponding with the bore of the core.
    Type: Grant
    Filed: May 5, 1978
    Date of Patent: June 10, 1980
    Assignee: American Aerospace Controls, Inc.
    Inventors: Robert Gitlin, Evan Mayerhoff
  • Patent number: 4203101
    Abstract: A sensor controlled device for interrupting electric power to a portable electric clothes iron. Two sensors are attached to the handle of the iron. These sense skin contact of the operator and horizontal orientation of the iron. The sensors control circuitry which controls a switching circuit which then controls a power connecting means, such as a relay, for shutting off power to the iron. The switching circuit may also control an electronic timer and an alarm.
    Type: Grant
    Filed: February 28, 1979
    Date of Patent: May 13, 1980
    Inventor: Marvin S. Towsend