Including Bridge Means Patents (Class 219/499)
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Patent number: 4374321Abstract: A copier fuser roll's temperature is accurately maintained by supplying selected half-cycles of current from a power supply to a heater in accordance with signals from a temperature sensor. Each sequential half-cycle is assigned a unique digital input number which accesses a table of digital output numbers having values chosen to correspond to one or more half-cycles. Sensor signals are sampled and digital temperature error numbers, determined by the fuser roll temperature and a desired roll temperature, are derived. The temperature error and output numbers are compared and, whenever a comparison occurs, the corresponding half-cycle of current operates the heater. Thus, depending upon the difference between a desired and the actual roll temperature, variable numbers of evenly spaced complete half-cycles, having a total positive-to-negative ratio approaching unity, are selected.Type: GrantFiled: September 10, 1981Date of Patent: February 15, 1983Assignee: International Business Machines CorporationInventors: Joseph E. Cunningham, Jr., Philip T. Gianos
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Patent number: 4359626Abstract: An electric blanket control effective to deactivate power to the blanket's resistance wire heating circuit, the control having a capacitance detector constructed and adapted to respond to differences in the capacitance of the heating circuit attributable to the presence or absence of the user under the heating wire of the blanket, and a switch responsive to the detector adapted to interrupt power to the heating circuit when the capacitance value of the heating circuit indicates the absence of the user.Type: GrantFiled: September 19, 1980Date of Patent: November 16, 1982Inventor: Bronson Potter
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Patent number: 4348583Abstract: A heating device for use in motor vehicles to rapidly heat combustion chambers, exhaust gas sensors, catalyzers and other associated apparatus. A resistive heating element is connected in series with a low-impedance measuring resistor and a switch across a power source, while a resistance bridge is formed with the aid of two further resistors. The diagonal bridge voltages are compared in a comparator whose output actuates a control circuit which operates the heater switch. The heater switch also provides the power for the comparator. In a first interval, constant current is applied to the heating element, while the current is pulsed during a second time interval. The switch control pulses may be provided by a free-running oscillator or one whose pulses are synchronized with the undulations of the engine starter current.Type: GrantFiled: March 10, 1980Date of Patent: September 7, 1982Assignee: Robert Bosch GmbHInventors: Carsten Bube, Gerd Thiele, Hans Zeller
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Patent number: 4333004Abstract: Sensor and reference wires are directly exposed to the airflow past a vehicle. The wires are electrically conductive, and each has a resistance varying with its temperature. A continuous fixed voltage is passed through the reference wire. A short pulse of greater constant voltage is passed through the sensor wire, the voltage of sufficient magnitude to cause the rapid heating of the sensor wire during the pulse. The resultant rate of heat of the sensor wire, and its final temperature at the end of the pulse, is determined by whether ice or water is on the sensor wire. Circuitry is provided to generate an ice present signal when the difference in current flow during the pulse through the sensor wire and through the reference wire is of such magnitude and sign as to indicate that ice was in contact with the sensor wire. Due to water's heat of fusion, the effect of ice on the sensor wire is readily distinguished from the effect of water.Type: GrantFiled: February 19, 1980Date of Patent: June 1, 1982Assignee: Dataproducts New England, Inc.Inventors: John R. Forgue, Joshua I. Goldberg, Leonard Seide
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Patent number: 4322594Abstract: In a system in which temperature control of a heated region is critical, assurance means of fail-safe nature are provided to guard against improper temperature. An example wherein temperature is critical is: the artificial ventilation of an unconcious patient's lungs by periodically inspired heated gas under pressure. The assurance means includes dual thermometers which sense the actual temperature in the heated region. The actual temperature is compared with the desired temperature to control an electric heater, which, when energized, increase the temperature of the heated region. Furthermore, the temperatures, as sensed by the two thermometers, are compared with each other. If the difference exceeds a predetermined limit, an alarm is given and the heating system is shut down.Type: GrantFiled: June 27, 1980Date of Patent: March 30, 1982Assignee: Respiratory Care, Inc.Inventor: A. Glen Brisson
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Patent number: 4307689Abstract: Switch-controlled apparatus for actuating a power switch to enable application of power from an associated power supply to a heater filament of a glow plug in a diesel engine is disclosed. The filament is one which is heated to a predetermined design temperature when a specified voltage is applied thereto. The power source has a supply voltage greater than the specified voltage of the filament. A switch accessible to an operator of the engine is operable in a first position to prevent the application of the supply voltage to the apparatus, operable in a second position to apply the supply voltage through a first terminal of the apparatus, and operable in a third position to apply the supply voltage through the first terminal and through a second terminal of the apparatus and to a starter for the engine.Type: GrantFiled: August 25, 1980Date of Patent: December 29, 1981Assignee: Champion Spark Plug CompanyInventors: Frank J. Raeske, Robert A. Mahaney, Richard E. Callahan
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Patent number: 4280452Abstract: A device for enhancing the starting of a diesel engine in which the current flow to the glow plugs of the engine during the warm-up time is controlled so as to heat the engine as quickly as possible without damage to the glow plugs. Each glow plug is connected in series with a low value resistance between an output terminal of the relay and one of the battery terminals. Also connected across the output terminal of the relay and the output battery terminal is a series combination of three resistors one of which is in thermal contact with the first resistor. A comparator is connected to the middle points of the Wheatstone bridge circuit thus formed. Relay operating means is provided to open the relay contacts when an output signal is produced by the comparator indicating that the glow plug temperature is sufficiently high. On-off cycling of the current flow to the glow plug is continued until the engine is ready to start.Type: GrantFiled: September 13, 1979Date of Patent: July 28, 1981Assignee: Isuzu Motors Ltd.Inventors: Hideo Kawamura, Takahiko Itou
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Patent number: 4277672Abstract: A control circuit for electrically heatable windshields of automotive vehicles which controls the quantity of heat supplied by the vehicle alternator to the windshield heating element to be adequate for deicing the windshield yet limited to avoid windshield damage and to minimize decoupling time of the alternator from the vehicle battery. The control circuit, which employs an inexpensively installed temperature sensor element that senses ambient temperature, responds to the temperature difference between the ambient and a reference deicing temperature and to the supplied heating power for controlling the duration of the heating period.Type: GrantFiled: December 3, 1979Date of Patent: July 7, 1981Assignee: General Electric CompanyInventor: Dwight V. Jones
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Patent number: 4267434Abstract: In the method and apparatus disclosed herein, heat processing pulsing current is passed, on command, through the conductive backing of an exposed record sheet of heat-processable photosensitive material. The sheet resistance is included as one arm of a bridge which contains a settable comparison resistance in another arm. The cold sheet resistance is sensed and is used by a sample and hold arrangement to set the comparison resistance to a corresponding comparison value which represents the cold sheet resistance multiplied by a preselected percentage. That percentage is one which is known to correspond to the desired processing temperature to which the sheet temperature is to be raised in order to effect the processing of the sheet.Type: GrantFiled: June 14, 1979Date of Patent: May 12, 1981Assignee: Honeywell Inc.Inventor: Gary R. Simpson
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Patent number: 4216371Abstract: Temperature regulating apparatus for the control of temperature within an enclosure including a temperature measuring circuit which measures the temperature within the enclosure and a semiconductor heating circuit for generating heat responsive to the temperature measuring circuit. The temperature measuring circuit includes a resistive bridge with a temperature sensitive element as one of its legs, the output of the bridge being coupled to an amplifier for developing a temperature signal which varies as a function of the temperature within the enclosure. The heating circuit includes a plurality of transistors having their respective collector-emitter paths coupled in series so that a heating current can flow through the collector-emitter paths of all of the transistors. One of the transistors, designated the control transistor, has its base coupled to the output of the amplifier for controlling the heating current by the temperature signal.Type: GrantFiled: February 27, 1979Date of Patent: August 5, 1980Assignee: Compagnie d'Electronique et de Piezoelectricite C.E.P.E.Inventor: Gerard Marotel
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Patent number: 4210823Abstract: A time proportional control means, shown as a temperature control system, utilizes an expanded time constant arrangement with a unidirectional type of digital counter. The control system also utilizes a pulse generating means that is linked to the set point control for the system. Any substantial change of the set point causes the pulse generating means to generate pulses that are used by a pulse responsive circuit to insure that the counter for the system is adjusted to cause the output of the system to correspond with the new set point position.Type: GrantFiled: May 15, 1978Date of Patent: July 1, 1980Assignee: Honeywell Inc.Inventors: John L. Kabat, Marvin D. Nelson
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Patent number: 4191512Abstract: A predetermined pressure ratio is maintained between a foreline and a load port of a vacuum diffusion pump including a bath of oil that is vaporized by a heater. A property of the pump is sensed to derive a signal indicative of the pressure ratio. The signal is compared with a set point value to derive an error signal that controls the amount of power continuously supplied by the heater to the oil bath. The sensed property can be the RMS power supplied by the heater, the heat supplied to the bath, or the density of vaporized fluid in the pump.Type: GrantFiled: August 29, 1977Date of Patent: March 4, 1980Assignee: Varian Associates, Inc.Inventors: Charles D. O'Neal, III, Leo J. Blumle, Marsbed Hablanian
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Patent number: 4184646Abstract: An electropneumatic system to control yarn tension in a yarn winding apparatus in which an electrical resistance strain transducer is associated with the yarn line being wound for generating a signal indicative of tension. This signal regulates a motor driven valve which controls pneumatic pressure used to regulate the winding apparatus. A heat responsive negative feedback control is coupled into the system shunting the electrical resistance strain gauge to provide an anticipating signal to minimize overshoot in the control system.Type: GrantFiled: January 4, 1979Date of Patent: January 22, 1980Assignee: E. I. Du Pont de Nemours and CompanyInventor: John S. Seney
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Patent number: 4182183Abstract: A thermistor circuit, wherein a thermistor, a current-limiting resistor, a complementary resistor and a desired-value variable resistor are connected together in the form of a resistance bridge, where the one diagonal of the resistance bridge is linked to a comparator, and the output of the comparator is connected to a bridge feed point of the other diagonal of the resistance bridge via an RC element consisting of a resistor and a capacitor and via a switching transistor.Type: GrantFiled: May 26, 1978Date of Patent: January 8, 1980Assignee: Boehringer Ingelheim GmbHInventors: Gerhard Funk, Eberhard Weller, Hans-Dietrich Renovanz, Uwe Papendick
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Patent number: 4125845Abstract: An electronic circuit for sensing and controlling the pressure and temperature of ink within an ink jet print head. Ink pressure is monitored by a pair of strain gauges electrically connected into a bridge whose output controls an ink supply valve. Part of that bridge is utilized with additional elements to form a second bridge for monitoring through one of the strain gauges the temperature of the ink jet head, accompanied with a heater of the head that is driven from the temperature signal to maintain the head temperature above a preset temperature.Type: GrantFiled: August 25, 1977Date of Patent: November 14, 1978Assignee: Silonics, Inc.Inventor: Richard G. Stevenson, Jr.
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Patent number: 4110588Abstract: The apparatus includes a cup having a metal base and seated on an insulating support, beneath which is positioned an electrical coil, by means of which heating currents are induced in the metal base of the cup, and this heat is transferred to the fluid which is in the cup, in contact with the metal base. A control circuit is provided including means for generating the heating currents and for selecting the desired temperature. The circuit includes a thermal sensor in heat transfer relation with the cup and coupled to the circuit which controls the operation of the oscillator and the heating of the fluid in the cup to the desired temperature.Type: GrantFiled: August 23, 1976Date of Patent: August 29, 1978Inventor: George E. Holz
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Patent number: 4109134Abstract: A circuit for controlling the power transmitted from an a.c. voltage source by a switching element, particularly a triac, connected in series with a power element, e.g. with the heating element of an image fixing device in an electro(photo)graphic copier, is safeguarded against errant operation by the provision of a checking circuit which comprises means for blocking periodically the transmission of power by the switching element under its normal control and means effective in intervals of the interruption of said transmission by the blocking means for detecting whether power is then being transmitted to the power element and, if it then is, producing a corrective control signal.Type: GrantFiled: August 2, 1976Date of Patent: August 22, 1978Assignee: Oce-van der Grinten N.V.Inventor: Jozef Marie Van Herten
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Patent number: 4109129Abstract: A high frequency energy apparatus for heating an object contained in a heating chamber by high frequency energy which is supplied to the chamber. The temperature of the air in the heating chamber or flowing out thereof is detected. When the temperature of the air reaches a predetermined level, the high frequency energy is controlled. The predetermined level is also changed with the heating time.Type: GrantFiled: December 21, 1976Date of Patent: August 22, 1978Assignee: Hitachi Heating Appliances Co., Ltd.Inventors: Kenji Satoh, Mitsuru Watanabe
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Patent number: 4102298Abstract: A device for supplying heating current to a semiconductor carrier in connection with the thermal separation from a reactance gas, and deposition of semiconductor material upon such a carrier, with the device being operative to supply various voltage-current combinations required to maintain constant temperature of the carrier during the deposition operation, with the current supplied to the carrier being initiated during zero passages of the A.C. supply, and with control of the number of oscillations, per unit of time, of the heating current supplied.Type: GrantFiled: June 10, 1976Date of Patent: July 25, 1978Assignee: Siemens AktiengesellschaftInventors: Wolfgang Dietze, Hans Stut
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Patent number: 4079331Abstract: A condition responsive element, disclosed as a negative temperature coefficient thermistor, operates in conjunction with a bridge circuit to provide a differential input to a special direct current amplifier system. The amplifier system utilizes a combination of positive feedback and negative feedback with the negative feedback always exceeding the level of the positive feedback under steady state operating conditions. The output of the amplifier means further is connected to the lowest energizing potential for the amplifier means through a network that includes a relatively fixed voltage dropping means so that changes in the negative feedback can be made to change the gain of the amplifier system with a minimum of offset or change in calibration of the condition responsive device.Type: GrantFiled: February 9, 1977Date of Patent: March 14, 1978Assignee: Honeywell Inc.Inventors: B. Hubert Pinckaers, Robert T. Ruminsky
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Patent number: 4059204Abstract: In a hot melt adhesive dispensing gun, an electronic circuit is constructed to enable the operator to set a desired temperature to which the glue is heated. This set point is automatically raised a predetermined amount when the glue is flowing in order to compensate for the drop in temperature caused by the loss of heat to the glue and atmosphere.Type: GrantFiled: October 26, 1976Date of Patent: November 22, 1977Assignee: USM CorporationInventors: Robert John Duncan, Richard Montgomery Elliott
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Patent number: 4058254Abstract: The invention relates to a system for measuring or controlling the thermal comfort in spaces used by living beings. In operation an output signal is produced which indicates whether or how much the actual thermal conditions in the space differ from comfort conditions and this output signal may be used to control the comfort conditions in the space. The sensing means takes into account the same conditions as does a living being with respect to convection heat, radiation heat and the heat produced by metabolism. The last mentioned heat might be set in accordance to the activity level of the living being. The surface temperature of the sensing means is compared with a comfort temperature set by a second setting means. If the first setting means is set to a higher heat supply, the second setting means is simultaneously set to a lower comfort temperature and vice versa.Type: GrantFiled: July 11, 1975Date of Patent: November 15, 1977Assignee: Danfoss A/SInventor: Knud Julius Hallgreen
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Patent number: 4056708Abstract: A temperature control assembly for a centrifugal chemical treatment apparatus of the type having a temperature monitoring thermistor and a rotor heater. The heater is energized from a power source through a solid state relay. The thermistor is connected in a temperature Wheatstone bridge which delivers a voltage signal to a digital voltmeter. The digital voltmeter generates a binary output which is compared in a computer with a digital command signal from a keyboard unit. The binary computer output is a programmed function of the difference between the keyboard digital temperature command signal and the voltmeter output. This computer output controls a variable duty cycle multivibrator stage which provides a relay-operating signal whose "on" time is in accordance with the difference between the keyboard command temperature and the digital voltmeter output signal. This operating signal is delivered to the relay via an over-temperature and failure detector receiving signals from the digital voltmeter.Type: GrantFiled: July 22, 1975Date of Patent: November 1, 1977Assignee: Baxter Travenol Laboratories, Inc.Inventors: Charles Soodak, Alexander Gelbman
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Patent number: 4039928Abstract: An operating circuit for a semiconductor switch device of the type that passes electrical current from a source to an electrical load by forward biasing of the semiconductor's control terminal includes a resistance bridge network having in an arm thereof the control terminal to one main terminal circuit of the semiconductor switch, and a bias control for alternately applying forward bias and reverse bias to the control terminal through the bridge network, whereby a voltage is developed across the bridge output during the interval in which the control terminal is reverse biased that is representative of the junction temperature within the semiconductor. The temperature representative voltage is observed, monitored, and used for indication and control.Type: GrantFiled: July 19, 1976Date of Patent: August 2, 1977Assignee: Pertron Controls CorporationInventors: Russell Noftsker, James Kirk Mathews
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Patent number: 4002882Abstract: An energizing circuit for applying maximum electrical power to a heatable element having, at least, a high initial thermal lag. By sensing the resistance of the element, which varies as a function of its temperature, a control voltage is obtained which is used to vary the effectiveness of the heating current so as to provide rapid initial heating without the danger of burn-out. More specifically, the circuit is useful in energizing the glowplug of a model airplane engine.Current pulses are obtained from a storage battery which is connected in series with the glowplug and a semiconductor switch. The switch is turned on and off by a multivibrator to produce a series of current pulses. The duration of each "on" pulse is controlled by a bridge circuit which senses the resistance of the glowplug, which is a function of its temperature, and produces a control voltage which varies the timing of the multivibrator.Type: GrantFiled: March 5, 1975Date of Patent: January 11, 1977Inventor: Charles W. McCutchen
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Patent number: 3965396Abstract: A contactor or switch to an electrically powered unit, such as a motor, is controlled by a condition responsive circuit which may include facilities for changing the response condition of the circuit and/or facilities responsive to several conditions, such as temperature and excessive current.Type: GrantFiled: March 13, 1974Date of Patent: June 22, 1976Assignee: Robertshaw Controls CompanyInventors: Hugh J. Tyler, Dennis E. Newell
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Patent number: 3959692Abstract: Apparatus for controlling the heating of an electric element which repeatedly disconnects the electric element from the heating power supply and connects a resistor in series with the electric element and an electric potential across the series combination, when the voltage drop across the electric element is above a predetermined level, heating power is not reconnected to the electric element. The controller utilizes an adjustable time delay for providing the time period for which heating power is applied to the electric element. After each heating cycle the voltage drop across the electric element is monitored. The length of the monitoring cycle is controlled by a time delay and a voltage sensitive contact connected across the electric element. The monitoring cycle will terminate after a time delay, unless the voltage drop across the electric element is above a predetermined value, in which case it will continue until the voltage drop falls below the predetermined level.Type: GrantFiled: September 18, 1974Date of Patent: May 25, 1976Assignee: Westinghouse Electric CorporationInventor: Donald A. Wetzel
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Patent number: 3955067Abstract: An electronic timing system for timing a frying cycle of a fat frying apparatus includes means for adjusting the timing cycle for variations in the temperature of the fat or oil used in the fryer. The temperature adjusting portion of the system includes a thermistor mounted in a probe immersed in the fat or oil. The thermistor is one leg of a resistance bridge. The bridge is coupled across a comparator which senses the output voltage therefrom and generates an output signal which varies with temperature. This temperature-related output signal is compared in a second comparator with the voltage across a charging capacitor in a resistance-capacitance network. When the charging voltage from the resistance-capacitance network exceeds the temperature-related output signal, the second comparator generates a signal which indicates that the frying cycle is completed.Type: GrantFiled: March 5, 1975Date of Patent: May 4, 1976Assignee: Steak n Shake, Inc.Inventor: Brice Eldridge
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Patent number: 3946198Abstract: A system for controlling the application of heat energy to a ceramic exhaust gas sensor and for linearizing the output signal from the sensor is disclosed. The system compares, electrically, the resistance of a conductive heater winding against a fixed reference and permits a flow of electrical current through the heater whenever the comparison indicates that the temperature of the heater is below the desired level. By periodically establishing a flow of electrical energy through the heater and terminating that flow whenever the heater temperature reaches the desired level, the temperature of the heater may be held at the desired level with great accuracy. In order to periodically reestablish the flow of electrical energy through the heater, the system further provides an oscillator arranged to reestablish current flow through the heater a fixed time period following termination of current flow through the heater.Type: GrantFiled: July 1, 1974Date of Patent: March 23, 1976Assignee: Ford Motor CompanyInventor: Lawrence R. Foote
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Patent number: 3946199Abstract: A temperature control network for a toner fusing device in an electrostatic copier, includes a temperature sensing member located within the toner fusing device generating an electric signal corresponding to the temperature within the toner fusing device to control the electric power supplied to the fusing device heating unit by way of a bridge and differential amplifier circuit to maintain the temperature in the toner fusing device constant, while the electric signal from the temperature sensing member controls other devices in the electrophotographic reproducing apparatus, when the temperature in the fusing device reaches a toner fusible temperature upon starting the operation of the electrostatic copier or when the toner fusing device is cooled to a temperature below a given temperature upon the termination of the operation of the electrostatic copier.Type: GrantFiled: September 23, 1974Date of Patent: March 23, 1976Assignee: Minolta Camera Kabushiki KaishaInventor: Yoshihiro Nakamura
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Patent number: 3946200Abstract: A temperature controller for use with an electrical heater for precisely maintaining the temperature within a system at a selected set point, and employing an improved bridge circuit. A temperature sensitive resistor forms one of the two variable arms of the bridge circuit. The resistor varies in value as a function of temperature exhibiting a temperature coefficient of resistance which is not constant but which varies, decreasing with increasing temperature. The other variable arm, the setting arm, is in the form of a network, including a linear setting resistor and a pair of fixed resistors arranged in a series-shunt circuit. The setting resistor is linearly calibrated in terms of temperature, the series-shunt arrangement providing a composite resistance-set point temperature characteristic which closely corresponds to that of the sensing arm.Type: GrantFiled: February 24, 1975Date of Patent: March 23, 1976Assignee: GCA CorporationInventor: Peter Juodikis
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Patent number: 3943326Abstract: In an electrical soldering iron having a soldering tip which is heatable to a predetermined operating temperature by means of an electrical heater element and in which electrical heating and control circuits are provided to supply electric current to the heater element in response to predetermined changes in temperature of the soldering tip an electrically conducting sensing element is operatively connected with the soldering tip having a resistance which varies directly with changes in its temperature. The heating circuit has a controlled rectifier as a switch and the control circuit is adapted to regulate said controlled rectifier to open and close the heating circuit in response to a predetermined change in the resistance of the sensing element. The control circuit includes a bridge circuit in which a bias compensating diode is connected to compensate for bias of the controlled rectifier.Type: GrantFiled: November 23, 1973Date of Patent: March 9, 1976Assignee: Royel International Pty. Ltd.Inventor: Colin John McKenzie Henry
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Patent number: 3943331Abstract: A temperature control circuit is disclosed for controlling the firing angle of a thyristor such as a silicon controlled rectifier connected in series with a heater across an alternating power source. The control circuit comprises a field effect transistor having its source and drain electrodes connected for firing of the rectifier when the field effect transistor is rendered conductive, and a bias phase control connected to the gate of the field effect transistor for generating a fixed A.C. voltage component which is phase shifted by about 90.degree. with respect to the voltage of the power source together with a temperature dependent D.C. voltage component to control the firing angle of the silicon controlled rectifier in accordance with the heat generated by the heater, the sum of the A.C. and D.C. voltage components being fed to the gate of the field effect transistor. The temperature dependent D.C.Type: GrantFiled: December 6, 1974Date of Patent: March 9, 1976Assignee: Multi-State Devices, Ltd.Inventor: Robert S. Meijer
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Patent number: RE30190Abstract: A surgical cutting instrument includes an electrically heated cutting edge and an automatic control system for maintaining the cutting edge at a constant high temperature for sterilizing the blade, cutting tissue, and cauterizing the incised tissue to reduce hemorrhage from the cut surfaces of the tissues (hemostasis).Type: GrantFiled: February 9, 1976Date of Patent: January 15, 1980Inventor: Robert F. Shaw