EP0456846A1 - Dispositif électronique de sécurité pour la porte d'un four à micro-ondes - Google Patents

Dispositif électronique de sécurité pour la porte d'un four à micro-ondes Download PDF

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Publication number
EP0456846A1
EP0456846A1 EP90109008A EP90109008A EP0456846A1 EP 0456846 A1 EP0456846 A1 EP 0456846A1 EP 90109008 A EP90109008 A EP 90109008A EP 90109008 A EP90109008 A EP 90109008A EP 0456846 A1 EP0456846 A1 EP 0456846A1
Authority
EP
European Patent Office
Prior art keywords
door
magnetic flux
receiver coil
coil
security device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP90109008A
Other languages
German (de)
English (en)
Other versions
EP0456846B1 (fr
Inventor
Uwe Hartmann
Udo Mai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vogt Electronic AG
Original Assignee
Vogt Electronic AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Vogt Electronic AG filed Critical Vogt Electronic AG
Priority to DE90109008T priority Critical patent/DE59003255D1/de
Publication of EP0456846A1 publication Critical patent/EP0456846A1/fr
Application granted granted Critical
Publication of EP0456846B1 publication Critical patent/EP0456846B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/6414—Aspects relating to the door of the microwave heating apparatus
    • H05B6/6417—Door interlocks of the microwave heating apparatus and related circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24C—DOMESTIC STOVES OR RANGES ; DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION
    • F24C15/00—Details
    • F24C15/02—Doors specially adapted for stoves or ranges
    • F24C15/022—Latches

Definitions

  • the invention relates to an electronic door lock for microwave ovens.
  • the known devices for home use mostly have a fuse consisting of two or more electromechanical switches which are intended to ensure that the microwave radiation is switched off when the door is opened. These switches must work absolutely reliably, which can never be fully guaranteed with mechanically moving components. In addition, it is often possible to close these switches using pointed objects, so that a risk to "curious children" cannot be excluded.
  • the invention has for its object to provide an electronic door lock for microwave ovens, which ensures a much higher level of security than the known door locks with electromechanical switches.
  • the electronic door lock that solves this problem is characterized by the features specified in claim 1.
  • the door security device causes information in the form of a magnetic flux to be routed back from the housing of the microwave oven via the door to be monitored back into the housing by means of a transmission path, and the transmitted and received information is compared and evaluated within the housing, and conclusions are drawn from this State of the transmission path (ie door open or closed) and in the event of danger the magnetron is switched off or cannot be switched on.
  • the main elements of this information are a primary magnetic flux which is emitted from the housing to the door, which causes a secondary magnetic flux which is emitted from the door to the housing and there a voltage which is characteristic of the state of the door (open or closed) in a receiver coil induced that falls off when the door is opened. This induced voltage acts on a control and evaluation circuit which, when this voltage drops, switches off the magnetron or blocks its activation.
  • a magnetically conductive yoke is installed in the door, which returns the primary magnetic flux as a secondary magnetic flux to the receiver coil.
  • Another preferred embodiment of the door lock according to the invention which ensures a particularly high security standard, is in the claim 3 marked.
  • This embodiment makes it possible to achieve a phase shift between the primary magnetic flux and the secondary magnetic flux, so that when the door is open, the attempt to return the primary flux as a secondary flux into the housing as a secondary flux with a magnetically conductive metal part is due to the then different phase relationship between these two flows cannot lead to the magnetron being switched on.
  • the housing 1, 1 'of the microwave oven and its door 5, 5' are only indicated schematically.
  • the magnetron and the power supply of the magnetron have also been omitted because this is known in the art.
  • the door lock according to Figure 1 consists of a U-core 2 built into the housing 1 made of magnetically conductive material with a transmitter winding 3 on one leg and a receiver winding 4 on the other leg.
  • a magnetically conductive yoke 6 which is attached in such a way that when the door 5 is closed it holds the two legs of the U-core 2 bridges.
  • the AC voltage which is induced in the receiver coil 4 by the transmitter winding 3 acted upon by an AC generator G is relatively high.
  • the yoke 6 is moved away from the U core 2 and thus from the windings 3 and 4, the magnetic resistance of the circuit changes and the induced voltage decreases.
  • the control and evaluation circuit 7 connected to the receiver winding 4 is designed such that it obtains information about the state of the door 5 from the change in amplitude of the voltage induced in the receiver coil 4 and generates a switch-off or switch-on blocking signal for the microwave generator.
  • the transmission frequency of the alternating current generator G and the material of the U-core 2 and the yoke 6 are preferably selected in such a way that bridging the legs of the U-core 2 with a material that usually occurs in a household cannot lead to switching on.
  • the door lock shown in Figure 2 with which a particularly high security standard can be achieved, has four rod cores 10 (which could also be U cores), which face each other in pairs in door 5 'and housing 1' and are each surrounded by a coil .
  • the coils located in the housing 1 ' the upper one in the figure is the transmitter coil 11, which is also acted upon by an alternator G', and the lower one is the receiver coil 12 connected to a control and evaluation circuit 15 in the housing 1 ' 1, in the door security device according to FIG.
  • a further receiver coil 13 is arranged on the rod core 10 opposite the transmitter coil 11 and a further transmitter coil 14 on the rod core 10 opposite the receiver coil 12, and these further coils 13, 14 are wound and interconnected such that the primary magnetic flux emitted by the transmitter coil 11 on the housing side is 90 ° out of phase with the secondary magnetic flux generated by the coil 14.
  • the secondary magnetic flux is caused by the fact that the primary magnetic flux induces a voltage in the further receiver coil 13 and, due to the electrical connection of the coils to one another, acts on the further transmitter coil 14, which thus excites the secondary magnetic flux in its core.
  • the control and evaluation circuit 15 is designed so that it can recognize from the amplitude and the phase position of the voltage at the receiver coil 12 with respect to the transmitter coil 11 whether the door 5 'is closed or open (amplitude) and whether someone is trying to use one Pieces of magnetically conductive material to bridge the transmitter coil 11 and the receiver coil 12 (phase position). In any case, when the door is open or when an attempt is made to bridge the coils 11 and 12 with a piece of magnetically conductive material, switching on the microwave and thus endangering persons is reliably prevented.
  • the control and evaluation circuit 7 or 15 can advantageously be integrated in an IC. Integration into the usually available control unit processor or into a control IC for a possibly available switching power supply for the power supply of the magnetron is also possible. In the latter case, it is advantageous to route the control signal for the switching transistor of the switching power supply (ie a signal between the control oscillator and the electronic switch) via the coils of the door fuse. This has the advantage that the switching power supply is always switched off in the event of a fault is, and no operating voltage can reach the magnetron.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
  • Electric Ovens (AREA)
  • Burglar Alarm Systems (AREA)
EP19900109008 1988-12-02 1990-05-14 Dispositif électronique de sécurité pour la porte d'un four à micro-ondes Expired - Lifetime EP0456846B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE90109008T DE59003255D1 (de) 1990-05-14 1990-05-14 Elektronische Türsicherung für Mikrowellenöfen.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19883840650 DE3840650A1 (de) 1988-12-02 1988-12-02 Elektronische tuersicherung fuer mikrowellengeraete

Publications (2)

Publication Number Publication Date
EP0456846A1 true EP0456846A1 (fr) 1991-11-21
EP0456846B1 EP0456846B1 (fr) 1993-10-27

Family

ID=6368333

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900109008 Expired - Lifetime EP0456846B1 (fr) 1988-12-02 1990-05-14 Dispositif électronique de sécurité pour la porte d'un four à micro-ondes

Country Status (2)

Country Link
EP (1) EP0456846B1 (fr)
DE (1) DE3840650A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7009147B1 (en) 2005-01-12 2006-03-07 Maytag Corporation Operational modes for a cooking appliance employing combination cooking technology
CN105737221A (zh) * 2016-05-16 2016-07-06 南宁市茂宏信息技术有限公司 一种防误开门的微波炉
WO2020043438A3 (fr) * 2018-08-27 2020-04-23 BSH Hausgeräte GmbH Appareil à micro-ondes ménager
DE102020203519A1 (de) 2020-03-19 2021-09-23 BSH Hausgeräte GmbH Haushaltsgerät mit Türüberwachungsvorrichtung

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3840650A1 (de) * 1988-12-02 1990-06-07 Vogt Electronic Ag Elektronische tuersicherung fuer mikrowellengeraete
DE3915541C2 (de) * 1989-05-12 1994-02-03 Vogt Electronic Ag Anordnung zur elektronischen Türüberwachung eines Mikrowellenherdes
KR940007232B1 (ko) * 1991-12-31 1994-08-10 대우전자 주식회사 전자렌지의 도어 개폐장치
DE19504574C2 (de) * 1995-02-11 2002-05-02 Miele & Cie Backofen mit einer Türverriegelungseinrichtung bei Mikrowellenbetrieb
DE102010043537A1 (de) * 2010-11-08 2012-05-10 BSH Bosch und Siemens Hausgeräte GmbH Haushaltsgerät

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3816688A (en) * 1972-04-03 1974-06-11 Amana Refrigeration Inc Safety interlock system for microwave ovens
DE3236290A1 (de) * 1982-09-30 1984-04-05 Bosch-Siemens Hausgeräte GmbH, 7000 Stuttgart Vorrichtung zum ueberwachen des schliesszustandes von tueren an mikrowellenoefen
GB2200748A (en) * 1987-01-16 1988-08-10 Europ Microwaves Limited Door alarm system
DE3840650A1 (de) * 1988-12-02 1990-06-07 Vogt Electronic Ag Elektronische tuersicherung fuer mikrowellengeraete

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3816688A (en) * 1972-04-03 1974-06-11 Amana Refrigeration Inc Safety interlock system for microwave ovens
DE3236290A1 (de) * 1982-09-30 1984-04-05 Bosch-Siemens Hausgeräte GmbH, 7000 Stuttgart Vorrichtung zum ueberwachen des schliesszustandes von tueren an mikrowellenoefen
GB2200748A (en) * 1987-01-16 1988-08-10 Europ Microwaves Limited Door alarm system
DE3840650A1 (de) * 1988-12-02 1990-06-07 Vogt Electronic Ag Elektronische tuersicherung fuer mikrowellengeraete

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7009147B1 (en) 2005-01-12 2006-03-07 Maytag Corporation Operational modes for a cooking appliance employing combination cooking technology
CN105737221A (zh) * 2016-05-16 2016-07-06 南宁市茂宏信息技术有限公司 一种防误开门的微波炉
WO2020043438A3 (fr) * 2018-08-27 2020-04-23 BSH Hausgeräte GmbH Appareil à micro-ondes ménager
GB2591656A (en) * 2018-08-27 2021-08-04 Bsh Hausgeraete Gmbh Household microwave device
GB2591656B (en) * 2018-08-27 2022-07-06 Bsh Hausgeraete Gmbh Domestic microwave appliance
DE102020203519A1 (de) 2020-03-19 2021-09-23 BSH Hausgeräte GmbH Haushaltsgerät mit Türüberwachungsvorrichtung
WO2021185576A1 (fr) 2020-03-19 2021-09-23 BSH Hausgeräte GmbH Appareil électroménager comportant un dispositif de surveillance de porte
US12501524B2 (en) 2020-03-19 2025-12-16 BSH Hausgeräte GmbH Domestic appliance having a door monitoring device

Also Published As

Publication number Publication date
DE3840650C2 (fr) 1993-06-17
EP0456846B1 (fr) 1993-10-27
DE3840650A1 (de) 1990-06-07

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