WO2012046198A1 - Door lock device for household appliances - Google Patents

Door lock device for household appliances Download PDF

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Publication number
WO2012046198A1
WO2012046198A1 PCT/IB2011/054391 IB2011054391W WO2012046198A1 WO 2012046198 A1 WO2012046198 A1 WO 2012046198A1 IB 2011054391 W IB2011054391 W IB 2011054391W WO 2012046198 A1 WO2012046198 A1 WO 2012046198A1
Authority
WO
WIPO (PCT)
Prior art keywords
actuator
range
heat
door locking
sensitive device
Prior art date
Application number
PCT/IB2011/054391
Other languages
French (fr)
Other versions
WO2012046198A8 (en
Inventor
Fabrizio Promutico
Camillo Pilla
Gianfranco Proietti
Original Assignee
Bitron S.P.A.
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 Bitron S.P.A. filed Critical Bitron S.P.A.
Priority to EP11781624.9A priority Critical patent/EP2625329B1/en
Priority to KR1020137011447A priority patent/KR101884488B1/en
Priority to CN201180048541.6A priority patent/CN103228835B/en
Publication of WO2012046198A1 publication Critical patent/WO2012046198A1/en
Publication of WO2012046198A8 publication Critical patent/WO2012046198A8/en

Links

Classifications

    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F37/00—Details specific to washing machines covered by groups D06F21/00 - D06F25/00
    • D06F37/42—Safety arrangements, e.g. for stopping rotation of the receptacle upon opening of the casing door
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F39/00—Details of washing machines not specific to a single type of machines covered by groups D06F9/00 - D06F27/00 
    • D06F39/12—Casings; Tubs
    • D06F39/14—Doors or covers; Securing means therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
    • H01F7/18—Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings
    • H01F7/1805—Circuit arrangements for holding the operation of electromagnets or for holding the armature in attracted position with reduced energising current
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F34/00—Details of control systems for washing machines, washer-dryers or laundry dryers
    • D06F34/10—Power supply arrangements, e.g. stand-by circuits

Definitions

  • the present invention relates to a door locking device for household appliances, comprising a solenoid actuator associated with a control circuit.
  • the invention relates to a door locking device in which the aforesaid control circuit comprises
  • a heat-sensitive device connected in series with the actuator and adapted to increase its own impedance, and in particular its resistance, when its temperature exceeds a predetermined level, so as to limit the current flowing in the actuator.
  • FIG. 1 An example of a prior art door locking device of this type is described in EP 1 564 760 A2.
  • a control circuit for the solenoid actuator A of a door locking device is shown in Figure 1 , where it is indicated as a whole by the number 1.
  • the solenoid actuator A is designed to control the position of a mechanical member such as a catch L of the door locking device.
  • the circuit 1 comprises a power source 2, for example the alternating current mains supply, and a switch 3, such as a triac, controlled by an electronic unit ECU.
  • This switch 3 is in series with the actuator A.
  • a heat-sensitive device 4 is also connected in series with the actuator A.
  • this device is a PTC resistor in which the impedance, and in particular the resistance R, increases considerably when the temperature of the device exceeds a predetermined level.
  • Figure 2 of the attached drawings is a qualitative illustration of the linearized characteristic of resistance R (shown on the vertical axis) as a function of the temperature T (shown on the horizontal axis) for a heat-sensitive device of this type: this characteristic shows a resistance which remains substantially constant or only slightly variable at a relatively low value, at 60 ohms for example, in the range from ambient temperature (approximately 25°C) to 100°C or above, whereas for higher temperatures the increase in its value is almost "vertical".
  • PTC resistor of the type shown in Figure 2 The characteristic of a PTC resistor of the type shown in Figure 2 is such that this form of heat-sensitive device can be used effectively to protect the actuator A against over-currents or over-temperatures, but not against any undesired actuation caused by brief pulses (spikes) due to acquired noise or disturbances.
  • US 4 702 619 A and US 3 863 210 A describe electrical sensors of temperature and liquid level respectively, for application in motor vehicles, comprising a combination of PTC and NTC resistors which form a heat-sensitive assembly having a generally decreasing combined resistance-temperature characteristic, which, in particular, decreases at relatively high temperatures.
  • One object of the present invention is to provide a door locking device of the type defined above with a solenoid actuator control circuit such that the aforesaid drawbacks of the prior art solutions can be overcome.
  • the heat-sensitive device is such that: in a first temperature range, substantially corresponding to the ambient operating temperature, it has a high impedance which can limit the current flowing in the actuator to a level below that required for activation;
  • the heat-sensitive device comprises a PTC resistor and an NTC resistor connected in series with each other.
  • this PTC resistor and the associated NTC resistor can be assembled together mechanically so as to form a single component.
  • Figure 1 shows a control circuit for a door locking device comprising a solenoid actuator
  • Figure 3 is a diagram showing the resistance-temperature characteristic of a heat-sensitive device for use in the control circuit of a door locking device according to the present invention
  • Figure 4 is a front view of a heat-sensitive device for a door locking device according to the present invention.
  • FIG. 5 is a sectional view taken along the line V-V of Figure 4.
  • a door locking device comprises a control circuit for the solenoid actuator.
  • This control circuit essentially has the same circuit topology as that of Figure 1.
  • the heat-sensitive device 4 has a distinctive resistance-temperature characteristic of the type which will now be described by way of example with reference to Figure 3.
  • a first temperature range indicated by CI in Figure 3 substantially equal to the ambient operating temperature range, and at higher temperatures which are still acceptable, the heat-sensitive device 4 has a high impedance (resistance R), which can limit the current flowing in the actuator A to a level which is insufficient for the activation of the actuator.
  • the field CI extends to a point close to (and just after) 50°C, and in this range the resistance of the heat-sensitive device 4 is equal to or greater than approximately 200 ohms.
  • the heat-sensitive device 4 has a reduced impedance (resistance) which allows sufficient current to flow in the actuator 4 to cause its activation.
  • the temperature range C2 extends from approximately 55°C to approximately 150°C, and in this range the resistance R of the heat-sensitive device 4 reaches a minimum value Rmin of approximately 60 ohms.
  • the heat-sensitive device 4 has a progressively increasing impedance (resistance), which, as in the case of conventional PTC resistors, can effectively limit the current flowing in the actuator A.
  • the range C3 comprises the temperatures which are essentially greater than approximately 150°C.
  • any spontaneous disturbance, such as a current spike, induced by noise in the circuit will not be sufficiently long-lasting or powerful to heat the heat-sensitive device 4 to a point where its resistance decreases to a value at which the current flowing in the actuator A can cause the activation of the latter.
  • Figures 4 and 5 show a non-limiting exemplary embodiment of a heat-sensitive device 4 for the control circuit of a door locking device according to the invention.
  • the heat-sensitive device 4 comprises a PTC resistor 5, in the form of a chip or cylindrical disc, having a principal face or base on which an NTC resistor 6, also in the form of a cylindrical disc, is connected centrally.
  • this heat-sensitive device 4 has the appearance of a single monolithic component.
  • the PTC resistor 5 comprises a central layer of resistive material 5a (Figure 5), on the flat end faces of which there are first electrode layers 5b, made for example from a nickel-chromium alloy such as Ni80Cr20, and second, outer, electrode layers 5c, made from silver for example.
  • first electrode layers 5b made for example from a nickel-chromium alloy such as Ni80Cr20
  • second, outer, electrode layers 5c made from silver for example.
  • the NTC resistor 6 comprises a layer of resistive material 6a, applied to the central portion of an electrode layer 5 c of the PTC resistor 5.
  • the resistive layer 6 has an electrode layer 6b, also made from silver for example, on its outer face.
  • the ratio between the resistance R25, presented by the heat-sensitive device 4 at 25°C, and the value Rmin is approximately 10, that is to say greater by approximately one order of magnitude than it would be for an ordinary PTC resistor according to the prior art.

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Lock And Its Accessories (AREA)
  • Accessory Devices And Overall Control Thereof (AREA)
  • Magnetically Actuated Valves (AREA)

Abstract

The door locking device comprises a solenoid actuator (A) associated with a control circuit (1) including: a power source (2), a switch (3) interposed between the power source (2) and the actuator (A), and a heat-sensitive device (4) connected in series with the actuator (A) and adapted to increase its own resistance when its temperature exceeds a predetermined level, so as to limit the current flowing in the actuator (A). The heat-sensitive device (4) is such that in a first temperature range (C1), substantially equal to that of the ambient operating temperature, it has a high impedance which can limit the current flowing in the actuator (A) to a level below that required for its activation; in an adjacent second range (C2) of higher temperatures, it has a reduced impedance which allows sufficient current to flow in the actuator (A) to cause its activation; and in a third range (C3) of even higher temperatures, adjacent to the second range (C2), it has a high impedance which can limit the current flowing in the actuator (A).

Description

Door locking device for household appliances
The present invention relates to a door locking device for household appliances, comprising a solenoid actuator associated with a control circuit.
More specifically, the invention relates to a door locking device in which the aforesaid control circuit comprises
a power source,
a switch interposed between the power source and the actuator, and
a heat-sensitive device connected in series with the actuator and adapted to increase its own impedance, and in particular its resistance, when its temperature exceeds a predetermined level, so as to limit the current flowing in the actuator.
An example of a prior art door locking device of this type is described in EP 1 564 760 A2. A control circuit for the solenoid actuator A of a door locking device is shown in Figure 1 , where it is indicated as a whole by the number 1. The solenoid actuator A is designed to control the position of a mechanical member such as a catch L of the door locking device.
The circuit 1 comprises a power source 2, for example the alternating current mains supply, and a switch 3, such as a triac, controlled by an electronic unit ECU. This switch 3 is in series with the actuator A. A heat-sensitive device 4 is also connected in series with the actuator A. According to the prior art, this device is a PTC resistor in which the impedance, and in particular the resistance R, increases considerably when the temperature of the device exceeds a predetermined level.
Figure 2 of the attached drawings is a qualitative illustration of the linearized characteristic of resistance R (shown on the vertical axis) as a function of the temperature T (shown on the horizontal axis) for a heat-sensitive device of this type: this characteristic shows a resistance which remains substantially constant or only slightly variable at a relatively low value, at 60 ohms for example, in the range from ambient temperature (approximately 25°C) to 100°C or above, whereas for higher temperatures the increase in its value is almost "vertical". The characteristic of a PTC resistor of the type shown in Figure 2 is such that this form of heat-sensitive device can be used effectively to protect the actuator A against over-currents or over-temperatures, but not against any undesired actuation caused by brief pulses (spikes) due to acquired noise or disturbances.
US 4 702 619 A and US 3 863 210 A describe electrical sensors of temperature and liquid level respectively, for application in motor vehicles, comprising a combination of PTC and NTC resistors which form a heat-sensitive assembly having a generally decreasing combined resistance-temperature characteristic, which, in particular, decreases at relatively high temperatures.
One object of the present invention is to provide a door locking device of the type defined above with a solenoid actuator control circuit such that the aforesaid drawbacks of the prior art solutions can be overcome.
This and other objects are achieved according to the invention with a door locking device of the type described above, characterized in that the heat-sensitive device is such that: in a first temperature range, substantially corresponding to the ambient operating temperature, it has a high impedance which can limit the current flowing in the actuator to a level below that required for activation;
in an adjacent second range of higher temperatures, it has a reduced impedance which allows sufficient current to flow in the actuator to cause its activation; and
in a third range of even higher temperatures, adjacent to the second range, it has a high impedance which can limit the current flowing in the actuator.
In one embodiment, the heat-sensitive device comprises a PTC resistor and an NTC resistor connected in series with each other. Conveniently, this PTC resistor and the associated NTC resistor can be assembled together mechanically so as to form a single component. Further characteristics and advantages of the invention will be made clear by the following detailed description, provided purely by way of non-limiting example, with reference to the appended drawings, in which:
Figure 1, described above, shows a control circuit for a door locking device comprising a solenoid actuator,
Figure 2, also described above, shows the resistance/temperature characteristic of a prior art PTC resistor;
Figure 3 is a diagram showing the resistance-temperature characteristic of a heat- sensitive device for use in the control circuit of a door locking device according to the present invention;
Figure 4 is a front view of a heat-sensitive device for a door locking device according to the present invention; and
Figure 5 is a sectional view taken along the line V-V of Figure 4. A door locking device according to the present invention comprises a control circuit for the solenoid actuator. This control circuit essentially has the same circuit topology as that of Figure 1. In this circuit of a door lock according to the invention, the heat-sensitive device 4 has a distinctive resistance-temperature characteristic of the type which will now be described by way of example with reference to Figure 3.
In a first temperature range, indicated by CI in Figure 3, substantially equal to the ambient operating temperature range, and at higher temperatures which are still acceptable, the heat-sensitive device 4 has a high impedance (resistance R), which can limit the current flowing in the actuator A to a level which is insufficient for the activation of the actuator. In the example of Figure 3, the field CI extends to a point close to (and just after) 50°C, and in this range the resistance of the heat-sensitive device 4 is equal to or greater than approximately 200 ohms.
In an adjacent second range of higher temperatures, indicated by C2 in Figure 3, the heat- sensitive device 4 has a reduced impedance (resistance) which allows sufficient current to flow in the actuator 4 to cause its activation. In the example shown in Figure 3, the temperature range C2 extends from approximately 55°C to approximately 150°C, and in this range the resistance R of the heat-sensitive device 4 reaches a minimum value Rmin of approximately 60 ohms. In a third range of even higher temperatures, adjacent to the range C2, the heat-sensitive device 4 has a progressively increasing impedance (resistance), which, as in the case of conventional PTC resistors, can effectively limit the current flowing in the actuator A.
In the example shown in Figure 3, the range C3 comprises the temperatures which are essentially greater than approximately 150°C.
In the control circuit of a door locking device according to the invention, any spontaneous disturbance, such as a current spike, induced by noise in the circuit will not be sufficiently long-lasting or powerful to heat the heat-sensitive device 4 to a point where its resistance decreases to a value at which the current flowing in the actuator A can cause the activation of the latter.
Thus there is effective rejection of brief, low-power pulsed disturbances. On the other hand, if the duration and/or power of a pulse flowing in the control circuit 1 are such that the heat-sensitive device 4 is heated sufficiently to raise its temperature to a point in the range C2 of Figure 3, the corresponding reduction of the resistance of the heat- sensitive device 4 enables the actuator A to be activated or energized. If, for any reason, the temperature of the actuator A reaches a point in the temperature range indicated by C3 in Figure 3, the heat-sensitive device 4 will have a correspondingly high impedance (resistance), thus effectively reducing the current flowing in the actuator A. The actuator is thus effectively protected from over-currents and/or over-temperatures. Figures 4 and 5 show a non-limiting exemplary embodiment of a heat-sensitive device 4 for the control circuit of a door locking device according to the invention. In this embodiment, the heat-sensitive device 4 comprises a PTC resistor 5, in the form of a chip or cylindrical disc, having a principal face or base on which an NTC resistor 6, also in the form of a cylindrical disc, is connected centrally.
Consequently, this heat-sensitive device 4 has the appearance of a single monolithic component.
In the illustrated embodiment, the PTC resistor 5 comprises a central layer of resistive material 5a (Figure 5), on the flat end faces of which there are first electrode layers 5b, made for example from a nickel-chromium alloy such as Ni80Cr20, and second, outer, electrode layers 5c, made from silver for example.
The NTC resistor 6 comprises a layer of resistive material 6a, applied to the central portion of an electrode layer 5 c of the PTC resistor 5. The resistive layer 6 has an electrode layer 6b, also made from silver for example, on its outer face.
With reference to Figure 3, the ratio between the resistance R25, presented by the heat- sensitive device 4 at 25°C, and the value Rmin is approximately 10, that is to say greater by approximately one order of magnitude than it would be for an ordinary PTC resistor according to the prior art.
Naturally, the principle of the invention remaining the same, the forms of embodiment and the details of construction may be varied widely with respect to those described and illustrated, which have been given purely by way of non-limiting example, without thereby departing from the scope of the invention as defined by the attached claims.

Claims

1. Door locking device for household appliances, comprising a solenoid actuator (A) associated with a control circuit (1) comprising:
a power source (2),
a switch (3) interposed between the power source (2) and the actuator (A), and a heat-sensitive device (4) connected in series with the actuator (A) and adapted to increase its own impedance, and in particular its resistance, when its temperature exceeds a predetermined level, so as to limit the current flowing in the actuator (A);
the door locking device being characterized in that the heat-sensitive device (4) is such that:
in a first temperature range (CI), substantially equal to that of the ambient operating temperature, it has a high impedance which can limit the current flowing in the actuator (A) to a level below that required for its activation;
in an adjacent second range (C2) of higher temperatures, it has a reduced impedance which allows sufficient current to flow in the actuator (A) to cause its activation; and
in a third range (C3) of even higher temperatures, adjacent to the second range (C2), it has a high impedance which can limit the current flowing in the actuator (A).
2. Door locking device according to Claim 1, in which the heat-sensitive device (4) comprises a PTC resistor (5) and an NTC resistor (6) connected in series with each other.
3. Door locking device according to Claim 2, in which the heat-sensitive device (4) comprises a PTC resistor (5) and an NTC resistor (6) assembled together mechanically so as to form a single component.
4. Door locking device according to any one of the preceding claims, in which
the first temperature range (CI) comprises temperatures up to approximately 55°C, the second temperature range (C2) extends from approximately 55°C to approximately 150°C, and
the third range (C3) comprises temperatures greater than approximately 150°C.
PCT/IB2011/054391 2010-10-05 2011-10-05 Door lock device for household appliances WO2012046198A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP11781624.9A EP2625329B1 (en) 2010-10-05 2011-10-05 Door locking device for household appliances
KR1020137011447A KR101884488B1 (en) 2010-10-05 2011-10-05 Door locking device for household appliances
CN201180048541.6A CN103228835B (en) 2010-10-05 2011-10-05 Door locking device for home appliances

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITTO2010A000814 2010-10-05
ITTO2010A000814A IT1402217B1 (en) 2010-10-05 2010-10-05 CONTROL CIRCUIT FOR AN ELECTRICALLY OPERATED ACTUATOR, IN PARTICULAR AN SOLENOID ACTUATOR

Publications (2)

Publication Number Publication Date
WO2012046198A1 true WO2012046198A1 (en) 2012-04-12
WO2012046198A8 WO2012046198A8 (en) 2012-09-07

Family

ID=43738359

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2011/054391 WO2012046198A1 (en) 2010-10-05 2011-10-05 Door lock device for household appliances

Country Status (5)

Country Link
EP (1) EP2625329B1 (en)
KR (1) KR101884488B1 (en)
CN (1) CN103228835B (en)
IT (1) IT1402217B1 (en)
WO (1) WO2012046198A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3074230A1 (en) * 2017-11-30 2019-05-31 Valeo Systemes De Controle Moteur ELECTROMAGNETIC DIPOSITIVE

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3863210A (en) * 1973-07-30 1975-01-28 Gen Motors Corp Liquid level sensor having an integral ptc and ntc thermistor
US4702619A (en) 1983-03-22 1987-10-27 Standard Telephones And Cables Public Limited Company Temperature sensors
EP0350770A2 (en) 1988-07-14 1990-01-17 TDK Corporation Semiconductive ceramic composition
EP1564760A2 (en) 2004-02-13 2005-08-17 Adams Rite Aerospace, Inc. Solenoid protection method and apparatus
EP1988207A2 (en) * 2007-05-03 2008-11-05 BITRON S.p.A. A door-lock system for a household electrical appliance
WO2009007802A1 (en) 2007-07-10 2009-01-15 Indesit Company S.P.A. Device and method for locking and unlocking the door of a household appliance
GB2460833A (en) * 2008-06-09 2009-12-16 2D Heat Ltd Self-regulating electrical resistance heating elements

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1236884B (en) * 1989-12-18 1993-04-26 Onofrio Rocchitelli DEVICE FOR THE LOCKING OF THE CLOSING AND OPENING VEHICLES OF MACHINES HAVING INTERNAL PARTS SUBJECT TO INERTIAL ROTATION REALIZING THE CLOSING AND OPENING OF THE SWITCH CONTACTS SERIES RESPECTIVELY POSTPONED AND ANTICIPATED TO THE LOCKING OF THE LOCKING
ITTO20030554A1 (en) * 2003-07-17 2005-01-18 Eltek Spa IMPLEMENTATION AND / OR LOCKING DEVICE FOR APPLIANCE APPLIANCES WITH AN IMPROVED IMPLEMENTATION SYSTEM.
ITMI20050297A1 (en) * 2005-02-25 2006-08-26 Elettrotecnica Rold Srl BLOCCOPORTA FOR WASHING MACHINES

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3863210A (en) * 1973-07-30 1975-01-28 Gen Motors Corp Liquid level sensor having an integral ptc and ntc thermistor
US4702619A (en) 1983-03-22 1987-10-27 Standard Telephones And Cables Public Limited Company Temperature sensors
EP0350770A2 (en) 1988-07-14 1990-01-17 TDK Corporation Semiconductive ceramic composition
EP1564760A2 (en) 2004-02-13 2005-08-17 Adams Rite Aerospace, Inc. Solenoid protection method and apparatus
EP1988207A2 (en) * 2007-05-03 2008-11-05 BITRON S.p.A. A door-lock system for a household electrical appliance
WO2009007802A1 (en) 2007-07-10 2009-01-15 Indesit Company S.P.A. Device and method for locking and unlocking the door of a household appliance
GB2460833A (en) * 2008-06-09 2009-12-16 2D Heat Ltd Self-regulating electrical resistance heating elements

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3074230A1 (en) * 2017-11-30 2019-05-31 Valeo Systemes De Controle Moteur ELECTROMAGNETIC DIPOSITIVE

Also Published As

Publication number Publication date
CN103228835B (en) 2016-10-12
EP2625329B1 (en) 2016-04-20
ITTO20100814A1 (en) 2012-04-06
CN103228835A (en) 2013-07-31
IT1402217B1 (en) 2013-08-28
WO2012046198A8 (en) 2012-09-07
EP2625329A1 (en) 2013-08-14
KR101884488B1 (en) 2018-08-30
KR20130143578A (en) 2013-12-31

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