EP1775366B1 - Control circuit for fabric treatment devices - Google Patents

Abstract

Circuit for controlling a laundry treatment appliance comprises a motor circuit (20) with an alternating current motor and a door locking circuit (30), both circuits being controlled by a single electronic switch (41).

Description

The invention relates to a control of a device for laundry treatment according to the preamble of claim 1.

Previously used circuits for controlling a laundry treating appliance, such as a washing machine or a spin dryer, include a motor circuit and a door latching circuit, both of which are to be controlled separately. The motor circuit has one through an AC phase gating with a triac-controlled AC collector motor for driving the washing drum. In the motor circuit relays are still connected by the one hand, the direction of rotation of the motor is reversible and on the other hand can interrupt the motor circuit, as it is necessary for example in case of failure, ie an emergency shutdown. Through the door lock circuit, the loading opening or door of the washing machine or spinner is locked with a switch controlled by a PTC bimetallic element during the entire washing or spinning operation in order to prevent any possible endangering of the user by contact with the rotating drum. This PTC bimetallic element is permanently driven with a separate electronic or electromechanical switching element during the washing process.

Such a circuit for controlling a device for laundry treatment with two independent circuits for engine and door lock may, with appropriate interpretation, violate the provisions of European standard EN 60335-1 §19. In this case, additional circuit will be required to monitor the door lock circuit. In addition, 2 independent circuits require an increased material requirement, which runs counter to the absolute requirement for the household appliance industry, namely the cost savings.

The EP 0 702 103 A1 discloses a generic circuit for controlling a washing machine, which controls the motor and the door locking element via a common electronic switching element. A disadvantage of the circuit described, however, is that a shutdown of the engine is only possible via a main relay, which simultaneously interrupts the power supply to the door locking element. Due to the deactivation of the door lock dangerous conditions could result for the user of the washing machine, with renewed activation of the engine.

In recognition of these circumstances, the present invention is therefore based on the problem of providing a circuit for controlling a device for laundry treatment, on the one hand satisfies the need for cost reduction and on the other hand, the European regulations for home appliances with rotating drums and thereby switching off the engine while locking the door allows.

The object is achieved by a circuit for controlling a device for laundry treatment, wherein the circuit comprises a motor circuit with an AC motor and a door lock circuit, wherein the motor circuit and the door lock circuit are controlled via a single common electronic switching element, wherein two electromechanical switches in Motor circuit can be used, which are connected to the winding of the AC motor rotor or with the winding of the AC motor field and interrupt the motor circuit in a first switching state and cause a reversal of the direction of rotation of the AC motor in a second switching state.

Under a device for laundry treatment is a washing machine, a tumble dryer, a spin dryer, etc. understood. The novel combination of the control of the two in their function and control completely different electrical components of a washing machine, namely the washing motor and the door lock, in a single common switching element is made possible by the use of standard, in any circuit for engine control in a washing machine anyway components. In doing so, certain precisely defined sequences must be observed when controlling the two components.

In other words, a circuit for controlling a device for laundry treatment has a motor circuit and a door lock circuit, wherein the motor circuit and the door lock circuit are interconnected such that both circuits are jointly controlled via a single common electronic switching element, that are supplied with power. In addition, two electromechanical switches are used in the motor circuit, which are connected to the winding of the AC motor rotor or to the winding of the AC motor field and interrupt the motor circuit in a first switching state and cause a reversal of direction of the AC motor in a second switching state. An electromechanical switch is understood to mean relays or comparable components.

Due to the omission of a separate switching element for the door lock circuit manufacturing costs are saved and by changing the switching states, the direction of rotation of the AC motor is reversible. In addition, the requirements of the European standard are met in a simple manner.

Due to the different arrangement options for the two electromechanical switches, it is ensured that constructive variations in the wiring of a device for laundry treatment are possible.

In an advantageous development of the door lock circuit is switched through when driving on the single common electronic switching element continuously, the motor circuit is interrupted by at least one electromechanical switch at the same time.

By activating the single common switching element of the door lock circuit is driven and switched continuously, so energized. By activating the single common electronic switching element, the motor circuit is simultaneously activated in addition to the door locking circuit. In the motor circuit is at least one electromechanical switch, through which the motor circuit can be interrupted, so it can be switched off.

The arrangement of at least one electromechanical switch in the motor circuit ensures, despite only a single common electronic switching element for the motor circuit and door lock circuit, that the door lock required for safety reasons is activated before the laundry drum is driven by the AC motor.

In a preferred alternative, the single electronic switching element is a triac or a thyristor.

In a further embodiment, the door lock circuit has a switch and / or a mechanism for locking the door, which can be actuated by PTC bimetallic element.

The fact that the door lock circuit has a controllable by a PTC bimetallic element switch and / or a mechanism for locking the door, it is ensured that after switching off the common electronic switching element, ie the power switch circuit of the door lock circuit, the mechanism for locking the door at least another 30 sec remains locked. In other words, even after only a brief energization of the door lock circuit, the locking mechanism remains closed for at least 30 seconds and the door can not be opened. Until the door could be opened, the laundry drum has come to a standstill without any need for an additional electronic component to control it.

In a further embodiment, the motor circuit in addition to the two electromechanical switches for reversing the direction of rotation of the AC motor and interrupting the motor current to another electromechanical switch for field switching, wherein the electromechanical switch is connected to the field switching with the other winding of the AC motor, as the winding, which is connected to the two electromechanical switches for reversing the direction of rotation and interrupting the motor current.

By further electromechanical switch in the motor circuit ensures that advantageously a field switching is possible.

• Fig. 1 eine Schaltung zur Ansteuerung eines Geräts zur Wäschebehandlung gemäß Stand der Technik,
• Fig. 2 ein zeitabhängiges Schaltzustandsdiagramm gemäß Stand der Technik,
• Fig. 3 eine Schaltung zur Ansteuerung eines Geräts zur Wäschebehandlung gemäß vorliegender Erfindung,
• Fig. 4 ein zeitabhängiges Schaltzustandsdiagramm gemäß vorliegender Erfindung.

An embodiment will be explained in more detail with reference to the drawing and the description below. Show it

• Fig. 1 a circuit for controlling a device for laundry treatment according to the prior art,
• Fig. 2 a time-dependent switching state diagram according to the prior art,
• Fig. 3 a circuit for controlling a device for laundry treatment according to the present invention,
• Fig. 4 a time-dependent switching state diagram according to the present invention.

FIG. 1 shows a known circuit 10 for controlling a washing machine with a motor circuit 20 and a door lock circuit 30. The motor circuit 20 has a triac 21, via which the AC washing motor 22 is driven or energized. The switching on and off of the washing motor takes place exclusively via the triac 21. In the present example, the direction of rotation reversibility of the washing motor 22 is realized in that two relays 23.1 and 23.2 are connected to the rotor winding of the washing motor 22.1. An optional further relay 24 for field switching is arranged in the supply line to the field generating winding of the washing motor 22.2. In addition to the possibility of reversing the direction of rotation of the washing motor 22, the relays 23.1 and 23.2 also enable a power-off circuit of the washing motor 22.1. However, the use of this option is not known from the prior art.

The parallel to the motor circuit 20 connected door lock circuit 30 has a separately switchable triac 31 for driving the Door lock circuit 30 on. Via the triac 31, a PTC bimetallic element 32 is energized, which causes the locking of the washing machine door. By locking the washing machine door, a door contact 33 is closed. The door contact 33 is a backup that the washing machine motor 22 starts only in the case and drives the laundry drum when the door is locked against opening and a risk of injury is excluded.

FIG. 2 FIG. 12 shows the progress of the switching state (activated - ON or OFF - OFF) of the components in the motor circuit 20 and in the door lock circuit 30 as a function of time. The washing program start is indicated by the first vertical line and the washing program end by the second vertical line. The Figures 2a, 2b and 2c refer to components in the motor circuit 20, the Figures 2d and 2e on components of the door lock circuit 30.

A washing program starts by t after a certain time according to Figure 2d triac 31 is activated and remains activated until the end of the washing process. With the end of the washing process, shortly before the end of the watch program, the triac 31 is de-energized, so the bimetallic locking element 32 is no longer energized.

Shortly after activation of the triac 31, the PTC bimetallic element 32 reaches its operating temperature and locks the door lock, as in FIG FIG. 2e shown, even beyond the end of the washing process, to the end of the wash program. Only with the end of the wash program is it again possible to open the washing machine door.

Additional control software for balancing the switching states of the switching elements 21 and 31 ensures that as in FIG. 2a shown, only after the door lock is locked by the PTC bimetallic element 32, the triac 31 is activated and the motor circuit 20 is energized.

FIG. 2b shows that from the activation of the triac 21, the drive of the laundry drum by the washing motor 22 is possible, provided that the relays 23.1 and 23.2 are in such a switching position that the motor 22 is activated ( Figure 2c ). This is always the case with known circuit solutions of the prior art.

An interruption of the washing motor movement ( FIG. 2b ) can be achieved by deactivating the triac 21 (FIG. FIG. 2a ). At the end of the washing process, or with the last deactivation of the triac 21 (FIG. FIG. 2a ) and the washing motor movement ( FIG. 2b ) can be deactivated at the same time the triac 31, which, as mentioned after expiration of at least 30 sec delay time, makes an opening of the washing machine door possible with the end of the washing program.

FIG. 3 shows a circuit 40 for controlling a washing machine according to the present invention with a motor circuit 20 and a door lock circuit 30, wherein both circuits 20 and 30 are energized via a single common electronic switching element 41, such as a triac.

The basic structure of the motor circuit 20 and the door lock circuit 30 corresponds to the respective structure as it is for FIG. 1 has been described. On the description too FIG. 1 is therefore referred to. However, for the purpose of reversibility or engine shutdown, an interconnection of the two relays 23.1 and 23.2 with the winding of the washing motor 22.2 generating the field would also be possible. The optional further relay 24 could also be connected to the rotor winding of the washing motor 22.1. For example, an arrangement is also possible in which a relay is used only to reverse the direction of rotation and a relay is used only to interrupt the motor circuit.

The essential difference between circuit 40 and circuit 10 is that in circuit 40, the door latch circuit 30 is behind the single common electronic switching element 41 with the motor circuit 20 is interconnected. As a result, the motor circuit 20 and the door lock circuit 30 can be energized together by activating only one triac 41 and can also be switched off together.

However, the simultaneous energization of motor circuit 20 and door lock circuit 30 is also decoupled. This decoupling is done by using the relays 23.1 and 23.2 and is an outstanding feature of the present invention. Because while the door lock circuit 30 remains active, the washing motor 22 and thus the drive of the laundry drum by means of the relays 23.1 and 23.2 can be switched off. In this case, the washing machine door would remain locked, for example, for safety reasons, although the motor 22 is temporarily switched off.

In FIG. 4 is the course of the switching state (activated - ON or OFF - OFF) of the components of the circuit 40 after FIG. 3 in the motor circuit 20 and in the door lock circuit 30 as a function of time. The washing program start is indicated by the first vertical line and the washing program end by the second vertical line. FIG. 4a refers to the switching element 41. The Figures 4b and 4c refer to components in the motor circuit 20. FIG. 4d refers to the door lock circuit 30.

A washing program starts by t after a certain time according to FIG. 4a the common triac 41 is driven.

Shortly after activation of the triac 41, the PTC bimetallic element 32 reaches its operating temperature and locks the door lock as in FIG FIG. 4d shown, even beyond the end of the washing process to the end of the wash program. Only now it is again possible to open the washing machine door.

Although simultaneously energized with the door lock circuit 30 and the motor circuit 20, as set FIG. 4b shows the drive of the laundry drum by the washing motor 22 only after some time.

As Figure 4c This is related to the fact that first the relays 23.1 and 23.2 must be switched continuously in order to allow a flow of current through the washing motor 22. In other words, via the circuit of the relays 23.1 and 23.2, the energization of the washing motor 22 can be interrupted.

In contrast to the known circuit ( FIG. 1 ) requires the circuit after FIG. 3 no additional control software that monitors the switching state of two switching elements 21 and 31. Because of the single control 41 both the motor circuit 20 and the PTC bimetallic element 32 are energized in the door lock circuit 30, so that the washing machine door is always securely locked, as long as the control 41 is active.

An interruption of the washing motor movement ( FIG. 4b ) can be achieved by deactivating the triac 41 (FIG. FIG. 4a ) or by interrupting the power supply through the relays 23.1 and 23.2 ( Figure 4c ). However, in order to protect the contacts of the relays 23.1 and 23.2, first of all the motor circuit 20 (together with the door lock circuit 30) is de-energized via the triac 41 ( FIG. 4a ), in this switching state via the relays 23.1 and 23.2 ( Figure 4c ) switched the motor state and then switched on the triac 41, the current flow again ( FIG. 4a ). Consequently, the "switching spark" at the triac 41, but not at the contacts of the relays 23.1 and 23.2.

Due to the trailing lock by the PTC bimetallic element 32 in the door latch circuit 30, the door latch remains open until the end of the wash cycle (FIG. FIG. 4d ), even if the switching element 41 should be temporarily deactivated during the washing process ( FIG. 4a ). With the end of the washing process, shortly before the end of the watch program, the triac 41 is permanently de-energized until the trailing lock releases and allows the door to open safely, since the laundry drum has stopped in the meantime.

If the washing motor 22 must remain switched off during the wash program for a long time, can be energized with the relays 23.1 and 23.2 of the door lock circuit by turning on the triac 41 during the program, without causing the engine is driven ( FIG. 4a ).

Claims (5)

1. Circuit for driving an appliance for treating laundry, the circuit having a motor circuit (20) having an AC motor (22) and a door-locking circuit (30), it being possible for the motor circuit (20) and the door-locking circuit (30) to be driven via a single common electronic switching element (41), characterized in that two electromechanical switches (23.1, 23.2) are used in the motor circuit which are connected to the winding of the AC motor rotor (22.1) or to the winding of the AC motor field (22.2) and interrupt the motor circuit (20) in a first switching state and bring about a reversal of the direction of rotation of the AC motor (22) in a second switching state.
2. Circuit according to Claim 1, characterized in that the door-locking circuit (30) is switched on when driven via the single common electronic switching element (41), it being possible for the motor circuit (20) to be interrupted at the same time by at least one electromechanical switch (23).
3. Circuit according to one of the preceding claims, characterized in that the single electronic switching element (41) is a triac or a thyristor.
4. Circuit according to one of the preceding claims, characterized in that the door-locking circuit (30) has a switch (32) and/or a mechanism for locking the appliance door, which switch or mechanism can be driven by a PTC bimetallic element.
5. Circuit according to one of the preceding claims, characterized in that the motor circuit (20) has, in addition to the two electromechanical switches (23.1, 23.2) for reversing the direction of rotation of the AC motor (22) and for interrupting the motor current, a further electromechanical switch relay (24) for field reversal purposes, the electromechanical switch (24) for field reversal purposes being connected to the respective other winding of the AC motor (22), i.e. not the winding which is connected to the two electromechanical switches (23.1, 23.2) for reversing the direction of rotation and interrupting the motor current.

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