DE2122879A1 - Safety device of a washing machine - Google Patents

Description

Safety device of a washing machine.

The invention relates to a safety device for use in a washing machine, in particular a washing machine with a DC motor and a DC power supply circuit for the motor, which circuit directly from the AC mains is fed, and with a programming device, one with the direct current motor in series immersion element and a thermostat for Control the bath temperature.

It is known to have a DC motor in a washing machine a permanent magnet fed in series with a resistor. This resistance has a sufficient value to cope with the load on the engine Desire to increase without the permissible in the engine Current intensity is exceeded. If the engine is under heavy load, e.g. when washing, shows it rotates slowly and takes a high intensity current so that the energy dissipated in the resistor is high. This energy can e.g. used for heating or for maintaining the bath temperature. On the other hand the motor requires only a low load when the load is low, e.g. when centrifuging Power, as a result of which the current flowing through the series resistor is low and causes significantly less heating than when operating under maximum load. This series resistance protects the motor and prevents any overload, especially when locking, but the temperature of the bath increases and can exceed the predetermined temperature during the washing process.

It is known to use a thermostat to interrupt the heating to be used when the temperature predetermined for the washing process is reached. In the known machines, the sensitive part of the thermostat is in the wall of the bucket and controls the heating of the bath. The received The specification relates to the bath used for washing and its temperature range is substantial. Excessive heating of the resistor is only possible after one relatively long time and transmitted too late to the possible brought about Avoid disadvantage # e.

The electrical circuit of a washing machine should be relatively can transmit high power. the Use of high-performance heating elements, whose heating time is relatively short, and the use of a DC motor, especially in the washing process, bring such momentary electrical power when starting the engine with it that numerous household appliances fail -are to withstand the current surge so that the fuses blow. It is therefore particularly important to temper it, especially during the heating period of the engine. Such a method in which the mechanical action of the Machine is interrupted while the washing process is hot, is off known from French patents 1,184,391 and 1,188,674. After the latter Patent specification, the mechanical washing performance can only take place when the bath is the has reached the desired temperature.

The timer contains a lock that is only under the control of the thermostat can be corrected. This locking device forms a Protection against an effect when dry, otherwise when the on the thermostat indicated temperature has been reached, despite the absence of water in the ashtray the heating circuit interrupted, the washing motor started and the heating circuit is not closed again before the retirement that causes the heating has exceeded in the opposite direction after the action of the timer is. Although this device provides protection against the risk of overheating without Water results, the control of the movements after heating forms a certain Disadvantage. It is beneficial without A washing process that is just as fast maintain as at the required temperature of the bath, the laundry temporarily to stir. This possibility does not exist with the device according to the above-mentioned one Patent specification.

The device according to the invention overcomes the various disadvantages the devices according to the aforementioned patents and also enables: - a protection in case of heating without water while the machine is drummed with shorter or longer time intervals during the temperature rise of the washing bath Can perform washing and / or rinsing movements.

- a protection of the motor in case of blocking, e.g. if a cloth falls between the drum and the bucket, - for the electrical supply of the machine Use circuits of relatively low power while even executing the washing and »or rinsing movements a lower heating power is available, so that the cooling of the bath is avoided.

The protective device of a washing machine according to the invention and especially for a washing machine with a DC motor and a DC supply circuit for the motor, which circuit is fed directly from the AC network, with a timer, an immersion element connected in series with the motor and a thermostat for controlling the temperature of the bath is characterized by that they have a first supply terminal, a thermostat contact in series, on the one hand, with a circle parallel to the supply circuit of the DC motor, which parallel circuit contains at least one timer contact, and on the other hand with the supply circuit of the DC motor, a thermal with the sensitive part the thermostat connected immersion element and the second supply terminal contains.

In a further embodiment, the first AC supply terminal is a first circuit with a first contact of the timer and a second Circuit with a contact independent of the timer, while the others Ends of these two circles have a thermostatic clamp in common.

On the other hand, the first and second contacts of the timer mechanically connected in opposite directions so that one of the contacts is open when the second is closed. These two contacts can be through the the same cams of the time switch are switched in opposite directions.

According to a further feature of the invention, the immersion element is thermal with the sensitive part of the thermostat through a thermal parallel connection tied together.

The invention is explained in more detail with reference to the accompanying drawing.

Fig. 1 shows the device according to the invention in the simplest Embodiment.

The motor M for driving the drum of a washing machine is over a controlled rectifier bridge (Diodes and thyristors) 10 fed from the AC network.

The engine speed is regulated by a control unit 9, which influences the supply of the motor through the thyristors. The engine is in Series with, on the one hand, a thermostat 8 with two contacts 81 and 82 and on the other hand a heating element 6. A circuit connected in parallel to the motor contains a contact 4, which forms part of the reversing switch. The circuit diagram is based on Fig. 2 described individually.

Fig. 2 shows a preferred embodiment.

In the washing machine, part of which is shown in the circuit in FIG the electrical power is supplied from the 220 V alternating current network. Between two supply terminals is the winding of an electrical switch 1 in series Fill and the contacts of the pressure gauge 2 are switched on. For the sake of simplicity only two contacts 21 and 22 are shown, the contact 21 being the empty bucket and contact 22 corresponds to the full bucket. It is believed that the usual Pressure gauge allows different levels depending on the selected washing program or to check the order of the program.

In the circuit diagram, the thermostat 8 is in the simplest embodiment shown: two contacts, a cold contact 82 and a hot contact 81. In A known machine allows the thermostat to set different temperatures choose, but using the same in this diagram does not cause any difficulties with himself.

The motor is powered by a diode and thyristor bridge from the alternating current network fed; its speed is controlled by a thyristor control the level of the resistor in series with the motor and the speed is regulated depending on the desired effect.

The device for reversing the direction of rotation of the motor is not shown; it is arranged close to the direct current supply with the exception of the contact 5.

At the beginning of a wash cycle, the water is supplied through the Pressure measuring device 2 in state 21 (empty bucket) whereupon the solenoid valve 1 is activated and when the water has reached the predetermined level, the contact tilts of the pressure measuring device in the state 22, whereby the supply of the magnetic switch winding interrupted and filling is stopped.

At this moment contact 3 of the timer is opened this contact is used to rotate the drum during spinning and emptying only in Absence of water used and it shorts the pressure gauge come here.

Contact 4 is closed.

Contacts 3 and 4 are in opposite directions on the the same control cam attached: they can never be closed together, but they can be open at the same time. This arrangement serves to prevent the Heat when the bucket is empty and form one usual protection.

During the washing process, the contact of the thermostat 8 is able 82, which corresponds to the cold state, and contact 3 is open and 4 is closed. The motor rotates when contact 5 of the reversing switch is opened; in this case the motor is fed via the immersion element 6 and the whole The current flowing through is about 5 A. The one dissipated by the 2 kW immersion element Power is only 625 W.

The motor is stopped by closing contact 5. The diving element is then fed directly from the grid and the dissipated power of 2 kW gives the heating.

When the desired temperature is reached, the thermostat cuts out the contact 82 and arrives at the state 81. When returning to the state 81 delivers the thermostat emits an impulse that activates the timer, which then switches on the Contact 4 for the wash cycle opens. After a certain time, about 2 minutes, is the bath cooled sufficiently (by about 5 to 70) to make the thermostat contact 82 to be set again. The engine is started again and the immersion element 6 dissipates sufficient power (625 W) to maintain the temperature. The duration of the washing process is determined by the selected program.

During the spinning process or when emptying (effect without water) contact 3 is closed by the timer (contact 4 is then open); the engine will then fed via the immersion element. The one from the latter dissipated power is not enough to cause dangerous heating, even more so in the second two cases - spinning or emptying, during the largest Part of the process is water on the bottom of the bucket (where the immersion element is present is) is present.

The protective device according to the figure is intended in one and / or the other address the two following cases: 1. the pressure measuring device is defective and short-circuited, the washing process then takes place without water; 2. The drum is during emptying (empty bucket) and locked during spinning.

The operational safety brought about by the device according to the invention when washing can be explained as follows.

The cycle can start in the normal way (if the machine does not have a Contains protective device for the water or if this device is defective) but the immersion member 6 is brought to a high temperature almost immediately. The piston, which is mechanically and thermally connected to the immersion element, acts very quickly on the control of the reversing switch of the thermostat 8 and the contact 82 is opened and 81 is closed, transmitting a pulse that controls the timer for the rest of the cycle. The wash cycle continues without damage the laundry or the other elements of the machine (especially the motor).

When the laundry is taken out, it turns out that the Laundry is still dry and dirty, but nothing further is seen.

The motor can be locked if a piece of laundry is in between the drum and the wall of the bucket.

There are no disadvantages to locking the motor during the washing process with itself, since there is water in the bucket; the washing bath is then set to the predetermined one Temperature heated. When the machine steps to emptying or spinning, the circuit is traversed by a relatively high current, so that the Immersion element provides sufficient power to keep the thermostat 8 in the hot Skip state 81 and stop the engine. After a certain amount of time, when the temperature has dropped, the thermostat returns to state 82, whereupon the motor is fed again and the immersion element is heated, and over the thermostat stops the engine, which start and stop alternation continues until End of cycle continues.

The use of a DC motor with a series resistor, which is formed by the immersion element, thus made possible by the arrangement the sensitive part of the thermostat on the one connected in series with the engine Resistance, as a result of almost complete safety when washing without water a defect in the pressure gauge or a blocking of the motor when emptying and To achieve spin. The individual control of the contacts 3 and 4 prevents e crazy complete Heating during emptying and spinning, i.e. when the bucket is empty and automatically prevents any wrong action.

Another advantage of the invention is that the performance, which is controlled by the power control circuit of the motor, extremely low is because the heating is only switched on when the engine is at a standstill. This makes possible, to use a regulation by phase control without causing inadmissible disturbances in the alternating current network.

Claims (6)

P A T E N T A N 5 P R U C H E Protection device for a washing machine with a DC motor and a DC power supply circuit for the motor, which circuit directly from the AC mains is fed, and with a programming device, a diving element in series with the DC motor and a thermostat to control the temperature of the bath, characterized in that the device has a first supply terminal, a thermostat contact in series, on the one hand, with a circuit parallel to the DC supply circuit of the motor, which parallel circuit has at least one programming contact, on the other hand with the direct current supply circuit of the motor, one thermally with the sensitive one Part of the thermostat-connected immersion element and the second supply terminal contains. 2. Protection device according to claim 1, characterized in that the first AC supply terminal to a first circuit with a first timer contact and a second circuit with a contact independent of the timer in common is, while the other ends of these two circles are a common thermostat contact terminal exhibit. 3. Protection device according to claim 2, characterized in that the first and second contacts of the timer mechanically in opposite directions Directions are linked so that one of the contacts is open when the second is closed. 4. Protection device according to claim 3, characterized in that that the first and the second contact through the same cam of the timer in opposite directions can be controlled. 5. Protection device according to one of the preceding claims, characterized characterized in that the immersion element is thermally connected to the sensitive part of the thermostat is connected by a thermal parallel connection. 6. Protection device according to one of the preceding claims for a Washing machine whose motor feed circuit has a reversing switch that periodically reverses the direction of rotation of the motor during the washing process, as <hircli marked <'hnet, that the parallel circuit with at least one timer contact has an additional Has contact of the reversing switch in series with this second switch contact, which additional contact is closed while the motor is at a standstill. L e r s e i t e