DE69519255T2 - Multi-program washing machine with an electromechanical switching mechanism and a digital control unit - Google Patents

Description

The invention relates to a multi-program washing machine with an electromechanical program or programming device and an electronic microcontroller for controlling the operation of a motor provided in the machine during the washing programs, wherein the programming device transmits control codes to the microcontroller.

Normally, all domestic washing machines for washing clothes have an electromechanical programming device or a washing program control, which essentially consists of an electric motor that operates a camshaft via a gear box, the cams in turn controlling the machine elements (inlet solenoid valve, waste water pump, heating device, etc.) by closing or opening a series of electrical contacts.

Today, many clothes washing machines use, in addition to the traditional electromechanical programming device, an electronic device to control the speed of the machine's main motor so that its rotation speed can be varied within the required wide range (washing, fluffing, spin speed, etc.). Often the electronic device is a digital microcontroller.

While the electronic control device is versatile and easy to program, but loses the stored data in the event of a power failure, the conventional electromechanical programming device is not very flexible and cannot be easily changed, but has the great advantage of a mechanical memory that does not cause problems in the event of a power failure.

As is well known, the washing result in household washing machines is achieved by mechanical action, chemical action and heat action. All three actions can be brought about either simultaneously or separately during the various program phases or washing cycles.

The mechanical action is achieved by moving the laundry contained in the drum in the washing liquid contained in the washing tub. The chemical action is achieved by concentrating certain amounts of detergent and detergent additives in an appropriate amount of washing liquid. The heat effect is based on the different temperatures of the washing liquid in the washing machine, taking into account that a hot liquid can remove dirt better than a cold liquid. It is obvious that in determining all three effects, the properties of the textiles to be washed should also be taken into account.

For this reason, modern washing machines have been developed that provide various washing programs controlled by a programming device, which the user can select according to his or her specific needs, depending on the degree and type of soiling and the properties of the textiles to be washed.

The conventional electromechanical programming devices of household washing machines generally offer three basic washing programs:

- a washing programme for normal laundry, for example cotton textiles, providing a liquid level of approximately 7 to 8 litres in the washing tub, vigorous movement of the laundry, high temperatures and a high spin speed;

- a washing programme for synthetic fabrics using essentially the same amount of water as the first programme, but characterised by less vigorous agitation of the laundry, the absence of a pre-wash cycle, low temperatures and an average spin speed;

- a wool washing program in which a water level of around 20 litres is provided in the tub and the laundry is gently agitated, low temperatures are used and the clothes are spun slowly.

Special washing programs are derived from these three basic washing programs and can currently be designed from any basic washing program. These special washing programs are merely partial programs that only include a part of the basic washing program (program without pre-wash, only rinse cycle, only spin cycle, etc.), so that the washing machine on the current market can normally offer 12 or more programs.

However, there is a need for additional special washing programs, such as a delicate wash program or a curtain wash program, which, even when dealing with synthetic fabrics, require more water - such as for Wool, a special movement and no spinning are required.

When integrating such gentle washing programs into the electromechanical programming device, costly changes are necessary. In addition, two options are required because, for commercial reasons, not all machines should have the same programs, so either two different programming devices would have to be used or a very complicated programming device would have to be built into all machines, which would make the cheaper machines more expensive in particular.

From US-A-5,150,489 a washing machine is known which has an electromechanical programming device for selecting several washing programs and an electronic microcontroller for controlling a motor in the machine during these programs, whereby the programming device transmits control codes to the microcontroller and these codes can be modified after switching on a switch between the programming device and the microcontroller.

Therefore, the object of the invention is to provide a washing machine with complete additional programs to the three basic washing programs, whereby no costly changes are required and in particular the electromechanical programming device does not have to be changed.

The invention solves the above-mentioned and other problems, which will become apparent from the following description, by means of a multi-program washing machine with the characterizing features of claim 1.

Further objects and advantages of the invention will become apparent from the following description and the accompanying drawings, which are given for illustrative purposes only and are not to be understood as limiting. They show:

Fig. 1: a simplified block diagram of the operation of the machine according to the invention;

Fig. 2: a simplified circuit diagram of the programming device of the machine in a conceivable embodiment of the invention;

Fig. 3: a simplified block diagram of the machine’s operation according to another embodiment of the invention;

Fig. 4: a comparison, purely by way of example, between two tables listing the engine speed sequence for the basic synthetic wash program and for the program according to the invention.

In Fig. 1, T designates an electromechanical timer providing three basic washing programs (cotton, synthetics, wool); ME designates an electronic digital module controlling a washing motor M. The ME module contains an electronic microcontroller MP with a counter or built-in clock - CLOCK - connected to a permanent storage device ROM and a read/write memory designated RAM. The permanent storage device ROM contains the operating programs of the washing machine motor M, while the RAM is used to store operating parameters. TAC designates a tachometer dynamo, i.e. a device capable of generating a signal representing the speed reached by the motor M. P1 and P2 designate two water level sensors, for example two pressure switches, for controlling the liquid level in the washing tub. EVF designates a solenoid valve for the water supply to the washing tub. Finally, A designates a button that is located between the connecting lines from the timer T to the ME module and to the pressure switches P1 and P2.

The machine shown in Fig. 1 has the following workflow:

In normal operation, i.e. without pressing button A, the operator fills the laundry into the washing drum, selects the desired washing program (e.g. the synthetic program) by operating the timer and switches the machine on using the on/off switch. The machine carries out the selected washing program in the known manner, which does not need to be explained further. For a better understanding of the invention, it should be noted that the program or programming device or the timer T transmits binary-coded signals to the module ME during the washing program. Using these binary codes, the microcontroller MP determines the motor operating programs for the various washing steps in its ROM memory. In other words, the microcontroller MP knows, based on these binary codes, how the motor M should work, i.e. when the drum should be rotated and when it should stop, how fast it should rotate during washing and spinning, etc.

Button A is in fact a control used to modify a basic wash program selected by the timer by modifying the binary codes transmitted by the timer to the ME module. In the example of Fig. 1, button A also activates pushbuttons P1 and P2 to modify the amount of liquid in the washing machine tub compared to the basic wash program.

When button A is pressed, the machine works as follows: The operator selects the synthetics program, loads the machine with the items to be washed according to this special or delicate program (e.g. curtains), press button A and switch the machine on. As already mentioned, by pressing button A two changes are possible in the synthetics wash program, whereby the program sequence remains unchanged:

- On the one hand, the washer fluid level is changed by operating the pressure switches P1 and P2. In practice, switch A switches off the pressure switch for the first water level, so that the solenoid valve EVF allows more water to flow in than in the synthetic wash program;

- On the other hand, the binary codes transmitted by the timer T to the module ME are modified. Therefore, based on the codes received from the timer, the microcontroller MP searches the ROM for the appropriate program to control the motor M differently from the synthetic wash program.

It is obvious how the synthetic program can be changed using the A key so that a special program with very different features is obtained.

Fig. 2 shows a simplified circuit diagram of the washing machine programming device according to another embodiment of the invention.

In Fig. 2, the symbols used for washing machine circuit diagrams have been adopted. For the sake of simplicity, only the circuit sections essential to the invention are described.

As in Fig. 1, the program setup shown in Fig. 2 consists of:

- a standard electromechanical timer with three basic washing programs (cotton, synthetics, wool),

- an electronic digital module that controls the washing motor and is connected to the timer via four wires through which it receives a 4-bit binary code.

In Fig. 2, I1 indicates the on/off switch of the machine, while 12 indicates the spin stop button. 13 indicates the "economy program" (half load) and A is the button for executing the special program according to the invention, i.e. the "gentle program for particularly delicate fabrics" or the "curtain washing program". The timer has four sets of changeover contacts, designated by the symbols A₁-A₁₂, B₁-B₁₂, C₁-C₁₂, D₁-D₁₂. These contacts are controlled by a cam device which is set in rotation by the driver motor MT.

The timer also controls the two pressure switches P1 (first water level) and P2 (second water level), the inlet solenoid valve EVF, the waste water pump and the heating element RR for heating the washing liquid in the washing tub.

The electronic module ME has a first set of terminals (power connections) with which the module is connected to the windings of the washing motor (terminals 2, 3, 4) and to the power supply (terminals 6, 7), and a second set of terminals (signal contacts) through which the module is connected to the pressure switches (terminals 9 to 17), to the tachometer TAC (terminals 19 to 20) and to the timer (code contacts 13, 14, 15, 16; spin contact 18).

According to Fig. 1, the ME module contains a microcontroller, i.e. a central control unit (MP) connected to a read-only memory (ROM) containing the engine operating programs and to a read/write memory (RAM) for storing the working parameters. The module also contains some power switches (TRIAC) for controlling the washing motor.

Via terminals 13, 14, 15, 16, the timer sends a 4-bit code to the module indicating the way in which the motor is to be controlled during the individual wash cycles, in particular the rotation speed (rpm) and the work/standstill ratio (duty cycle), i.e. the type of movement (e.g. 80% if the motor runs for 12 seconds instead of 15 seconds).

The central unit of the ME module looks up the corresponding program in the ROM memory based on the code received from the timer; for example, code 1000 means "engine stopped", code 1001 means a speed of 55 min-1, a duty cycle of 80%, etc.

According to the invention, button A comprises two parts, i.e. 4 contacts which are closed in pairs when the button is pressed. Button A is arranged between the circuit of the two pushbuttons P1 and P2 on the one hand and between the timer circuit and terminals 13, 13, 15, 16 of the electronic module ME on the other hand (more precisely, in the circuit diagram, between contact B1 of the timer and terminal 15 of the electronic module ME).

When button A is pressed, its first section maintains the information for the EVF inlet solenoid valve (via contacts 21-22 of P2) to allow water to be inlet even after the position of the first pressure switch P1 has changed (from contact 12 to contact 14), so that water continues to flow into the tub even when the washing motor is running, as long as the second pressure switch P2 is not activated. On the other hand, the second section of button A adds a bit to the code sent by the timer to the module (e.g. from 1001 to 1101), allowing a different program, i.e. a reduction in the washing speed (e.g. from 55 to 35 min-1) and the movement/stop ratio (e.g. from 80% to 20%). Compared to the normal basic washing program (the synthetic program in this case), we can therefore achieve a reduced mechanical washing effect and a reduced creasing effect thanks to the lower speed, the shorter motor running time and the larger amount of water flowing in. This means that the fabrics do not crease and subsequent ironing is not necessary. Without changing the electromechanical timer in any way, a fourth basic washing program can be entered by simply pressing a button (A), which in this case is a gentle program suitable for washing curtains, for example.

Fig. 4 shows, purely as an example, a comparison between two tables listing the sequence of motor movement steps of the basic synthetic washing program and the program according to the invention, which is suitable for particularly delicate fabrics or curtains. In these tables, the first column shows the start of the phase provided for after the selected program, the second column shows the change in the water level in the wash tub (changeable from the first to the second water level), in the third column the timer step (indicating the progress of the wash cycle) in which preset functions indicated in the fourth column are carried out and, finally, in the fifth column the code transmitted by the timer to the ME electronic module to control the washing motor and carry out the function indicated in the fourth column. The abbreviations used in the tables of Fig. 4 have the following meaning:

Car. = Water inlet into the wash tub

Lav.A = washing at 55 min-1, movement 53% (e.g. 8 minutes movement /7 minutes standstill)

Lav.B = washing at 35 min-1, movement 20% (e.g. 3 minutes movement /12 minutes standstill)

Lav.C = washing at 55 min-1, agitation 80% (e.g. 12 minutes agitation/3 minutes rest)

Risc. = Heating of the washing liquid

Scar. = Water outlet from the wash tub

Stop H₂O = Motor stop when there is water in the wash tub

Distr. = Loosening of laundry in the drum

Centr. = Spin

STOP = end of program

A comparison between the two tables in Fig. 4 shows that, for the same timer steps, the functions performed by the machine in one case and the other (with button A pressed or not pressed) are quite different. In this case, the example program for particularly delicate fabrics (or curtains) consists of a modification of the synthetics program, with the following changes, for example:

- 20 liters of washing water (constant water level II) instead of 8 liters (water level I),

- drum speed during the washing phases 35 instead of 55 min-1, where the binary code received by the electronic module is 5 instead of 1,

- Drum movement during the washing process corresponds to 3 minutes movement/12 minutes standstill instead of 8 minutes movement/7 minutes standstill (Code 5 instead of Code 1),

- Deactivation of all spin cycles (code 12 instead of 8 and 6 instead of 2).

From the above it is immediately apparent how, by pressing button A, it is possible to completely change the functions normally provided for by the basic synthetic washing program without changing the timer cams. Taking into account the fact that the majority of commercially available washing machines are equipped with a temperature selector for the washing liquid temperature, it is obvious that the operator also has options in this respect.

The above description is purely an illustrative example, which does not imply any limitation either as regards the circuit section or as regards the washing procedure for particularly delicate fabrics. Many modifications can be made to the circuit diagram provided as an example. For example, the second section of button A can be inserted at terminal 16 of the ME module instead of at terminal 15, with effect on the most significant bit of the code. In addition, the characteristics of the additional special program can differ from those described above, in order to obtain special programs for other types of laundry or washing processes.

Features and advantages of the washing machine according to the invention have become clear from the above description.

It should be emphasized in particular that by additionally equipping a washing machine provided with an electromechanical timer with a button, a new basic washing program can be developed according to the invention, in particular a program for particularly delicate fabrics or for curtains, without the manufacturing costs increasing significantly.

It should also be emphasized, as the expert will certainly recognize, that the addition of a fourth basic washing program is something completely new and has nothing to do with the so-called reduced programs, i.e. partial programs based on any basic washing program, as mentioned at the beginning of this description.

Fig. 3 shows a simplified block diagram of the functional principle of the machine for a particularly advantageous embodiment of the invention.

In the above figure, the same reference numerals as in Fig. 1 are used to designate technically corresponding elements. In Fig. 3, IC designates a controlled electronic switch, for example a triac, and MT designates the control motor of the timer.

In the case of Fig. 3, the ROM also stores some tables used by the microcontroller MP to set, when button A is pressed, the MT motor switch-on and switch-off times for the timer T during the various phases of the selected washing program.

The aforementioned tables in the ROM memory and the built-in clock enable the microcontroller MP to monitor the IC switch to provide fixed on and off clocks for the timer motor MT, which can be clocked according to the proposed change.

For further details on the timing of the timer motor, reference is made to the Italian patent application T094A000495, filed simultaneously by the same applicant, entitled "Improvements to a washing and/or drying machine".

The operation of the washing machine according to the invention is as follows according to the simplified diagram in Fig. 3:

The operator selects the initial program, i.e. the synthetic program, by operating the electromechanical program switch and the special program for particularly delicate fabrics by pressing button A. The machine can then be switched on using the main switch.

The machine carries out the washing programme for particularly delicate fabrics, as described above with reference to Fig. 1 and 2, but in this case the times set by the programme selector, which are set in a known manner, can also be changed.

Based on the binary codes, modified by pressing button A, transmitted by the timer T to the ME module and the data from the additional tables stored in the ROM, the MP microcontroller is able to set the switch-on and switch-off times for the timer motor MT for one or more different phases of the selected washing program.

If the microcontroller MP detects that another code has arrived (e.g. code 5 according to the table above) when the A button is pressed, it will, for example, use the data from the stored table to power the timer motor MT via the switch IC for 12 seconds and then interrupt the power supply a predefined number of times for 48 seconds.

A practical example can be given using a program switch cam, e.g. the cam that enables a rinse cycle to be carried out, assuming that the profile of the cam is designed in such a way that the electrical contact that enables the motor M to rotate for 3 minutes remains closed while the timer motor MT continues to rotate. In the above case, where button A is pressed, the 3-minute value for the cam can be "extended" according to the data contained in the ROM. According to the invention, we achieve this in practice by clocking the motor MT of the electromechanical program switch so that the cams in question are also moved in pulses as soon as the respective contacts are closed.

In our specific case, the microcontroller MP can supply the timer motor MT via the switch IC for 12 seconds, interrupt the power supply for 48 seconds, resume it for 12 seconds and interrupt it again for 48 seconds, and so on, until the corresponding cam profile is no longer fully detected by the sensor.

This system can of course also be applied to other phases of a clothes washing machine, for example to extend the soaking, bleaching and spinning phases, etc., i.e. the MP microcontroller can change or not change the duration of each phase depending on the modified code received.

It is therefore clear that, using the procedure described above, it is also possible to vary the duration of the individual phases of a washing programme in order to obtain a special programme which is different from the three basic washing programmes originally provided for by the electromechanical timer.

It is also clear to the expert how the system described above can be used in a washing machine where the heating of the washing liquid is time-controlled. (and not through a special thermostat) allows the operating temperature of the machine to be varied. Therefore, in appropriate cases, by pressing button A, the liquid level, liquid temperature and movement of the laundry, ie the chemical action, thermal action and mechanical action on the laundry, can be modified compared to one of the three basic traditional washing programmes.

The invention described above can also be applied in a simple manner to dishwashers when there is a need for an additional gentle program or the possibility of "extending" essential fixed times set by an electromechanical timer by modifying a basic program (for example, for the correct use of the washing pump energy in the case of particularly delicate dishes or for the extension of special cleaning and/or rinsing phases in the case of particularly heavily soiled dishes).

Finally, it is also clear that the washing machine can also be equipped with more than one button of the type marked with A (e.g. several buttons connected in series for changing the program) in order to enable a selection between several special programs.

Claims (12)

1. Multi-program washing machine, containing: - an electromechanical programming device (T, MT, A₁-A₁₂, B₁- B₁₂, C₁-C₁₂, D₁-D₁₂) for selecting a plurality of basic washing programs, - level sensor means (P1, P2) for adjusting the level of liquid to be supplied to the washing machine during the basic washing programs, - an electronic microcontroller (ME, MP) for controlling the operation of a motor (M) provided in the machine during the basic washing programs, wherein the electromechanical programming device (T, MT, A₁-A₁₂, B₁-B₁₂, C₁-C₁₂, D₁-D₁₂) transmits control codes to the microcontroller (ME, MP) and controls the operation of the level sensor means (P1, P2), and - a manually operable control element (A), characterized in that the actuation of the control element (A) modifies both the codes transmitted by the electromechanical programming device (T, MT, A₁-A₁₂, B₁-B₁₂, C₁-C₁₂, D₁-D₁₂) to the electronic microcontroller (ME, MP) and the level of liquid to be supplied to the machine, in order to obtain one or more washing programs that are different from the basic washing programs. 2. Washing machine according to claim 1, characterized in that the codes contain the codes used by the electronic microcontroller (ME, MP) to control the operation of a motor (M) provided in the machine. 3. Washing machine according to claim 1, characterized in that the control element (A) also modifies the drive times of a motor (MT) which is part of the electromechanical programming device (T, MT, A₁-A₁₂, B₁-B₁₂, C₁-C₁₂, D₁-D₁₂), in order to change the times of one or more control phases provided for by the selected washing program. 4. Washing machine according to claim 1, characterized in that the control element comprises a button (A) which, when actuated, modifies the value of at least one bit of the codes transmitted to the microcontroller (ME, MP), the modified bit being in particular the most significant bit. 5. Washing machine according to claim 1, characterized in that the washing machine is a laundry washing machine and that the control element (A), when actuated, carries out an extra-gentle program, in particular a curtain washing program. 6. Washing machine according to claim 5, characterized in that the extra gentle program is derived from a synthetic washing program and in particular contains: - increased water intake, - a reduced washing speed (35 min&supmin;¹), - a shorter drum movement time (20%), - suppression of the spin phase, - engine interruption during certain phases. 7. Washing machine according to claim 3, characterized in that electrical control means (MP, IC) are provided which, when the control element (A) is actuated, are able to pulse the energy of the motor (MT) of the electromechanical programming device (T, MT, A₁-A₁₂, B₁-B₁₂, C₁-C₁₂, D₁-D₁₂), i.e. to alternate energy phases of the motor (MT) with non-energy phases of the motor (MT). 8. Washing machine according to claim 7, characterized in that the electrical control means (MP, IC) contain the microcontroller (MP) with associated clock means (CLOCK), permanent storage means (ME) and an electronic switch (IC), in particular a triac, which is controlled by the microcontroller (MP). 9. Washing machine according to claim 8, characterized in that the storage means (ME) contain information which characterizes the times of the motor (MT) in which the motor (MT) is supplied with energy and in which the motor is out of operation when the control element (A) is actuated. 10. Washing machine according to claim 8 and 9, characterized in that the microcontroller (MP) controls the controlled switch (IC) for the pulse energy of the motor (MT) in dependence on a signal from the control element (A) and on the basis of the aforementioned information. 11. Washing machine according to at least one of the preceding claims, characterized in that the washing machine is a laundry washing machine and in that the control element (A) extends one or more control phases provided by the selected washing program, such as soaking, bleaching or rinsing. 12. Washing machine according to claim 1, characterized in that the washing machine is a dishwasher and that the control element (A) further modifies the operation of a washing pump, for example in the case of particularly delicate dishes and/or extends certain washing and/or rinsing phases, for example in the case of heavily soiled dishes.