GB1592823A - Machine for washing and spin-drying laundry - Google Patents

Description

(54) A MACHINE FOR WASHING AND SPIN DRYING LAUNDRY (71) We, THOMSON-BRANDT, a French Body Corporate, of 173, Boulevard Haussmann, 75008, Paris, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a machine for washing and spin-drying laundry and more particularly to improvements in or modifications of the machine disclosed in our British Patent Specification No.

1,563,876.

A machine for washing and spin-drying laundry generally has one or more electric motors which for washing drive the laundry drum in rotation at a speed of approximately 50 rpm and for spin-drying cause a predetermined increase in the speed of the drum from 50 rpm to a value equal to or greater than 800 rpm. When the drum is rotating at high speed for spin-drying, if the laundry is incorrectly distributed in the drum this usually gives rise to an imbalance which causes vibration and oscillations which are sometimes severe and often damaging to the machine. When the machine is operating normally, the programme device governs the passage from a low speed of rotation of the drum to a high speed to follow a predetermined pattern.

In this pattern, there is frequently a phase provided in which conditions are brought about which assist in distributing the laundry properly in the drum, such as a certain speed of rotation of the laundry drum, a certain water level in the tank, and so on. It may however happen that the machine is accidentally switched to the high spin-drying speed without passing through the phase which assists in distributing the laundry in the drum, or else there may be an interruption in the spin-drying operation, as a result of a breakdown in the current supply to the machine for example, and the machine may be automatically returned to spin-drying operation when the current supply is restored. When this is the case the laundry, which is either improperly distributed or has become improperly distributed in the drum, produces the disadvantages already mentioned above.

The invention in the main patent application makes it possible to produce an improved machine for washing and spindrying laundry in which, as a safety measure, a direct switch to spin-drying, or its direct resumption after operations have been interrupted, can only take place when it is possible for the laundry to be properly distributed in the laundry drum, that is to say when the water in the tank of the machine is above a predetermined level N, and the rotation of the drum resumes at a speed of substantially 50 rpm and the speed of the drum rises following a predetermined pattern.

A drum washing machine according to the main patent application is operative to wash at a drum speed of substantially 50 rpm and to spin-dry with the drum rotating at speeds ranging from substantially 50 rpm to a value equal to or greater than 800 rpm, said machine including a DC motor for driving said drum and a control system, said control system comprising a programme device having at least four electrical contacts, an assembly for controlling the speed of said DC motor, and a pressure switch sensitive to high and low levels of water in the tank of the machine and having two electrical contacts connected to said programme device and to a bistable electronic flip-flop, the flip-flop having an output connected to said speed controlling assembly so as to control operation of said assembly such that spin-drying cannot be carried out or initiated with either too little or too much water in said tank.

The machine described in the parent specification is able to perform a spindrying operation with the rise in speed progressing as follows: in a phase I there would be a rapid rise in the speed V of the laundry drum from a speed Vl of substantially 50 rpm to a speed V2 of substantially 80 rpm, followed by a slow rise from V2 to a speed V3 of substantially 160 rpm and a fast rise from V3 to a speed V4 of substantially 450 rpm, in which phase a pump drains the tank of the machine; in a phase II the speed V of the drum remains relatively constant at V4; in a phase III the speed V of the drum rises and then remains at a speed Vr of substantially 800 rpm, and in a phase IV there is a rapid drop in the speed of the drum for V5 to zero.

In phase I of the spin-drying operation, if the drain pump of the machine is blocked, thus making it impossible to remove the water from the tank, the spin-drying continues to a point towards the end of phase I where the programme device, which is pursuing its normal sequence of operations, opens certain of its contacts and indirectly causes the spin-drying operation to come to a halt. This ensures that the machine is safe in operation but in this interval of time the speed of the drum has nevertheless come close to the speed V4 of the order of 450 rpm in a tank which still contains water. The water which is carried round with the drum could form a vortex and in colliding with the joint for the access door could give rise to unpleasant noise and slight leakage to the exterior.

The present invention has as an object the avoidance of these disadvantages.

Accordingly the present invention consists in a drum washing machine as claimed in claim I of British Patent Specification No. 1,563,876 and further comprising three logic circuits which receive inputs from the contacts of said programme device and of said pressure switch, and from the output of said flip-flop, one of said logic circuits having its output connected to the input of a speed increase generating circuit which forms part of said speed controlling assembly, and the outputs of the other two logic circuits being connected to different inputs of a device in said speed controlling assembly having a plurality of inputs which correspond to the different speeds of the drum of the washing machine, another of the inputs of said device being connected to the output of said speed-increase generating circuit. In particular, in cases where the drain pump is blocked, the speed of the drum is held at a predetermined level which is usually less than that which would result in water being flung against the joint for the access door.

In order that the invention may be better understood, an embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. I is a schematic perspective view of a machine according to the invention for washing and spin-drying laundry, Fig. 2 is a partial schematic view of the electrical circuit of a system for controlling the drive motor of the washing and/or spindrying machine shown in Fig. 1, Fig. 3 is a curve, plotted as a function of time, for the spin-drying speeds of the laundry drum of the laundry washing and spin-drying machine of Fig. I, the curve being divided into phases I, II, III and IV, and Fig. 4 is a diagram of the periods during which the contacts of the control system of Fig. 2 are closed, which diagram is divided into phases I, II, III and IV corresponding t'o the four phases shown in Fig. 3 of the curve for spin-drying speed.

An embodiment of-a washing and spindrying machine I according to the invention is illustrated in Fig. 1. The machine has a cabinet 2, a tank 3, a laundry drum 4, an electric DC drive motor 5 and an improved system 6 for controlling this motor 5, which system automatically causes the machine I to wash at an ordinary drum speed V of substantially 50 rpm, and to spin-dry following the pattern indicated by the curve of Fig. 3 in which: in a phase I there is a rapid increase in the speed V of the laundry drum from a speed V1 to a speed V2 of substantially 80 rpm for example, followed by speed V2 being held constant and then by a slow rise from V2 to a speed V3 of approximately 160 rpm for example and by a fast rise from V3 to a speed V4 of substantially 450 rpm for example, during which phase a pump (not shown) drains the tank; in a phase II the speed of the drum is held relatively constant at V4; in a phase III there is a rapid rise in the speed of the drum from V4 to a speed V5 of substantially 800 rpm for example, followed by a dwell at a relatively constant speed of V5; in a phase IV there is a rapid drop in the speed of the drum from V5 to a value of zero.

The system 6 for controlling the electric DC motor 5 (Fig. 2) comprises, in combination, as in the main patent application, firstly, a programme device 7 which has at least four contacts 8, 9, 10, II, secondly a pressure switch 14 having two contacts 15, 16, thirdly an electronic flipflop 12, and fourthly an assembly 13 for controlling the speed of operation of the motor 5. The contacts of the pressure switch 14 are sensitive to the level of water in the tank of the machine. The "low level" contact 15 and the "high level" contact 16 respectively close when the level of water in the tank 3 is below a predetermined level NI and above a predetermined level N2. In the control system 6, the first and second contacts 9 and 10 of the programme device 7 are respectively connected in series with the low and high level contacts 15 and 16 of the pressure switch 14 whilst the third contact 8 of the programme device 7 is connected in parallel with the pair of series contacts 9 and 15. The flip-flop or changeover device 12 is a logic circuit having a known bistable system which has a first input T, a second input S, a first output 9 and a second, complementary output Q.

The first input T of the flip-flop 12 is connected to the common point 17 of parallel contacts 8, 9 and 15, and input S is connected to point 18 of the series contacts 10 and 16 of programme device 7 and pressure switch 14. The assembly 13 for controlling the speed of the motor 5 is of a known type which comprises chiefly a system 19 termed a speed-increase rampgenerator and a device having a plurality of inputs, for example four inputs E1, E2, E3 and E4 which correspond to the four speeds V of the laundry drum which are of substantially 50 rpm, 80 rpm, 450 rpm and 800 rpm respectively.

The system 19 is a "resistancecapacitance" system which causes the speed of the motor 5 to change to bring about a change in the speed of rotation V of the drum from approximately 80 rpm to 450 rpm following a pre-established pattern of rise as indicated in Fig. 3.

Input E, is connected directly to point 17.

When voltage is present at point 17, the motor 5 turns at least at a speed which corresponds to a drum speed V1 of substantially 50 rpm. Input E2 is connected to a logic circuit 21 having two inputs of which one is connected to point 17 and the other to point 18. When point 17 and 18 both have voltage present at them, the motor 5 turns at least as a speed which corresponds to a drum speed V2 of substantially 80 rpm. Input E2 is connected, via system 19, to a logic circuit 22 having three inputs of which the first is connected to point 17, the second to point 18 and the third to the first output Q of flip-flop 12, the second, complementary output Q of the latter not being used. When voltage is present at point 17, the Q output is in the working state and there is no voltage at point 18. The motor 5, under the control of system 19, increases its speed, and thus the speed of the drum from V2 to V4 for example.

If on the other hand voltage is present at both of points 17 and 18 and output Q is in the working state, there is still a supply to the motor 5 via input E2 of the control assembly 13 and the motor turns at a speed corresponding to a drum speed V2. Input E4 is connected to a logic circuit 23 having three inputs of which the first is connected to point 17, the second to the first output Q of change-over device 12 and the third to a point 20 on contact 11 of the programme device 7. When voltage is present at both of the points 17 and 20 and the first output Q of change-over device 12 is in the working state, the motor 5 turns at a speed which corresponds to a speed V5. If one of these conditions changes, there is no longer a supply to motor 5 via input E4 and its speed alters.

During the four phases of spin-drying (Fig. 3), the pump (not shown) for draining water from the machine operates continuously. In addition, the control system 6 has a programme for the closing of the four contacts of the programme device 7 and the two contacts of the pressure switch 14, as indicated in the diagram of Fig. 4 in which the numerals indicate the contacts and the heavy lines indicate the periods for which they are closed. The diagram is divided into four phases I, II, III, IV corresponding to those of the spin-drying curve of Fig. 3. Contacts 8 and 10 are thus closed during phase I of the spin-drying operation, whilst contact 9 is closed during phases I, II and III and contact 11 is closed during phase III. The water is drained from the tank of the machine during phase I of the spin-drying operation. Contact 16 of the pressure switch 14, i.e. the high level contact, closes when the water in the tank is above a predetermined level N2 and opens when the water falls below this level N2. In practice, contact 16 opens before the end of phase I of the spin-drying operation. On the other hand, contact 15 of the pressure switch 14, i.e. the low level contact, is open when the water in the tank of the machine is above the said predetermined level N1 and closes when it is below this level N,. In practice contact 15 closes before the end of phase I of the spin-drying operation.

The electrical interconnection, described in a previous paragraph, between the inputs of the speed control assembly 13 and the programme device 7, pressure switch 14 and change-over device 12 not only allows spindrying to take place following a given curve for drum speed but also provides great safety in the operation of the machine.

In the embodiment illustrated, this electrical interconnection (Fig. 2), supplemented by a programme for opening and closing the contacts shown in the diagram of Fig. 4, enables spin-drying to take place following the curve for drum speed shown in Fig. 3 and allows the machine to be made very safe in operation, as will be explained in detail below.

The flip-flop 12 of the control system 6 is a logic circuit having a known bistable system which, to change from one predetermined state (called the rest state) to the other (termed the working state) requires a pulse to be applied to a predetermined input. Once this first changeover has taken place, to cause the flip-flop to change back from the working state to the rest state a pulse has to be applied to another input. When the first input S of the flip-flop is at the "0" level, that is to say it is unsupplied or switched off, its first output Q is always at the "0" level, i.e. in the rest state, whatever the state of supply to its second input T, i.e. no matter whether T is supplied or not, or in other words whether it is at the "1" level or the "0" level. When the second input T is at the "1" level for example and the first input S changes from the "0" level to the "1" level, the first output Q of the flip-flop changes over from the "0" level to the "1" level, that is to say from the rest state to the working state. If input T remains at the "1" level and input S returns to "0", the first output Q remains at the "1" level. In the event that input T now changes to the "0" level, the first output Q reverts to the "0" level, i.e. the rest state, input S having remained at its "0" level.

During normal operation of the machine 1, spin-drying begins at the moment indicated by the curve and diagram shown respectively in Figs. 3 and 4, when contacts 8, 9 10 and 16 are closed (Fig. 2) and contacts 15 and 11 are open. Since contacts 10, 16 and 8 are closed, inputs S and T of flip-flop 12 are at the "1" level and the first output Q of the flip-flop is at the "1" level.

Contact 8 and output Q act simultaneously on the assembly 13 for controlling the speed of motor 5. The laundry drum 4 turns for example at a speed V1 of approximately 50 rpm and changes rapidly to a speed V of approximately 80 rpm. Since there is no supply to input E2 of the control assembly 13, the drum 4 continues to turn at V2.

During this time the drain pump is removing water from the tank. When the water drops below the above-mentioned level N1, contact 16 of the pressure switch 14 opens and its contact 15 closes. Input S of flip-flop 12 then goes to the "0" level, whilst input T, being supplied through the three contacts 8, 9 and 15, remains at the "1" level, i.e. in the working state. Input E3 of the speed controlling assembly 13 thus has a supply. The speed of the drum increases in a pre-established pattern under the control of the system 19 and, having reached V4 (450 rpm) for example, is held relatively constant at this value, input E4 of the control assembly 13 not having a supply. The end of phase I is marked by contacts 8 and 10 opening. The closure of contacts 9 and 15 continues into phase 11, which causes the speed of the drum to remain unchanged at V4 (450 rpm). Phase III begins with contact 11 closing. Since input E4 of the assembly 13 now has a supply, the speed of the drum changes rapidly from V4 (450 rpm) to V5 (800 rpm) and remains relatively steady at this level during phase Ill of the spin-drying operation. Phase III of spin-drying concludes with the opening of contacts 9 and 11. Input T of flip-flop 12 returns to the "0" level and output Q of the flip-flop then goes to the "0" level or rest state. In phase IV, since none of its inputs are supplied, assembly 13 allows the speed of the motor 5 to drop to zero and the spin-drying operation comes to an end.

Since the tank 3 of the machine I is empty, contact 16 of the pressure switch 14 is open and because of this input S of flipflop 12 is at the "0" level. Whatever the logic level at input T of flip-flop 12, or in other words whatever the state, open or closed, of contacts 8, 9 and 11 of the programme device 7, the first outlet Q of flip-flop 12 will always be at the "0" level, i.e. will remain in the rest state. The laundry drum is able to turn at V1 (50 rpm) when contact 8 closes but spin-drying cannot be initiated. The improved control system 6 of the machine will thus not permit spindrying to begin when the tank 3 of the machine 1 is empty of water. There is thus no risk of inbalance in the laundry drum due to the laundry being improperly distributed, which would cause mechanical damage to the machine during spin-drying.

In phase I of the spin-drying operation, when the water in the tank of the machine is above the level N2 the contact 16, mentioned in a previous paragraph, is closed, if there is a breakdown in the current supply at this moment, the spindrying is necessarily interrupted. However, when the current is restored, since contacts 8, 10 and 16 are closed the laundry drum turns at V1 (50 rpm) and rapidly reaches a speed V2 (80 rpm) and its speed then follows the upward course indicated (Fig. 3) in the normal way. Because of this the spin-drying operation starts again from the beginning with the laundry properly distributed in the drum, given that the water remaining in the tank of the machine, whose level is above the predetermined level N2, is sufficient to allow the laundry to slide easily when the drum rotates and thus to prevent any imbalance from being created.

In the event of a current breakdown occurring when the water still in the tank is below the above level N2, when current is restored the laundry drum is able to turn at V1 (50 rpm) but spin-drying cannot begin.

This case is similar to that of beginning spindrying with the tank of the machine empty of water, as described in a previous paragraph. Output Q of flip-flop 12 remains in the rest state given that there is no supply to its input S because contact 16 of the pressure switch 14 is open. The improved machine-control system 6 thus makes it possible to avoid spin-drying taking place with the laundry improperly distributed as a result of there being an insufficient quantity of water in the tank.

If on the other hand the pump for draining the machine is blocked, and the water cannot be removed from the tank, since contact 16 remains closed spin-drying only takes place at V2 (80 rpm) in phase I, there being no supply to input E3 of assembly 13. However, as soon as contacts 8 and 10 of the programme device 7 open at the beginning of phase II, since contact 15 of the pressure switch 14 is open the spindrying operation stops. Because of this safe operation by the machine is ensured.

Should the programme device 7 accidentally be set directly to the position which corresponds to that which it occupies in phase II or phase III of the spin-drying operation, whatever the amount of water present in the tank of the machine, the drum would be able to turn at V1 (50 rpm) but spin-drying cannot begin in view of the fact that contacts 8 and 10 of the programme device 7 are open in the said phases and there is no supply to input E2 of assembly 13. In addition, when input S of flip-flop 12 is at the "0" level, i.e. is unsupplied, its first output Q is also in the rest state whatever the state of supply at input T of flip-flop 12 and there is no supply to inputs E2 and E4.

Any danger of the laundry drum turning at high speed (450 or 800 rpm) without the laundry in it having first been properly distributed is thus avoided.

WHAT WE CLAIM IS: 1. A drum washing machine as claimed in claim I of British Patent Specification No.

1,563,876 and further comprising three logic circuits which receive inputs from the contacts of said programme device and of said pressure switch, and from the output of said flip-flop, one of said logic circuits having its output connected to the input of a speed increase generating circuit which forms part of said speed controlling assembly, and the outputs of the other two logic circuits being connected to different inputs of a device in said speed controlling assembly having a plurality of inputs which correspond to the different speeds of the drum of the washing machine, another of the inputs of said device being connected to the output of said speed-increase generating circuit.

2. A machine as claimed in claim 1, wherein first and second contacts of the programme device are respectively connected in series with the two contacts of the pressure switch and connected to the two inputs of the electronic flip-flop, and wherein a third contact of the programme device is connected in parallel with the series connected pair of contacts formed by the first contact of the programme device and the associated contact of the pressure switch.

3. A machine as claimed in claim 2, wherein the device in said speed controlling assembly has four inputs, and wherein the junction point between the series connection of the first contact of the programme device to the contact of the pressure switch and the third contact of the programme device is connected to a first input of said device in said speed controlling assembly.

4. A machine as claimed in claim 3, wherein said junction point is connected to an input of each of said three logic circuits.

5. A machine as claimed in claim 4, wherein said junction point is connected to one input of said flip-flop, and the series connection of said second contact of the programme device and the other contact of said pressure switch is connected to the other input of said flip-flop.

6. A machine as claimed in claim 5, wherein said junction point is connected to a first of four inputs of said device in said speed controlling assembly, wherein a first of said logic circuits has an input connected to said series connection of the second contact of the programme device and said other contact of said pressure switch and an output connected to a second input of said device in said speed controlling assembly, wherein a second of said logic circuits has its output connected to said speed increase generating circuit, has an input connected to an output of said flip-flop, and a third input connected via an inverter to the series connection of said second contact of the programme device and said other contact of the pressure switch, and wherein the third of said logic circuits has its output connected to the fourth input of said device in the speed controlling assembly, said third logic circuit having one input connected to the same output of the flipflop as the second logic circuit, and a third

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. pressure switch 14 is open. The improved machine-control system 6 thus makes it possible to avoid spin-drying taking place with the laundry improperly distributed as a result of there being an insufficient quantity of water in the tank. If on the other hand the pump for draining the machine is blocked, and the water cannot be removed from the tank, since contact 16 remains closed spin-drying only takes place at V2 (80 rpm) in phase I, there being no supply to input E3 of assembly 13. However, as soon as contacts 8 and 10 of the programme device 7 open at the beginning of phase II, since contact 15 of the pressure switch 14 is open the spindrying operation stops. Because of this safe operation by the machine is ensured. Should the programme device 7 accidentally be set directly to the position which corresponds to that which it occupies in phase II or phase III of the spin-drying operation, whatever the amount of water present in the tank of the machine, the drum would be able to turn at V1 (50 rpm) but spin-drying cannot begin in view of the fact that contacts 8 and 10 of the programme device 7 are open in the said phases and there is no supply to input E2 of assembly 13. In addition, when input S of flip-flop 12 is at the "0" level, i.e. is unsupplied, its first output Q is also in the rest state whatever the state of supply at input T of flip-flop 12 and there is no supply to inputs E2 and E4. Any danger of the laundry drum turning at high speed (450 or 800 rpm) without the laundry in it having first been properly distributed is thus avoided. WHAT WE CLAIM IS: 1. A drum washing machine as claimed in claim I of British Patent Specification No.

1,563,876 and further comprising three logic circuits which receive inputs from the contacts of said programme device and of said pressure switch, and from the output of said flip-flop, one of said logic circuits having its output connected to the input of a speed increase generating circuit which forms part of said speed controlling assembly, and the outputs of the other two logic circuits being connected to different inputs of a device in said speed controlling assembly having a plurality of inputs which correspond to the different speeds of the drum of the washing machine, another of the inputs of said device being connected to the output of said speed-increase generating circuit.

2. A machine as claimed in claim 1, wherein first and second contacts of the programme device are respectively connected in series with the two contacts of the pressure switch and connected to the two inputs of the electronic flip-flop, and wherein a third contact of the programme device is connected in parallel with the series connected pair of contacts formed by the first contact of the programme device and the associated contact of the pressure switch.

3. A machine as claimed in claim 2, wherein the device in said speed controlling assembly has four inputs, and wherein the junction point between the series connection of the first contact of the programme device to the contact of the pressure switch and the third contact of the programme device is connected to a first input of said device in said speed controlling assembly.

4. A machine as claimed in claim 3, wherein said junction point is connected to an input of each of said three logic circuits.

5. A machine as claimed in claim 4, wherein said junction point is connected to one input of said flip-flop, and the series connection of said second contact of the programme device and the other contact of said pressure switch is connected to the other input of said flip-flop.

6. A machine as claimed in claim 5, wherein said junction point is connected to a first of four inputs of said device in said speed controlling assembly, wherein a first of said logic circuits has an input connected to said series connection of the second contact of the programme device and said other contact of said pressure switch and an output connected to a second input of said device in said speed controlling assembly, wherein a second of said logic circuits has its output connected to said speed increase generating circuit, has an input connected to an output of said flip-flop, and a third input connected via an inverter to the series connection of said second contact of the programme device and said other contact of the pressure switch, and wherein the third of said logic circuits has its output connected to the fourth input of said device in the speed controlling assembly, said third logic circuit having one input connected to the same output of the flipflop as the second logic circuit, and a third

input connected to the fourth contact of said programme device.

7. A drum washing machine substantially as hereinbefore described with reference to the accompanying drawings.