[001] The present invention relates to a washer/dryer wherein the damage, which occurs at resonance speed reached during the spinning cycle is minimized.

[002] In washer/dryers, preferably in washing machines, the rotating axis and the center of mass do not overlap if the clothes which cling to the inner wall of the drum during the spinning cycle are not distributed in balance. The dangerous centrifugal forces occurring in this case may result in excessive forcing of the washing machine resistance, creation of harmful vibrations and even the movement of the washing machine.

[003] In state-of-the-art embodiments, in order to overcome this problem during the spinning cycle, the unbalanced load created inside the drum rotating about its center is detected and the spinning cycle algorithm and mostly the speed of the last spinning cycle to be applied is determined according to the detected unbalanced load amount. During these processes, the most important problem encountered about the unbalanced load is the resonance speeds which occur during the transitions between the washing speeds and the spinning speeds. The resonance speed corresponding to the natural vibrational frequency of the entire washer/dryer structure which operates dynamically, should be passed without a problem so that the washer/dryer or its components are not damaged.

[004] The state-of-the-art European Patent document no. EP0565157 describes a method wherein the difference between the maximum and the minimum speeds under constant torque and the amount and the position of unbalanced load are detected and a component, which compensates the effect of the unbalanced load on the average torque required for increasing the speed.

[005] The United States of America Patent no. US4513464 describes the acceleration control with unbalanced load in devices that create a centrifugal force.

[006] The aim of the present invention is to design a washer/dryer which is enabled to pass the resonance speed corresponding to the common natural vibration frequency of the components in a safe and harmless way during the transition from the normal washing speeds to spin cycle speeds.

[007] The washer/dryer designed to fulfill the aim of the present invention is shown in the attached figures, where:

[008] Figure 1 - is the side schematic view of a washer/dryer.

[009] Figure 2 - is front schematic view of a washer/dryer.

[010] Figure 3 - is the time - speed graph showing the operation phases in a washer/dryer.

[011] Figure 4 - is a detail D of Figure 3 of a washer/dryer passing the resonance speed

with constant and decreasing accelerations. [012] Figure 5 - is the speed - time graph obtained by a tachogenerator in a preset number of revolutions of a motor. [013] Figure 6 - is the graph showing the force applied on the drum changing with the position angle of the drum. [014] Elements shown in the figures are numbered as follows:

1. Washer/dryer

2. Drum

3. Control card

4. Attenuator

5. Motor

6. Tub

7. Tachogenerator

8. Body

[015] The washer/dryers, especially the front loading washing machines comprise a body

(8), a control card (3), a drum (2) into which the laundry (L) defined as load are placed, providing washing and spinning by rotating around an axis, a tub (6) into which the drum (2) is situated and moves rotatingly within, a motor (5) which actuates the drum (2), one or more attenuators (4) such as springs or shock-absorbers, which attach the tub (6) to the body (8), supporting the tub (6) and the drum (2), and holding the drum (2) and the tub (6) in place by attenuating the forces occuring during the dynamic rotation movements of the drum (2) inside the tub (6) , and a tachogenerator (7) connected to the motor (5), calculating the speed data of the motor (5) and accordingly the drum (2), determining the wash load amount and the positioning of the load on the drum (2) while in motion with the help of the calculated speed data.

[016] The control card (3) comprises at least one micro processor and at least one internal/external data storage unit. The data storage unit can be an external unit on the control card (3) or can be a RAM, ROM, EEPROM unit within the microprocessor as well. In the preferred embodiment, the data is collected on a ROM included in the microprocessor.

[017] The washer/dryers (1) go through a water discharge phase (110) during which the washing water inside is drained, a distribution phase (120) where the drum (2) is spun clockwise or counterclockwise to tumble the clothes so that the clothes entirely cling to the inner walls of the drum (2) , a prespin phase (130) during which resonance frequencies are quickly passed, reaching a prespin speed greater than the resonance spin speed (wr) with a high acceleration in a short time to avoid the collision of the components to each other or movement of the washer/dryer (1), spinning for a time period while ensuring that the clothes are clung on the inner walls of the drum (2) and

also that enough water is discharged so that water does not cause excessive collisions between the tub (6) and the drum (2), preparing a medium where clothes are firmly clung to the walls of the drum (2) with minimum friction of water-drum-tub and laundry-glass door, and a spinning phase (140) during which the water retained in the laundry (L) is drained off the laundry (L) with the speed and time interval evaluated using the data obtained from the measurements in the previous phases.

[018] During resonance speed (wr) transition (130), the motor force (Fm) applied on the washer/dryer (1) enabling the motor (5) to rotate the drum (2), the weight force (Fg) created as a result of the gravitational acceleration applied to the masses of the drum (2) and the washload inside and the centrifugal force (Fc) created during rotation of the drum (2) should be balanced everywhere on the drum (2). In the embodiment which is the object of the present invention, the gravitational force (Fg) and the centrifugal force (Fc) occuring at a known momentary position of the drum (2), are attenuated with the applied motor forces (Fm). The momentary position of the drum (2) is calculated by the help of the data received from the tachogenerator (7).

[019] During the prespin phase (130), following the actuation of the motor (5), the tachogenerator (7) takes speed measurements continuously. As a result of the rotation of the drum (2), when these momentary speed values measured in the prespin phase join together in a time-speed graph, they form a sinusodial curve (Figure 5) which repeats periodically around an axis. As can be seen from this graph, the vertices corresponding to the highest (X) and the lowest (Y) points of the curve in a period (T), show the measured data of the highest (wl) and the lowest (w2) momentary speeds. These points (X, Y) correspond to the points when the motor (5) is forced rotating the drum (2) (the lowest position of washload in the drum (2) ) or when rotation is easy (the highest position of washload in the drum (2) ) since the washload clings to the drum

(2) wall at especially the prespin (130) and the spin (140) speeds. The highest speed corresponding to the part between the two vertices (X), forms a period (T) for this sinusodial curve, the time duration of a period (T) in correlation with the circumference of the drum (2), when evaluated determines the momentary position of the drum (2) during its motion. In the embodiment of the present invention, these positions are utilized in actuating the drum (2) with different accelarations by the control card

(3) and the motor (5) corresponding to these positions. The additional torque to be applied on the motor (5) during resonance speed (wr) transitions is determined according to the amount of the washload.

[020] In the embodiment which is the object of the present invention, more than one angular positions on the drum (2) are specified. The lowest point in the drum (2) where the washload is collected due to gravity when the drum (2) is not in motion, is taken as a reference point and a period (T) is determined by the other positions according to this

point. This point makes a "0" degree angle with the central axis of the drum (2) (bA =0 °). This point where the speed is the highest after starting to rotate is just opposite the point where the washload is at the highest point, corresponding to the point of lowest speed of the drum (2). The clockwise arc between this point where the speed of the drum (2) is the lowest and the lowest point of the drum (2), is 180 degrees (bU = 180°). The other angular positions are chosen according to the position of the attenuators (4) corresponding to the tub (6).

[021] In the preferred embodiment, four attenuators(4) are utilized and the attenuators (4) are positioned so that one is situated at thirty degrees to the right and left of the lowest point (bA=0°) and the highest point (bU=180°). In this embodiment, the first attenuator (4) is clockwise 30 degrees (bl=30 ) away from the lowest point (bA=0 ), the second attenuator (4) is clockwise 150 degrees (b2=150°) away from the lowest point (bA=0°), the third attenuator (4) is clockwise 210 degrees (b3=210 ) away from the lowest point (bA=0°), and the fourth attenuator (4) is clockwise 330 degrees (b4=330°) away from the lowest point (bA=0 ) (Figure 2).

[022] In the embodiment of the present invention, a control card (3) is utilized which determines the washload position in the drum (2) in motion with a tachogenerator (7), and applies additional torque to the motor (5) in the regions where the attenuators (4) can barely compensate the forces, for fast passage of the drum (2) through these regions during resonance speed transitions according to the determined angular positions of the washload.

[023] The attenuators (4) are positioned just before or after the lowest and highest positions where the washload can be situated in the drum (2). The highest point (X) and the lowest point (Y), and the regions in between the attenuators (4) (0 < b <30), (330 < b < 360) and (150 < b < 210) are passed without accelerating the motor (5), and the regions outside these regions (30 < b < 150) and (210 < b < 330), the motor (5) is a ccelerated. Consequently during the resonance speed (wr) transition (130) of the drum (2), the unwanted forces such as centrifugal forces (Fc) created in the directions that the attenuators (4) can not compensate, are attempted to be attenuated by the applied motor forces (Fm), so that the washer/dryer (1) is affected in the least level possible during the transition.

[024] In this embodiment, motor forces (Fm) should be applied in a magnitude and direction that will create a supporting force balance for the total of centrifugal forces (Fc) and gravitational forces (Fg) that the attenuators (4) cannot compensate so that unwanted forces do not damage the washer/dryer (1). In order to minimize the effects of the generated unwanted forces, at regions, the starting points measured and determined by the tachogenerator (7), the motor (5) is enabled to apply more torque to the drum (2), providing the transition of the drum (2) through these regions without

being affected and not being damaged as a result of the speed (wr). With the embodiment of the present invention, the problems that may arise such as vibration is minimized by enabling fast transition through the resonance regions.