Description A WASHER/ DRYER

[0001] The present invention relates to a washer/dryer wherein the breakage of the belt is determined during the washing/drying process.

[0002] In washers/dryers, the drum is generally actuated with a belt driven by a motor, the belt that rotates the drum can break due to high temperature, humidity and heavy operating conditions. The belt berakage that can happen during operation, if not detected in time, leads to blowing of hot air over the laundry in the motionless dram and results in damage of the laundry. In state of the art, various methods are employed for detecting the breakage of the belt.

[0003] In the US3890720 patent, in a clothes dryer, a drive belt rotating the drum is entrained about an idler pulley and the idler pulley is connected to the base with a resilient spring bracket. The spring bracket presses on a switch when the spring tension is relieved upon release of belt tension due to belt breakage or the like and the switch opens the circuit of the motor rotating the drum, thereby cutting off the current.

[0004] In the US5852881 patent, the inventive clothes dryer is provided with a system for preventing the overheating of the clothes in the drum caused by the abnormality in the V-belt, such as the break or derailment thereof. By the system, the power supply to the motor is halted temporarily while the motor is rotated at a predetermined speed, whereafter the motor keeps rotating due to its inertia. During the inertial rotation of a predetermined period of time, the number of rotations of the motor is counted. When the V-belt is in the normal state, the motor is loaded appropriately, so that the speed of the motor fills rapidly during the inertial rotation, and the number of rotations is accordingly small. When, on the other hand, the V-belt is in an abnormal state, the number of rotations is large. Therefore, the state of the V-belt is checked by comparing the number of rotations to a predetermined value, and when the number is smaller than the predetermined value, the drying operation is stopped.

[0005] In the European patent document no. EP 1521880, in a tumbler, a rupture and/or a length change of a belt, especially a drive belt for an electric motor, is detected by a sensor comprising a movable transmission element that is functionally linked with the belt.

[0006] The aim of the present invention is the realization of a washer/dryer wherein the breakage of the belt during the washing/drying process is detected accurately and in a timely manner.

[0007] The washer/dryer realized in order to attain the aim of the present invention is explicated in the claims.

[0008] In the washer/dryer, the laundry is empkced in a drum rotated with a belt that is driven by a motor and the drying air activated by a fan and heated by a heater is passed over the laundry. The belt is produced of an electrically conductive material. The belt is prefer bly produced of carbon or steel wire reinforced material featuring electrical conductivity. Electric current is passed through the belt by means of a power source generating AC or DC electric current and the differences in the electrical parameters (voltage, current, impedance etc. ) of the created closed circuit are measured by a measuring unit to detect whether or not there is a continuous flow of current through the belt. When it is detected that current does not flow through the belt, the control unit is warned and the control unit immediately stops the operation of the heater and the motor.

[0009] The washer/dryer realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

[0010] Rgure 1 - is the schematic view of a washer/dryer.

[0011] Rgure 2 - is the schematic view of a washer/dryer in another embodiment of the present invention.

[0012] The elements illustrated in the figures are numbered as follows:

1. Washer/dryer

2. Drum

3. Motor

4. Belt

5. Fan

6. Heater

7. Power source

8. Measuring unit

9. Control unit

10. Brush

11. , 111. Insulating band

12. Guide

13. , 113. Conductive band

14. , 114. Electrode

[0013] The washer/dryer (1) comprises a drum (2) wherein laundry to be dried is empkced, a motor (3) that activates the drum (2) providing rotation, a belt (4)

produced of an electrically conductive material, e.g. carbon reinforced rubber, providing to transfer the motor (3) drive to the drum (2) a fen (5) maintaining the circulation of the air in the drying cycle and a heater (6) that heats the air of the drying cycle.

[0014] The washer/dryer (1) of the present invention comprises a power source (7) that produces AC or DC current and provides to pass electric current through the electrically conductive belt (4) a measuring unit (8) providing to measure the electrical parameters (voltage, current, impedance etc.) in the closed circuit formed by the belt (4) and the power source (7) and a control unit (9) that detects the belt (4) breakage according to the variations in the electrical parameters measured by the measuring unit (8) and when the belt (4) breakage is detected, warning the user and stopping the operation of the heater (6) and the motor (3).

[0015] In the washer/dryer (1) the current produced in the power source (7) is transferred to the belt (4) on the drum (2) by means of conductive elements. The current that flows through the belt (4) is transmitted to the motor (3) idler pulley made of conductive material, and from the motor (3) idler pulley to the motor (3) and to the measuring unit (8). As long as the belt (4) is not broken, the resistance value effectuated by the belt (4) is measured in the measuring unit (8). At the moment the belt (4) bre&s, since current will not flow through the belt (4) the resistance value read in the measuring unit rises suddenly, and the control unit (9) determines that the belt (4) is broken.

[0016] In an embodiment of the present invention, the washer/dryer (1) comprises a brush (10) made of thin copper or steel conductive wires and positioned on the belt (4) such that the conductive wires directly contact the belt (4) providing to transfer the current produced in the power source (7) to the belt (4) an insulating band (11) wrapped on the outer surface of the drum (4) providing insulation between the belt (4) and the drum (2) and one or more guides (12) on each side of the belt (4) wrapped all around on the outer surface of the drum (4) made of insulative material, preferably produced in one piece with the insulating band (11) providing the belt (4) from being dislocated and also the wires of the brush (10) to fully contact on the belt (4) without projecting from the sides (Rgure 1).

[0017] In this embodiment, the current produced in the power source (7) is transferred to the brush (10) by means of cdbles and to the belt (4) directly from the brush (10). As long as the belt (4) is not broken, the current that flows through the belt (4) flows from the motor (3) idler pulley to the motor (3) and to the measuring unit (8) from there. The resistance of the belt (4) is measured in the measuring unit (8). At the moment

when the belt (4) breaks, since current will not flow through the belt (4) the resistance value read in the measuring unit (8) suddenly rises and the control unit (9) concludes that the belt (4) is broken.

[0018] In another embodiment of the present invention, the washer/dryer (1) comprises a brush (10) that is positioned at a place separate from the belt (4) such that it will contact the drum (2) providing the current produced in the power source (7) to be first directed into the drum (2) to be passed through the humid region in the drum (2) and to be transferred to the belt (4) from inside the drum (2) and a measuring unit (8) that detects the degreee of dryness as well as the breakage of the belt (4) according to the measured parameters (Rgure 2).

[0019] In this embodiment, the washer/dryer (1) comprises an insulating band (111) wrapped around the drum (4) and positioned at a different place than the belt (4) a conductive band (13) wrapped over the insulating band (111) to which the brush (10) contacts, one or more electrodes (14) in connection with the conductive band (13) providing the current to be transferred to the inside of the drum (2) a second conductive band (113) to which the belt (4) contacts and wrapped around the insulating band (11) between the belt (4) and the insulating band (11) and one or more electrodes (114) in connection with the second conductive band (113) providing the current passing through the inside of the drum (2) to be transferred to the belt (4).

[0020] In this embodiment, the current produced in the power source (7) is transferred to the brush (10) by means of cables and from the brush (10) to the inside of the drum (2) by means of the conductive band (13) and the electrode (14). The electric current that crosses the inside of the drum (2) is transferred to the conductive band (113) under the belt (4) and to the belt (4) by means of the other electrode (114). As long as the belt (4) is not broken, the current passing through the belt (4) flows from the motor (3) idler pulley to the motor (3) and from there on flows to the measuring unit (8). In the measuring unit (8) the resistance which is a total of the humid inside of the drum (2) and the belt (4) resistance is measured and the degree of dryness of the laundry in the drum (2) is determined. At the moment when the belt (4) breaks since again current will not flow through the belt (4) the measured resistance value rises suddenly and the control unit (9) concludes that the belt (4) is broken.

[0021] In the washer/dryer (1) of the present invention, the belt (4) breakage that is encountered quite so often due to heavy operating conditions, is immediately determined by a simple and effective method, the operation of the heater (6) and the motor (3) is stopped by the control unit (9) and the user is warned, consequently the blowing of hot

air on the stationary laundry in the drum (2) that cannot rotate due to the belt (4) bredcage is immediately halted, preventing discolorations and damage of the laundry.