WASHING MACHINE BASKET POSITIONING DEVICE

Abstract: This paper describes a device for positioning the basket of a top-loading washing machine, fitted with a push-button for starting manually the basket rotation, means for stop­ ping the basket automatically in the desired position and a display device to show the basket has been stopped.

Description: The present invention relates to a device for positioning the basket of a top-loading washing machine of the type defined in the preamble of claim 1. A problem with top-loading washing machines is that, after washing or if the machine is stopped during the wash cycle for loading additional items, the basket must be positioned so that the opening is at the top. This can be done manually but is an awkward operation in that the weight is usually unevenly distributed causing the basket to resist rotation. This problem has been partially overcome by means of devices of the above specified kind, such as that disclosed in FR-A-2364286. This prior document discloses a device by which when the wash cycle is over, the user can make the basket rotate slowly by pressing a push switch which controls an electronic speed regulator of the motor which drives the basket. As soon as the user, looking through the port or opening of the machine, sees that the basket has reached the desired position, he releases the push switch and the basket stops. This known device can be dangerous for the user when the operation is carried out with the port open. Further it is quite difficult to obtain accurate positioning of the basket since to achieve this a quite exceptional speed of reaction of the user is required. The problem of bringing the basket a top-loading washing machine to a halt in a predetermined position has been also discussed in DE-U-6603447. The object of the present invention is to provide a device, by which the inconveniences of the prior devices can be overcome. This object is achieved according to the invention by means of a device of the above specified kind, characterised in Claim 1. The invention will now be described in detail with reference to the attached drawing, provided by way of a non-limiting example and showing a partial block diagram of the electric circuit on a washing machine according to the present invention. The letter M in the Figure represents the motor for turning the basket, T a Triac for controlling the speed of the motor and SR a speed control unit which controls the speed of the motor via the said Triac. The said control unit comprises a DC SUPPLY circuit and a Motorola Semiconductors TDA 1085 integrated circuit IC. Further details concerning the integrated circuit IC and its application can be found in the Motorola Preliminary Information N° 3 publication, August 1978, relative to the TDS 1085. The 220V a.c. main voltage is supplied to the two terminals marked ∼ 220V in the Figure. P represents a 2-way push-button switch. When the button is pressed, one way connects one main terminal to the anodes of two diodes D₁, D₂ while the other connects one end of a resistor R₁ to pin 5 of IC. The cathode of diode D₁ is connected both to the supply circuit of unit SR and to Triac T. To the cathode of the other diode D₂ it is connected via a 5.6 Kohm resistor R₂ the parallel of a 10 µF condenser C₁ and a diode Z. The condenser C₁ supplies the electronic circuit of the device and is connected: via a 100 Kohm resistor R₃, to the collector of a phototransistor PT of a H21A1 unit (General Electric photo-electric coupler); via a 1 Kohm resistor R₄, to the collector of a transistor TR₁; directly to the collector of a transistor TR₂. The collector of the phototransistor PT is also connected to a 1 µF condenser C₂ and the base of transistor TR₁. The collector of the same transistor is also connected to the base of the transistor TR₂ and the other end of resistor R. The emitter of the transistor TR₁ is grounded via a first light-emitting diode LD₁. The emitter of transistor TR₂ is grounded via a second light-emitting diode LD₂ (of the H21A1 unit) and a further 1 Kohm resistor R₅ connected in series. The circuit described operates as follows: With the machine off (at the end of the cycle or stopped by the operator), the operator presses button P. Voltage is supplied via diodes D₁, D₂ to IC, the Triac and the automatic electronic positioning circuit. As the 1 µF condenser C₂ is discharged, transistor TR₁ is disabled and its collector voltage high; transistor TR₂ is saturated so that the second light-emitting diode LD₂ is on; the phototransistor PT is saturated with low collector voltage and the 1 µF condenser C₂ remains discharged. Via resistor R₁ current is supplied to pin 5 of IC. This current is such that the motor, together with the basket, starts turning slowly. The basket is fitted mechanically with a cam with a stick-out section which, when the opening of the basket is at the top, intercepts the ray of light between the second light-emitting diode LD₂ and the phototransistor PT. At this stage, the phototransistor PT is disabled and the 1 µF condenser C₂ is charged to about 1.2V. Transistor TR₁ is then saturated and its collector voltage falls. The first light-emitting diode, LD₁, comes on and the motor stops whereas transistor TR₂ is disabled and the second light-emitting diode LD₂ goes off. The circuit remains in this condition until the operator, seeing the light of diode LD₁, releases button P. This cuts off supply to the circuit so that the 100 µF condenser C₁ discharges into transistor TR₁ until the 1 µF condenser C₂ is also discharged. The circuit is now in the initial operating condition. If, however, button P is pressed again (with the basket opening at the top), diode LD₁ comes on immediately and the basket stays still. This is because the stick-out on the cam continues to intercept the ray of light thus disabling the phototransistor. The advantages of the present invention will be clear from the description given. In particular, the operator does not need to see the basket or calculate the exact time to release the push-button when the basket opening reaches the top.

Claims: 1. Device for positioning the basket of a top-loading washing machine, comprising an electronic speed regulator (SR) for controlling the speed of rotation of the eletric motor (M) used to drive the basket, manually operable push-button switch means (P) which, when activated, enables the basket to rotate slowly by providing an appropriate reference voltage to the said electronic speed regulator (SR), characterised in that it further comprises: electric sensor means (LD₂, PT) for producing a stop signal when the basket has reached a desired position, an electronic control circuit (TR₁, TR₂; C₁, C₂; R₃, R₄; LD₁) connected to the electric sensor means (LD₂, PT) and to the said manually operable switch means (P), for stopping the electric motor (M) of the basket in response to said stop signal and for preventing any further activation of the said electric motor (M) before the said manually operable switch means (P) have been deactivated; and in that the device is arranged so as to be operable when the port of the machine is closed. 2. Device according to Claim 1, characterised in that the said electronic control circuit (TR₁, TR₂; C₁, C₂; R₃, R₄; LD₁) is connected to the said sensor means (LD₂, PT), the switch means (P) and the electronic speed regulator (SR) and is capable of assuming a first stable condition in response to the activation of the said switch means (P), for allowing the motor (M) to be stopped, and a second stable condition in response to the said stop signal, in which it prevents any further activation of the said electric motor (M) before the switch means (P) have been deactivated. 3. Device according to Claim 1 or 2, characterised in that said sensor means comprise an electric light-emitting device (LD₂), a device connected to the basket for intercepting the light ray and a photosensitive electric device (PT). 4. A device according to any of the preceding claims, characterised by the fact that it also comprises an optical indicator (LD₁) to be activated when the basket is stopped. 5. Device according any of the preceding claims, characterised in that it comprises a resistor (R₃) connected to an electric capacitor (C₂) so as to form an integrator circuit for introducing a predetermined delay between the said stop signal and the deactivation of the motor (M) which drives the basket. 6. Device according to Claim 4 or 5, characterised in that the power supply to said optical indicator (LD₁) is controlled by the said sensor means (LD₂, PT); the sensor means determining the cut-off of the power supply to the optical indicator (LD₁) when the basket has reached the said predetermined position. 7. Device according to Claim 6, characterised in that said electric light-emitting device is a light-emitting diode (LD₂) and that said photosensitive electric device is a phototransistor (PT) coupled to the light-emitting diode (LD₂). 8. Device according to Claim 6, characterised in that, for controlling the power supply to said optical indicator (LD₁) a transistor (TR₁) is provided which has the control electrode connected to the output of said sensor means (LD₂, PT) for disabling or enabling the power supply to the optical indicator (LD₁) depending upon whether the basket has yet or not yet reached the said predetermined position after the manually operable switch means (P) has been activated.

Inventors: BERTAGNI, QUIRINO, FANCELLI, FABIO, GALEOTTI, MASSIMO
Applicants: MERLONI ELETTRODOMESTICI S.P.A.
Application year: 1980
Main classification: D06F37
IPC codes: H03K17, D06F37