EP0477926A1

EP0477926A1 - Washing machine with servo actuator means

Info

Publication number: EP0477926A1
Application number: EP91116373A
Authority: EP
Inventors: Piero Durazzani; Mario Tabasso; Giambattista Dottor
Original assignee: Zanussi Elettrodomestici SpA
Current assignee: Electrolux Zanussi Elettrodomestici SpA
Priority date: 1990-09-27
Filing date: 1991-09-25
Publication date: 1992-04-01
Also published as: IT9045756A1; IT9045756A0; IT1242798B

Abstract

A washing machine, particularly for domestic use, and preferably connected to the water supply mains, said machine comprising at least one of the following operating components: a window or door (3) for charging the articles to be washed into the washing tub, a drawer (3b) for containing the substances used for the washing operation, and/or at least one fixed leg (3c) for supporting the machine on the floor, in which at least one of these components is operable by means of a hydraulic, electric or pneumatic actuator. A hydraulic servo actuator (8) used for this purpose comprises at least one piston (9) actuated by the pressure of the water supply mains transmitted thereto through an arrangement of solenoid valves (5,5A) operable to control the displacement of the piston in opposite directions corresponding to the operations to be carried out in opposite directions.

Description

The invention relates to auxiliary actuator means for operating certain components incorporated in domestic washing machines, particularly laundry washers and dishwashers.
For the correct use of machines of this type, the user has to carry out a number of specific operations. The user of for instance a laundry washer has to pull out a drawer provided with several compartments for containing the various substances to be employed in the course of the washing cycle, and to provide access to the laundering tub by opening the front window or door in the case of a front-charging machine.
The use of a dishwasher, on the other hand, requires the user to open the front door flap and to carefully lower it to its lower end position just above the floor.
These operations, particularly the two last- named ones, require the user to bend down to a very low height and to thus perform an exercise which may be rather irksome to the aged or handicapped persons.
In addition, for cleaning the floor in the immediate vicinity or underneath the respective appliance, the latter has to be moved, if only over a small distance, to another position.
For facilitating this displacement, electric appliances of this type may be provided with a pair of casters, usually at the rear, and in addition with fixed legs for insuring their immobilization in operation.
The displacement of these electric appliances thus requires them to be tilted so as to lift the fixed legs off the floor and to thus permit the machine to be moved with its full weight substantially supported by the casters.
This operation is also rather troublesome and onerous for certain users.
When on top of all this appliances of the type under discussion ar installed within specific pieces of furniture, as in the case of so-called installation- type appliances, these operations become even more fastidious and require nearly always the help of a second person.
It would therefore be desirable, and is in fact an object of the present invention, to provide domestic appliances with quick-acting and safely operable, low-cost and compact servo actuators for performing the described operations to thereby eliminate the shortcomings discussed above.
This object is attained according to the invention by providing appliances of the type defined above with hydraulic, electromechanic and/or pneumatic servo actuators as set forth in the claims of the present application.
The characteristics of the invention will become more clearly evident from the following description, given by way of example with reference to the accompanying drawings, wherein:

fig. 1 shows an automatic actuator for opening and closing the charging window or door of a laundry washer of the front loading type according to an embodiment of the present invention,
fig. 2 shows an automatic actuator for opening and closing a drawer provided with compartments for containing the products used for the laundering operation, according to another embodiment of the invention,
fig. 3 shows an automatic actuator for tilting or lifting a laundry washer according to still another embodiment of the invention,
fig. 4 shows in diagrammatic representation details of a solenoid valve and a hydraulic actuator according to an embodiment of the invention,
fig. 5 shows an electro-mechanical actuator for opening and closing the charging window of a laundry washer in a modified embodiment of the invention,
fig. 6 shows the actuator of fig. 5 as viewed in a direction perpendicular to the view of fig. 5, and
fig. 7 shows an electro-mechanic actuator for tilting or lifting an appliance in a still further modified embodiment of the invention.

With reference to fig. 1 in combination with fig. 4, there is shown a diagrammatic top plan view of a laundry washer of the front-loading type. Illustrated in fig. 1 are a tub 1, a bellows 2, a charging window 3 depicted in two opening stages, a water pipe 4 directly connected to the water supply mains and thus containing water at the mains pressure, a solenoid valve 5 having particular characteristics to be explained as the description proceeds, electric conductors 6 connected to the solenoid valve, another water pipe 7 connecting solenoid valve 5 to a hydraulic actuator 8 comprising a cavity for the displacement of a piston 9 sealingly guided therein, a transmission link 10 connecting piston 9 to window 3, a return spring 11 connecting transmission link 10 to a fixed part of the laundry washer, a further water pipe 12 connecting hydraulic actuator 8 to a second section 5A of solenoid valve 5, and a conduit 13 connecting sections 5 and 5A of the solenoid valve to a discharge component, for instance a discharge filter 14 of the appliance.
A laundry washer of the construction described operates as follows: when the user wants to open the charging window, all he has to do is to activate the normally closed solenoid valve 5, for instance by actuating a push-button switch (not shown) to which conductors 6 are connected. This causes valve element 23 to open, and at the same time valve element 24 to close, to thereby admit water at the mains pressure to pipe 7, and thus to a first pressure chamber 21 of actuator 8 defined by one end face of piston 9 (fig. 4).
The mains pressure thus acting on piston 9 causes it to be extended, resulting in rotation of transmission link 10 to thereby open window 3.
For closing the charging window, the user operates a second element (for instance a closing switch, not shown) to thereby cancel the opening command.
The cancellation of the opening command causes valve element 23 to close, and at the same time valve element 24 to open, resulting in a rapid pressure drop in chamber 21 of actuator 8.
The actuation of the second operating element causes valve elements 25 and 26 of section 5A of the solenoid valve to open and to close, respectively, as a result of which water at the mains pressure is admitted to pipe 12 and thus to a second pressure chamber 27 of actuator 8 disposed on the opposite side of piston 9 with respect to first pressure chamber 21.
In response to the pressure now acting on its other end face, piston 9 returns to its original position adjacent first pressure chamber 21, resulting in transmission link 10 being rotated in the opposite direction to close window 3.
At the same time, the opening of valve element 24 permits the water contained in actuator 8 on the opposite side of piston 9 to be expelled there from through non-pressurized pipe 13 towards a discharge component, for instance discharge filter- pump assembly 14.
The actuator functions in a similar manner as described above during the window opening operation, when valve element 25 is closed and valve element 26 opened for permitting the water contained in pressure chamber 27 to be discharged.
To the skilled artisan it will be evident that the operation of the device can be simplified and rendered more reliable by the employ of valve elements 23, 24, 25 and 26 of the normally open and normally closed type, respectively. With reference to the drawings, valve elements 23 and 26 may thus be of the normally closed type, and valve elements 24 and 25, of the normally open type, so that window 3 remains in the closed position in the absence of an operating command (pipe 12 under pressure, pipe 7 in communication with the discharge).
A useful improvement of this device with reagrd to its safety may be obtained when window 3 is biased to its closed position by a spring 11 provided between a fixed component of the machine and transmission link 10 to maintain the window in the closed position when the machine is disconnected from the water mains, when the mains pressure collapses, or in the case of a failure of the machine.
Also preferred is the provision of the various contacts for the activation of valve elements 23, 24, 25 and 26 in a single switch, so that the user can cause the window to be opened and closed by selectively acting on a single control element.
As another technical equivalent readily obvious to one skilled in the art, the single hydraulic actuator 8 with its double-acting piston could be replaced by a pair of single-action actuators acting in opposite directions.
The above described invention, specifically the employ of a hydraulic actuator activated by the water mains pressure, may adavantageously be adapted, by the introduction of suitable structural modifications, to other uses, for instance for opening and closing the drawer or other receptacle provided for containing detergents and the like, or for lifting the fixed legs of the appliance off the floor.
Fig. 2 thus depicts the adaptation of the invention to the operation of a detergent drawer 3b instead of the window 3 as in the first embodiment, the rotatable transmission link 10 being replaced in this case by another suitable element 10' operable to transmitt the displacement of piston 9 to detergent drawer 3b.
Shown in fig. 3 is a partially sectioned sideview of a laundry washer of the front-loading type.
In this embodiment piston 9 acts directly on at least one front-mounted caster 3c operable to lift fixed legs 14 off the floor, so that the machine is then solely supported on casters (fixed rear-mounted ones and at least one front-mounted extendable caster). This permits the appliance to be moved without any substantial effort, as it rides along on its rear-mounted fixed casters 15 and the at least one extendable and retractable front-mounted caster 3c.
It may sometimes by considered desirable to employ pneumatic servo-actuators in place of the described hydraulic actuators, in which case a small electrically operated compressor would be required for supplying the compressed air used for operating the actuators. Also in this case, the elements provided for controlling the opening and closing operations or the lifting and loering operations, respectively, would in addition act on the compressor for the supply of compressed air via similar conduits and circuits as explained above with respect to the water mains pressure operated system.
With the sole difference that the various cylinders or pressure chambers would in this case be supplied with compressed air rather than with water at the mains pressure, the remainder of the system might remain substantially unchanged, any modifications required by the employ of compressed air instead of hydraulic pressure being obvious to one skilled in the art.
The actual construction of the pneumatic circuitry and the pneumatic pressure source is per se known and needs not be described for the sake of brevity.
As regards the employ of electro-mechanical actuators instead of hydraulic or pneumatic ones, it is an obvious conclusion for anyone skilled in the art to provide small electric motors acting on gear transmissions 31, 32 as depicted in figs. 5 and 6 in a mechanism for opening and closing the window, or on a gear-and- rach transmission 31, 32 as illustrated in fig. 7 in a mechanism for lifting and lowering the appliance.
In constructions of this type, a gear 31 carried by the electric motor cooperates with the complementary transmission element 32 operatively connected to the element 3, 3b or 3c to be actuated.
The respective elements 3, 3b and/or 3c are thus actuated via the described mechanical transmission means by the activation of the respective motor.

Claims

1. A washing machine, particularly for domestic use, comprising at least one of the following operable elements: a window or door for charging the articles to be washed to the washing tub, a drawer or receptacle for containing the substances to be used for the washing operation, and at least one fixed leg for supporting the machine on the floor, characterized in that at least one of said operable elements (3, 3b, 3c) is adapted to be operated by means of a hydraulic or electro-mechanical or pneumatic servo actuator.

2. A washing machine according to claim 1, characterized in that said hydraulic servo actuator (8) is activated by the pressure of the water supply mains.

3. A washing machine according to claim 2, characterized in that said hydraulic servo actuator (8) substantially comprises a hollow body containing a displaceable hydraulic piston (9) and having its end portions (21,27) hydraulically connected to respective hydraulic valve means (5, 5A) controllable for operating said operable element (3, 3b, 3c) in opposite directions.

4. A washing machine according to claim 3, characterized in that each said valve means (5, 5A) comprises a pair of valve elements (23, 24 and 25, 26, respectively) for controlling two conduits (7, 12) connected to said end portions (21, 27, respectively) of said hollow body, one valve element (23, 25) of each pair being operable to control the supply of water at mains pressure to the associated conduit (7, 12, respectively) while the other valve element (24, 26) of each pair is operable to control communication of the respective conduit (7, 12) with a preferably common discharge conduit (13, 14).

5. A washing machine according to claim 4, characterized in that the valve elements of each pair (23, 24) and 25, 26) are reciprocally operable, so that the first element (23, 25) is open when the second element (24, 26) is closed, and said first element (23, 25) is closed when said second element (24, 26) is open.

6. A washing machine according to claim 5, characterized in that said valve elements (23, 25) for controlling the supply of water at mains pressure to the respective conduit (7, 12) are reciprocally operable, so that one element (23 or 25) is open when the other element (25 or 23) is closed.

7. A washing machine according to any of claims 4 to 6, characterized in that one of said valve elements of each pair (23, 24) and (25, 26) is of the normally closed type, and the other, of the normally open type.

8. A washing machine according to claim 7, characterized in that said each said operable element (3, 3b, 3c) is subjected to the action of a resilient element biasing it to its rest position.

9. A washing machine according to any of the preceding claims, characterized in that said valve means (5, 5A) are electrically actuated.

10. A washing machine according to claim 9, characterized in that said valve means (5, 5A) are electrically connected to a single control element operable to assume one of two possible positions.

11. A washing machine according to any of the preceding claims, characterized in that said servo actuator is of the pneumatic rather than of the hydraulic type, the compressed air required for its operation being supplied by a suitable electrically operated compressor.

12. A washing machine according to claim 1, characterized in that said servo actuator is of the electro-mechanical type comprising an electric motor acting on a wheel (31) formed with teeth or other motion transmission means cooperating with complementary transmission elements (32) themselves operatively connected to said operable elements (3, 3b, 3c).