DESCRIPTION

Field of the invention

The present invention relates to a device for selecting the operating programmes of an appliance, in particular of an electrical household appliance, which incorporates the auto switch-off function. Selecting devices of this type are commonly called simply selectors, and accordingly the present invention relates to a selector provided with auto switch-off function, i.e. for switching off the appliance automatically, which entails total disconnection of the electric power supplied from the mains.

Prior art

The use of selectors connected to electronic control cards that incorporate both the power switch ON/OFF function and the function of selecting the operating programme of the electrical household appliance, settable by the user, are currently known on the market and are commonly used in the electrical household appliances sector, such as mainly washing machines but also dishwashers, tumble-dryers and similar electrical household appliances.

In the known devices, the two functions are controlled and performed by two different, separate circuits: one circuit dimensioned for switching power loads up to 16 amperes at the nominal mains voltage (220-230 V), the other for managing a digital output with Gray code, i.e. a fixed-length binary code well known by a person skilled in the art of electronic or electromechanical devices, at low operating currents and voltages.

In the known devices that are used more widely, both circuits are controlled by means of a cam that turns as a result of actuation, in particular of rotation, by the user, of a control knob located on the control panel of the electrical household appliance. In more detail, the first step of rotation of the knob causes closure of two power contacts and we thus have switching from the OFF position to the ON position of the electrical household appliance, which is thus live, while successive positions of the knob, which are reached by successive rotations of said knob, alter the digital output, and therefore the operating programmes of the electrical household appliance, according to a code predefined by the design and connected with the morphology of the control cam inside the selector.

During selection of the operating programmes of the electrical household appliance the power circuit is always closed, and therefore the electrical household appliance is always in the ON condition.

Return to the OFF position of the electrical household appliance only occurs as a result of intervention by the user, who operates the knob again, bringing the selector back to the OFF position and thus opening the contacts of the power circuit.

The technical solution known to date and illustrated up to now thus necessarily involves intervention by the user to be able to switch off the electrical household appliance completely, i.e. to bring the electrical household appliance to the OFF condition by opening the power circuit that supplies the machine at the mains voltage.

In fact, the selector remains in its coding position selected at the beginning of the operations until further rotation of the knob to the initial OFF position is effected manually, by the user.

This clearly involves the drawback of having indefinite power consumption by the electrical household appliance even when it has finished its operating cycle and is now in the stand-by condition, in which it is non-operating but still live.

Summary of the invention

The main problem to be solved by the present invention is therefore to provide a selector that overcomes these and other drawbacks of devices of the type known from the prior art.

In particular, the present invention aims to provide a selector which, while maintaining the functions of manual setting of the operating programme and of manual switching on and off, also includes an auto switch-off function, specially controlled by the control electronics of the machine.

In connection with these problems, the present invention aims to provide a selector that is compatible "pin to pin", where pin means the connecting contact between the selector and the card, with the existing electronic control cards in use on the majority of electrical household appliances, and that is mechanically compatible with the control knobs currently in production.

Thus, the selector according to the present invention can be connected to the electrical household appliance without requiring any modification of the design of the seating of the conventional selector.

Another aim of the present invention is to provide a selector that makes it possible to use at least some of the components currently used in devices without an auto switch-off function of the type known from the prior art, with obvious advantages in terms of mechanical and electrical reliability, as well as safety.

These and other aims that will become clearer from a detailed description of the present invention, given here for purposes of illustration and non-limiting, are achieved by a selector for switching-on, switching-off and selection of the operating programmes of an appliance, in particular of an electrical household appliance, comprising means for automatic opening of the power supply circuit at the end of the selected operating programme.

Brief description of the drawings

Further characteristics and advantages of the present invention will become clearer from the following detailed description, given as an example and non- limiting, and illustrated in the appended drawings in which:

Fig. 1 shows an exploded view of the components of the selector according to the present invention;

Fig. 2 shows a detail of the selector according to the present invention in an operating condition corresponding to a situation in which the user has moved the selector manually to the OFF position, corresponding to the "zero" position of the knob;

Fig. 3 again shows a detail of the selector according to the present invention in the same configuration as in Fig. 2, in which a further structural element can be seen; Fig. 4 shows a detail of the selector according to the present invention, in particular a portion of the automatic means for opening the power circuit;

Figs. 4A and 4B show respectively a first configuration and a second configuration of the actuator that causes automatic switch-off; Figs. 5A and 5B show, in a perspective, partially dismantled view, the selector according to the present invention in the operating condition in which the selector is in the ON position;

Figs. 6A and 6B show, in a perspective, partially dismantled view, the selector according to the present invention in the operating condition in which the selector is in the PULSE condition;

Figs. 7A and 7B show, in a perspective, partially dismantled view, the selector according to the present invention in the operating condition in which the selector is in the OFF condition.

Detailed description of the invention

With particular reference to Fig. 1 , which shows the selector 100 according to the present invention in an exploded view, said selector comprises a box-shaped enclosing casing 10 which houses some components assigned to connection of said selector to the electronic card of the electrical household appliance, such as for example the contact pins 11 and further connecting elements 12.

Said enclosing casing 10 houses a function selector 20, which in the example shown in the figures consists of a Gray-code selector comprising a substantially cylindrical axial body 21 connected integrally to a disk 22 that develops in a plane substantially horizontal and perpendicular to said cylindrical axial body 21 whose axis A defines the rotation axis of said disk 22.

When the function selector 20 is assembled in the enclosing casing 10, and the enclosing casing is assembled with the electronic card of the electrical household appliance, the cylindrical body 21 of function selector 20 is in a substantially vertical position, and is connected to the knob of the electrical household appliance that can be moved manually by the user.

The rotation of the knob of the electrical household appliance by the user thus causes a rotation of the function selector 20.

The disk 22 has a top surface and a bottom surface, where the bottom surface is the one that is turned towards the bottom of the enclosing casing 10, and therefore towards the electronic card when the device is assembled on the electrical household appliance, while the top surface is the opposite surface, facing upwards according to the orientation shown in the figures. In the present description, the terms "upper" and "lower" as well as "top" and "bottom", "vertical" and "horizontal" will be used with reference to the orientation of the device shown in the accompanying drawings, although in actual operation the device will also be able to have a different spatial orientation. Thus, for example, it will be said that axis A of rotation of the function selector 20 is a vertical axis, and vertical direction means the direction of axis A that can be seen in Fig. 1 , while the horizontal direction will be identified as the direction orthogonal thereto.

With vertical direction and horizontal direction thus defined, the terms "top" and "bottom", "upper" and "lower" do not require further definition as they will be referred to this system of orientation.

Returning to the description of the device, said disk 22 of function selector 20 comprises, corresponding to the outer edge of the upper face, a series of teeth 22a that thus produce an alternation of peaks and valleys, and corresponding to the inner edge, as can be seen in Fig. 2, a further tooth 23 that will correspond to the zero position of the selector, as will be clearer from the following illustration of the operation of the device.

The selector according to the present invention then comprises means for automatic opening of the power supply circuit of the electrical household appliance to which the selector is connected.

Said means comprise in particular a series of components 30, 40, 60, 70 able to interact with one another, with said function selector 20, and with the contacts 13, 14 of the circuits of the electrical household appliance, so that the user can act manually on the knob of the electrical household appliance causing said elements to close the power circuit supplying the electrical household appliance by selecting the desired operating programme, and in such a way that opening of the power circuit supplying the electrical household appliance at the end of the operating programme can take place both manually under the action of the user by rotating the knob of the electrical household appliance, and automatically under the action of the electronic control unit of the electrical household appliance and via said means.

Among said components, a mechanical reset 30 is connected to said function selector 20, and can only move vertically relative to the latter. In particular, the vertical movement of said mechanical reset 30 is determined by the presence of a tooth 33 able to oppose tooth 23 of said function selector 20. As can be seen in particular from Fig. 2, when the two teeth 23 and 33 are in an opposed position, owing to the slope of their sides that forms a slide that facilitates the relative sliding of the two elements, the mechanical reset 30 moves upwards. The force required for bringing the two opposed teeth 23 and 33 in the position in Fig. 2 is supplied by the user, acting on the knob and rotating it.

Said mechanical reset 30 comprises in its turn a substantially cylindrical, hollow bottom portion for enclosing said cylindrical axial body 21 of said function selector. Said mechanical reset 30 has in addition a pair of stems 32 that extend upwards in a substantially vertical direction. In the embodiment shown as an example, said vertical stems 32 are two in number and are positioned in a position diametrically opposite to one another.

Said components further comprise a power actuator 40.

The power actuator 40 consists of an element that also has a hollow cylindrical central portion 41 , to which a disk-shaped base element 42 is connected, from which two bridge pieces 43 extend vertically and in a position diametrically opposite to one another.

The power actuator 40 is thus configured so that it can be inserted in said mechanical reset 30 in such a way that said stems 32 are inserted into said vertical bridge pieces 43. The coupling thus created between the power actuator 40 and the mechanical reset 30 only permits relative movements of translation of the two elements in the vertical direction relative to one another.

On the bottom surface of said disk-shaped base element 42 there is a series of teeth 42a that can interact with the teeth 22a provided on said disk 22 of the function selector 20.

When the complex of elements consisting of said function selector 20, the mechanical reset 30 and the power actuator 40 is inserted in said enclosing casing 10, the contacts 13 of the power circuit and the contacts 14 of the low-voltage circuit for programme selection are in contact with the top surface of said disk- shaped base element 42 of said power actuator 40, as can be seen in the figures from 5A and 5B to 7A and 7B. A first cover 50 is closed on said enclosing casing 10 holding the elements described so far.

Said first cover 50 has holes that permit passage of said vertical bridge pieces 43 of said power actuator 40, inside which, as already mentioned, said vertical stems 32 of said mechanical reset 30 are housed.

The selector according to the present invention further comprises an actuator 60 that is able to operate a fastening-releasing device 70.

Said actuator and said releasing device are advantageously positioned above said first cover 50 so that a pair of fastening teeth 71 forming part of said releasing device interacts with said bridge pieces 43 that project upwards from said first cover 50.

More particularly, said actuator 60 is constituted, in the example shown here as a non-limiting example, of an electromechanical actuator, in particular of a solenoid 60 comprising an actuating arm 61 which is able to effect a horizontal movement of a release lever 72, forming part of said fastening-releasing device 70, as a result of an electric pulse.

In the alternative embodiment shown as an example in Fig. 4B, the solenoid comprises a protective conductor with thermal autoregulation indicated by the acronym PTC (Positive Temperature Coefficient) and known on the market, mounted in series with the winding of the solenoid. This ceramic element can cut off the current flowing through the winding in case of failure, to the electric control system. In the absence of this protection, in fact, the wire of the solenoid could overheat and even melt, producing smoke (although still meeting the standard requirements for product safety) and causing permanent breakage of the device. This solenoid is controlled directly by the electronic control unit of the electrical household appliance, and therefore the electric pulse can be sent to the solenoid under the control of said electronic control unit.

The release lever 72 can be seen in particular in Fig. 4.

Said release lever 72 moves the pair of fastening teeth 71 that can be inserted in said vertical bridge pieces 43 of said power actuator, preventing the latter from moving downwards. Still referring to Fig. 4, it will be seen that the release lever 72 is connected to solenoid 60, and that a compression spring 73 holds the fastening teeth 71 in an operating position in which they lock the vertical bridge pieces 43 in a raised position, while actuation of the solenoid, with consequent movement of release lever 72, displaces said fastening teeth 71 to a non-operating position in which they do not interact with said vertical bridge pieces 43.

The operation of the selector according to the present invention is as follows.

The power actuator 40 and the mechanical reset 30 can move vertically relative to the body 10 of the selector, while the function selector 20 turns when operated by the user as it is integral with the control knob of the electrical household appliance. Thus, as a result of actuation of the knob, the function selector 20 turns, and its rotation causes upward movement of the power actuator 40 by the effect of opposition of teeth 22a of said function selector 20 with teeth 42a of said power actuator 40.

Thus, at each step of rotation of the knob, the power actuator 40 moves upwards, thereby also raising the mechanical reset 30 that is integral with said power actuator 40.

However, owing to the presence of the opposed teeth 23 and 33, rotation of the function selector 20 corresponds to an upward movement of the mechanical reset 30 only and exclusively when the operator moves the knob manually to the OFF position, corresponding precisely to alignment of the two opposed teeth 23 and 33. We shall return to this aspect of the operation of the device later.

The upward movement of the power actuator 40, which occurs corresponding to the rotation of the knob corresponding to selection of an operating programme of the electrical household appliance, causes the power contacts 13 to close, thus supplying the electrical household appliance with mains voltage, as can be seen in Figs. 5A and 5B. In this operational configuration of the selector that corresponds to selection of a programme by the user, the bridge pieces 43 of said actuator 40 will be caught on the fastening teeth 71 of the fastening-releasing device 70, which keeps them in the raised position throughout the operation of the electrical household appliance until the end of the programme. This position of the fastening teeth 71 is guaranteed by the action of the compression spring 73 housed between said release lever 72 and a second fixed cover 80 for containing said solenoid 60 and said release lever 72.

Accordingly, in this configuration the user can rotate the knob and alter the programme setting of the electrical household appliance with the power actuator 40 remaining in the raised position shown in Figs. 5A and 5B that corresponds to an ON operating condition of the electrical household appliance in which the power supply circuit is closed.

If the user should wish to interrupt the operation of the electrical household appliance manually, bringing it manually to a non-operating OFF condition, he can operate the knob, turning it to the OFF position. Corresponding to this position of the knob, tooth 23 of said function selector 20 moves to correspond to tooth 33 of said mechanical reset 30. This last-mentioned element, the mechanical reset 30, is thus pushed upwards to the position shown in Fig. 2, and the stems 32 slide into the bridge pieces 43.

Owing to the bevelled configuration of the bottom surface of the fastening teeth 71 , when the stems 32 are pushed upwards to reach the end of travel shown in Fig. 3, the fastening teeth 71 are pushed out of the bridge pieces 43, in opposition to the force exerted by the compression spring 73, releasing said bridge pieces and thus allowing the power actuator 40 to move downwards, pushed by the elastic action of the power contacts 13.

When the power actuator 40, and with it the mechanical reset 30, return to the bottom position in which the tips of teeth 42a of said power actuator 40 are inserted in the valleys defined by the teeth 22a of said function selector 20, the selector will be in the OFF configuration shown in Figs. 7A and 7B, in which the contacts 13 of the supply circuit are open, and the electrical household appliance is not live.

Thus, the function of bringing the electrical household appliance to the OFF condition manually is achieved by simple operation of the knob on the part of the user.

Returning now to the situation in which the operating condition of the electrical household appliance is the ON condition shown in Figs. 5A and 5B, the means for automatic opening of the power circuit that supplies the electrical household appliance with mains voltage operate in the following way.

Assuming that in the ON configuration the fastening teeth 71 are inserted in the bridge pieces 43 and prevent the power actuator 40 from moving downwards causing opening of the contacts 13 of the power circuit, when the electronic control unit of the electrical household appliance detects the end of the operating programme that has been set, said control unit sends a pulse to solenoid 60 that moves the actuating arm 61 horizontally, which in its turn moves the release lever 72 horizontally, which retracts the fastening teeth 71 , releasing said bridge pieces 43, which are thus free to move downwards together with the power actuator 40, pushed by the spring 62.

Again in this case, the downward movement of the power actuator 40 causes opening of the contacts 13 and therefore opening of the supply circuit of the electrical household appliance, which therefore switches automatically to the OFF condition without the operator having to intervene manually by operating the knob. It has thus been shown that the selector according to the present invention makes it possible to incorporate in a single device both the manual OFF function conventionally performed by the selectors currently used on electrical household appliances, and an innovative auto switch-OFF function that currently is not performed by the known selectors, so that the electrical household appliances remain under power in a stand-by condition, involving energy consumption even at the end of the operating programme of said electrical household appliance.

Thus, it has been shown how the selector for switching-on, switching-off and selection of the operating programmes of an appliance, in particular of an electrical household appliance, comprising means for automatic opening of the power supply circuit at the end of the operating programme selected, achieves the purpose and the proposed objects.

In particular, it has been illustrated how the selector according to the present invention makes it possible to combine in a single, extremely compact device, and which can be used together with an electronic card of the type already in use on electrical household appliances, without requiring any modification, and being compatible pin-to-pin with the selectors already known only now also providing an auto switch-off function, not performed by the existing selectors.

Numerous changes can be made by a person skilled in the art while remaining within the scope of protection of the present invention.

The scope of protection of the claims should therefore not be limited by the illustrations or by the preferred embodiments shown as examples in the description, but rather the claims must comprise all the characteristics of patentable novelty deducible from the present invention, including all characteristics that would be treated as equivalent by a person skilled in the art.