COOKING APPLIANCES WITH OPTICAL INDICATION OF OPENING OF THE GAS TAP

5 TECHNICAL FIELD

The present invention relates to a control switch harness for the lighting of burners of a cooking range, couplable in use to the gas taps feeding the burners and provided with an optical light indication when the gas 10 tap is open.

BACKGROUND ART

It is known that control devices for the burners of a cooking range (either of the fitted type, or of the type belonging to a combined household appliance, e.g.

15 comprising one or more oven cavities and/or a dishwasher) may comprise, for each burner, a gas tap and a switch harness element provided with a microswitch, the actuation of which supplies voltage to a service lighter circuit of the cooking range, of known type,

20 which produces a seguence of sparks at one or all burners .

Generally, the gas tap is provided with an axially moveable, rotary control shaft or stem, provided in use with a control knob, the rotation of which allows the 25 dispensing of combustible gas to the burner.

In the device known from EP1194720B1, the axial movement of the stem/knob assembly is used to actuate the microswitch, thus producing the generation of the lighting spark at the same time of the gas delivery.

If an optical indication of the gas tap opening is reguired, a supplementary device must be provided, e.g. eguipped with LED, to be coupled to a gas tap.

Electricity is supplied to each module by means of appropriate wiring. This makes the wiring very complex and costly and weighs on assembly operations and time.

DISCLOSURE OF INVENTION

It is an object of the present invention to overcome such drawbacks by providing a lighting control switch harness for burners of a cooking range couplable to the burner feeding gas taps and provided with an optical light indication that gas tap is open, the construction and wiring of which is simple and reliable, and which is compact and relatively cost-effective.

The present invention thus relates to a lighting control switch harness for the burners of a cooling range, as disclosed in claim 1.

In particular, the lighting control switch harness of the invention comprises a plurality of elements connected to one another and each comprising a body couplable in use to a respective gas tap and closed by a cover at least partially pervious to light and a printed circuit underneath the cover and carrying one or more light sources, e.g. LEDs .

According to a feature of the invention, each switch harness element further comprises a first switch accommodated within the body and comprising at least one fixed contact connected to the printed circuit, a mobile contact and first means carried by the body so as to be operatively couplable in use to a mobile stem of the gas tap for integrally rotating therewith and conseguently taking the mobile contact towards the at least one fixed contact; and a second switch accommodated within the body and comprising a fixed contact, a mobile contact and second means carried by the body so as to be in use operatively couplable to the mobile stem of the gas tap for translating parallelly thereto and conseguently taking the mobile contact towards the fixed contact.

The elements of the switch harness are mechanically and electrically connected to one another only by means of three wires passing through the body of the various elements, a first wire being connected to a first contact of the second switch of each element, a second wire being connected to the mobile contact of the first switch of each element, and a third wire being connected to a second contact of the second switch of each element, while the printed circuit of each element is further electrically connected to the first wire.

In this manner, by using only three connection wires, two microswitches acting on two different circuits can be incorporated in a single switch harness element, one on the service lighting circuit of the cooking range and the other on the feeding circuit of the light sources, which provide the desired optical indication that the gas tap is open, which is obtained on the printed circuit .

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will be apparent from the following description of a preferred embodiment, exclusively provided by way of non-limitative example, with reference to the accompanying drawings, in which:

- figure 1 shows a three-guarters , axonometric view of an element of the switch harness according to the invention fitted on a gas tap, underneath thereto;

- figure 2 shows a simple wiring diagram of the lighting harness element in figure 1;

- figure 3 diagrammatically shows the lighting harness according to the invention, and

- figures 4, 5 and 6 show the lighting harness element in figure 1 with parts gradually removed.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to figures from 1 to 6, numeral 1 indicates a lighting control switch harness (figure 3) for the gas taps of burners 2 (of which only one is shown in figure 2) of a cooking range (known and not shown for the sake of simplicity) .

The switch harness 1 comprises a plurality of elements 3 connected to one another mechanically in series and electrically in parallel, according to a feature of the invention, by only three electric conductor wires, indicated by numerals 4, 5 and 6, respectively . Each element 3 comprises a body 10, couplable in use to a respective gas tap 11 and closed by a cover 12 (figure 1) at least partially pervious to light, e.g. because it is provided with at least one window 13, ring-shaped in the non-limitative example.

A printed circuit 14, carrying a plurality of LEDs 15 arranged in a circle at the ring-shaped window 13, about the gas tap 11, is arranged in the body 10 immediately under the cover 12; it is apparent that any other position of the LEDs 15 or of other light sources according to a different shape and position of the window 13 is possible.

The body 10 is cup-shaped and delimited, on the side opposite to the cover 12, by a bottom wall 16 (figures 4-6) facing the cover 12 with the interposition of the printed circuit 14. A first switch 20 and a second switch 21 are accommodated as integral part of each element 3 in the body 10 arranged under the printed circuit 14, between the latter and the bottom wall 16.

The switch 20 comprises at least one fixed contact

22 connected to the printed circuit 14, a mobile contact

23 and first means 24 carried by the body 10 so as to be in use operatively couplable to a mobile stem 25 (known) of the gas tap 11 for turning integrally with the same and conseguently taking the mobile contact 23 towards the at least one fixed contact 22.

The switch 21 comprises in turn a fixed contact 27, a mobile contact 28 and second means 29 (figures 4 and 6) carried by the body 10 so as to be in use operatively couplable to the mobile stem 25 of the gas tap 11 to translate parallelly to the same and conseguently take the mobile contact 28 towards the fixed contact 27.

According to the invention, the elements 3 are mechanically and electrically connected to one another only by means of the three wires 4, 5 and 6, passing through the body 10 of the various elements 3. In particular, the wire 4 is connected to a first contact 28 of the switch 21 of each element 3, in the non- limitative case in point to the mobile contact 28, while wire 5 is connected to the mobile contact 23 of the switch 20 of each element 3, and wire 6 is connected to the fixed contact 27 of the switch 21 of each element 3. Furthermore, the wire 4 is also electrically connected in permanent manner to the printed circuit 14 of each element 3 by means of a metallic contact terminal 30 (figure 6) carried by the body 10.

On the printed circuit 14 an electric power supply circuit 31 for the LEDs 15, substantially of known type, is obtained in known manner, the electric power supply of which is controlled by the switch 20.

The bottom wall 16 is provided with a hole 33 (figure 5) designed to couple in use with the gas tap 11, e.g. snappingly, from the side of the mobile stem 25, so as to be thoroughly crossed in use by the mobile stem 25 itself, which further also crosses the cover 12 facing the bottom wall 16 and the interposed printed circuit 14 by virtue of the conformation of the printed circuit 14 and the presence of a second hole 34 obtained passing through the cover 12, coaxial with the hole 33.

The means 24 consist of a ring idly guided into the first hole 33 and eguipped radially on the inside thereof with (known) angular fastening means 35 to the mobile stem 25 and on the radially outside thereof with an overhanging radial appendix 36 which extends into the body 10 and cooperates with the mobile contact 23, which consists of an elastic metal blade carried by the bottom wall 16 of the body 10 arranged on edge, i.e. with the laying plane thereof perpendicular to the wall 16 and electrically connected to wire 5.

The means 29 consist of a cup-shaped bush mounted coaxially with the ring 24, with the interposition of a helical spring 37 (visible in figure 5 where the bush 29 is removed) , which bush 29 is thoroughly and slidingly guided into the second hole 34 and designed to be thoroughly crossed, in use, by the mobile stem 25.

In particular, the bush 29 is mounted overhangingly protruding from the cover 12 (figure 1) and is provided with a radial arm 38 (figure 4, 6) cooperating with the mobile contact 28 and arranged angularly offset with respect to the radial appendix 36 of the ring 24. The mobile contact 28 consists of an elastic blade overhangingly supported flat by the bottom wall 16, i.e. with its laying plane parallel to the latter, and electrically connected to the wire 4. In the illustrated example, the fixed contact of the switch 20 consists of a pin 22 carried by the printed circuit 14 perpendicularly to the bottom wall 16 of the body and electrically connected to the printed circuit (14) itself; the latter, as previously mentioned, is further electrically connected to the wire 4 by means of the contact terminal 30.

The body 10 is further internally provided with fixing means 50 for the wires 4, 5, 6, constituted by compression cocking elements which, working in cooperation with the fixed and mobile contact terminals of the switches 20,21, prevent the wires themselves from axially sliding through the body 10 of each element 3, thus maintaining the reciprocal position of the elements 3 along the entire extension of the switch harness 1.

In use, the switch harness 1 is mounted on the cooking range of the electric household appliance, by fitting each element 3 integrally to a gas tap 11.

In order to light a burner, the user must take a control knob of the tap 11 (known and illustrated by a dashed line in figure 1), to then turn it, by holding it pressed, to a position corresponding to the reguired gas flow: this movement causes a translation and subseguent rotation of the stem 25. The pressure on the knob (not shown) is also transmitted to the bush 29, underneath it, making the switch 21 close and conseguently producing in known manner the power supplying of the lighting circuit (known and not shown) of the burners 2. At the same time, the rotation of the stem 25 produces the rotation of the ring 24 with conseguent delivery towards the burner 2, by the gas tap 11, of a flow of gas fuel, e.g. methane, and simultaneously the closing of the switch 20, with conseguent electric power supply of the circuit 31 carried by the printed circuit 14 and simultaneous lighting of all LEDs 15. Through the window 13 a ring-shaped lighting is thus created about the knob (not shown) of the gas tap 11, which remains actuated also when the knob is released, if it is not returned to the closed tap position, while the switch 21, on the other hand, opens by elastic return of the blade 28, making the generation of sparks on the burner 2 cease.

When the gas tap 11 is closed by turning the knob in the other sense, the switch 20 is opened turning the light sources off, in the case in point the LEDs 15. In this manner, when the gas is delivered to the burner 2, the knob of the corresponding gas tap 11 is lit, warning the user that the gas is delivered into the atmosphere.

It is apparent that the switch harness 1 can be adapted with changes obvious for a person skilled in the art so as to let the LEDs 15 light up gradually as the stem 25 is turned instead of making them light up all at the same time. For this purpose, it would be sufficient, for example, to replace the two-contact switch 20, with a multiple contact switch, in which the mobile contact is a brush which progressively reaches a plurality of fixed contact, appropriately connected to one another.