EP0600780A1 - Control switch for a domestic cooking appliance - Google Patents

Abstract

Switch for an element heating through a non-pierced glass plate of a domestic cooking appliance (1), in order to change over at least one relay (16) closing or opening an electrical circuit (19) by means of a small permanent magnet (11). This relay is a magnetic relay mounted in a fixed chassis (17) immobilised against the face (18) of the glass plate (7) situated towards the inside of the appliance, and the switch (8) includes an operating knob (9) being applied against the opposite face (15) of the plate turned outwards and accessible to the user of the appliance. The switch is characterised in that this knob is able to be driven freely in rotation with respect to the plate around a stud (10), the location of which on the face of the plate is defined so as to arrange the knob in proximity to the relay mounted against the other face, and includes, the permanent magnet (11), offset radially in a plane passing through the stud. In this way, consequent on the rotation of the knob on the stud, the magnet is brought in line with the relay, causing the latter to close, or is moved away with respect to this relay, the latter then automatically returning to the open state, the stud (10) locating the operating knob (9) around which the rotation of this knob takes place, interacting with an open indentation (12) formed in a hollow at the centre of the latter in its surface (13) which is applied against the plate (7).

Description

The present invention relates to a switch intended in particular to allow the electric power on or off of a heating element for oven or hob, by closing or controlled opening of a supply circuit containing this element and capable of 'be connected or disconnected with an appropriate voltage source.

Numerous embodiments of electromechanical switches are already known in the art, generally comprising an axis at the end of which is fixed a control button making it possible to control the rotation of this axis, the latter being capable of driving a wafer with it or similar provided with at least one electrical contact ensuring, following its displacement, the closure on a source of electrical voltage of a circuit in which is mounted a heating element, of the electrical resistance or radiation lamp type. As is well known, the wafer usually has a series of separate studs for graduation and in particular to regularly increase the intensity of the current flowing through the element. heating and consequently to increase the calorific energy which it delivers.

But in modern embodiments of ovens or domestic cooking plates, it is customary for aesthetic reasons in particular, to use a material of the kind of a ceramic glass, either to constitute the surface of the plate itself, the heating elements located under it radiating through this plate on which are arranged the containers containing the food to be cooked, either even to form a strip or the frame of an oven whose front including the pivoting door to access the he interior is also glazed.

Under these conditions, to connect the control button driving the axis of the switch and the organs of the latter which carry the contacts ensuring the electrical tensioning of the heating elements connected by these contacts to the voltage source, it is necessary to drill the glass plate or strip fixed in front of the metal frame of the cooking appliance, which has a double disadvantage, on the one hand by weakening the glass at the right of the hole made for the passage of the axis, on the other part by detracting from the overall aesthetics of this device.

The presence of several of these holes - in general, an appliance of this kind comprises several switches providing separately distinct functions for the control of separate heating zones in a hob or else different heating stages in an oven - increases still these drawbacks, by further providing through the glass bushings in which may infiltrate liquids or various residues, which in the long term may deteriorate the correct operation of the corresponding switches.

The present invention relates to a switch which avoids these drawbacks, by eliminating any drilling in the plate or the strip of glass, the transmission of control orders, in particular opening or closing of an appropriate electrical circuit being effected at through the glass without affecting its integrity.

To this end, the switch considered, for controlling the switching on or off of an electrical element, in particular a heating element, through a strip or a glass plate not pierced by a domestic cooking appliance, to ensure the switching of at least one relay closing or opening an electrical circuit containing this element, by means of a small permanent magnet, this relay being a magnetic relay mounted in a fixed frame immobilized against the face of the glass plate situated towards the inside the device, and the switch comprising an operating button which is applied against the opposite face of the plate facing outwards and accessible to the user of the device, is characterized in that this button is suitable for be freely driven in rotation with respect to the plate around a stud whose location on the face thereof is determined so as to arrange the button near the relay mounted against the other face, and comprises, offset radially in a plane passing through the stud, the permanent magnet, so that, following the rotation of the button on the stud, the magnet is brought to the right of the relay by causing the automatic tilting and closing of the latter, or else be deported with respect to this relay, the latter then automatically returning to the open state, the stud ensuring the location of the operating button, around which the rotation of this button is ensured , cooperating with an open imprint, hollowed out in the center of the latter in its surface which is applied against the plate.

Preferably but not exclusively, the magnetic relay is a relay of the type known in the art under the name of "Reed" relay, comprising a sealed capsule, generally made of glass, containing two lamellae forming a spring, aligned one with the 'other while presenting between their ends substantially in the center of the capsule a space which separates them mutually, these strips being made of a ferromagnetic material. At their opposite ends, these strips cross the wall of the capsule to form the connection terminals of the relay in the circuit.

At rest, the two strips are normally spaced from each other due to their own rigidity and their mounting vis-à-vis the walls of the capsule, the relay being open. On the other hand, when a permanent magnet is approached from the capsule, possibly a coil creating a magnetic field, poles of opposite polarities are created at the ends of the strips so that the latter attract each other by closing the relay. Again, when the magnet is moved away, the magnetic force between the lamellae decreases, or even disappears, until they separate, thus opening the relay returned to its initial position.

Advantageously, the face of the glass plate directed towards the outside has a plurality of marks, regularly distributed in the surface of the plate around the center of the stud on which the operating knob pivots, to allow an appropriate location of the magnet. permanent carried by this button against the plate, each corresponding mark, on the opposite face of the plate, to the mounting of a separate magnetic relay in such a way that the rotation of the button around the stud causes the successive closing or opening of each relays associated with these benchmarks.

According to a particular characteristic, each mark provided in the face directed towards the outside of the glass plate can also be associated, near the corresponding magnetic relay, with a light indicator mounted in the circuit comprising this relay, so that the Closing it simultaneously causes this indicator to light up.

According to another characteristic, the operating button comprises a positioning index provided in its lateral surface and extending in the radial plane containing the permanent magnet, this index materializing, in front of each mark on the glass plate, the position of the magnet to the right of the magnetic relay associated with this mark.

In a first embodiment of the switch considered, the stud came from manufacture with the glass plate and projects into the face of the latter facing outwards from the device.

In this first variant, the operating button is removable and completely separate from the plate, the user, grasping the button, then applying it against the glass plate so as to engage the nipple in the impression, then causing the Controlled rotation of the button to move the permanent magnet it has with respect to the relay to be opened or closed.

In another embodiment of the invention, the stud around which the rotation of the operating button is ensured is fitted against the face directed towards the outside of the glass plate.

In this second variant, the stud may in particular be constituted by a projecting element, formed in the center of a plate glued against the glass plate by by means of a layer of adhesive of the epoxy adhesive type or the like.

Also in this variant, the operating button can be removable or else mounted against the wafer while being made inseparable from the latter while remaining free to rotate with respect to the stud. In the latter case, the plate has a peripheral edge folded in the direction of the stud and under which engages an external flange provided on the button in the vicinity of its surface which is applied against the glass plate.

According to another characteristic advantageously implemented in this second variant, the plate comprises, arranged coaxially with the stud, a washer integral or fixed against the plate and comprising notches angularly spaced, these notches cooperating with a lug forming a pawl carried by the button, so as to immobilize it in separate successive positions, corresponding to the marks provided in the face directed towards the outside of the glass plate.

• La Figure 1 est une vue schématique en perspective partielle d'un appareil de cuisson domestique comportant un bandeau en verre sur lequel sont disposés des commutateurs selon l'invention, pour la commande des foyers de chauffage d'un tel appareil.
• La Figure 2 est une vue de détail à plus grande échelle, en perspective et en coupe partielle, d'une commutateur utilisé dans l'appareil selon la Figure 1.
• La Figure 3 est une autre vue en coupe transversale d'une variante de réalisation.
• La Figure 4 est une vue en perspective du commutateur selon la Figure 3.

Other characteristics of a switch established in accordance with the invention will become more apparent from the following description of several exemplary embodiments given by way of non-limiting example, with reference to the appended drawings, in which:

• Figure 1 is a schematic partial perspective view of a domestic cooking appliance comprising a glass strip on which are arranged switches according to the invention, for controlling the heating zones of such an appliance.
• Figure 2 is an enlarged detail view, in perspective and in partial section, of a switch used in the device according to Figure 1.
• Figure 3 is another cross-sectional view of an alternative embodiment.
• Figure 4 is a perspective view of the switch according to Figure 3.

In FIG. 1, the reference 1 generally designates a cooking appliance which, in this example, consists of what is commonly known as a "cooker", comprising an upper hob or hob 2 provided with heating hearths 3 distributed in the surface of this table and, under the latter, an oven 4, sketched on the drawing, in particular by the representation of the pivoting door 5 which closes the front face of this oven, maneuverable by a transverse handle 6 .

Between the hob 2 and the oven 4, the device comprises, in its front part, above the door 5 of this oven, a transverse strip 7 which, in current embodiments is very generally a strip of a glass, in particular of the vitroceramic type, to enable it to resist adequately the temperatures to which it may be subjected in operation of the apparatus.

Of course, it should be emphasized that the invention applies regardless of the type of cooking appliance considered, the example of a cooker being given only for information. In particular, it also relates to the actual cooking plates, the surface of which is itself formed by a glass ceramic glass plate, the switches which control the energization of the heating elements of each household 3, being in this case arranged, not on a strip separate from the plate as illustrated in Figure 1, but directly on this last in the vicinity of the front edge thereof. Likewise, the invention applies to baking ovens, in particular built-in ovens, not comprising an upper baking plate but only a glass strip on the front face, like that designated under the reference 7 in FIG. 1, this strip extending the surface also glazed of the pivoting door 5 of the oven by achieving a continuity which contributes appreciably to the aesthetics of the assembly.

Whatever the type of device thus envisaged, the invention aims to provide switches such as 8 in the glass strip 7 or the like, making it possible to control the heating elements of the hearths 3 of the plate or the resistances of the oven, or even functions performed by the latter, during the cooking phase or, if necessary, automatic cleaning by pyrolysis. In particular, these switches are arranged so that the opening or closing control of relays mounted in the supply circuits of these homes or resistors, in order to put them off or on from an appropriate source according to the desired program, can be carried out without it being necessary beforehand to pierce the plate 2 or the glass strip 7 for the passage of an axis causing an electrical contact as in the conventional switches, in themselves well known in the technique.

To this end and according to the invention, an operating button 9 is used which is capable of undergoing rotation around a stud 10 carried by the glass strip 7 projecting towards the face of the latter facing outwards from the device 1, accessible to the user, this button being provided with a small permanent magnet 11 and with a position marking index 9a, the rotation of the button 9 when it is applied to the stud 10 taking place around the latter partially engaged in an open cavity 12, recessed in the surface 13 of the button which is applied against the face in look 15 of the banner 7.

Figure 2 illustrates in more detail a first embodiment of a switch according to the invention. In the latter, the stud 10 constitutes a protrusion coming from manufacture with the strip 7 and thus achieves a slight protuberance in the corresponding face of the strip. In this same variant, the operating button 9 is completely separable from the strip 7 and removably mounted relative to the latter as shown in FIG. 1, the same button 9 being able to be indifferently used to successively or optionally control the various switches 8 provided in the strip 7. In periods of non-use, the button 9 can be stored in a housing 14 arranged for example on the side of the strip 7.

In the example shown, the strip 7 comprises four neighboring switches 8, corresponding to the four heating zones 3; it is quite obvious, however, that the number of switches is completely indifferent to the invention itself as, for the reasons already stated, to the type of cooking appliance, provided that this comprises a plate or strip of glass bearing these switches and whose integrity it is only important to respect without piercing their thickness.

In FIG. 2, the switch shown comprises a relay 16 mounted in a chassis 17 very schematically 'illustrated and of which consequently the particular structure has no incidence, this chassis being only immobilized against the face 18 of the glass strip 7, opposite to the face 15 and therefore directed towards the interior of the device and therefore normally inaccessible to the user.

This relay 16 is a magnetic relay, preferably of the "Reed" relay type, the representation of this relay on the drawing having been deliberately simplified to make it clear only that it can occupy, like any relay, moreover, two positions according to whether it opens or closes an electrical circuit 19 comprising two conductors 20 and 21, respectively connected to terminals 22 and 23 of this relay, this circuit comprising in series the resistances of the heating elements of the cooking appliance (not shown), connected in this circuit according to any appropriate configuration.

The relay 16 is of a conventional structure and in particular is such that it can close while ensuring the electrical continuity of the circuit 19 between the terminals 22 and 23, the closing of the relay being advantageously identified by the lighting of an indicator light. 24 disposed as close as possible to the face 18 of the strip 7, so that it can be located from the outside, in particular by the user having before the eyes the opposite face 15 of this strip.

According to the invention, the magnetic relay 16 is closed when the operating button 9 is in a position where the small permanent magnet 11 which it supports and which, in the example of FIG. 2, is embedded in the inside this button in the vicinity of the surface 13 of the latter, intended to be applied against the face 15 of the strip 7, is brought as close as possible to this relay, as illustrated in the Figure, the index 9a of the button 9, advantageously constituted by a lateral projecting part coming from molding during the manufacture of the button, in this case being opposite a determined mark 25 affixed on the surface 15.

To implement the switch, the user need only grasp the button 9, if necessary by removing it from its housing 14, then approach it to that of the switches 8 provided in the strip 7 which it wishes to ensure. control to turn on the fireplace heating 3 corresponding.

For this purpose, the button 9 is applied against the strip at the right of the chosen switch, so that the stud 10 which belongs to this switch engages in the open cavity 12 of the button so as to ensure centering without preventing its free rotation, the surface 13 of the button sliding without friction on the face 15 of the strip 7 facing outwards. When the index 9a of the button is brought to the level of the mark 25, the permanent magnet 11 which is located substantially in the radial plane of the button containing this index is disposed as close as possible to the associated relay 16. In this position, the magnet 11 closes the relay and the circuit 19 where it is inserted, by putting the corresponding focus under an appropriate voltage; on the other hand, when the button rotates relative to the previous position, the magnet 11 shifting angularly with respect to the relay 16, the latter returns to the initial position, that is to say in that where it opens circuit 19, putting the fireplace off.

Of course, it goes without saying that, as shown in Figure 1, each switch does not include a relay of the previous type, but a plurality of such relays, advantageously distributed evenly around the axis materialized by the central stud 10, so that the rotation of the operating button 9 on the latter allows successive openings and closings of each of these relays as the button pivots on the stud, in the positions which correspond each time when the index 9a of this button is brought in front of the successive references 25 carried by the face 15 of the strip 7. In each of these positions, the associated relay 16 closes a circuit in the manner already said but whose structure, here without incidence, makes it possible to gradually vary the heat energy delivered by the heating element corresponding, according to an entirely banal arrangement in the general construction technique of cooking appliances.

Figures 3 and 4 illustrate another alternative embodiment. In these figures, reference numbers identical to those used in the previous figures have been used to designate the same members.

In this variant, we thus find the glass strip 7 with its two opposite faces, respectively 15 and 18, the face 15 facing outwards being arranged to receive one or more control buttons 9, each of these comprising a permanent magnet 11 embedded in the button, this magnet being provided to ensure the opening or closing of magnetic relays 16, mounted in a chassis 17 immobilized against the opposite face 18 of the strip 7. Each relay is thus capable of '' be successively open or closed depending on the orientation of the button and in particular the position of its index 9a in front of the marks 25 carried by the strip, the closing of each of the relays 16 of a given switch resulting in the illumination of an indicator light 24.

In this case, however, the pin 10 of each switch, ensuring the centering in rotation of the operating button 9 did not come from manufacture with the strip or the glass plate 7, but is part of an attached support plate 26 and glued against the face 15 of the strip by means of a thin layer 27 of an appropriate adhesive of the epoxy or other type of adhesive, placed against the strip during the manufacture of the device or possibly against the corresponding face of the plate 26, protected before use by a peelable protective film 26a (Figure 4).

In this case, the button 9 can be held in place against the plate 26 or, as in the variant according to Figure 2, be fully separable from it, the button being removable and capable of being stored in period of non-use in the housing 14, for example for security purposes to prevent unauthorized use of the device, for example by young children.

In the case where the button remains permanently fixed against the strip, the plate 26 glued to the latter may in particular include a lateral edge 28 folded towards the center of the button in the direction of the stud 10, so as to trap a peripheral flange 29 of the button formed in the vicinity of its surface 13, which is housed under the edge 28.

Where appropriate and whatever the variant envisaged, the operating button 9 can cooperate with a washer 30 (see in particular Figure 4), attached to or attached to the plate 26, this washer 30 comprising a series of notches 31 angularly spaced around of the stud 10, these notches being intended to receive a lug 32 forming a pawl, carried by the bottom 33 of the button 9, each notch corresponding to one of the marks 25 on the face 15 of the strip 7 and to a position where the permanent magnet 11 ensures the closure of one of the relays 16 in the manner already indicated. In this case, the pawl 32 is preferably arranged in the same radial plane as that, passing through the center of the stud 10, which contains the magnet 11 and the locating index 9a.

A switch is thus produced for controlling the electrical powering of heating elements for a cooking appliance which has the essential advantage of requiring no drilling of the strip or the glass table of this appliance, the influence of the magnetic field created by the permanent magnet carried by the operating button transmitted to through the glass thickness to relays which, depending on the position of the magnet, open or close on demand.

The proposed solution is particularly safe and effective; in addition, it has a limited cost price, radically avoiding the problems posed by making holes in a glass element and preserving the seal necessary for the passage of axes engaged in such holes, while respecting conversely, the aesthetics of a continuous glass wall.

Of course, if the invention has been described with reference to several preferred examples, it is clear that it is not limited exclusively to the latter but embraces all variants. In particular, an embodiment in which the operating button would no longer undergo an angular displacement by rotation around the centering stud but a different movement, for example ensuring an axial displacement of the permanent magnet carried by this button to bring it closer or closer to it. 'deviating from the glass strip and as a result of the magnetic relay carried by the chassis disposed on the other side of this strip, cannot depart from the scope of the invention but would only perform a similar function in a different form for a similar result. It would therefore be equally covered by the claims below.

In particular, the permanent magnet movable relative to the glass plate for controlling the immobilized relay against the opposite face thereof, could be embedded in an elastic membrane, for example made of an elastomer-silicone material, in the central part of the latter, this membrane being slightly curved and glued by its periphery against the surface of the plate, so that the magnet located in the center can be brought slightly closer to the plate and consequently to the relay to close it this, following a pressure exerted on this membrane. On the other hand, due to its own elasticity, it returns to its initial position as soon as the previous effort ceases, discarding the magnet of the relay and allowing it to open.

Such an arrangement can in particular be provided for controlling an on-off switch for the cooking plate, the rotary switch more specifically described in the preceding variants then ensuring, depending on the direction of its rotation, the increase or the reduction of the heating powers available on each hearth of the hob.

Likewise, this arrangement could be used to make each of the keys separately from a control keyboard, the contacts of the corresponding Reed relays being advantageously of the "fugitive" type, that is to say arranged so that a pulse controls their closing for a fixed period, their opening then being automatically carried out after a given period of time.

Claims (12)

1 - Switch for controlling the switching on or off of an electrical element, in particular a heating element, through a strip or glass plate not pierced by a domestic cooking appliance (1), to ensure the tilting of '' at least one relay (16) closing or opening an electrical circuit (19) containing this element, by means of a small permanent magnet (11), this relay being a magnetic relay mounted in a fixed frame (17) immobilized against the face (18) of the glass plate (7) located towards the interior of the apparatus, and the switch (8) comprising an operating button (9) pressing against the opposite face (15) of the directed plate outwards and accessible to the user of the device, characterized in that this button is able to be freely driven in rotation with respect to the plate around a stud (10) whose location on the face of it is determined to have the button near the mounted relay against the other face, and comprises, offset radially in a plane passing through the stud, the permanent magnet (11), so that, following the rotation of the button on the stud, the magnet is brought to the right of the relay by causing the automatic tilting and closing thereof, or else be deported with respect to this relay, the latter then automatically returning to the open state, the stud (10) ensuring the location of the operating button (9), around which the button is rotated, cooperating with an open imprint (12), hollowed out in the center of the latter in its surface (13) which is applied against the plate (7 ). 2 - Switch according to claim 1, characterized in that the magnetic relay (16) is a relay of the relay type "Reed". 3 - Switch according to any one of claims 1 to 2, characterized in that the face (15) of the glass plate (7) directed outwards comprises a plurality of marks (25), regularly distributed in the surface of the plate around the center of the stud (10) on which the operating button (9) pivots, to allow an appropriate location of the permanent magnet (11) carried by this button against the plate, each corresponding mark in the face opposite (18) of the plate, to the mounting of a separate magnetic relay (16), so that the rotation of the button around the stud causes the successive closing or opening of each of the relays associated with these pins. 4 - Switch according to claim 3, characterized in that each mark (25) provided in the face (15) directed towards the outside of the glass plate (7) is also associated, near the corresponding magnetic relay (16) , to a light indicator (24) mounted in the circuit (19) comprising this relay, so that the closing of the latter simultaneously causes the lighting of this indicator. 5 - Switch according to one of claims 3 or 4, characterized in that the operating button (9) has a positioning index (9a) provided in its lateral surface and extending in the radial plane containing the permanent magnet (11), this index materializing, opposite each mark (25) on the glass plate (7), the position of the magnet in line with the magnetic relay (16) associated with this mark. 6 - Switch according to any one of claims 1 to 5, characterized in that the stud (10) came from manufacturing with the glass plate (7) and protrudes into the face (15) thereof directed towards the exterior of the appliance. 7 - Switch according to claim 6, characterized in that the operating button (9) is removable and completely separate from the glass plate (7). 8 - Switch according to any one of claims 1 to 7, characterized in that the stud (10) around which is provided the rotation of the operating button (9) is attached against the face (15) directed outwards from the glass plate (7). 9 - Switch according to claim 8, characterized in that the stud (10) is constituted by a projecting element, formed in the center of a plate (26) glued against the glass plate (7) by means of an adhesive layer (27) of the epoxy adhesive type or the like. 10 - Switch according to claim 9, characterized in that the operating button is removable or is mounted against the plate (26) being made inseparable from the latter while remaining free to rotate vis-à-vis the stud. 11 - Switch according to claim 10, characterized in that the plate (26) has a folded peripheral edge (28) in the direction of the stud (10) and under which engages an external flange (29) provided on the operating button (9) in the vicinity of its surface (13) which is applied against the glass plate (7). 12 - Switch according to any one of claims 9 to 11, characterized in that the plate (26) comprises, arranged coaxially with the stud (10), a washer (30) integral or fixed against the plate and having notches (31 ) angularly spaced, these notches cooperating with a lug (32) forming a pawl carried by the button (9), so as to immobilize the latter in positions separate successive.

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