EP2257744A1

EP2257744A1 - Household cooking oven

Info

Publication number: EP2257744A1
Application number: EP09715115A
Authority: EP
Inventors: Riccardo Pelizzoli
Original assignee: Indesit Co SpA
Current assignee: Whirlpool EMEA SpA
Priority date: 2008-02-29
Filing date: 2009-02-09
Publication date: 2010-12-08
Anticipated expiration: 2029-02-09
Also published as: WO2009107016A1; EP2257744B1; ITTO20080151A1

Abstract

A household cooking oven comprises a door (4) and a muffle (8) having a plurality of muffle walls (9-13) which delimit a cooking chamber (14). The oven has light emitting means (LS1, LS2, LS3) for lighting the cooking chamber (14), mounted outside the cooking chamber (14). According to the invention, at least one of the muffle walls (9-13) is made, or mainly made, of a transparent or translucent material adapted to let through visible electromagnetic radiation generated by the light emitting means (LS1, LS2, LS3). In the preferred embodiment, the transparent or translucent material is a glass or crystalline material, such as ceramic glass, tempered crystal, tempered glass, crystal glass.

Description

"Household cooking oven"

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DESCRIPTION

Field of the invention The present invention refers to household cooking ovens and has been developed with particular reference to ovens of the type wherein the heat is transmitted to the food products being cooked by means of conduction, convection or radiation, or through combination of two or more of such methods of heat exchange. Background art Ovens of the type indicated above typically include a casing, associated to which is an enamelled metal muffle, delimiting a cooking chamber. Generally provided for in cooking chambers are sliding guides for removable shelves, such as grids and trays, suitable to hold containers bearing the food products being cooked. Articulated at the front part of the casing is a glass door, used to close the cooking chamber at the front part. Ovens of the indicated type are also provided with means for heating the food products placed in the cooking chamber, typically represented by metal electrical resistances or gas burners, mounted inside or outside the muffle. For example, mounted inside the cooking chamber can be an electrical resistance referred to as "grill-type", arranged in proximity to the upper wall of the muffle and used for some types of cooking operations, so as to heat the food products by means of radiation. An electrical resistance may be provided for, in the so-called ventilated ovens, even behind the rear wall of the muffle, or behind a shell fixed at the inner side of the rear wall of the muffle: this resistance, usually circular, is substantially mounted at the delivery part of a fan, and for such purpose a series of slots is provided for in the rear wall of the muffle and/or in the abovementioned shell, for the passage of the air forced by the fan. It is possible to improve the heating of the food products being cooked by means of convection through the fan and the respective resistance. An electrical resistance, or a gas burner, may be provided for below the lower wall of the muffle, in such a manner to heat the container of a food product arranged on such wall by means of conduction. Household ovens of the indicated type are also generally provided with means for lighting the inside of the cooking chamber. In traditional ovens the main body of the muffle is usually made of metal material and it is generally configured as a deep-drawn single piece, which defines the lateral, upper, lower and bottom walls of the cooking chamber. The means for lighting the cooking chamber are usually mounted outside the muffle. For this reason, at least one wall of the muffle must be provided with a through opening, mounted at which is a body made using transparent material, typically tempered glass adapted to resist high temperatures. Mounted at the transparent body, outside the cooking chamber, is the light source, typically represented by a lamp socket associated to the muffle or to the oven casing, with a respective incandescent lamp (see for example EP-A- 0755627).

High sealing must be guaranteed between the transparent body and the edge of the respective opening made in the wall of the muffle, so as to avoid loss of heat or leakage of fumes and vapours from the muffle. This need, particularly evident in the case of ovens provided wit the pyrolytic cleaning function, complicates manufacturing of the oven, even regarding the insulation of the muffle. Furthermore, in order to reduce the risk of loss of heat and leakage of fumes and vapours, the openings provided for mounting the light sources must preferably be small in size within the wall of the muffle, and hence the lighting quality inside the cooking chamber is generally poor. In some cases, openings with the respective transparent bodies and light sources are provided for in several walls of the muffle, but such an approach evidently increases drawbacks linked to the need of guaranteeing the required sealing against loss of heat as well as leakage of fumes and vapours.

In some solutions, a seat accommodating a light source directly facing the cooking chamber, closed at the front by a respective transparent body, is made in the walls of the muffle in question. The light source can be relatively extended height-wise and a reflector can be associated thereto, to improve diffusion of light (see for example DE-A- 10314543). This type of solution allows enhancing the lighting quality of the cooking chamber, but essentially reveals the same drawbacks indicated previously.

Ovens provided with a lighting system which includes a light source, arranged outside the muffle, and light guides configured to deliver and/or diffuse the light produced by the external source into the cooking chamber (see for example DE-A-4100605) have been proposed. However, even these solutions complicate the manufacturing of the oven and they are usually not efficient.

Another drawback of the household cooking ovens according to the prior art is linked to the mounting of heating means, regardless of whether they are arranged inside or outside the muffle. For example, the positioning of the heating elements implies the use of supports that require to be anchored to the muffle or to the oven casing, hence complicating the assembly of the product.

Lastly, it should be borne in mind that the muffle body of the ovens according to the prior art must be subjected to an enamelling process. Such process requires the use of a special plant having an extremely extended layout (for indicative purposes, in factories for manufacturing medium size cooking apparatus, an enamelling plant occupies about 50% of the entire available space). Furthermore, the enamelling process has the drawback of generating highly polluting organic waste substances, which must thus be disposed of with due care, and thus implying the consequent costs.

Summary of the invention

The general aim of the present invention is that of overcoming one or more of the drawbacks indicated in the foregoing regarding traditional household cooking ovens. This general aim is attained, according to the present invention, by a household cooking oven having the characteristics indicated in the attached claims, which form an integral part of the technical teaching provided herein with reference to the invention.

Brief description of the drawings

Further objects, characteristics and advantages of the invention will become apparent from the ensuing description and from the attached drawings purely provided by way of example and with non- limiting purposes, wherein:

- figure 1 is a schematic front view of a household cooking oven according to the invention, with the front door partially open,

- figure 2 is a perspective view of a muffle body of the oven of figure 1 ;

- figure 3 is an exploded view of a muffle of the oven of figure 1 , with some interior supports and an oven tray,

- figure 4 is an exploded view of some components of the muffle of figure 3, such components being represented only partially and in enlarged scale;

- figure 5 is a partial perspective and schematic view of a reduced part of the oven of figure 1. Description of preferred embodiments of the invention

In figure 1 , a household cooking oven according to the invention is indicated with 1 as a whole. The oven has a casing indicated with 2, including a front frame 3 at whose upper part some control and display means, which form a control panel indicated with 3a, are arranged. Hinged at the front part of the casing, in particular at a respective lower edge, is a door 4 having a metal frame 5 provided with a front handle 6 and with a window made up of two or more parallel glasses, one of which is indicated with 7. The oven comprises a muffle, indicated with 8 as a whole. As can be seen also in figure 2, the muffle has a rigid body 8a having two lateral walls 9 and 10, a lower wall 11, an upper wall 12 and a rear wall 13. The muffle 8 delimits a cooking chamber, indicated with 14 as a whole, which can be opened and closed at the front by means of the door 4. According to an important characteristic of the invention, at least one of the walls 9- 12 which form the bearing structure of the muffle 8 is made, or mainly made, with transparent or translucent material, adapted to let through visible electromagnetic radiation generated through light generator means arranged outside the muffle 8. In a particularly advantageous embodiment of the invention, the abovementioned transparent or translucent material is a glass or crystalline material, such as ceramic glass, tempered glass, tempered crystal, crystal glass.

Unless specified otherwise, the expression that at least one wall of the muffle "is made, or mainly made" using the abovementioned transparent or translucent material is intended to indicate that at least one of the walls 9-12 is entirely made using said material, or that a prevailing portion of the rigid structure of the wall is made using the abovementioned material, and again that the wall in question, or its prevailing portion, may include - apart from the transparent or translucent material - also a different material, such not to jeopardise the possibility that the visible light passes through the wall itself, from the external towards the internal of the muffle: as will be seen, such different material may be a material constituting some mechanical connection members described hereinafter. Furthermore, unless specified otherwise, the definition "glass or crystalline" shall be intended in its widest meaning, and thus not only linked to the chemical/physical structure of the material in question, but also to the fact that such material is essentially a glass industry product, just like the case of glass and crystal products.

In the currently preferred embodiment, all the muffle walls 9-13 are made using the transparent or translucent material. Furthermore, as will be seen hereinafter, variant embodiments in which at least one of the walls of the muffle - for example the rear wall 13 is made using different material, for example a metal material, are possible. Still in the currently preferred embodiment, the muffle body 8a is made up of a plurality of rigid parts distinct and connected to each other, including two or more components each defining at least one muffle wall or a substantial portion of a muffle wall, and where at least one of the abovementioned components is configured as a pane or sheet made using the transparent or translucent material. For such purpose, reference numbers 19, 20, 21, 22 and 23 in figure 3 indicate rigid components of the muffle, made using the abovementioned transparent or translucent material and substantially configured to form a non-enamelled pane. In the shown example, panes 19, 20 and 23 substantially define the walls 9, 10 and 13 of the muffle 8, respectively, and panes 21 and 22 substantially define the lower and upper walls of the muffle, respectively. Furthermore, in the example, panes 19, 20 and 23 are substantially flat, while panes 21 and 22 are shaped in such a manner to have curved lateral regions. In particular, panes 21 and 22 have a main intermediate portion, indicated with 11a and 12a, and two curved lateral regions, indicated with l ib and 12b; in the shown example each curved lateral region l ib and 12b includes a wall end portion which is substantially perpendicular to the laying plane of the intermediate region 11a, 12a of the same pane: This characteristic is for example clearly visible in figure 4, regarding component 22 and the related wall 12. Thus, in the illustrated example, besides defining the lower and upper walls 11 and 12 of the muffle 8 panes 21 and 22 also define a small end portion of the lateral walls 9 and 10. In the embodiment exemplified in the figures, the oven 1 is further provided with coupling means, used for connecting two different components of the muffle to each other. In particular, in figures 2 and 3, four connection bodies or sections, extended longitudinally according to the depth dimension of the muffle and which can be conveniently made of metal material, for example extruded aluminium, in a simple and inexpensive manner, are indicated with 24. The sections 24 are used for joining the edges of two panes to each other. In particular, as ca be seen in figure 2 and 3 :

- one section 24 is used for connecting the upper edge of the pane 19 to the left edge (referring to figure 3) of the pane 22;

- one section 24 is used for connecting the lower edge of the pane 9 to the left edge ofthe pane 21;

- one section 24 is used for connecting the right edge of the pane 21 to the lower edge of the pane 20; and

- one section 24 is used for connecting the upper edge of the pane 20 to the right edge of the pane 22. Each section 24 is operatively interposed between longitudinally extended edge portions of two different panes 19-22, as can be seen for example in figure 4, where section 24 is shown, used for joining the panes 19 and 22 to each other, the latter being shown only partially. For such purpose, each section 24 has a substantially H-shaped part, so as to define two seats or throats 25 substantially parallel and opposite, which - in the example - extend for the entire length of the section itself: as deducible from figure 4, these throats 25 are each intended to receive a respective edge portion of a pane (19 and 22, in figure 4).

At least one of the two longitudinal ends of the sections 24 is preferably provided with a seat for receiving a mechanical fixing member. In the example illustrated in figure 4, the section 24 has two of such seats, only one of which is shown and indicated with 26. This seat 26 is configured to form a threaded blind hole, intended to receive a screw 27. The screws 27, with the related holes 26, can be conveniently used for anchoring further components of the muffle 8, or for locally anchoring the muffle body 8a to the casing of the oven 1. For example, the screw 27 represented at the front end of the section 24 of figure 4 may be used for locally anchoring to the muffle body 8a a front flange or frame, indicated with 28 as a whole in figure 3, intended to be covered by the front element 3 of the casing 2. This frame 28, practically intended to provide a mouth of the muffle 8, or of the cooking chamber 14, is used for example for mounting a gasket, indicated with 29 in figures 1 and 5, designed to cooperate with the door 4. As can be seen, holes 28a are provided for in the frame 28, for allowing screwing of the screws 27 into the respective front holes 26 of the sections 24 (see figure 4), in such a manner to fix the flange 28 and the muffle body 8a to each other. The screw 27 represented at the rear end of the section 24 of figure 4 may be used for locally constraining the pane 23, defining the rear wall 13 of the muffle 8, to the rest of the structure. For such purpose, as can be seen in figure 3, the pane 23 is provided with through holes, some of which are indicated with 23 a, intended to receive the screws 27, whose threaded parts are screwed into the rear holes 26 of the sections 24 in such a manner to fix the pane 23 to the rest of the muffle structure. In the annular zone of adjacency between the pane 23 and the rear edges of the other panes 19-22, a sealing means - for example a line of silicone glue - adapted to ensure fixing and sealing, is applied outside the muffle. It should be observed that the fixing by means of screws 27 should be deemed as provided solely for exemplification purposes, in that there are other possible methods for securing the pane 23 against the rest of the muffle, even through means that do not require presence of holes on the pane itself: for example, peripheral metal sections can be used combined with a metal counter-flange, to keep the pane 23 in position, or a metal counter- flange arranged at the rear part against the pane 23, with ties extending between this counter- flange and the front flange 28 of figure 3. The holes 26 of the sections 24 (figure 4) can also be configured as through holes, to receive the respective ties that extend between the front part and the rear part of the muffle.

Referring to figure 5, it should be observed that the rear pane 13 may be substantially square- or rectangular-shaped, with a greater perimeter than that defined by the rear edges of the panes 9-12. Besides simplifying mounting operations, such characteristic possibly allows providing the muffle with the abovementioned sections and/or counter-flanges, for fixing the rear wall in position even in the absence of holes.

As mentioned, the edges of two contiguous panes are received in the throats 25 of the sections 24 and the sealed fixing is completed by applying a gasket or silicone glue in the outer of the muffle 8, at each throat 25. Furthermore, in the case shown in figure 4, a plurality of threaded transverse holes 30, configured as through holes in the external wall 24a of section 24, at the upper throat 25, are made in section 24. Similar holes 30, not shown, are also provided for in the part of the wall 24a which laterally delimits the lower throat 25. The holes 30 may receive screws, one of which is indicated with 30a, being of aid in ensuring that the position of the edges of the panes and/or possible gasket is maintained inside the throats 25. However, presence of these screws 30a is not required, in that the configuration of the throats 25, their extension and the presence of glue is already enough to ensure that the correct operative position of the panes that form the muffle and the relative sealing is maintained. In addition or alternatively, the screws 30a can be used for fixing, at the outer part of the muffle 8, functional complementary devices or elements of the oven 1 , such as for example resistances for heating the cooking chamber and/or light sources, structural parts, etc. Further, additionally or alternatively to the holes 30, one or more threaded holes, for example configured as blind holes, can be provided for in the full intermediate portion of the section 24, i.e. the same portion having the holes 26, in this case made starting from its internal side: these holes can be advantageously used, like in the case indicated above, per for anchoring possible oven fittings, such as resistances, thermostats, lamp sockets, etc by means of screws.

In an advantageous embodiment, the coupling means represented by the sections 24 are used for anchoring, preferably in a removable manner, lateral support elements for shelves or trays of the oven 1. An oven tray is for example represented in figure 2, where it is indicated in with 31 as a whole. As can be seen in figures 1 and 3, the oven 1 is provided with two lateral support elements, indicated with 32. As can be seem also in figure 5, in the example shown each support 32 is made up of a substantially grid-like structure, made for example using metal bars welded to each other, configured to define parallel guides 33, intended to slidingly receive a lateral edge of the oven tray 31 of figure 3 or a grid shelf, not shown. In the assembled condition (see figure 1) the two support elements 32 are arranged substantially parallel, inside the cooking chamber 14, in a position essentially adjacent and parallel to a respective lateral wall 9, 11 of the muffle 8. These support elements 32 are anchored, in the respective upper and lower end regions, to the sections 24 provided for on the related side of the muffle, as clearly seen for example in figure 5 regarding the wall 9. Furthermore, in the represented example - with the aim of anchoring the lateral support element 32 to the sections 24 - the latter are provided with at least one threaded hole, preferably a blind hole, into which a mechanical fixing and support member is fastened. In figure 4, the abovementioned hole is indicated with 34 and it is made starting from the internal wall 24b of the section 24, at the solid intermediate part of the section itself. The member used for anchoring the support element 32 to the section 24 includes a screw indicated with 35, having a head sufficiently wide to be easily held between the fingers by a user and screwed, when the removal of the supports 32 from the cooking chamber 14 is required, for example when the chamber and/or the supports need to be washed. At the upper and lower ends, the structure of the supports 32 is suitably configured in such a manner to cooperate with the screw members 35, in order to maintain the support itself in a vertical and firm position. Provided for in the example is a single hole 34, substantially in an intermediate zone of the section 24: obviously, several holes 34 can be provided for in the sections 24, same case applying to several screws 35, with the aim of securing the supports 32 in a removable manner in the cooking chamber 14.

In a particular embodiment of the invention, the oven heating means include at least one heating element which is at least partially obtained using material applied or deposited on one of the panes formed by the abovementioned transparent or translucent material, or at least one heating element applied by serigraphy onto such pane by means of a support that is adhered to the pane itself. This characteristic is exemplified in figure 2, where two electrical heating elements, each made using material deposited on a pane 9, 10 are indicated with 36.

The heating elements 36 may be made up of heating or resistance elements directly serigraphed onto the panes 9 and 10 (or, as mentioned, by a serigraphed heating element applied by means of a support that is adhered onto the pane in question), according to the art known in other sectors (see for example, patent documents US-A-4,777,351 and WO2003/105530, or the technical publication "Conductive Ink Heaters" by WJ. Thatcher, regarding conductive ink heaters available at the following web page: http://www.coates.com/electro/drcuits/news/connections/conductive.htm

In cases where heating elements are used, expedients - per se known to a man skilled in the art - are used to avoid the detachment of such elements from the panes 9 and 10, and also to avoid current dispersions along the panes 9 and 10, occurrence of such phenomena being more likely at high temperatures. In a possible variant, the heating elements 36 include, or are made up of, one or more layers or films of mica or mekanite, such material being used for making heating elements, according to a technique being known, per se, in other sectors.

According to another possible variant, the heating elements 36 include, or are made up of, a thin heating layer, whose constituent material is represented by a mixture of several materials, including at least one heat-sensitive ceramic powder, with a positive temperature coefficient. This mixture preferably includes other materials selected from among nickel, chromium and iron. The thin layer may be deposited on the panes by means of any known technique, for example through PVD (Phisycal Vapor Deposition) or CVD (Chemical Vapor Deposition) methods. For a more detailed description of a heating element of this type reference can be made to document US 2002/0076215 Al, whose teachings thereof are incorporated herein.

Regardless of the type of embodiment chosen (serigraphy, mekanite, thin layer of mixture of materials), suitable power conductors, not shown in the figures for the sake of simplicity, are connected to the two ends of the heating element or resistance. Obviously, elements 36, or further heating elements, may be provided for on other panes of the muffle, for example the upper pane 22 or the lower pane 21.

In any case, the oven heating means according to the invention may also be of the traditional type, preferably mounted outside the muffle, according to the known art or by using, in case of lateral positioning of such elements, the sections 24, as mentioned beforehand. Obviously even a gas burner may be provided for, mounted below the pane 21. It should be observed that a possible radiation heating element, such as grill resistance, may be arranged, according to the invention, also outside the cooking chamber 14. In particular, such resistance can be located above the upper wall 12, which - in this embodiment - is made using a material transparent to infrared radiation. The radiation heating element may also be represented by a halogen lamp.

As explained beforehand, the material used for making the panes 19-23 is preferably a glass or crystal, such as ceramic glass, tempered crystal, tempered glass, or crystal glass. Materials of this type are perfectly capable of withstanding temperatures usually reached during a household cooking process, and they are also capable of withstanding the temperatures reached during the pyrolytic cleaning step, an operation provided for in some types of household cooking ovens. In a possible embodiment, for example, the material used is ceramic glass of the type currently used for making the so-called "ceramic-glass" cooktops. These materials are perfectly adapted to withstand temperatures up to about 600°. Another possibility is that of using a tempered crystal of the type currently used in the doors of household ovens, which are equally capable of easily withstanding temperatures up to at least 460°.

Due to the fact that, according to the invention, at least one of the walls of the muffle is made, or mainly made, using transparent or translucent material adapted to let through visible electromagnetic radiation, one or more light sources can be mounted outside the muffle body 8a, without having to provide the latter with through openings, seats for lamp sockets, reflectors or light guide systems according to the prior art.

A light source intended to light the cooking chamber 14 can be arranged at the point deemed most convenient, outside the muffle, exploiting the characteristic given by the fact that the panes 9-13 let through the visible light, from outside towards inside the chamber 14. This characteristic evidently also allows arranging several light sources outside the muffle, at different points, without providing for the necessary openings according to the more traditional art, alongside the related problems concerning ensuring sealing against loss of heat, fumes and vapours. In any case, the fact that even only one wall of the cooking chamber- for the prevailing area thereof - can crossed by visible light generated outside the muffle allows obtaining a noticeable improvement of the lighting quality of the chamber 14.

Preferably, the glass or crystal employed for implementing the invention is translucent, in order to obtain a better visual effect. For such purpose, in the currently preferred embodiment, the material forming one or more of the panes 19-23 is opalescent, with light colour tone, preferably tending to white. Obviously, the panes 19-23 can also be made with colours different from white or different from each other. Opalescence or colour of the panes 19-23 is obtainable through methods known to the glass industry, by manipulating the material during the processing step (particularly by adding specific colouring substances or substances suitable to produce opalescence such as chlorides, phosphates, oxides to the glass paste). As mentioned, alongside ensuring the attainment of a good lighting quality, opalescence allows achieving a significant aesthetic effect, especially when several light sources arranged at different points are active.

The invention allows a considerable versatility, both in terms of positioning, and in terms of the type of useable light sources. Strictly for exemplification purpose, some possible positions of light sources for lighting the cooking chamber of the oven 1 according to the invention are represented in figure 1. In the shown example two light sources LS 1 are provided for in the upper part of the oven 1, outside the muffle 8, at the upper corner zones; additionally or alternatively, two sources LS2 are provided for at the two lateral walls 9 and 10, also outside the muffle; still in figure 1, LS3 indicates a further light source longitudinally extended in a transverse direction of the bottom wall 11 of the muffle 8. Obviously, a light source can also be provided above the wall 12, with such a source also possibly serving as a radiation heating element (a halogen lamp, for example). It should be observed that even a single lateral source, for example in the position of one of those indicated with LS2 and having a configuration extended length-wise of the type indicated with LS3 (for example a neon lamp), is already suitable to guarantee a very high lighting quality for the cooking chamber.

The light sources LSI, LS2, LS3 may be of any type suitable for the application, and include for example incandescent lamps and/or neon lamps (like for example the case of the source LS3 of figure 1). It should be observed that one or more light sources may also be applied or placed against directly on the external surface of the pane/s 19-23 in question. In this case, preferably, a transparent or translucent layer of thermally insulating material, for example consisting of or including silicon or silica gel, is provided for between the light generator means in strict sense (for example light emitting diodes or LEDs) and the related pane 19-23. In a particularly advantageous embodiment of the present invention, one or more of the light sources LSI, LS2, LS3 (preferably light sources LS2 arranged in proximity to the lateral walls 9 and 10) include a LED panel, or an OLED, or an electroluminescent sheet, all being devices known per se in the prior art (as a non-limiting example, the device described in patent application WO99/55121 may be used). Such embodiment allows obtaining a very diffused and homogeneous lighting inside the cooking chamber 14.

In order to further improve the lighting effects inside the cooking chamber 14, in a particularly advantageous embodiment of the invention, one or more of the oven trays used in the oven 1 are also forned to a prevailing extent by a transparent or translucent material, adapted to let through visible electromagnetic radiation. In the case of figure 3, the oven tray indicated with 31 for such purpose has a peripheral frame 31a, made for example of metal material, and a solid central part 31b which is made of a transparent material, for example ceramic glass or tempered crystal. As deducible, in this manner, the light generated outside the muffle 8 is not substantially hindered by the oven tray 31 in terms of diffusion inside the cooking chamber 14 thereof. In the embodiment exemplified in the figures, the oven 1 is a static type oven, but the invention is clearly applicable even in case of ventilated ovens. In such case, behind the rear wall 13 of the muffle 8, substantially in the zone indicated with 40 in figure 1, a fan will be provided for (with a possible annular resistance, of traditional type or deposited/serigraphed on the panel 23) and the wall itself shall be provided with suitable passages for the passage of air with respect to the cooking chamber 14. In a possible implementation, the rear wall 13 of the muffle 8 may be made using a traditional material, for example enamelled metal, and hence easily provided with slots and supports for fans and/or rear resistances. Also the bottom wall 11 can be made of a non-transparent or opaque material. It is also clear that, in the oven according to the invention, not all the walls of the muffle must be necessarily made using transparent or translucent material: as deducible, various combinations are possible in such sense (for example the upper and lower walls made of metal, or other opaque material, and lateral walls made of transparent or translucent material, or vice versa). It should also be pointed out that the walls 9-12 of the muffle may be defined by a single piece of transparent or translucent material, such as glass or crystal: though leading to some practical disadvantages in terms of production, storage and handling of the piece, this type of embodiment is technically feasible and thus falling within the scope of the present invention. Therefore, in case of such an embodiment, the muffle body 8a includes a first component defining the abovementioned walls 9-12, without requiring the sections 24, and a component that forms the rear wall 13 (made using the transparent or translucent material or, as mentioned above, made of metal). From the same point of view, one same pane made of transparent or translucent material may define three walls of the muffle (for example the two lateral walls 9, 10 and one of the lower wall 11 and the upper wall 12), the muffle then being completed with the other required panes. Analogously two substantially C-shaped panes can be provided for, couplable by means of two sections 24 in an intermediate zone of the lateral walls of the muffle, to form the walls 9-13 as a whole.

It should be pointed out that, in the preferred embodiment, the supports 32 and the oven trays 31 are configured and dimensioned such that the lateral edges of the trays themselves are at a given distance from the respective lateral walls 9 and 11. This characteristic allows improving air circulation within the chamber 14, without requiring providing for holes or passages in the oven walls, as it typically occurs in the ovens according to the prior art.

Characteristics and advantages of the present invention are clear from the outlined description. The fact that at least one wall of the muffle, or a main or substantial part thereof (for example more than half) is made of transparent or translucent crystal or glass allows greater flexibility in the positioning of the lighting elements and in their type, overcoming drawbacks linked to the need of having to suitably seal the openings of the muffle provided for according to the prior art. The transparent or translucent material further allows a better diffusion of light within the entire cooking chamber, noticeably increasing the visibility and aesthetic effect of the oven.

The advantageous embodiment according to which one or more heating elements are directly deposited or applied on the panes constituting the walls of the muffle allows simplifying overall oven mounting operations, eliminating the need for specific supports for heating elements of the traditional type. This also represents an advantage in terms oven compactness and assembly times.

Another advantage allowed by the invention is represented by the fact that, in cases where all the walls of the muffle are made using glass or crystalline material, it is no longer necessary to perform any enamelling operation for components of the muffle, and this allows obtaining considerable advantages in terms of occupation of factory spaces, eliminating the need for an enamelling plant. The panels intended to make the muffle can be supplied directly by a glass or crystals manufacturer. Furthermore, at the end of the operating life of the oven, the material forming the walls of the muffle is easily reusable.

Provision of coupling means 24 is advantageous in case of interventions for technical assistance, for example when replacement is required of a heating element 36 and/or a light source made on a wall of the muffle or arranged behind a wall of the muffle: as a matter of fact, due to the sections 24, it is possible to partially dismount only the wall in question of the muffle, slipping it off at the front or at the rear of the muffle body, along the throats 25, after removing the respective gasket and/or the related sealing silicone material, and/or loosening the screws 30 of figure 3, when provided for. Regarding this, it should be observed that the configuration of the muffle could be tilted by 90° with respect to the illustration provided in the figures, in such a manner that components 19 and 20 form the upper and lower walls of the muffle, while components 21 and 22 form the two lateral walls of the muffle. It is clear that the household cooking oven described herein for exemplification purposes can be subjected to numerous variants by a man skilled in the art without departing from the scopes of the invention as defined in the attached claims. The shape of the panes 19-23 and sections 24 illustrated in the figures shall be deemed strictly for exemplifying purposes. Regarding this, it shall be observed that all the panes could be flat and the sections 24 could be replaced by angular sections, having substantially L-shaped sections, defining two longitudinal seats or throats which receive respective edge portions of the two orthogonal panes that need to be connected to each other.

Claims

1. Household cooking oven comprising a door (4) and a muffle (8), the muffle (8) having a muffle body (8a) with a plurality of muffle walls (9-13) which delimit a cooking chamber (14) closable at the front thereof by means of a door (4), the oven (1) further comprising heating means and light emitting means (LSI, LS2, LS3) for lighting the cooking chamber (14), mounted outside the cooking chamber (14), characterised in that at least one of the muffle walls (9-13) is made, or mainly made, of transparent or translucent material adapted to let through visible electromagnetic radiation generated by light emitting means (LSI, LS2, LS3).

2. Oven according to claim 1, wherein the transparent or translucent material is a glass or crystalline material, such as ceramic glass, tempered glass, tempered crystal, or glass crystal.

3. Oven according to claim 1 or 2, wherein the muffle body (8a) is formed by a plurality of distinct components (19-23) connected to each other, among which two or more muffle components each defining at least one muffle wall (9-13) or a substantial portion of a muffle wall, at least one said muffle component (19-23) being configured as a pane formed by said transparent or translucent material.

4. Oven according to claim 3, wherein the muffle (8) comprises coupling means (24) for connecting two different muffle components (19, 21; 19, 22; 20, 21; 20, 22) to each other, the two muffle components defining each a respective muffle wall (9-12) or a substantial portion of a muffle wall.

5. Oven according to claim 4, wherein a further muffle component (23) substantially perpendicular to said two muffle components (19, 21; 19, 22; 20, 21; 20, 22) is secured to the coupling means (24), the further muffle component (23) defining a respective muffle wall (13) or a substantial portion of a muffle wall.

6. Oven according to claim 4 or 5, wherein the coupling means comprise a connection element (24) longitudinally extended according to the depth dimension of the muffle (8), the connection element being in particular made of metal.

7. Oven according to claim 6, wherein the connection element (24) is operatively interposed between longitudinally extended edge portions of the two muffle components

(19, 21 ; 19, 22; 20, 21; 20, 22) and has two seats (25), each seat (25) receiving a said edge portion of a respective muffle component (19, 21; 19, 22; 20, 21; 20, 22), the connection body having in particular a substantially H-shaped or L-shaped transverse section.

8. Oven according to claim 6, wherein the connection element (24) has an end configured to cooperate with a mechanical fixing member (27), such as a screw, used for locally securing the connection body (24) to one of a muffle component (23) which defines a rear wall of the muffle (13) and a front flange or frame of the muffle (28).

9. Oven according to claim 4, wherein a lateral support element (32) for oven shelves and/or trays (31) is anchored to the coupling means (24), particularly in a removable manner, the lateral support element (32) being positioned inside the cooking chamber (14).

10. Oven according to claim 9, wherein at least two of said lateral support elements (32) are provided, arranged substantially parallel, each lateral support element (32) being anchored to at least one said connection element (24) and including a structure having means (3) for guiding said shelves and/or trays (31), each structure being extended inside the cooking chamber in a position substantially adjacent and parallel to a respective lateral wall of the muffle (9, 11).

11. Oven according to at least one of claims 4 to 6, wherein anchored to the coupling means (24) are one or more members or functional devices of the oven (1) outside the cooking chamber (14), such as a heating element, a lighting element, a structural component.

12. Oven according to claim 1 or 2, further comprising one or more shelves and/or trays (31) held in a removable manner inside the cooking chamber (14), one said shelf or tray (31) being made at least partially (31b) made of transparent or translucent material susceptible to let through a visible electromagnetic radiation, particularly glass or crystalline material such as ceramic glass, tempered crystal, tempered glass, glass crystal.

13. Oven according to claim 3, wherein the heating means comprise a heating element (36) at least partially obtained using material applied or deposited on one said component configured as a pane made of said transparent or translucent material (19-23).

14. Oven according to claim 13, wherein said heating element (36) comprise at least one of a serigraphed resistance, a layer or film made of mica or mekanite, a layer or film made of a mixture of materials including a heat sensitive ceramic powder having a positive temperature coefficient.

15. Oven according to claim 3, wherein the heating means comprise a radiating element arranged outside the cooking chamber (14), at a muffle wall (12) defined by one said component configured as a pane made of said transparent or translucent material (19- 23).

16. Oven according to claim 3, wherein at least two muffle walls (9, 10, 13), particularly at least three muffle walls, are substantially flat and each defined by a respective muffle component (19, 20, 23), at least one of which is configured as a pane made of said transparent or translucent material.

17. Oven according to claim 3, wherein said muffle component (21, 22) defines at least one muffle wall (11, 12) having a substantially flat intermediate region (Ha, 12a) and two curved lateral regions (l ib, 12b), where in particular each curved lateral region (l ib, 12b) includes a wall portion which is substantially perpendicular to a laying plane of the intermediate region (Ha, 12a) and the muffle component (21, 22) is configured as a pane made of said transparent or translucent material.

18. Oven according to claim 3, wherein the muffle (8) includes at least one from among: - two muffle walls (9, 10; 11, 12) substantially parallel to each other and defined by respective muffle components (19, 20; 21, 22) configured as panes made of said transparent or translucent material;

- four walls (9-12) defined by respective muffle components (19-22) configured as panes made of said transparent or translucent material; - one rear muffle wall (13) defined by a respective muffle component (23) configured as a panel made of said transparent or translucent material;

- one muffle component defining at least two muffle walls, configured as a panel made of said transparent or translucent material.

19. Oven according to claim 1 or 2, wherein the transparent or translucent material is substantially opalescent.

20. Household cooking oven comprising a door (4) and a muffle (8), the muffle (8) having a body (8a) with a plurality of muffle walls (11-13) which delimit a cooking chamber (14) closable at the front thereof by means of the door (4), the oven (1) further comprising means for heating the cooking chamber (14), characterised in that one or more muffle walls (9-13) are made, or mainly made, of glass or crystalline material, such as glass ceramic, tempered crystal, tempered glass, crystal glass.

21. Oven according to claim 20, further comprising light emitting means (LSI, LS2, LS3) for lighting the cooking chamber (14), mounted outside the cooking chamber (14), wherein the glass or crystalline material is a transparent or translucent material susceptible to let through a visible electromagnetic radiation generated by the light emitting means (LSI, LS2, LS3).

22. Oven according to claim 20 or 21 and one or more of claims 3 to 19.