A cooking oven, in particular a domestic cooking oven The present invention relates to a cooking oven, in particular a domestic cooking oven, according to the preamble of claim 1.

A cooking oven consists of an oven cavity including a cavity wall made of metal and enclosed by an insulating layer. For ex- ample, the cavity wall is enamelled. The cavity wall must be strong enough for supporting heating elements, grid holders and/or a fan cover of an air heater. During a cooking process the oven cavity stores a substantial part of the consumed energy as thermal energy. The thermal energy stored by the oven cavity may be up to 10 % of the consumed energy. The amount of the stored energy depends on the mass and specific heat capacity of the oven cavity and on the temperature inside said oven cavity.

FIG 5 illustrates a schematic sectional side view of an example of a conventional cooking oven 10. The cooking oven 10 comprises an oven cavity 12, wherein a front opening of said oven cavity 12 is openable and closable by an oven door 18. The oven cavity 12 is enclosed by a cavity wall 14. In turn, the cavity wall 14 is enclosed by an insulating layer 16. The oven cavity 12 is ar- ranged within an oven chassis 20. A fan 22 is arranged in a rear portion of the oven cavity 12. A fan motor 24 for driving the fan 22 is arranged behind the oven cavity 12. An exhaust fan 26 is arranged above the oven cavity 12. A foodstuff carrier 28 for supporting foodstuff 30 is inside the oven cavity 12. A top heating element 32 is arranged beneath a top side of the cavity wall 14. A bottom heating element 34 is arranged beneath a bot ^¬ tom top side of the cavity wall 14. A rear heating element 36 is arranged in front of a rear top side of the cavity wall 14. A fan cover 40 is arranged in the rear portion of the oven cavity 12 and covers the fan 22 and the rear heating element 36. The cavity wall 14 supports the foodstuff carrier 28, the heating elements 32, 34 and 36, the fan 22, the fan motor 24 and the fan cover 40. This requires a sufficient thickness and results in a large mass of said cavity wall 14. Usually, the cavity wall 14 is made of metal. The cavity wall 14 stores a big amount of thermal energy and increases the energy consumption. Further, the preheating of the oven cavity 12 is delayed by said large mass of the cavity wall 14.

Another aspect of the rigid cavity wall made of metal is that the cleaning of the inner surface of the cavity wall requires abrasive methods in order to remove dirt from said inner sur ^¬ face .

It is an object of the present invention to provide an oven cav ^¬ ity for a cooking oven, which allows reduced energy consumption of the cooking oven and an easy cleaning of a cavity wall. The object is achieved by the oven cavity according to claim 1.

According to the present invention the cavity wall comprises a section at which at least one of said cavity component is ar ^¬ ranged, wherein at least said section of the cavity wall has in- sufficient mechanical strength to bear said at least one cavity component, so that said section of the cavity wall cannot bear the cavity component, and wherein the cooking oven comprises a bearing structure that is arranged outside of the cavity wall, wherein said at least one cavity component that is arranged in- side the oven cavity at said section of the cavity wall having insufficient mechanical strength is connected or connectable to said bearing structure, and wherein said section of the cavity wall with insufficient mechanical strength comprises at least one hole for connecting said at least one cavity component that is arranged at said bearing structure.

The core of the present invention is the insufficient mechanical strength of the section of the cavity wall, so that said section of the cavity wall cannot bear the cavity component. The cavity wall with the insufficient mechanical strength reduces the mass of the oven cavity and allows an easy cleaning of said cavity wall. The cavity wall stores less heat, reduces the energy con- sumption and accelerates the heating-up of the oven cavity. The cavity wall contributes to the reduced mass of the oven cavity, the reduced energy consumption and the accelerated heating-up of the oven cavity. Preferably, at least said section of the cavity wall with insuf ^¬ ficient mechanical strength, in particular at least one lateral, bottom, top or rear cavity wall or all of said lateral, bottom, top or rear cavity walls of the oven cavity, comprises a foil or a woven or non-woven textile material comprising at least one predetermined material, such as an oven temperature-resistant polymer, in particular a temperature-resistant polymer withstanding the temperatures of a pyrolytic oven-cleaning, or a sheet metal foil, in particular wherein said sheet metal foil has a thickness smaller than 0.6 mm, preferably smaller than 0.5 mm.

In particular, the bearing structure has a mechanical strength that is adapted to bear said at least one cavity component es ^¬ sentially independent of said section of the cavity wall.

Further, a front opening of the oven cavity is openable and closable by an oven door. Moreover, the oven cavity may be at least partially enclosed on its outside by an insulating layer that is adapted to effec ^¬ tively reduce the loss of heat from the oven cavity via the cav ^¬ ity wall, in particular via said section of the cavity wall with insufficient mechanical strength, in particular via said foil, woven or non-woven textile material.

In this case, the insulating layer may include a structure with a plurality of the chambers. Said chambers may have at least one predetermined shape. Preferably, the insulating layer includes a honeycomb structure. In general, the chambers may have an arbi ^¬ trary shape.

For example, the chambers of the insulating layer are filled with loose insulating material, preferably with perlite or aero ^¬ gel. Alternatively or additionally, the chambers of the insulat ^¬ ing layer may be evacuated or charged with low pressure.

Furthermore, the insulating layer may be arranged in contact with at least a part of the outer surface of the cavity wall, in particular wherein the insulating layer supports at least a part of at least one of said section of the cavity wall having insuf ^¬ ficient mechanical strength, in particular wherein the insulat ^¬ ing layer supports at least a part of said foil, woven or non- woven textile material comprised in said section of the cavity wall .

In particular, the cavity wall is adapted to be exchangeable by a user, in particular wherein the cavity is adapted for manual exchangeable arrangement by a user within at least one of an outer oven chassis or said insulating layer, in particular wherein the cavity wall comprises at least one, preferably manu ^¬ ally, releasable fixation means corresponding to at least one fixation means of the outer oven chassis or the insulating layer .

In this case, the cavity wall may comprise a material capable of changing its shape during a heating step after the arrangement of the cavity wall by the user in order to adapt to a predeter ^¬ mined dimension and/or shape of the oven cavity, in particular wherein the cavity wall includes at least one pleated buffer space contractible by a shape memory alloy, when said cavity wall is heated up for the first time.

For example, the cavity wall is made of at least one of a woven or non-woven textile material and/or of an electrically heatable material, in particular wherein an electrically heatable mate- rial is interwoven with said woven textile material or inter ^¬ twined with said non-woven textile material.

Additionally, the foil, woven or non-woven textile material may be layered by at least one non-sticking coating, preferably on at least the inside of the oven cavity wall.

Moreover, said foil, woven or non-woven textile material may be layered by at least one low emissivity coating, for example tin oxide, preferably on at least the outside of the oven cavity wall.

In particular, the cooking oven comprises at least one oven chassis surrounding the cavity wall, preferably wherein the in ^¬ sulating layer is arranged between the oven chassis and the cav- ity wall.

Moreover, at least one of said bearing structure may be formed as part of at least one of the insulating layer and/or the oven chassis . Novel and inventive features of the present invention are set forth in the appended claims.

The present invention will be described in further detail with reference to the drawings, in which

FIG 1 illustrates a schematic sectional side view of a cooking oven according to a preferred embodiment of the present invention,

FIG 2 illustrates a schematic perspective view of a section of an insulating layer for the cooking oven according to the preferred embodiment of the present invention,

FIG 3 illustrates a schematic sectional side view of a part of the insulating layer for the cooking oven according to the preferred embodiment of the present invention in a cold state,

FIG 4 illustrates a schematic sectional side view of the part of the insulating layer for the cooking oven according to the preferred embodiment of the present invention in a heated state, and

FIG 5 illustrates a schematic sectional side view of an example of the cooking oven according to the prior art.

FIG 1 illustrates a schematic sectional side view of a cooking oven 10 according to a preferred embodiment of the present in ^¬ vention .

The cooking oven 10 comprises an oven cavity 12. A front opening of said oven cavity 12 is openable and closable by an oven door 18. The oven cavity 12 includes a cavity wall 14 and an insulat ^¬ ing layer 16. The inner space of the oven cavity 12 is enclosed by the cavity wall 14. In turn, the cavity wall 14 is enclosed by the insulating layer 16. The cavity wall 14 includes two lat- eral cavity walls 42, a bottom cavity wall 44, a top cavity wall 46 and a rear cavity wall 48. The oven cavity 12 is arranged within an oven chassis 20. A heating fan 22 is arranged in a rear portion of the oven cavity 12. The heating fan 22 is attached at a rear side of the cavity wall 14. A fan cover 40 is arranged in the rear portion of the oven cavity 12 and covers the fan 22. A fan motor 24 for driving the heating fan 22 is arranged behind the oven cavity 12, but within the oven chassis 20. An exhaust fan 26 is arranged above the oven cavity 12. A foodstuff carrier 28 for supporting foodstuff 30 is inside the oven cavity 12. A side grid 27 is arranged at the lateral cavity walls 42 for bearing the foodstuff carrier 28.

A top heating element 32 is arranged beneath a top side of the cavity wall 14. A bottom heating element 34 is arranged above a bottom top side of the cavity wall 14. A rear heating element 36 is arranged in front of a rear top side of the cavity wall 14. A cavity lamp 37 is arranged inside the oven cavity 12 at the cav ^¬ ity wall 14. In this example, the cavity lamp 37 is arranged be ^¬ neath the top cavity wall 46.

The cavity wall 14 does not have any supporting functions. The supporting functions are provided by the insulating layer 16 and/or by the oven chassis 20. In this example, the heating fan 22, the fan motor 24, the top heating element 32, the bottom top heating element 34, the rear heating element 36, the fan cover 40 and the foodstuff carrier 28 are supported by the oven chas ^¬ sis 20. The cavity wall 14 is supported by the insulating layer 16. Since the cavity wall 14 does not have any supporting functions, it can be made of thin material. The cavity wall 14 has an in ^¬ sufficient mechanical strength to bear the cavity components. Thin material stores little energy and allows low energy con- sumption of the cooking oven 10 and a fast preheating of the oven cavity 12. Furthermore, the thin material of the cavity wall 14 is flexible, which is advantageous for the inner surface of said cavity wall 14. The thin material of the cavity wall 14 can be bent in order to break the bond between dirt and the in- ner surface of said cavity wall 14, which allows an easy clean ^¬ ing of said inner surface of the cavity wall 14.

According to one embodiment, the cavity wall 14 is made of a foil. Alternatively, the cavity wall 14 may be made of a woven or non-woven textile material. Additionally, the thin material, e.g. said foil, for the cavity wall 14 may be layered by a non ^¬ stick coating. Said non-stick coating contributes to the easy cleaning of the inner surface of the cavity wall 14. For exam ^¬ ple, "SILIKOFTAL" is used as the non-stick coating. Further, a low emissivity coating, e.g. tin oxide, may be layered on the thin material. Moreover, a heatable coating may be layered on the thin material. A carbon nanotubes based heatable coating is described in DE 10 2007 018 540 Al . Furthermore, a polymer based heatable lacquer, e.g. Coating Suisse CS-DJF-3014, may be lay- ered on the thin material.

According to another embodiment, the cavity wall 14 may be made of the woven textile material, wherein a heatable material is interwoven with said woven material.

The foil or woven material for the cavity wall 14 may be con ^¬ nected to an external bearing structure 50, so that the oven cavity 12 has a structure like a tent. The bearing structure 50 is arranged outside of the oven cavity 12. The components 22, 27, 28, 32, 34, 36, 37 and 40 arranged inside the oven cavity 14 are connected to the bearing structure 50. In particular, said bearing structure 50 has a mechanical strength adapted to bear said at least one of the components 22, 27, 28, 32, 34, 36, 37 and 40 in the oven cavity 12. The fastening of the components

22, 27, 28, 32, 34, 36, 37 and 40 in the oven cavity 12 is inde ^¬ pendent of the mechanical strength of the cavity wall 14. A num ^¬ ber of holes 17 penetrate the cavity wall 14 and the insulating layer 16. The components 22, 27, 28, 32, 34, 36, 37 and 40 ar- ranged inside the oven cavity 14 are connected to the bearing structure 50 through said holes 17. The cavity wall 14 is ex ^¬ changeable by a user. The cavity wall 14 comprises, preferably manually, releasable fixation means 54 corresponding to fixation means 52 of the outer oven chassis 20 or the insulating layer 16.

In this example, the foil or the woven or non-woven material of the cavity wall 14 is removable by the user. Preferably, the foil includes a pleated flexible buffer space, which contracts and fixes the foil during the first heating-up. The heat con ^¬ traction may be realized by a one-way memory effect of shape memory alloys.

The supporting functions are provided by the insulating layer 16, by the heating elements 32, 34 and 36, by the oven chassis 20, by the bearing structure 50 and/or by another structure lo ^¬ cated outside the oven cavity 14.

FIG 2 illustrates a schematic perspective view of a section of an insulating layer 16 for the cooking oven 10 according to the preferred embodiment of the present invention. FIG 2 shows an example of the structure of the insulating layer 16 according to the present invention. According to the preferred embodiment, the insulating layer 16 has a structure with a plurality of chambers. In this example, the insulating layer 16 has a honeycomb structure. The insulat ^¬ ing layer 16 is formed by a plurality of chambers having hexago- nal base area. Said hexagonal base areas extend in the main plane of the insulating layer 16. In general, the insulating layer 16 has a structure with a plurality of chambers of an ar ^¬ bitrary shape. The chambers of the honeycomb structure of the insulating layer 16 may be filled with loose insulating material. For example, said loose insulating material is aerogel or perlite. The cham ^¬ bers of the honeycomb structure may be sealed. Alternatively or additionally, the chambers of the honeycomb structure may be evacuated or the pressure inside said chambers may be lowered, wherein the allowed pressure inside the chambers depends on the stability of the honeycomb structure. The evacuated or low-pres ^¬ sure chambers provide a high insulating effect and restrict an expansion of the chambers when the insulating layer 16 is heated up .

According to a first concept of the insulating layer 16 with the plurality of chambers, e.g. arranged in the honeycomb structure, the vacuum insulated chambers are filled with perlite. Standard heating elements, e.g. tubular heating elements, may be con ^¬ nected to the insulating layer 16 and used as a support for bearing a thin cavity foil without any coating. Said heating elements are supported by the oven chassis 20. The thin cavity foil forms the cavity wall 14 and may be easily exchanged when it is dirty. The exchangeable cavity foil comprises a pleated buffer space, which is contracted by a shape memory alloy when it is heated up the first time. The foodstuff carrier 28 is sup ^¬ ported by a holder arranged at the oven door 18. The fan motor 24 for a hot air function is also supported by the oven chassis 20.

According to a second concept the insulating layer 16 has the honeycomb structure with low-pressure insulated chambers filled with aerogel. A fixed flexible foil is arranged at the inner side of said insulating layer 16. The flexible foil is coated with a heatable lacquer and a coating, which is easy to clean. The fan motor 24 for the hot air function and the foodstuff carrier 28 are supported by the oven chassis 20.

FIG 3 illustrates a schematic sectional side view of a part of the insulating layer 16 for the cooking oven 10 according to the preferred embodiment of the present invention in a cold state.

The foil includes the pleated flexible buffer space mentioned above, which contracts during the first heating-up and fixes the foil. The zigzag pattern 38 represents the internal structure of the insulating layer 16 in the cold state. FIG 3 shows the foil with the pleated flexible buffer space before the first heating- up, wherein said foil is not yet contracted.

FIG 4 illustrates a schematic sectional side view of the part of the insulating layer 16 for the cooking oven 10 according to the preferred embodiment of the present invention in a heated state.

The zigzag pattern 38 represents the internal structure of the insulating layer 16 in the heated state. In FIG 4 the foil has contracted and fixes the foil after the first heating-up. The heat contraction may be realized by the one-way memory effect of shape memory alloys.

FIG 5 illustrates a schematic sectional side view of an example of the cooking oven 10 according to the prior art. The cooking oven 10 comprises the oven cavity 12, wherein the front opening of said oven cavity 12 is openable and closable by the oven door 18. The oven cavity 12 is enclosed by the cavity wall 14. In turn, the cavity wall 14 is enclosed by the insulating layer 16. The oven cavity 12 is arranged within an oven chassis 20. The fan 22 is arranged in the rear portion of the oven cavity 12. The fan motor 24 for driving the fan 22 is arranged behind the oven cavity 12. The exhaust fan 26 is arranged above the oven cavity 12. The foodstuff carrier 28 for supporting foodstuff 30 is inside the oven cavity 12. The top heating element 32 is ar ^¬ ranged beneath a top side of the cavity wall 14. The bottom heating element 34 is arranged beneath a bottom top side of the cavity wall 14. The rear heating element 36 is arranged in front of a rear top side of the cavity wall 14. The fan cover 40 is arranged in the rear portion of the oven cavity 12 and covers the fan 22 and the rear heating element 36.

The cavity wall 14 supports the foodstuff carrier 28, the heat ^¬ ing elements 32, 34 and 36, the fan 22, the fan motor 24 and the fan cover 40. This requires a sufficient thickness and results in a large mass of said cavity wall 14. Usually, the cavity wall 14 is made of metal. Thus, the cavity wall 14 stores a lot of thermal energy and increases the energy consumption. Further, the preheating of the oven cavity 12 is delayed by said large mass of the cavity wall 14. Moreover, the rigid cavity wall 14 made of metal causes that the cleaning of the inner surface of the cavity wall requires abrasive methods in order to remove dirt from said inner surface. These problems mentioned above are overcome by the oven cavity 12 according to the present invention. The present invention reduces the mass of the oven cavity 12 and allows an easy cleaning of the cavity wall 14. The cavity wall 14 is exchangeable. The cavity wall 14 is flexible and allows breaking away dirt from its surface. The cavity wall 14 of the present invention re ^¬ quires less material, reduces the energy consumption of the cooking oven 10 and accelerates the heating-up of the oven cav ^¬ ity 12.

Although an illustrative embodiment of the present invention has been described herein with reference to the accompanying drawings, it is to be understood that the present invention is not limited to that precise embodiment, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the in ^¬ vention. All such changes and modifications are intended to be included within the scope of the invention as defined by the ap ^¬ pended claims.

List of reference numerals

10 cooking oven

12 oven cavity

14 cavity wall

15 section of the cavity wall

16 insulating layer

17 hole

18 oven door

20 oven chassis

22 heating fan

24 fan motor

26 exhaust fan

27 side grid

28 foodstuff carrier

30 foodstuff

32 top heating element

34 bottom heating element

36 rear heating element

37 oven cavity lamp

38 zigzag pattern

40 fan cover

42 lateral cavity wall

44 bottom cavity wall

46 top cavity wall

48 rear cavity wall

50 bearing structure

52 fixation means

54 corresponding fixation means