Patent Publication Number: US-9429328-B2

Title: Cooking appliance and method for operating a cooking appliance

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a cooking appliance having a cooking chamber, which is delimited by walls of a muffle and has a loading opening on the front face, said loading opening being delimited peripherally by a front edge of the muffle. The cooking appliance also comprises a lighting apparatus with at least one light source. The invention also relates to a method for operating a cooking appliance. 
     Cooking appliances, such as ovens, are known, which have different slide-in levels in the cooking chamber for baking sheets, racks and the like. Such food holders can then be inserted at the different slide-in levels and the food placed therein can be prepared. In this context cooking appliances are also known, in which said slide-in levels and the cooking chamber as a whole can be illuminated by a lighting apparatus. 
     An oven with a corresponding lighting apparatus for illuminating a cooking chamber is known from DE 10 2005 044 347 A1. In this the light sources, which are configured as light-emitting diodes, are disposed outside the cooking chamber. To this end they are integrated in a side wall of the muffle, with a separating wall being disposed for this purpose between the light source and the muffle chamber. Insulating material is also disposed between the separating wall and the light source. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the present invention is to create a cooking appliance and a method, with which the displaying and lighting up of components is more user-friendly and more comprehensive for a user, in order to achieve better perceptibility in a manner specific to the situation. 
     This object is achieved by a cooking appliance which has the features claimed by the invention and a method which has the features of the invention. 
     An inventive cooking appliance comprises a cooking chamber in which food can be prepared. The cooking chamber is delimited by walls of a muffle. The muffle has a loading opening on the front face. The loading opening is delimited peripherally by a front edge of the muffle. The cooking appliance also comprises a lighting apparatus with at least one first light source. The lighting apparatus comprises at least one first light source for lighting up the cooking chamber and/or for displaying information, which is activated in at least a first operating mode of the cooking appliance, and at least one second light source, which is activated in a second operating mode that is different from the first operating mode. 
     The at least one second light source is preferably only activated in the second operating mode. This allows the signaling effect to be perceived particularly easily and the resulting lighting up of a component to be particularly easily identified for a user. 
     The at least one second light source is preferably disposed directly adjacent to a first light source. This ensures a space-saving embodiment. It also allows different lighting scenarios to be performed as it were from one point, the user perceiving these intuitively and identifying them easily in the different operating modes. 
     A light cone of an activated second light source in the cooking chamber is preferably oriented, at least partially, particularly with its optical main axis, forward out of the cooking chamber and obliquely downward. This is particularly advantageous, if a component of the cooking appliance, which projects partially out of the cooking chamber and is thus positioned so that it protrudes forward, is to be lit up. Since conventional lights in a cooking appliance only illuminate the cooking chamber, it is thus possible, when a baking sheet or the like is partially pulled out, also to light up the region projecting out of the cooking chamber. 
     The second operating mode preferably comprises the opening of a door closing off the cooking chamber and/or an at least partial removal of the food holder from the cooking chamber or a pyrolysis operation. In particular the second operating mode is the opening of the door and/or the removal of a food holder from the cooking chamber. In particular the second light source can be activated automatically when the door opens and/or when the food holder is removed. This enhances the abovementioned advantages. 
     The automatic deactivation of the at least one first light source is preferably linked to the activation of the second light source. It can take place as soon as a second light source is activated. However provision can also be made for the deactivation of a first light source only to take place after the end of a specified time period, for example of several seconds, after activation of a second light source. 
     The first operating mode can be for example the running of a preparation program, such as baking or cooking. 
     If a number of first and a number of second light sources are present, the deactivation of a specific first light source can be a function of the activation of a specific second light source. This means that one first light source can remain activated and another first light source can be deactivated. In particular this can be a function of the slide-in level, at which a first light source is to be deactivated and a second light source is to be activated, so that for example other slide-in levels can continue to be lit up by an assigned first light source. 
     The cooking appliance in particular comprises a control unit, which is configured to control the activation and deactivation of the light sources. 
     The at least one second light source can be disposed in the muffle or even outside the muffle. 
     Provision is preferably made, when the cooking appliance is viewed from the front, for said first light source to be positioned outside the cooking chamber and to be disposed in front of the front edge of the muffle. This light source position is particularly exposed in a space-saving embodiment. In particular said position is also particularly non-critical compared with other positions in respect of thermal loading of the light source. Additional measures such as insulating materials or the like are not required here. In addition it can be positioned here in such a manner that it has particular protection from mechanical influences. In particular it enables a particularly appropriate presentation of information in such a manner that a user can see it easily and quickly in addition to the illumination of the cooking chamber. 
     Provision is particularly preferably made for the at least one light source to be disposed between the front edge of the muffle and, when the appliance is viewed from the front, to be disposed in front of the decorative strip of the cooking appliance disposed on the front edge. This is particularly advantageous, as it means that the space that is present anyway, between the front edge or front flange of the muffle and the decorative strip, is utilized correspondingly. A support disposed therein to accommodate the light source is in particular provided. This allows particularly mechanically stable positioning. 
     Provision can be made for the light source, when the appliance is viewed from the front, to be disposed in such a manner that it is concealed by the decorative strip. This results in an advantageous embodiment in that a manner of impact protection for the light source is ensured when the food holder is introduced. Damage can thus be avoided. 
     The support is preferably a metal part, which is configured in the manner of a strip or as a hollow profile. As a result the at least one light source can also be let into the support, with the result that it is disposed with even greater protection and in an improved manner in respect of space saving. The thermal impact on the light source can be reduced further as a result. 
     The light source is disposed in particular on a support connecting the front edge of the muffle and the decorative strip. In such an embodiment the support functions in the manner of a mechanical connecting element between said components and is thus configured to be multifunctional. In addition to accommodating the light source, it is also provided as a mechanical stabilizing and connecting part. 
     Provision can also be made for the support also to accommodate at least one reflector to reflect the light from the light source into the cooking chamber and/or into a door closing off the cooking chamber. This can further improve the light distribution and the optical information presentation. 
     It is particularly advantageous if the light source is disposed in such a manner that, when a door closing off the cooking chamber is in a closed state, it is disposed at the side of the door. This requires additional space in respect of the depth of the cooking appliance. In particular it ensures the opening and closing of the door without restriction and the directly adjacent light source is not adversely affected in respect of mechanical strain or wear as a result. 
     In particular when the cooking appliance is viewed from the front, the light source is preferably disposed relative to the closed door in such a manner that in the depthways direction of the door and thus in respect of its thickness the light source is disposed laterally adjacent to the door within the depthways dimensions of said door. Since in this context seals are also generally configured on the front muffle flange or front edge, sealing the cooking chamber when the door is closed, the light source is thus also configured in front of said seal in practical terms. Because a door of a cooking chamber is generally configured from a number of plates disposed one behind the other, made in particular of a glass material, this also provides thermal insulation from the outside. This specific positioning of the light source also allows corresponding thermal insulation to be achieved due to the construction of the door, which according to one advantageous embodiment is likewise configured from at least two glass door plates in the form of an inner door pane and an outer door pane. 
     Provision is preferably made for the light source to be covered by the depth of the door when the door is in the closed state and for illumination of the cooking chamber to be prevented. With such an embodiment provision is preferably made for the cooking chamber to have a further lighting apparatus, which is provided to illuminate the cooking chamber and in particular individual slide-in levels when the door is in the closed state. 
     However provision can advantageously be made for the door to have a light-reflecting surface and for the light from the light source to be able to be directed into the cooking chamber to illuminate it by way of the reflecting surface when the door is in the closed state. A particularly specified advantageous embodiment is achieved here, in which this specifically disposed light source can also be used to illuminate the cooking chamber even when the door is closed. 
     The reflecting surface is preferably a mirror disposed between an inner door pane and an outer door pane. 
     The lighting apparatus preferably comprises at least two light sources, which are disposed one below the other in such a manner that, when the door of the cooking appliance is open at least, they are configured respectively to illuminate and/or display an assigned cooking chamber level and therefore a slide-in level. In particular a light source, when viewed as it were in a vertical direction, is disposed in each instance at the height at which the slide-in level is also positioned at its height level. 
     Provision can advantageously be made for the first light source to be configured to generate light in a first spectral range visible to humans and the at least second light source to generate light in a second spectral range visible to humans that is different from the first. Such an embodiment allows individual slide-in levels to be illuminated in different colors in a simple manner that can be identified at anyl time by a user. When a user is further away from the cooking appliance, he/she can also identify easily and quickly at all times which slide-in level is illuminated and in some instances correspondingly in use. 
     A light source is preferably disposed in such a manner that, when the door is open, its light cone is directed at least partially forward and downward. The light cone is therefore also directed forward out of the cooking appliance in a defined and specific manner. Partially removed or partially inserted food holders can thus also be lit up completely. 
     When a food holder is projecting partially forward out of the cooking chamber, the light cone is preferably oriented to illuminate the top face of the projecting part of the food holder. 
     The at least one light source is preferably disposed in a movable manner and the light cone can be pivoted as a function of the opening of the door and/or the at least partial removal of the food holder from the cooking chamber. This can be detected by sensors and controlled by a control unit. This allows very precise lighting that is appropriate to requirements. 
     Provision can preferably also be made, in addition to a light source for lighting up the cooking chamber and/or for displaying information, for at least one further light source to be disposed adjacent to the first light source, the light cone of the further light source being directed at least partially forward and downward when the door is open and the further light source being able to be activated when the door is opened and/or when the food holder is removed from the cooking chamber. Therefore at least two light sources are configured adjacent to one another, so that they are disposed practically at one level. This can be achieved for example by means of an array of light-emitting diodes. When the baking sheet is pulled out for example, the further light source can be switched on and can also light up the partially removed baking sheet on the outside. 
     The light source is in particular a light-emitting diode. These are particularly intense and can be operated in an energy-efficient manner as well as being very compact and small. However since such light-emitting diodes are relatively heat-sensitive, an inventive arrangement or an advantageous embodiment is particularly suited to this type of light source. 
     With an inventive method for operating a cooking appliance having a cooking chamber, which is delimited by walls of a muffle and which has a loading opening on the front face, said loading opening being delimited peripherally by a front edge of the muffle, and having a lighting apparatus with at least one light source, the lighting apparatus is configured with at least one first light source for lighting up the cooking chamber ( 2 ) and/or for displaying information, which is activated in at least a first operating mode of the cooking appliance, and at least one second light source, which is activated in a second operating mode that is different from the first operating mode. 
     Advantageous embodiments of the inventive cooking appliance are to be considered to be advantageous embodiments of the method. 
     Further features of the invention will emerge from the claims, the figures and the description of the figures. The features and feature combinations cited above in the description and the features and feature combinations cited below in the description of the figures and/or simply shown in the figures can be used not only in the respectively cited combination but also in other combinations or alone, without departing from the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention are described in more detail below with reference to schematic drawings, in which: 
         FIG. 1  shows a schematic perspective view of an exemplary embodiment of an inventive cooking appliance; 
         FIG. 2  shows a perspective view of subcomponents of an exemplary embodiment of an inventive cooking appliance; 
         FIG. 3  shows a partial section through a cooking appliance when viewed from the front according to a first specific operating mode; and 
         FIG. 4  shows a top view of the view in  FIG. 1  with the door of the cooking appliance also closed. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION 
     Identical elements or elements of identical function are shown with the same reference characters in the figures. 
       FIG. 1  shows a simplified perspective view of a cooking appliance in the form of an oven  1 . The oven  1  comprises a cooking chamber  2 , into which food can be introduced for preparation purposes. The cooking chamber  2  is delimited by a muffle  3 , which comprises corresponding side walls  4  and  5 , a top  6 , a bottom  7  and a rear wall  8 . A loading opening  9  is configured on the front face and can be closed off by a door  10 . In the illustrated embodiment the door  10  is hinged at the bottom and can be pivoted about a horizontal axis. Provision can also be made for the door  10  to be hinged at the side and able to be pivoted about a vertical axis. 
     The oven  1  also comprises an operating facility  11 , which is disposed on the front face only by way of example. The operating facility  11  can have one or more operating elements and a display unit. The oven can also have cooking zones (not shown), on which food preparation containers such as pots and pans and the like can be positioned. 
     The oven  1  also comprises a lighting facility  12 , which is configured to illuminate the cooking chamber  2  and/or to display information for a user. 
       FIG. 2  shows a perspective view of some components of the oven  1 , a horizontal section also being configured in the x-z plane. 
     The door  10  is not shown in the diagram in  FIG. 2 . The muffle  3  has a front edge  13  or muffle flange on the front face and at the periphery to delimit the loading opening  9 . A peripheral seal  14  is configured on this front edge  13 . A support  14  and  15  is disposed respectively toward the front and therefore in the x-direction in front of the front edge  13  in a first vertical region  13   a  of the front edge  13  and in front adjoining a second vertical segment  13   b  of the front edge  13 . 
     A decorative strip  16  and  17  is disposed in turn as an extension in the x-direction in front of the supports  14  and  15 . 
     When the oven  1  is viewed from the front therefore, the decorative strip  16  is disposed directly in front of the support  14  and this is disposed in front of the vertical segment  13   a  of the front edge  14 . The same applies to the arrangement of the support  15  in respect of the decorative strip  17  and the vertical segment  13   b.    
     The support  14  is connected in particular to the segment  13   a  on the one side and to the decorative strip  16  on the other side. The same applies to the support  15  in respect of the connection to the decorative strip  17  and the segment  13   b.    
     Disposed in the support  14  are a number of first light sources  18   a ,  18   b  and  18   c . These are configured as light-emitting diodes. The light sources  18   a  to  18   c  are thus disposed outside the cooking chamber  2  and are thus positioned between the decorative strip  16  and the segment  13   a , extending the front face in front of the segment  13   a . Corresponding light sources are also disposed correspondingly in the support  15 . The light sources  18   a  to  18   c  are configured to illuminate the cooking chamber  2  and in particular to illuminate an assigned slide-in level in each instance and to display information. In particular they are positioned so that, when the oven  1  is viewed from the front, they are disposed in such a manner that they are concealed by the decorative strips  16  and  17 . 
     Each light source  18   a  to  18   d  also has at least one second light source  29   a  to  29   d  directly adjacent to it. However the light sources  29   a  to  29   d  can also be disposed within the muffle  3 . In particular the first light sources  18   a  to  18   d  are activated in a first operating mode and the second light sources  29   a  to  29   d  are activated in a different second operating mode. If the operating modes run simultaneously at least periodically, at least one first and at least one second light source  18   a  to  18   d  and  29   a  to  29   d  can also periodically be activated simultaneously. For example when a cooking program ends, at least one of the first light sources  18   a  to  18   d  in particular is activated. If the door  10  is then opened as the program ends and a food holder is partially removed from the cooking chamber  2 , the second light source  29   a  to  29   d  assigned to light up the food holder from above at this slide-in level is automatically activated. Provision can however also be made for the at least one first light source  18   a  to  18   d  to be deactivated when the door is opened. 
     In the exemplary embodiment the supports  14  and  15  are embodied as long profiles configured as hollow at least in parts. They are configured both to accommodate the light sources  18   a  to  18   c  and also as parts to accommodate reflectors. Thus for example the light from the light source  18   a  is configured by way of a reflector disposed in the support  14  in the direction of the cooking chamber  2  and in particular the slide-in level assigned to said light source  18   a  and provided for specific illumination. 
     The light cone for illuminating a specific slide-in level in the cooking chamber  2  is shown schematically by way of example for the light source  18   c . A further light cone of a light source opposite on the support  15  is similarly outlined. 
       FIG. 3  shows a front view of a partial section through the oven  1 . In this exemplary embodiment three food holders  19 ,  20  and  21  are introduced at different slide-in levels into the cooking chamber  2 .  FIG. 3  also shows the further fourth light source  18   d  on this side, which is configured to illuminate the top slide-in level. The food holder  19  is disposed at this top slide-in level. 
     Provision is made for the light sources  18   a  to  18   d  to be configured to generate specific light colors. In particular provision is made for example for at least one of the light sources  18   a  to  18   d  to be configured to generate light in a spectral range visible to humans, which is different from a spectral range of one or more of the other light sources  18   a  to  18   d . This allows the individual slide-in levels to be lit in different ways that are also visible to humans. 
     Provision can also be made according to the diagram in  FIG. 3  for the lighting apparatus  12  to be designed so that optical displays can also be produced in the supports  14  and  15  as information for the user. For example, according to the diagram in  FIG. 3 , a number can be displayed optically, indicating the number of the associated slide-in level. 
     The light sources  18   a  to  18   d  are thus disposed on the oven  1  in such a manner that they are positioned in the region in front of the oven cavity between the oven cavity flange and the front face of a decorative strip. 
     According to a first embodiment provision can be made for the cooking chamber  2  and the individual slide-in levels only to be able to be illuminated when the door  10  of the oven  1  is open. 
     However provision is in particular also made for corresponding illumination of the cooking chamber or the specific slide-in levels to be possible with said light sources  18   a  to  18   d  even when door  10  is closed. 
     See also  FIG. 4  for further explanation in this respect.  FIG. 4  shows a top view of the view in  FIG. 2  and thus a view in the x-z plane. The door  10  is also shown in the closed state. This diagram again shows the arrangement behind one another in the x-direction of the decorative strip  16  or  17 , the support  14  or  15  and the vertical segments  13   a  or  13   d  of the front edge  13 . 
     A reflector  22  is also shown by way of example in the support  14 . This serves to reflect the light from the light source  18   a  out of the support  14 . 
     When door  10 , which has a thickness d, is closed, the light source  18   a  and the door  10  are positioned in relation to one another in such a manner that the light source  18   a  is disposed at the side of the door  10  and, when viewed in the depthways direction and thus in the x-direction, between the depthways dimensions of the door  10 . This means that, when the door  10  is in the closed state, it extends with its thickness d both to the front and to the rear beyond the dimensions of the light source  18   a . The same applies to the arrangement of the other light sources  18   b  to  18   d  and the light sources in the support  15 . 
     The door  10  comprises at least one inner door pane (not shown in detail) and an outer door pane disposed at a distance therefrom. Further intermediate door panes can also be present. 
     Disposed in the door  10  adjacent to the light sources  18   a  to  18   d  is a first mirror  23 . This serves to reflect the light emitted from the light source  18   a  in the direction of the cooking chamber  2  and in particular to illuminate the third slide-in level. The same is achieved in respect of a lighting means disposed in the support  15  with a minor  24  disposed on the opposite side. 
     The light sources  18   a  to  18   d  are preferably covered by light-permeable elements, which are disposed in cutouts in the support  14  and the support  15 . These transparent covers are marked in  FIG. 2  and  FIG. 3  with reference characters  25 ,  26 ,  27  and  28 . 
       FIGS. 2 to 4  show embodiments, in which the light sources  18   a  to  18   d  shine into the cooking chamber  2 . Provision can also be made for example for the light source  18   a  to be disposed in a pivotable manner and/or for the reflector  22  to be disposed in a pivotable manner. This allows the orientation of the light cone of the light source  18   a  to be changed. Based on the diagram in  FIG. 4  provision can then also be made, when door  10  is open and food holder  20  is partially removed from the cooking chamber  2 , for the top face of the region of the food holder  20  projecting forward out of the cooking chamber  2  to be able to be lit. Its removal can be detected by a corresponding sensor system and the position of the light cone can be changed by activation by a control unit. 
     In a further embodiment provision can be made for a further at least one second light source  29   a  (not shown) to be disposed practically at the same height adjacent to the first light source  18   a . This further light source is only activated when the door  10  is opened and the food holder  20  is pulled out of the cooking chamber. It is then preferably disposed in a fixed position and the optical main axis of its light cone is permanently set, with the light cone then lighting up the region of the partially removed food holder  20  projecting forward beyond the cooking chamber  2 . 
     Corresponding embodiments are then also provided for the light sources  18   b  to  18   d.    
     REFERENCE CHARACTERS 
       1  Oven 
       2  Cooking chamber 
       3  Muffle 
       4 ,  5  Side walls 
       6  Top 
       7  Bottom 
       8  Rear wall 
       9  Loading opening 
       10  Door 
       11  Operating facility 
       12  Lighting facility 
       13  Front edge 
       13   a  First vertical segment 
       13   b  Second vertical segment 
       14 ,  15  Supports 
       16 ,  17  Decorative strips 
       18   a ,  18   b ,  18   c ,  18   d  Light sources 
       19 ,  20 ,  21  Food holders 
       22  Reflector 
       23 ,  24  Mirrors 
       25 ,  26 ,  27 ,  28  Transparent covers 
       29   a  to  29   d  Light sources