Abstract:
An oven muffle that has at least two wall elements adjoining each other, which delimit at least some regions of an interior space that is used as a cooking chamber. The wall elements are of a glass or a glass ceramic and the adjacent wall elements are oriented at an angle with respect to one another. In an oven muffle of this invention, along with ease of cleaning, a simple structural design is achieved if the wall elements are integrally joined to one another and constitute one formed part.

Description:
PRIORITY CLAIM 
     German Patent Reference 10 2008 025 907.1, filed 29 May 2008, the priority document corresponding to this invention, to which a foreign priority benefit is claimed under Title 35, United States Code, Section 119, and its entire teachings are incorporated, by reference, into this specification. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an oven muffle, in particular an oven muffle having at least two wall elements adjoining each other which delimit at least some regions of an interior space that can be used as a cooking chamber, in which the wall elements are composed of glass or glass ceramic and the adjacent wall elements are oriented at an angle to one another. 
     2. Discussion of Related Art 
     Electrically heated ovens for freestanding ranges or for installation in a kitchen unit are generally known. The oven is essentially composed of an enameled oven muffle, which is heated from above and below with tubular heating elements. On the front side, the oven muffle is closed by a framed glass door. Usually, the upper heating system is situated on the interior of the oven muffle and in high-end ovens, is also assisted by a second heating element that enables the oven to execute a grilling function. The lower heating element is attached to the outside of the muffle floor. In addition to these standard heating schemes for upper/lower heating and grilling mode, a recirculating air fan is frequently also incorporated into the back wall, which can also have a separate heating ring in order not only to recirculate air, but also to produce hot air. 
     Another known approach is to embody oven walls of glass or glass ceramic. The use of glass ceramic in ovens is known from Canadian Patent Reference CA 2,183,498, which discloses an oven composed of glass ceramic for better cleanability. German Patent Reference DE 35 27 957 C2 describes an oven muffle composed of glass ceramic that is detachably assembled and is heated by externally mounted radiant heating elements. The plates are inserted into a supporting or holding frame, which means that the resulting edges and joints, particularly in the lower corner regions of the oven muffle, can only be cleaned with great difficulty. In addition, it has a high degree of structural complexity. Taking this into account, German Patent Reference DE 35 27 958 C2 proposes an enameled sheet steel muffle, with window openings provided in the side walls, into which the glass or glass ceramic plates are inserted. In this case, the same problem arises. In addition to the fact that the joints and connections can only be cleaned with difficulty, a large portion of the muffle chamber is again composed of enameled sheet steel. 
     SUMMARY OF THE INVENTION 
     One object of this invention is to provide an oven muffle that is easy to clean and has a low level of structural complexity. 
     This object is attained because the wall elements are integrally joined to one another and constitute one formed part. According to this invention, the wall elements are oriented at an angle with respect to one another. This yields an easy-to-clean, closed contour in the transition region between the two wall elements, oriented toward the interior. The integral joining of the glass or glass ceramic wall elements produces a mechanical bond that has a sufficient static stability. It is possible to eliminate the use of a support frame in order to simplify the construction. 
     According to one embodiment of this invention, it is possible for the formed part to have three wall elements and for the wall elements to be arranged so that the formed part is embodied as essentially V-shaped or U-shaped. If the oven muffle is embodied so that the two wall elements embodied as side walls are bent from the wall element embodied as the floor or ceiling, from its sides adjacent to opposing wall elements, then all of the edge regions of the oven muffle in which soiling usually has an elevated tendency to collect are easy to clean. 
     In one alternative embodiment of this invention, the boundary edges oriented toward the front and/or back of the oven muffle, belonging to the wall elements that have been bent toward each other, transition into each other to form a flat sealing surface. This makes it easy to achieve a successful contact and sealing of the oven door at the front of the oven muffle. An additional wall element that delimits the rear surface of the interior can be placed in a sealed fashion against the back surface of the formed part. 
     It is also possible for at least one of the wall elements to form a flat sealing surface on its side oriented away from the other formed-on wall element. It is then possible for additional wall elements or also other formed parts to be attached in a simple, sealed fashion to the sides of the wall elements. 
     The functionality of the formed part can be improved even further if at least one of the wall elements has at least one functional element, such as a projection, a receptacle, and/or a recess, integrally formed into or onto it, which is formed into the inner surface of the wall element oriented toward the interior or which protrudes from the inner surface into the interior. 
     In this case, it is possible for an oven muffle to be embodied, for example, so that in the region of or near the front and/or rear side of the oven muffle, the functional element is formed into or onto the wall element that constitutes or forms the oven muffle floor and/or the wall elements that constitute or form the oven muffle side walls. The functional element can then be used as a barrier or dam to prevent grease from leaking out. 
     It is also possible for the functional elements to be in the form of receptacles formed into or onto at least one of the wall elements forming the oven muffle side walls. The functional elements here are then able to perform a supporting function. In one embodiment of the oven muffle, the two wall elements that constitute or form the oven muffle side walls have receptacles that constitute or form guides for baking sheets, extending in the direction of the depth of the oven muffle. The concept of simple cleanability is thus also taken into account. 
     The functional element can also be a grease-catching basin, in the form of a recess in the oven muffle floor. 
     According to one embodiment of this invention, it is also possible for the interior to be delimited by at least two formed parts. The formed parts can then be assembled to delimit at least some regions of the interior. This results in a stable construction because the formed parts, in a frame-like fashion, constitute or form the oven muffle floor, the two oven muffle side walls, and the oven muffle ceiling. 
     Alternatively or in addition, it is possible for the formed part to be attached to at least one plate-like wall element that delimits the interior and for the formed part and the at least one plate-like wall element, in frame-like fashion, to constitute or form the oven muffle floor, the two oven muffle side walls, and the oven muffle ceiling. 
     The two above-mentioned frame-like structures successfully achieve a stable fixing of the assembly in a simple fashion because the formed parts or the formed part and the plate-like wall element are clamped against each other by strap elements. In order to account for the different thermal expansion behavior of the strap and of the glass/glass ceramic, it is possible for the strap to be embodied as spring-elastic in at least some regions or for the strap to be equipped with a spring element. 
     If the oven muffle according to this invention is embodied so that a supporting piece is held in the region of or near the joint between two formed parts placed against each other or in the region of or near the joint between a formed part and a plate-like wall element, then the functionality can be increased with a low level of complexity. The supporting piece can then be used either internally or externally for attaching add-on pieces. It is possible for a supporting frame to be fastened on the interior, such as for baking sheets, roasting pans, and the like. On the outside, the supporting piece can be equipped, for example, with mounts for suspending the oven muffle in the range. 
     It is also possible for the strap element to be equipped with mounting elements. It is then possible, for example, to fasten heating elements to the strap. The mounting elements can also be used for suspending the oven muffle in the range. 
     The supporting piece can also have a lamp for illuminating the interior. In particular, a temperature-resistant lamp can be in the form of optical fibers that couple their light into the edge of the wall element, in the vicinity of or near the joint. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       This invention is explained in view of exemplary embodiments shown in the drawings, wherein: 
         FIG. 1  is a perspective view of a laminar blank composed of a glass or glass ceramic material; 
         FIG. 2  is a perspective view of a formed part produced from the blank according to  FIG. 1 ; 
         FIG. 3  is a perspective view of a laminar blank composed of a glass or glass ceramic material; 
         FIG. 4  is a perspective view of a formed part produced from the blank according to  FIG. 3 ; 
         FIG. 5  is a perspective view of a laminar blank composed of a glass or glass ceramic material; 
         FIG. 6  is a perspective view of a formed part produced from the blank according to  FIG. 5 ; 
         FIG. 7  is a perspective view of a laminar blank composed of a glass or glass ceramic material; 
         FIG. 8  is a perspective view of a formed part produced from the blank according to  FIG. 7 ; 
         FIG. 9  is a perspective view of a laminar blank composed of a glass or glass ceramic material; 
         FIG. 10  is a perspective view of a formed part produced from the blank according to  FIG. 9 ; 
         FIG. 11  is a front view of a formed part produced from the blank according to  FIG. 9 ; 
         FIG. 12  is a perspective view of a laminar blank composed of a glass or glass ceramic material; 
         FIG. 13  is a perspective view of a formed part produced from the blank according to  FIG. 12 ; 
         FIG. 14  is a perspective view of a formed part produced from the blank according to  FIG. 11 ; 
         FIG. 15  is a perspective view of an oven muffle component including two structurally identical U-shaped formed parts; 
         FIG. 16  is a detail view taken from  FIG. 15 ; 
         FIG. 17  is a perspective view of an oven muffle component including two structurally identical U-shaped formed parts; 
         FIG. 18  is a detail view taken from  FIG. 17 ; 
         FIG. 19  is a perspective view of an oven muffle component including two structurally identical U-shaped formed parts; 
         FIG. 20  is a detail view taken from  FIG. 19 ; 
         FIG. 21  is a perspective detail view of an oven muffle component including a U-shaped formed part and a plate-shaped wall element; 
         FIG. 22  is a detail view taken from  FIG. 21 ; 
         FIG. 23  is a perspective view of a section of a strap element; and 
         FIG. 24  shows a front view detail of an oven muffle viewed. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a laminar, rectangular blank  10 . 1  comprising or composed of glass or glass ceramic cut from a glass/glass ceramic band. The top surface of the blank  10 . 1  has a continuous projection  17  profiled into it, which is formed from the melt during the rolling of the glass band. In  FIG. 1 , bending lines  18 . 1  are indicated with dashed lines, extending in the width direction of the blank  10 . 1 . At these bending lines  18 . 1 , the blank  10 . 1  is shaped into the formed part  10  shown in  FIG. 2 . During this, two vertical side wall elements  11  are bent upward from a horizontal wall element  12  at the bending lines  18 . 1  to form a U-shape, with rounded bending edges  18 . The wall elements  11  extend parallel to each other and perpendicular to the wall element  12 . It is possible for the wall elements  11  to be set in a V-shape, at an angle of greater than 90° in relation to the wall element  12 . 
     As shown in  FIG. 2 , the projection  17  in the region of the front of the oven muffle forms a spill barrier in the oven, the wall element  12 , that prevents grease, for example, from leaking out. The inner surfaces  13  of the wall elements  11  and  12  transition into each other in a rounded fashion for a favorable cleanability in the coupling regions. The front and rear edges of the wall elements  11  and  12  transition into each other in a flush fashion, yielding flat sealing surfaces  19 . 1  and  19 . 3 . An oven door, not shown, and an additional wall element, not shown, can abut it in a sealed fashion from the front and rear, respectively. The free ends of the wall elements  11  form horizontal sealing surfaces  19 . 2 . 
       FIGS. 2 and 3  respectively show a blank  10 . 1  and a formed part  10  for an oven muffle, whose embodiments correspond to those of the blank  10 . 1  and the formed part  10  according to  FIGS. 1 and 2 . The only difference is the embodiment of a second projection  17  situated or positioned in the rear region of or near the oven muffle. Consequently, a spatially delimited catch-basin is formed between the two bottom projections  17  and the respective wall elements  11 . 
       FIGS. 5 and 6  show embodiments of this invention that essentially correspond to those in  FIGS. 1 and 2 . As shown in  FIG. 5 , the inner surface  13  of the blank regions that constitute or form the side wall elements  11  have an undulating profile integrated into them. This forms rail-shaped recesses  15  that extend in the direction of the depth of the oven muffle which corresponds to the width of the blank  10 . 1 . The recesses  15  here are delimited by the projections  16  of the undulating profile elements. The profiling is stamped into the melt during the rolling of the glass band. The recesses  15  of the two wall elements  11  are situated or positioned opposite each other so that baking sheets or guide rails can be slid into them. 
     By contrast with the embodiment according to  FIGS. 5 and 6 , the undulating profiling can be provided in both the inner surface  13  and the outer surface  14  of the wall elements  11 , thus imparting an undulating pattern to the side muffle wall, the wall element  11 , as a whole. The function of the resulting internal recesses  15  and projections  16  corresponds to those shown in  FIG. 6 , but the projections  16  according to  FIGS. 7 and 8  can be stamped with greater intensity. 
       FIGS. 9 through 11  show a formed part for an oven muffle in which the wall element  12  constituting the floor has a recess  20  for catching spills. Starting from a flat glass ceramic plate, as shown in  FIG. 9 , a basin  20 . 4  in the floor region is produced during the forming process or in a subsequent, separate deforming process. This basin-shaped recess can usually be produced solely by the action of gravity on the glass ceramic plate during reheating. 
       FIGS. 12 through 14  likewise show the embodiment of a bottom basin for catching spills. In this case, however, the bottom basin  20 . 4  is produced by a forced deformation of the glass blank, which is moved downward by pressure or vacuum. The advantage here is that it is possible to produce forms, the bending edges  20 . 1 ,  20 . 2 , and  20 . 3 , that are larger and more sharply stamped than in the manufacturing procedure demonstrated in  FIGS. 10 and 11 . 
       FIG. 15  shows a component for an oven muffle that comprises or is composed of two U-shaped formed parts  10  that are produced and embodied in accordance with  FIG. 2 , except for the projection  17 . The two formed parts  10  are structurally identical, thus requiring only one production die. The two formed parts  10  are placed against each other in the region of or near the sealing surfaces  19 . 2 , with the interposition of a Teflon™ or graphite strip serving as a sealing element  19 . 4 . This produces a circumferential frame in which the lateral wall elements  11  of the two formed parts  10  respectively constitute or form the oven muffle side walls and the wall elements  12  respectively constitute or form the oven muffle ceiling and oven muffle floor. 
     The frame-like component is held together by two strap elements  30  that are embodied in the form of clamping straps. The strap element  30  is embodied as a metal band that has angled pieces  31  pointing outward at its band ends. Tabs  31 . 1  are punched and bent out from the angled pieces  31 . The tabs  31 . 1  each have an opening  31 . 2 . The strap elements  30  are looped around the front and back regions of the frame and the band ends are aligned with each other. A Teflon™ or graphite strip provided to protect against scratching can be inserted between the strap element  30  and the formed parts  10 . 
     When attaching glass ceramic muffles to metal parts, it is inherently necessary to take into account the different thermal expansions of the two materials because the metal frame expands or, if the metal frame were to internally engage in the oven muffle or were to be affixed to the oven muffle, the glass ceramic muffle would then crack and break during heating. For this reason, the band ends of the strap element  30  are attached to a spring element  32 . The spring ends are suspended in a prestressed fashion in the openings  31 . 2  of the angled pieces  31 . This takes into account the different thermal expansion behaviors. The spring element  32  can also be situated or positioned in a location other than the one shown in  FIG. 16 . It is also possible for the two formed parts  10  to be integrally joined to each other, for example by soldering or welding. 
     The arrangement shown in  FIGS. 17 and 18  corresponds to the one shown in  FIGS. 14 and 15 , with supporting pieces  40  embodied in the form of profiled sections inserted in the region of or near the joints of the formed parts  10 . The supporting pieces  40  have a bridge piece  40 , which supports a widened shoulder  42 . On the inside, the bridge piece  40  has a holding section  44  formed onto it, which has two legs  45 . The legs  45  are spaced apart from and parallel to each other. End sections  46  protrude at right angles from the leg ends  45 , providing an undercut receptacle  43  extending in the depth direction. In this receptacle  43 , fastening means, such as racks, baking sheets, rollers, guide rails, and the like, can be held and affixed in the interior of the oven muffle. The shoulder  42  and the holding section  44  prevent the supporting piece  40  from being pulled out from the joint. Sealing elements  19 . 4  are inserted between the bridge piece  41  and each of the sealing surfaces  19 . 2 . 
     The embodiment shown in  FIGS. 19 and 20  differs from the one according to  FIGS. 17 and 18  in that the bridge piece  41  of the supporting piece  40  is embodied in the form of a hollow profile and accommodates lamps  47  embodied in the form of an LED chain for illuminating the cooking chamber. It is possible to embody a supporting piece  40  that does not have a receptacle  43  and only accommodates the lamps  47 . 
     In addition to the shell-shaped formed parts  10  shown in  FIGS. 15 through 20 , it is also possible for the side wall elements  11  of the U-shaped profile to be embodied as taller and for an essentially flat wall element  50  in the form of a glass ceramic plate to be placed onto it as a muffle ceiling. The connection and fastening are carried out in a fashion analogous to the options described in conjunction with  FIGS. 15 through 20 . 
     In order to secure the oven muffle inside the oven unit as a whole, this invention provides the strap element  30  with punched-out tabs  33 , as shown in  FIG. 23 . The punched-out tabs  33  can be flexibly connected to a range frame  60  by crimping, screwing, riveting, or welding. A sealing element  34  in the form of a peripheral woven tube can be clipped into the intermediate space between the range frame and the oven muffle. This is a known technique that is currently used in pyrolysis ovens. This type of connection takes into account the different expansion of glass ceramic and metal and assures that thermal expansion does not cause the oven muffle to break. 
     The sealing element  34  is secured by a clamp  35 . The clamp  35  is situated or positioned between the strap element  30  and the range frame  60 , as shown in  FIG. 24 .