Rail pull-out device for a microwave oven with an electrically insulating end cap on one side of the rail, and microwave oven

Description

[0001] One aspect of the invention relates to a rail extension device for a microwave oven. The rail extension device comprises a first elongated rail. The rail extension device also comprises a second elongated rail. The two rails are connected to each other and are displaceable relative to each other in the direction of their longitudinal axis. The two rails are made, at least partially, of an electrically conductive material. Another aspect of the invention relates to a microwave oven with such a rail extension device.

[0002] Rail-mounted extension devices with several rails that can be moved relative to each other are known in a variety of designs. They can be inserted into a cooking chamber and typically serve to hold the food carrier. Due to their sliding motion in the depth direction of the cooking appliance, the food carrier can be pulled out and pushed back into the cooking chamber, thus improving accessibility. Such rail-mounted extension devices are usually arranged laterally either directly on the vertical side walls of a muffle that defines the cooking chamber of the appliance, or they can also be arranged on additional support units, such as a support frame constructed of rods. Such a support frame can itself be attached to a wall of the muffle in a way that allows for non-destructive removal.

[0003] Since conventional ovens are typically used in temperature ranges and under mechanical stress where alternative, non-conductive runner system materials such as plastic are no longer functional, and other materials are comparatively more expensive, metal is a common material for such runners. For example, this could be steel or stainless steel.

[0004] Such rail extension devices are perfectly suitable for cooking appliances that do not have a microwave function.

[0005] However, microwave ovens work differently. Electromagnetic radiation in the form of microwaves induces an electric charge in electrically conductive components, creating a potential difference between several electrically conductive components that are insulated from each other. This instantaneous potential can vary between different components due to different influencing factors. If the components are stably connected by a conductive path, this potential is dissipated by the flow of current. If the components are electrically insulated, an excessively large potential difference, and thus an excessively strong electric field, can lead to electrical discharges, such as sparking.

[0006] To avoid these electrical discharges, a stable electrically conductive connection or stable electrical insulation should be sought between metallic parts.

[0007] Electrical discharges between parts can also lead to malfunctions of components or user dissatisfaction. In particular, the visual appearance of such a cooking appliance can be affected, for example, by discoloration of the materials at the point of sparking. The acoustic perception of such a spark can also unsettle a user, increasing doubt about the functionality of the cooking appliance. Furthermore, the movement characteristics of the rail extension mechanism can be impaired by localized welding, deformation, or material displacement caused by such a spark. Penetration of protective layers, such as enamel coatings, or changes in the material properties or surface finish of the rail can also lead to subsequent corrosion.Furthermore, since the positioning of the at least two rails of the rail extension device, which are movable relative to each other, is usually done manually by a user, such a potentially undefined positioning can lead to a position that is not suitable for microwave use, which can also lead to the disadvantages mentioned above.

[0008] A pull-out system suitable for microwave ovens is known, for example, from DE 10 2013 214 852 A1, DE 10 2013 214 853 A1, or DE 10 2013 214 854 A1. In these systems, a minimum distance between the metallic components is achieved using one or more spacers. A distance between the electrically conductive rails is maintained by means of the intermediate running elements or rollers, which are made of a non-conductive material. Further prior art information can be found in documents WO 2019 / 179956 A1 and DE 10 2008 009175 A1.

[0009] It should be noted that the above-mentioned problems can also occur if the door of the microwave oven is located close to a rail extension device, especially when the door is closed.

[0010] The object of the present invention is to provide a rail extension device suitable for a microwave cooking appliance, in particular enabling improved prevention of sparking between the rail extension device and a door of the microwave cooking appliance.

[0011] This problem is solved by a rail extension device and a microwave cooking appliance according to the independent claim.

[0012] One aspect of the invention relates to a rail extension device for a microwave oven. A rail extension device suitable for use with a microwave oven is thus provided. This means, in particular, that when the microwave oven is in operation and, for example, food is being cooked with microwaves, such sparking between electrically conductive components of the rail extension device on the one hand and the microwave oven on the other is effectively prevented. The rail extension device has a first, elongated rail. The rail extension device has at least one separate second, elongated rail. The at least two elongated rails are connected to each other, in particular directly connected to each other. The two rails are arranged to be displaceable relative to each other in the direction of their longitudinal axes.Both rails are made, at least in part, of an electrically conductive material. At least one rail has an electrically insulating end at its front end (viewed along its longitudinal axis), which, when the rail extension device is installed as intended in the cooking chamber of a microwave oven, faces the door of the microwave oven.

[0013] This electrically insulating end piece thus forms a front end component of a rail of the extension mechanism, in particular of the entire extension mechanism. This effectively electrically isolates the front end of the extension mechanism, which faces the door of the microwave oven, from the door. Particularly when the door is closed during the intended installation of the extension mechanism in the oven cavity, resulting in a relatively small gap between the front end of the extension mechanism and the inside of the door, this design of the extension mechanism effectively prevents sparking between the front end of the extension mechanism and the door of the microwave oven. The electrically insulating end piece is a separate component from the rail.

[0014] In particular, this can also protect the door from being scratched by a rail when closing the door, if the door touches the rail extension device which is not yet fully inserted when closing.

[0015] The end element is made of a material that, with regard to the life cycle of the microwave cooking appliance, including chemical and / or thermal cleaning (pyrolysis), does not crumble, splinter and / or is not damaged with loss of function when the rail extension device is removed during a free fall.

[0016] The end element also allows for electrical insulation to a baffle wall of the microwave oven and / or electrical insulation to the door from both sides.

[0017] In particular, the electrically insulating termination element also provides electrical insulation between the rails. This allows such an element to achieve a dual function of electrical insulation: both external and internal.

[0018] In one embodiment, the electrically insulating end element, viewed along the longitudinal axis of the rails, is the component of the rail extension device that projects furthest forward. This end element is thus positioned in a correspondingly exposed position and therefore has the smallest distance to the door of the microwave oven when the rail extension device is arranged in the cooking chamber and, in particular, when the door is closed.

[0019] According to the invention, the electrically insulating end element is arranged on the second rail, which is a guide rail of the rail extension device. In the intended arrangement of the rail extension device, a guide rail is the rail that can be moved along the longitudinal axis relative to the other rail. The other rail is then usually referred to as the fixed rail. This means that, after installation, it is virtually stationary within the cooking chamber and does not move relative to the walls of the cooking chamber. The guide rail is the rail that, when the rails and thus also the rail extension device are retracted, projects further forward in the depth direction than the other rail. Therefore, this guide rail is the one whose front end extends further forward than the other rail when both rails are retracted.This supports the advantages mentioned above, because even in this collapsed state, the electrically insulating end element is the component of the rail extension device located furthest forward.

[0020] According to the invention, the electrically insulating termination element is made of ceramic. It is made entirely of ceramic. Such a material design is advantageous with regard to the electrical insulation effect. It is also advantageous with regard to mechanical stability and long-term functionality with respect to this electrical insulation effect.

[0021] According to the invention, the electrically insulating termination element is formed in one piece. In one embodiment, the second rail has a front plate at its front end. This front plate covers the rail from the front. In particular, the rail is completely covered from the front by this front plate. Thus, when viewing the rail from the front, only the surface of this front plate is visible.

[0022] The elongated rail body behind the rail is then concealed by this front panel when viewed from the front. In particular, the electrically insulating end cap is located on the front panel. The front panel is therefore a multifunctional component. In addition to covering the elongated rail body, it stabilizes the rail. Furthermore, it serves as an advantageous support component for this front-mounted end cap. The end cap can thus be attached to the rail simply yet with mechanical stability.

[0023] In a non-inventive embodiment, the electrically insulating termination element extends through a hole in the front panel. In particular, the electrically insulating termination element is arranged on both sides of the front panel. This makes it mechanically easy to mount and mechanically stable.

[0024] According to the invention, the second rail is open at its front end. The electrically insulating end element is inserted into a hollow area of ​​this rail at the front, along with a coupling element. This hollow area can then be used to position a sub-element of the end element. This also ensures a mechanically stable fastening of the end element. In such a configuration, the second rail may not have such a front plate. In this case, a direct mechanical support and coupling between the end element and the elongated rail body is provided. In particular, in this embodiment, the electrically insulating end element forms the complete frontal cover of this elongated rail body.

[0025] This differs from the design of a front panel. With a front panel, the end element can be smaller than the front panel itself. In this embodiment, when viewed from the front, the electrically insulating end element can also be smaller in area than the front of the elongated rail body. This larger dimensioning of the preferably present front panel allows the aforementioned advantages to be achieved.

[0026] In a design without such a front plate, it is advantageous if the end element completely covers the elongated rail body from the front. Therefore, appropriate sizing is advantageous in this respect.

[0027] According to the invention, the coupling element of this electrically insulating termination element has an upper coupling boss and / or a lower coupling boss. This allows for a mechanically stable positioning of the termination element within the hollow section of the elongated rail body. A direct mechanical connection and retention of the coupling element within the hollow section of the elongated rail body is thus particularly advantageous. In particular, at least one such coupling boss provides a positive-locking fastening of the electrically insulating termination element inside the rail.

[0028] In a non-inventive embodiment, the coupling part has a side wall with a snap-in receptacle for a spring-loaded snap element. This spring-loaded snap element can be arranged on the first rail. The snap element and the snap-in receptacle form an automatically releasable and re-snapable end-position locking device for the rail extension mechanism. This end-position locking device secures the retracted position of the rails. This prevents unwanted movement of the rails relative to each other in this retracted state. This also offers advantages with regard to preventing unwanted sparking during operation of the microwave oven.

[0029] In one embodiment, the coupling element may have a recess on one side wall. This recess or trough is designed to engage a coupling element located on the first rail. Such a design allows for further mechanical positioning of the coupling element within the elongated rail body. Particularly in conjunction with at least one of the coupling lugs mentioned above, this mechanical positioning can thus be achieved in at least two spatial directions.

[0030] The aforementioned side walls of the coupling element are, in particular, vertical side walls. The coupling bosses are formed, in particular, on a top and a bottom surface. The coupling element preferably has a cuboid shape. The aforementioned coupling bosses and / or recesses are then formed on the corresponding surface areas.

[0031] In one embodiment, the front end of the second rail has a cross-sectional area or a front surface. When viewed from the front, the electrically insulating end element is located entirely within this front surface. It may be provided that, when viewed from the front, this end element extends only to partially cover this front surface of the rail. In this case, the area of ​​this end element is smaller than the area of ​​the front of the elongated rail body. In an alternative embodiment, the front end of the rail has a front surface, and the electrically insulating end element completely covers this front surface when viewed from the front. In particular, it can have precisely this area of ​​the front surface. Complete coverage is then achieved, but no further projection is provided.

[0032] In a further embodiment, however, it can be provided that, when viewed from the front, the end element has a larger surface area than the front surface of the elongated rail body of the second rail and, moreover, completely covers the front surface of the elongated rail body. In another embodiment, the electrically insulating end element can be provided that it has an upward projection. This is to be understood as the rail extension device being arranged as intended. Thus, an upward projection is formed in the vertical direction of the rail extension device. This projection extends beyond the upper surface of the rail on which the electrically insulating end element is arranged. In particular, the projection forms a food carrier stop element.This means that when a cooking tray is stored on the separate rail extension device, this overhang forms a stop element. The cooking tray can be placed onto the rail extension device from above and rests specifically on the upper side of the rail that has the electrically insulating end element on its front. This is, in particular, the guide rail. This prevents the cooking tray from being unintentionally shifted relative to the depth of the rail extension device, and especially from being unintentionally pulled forward. This also prevents the cooking tray from tipping off the rail extension device.

[0033] This design gives the electrically insulating termination element multifunctionality. It thus has both electrical and mechanical functionality.

[0034] In one embodiment, the electrically insulating end element is fixedly mounted on the second rail. However, it can also be arranged to be movable relative to it. In particular, in a relatively movable arrangement, it can be axially spring-mounted on it. This allows for a certain damping effect. Especially when forces act on the rail, and particularly on the end element, these forces can be absorbed. This prevents undesirable damage to the end element. Unwanted high and abrupt force peaks acting on the end element can thus be prevented.

[0035] In one embodiment, the rail extension device has at least one electrically conductive contact element. Depending on their relative position, and particularly at least when retracted, the rails are electrically connected by means of this contact element. This is an alternative to an electrically insulating arrangement of the two rails relative to each other, especially when retracted. Thus, an electrically insulating arrangement of the two rails relative to each other is also possible when retracted.

[0036] In an electrically conductive connection, the electrically conductive connecting element is arranged on the second rail, on which the electrically insulating end element is located. In one embodiment, the electrically conductive contact element can be U-shaped. It can be arranged at the front end of the rail, where the electrically insulating end element is also located. The U-shape can face the opening of the second rail. This ensures that, when the two rails are pushed together, this U-shaped contact element makes contact with the second rail, specifically with both legs of the U, when the two rails are pushed together. This contact can then occur on the top and bottom of this second rail.In particular, overlapping and under-overlapping connections are possible, so that the respective U-shaped leg rests against the outer sides of this additional rail. In this context, the contacting element also acts as a clamp-like gripping component. Thus, when the rails are pushed together, especially when they are in the pushed-together state, the electrical connection between the two rails is automatically established by this electrically conductive contacting element.

[0037] Electrical insulation of the electrically conductive parts, as they have been described, ensures a minimum distance between the rail extension device, particularly its front end, and a closed microwave oven door. This spacer, or electrically insulating end element, can be positively or frictionally connected to one of the rails, especially the running rail, and can be positioned directly against it. For example, a clamping connection, an adhesive connection, a crimped connection, an embossed connection, an interlocking connection, a locking connection, a screw connection, a welding connection, a snap-fit ​​connection, or the like may be used.

[0038] In particular, the technical design of the mechanical connection method ensures that the electrically insulating termination element is fixed in position. This eliminates tolerances in the movement between the electrically insulating termination element and the rail. Unwanted rattling noises or similar issues are thus avoided when the rail is moved. Furthermore, an internal rail travel limiter can be implemented to create defined, insulating gaps. In this regard, a relative position adjustment of the electrically insulating termination element on the rail can also be incorporated, if necessary.

[0039] Combinations of the aforementioned mechanical fastening devices for the electrically insulating termination element may also be provided. A clamping connection or a counter-connection may also be used. In particular, a spring-loaded counter-connection may also be implemented. Such a spring may also be formed on a front cap of the rail. In one embodiment, this may also provide for the relatively movable mounting of the electrically insulating termination element on the rail. In a design of the electrically insulating termination element in which it is directly inserted into the interior of the elongated rail body and mechanically held therein, this termination element may also be mushroom-shaped. In this context, it may also serve as a front cap for the rail.An internal track limit, as already described above, can be achieved, for example, by an embossing in a rail in a running area on rollers or balls of the rail extension device, with which the two rails are mounted so that they can move relatively relative to each other.

[0040] A stable electrical connection between two electrically conductive parts of the rail extension device, particularly the rails that move relative to each other, can be achieved through a self-retracting mechanism, a spring connection, and / or a sliding contact. In particular, the contact area should be as large as possible to improve electrical conductivity. This prevents localized heating and / or sparking. Specifically, this large contact area should be designed so that even a slight gap between the conductive parts does not lead to such sparking.It can be provided that a spring resiliently connects the electrically insulating termination element to the corresponding rail, and furthermore, that this spring also provides an electrically conductive connection between the two rails when they are pushed together. In particular, a resilient connection between the two rails can also be achieved here by this element. Specifically, this can be the U-shaped contact element mentioned above.

[0041] In particular, a snap-fit ​​connection is also achieved here in the collapsed state. This allows for an alternative end-position locking device, either in addition to or instead of the aforementioned end-position locking device.

[0042] A rail extension device preferably also includes a ball bearing guide with balls that allow the rails to move relative to each other. These balls can be made of metal. Point contact between the moving rails can occur, potentially leading to accidental discharges or sparks during operation of the microwave oven. This can also cause undesirable discoloration at the affected areas. However, this discoloration is located inside the rails and is therefore neither visually nor functionally noticeable or problematic. A preload on the rail and the force of gravity ensure a permanent, electrically conductive contact between the rails and the balls.

[0043] The terms "top", "bottom", "front", "back", "horizontal", "vertical", "depth direction", "width direction", "height direction" indicate the positions and orientations given when the rail extension device or the device is used and arranged as intended.

[0044] Further features of the invention can be found in the claims, the figures and the description of the figures.

[0045] Exemplary embodiments of the invention are explained in more detail below with reference to schematic drawings. These show: Fig. 1 shows a schematic and perspective view of a household appliance according to one embodiment of the invention; Fig. 2 shows a schematic and perspective view of the cooking chamber of the household appliance according to Fig. 1Fig. 3 a perspective partial view of a rail of an embodiment of a rail extension device not according to the invention with an embodiment of an electrically insulating end element; Fig. 4 a partial view of a rail of an embodiment of a rail extension device not according to the invention with a spring bearing for an electrically insulating end element; Fig. 5 a perspective view of a partial area of ​​an embodiment of a rail extension device not according to the invention; Fig. 6 a perspective view of an embodiment of the electrically insulating end element according to the invention for positioning at a front end of a rail of a rail extension device; Fig. 7 a top view of an embodiment of a rail extension device in which an electrically insulating end element according to Fig. 6is arranged at a front end of a rail of the rail extension device; Fig. 8 a horizontal sectional view of the arrangement according to Fig. 8 ; and Fig. 9 a side view of the representation in Fig. 7 and Fig. 8 .

[0046] In the figures, identical or functionally equivalent elements are given the same reference symbols.

[0047] In Fig. 1 A schematic diagram shows a household appliance designed as cooking appliance 1 for preparing food. Cooking appliance 1 is specifically a microwave cooking appliance, for example, a standalone microwave oven or a combination appliance in the form of a conventional oven with a microwave generator. Microwave cooking appliance 1 may optionally also have a pyrolytic cleaning function.

[0048] The microwave oven 1 has a cooking chamber 2, which is bounded by a muffle 3. The muffle, as a household appliance component, has vertical side walls 4 and 5, as well as a bottom wall 6, a top wall 7, and a rear wall 8. The loading opening of the cooking chamber 2 can be closed at the front by a door 1a.

[0049] For example, recesses or holes 9, 10, 11, 12 can be formed on the inner side of the vertical side walls 4, 5; their number and position are shown only as examples. Furthermore, recesses are provided in the opposite vertical side wall 5 at the corresponding height and in the corresponding number. The recesses 9, 10, 11, 12 serve to receive a support element 13 (see Fig. 2 ), which can be designed, for example, as a frame or so-called hanging grid.

[0050] Referring to Fig. 2The support element 13 can, for example, be mounted on the associated side wall 4 in a way that allows for non-destructive removal. Alternatively, it is also possible to permanently attach the support element 13 to the side wall 4, for example by welding or the like. Fig. 2 The support part 13 is shown only as an example and may also have other geometric shapes.

[0051] The support element 13 has two vertical bars 14, 15 arranged parallel to each other and spaced apart from each other, which are connected to each other by a plurality of horizontally arranged bars 16 running perpendicular to the vertical bars 14, 15. The horizontal bars 16 are U-shaped.

[0052] Furthermore, in Fig. 2A schematic representation shows an embodiment of a rail extension device 17. The rail extension device 17 has a first rail 18. In this embodiment, the first rail 18 is a fixed rail. This means that when the rail extension device 17 is arranged as intended in the cooking chamber 2, it is fixedly mounted there, particularly on a side wall 4, 5. In this embodiment, the rail extension device 17 can be mounted directly on the optional support part 13. However, it is also possible for this rail 18 to be mounted directly on a side wall 4, 5 if the support part 13 is not present.

[0053] In the exemplary embodiment, the rail extension device 17 has a further rail 19. This is a second rail separate from the first rail 18. This further rail 19 is displaceable relative to the first rail 18 in the direction of a longitudinal axis A of the two elongated rails 18 and 19. This allows for displacement in the depth direction of the microwave oven 1. The depth direction is the horizontal, rearward-oriented direction.

[0054] The additional rail 19 is shown in its extended state as an example. Here, the additional rail 19 is referred to as the running rail.

[0055] However, it may be provided that the rail extension device 17 has a further, third rail. This can be another running rail.

[0056] The rail extension device 17, in particular the further rail 19, has an electrically insulating end element 21 at a front end 20 viewed in the depth direction. In particular, the two rails 18 and 19, in particular their elongated rail bodies 22 and 23, are made of an electrically conductive material. In particular, it is metal. In particular, it is steel or stainless steel. This electrically insulating end element 21 is a separate component from the elongated rail bodies 22 and 23. The rail extension device 17 is designed for its intended arrangement in the cooking chamber 2 such that its elongated arrangement is oriented in the depth direction. This means that the front end 20 faces a front loading opening of the cooking chamber 2 when the rails 18 and 19 are arranged in the retracted state. In this case, the rail extension device 17 is also completely arranged in the cooking chamber 2.The rail extension device 17 is designed for non-destructive attachment and removal from the microwave cooking appliance 1.

[0057] The microwave oven 1 also has door 1a, as shown in Fig. 1 The door 1a is movable and attached to a housing 1b of the microwave oven 1. This allows the cooking chamber 2 to be closed from the front by the door 1a.

[0058] The front end 20, and thus also the electrically insulating end element 21, faces the door 1a when it is closed. In particular, a correspondingly small distance is formed between them. Viewed in the depth direction, this electrically insulating end element 21 is the component of the rail extension device 17 that projects furthest forward. It therefore has the smallest distance to the door 1a. This creates electrical insulation between the rail extension device 17 and the door 1a, which is also positioned without contact when closed.

[0059] In Fig. 3A partial view of another rail 19 of a rail extension device 17 is shown in a perspective view. In this non-inventive embodiment, a front plate 24 of the rail 19 is arranged at a front end 20. This is in addition to the elongated rail body 23. This front plate 24 is preferably made of metal. This front plate 24 covers the elongated rail body 23 of the rail 19 from the front, preferably completely. In this embodiment, the electrically insulating end element 21 is arranged directly on this front plate 24. It extends through a hole 25 in the front plate 24. The electrically insulating end element 21 is thus arranged directly on both sides of this front plate 24 in the assembled state. Various mechanical fastening connections can be provided here. In this regard, connections can be provided as already mentioned above.Several combinations of connections can be provided to attach the electrically insulating termination element 21 to the front panel 24. A fixed attachment can be provided here. This means that the electrically insulating termination element 21, considered as a whole, is arranged on the front panel 24 without any possibility of movement.

[0060] In an alternative embodiment not according to the invention, the electrically insulating termination element 21, considered as a whole, can be arranged to be relatively movable on the rail 19, here in particular on the front plate 24. Such an elastic relative movement bearing can be achieved, for example, by a spring element 26, as described in Fig. 4As shown, this can be implemented. This allows the electrically insulating termination element 21 to move resiliently towards this front plate 24 in the direction of the longitudinal axis A. Such a resilient mounting of the electrically insulating termination element 21 on the rail 19 is also possible even if this front plate 24 is not present. In particular, a corresponding direct mounting on the elongated rail body 23 is then provided. Here, too, as already explained, a fixed mounting or a resilient mounting in the direction of the longitudinal axis A can be provided.

[0061] In the non-inventive embodiment in Fig. 3When viewed from the front, and thus viewed along the longitudinal axis A, the electrically insulating termination element 21 is smaller than a front surface or a front cross-section 23a of the elongated rail body 23. In the embodiment shown here, the electrically insulating termination element 21 is button-shaped.

[0062] However, other shapes and geometric sizes may also be provided.

[0063] In Fig. 5 A further embodiment of a rail extension device 17, not according to the invention, is shown in a perspective view. It can be seen here that, in this exemplary view, the electrically insulating end element 21 is arranged directly on a preferably present front plate 24.

[0064] In contrast to the previously described embodiments, in which the two rails 18 and 19 have no electrical connection to each other in any displacement position, here an electrical connection between the rails 18 and 19 can also be provided directly. In particular, this can be formed automatically in specific displacement positions of the rails 18 and 19 relative to each other. In particular, this can be provided, and especially only, when the rails 18 and 19 are pushed together. For this purpose, the rail extension device 17 has an electrically conductive contact element 27. This is formed here on the rail 19 on which the electrically insulating end element 21 is also formed. In particular, this electrically conductive contact element 27 is fixedly arranged at the front end 20 of this further rail 19.In the embodiment shown here, the electrically conductive contact element 27 is U-shaped. It has an upper leg 28 and a lower leg. This is viewed in the vertical direction of the rail extension device 17. This vertical direction is oriented perpendicular to the longitudinal axis A. As shown in the figure below. Fig. 5As can be seen in the shown, compressed state of rails 18 and 19, the upper leg of the U-shape 28 contacts a top surface 30 of the other rail 18. Furthermore, the lower leg of the U-shape 29 directly contacts a bottom surface 31 of this other rail 18. Thus, a clamp-like gripping action is provided by an electrically conductive contact element 27. In particular, this electrically conductive contact element 27 is also arranged directly on the front panel 24 and electrically connected to it. This design also provides a spring-loaded mounting for the electrically insulating termination element 21. The electrically conductive contact element 27 is therefore multifunctional.The electrically insulating termination element 21 extends through an opening or hole 32 in a base leg 33 of the U-shaped electrically conductive contact element 27. The electrically insulating termination element 21 is thus also arranged on both sides of this base leg 33. Such an electrically conductive contact element 27, particularly with this specific shape, can also be provided in a rail extension device 17 that does not have such a front plate 24. In that case, it can be attached to the rail 19 in a different manner.

[0065] In one embodiment, this electrically conductive contacting element 27 can also form an end-position locking device. This end-position locking device then axially secures the compressed state of the rails 18 and 19. For example, a snap connection can also be provided here. In this regard, at least one of the U-shaped legs 28 and 29 can be configured as follows: Fig. 5 The device may have a snap element not shown or visible, which, for example, snaps into a snap recess on the upper surface 30 and / or on the lower surface 31 when this collapsed state is reached. However, an inverse embodiment may also be provided, in which a snap recess is formed on one of the legs 28 or 29 and a raised snap element is formed on the upper surface 30 and / or on the lower surface 31.

[0066] In Fig. 6The figure is shown in a perspective view of an embodiment of an electrically insulating termination element 21 according to the invention. Here, for example, it is formed as a front cap for placing and directly attaching to the front end 20 of the rail 19. This element is particularly useful when no front plate 24 is present.

[0067] This electrically insulating termination element 21 is formed in one piece. Like the previously mentioned embodiments, it can be made of ceramic. The electrically insulating termination element 21 has a cover part 34. This cover part is dimensioned such that, in the installed state, it completely covers a cross-section 23a of the elongated rail body of the rail 19 from the front. Therefore, it is also dimensioned larger than the one shown in the Figs. 3 and 5The illustrated embodiment of the electrically insulating termination element 21 is particularly larger in this respect. Therefore, in the illustrated embodiment, it has in Fig. 6 The electrically insulating end element 21 has a projection 35. In its assembled final state, this projection extends upwards beyond the area of ​​the cross-section 23a at the front end 20 of the rail 19, when viewed vertically. This projection 35 also forms a food carrier stop element. It is thus integrated into the electrically insulating end element 21 and formed integrally with it. A food carrier, such as a baking tray, wire rack, or drip pan, which can be placed on the separate rail extension device 17 from above, cannot therefore be pulled forwards or over this rail extension device 17 in the depth direction.

[0068] This electrically insulating termination element 21 additionally comprises a coupling element 36. It is directly adjoining or integrally formed with the cover element 34 and extends horizontally rearward from it. This coupling element 36 is specifically designed as a cuboid base body. An upper coupling boss 38 is formed on a top surface 37. This coupling boss 38 extends, in particular, over the entire depth of the coupling element 36. Additionally or instead, a lower coupling boss 40 may be integrally formed on an opposite bottom surface 39. These coupling bosses 38 and / or 39 engage, in particular in a form-fitting manner, in corresponding grooves in the further rail 19, in particular the elongated rail body 23. This is shown in the top view in Fig. 7 The upper groove 41 is indicated. The upper coupling lug 38 engages in this groove, as shown in Fig. 7 can be seen.

[0069] Furthermore, this coupling part 36 has a first vertical side wall 42. A recess 43 is formed in this first side wall 42. This recess is designed for engagement of an engagement element 44 ( Fig. 8 ) provided. This engagement element 44 is integrally formed on the further rail 19, in particular the elongated rail body 23, or is formed inwards. This allows for further mechanical positioning of the electrically insulating end element 21 on this rail 19.

[0070] In one embodiment, it is provided that a snap-in receptacle 46 ( ) is provided on an opposite vertical side wall 45 of this coupling part 36. Fig. 8 ) is formed. This snap-in receptacle 46 is also a recess or a depression. This is for the snap-in engagement of a spring-loaded snap element 47 ( Fig. 7 and Fig. 8) provided. In this embodiment, the end-position locking of the pushed-together rails 19 and 18 can then be achieved by the spring-loaded snap element 47 snapping into this snap receptacle 46. The spring-loaded snap element 47 is here specifically attached to the rail 18. An axially acting end-position locking device is also formed by this spring-loaded snap element 47 and the snap receptacle 46.

[0071] Furthermore, a further rearward-projecting hump 49 is formed on a rear side 48 of this coupling part 36. This hump is designed to abut a stop 50 when the rails 18 and 19 are pushed together ( Fig. 7 and Fig. 8 ) provided at a front end of the further rail 18.

[0072] In Fig. 7As already explained above, a top view of a section of the rail extension device 17 is shown. The compressed state of rails 18 and 19 is depicted. The arrangement of the electrically insulating end element 21 is visible. Furthermore, the coupling part 36 is inserted into the interior of the elongated rail body 23 of rail 19.

[0073] In Fig. 8 In a horizontal section view, the design is shown according to Fig. 7 shown. The cutting plane is in a plane relative to the figure plane. Fig. 7 drawn in a parallel plane.

[0074] In this embodiment, it is also possible for the two rails 18 and 19 to be directly electrically contacted. However, it is also possible for these rails 18 and 19 not to be directly electrically contacted, but rather electrically insulated.

[0075] In Fig. 9is a side view of the design of the rail extension device 17 according to Fig. 7 and Fig. 8 The projection 35 of the electrically insulating end element 21, extending upwards in the vertical direction beyond a top surface 51 of the further rail 19 or the elongated rail body 23, is visible. Furthermore, the snapped-in state of the spring-loaded snap element 47 in the snap receptacle 46 is also visible. It is also evident that the lower coupling lug 40 is positively inserted into a lower groove 53 on a bottom surface 52 in the elongated rail body 23. Reference symbol list

[0076] 1 Microwave oven 1a Door 1b Housing 2 Cooking chamber 3 Muffle 4, 5 Side walls 6 Bottom wall 7 Top wall 8 Back wall 9, 10, 11, 12 Recesses 13 Support part 14, 15, 16 Rods 17 Rail extension device 18 First rail 19 Second rail 20 Front end 21 End element 22, 23 Rail body 23a Cross section 24 Front panel 25 Hole 26 Spring element 27 Contact element 28 Upper U-leg 29 Lower U-leg 30 Top 31 Bottom 32 Hole 33 Bottom leg 34 Cover part 35 Overhang 36 Coupling part 37 Top 38 Coupling hump 39 Bottom 40Coupling hump 41Upper groove 42First side wall 43Recess 44Engagement element 45Side wall 46Snap fitting 47Snap element 48Rear 49Hump 50Stop 51Top 52Bottom 53Lower groove ALongitudinal axis

Claims

1. A rail pull-out device (17) for a microwave cooking appliance (1), having a first elongated rail (18) and a second elongated rail (19) connected thereto, wherein the two rails (18, 19) are displaceable relative to one another in the direction of the longitudinal axes (A) thereof, wherein the two rails (18, 19) are made from an electrically conductive material, at least in some regions, wherein at least one rail (19) has an electrically insulating closing element (21) at a front end (20), which faces a door (1a) of the microwave cooking appliance (1) when the rail pull-out device (17) is installed as intended in a cooking compartment (2) of the microwave cooking appliance (1), and the second rail (19) is configured to be open at the front end (20), and the electrically insulating closing element (21) is introduced with a coupling part (36) into a hollow region of the second rail (19) on the front side, wherein the coupling part (36) has an upper coupling protrusion (38) and / or a lower coupling protrusion (40), a positive fastening of the electrically insulating closing element (21) being formed thereby in the hollow region of the second rail (19), characterized in that the electrically insulating closing element (21) is formed in one piece from ceramic.

2. The rail pull-out device (17) as claimed in claim 1, characterized in that the electrically insulating closing element (21) is the component of the rail pull-out device (17) which protrudes furthest to the front, when viewed in the direction of the longitudinal axis (A) of the rails (17, 18).

3. The rail pull-out device (17) as claimed in claim 1 or 2, characterized in that the electrically insulating closing element (21) is arranged on the rail (19) which is a running rail of the rail pull-out device (17) and which protrudes further to the front than the further rail (18) in the pushed-together state of the rails (18, 19).

4. The rail pull-out device (17) as claimed in one of the preceding claims, characterized in that the coupling part (36) has on a side wall (45) a snap-in receiver (46) for snapping in a resilient snap-in element (47) which is arranged on the first rail (18), wherein an end position securing device, which can be automatically released and snapped in again, is formed by the snap-in element (47) and the snap-in receiver (46), the pushed-together state of the rails (18, 19) being secured in position thereby, and / or the coupling part (36) has a recess (43) on a side wall (42) for the engagement of an engagement element (44) which is arranged on the first rail (18).

5. The rail pull-out device (17) as claimed in one of the preceding claims 1 to 4, characterized in that the front end (20) of the second rail (19) has a cross-sectional area (23a), wherein the electrically insulating closing element (21) entirely covers the cross-sectional area (23a) when viewed from the front side.

6. The rail pull-out device (17) as claimed in claim 5, characterized in that the electrically insulating closing element (21) has an upwardly protruding overhang (35) which protrudes over an upper face (51) of the second rail (19) on which the electrically insulating closing element (21) is arranged, so that a cooking product carrier stop element is formed by the overhang (35) for a cooking product carrier which can be placed on the second rail (19).

7. The rail pull-out device (17) as claimed in one of the preceding claims, characterized in that the electrically insulating closing element (21) is arranged in a fixed manner on the second rail (19) or is arranged on the second rail (19) so as to be movable relative thereto, in particular so as to be mounted in an axially resilient manner.

8. The rail pull-out device (17) as claimed in one of the preceding claims, characterized in that the rail pull-out device (17) has at least one electrically conductive contacting element (27), wherein the rails (18, 19) are connected in an electrically conductive manner, depending on their displacement position to one another, in particular at least in the pushed-together state, by means of the electrically conductive contacting element (27), in particular the electrically conductive contacting element (27) is arranged on the second rail (19) on which the electrically insulating closing element (21) is arranged, in particular the electrically conductive contacting element (27) is configured in a U-shaped manner and is arranged at the front end (20) of the second rail (19).

9. A microwave cooking appliance (1) having a housing (1b) in which a cooking compartment (2) is configured, and having a door (1a) which is movably arranged on the housing (1b) and closes the cooking compartment (2) on the front side, wherein the microwave cooking appliance (1) has at least one rail pull-out device (17), as claimed in one of the preceding claims, which is arranged in the cooking compartment (2) such that the electrically insulating closing element (21) faces the door (1a).