Title:
Cooking Appliance Mounted in an Elevated Manner
Kind Code:
A1


Abstract:
A cooking appliance which is mounted in an elevated manner and which comprises at least one muffle which defines a cooking area, whereby said muffle comprises an opening in the base thereof and which is surrounded by a muffle frame, a base door which is displaced by means of a drive device and which is used to close the muffle opening, at least one switch panel which is used to displace the base door in a directional manner. Said cooking appliance also comprises a memory unit which is used to memorise at least one target position of the base door, wherein the base door can be displaced in an automatic manner to the stored target position after the switch panel is actuated, until at least one target position is reached.



Inventors:
Bally, Ingo (Traunstein, DE)
Feldmann, Kerstin (Bretten, DE)
Fuchs, Wolfgang (Altenmarkt a.d. Alz, DE)
Keller, Martin (Traunreut, DE)
Kuttalek, Edmund (Grassau, DE)
Neuhauser, Maximilian (Chieming/Egerer, DE)
Roch, Klemens (Trostberg, DE)
Schnell, Wolfgang (Trostberg, DE)
Zschau, Günter (Traunwalchen, DE)
Application Number:
11/990530
Publication Date:
03/05/2009
Filing Date:
08/01/2006
Assignee:
BSH Bosch und Siemens Hausgeräte GmbH (München, DE)
Primary Class:
International Classes:
F24C15/02
View Patent Images:
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Primary Examiner:
NDUBIZU, CHUKA CLEMENT
Attorney, Agent or Firm:
BSH Home Appliances Corporation (NEW BERN, NC, US)
Claims:
1. 1-21. (canceled)

22. An elevated cooking appliance comprising: at least one muffle defining a cooking chamber, with the at least one muffle having a base side and a muffle opening formed on the base side; a base door for moving into and out of a covering relationship with the muffle opening; a drive device operatively associated with the base door, with the base door being movable by the drive device into and out of a covering relationship with the muffle opening; at least one displacement switch for selectively moving the base door in a selected direction; and a memory unit for storing at least one target position of the base door whereby upon storing a target position and actuation of the at least one displacement switch, the base door is automatically moved to a next selected target position present in the relevant displacement direction.

23. The elevated cooking appliance as set forth in claim 22 further including an actuation button; the at least one target position being stored by actuating the actuation button with the base door at the target position.

24. The elevated cooking appliance as set forth in claim 23 further including at least one optical and/or acoustic signaling device; the at least one optical and/or acoustic signaling device being activated when the actuation button has been actuated and a target position stored thereby.

25. The elevated cooking appliance as set forth in claim 22 further including a jamming protection device; the jamming-protection device being activated when a target position has been stored.

26. The elevated cooking appliance as set forth in claim 22 wherein the memory unit includes at least one volatile memory chip for storing the target position.

27. The elevated cooking appliance as set forth in claim 22 further including means for gently starting the movement of the base door and gently braking the base door when a target position has been stored.

28. The elevated cooking appliance as set forth in claim 22 whereby in the absence of a stored target position for a displacement direction, the base door can be displaced only by appropriately actuating at least one of the displacement switch panel continuously.

29. The elevated cooking appliance as claimed in claim 28 further including a second displacement switch panel whereby in the absence of a stored target position for a displacement direction, the base door can be displaced only by actuating both displacement switch panels continuously and simultaneously.

30. The elevated cooking appliance as set forth in claim 29 further including a housing; the displacement switch panels being attached to the front of the housing.

31. The elevated cooking appliance as set forth in claim 29 further including a housing; the displacement switch panels being attached to opposite sides of the housing.

32. The elevated cooking appliance as set forth in claim 28, further including means for gently starting the movement of the base door and for abruptly stopping the moving of the base door in the absence of a stored target position.

33. The elevated cooking appliance as set forth in claim 25 further including means for deactivating the jamming-protection device in the absence of a stored target position.

34. The elevated cooking appliance as set forth in claim 22 further including a power-failure buffer; means for re-initializing travel measuring of the base door at the zero position, wherein travel measuring of the displacement path is carried out incrementally; and wherein the drive device includes a motor shaft; at least one sensor for travel measuring of the displacement path of the base door, with the sensor located on the motor shaft of the drive device.

35. The elevated cooking appliance as set forth in claim 37 wherein the sensor is a Hall sensor.

36. The elevated cooking appliance as set forth in claim 22 further including a main switch; the base door being displaceable with the main switch deactivated.

37. The elevated cooking appliance as set forth in claim 22 wherein automatic displacement of the base door can be deactivated when the displacement switch panel has been actuated for longer than a predetermined actuating time.

38. The elevated cooking appliance as set forth in claim 34 wherein said predetermined actuating time is 0.4 seconds.

39. A method for operating an elevated cooking appliance having at least one muffle that delimits a cooking chamber, a base side, a muffle opening on the base side, a base door and a drive device with the base door being displaceable by the drive device for closing the muffle opening, at least one displacement switch panel for enabling the displacement of the base door direction-dependently, and a memory unit, comprising: storing at least one target position of the base door in the memory unit; actuating the at least one displacement switch panel; and automatically displacing the base door to the next target position present in the relevant displacement direction.

40. The method as set forth in claim 39 further including, in the absence of a stored target function for a direction, continuing to displace the base door in the relevant displacement direction only while at least one displacement switch panel is being actuated.

41. The method as set forth in claim 40 further including displacing the base door in the relevant displacement direction only while two (2) displacement switch panels are actuated simultaneously.

Description:

The present invention relates to a high-fitted cooking appliance having at least one muffle that delimits a cooking chamber and has on its base side a muffle opening, a base door that is displaceable by means of a drive device for closing the muffle opening, and at least one displacement switch panel for displacing the base door direction-dependently.

Known from, for example, U.S. Pat. No. 2,944,540, DE 102 28 140 A1, and DE 101 64 239 A1 are high-fitted cooking appliances in the case of which a base door is displaceable by means of a drive motor, with the base door being displaceable in the desired direction when a displacement button has been actuated.

It is disadvantageous that such an operating manner is inconvenient for the user, especially since the desired final position can frequently be reproduced only with difficulty if not corresponding to a resting position on a work plate or to a final position specified in the design.

The object of the present invention is therefore to provide a high-fitted cooking appliance that is simpler to operate and flexible in terms of adjusting and displacing its base door.

The present object is achieved by means of the cooking appliance having the features of claim 1 and of the method as claimed in claim 18.

A memory unit for storing at least one target position of the base door is provided for that purpose. If a target position requiring to be attained has been stored, then the base door will keep moving automatically once the displacement switch panel has been actuated accordingly until said (next) target position has been reached (automatic operation).

It will be advantageous if the at least one target position can be stored by actuating an actuating button, for example for 2 to 4 seconds, with the base door at the target position. An actuating or storing signal, for example an optical and/or acoustic signal, is then favorably fed out.

Since the at least one displacement button, which is not limited in type, shape, or arrangement, needs to be actuated only briefly during automatic operation, for increased operational safety it will be advantageous for a jamming-protection device to have been activated when a target position has been stored.

To ensure that the—then possibly incorrect or unsafe target position(s)—will have been cleared following a relocation or a structural alteration, the memory unit includes volatile memory chips, for example RAMs such as DRAMs, SRAMs, MRAMs etc., for storing the target position. However, so that not every fluctuation in the a.c. power supply will clear the target positions (also called displacement positions), a power-failure buffer is provided typically for bridging fluctuations or outages in said supply lasting up to a few seconds.

For quiet operation the base door can advantageously be started up gently and braked gently, favorably by means of a speed or load ramp, once a target position has been stored.

The base door can in the absence of a stored target position for a displacement direction preferably be displaced only by appropriately actuating at least one of the displacement switch panels continuously (manual operation). Said target position can be absent if, for example, either no target position has been stored for that displacement direction—for example only a target position for an open position has been stored, which in the closing direction can mean the absence of a target position that can be moved to—or the single or last target position for that displacement direction has already been reached and no further target position is available for a further displacement in the same displacement direction. Manual operation will also become active if the displacement switch panel is actuated for longer than a specific maximum actuating time for automatic operation, in particular 0.4 seconds. Manual operation will then take precedence over automatic operation even in the presence of a target position that can be moved to.

For increased operational safety, in the absence of a stored target position for a displacement direction it is advantageous for the base door to be displaceable only by appropriately actuating two displacement switch panels continuously and simultaneously, i.e. with both hands.

For convenient displacing it is advantageous for the displacement switch panels to be attached to the front of a permanently installable housing. They can, though, also be attached to, for example, opposite sides of the permanently installable housing or at other locations.

For increased operational safety it is also advantageous if during manual operation—i.e. when the base door will move only when the displacement switch panel has been actuated—the base door will, although starting by moving gently, stop abruptly, i.e. will halt, for example through short-circuiting of the drive motor, as soon as the relevant displacement panel has been released.

A jamming-protection device will advantageously have been deactivated during manual operation and activated during automatic operation.

The base door can advantageously be displaced, during manual and/or automatic operation, even when the main switch is off.

For moving more precisely to the target positions it is possible to initialize travel measuring at the zero position, meaning in the defined closed condition. It is also favorable for travel measuring of the displacement path to be carried out incrementally and also for travel measuring of the displacement path—and hence of the position—of the base door to be carried out by means of at least one sensor, in particular a Hall sensor, located on a motor shaft of the drive device.

There are two displacement switch panels for that purpose so that the base door can be displaced only when both displacement switch panels have been actuated in the same direction for displacing the base door. That two-handed operation will prevent jamming of a free hand.

At least one displacement switch panel preferably includes a separate displacement button for each displacement direction, thus typically in each case an opening switch “OPEN” and a closing switch “CLOSE”, for example pushbuttons. Thus both “OPEN” switches must have been actuated for displacing the base door in an opening direction and both “CLOSE” switches must have been actuated for displacing the base door in a closing direction.

The invention is described schematically in more detail below with the aid of the attached figures:

FIG. 1 is a perspective view of a high-fitted cooking appliance mounted on a wall and having a lowered base door;

FIG. 2 is a perspective view of the high-fitted cooking appliance having a closed base door;

FIG. 3 is a perspective view of a housing of the high-fitted cooking appliance without the base door;

FIG. 4 is a schematic side view, in cross-section along the line I-I shown in FIG. 1, of the high-fitted cooking appliance mounted on the wall and having a lowered base door;

FIG. 5 is a front view of a further embodiment variant of a high-fitted cooking appliance;

FIGS. 6 to 11 are graphs of displacement movements of a base door under different boundary conditions;

FIGS. 12 and 13 are force-time profile graphs for a base door.

FIG. 1 shows a high-fitted cooking appliance having a housing 1. The rear of the housing 1 is mounted in the manner of a hanging cabinet on a wall 2. Defined in the housing 1 is a cooking chamber 3 that can be checked via a viewing window 4 provided at the front in the housing 1. It can be seen in FIG. 4 that the cooking chamber 3 is delimited by a muffle 5 provided with a thermally insulating casing (not shown) and that the muffle 5 has a muffle opening 6 on its base. The muffle opening 6 can be closed by means of a base door 7. The base door 7 is shown lowered in FIG. 1, resting with its underside on a work plate 8 of an item of kitchen furniture. In order to close the cooking chamber 3 the base door 7 must be moved into the position shown in FIG. 2, which is termed the “zero position”. For moving the base door 7 the high-fitted cooking appliance has a drive device 9, 10. The drive device 9, 10 has a drive motor 9, indicated in FIGS. 1, 2, and 4 by means of dashed lines, which is located between the muffle 5 and an exterior wall of the housing 1. The drive motor 9 is located in the area of the rear of the housing 1 and, as shown in FIG. 1 or 4, is operatively connected to a pair of lifting elements 10 linked to the base door 7. According to the schematic side view shown in FIG. 4 each lifting element 10 is therein embodied as an L-shaped support whose vertical limb extends from the drive motor 9 on the housing side. For moving the base door 7 the drive motor 9 can be actuated with the aid of an operating panel 12 and a control circuit 13, which panel is according to FIGS. 1 and 2 located at the front on the base door 7. As shown in FIG. 4, the control circuit 13 is located behind the operating panel 12 inside the base door 7. The control circuit 13, consisting here of a plurality of spatially and functionally separate printed-circuit boards that communicate via a communication bus, constitutes a central control unit for operating the appliance and controls and/or regulates, for example, heating, displacing of the base door 3, implementing of user inputs, illuminating, jamming protection, clocking the heating elements 16, 17, 18, 22, and much more.

It can be seen from FIG. 1 that a top side of the base door 7 has a cooking area 15. Virtually the entire surface of the cooking area 15 is occupied by heating elements 16, 17, 18, indicated in FIG. 1 by dot-and-dash lining. The heating elements 16, 17 are in FIG. 1 two differently sized cooking-hob heating elements spaced apart, while the heating element 18 is a panel heating element provided between and almost enclosing the two cooking-hob heating elements 16, 17. For the user, the cooking-hob heating elements 16, 17 define associated cooking zones or cooking troughs; together with the panel heating element 18, the cooking-hob heating elements 16, 17 define a bottom-heat zone. The zones can be indicated by means of a suitable decorative design on the surface. The heating elements 16, 17, 18 can each be controlled via the control circuit 13.

In the exemplary embodiment shown the heating elements 16, 17, 18 are embodied as radiating heating elements covered by a glass ceramic plate 19. The glass ceramic plate 19 has approximately the same dimensions as the top side of the base door 7. The glass ceramic plate 19 is furthermore fitted with mounting openings (not shown) through which protrude bases for fixing securing parts 20 for supports 21 for items being cooked, as also shown in FIG. 4. Instead of a glass ceramic plate 19 it is also possible to employ other—preferably fast-reacting—coverings, for example a thin metal plate.

The high-fitted cooking appliance can with the aid of an operating knob provided in the operating panel 12 be switched to a cooking-hob operating mode or bottom-heat operating mode, which are explained below.

The cooking-hob heating elements 16, 17 can in the cooking-hob operating mode be controlled individually via the control circuit 13 by means of control elements 11 provided in the operating panel 12, while the panel heating element 18 remains in the non-operating state.

The cooking-hob operating mode can be used with the base door 7 lowered, as is shown in FIG. 1. However it can also be used within the scope of an energy-saving function when the cooking chamber 3 is closed with the base door 7 raised.

In the bottom-heat operating mode not only the cooking-hob heating elements 16, 17 but also the panel heating element 18 are controlled by the control device 13.

To achieve maximally even browning of items being cooked using the bottom-heat mode it is crucial for the cooking area 15 providing the bottom heat to distribute the heating output evenly across the surface of the cooking area 15, although the heating elements 16, 17, 18 have different nominal outputs. The heating elements 16, 17, 18 are therefore preferably not switched to continuous operation by the control circuit 13; the power supply to the heating elements 16, 17, 18 is instead clocked. The different nominal heat outputs of the heating elements 16, 17, 18 are therein reduced individually in such a way that the heating elements 16, 17, 18 will distribute the heating output evenly across the cooking area's surface.

FIG. 4 shows schematically the position of a fan 23, for example for producing circulating air in the case of hot-air operation or for ducting fresh air inward. Further provided attached to a top side of the muffle 5 is a top-heat heating element 22 that can be embodied as of single-circuit or multiple-circuit design, for example having an inner and an outer circuit. There can also be further heating elements—not shown here for the sake of greater clarity—, such as a ring-shaped heating element, between the back wall of the housing 1 and the muffle. The various operating modes such as, for example, also top-heat, hot-air, or quick-heat mode can be set by means of the control circuit 13 by appropriately switching or setting the heat output of the heating elements 16, 17, 18, 22, possibly with activating of the fan 23. The heat output can be set by means of suitable clocking. The cooking area 15 can furthermore be embodied otherwise, for example with or without a frying zone, as a pure—single-circuit or multiple-circuit—warming zone without cooking troughs, and so forth. The housing 1 has a seal 24 toward the base door 7.

The operating panel 12 is arranged chiefly on the front of the base door 7. Other arrangements are alternatively also conceivable, for example on the front of the housing 1, distributed over different partial panels, and/or in part on side surfaces of the cooking appliance. Further embodiments are possible. The control elements 11 are not limited in their structural design and can include, for example, operating knobs, toggle switches, pushbuttons, and membrane keys that include display elements 14, for example LED, LCD, and/or touchscreen displays.

FIG. 5 is a schematic front view, not to scale, of a high-fitted cooking appliance in which the base door 7 is open and resting on the work plate 8. The closed condition is indicated by dashed lining.

In that embodiment variant there are two displacement switch panels 25 on the front of the permanently attached housing 1. Each displacement switch panel 25 includes two pushbuttons, namely a top CLOSE pushbutton 25a for a base door 7 moving upward in the closing direction and a bottom OPEN pushbutton 25b for a base door 7 moving downward in the opening direction. The base door 7 will without automatic operation (see below) move upward, if possible, only through continuously simultaneously pressing the CLOSE buttons 25a on both displacement switch panels 25; the base door 7 will also move downward, if possible, only through continuously simultaneously pressing the OPEN buttons 25b on both displacement switch panels 25 (manual operation). Since the user will be more attentive to operation during manual operation and, moreover, both hands are used in that case, jamming protection will then only be optional. Displacement switch panels 26 are in an alternative embodiment variant attached to opposite outer sides of the housing 1 along with corresponding CLOSE buttons 26a and OPEN buttons 26b, as indicated by dotted lining.

The control circuit 13 that is indicated by dot-and-dash lining and located inside the base door 7 behind the operating panel 12 switches the drive motor 9 in such a way that the base door 7 will start moving gently, i.e. not abruptly through simple turning on of the drive motor 9 but by means of a defined ramp.

The control circuit 13 includes in that exemplary embodiment a memory unit 27 for storing at least one target or displacement position P0, P1, P2, PZ of the base door 7, preferably with volatile memory chips, for example DRAMs. After one of the buttons 25a, 25b or, as the case may be, 26a, 26b on the displacement switch panels 25 or, as the case may be, 26 has been actuated, if a target position P0, P1, P2, PZ has been stored the base door can continue moving automatically in the direction set until the next target position has been reached or one of the buttons 25a, 25b or, as the case may be, 26a, 26b has been actuated again (automatic operation). The bottommost target position PZ corresponds in that exemplary embodiment to the maximum opening, the (zero) position P0 corresponds to the closed condition, and P1 and P2 are freely configurable intermediate positions. When the last target position for a direction has been reached, it will thereafter be necessary to proceed using manual operation if that is possible (meaning if the last end positions do not correspond to a maximum open condition or to the closed final condition). Analogously, if no target position has been stored for a direction—which would be the case, for example, for an upward direction to the closed position if only PZ has been stored but not P0, P1, P2—, a displacement in said direction will have to take place using manual operation. Automatic operation will not be possible if no target position has been stored, for example in the case of a new installation or following a disconnection from the a.c. power supply. Jamming protection will preferably have been activated if the base door 7 is displaced using automatic operation.

Automatic and manual operation are not mutually exclusive: The base door 7 will through continuously actuating the displacement switch panel(s) 25, 26 also move using manual operation if a target position could be moved to in said direction. It is therein possible to, for example, specify a maximum actuating time, for instance 0.4 seconds, for the displacement panels 25 or, as the case may be, 26, or for the associated buttons 25a, 25b or, as the case may be, 26a, 26b, for activating automatic operation.

A target position P0, P1, P2, PZ can be any position of the base door 7 between and including the zero position P0 and the maximum open position PZ. However the maximum stored open position PZ does not have to be the position resting on the work plate 8. The target position P0, P1, P2, PZ can be stored with the base door 7 at the desired target position P0, P1, P2, PZ by, for example, actuating an actuating button 28 in the operating panel 12 for several seconds (for example two seconds continuously). For the sake of greater clarity existing optical and/or acoustic signaling devices that feed out relevant signals when a target position has been stored have not been drawn. The desired target position P0, P1, P2, PZ requiring to be set is moved to by, for example, —in this exemplary embodiment—operating the displacement switch panels 25 or, as the case may be, 26 with both hands and performing a manual displacement up to said position.

Just one target position or, as shown in this exemplary embodiment, also a plurality of target positions P0, P1, P2, PZ can be capable of being stored in the memory unit 27. In the case of a plurality of target positions P0, P1, P2, PZ, they can be moved to consecutively by actuating the corresponding displacement buttons 25a, 25b or, as the case may be, 26a, 26b. A plurality of target positions P0, P1, P2, PZ will allow the high-fitted cooking appliance to be matched conveniently to the different operating heights desired by several users. The target position(s) can advantageously be cleared and/or overwritten. For example just one target position can in one embodiment variant be stored in the open condition while the zero position P0 will be detected automatically and can be moved to automatically. The zero position P0 must alternatively also be stored so that it can be moved to automatically.

For an ergonomic use it is particularly advantageous for the or a target position P1, P2, PZ to open the base door 7 at least approximately 400 mm to approximately 540 mm (meaning P1-P0, P2-P0, PZ-P0≧40 cm to 54 cm). The supports 21 for items being cooked will at that opening extent be easy to insert into the securing parts 20. It is therein favorable for the viewing window 4 to be mounted approximately at the user's eye level or somewhat lower, for example by means of a template indicating the cooking appliance's dimensions.

Not drawn is a power-failure buffer for bridging power outages lasting approximately 1 to 3 s, preferably up to 1.5 s.

The drive motor 9 shown in FIG. 1 has at least one sensor unit 31, 32 located on a motor shaft 30, where applicable in front of or behind a gear, for measuring a displacement path or, as the case may be, a position and/or speed of the base door 7. The sensor unit can include, for example, one or more induction, Hall, optical, or OFW sensors, and so forth. For simple path and speed measuring two Hall (sub-)elements 31 are here attached displaced through 180° to the motor shaft 30—thus placing them mutually opposite—and a Hall sensing element 32 is statically attached to that area of the motor shaft at a distance. When a Hall element 31 then passes the sensing element 32 when the motor shaft 30 turns, a measuring or sensor signal will be produced that is very approximately digital. Two signals will hence be fed out with (not necessarily) two Hall elements 31 when the motor shaft 30 turns once. The speed vL of the base door 7 can be determined by evaluating the time of said signals, for example their time difference, for instance by way of comparison tables or through real-time conversion in the control circuit 13. A displacement path or, as the case may be, a position of the base door 7 can be determined by adding or, as the case may be, subtracting the measurement signals.

A speed-regulating means can implement the speed via, for example, a PWM-controlled power-semiconductor device.

For determining the zero point, travel measuring is automatically realigned by initializing in the zero position P0 of the base door 7 each time it is moved so that for example a faulty sensor-signal output or, as the case may be, reception will not propagate.

The drive motor 9 can also be operated by actuating both displacement switch panels 25 or 26 with the main switch 29 deactivated.

Instead of two separate switches per displacement panel 25, 26 a single switch per displacement panel is also possible, for example a toggle switch that has a neutral position and switches only under pressure. Other forms are also possible. The nature and arrangement of the control elements 28, 29 of the operating panel 12 are not limited, either.

The arrangement of the control circuit 13 and the way it is distributed is therein flexible and not limited, so it can also include a plurality of boards, for example a display board, a control board, and a lift board, that are spatially separated.

A 4-mm opening extent can be detected by means of end switches 33 which on actuation deactivate jamming protection.

The high-fitted cooking appliance can be embodied also without a memory unit 27, with automatic operation then not being possible. That can be expedient for increased operating safety, for example as a safeguard against jamming.

FIG. 6 is a graph, not to scale, plotting the displacement speed vL of the base door 7 in mm/s against said door's position in mm from the zero position P0 for a displacement of the base door 7 from the closed condition at P0=0 mm to PZ=maximum opening at, in this case, 530 mm during a manual displacement operation (thus without automatic-displacing means) as well as, indicated by the dotted arrow, stopping of the displacement movement between P0 and PZ. The curve runs in the direction of the arrow, meaning from right to left. The downward arrows above the curve indicate actuating of the operating panel 12.

The downward displacement movement of the base door 7 starts with two-handed actuating of the displacement switch panels 25, 26 or, as the case may be, of the OPEN switches 25b or, as the case may be, 26b, as indicated by the top left vertical arrow. The control circuit 13 regulates the drive motor 9 in such a way that the base door 7 will be moved gently, i.e. with a defined ramp R1, up to its setpoint speed of, in this case, vL=50 mm/s. The ramp R1 is in that case linear. So the drive motor 9 is not simply turned on.

The displacement movement is as a result also load-independent, in particular independent of any additional loading of the base door 7 or of any changes in the frictional conditions within the mechanism. An initial variable for this can be the rotational speed, measurable by, for example, Hall sensors, of the drive motor 9.

The base door 7 moves constantly downward after reaching the setpoint speed of vL=50 mm/s until approaching the maximum opening PZ determined by the maximum displacement of the base door 7 specified in its design or by reaching of the work plate 8. It is assumed in that figure that the maximum opening PZ specified in the design is reached. In that case the control circuit 13 will detect said approaching and automatically brake the base door 7 gently, i.e. with a defined ramp R2, at PZ. Both ramps R1 and R2 can have other inclinations or shapes. Approaching of the base plate can be detected by end switches 33 and/or through monitoring of the displacement path.

If one or both of the displacement switches 25b, 26b is/are released, as indicated by the top left vertical arrow, the base door 7 will stop abruptly without a ramp, as indicated by the dotted arrow. So although moving starts gently in that mode, it will stop abruptly—except when the final position has been reached.

The cooking chamber 3 will not be opened, meaning the base door 7 will not be displaced from the zero position P0, if an opening-protection means is active, so if, for example, a specific temperature in the cooking chamber, for example 425° C. or 600° F., has been exceeded or a child-protection means has been activated.

FIG. 7 is a graph, not to scale, analogous to FIG. 6 relating to a displacement of the base door 7 from the closed condition to a stored position P1=476 mm during automatic displacement operation.

In that case the base door 7 starts moving automatically toward the position P1 through brief actuating of one of the OPEN switches 25b or, as the case may be, 26b, as indicated by the top right vertical arrow. The base door 7 will in that case, too, start being moved gently (right ramp) and braked automatically (left ramp). With that embodiment variant it is possible during automatic operation to select between two fixed setpoint speeds, namely 75 mm/s (dashed line) and 50 mm/s (unbroken line), with the slower speed being favorable especially for older users. The slower speed setting is the default in, for example, the condition as supplied. More than two speed settings or, as the case may be, setpoint speeds can also be provided; flexible setting of the setpoint speed(s) by the user is also conceivable. It is favorably also possible to change over between at least two speed settings of 50 mm/s and 65 mm/s, for example when the appliance is being initialized.

FIG. 8 is a graph, not to scale, relating to a displacement of the base door 7 from the maximum open position PZ to the zero position P0, meaning to the closed condition, during manual operation.

The upward displacement movement of the base door 7 starts with two-handed actuating of the CLOSE switches 25a or, as the case may be, 26a, as indicated by the top left vertical arrow. The control circuit 13 regulates the drive motor 9 in such a way that the base door 7 will be moved gently from PZ up to its setpoint speed of vL=50 mm/s, then be moved constantly at that setpoint speed (to the right).

The control circuit 13 will detect approaching of the zero position P0 and gently brake the base door 7 in good time in advance. However, instead of its then continuing down to the zero position P0 directly by means of the linear ramp, 4 mm before the zero position P0 speed-dependent controlling will be switched over to controlling by means of a defined voltage, i.e. through supplying the motor 9 with an appropriate voltage. That will allow maximum force to develop with blocking of the drive motor 9. Said voltage will differ depending on the prior displacement history (additional loading, frictional conditions etc.). The 4-mm opening extent is detected through travel measuring or additionally or alternatively by way of the end switches 33. It is also possible to dispense with jamming protection in the range from P0 to P0+4 mm.

If, as in FIG. 6, one or both of the displacement switches 25b, 26b is/are released, as indicated by the top right vertical arrow, the base door 7 will stop abruptly without a ramp, as indicated by the dotted arrow.

FIG. 9 is a graph, not to scale, relating to a displacement of the base door 7 from a stored position P1=476 mm to the closed condition P0 during automatic displacement operation. In contrast to the manual displacement operation shown in FIG. 8, only one of the CLOSE switches 25a, 26a now needs to be briefly actuated, as indicated by the top vertical arrow. The base door 7, analogous to FIG. 7, will then only move in the other direction. When the zero position P0 is approached, then analogously to the situation shown in FIG. 8 for the last 4 mm of opening the brake ramp will change from a speed-controlled condition to one controlled by load or, as the case may be, closing force.

FIG. 10 is a graph, analogous to FIG. 8, in the case of which jamming now occurs at a setpoint speed of vL=50 mm/s, as indicated by the top vertical arrow. The speed of the base door 7 will drop when a hand or a pot for example becomes jammed between the base door 7 and the housing 1 because the object will prevent further displacing. The lifting speed is here monitored by, for example, evaluating the motor shaft's sensor signals, with, for example, the time between the measuring signals or, as the case may be, pulses being evaluated. The motor current is monitored only as a secondary measure, which is a somewhat slower method. The force that can be produced by the motor 9 for displacing is in particular limited to prevent accidents due to too tight jamming (see also FIGS. 12 and 13). Any deviations from the setpoint speed will be detected by the control circuit 13 based on, for example, a deviation in speed or change therein over time. The base door will then reverse so that the object can be removed; an acoustic, for instance, warning signal may also be fed out. The base door 7 will thereafter only start moving once a displacement-button panel 25, 26 has been actuated again appropriately.

So that a jamming incident will not be triggered erroneously owing to, for example, changed additional loading or a change in the mechanism's running properties, firstly, jamming protection can be activated only once the base door 7 has reached its setpoint speed (the base door 7 will stop immediately if a displacement button 25a, 25b, 26a, 26b is released before that) and, secondly, a plurality of sensor signals can be evaluated, for example averaged.

FIG. 11 shows a jamming incident (top vertical arrow) occurring while the base door 7 is being displaced into an open target position P1 during automatic operation during which an object becomes jammed between the underside of the base door 7 and the work plate 8. In that case jamming can be detected via two redundant end switches that detect—in particular uneven—unloading of the base door 7, whereupon the drive motor 9 will reverse. The maximum permitted force-time profile (see FIGS. 12 and 13) will therein not be exceeded.

FIG. 12 shows as a first force-time profile FT1 a maximum force F in N that can be applied to the base door 7 during a jamming incident occurring during displacement in a closing direction (meaning upward), plotted against the expired time t in s.

During a jamming incident at t=0 s the possible closing force is limited for 5 s to 100 N, corresponding approximately to 10 kg. That will be expedient if, for example, the motor 9 is stepped up by the control device 13 in order to maintain the setpoint speed. This will ensure in particular that parts of the body will not be injured. If the base door is pulled for 5 s with a force of (at most) 100 N, the maximum force that can be applied will be further reduced to 25 N, for example for 5 seconds. Said force level can thereafter either be maintained or further reduced to, for example, 0 N. It must be emphasized that said force-time profile FT1 indicates only the maximum force that can be applied and that the force actually applied will as a rule be less if, for example, the jamming incident is detected by the control device 13 and the base door 7 reversed accordingly after t=0.5 s, whereupon the force being applied will drop from 100 N to, for instance, 0 N.

The maximum force threshold of 100 N can also apply to other displacement situations.

FIG. 13 shows as a second force-time profile FT2 a maximum force F in N that can be applied to the base door 7 during a jamming incident occurring during displacement in an opening to the base door 7 during a jamming incident occurring during displacement in an opening direction (meaning downward), plotted against the expired time t in s. The drive motor 9 can here in a first block of t=[0 s; 0.5 s] be applied to the base door 7 with a force of up to 400 N, thereafter at t=[0.5 s; 5 s] with a force of 150 N, and thereafter with a force of 25 N.

The time intervals and force thresholds of the force-time profiles FT1, FT2 can of course be accommodated to physical structure and other boundary conditions.

LIST OF REFERENCES

  • 1 Housing
  • 2 Wall
  • 3 Cooking chamber
  • 4 Viewing window
  • 5 Muffle
  • 6 Muffle opening
  • 7 Base door
  • 8 Work plate
  • 9 Drive motor
  • 10 Lifting element
  • 11 Control element
  • 12 Operating panel
  • 13 Control circuit
  • 14 Display elements
  • 15 Cooking area
  • 16 Cooking-hob heating element
  • 17 Cooking-hob heating element
  • 18 Panel heating element
  • 19 Glass ceramic plate
  • 20 Securing part
  • 21 Support for items being cooked
  • 22 Top-heat heating element
  • 23 Fan
  • 24 Seal
  • 25 Displacement switch panel
  • 25a Displacement switch, upward
  • 25b Displacement switch, downward
  • 26 Displacement switch panel
  • 26a Displacement switch, upward
  • 26b Displacement switch, downward
  • 27 Memory unit
  • 28 Actuating button
  • 29 Main switch
  • 30 Motor shaft
  • 31 Hall element
  • 32 Sensing element
  • 33 End switch
  • FT1 First force-time profile
  • FT2 Second force-time profile
  • P0 Zero position
  • P1 Intermediate position
  • P2 Intermediate position
  • PZ Final position
  • R1 Speed ramp
  • R2 Speed ramp
  • vL Displacement speed of the base door