U.S. patent application number 12/087969 was filed with the patent office on 2009-01-01 for cooking appliance, especially built-in wall cooking appliance, and method for controlling a cooking appliance.
This patent application is currently assigned to BSH Bosch und Siemens Hausgeraete GmbH. Invention is credited to Ingo Bally, Alexander Dinkel, Kerstin Feldmann, Wolfgang Fuchs, Martin Keller, Angelika Namberger, Maximilian Neuhauser, Klemens Roch, Wolfgang Schnell, Guenter Zschau.
Application Number | 20090001069 12/087969 |
Document ID | / |
Family ID | 37948242 |
Filed Date | 2009-01-01 |
United States Patent
Application |
20090001069 |
Kind Code |
A1 |
Bally; Ingo ; et
al. |
January 1, 2009 |
Cooking Appliance, Especially Built-In Wall Cooking Appliance, and
Method For Controlling a Cooking Appliance
Abstract
A cooking appliance including a high-level cooking appliance
having a muffle including a muffle compartment defining a cooking
compartment with a muffle opening, a door for movement between an
open and closed relationship with the muffle opening and a drive
device controlled by a control device for moving the door, the
cooking appliance including a detector for determining a trapping
condition wherein an object becomes trapped as the door is being
moved, wherein the detector is configured for detecting the
trapping state by comparing a door movement parameter with a
threshold value associated with door movement.
Inventors: |
Bally; Ingo; (Traunstein,
DE) ; Dinkel; Alexander; (Unterwoessen, DE) ;
Feldmann; Kerstin; (Bretten, DE) ; Fuchs;
Wolfgang; (Altenmarkt a.d. Alz, DE) ; Keller;
Martin; (Traunreut, DE) ; Namberger; Angelika;
(Altenmarkt a.d. Alz, DE) ; Neuhauser; Maximilian;
(Chieming/Egerer, DE) ; Roch; Klemens; (Trostberg,
DE) ; Schnell; Wolfgang; (Trostberg, DE) ;
Zschau; Guenter; (Traunwalchen, DE) |
Correspondence
Address: |
BSH HOME APPLIANCES CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
100 BOSCH BOULEVARD
NEW BERN
NC
28562
US
|
Assignee: |
BSH Bosch und Siemens Hausgeraete
GmbH
Munchen
DE
|
Family ID: |
37948242 |
Appl. No.: |
12/087969 |
Filed: |
December 18, 2006 |
PCT Filed: |
December 18, 2006 |
PCT NO: |
PCT/EP2006/069832 |
371 Date: |
July 18, 2008 |
Current U.S.
Class: |
219/413 ;
219/493 |
Current CPC
Class: |
F24C 15/027
20130101 |
Class at
Publication: |
219/413 ;
219/493 |
International
Class: |
F24C 7/08 20060101
F24C007/08; F24C 15/02 20060101 F24C015/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2006 |
DE |
10 2006 004 390.1 |
Claims
1-38. (canceled)
39. A cooking appliance including a high-level cooking appliance
having a muffle including a muffle compartment defining a cooking
compartment with a muffle opening, a door for movement between an
open and closed relationship with the muffle opening and a drive
device controlled by a control device for moving the door, the
cooking appliance comprising a detector for determining a trapping
condition wherein an object becomes trapped as the door is being
moved, wherein the detector is configured for detecting the
trapping state by comparing a door movement parameter with a
threshold value associated with door movement.
40. The cooking appliance according to claim 39 wherein the door
movement parameter corresponds to a speed of movement of the door
and the threshold value corresponds to a permitted minimum
speed.
41. The cooking appliance according to claim 39 wherein the door
movement parameter corresponds to door acceleration and the
threshold value corresponds to a permitted minimum door
acceleration.
42. The cooking appliance according to claim 39 wherein the
monitoring of the trapping state dependent on the threshold value
is activated within a predetermined movement path of the door.
43. The cooking appliance according to claim 42 wherein the
movement path of the door includes a zero position corresponding to
a closed position of the door.
44. The cooking appliance according to claim 39 wherein monitoring
of the trapping state is activated within the last movement path of
the door before a zero position corresponding to a closed position
of the door is reached.
45. The cooking appliance according to claim 39 wherein monitoring
of the trapping state is activated within the last 15 mm,
especially the last 10 mm, especially the last 5 mm movement path
of the door before a zero position corresponding to a closed
position of the door is reached.
46. The cooking appliance according to claim 39 wherein monitoring
of the trapping state dependent on the threshold value is activated
after a switchover from a different trapping state monitoring
method.
47. The cooking appliance according to claim 39 and further
comprising an end switch in operational association with the door
wherein monitoring of the trapping state dependent on the threshold
value is activated after activation of the end switch.
48. The cooking appliance according to claim 39 wherein monitoring
of the trapping state dependent on the threshold value is activated
during a switchover to a force-regulated closure movement of the
door.
49. The cooking appliance according to claim 39 and further
comprising a speed measurement device for measuring a speed of door
movement.
50. The cooking appliance according to claim 39 and further
comprising a speed measurement device for measuring a speed of door
movement wherein an uncontrolled reduction in the speed of door
movement is indicative of an object becoming trapped in the
door.
51. The cooking appliance according to claim 39 and further
comprising a speed measurement device for measuring a speed of door
movement wherein a deviation from a setpoint speed of door movement
is indicative of an object becoming trapped in the door.
52. The cooking appliance according to claim 50 wherein the
monitoring of the speed of door movement includes monitoring door
acceleration.
53. The cooking appliance according to claim 39 wherein the speed
measuring device includes at least one sensor operationally
disposed on a motor shaft of the drive device for generating
signals corresponding to rotation of the motor shaft.
54. The cooking appliance according to claim 53 wherein the at
least one sensor is formed as a Hall sensor configured for
generating two sensor signals for each rotation of the motor
shaft.
55. The cooking appliance according to claim 53 wherein the speed
of door movement determined by a time difference between the sensor
signals.
56. The cooking appliance according to one of the claims 53 and
further comprising means for evaluating and averaging a plurality
of sensor signals.
57. The cooking appliance according to claim 39 and further
comprising means for reversing a direction of door movement when an
object becomes trapped in the door.
58. The cooking appliance according to claim 39 and further
comprising means for controlling the direction of displacement
movement of the door as a function of the door speed.
59. The cooking appliance according to claim 58 wherein anti-trap
protection is only activated when the setpoint speed of the door is
reached.
60. The cooking appliance according to claim 39 and further
comprising means for preventing a predetermined door driving force
from being exceeded when an object becomes trapped in the door.
61. The cooking appliance according to claim 39 and further
comprising at least one end switch operationally disposed in an
area between the muffle opening and door and that an actuation of
the at least one end switch deactivates an anti-trap protection
device.
62. The cooking appliance according to claim 61 wherein the at
least one end switch is able to be actuated within an opening
dimension of about 4 mm between the muffle opening and the
door.
63. The cooking appliance according to one of the claims 61 and
further comprising means for moving the door with a predetermined
force toward the muffle opening upon actuation of the at least one
end switch.
64. The cooking appliance according to claim 39 and further
comprising a high-level cooking appliance wherein the muffle
opening is formed with a downwardly directed muffle opening and the
door is formed as a base unit door.
65. A method for operating a cooking appliance including a
high-level cooking appliance having a muffle including a muffle
compartment defining a cooking compartment with a muffle opening, a
door for movement between an open and closed relationship with the
muffle opening and a drive device controlled by a control device
for moving the door, the method comprising the steps of providing a
detector for determining a trapping condition wherein an object
becomes trapped as the door is being moved, and detecting an object
trapped in the door by a comparison of a door movement parameter
with a threshold value associated with door movement.
66. The method according to claim 65 wherein the threshold value is
based on a permitted minimum speed.
67. The method according to claim 65 wherein the threshold value is
based on a differential speed.
68. The method according to claim 65 and further comprising the
step of activating monitoring of the trapping state within a
predetermined movement path of the door.
69. The method according to claim 68 and further comprising the
step of defining the movement path of the door before a zero
position of a closed door corresponding to a closed position.
70. The method according to claim 65 and further comprising the
step of activating monitoring a trapping state within the last
movement path of the door before it reaches a zero position
corresponding to a closed position.
71. The method according to claim 69 and further comprising the
step of activating monitoring of a trapping state within the last
15 mm, especially 10 mm, especially 5 mm movement path of the door
before it reaches the zero position.
72. The method according to claim 65 and further comprising the
step of activating monitoring of the trapping state dependent on
the threshold value in conjunction with or after a switching off a
different anti-trap protection method.
73. The method according to claim 65 and further comprising the
step of activating monitoring of the trapping state dependent on
the threshold value in conjunction with or after an activation of
an end switch.
74. The method according to claim 65 and further comprising the
step of activating monitoring of the trapping state dependent on
the threshold value during a switchover to a force-regulated
closing movement of the door.
75. The method according to claim 65 and further comprising the
step of reversing a direction of door movement in the event of a
trapping situation.
76. The method according to claim 65 wherein the step of detecting
a speed of door movement results in detecting door speed reduced in
an uncontrolled manner a trapping situation is indicated.
Description
[0001] The present invention relates to a cooking appliance,
especially a high-level cooking appliance, with at least one muffle
delimiting a cooking compartment which has a muffle opening, a door
for closing off the muffle opening and a drive device controlled by
a control device for moving the door.
[0002] A high-level cooking appliance is known from DE 102 28 140
A1 in which the trapping of objects at the base unit door can be
detected by a number of anti-trap protection switches, able to be
operated independently of each other, between the base unit door
and the muffle frame. In this case an increase in pressure in a
door seal with a hollow profile can also be evaluated.
[0003] An anti-trap protection system which is initiated by
different tensions on pull cables driving the base unit door is
described in DE 101 64 239 A1. A torque sensor is also described,
which detects a load moment on the drive shaft of an electric
motor. Tension sensors, piezoelectric sensors and also deformation
or strain/expansion sensors are listed as sensors for this
purpose.
[0004] DE 102 88 141 A1 also describes an optoelectronic sensor for
detecting a trapping condition, which uses the amount of reflected
light for switching.
[0005] The disadvantage is that the anti-trap detection systems
described are either relatively slow (tension sensor) or imprecise
or error-prone (opto sensor) and also require increased
installation effort.
[0006] Also the primary disadvantage of anti-trap protection
systems is that an instance of a small and elastic object becoming
trapped, for example a child's finger, is not detected or is only
detected after an the object has sustained injury by being squashed
too much. A further disadvantage lies in the fact that, especially
in the case of end-position switches or anti-trap switches built
into the front side of the cooking appliance, if a heavy load is
placed on the door, bending causes its front edge to be lower than
its rear edge, so that the switches may possibly not function
absolutely securely.
[0007] Another disadvantage here is an activation of a closing
process for the door, in which, shortly before the closed state is
reached, a switchover is performed from anti-trap operation in
which a switch or a function is used to detect a trap condition, to
a closure mode for detecting the closed state.
[0008] The object of the present invention is thus to provide a
fast, simple and accurate anti-trap detection system for a cooking
appliance of the type described above.
[0009] The present object is achieved by the cooking appliance with
the features of claim 1 and a method as claimed in claim 27.
[0010] The preference is thus for a cooking appliance, especially a
high-level cooking appliance, with at least one muffle delimiting a
cooking compartment which has a muffle opening, a door for closing
off the muffle opening and a drive device controlled by a control
device for moving the door whereby, in the event of an object being
trapped when the door is moved, a trapping condition is detected,
with the trapping condition being detected by comparing a parameter
pertaining to a displacement movement of the door with a threshold
value belonging to this parameter and by the system detecting when
this threshold has been reached and/or exceeded. Exceeded in this
case means that the value is exceeded from below or above (also
called undershooting). In such cases the comparison between the
current value and threshold value always relates to the current
direction of movement of the door, i.e., that the speed comparison
is undertaken independently of the direction of movement, meaning
that it relates above all to the absolute speed. In the same sense
it is assumed, that in the case of positive acceleration
(acceleration) of the door .DELTA.v or .DELTA.v/.DELTA.t>0,
whereas with negative acceleration (braking) .DELTA.v or
.DELTA.v/.DELTA.t<0.
[0011] The threshold value preferably corresponds to a permitted
minimum speed and/or a differential speed or speed difference per
unit of time or acceleration. Such a threshold value can be
employed as an additional or independent criterion. A differential
speed can in this case be determined easily by an increase in the
duration of a measuring signal of a Hall sensor for monitoring the
rotation of a drive shaft. Also usable are further parameters such
as a motor current or a load of the base unit door.
[0012] The threshold value can be determined as the difference from
the setpoint value (e.g. threshold speed vS<setpoint speed vR*x
%), so that the trapping condition is detected if the current speed
vL of the base unit door reaches threshold value vS or exceeds it
from above, i.e. falls below it, if is moving at only x % of the
setpoint speed. This corresponds to the condition vS.gtoreq.vL.
Likewise the threshold value can be determined as the difference
between the threshold value differential speed vS as setpoint
differential speed .DELTA.vR*y %, so that trapping is detected if
the current differential speed .DELTA.vL or acceleration of the
base unit door reaches the threshold value .DELTA.vS or exceeds it
from above, i.e. undershoots it, if it is only still moving at y %
of the setpoint speed. In this case a faster braking than intended
(as in the case of trapping), means that the trapping condition
.DELTA.vS.gtoreq..DELTA.vL is triggered for a predetermined period
of time. The threshold value preferably depends on the setpoint
value, i.e. that vS=vS(vR) or .DELTA.vS=.DELTA.vS(.DELTA.vR) can
apply for example. However a fixed predetermined threshold value
can also be assumed, for example, If this anti-trap protection
system is only applied in sections, e.g. only in an area of a ramp
or in the area of a constant setpoint speed. For example the
threshold value can then be predetermined as a fixed value in
relation to the setpoint speed actually reached most (e.g. vR=50
mm/s), e.g. in a memory unit of a control unit, e.g. vS=40 mm/s.
This can be prespecified for a number of sections, e.g. from a
lookup table.
[0013] Monitoring a differential speed is especially advantageous
in respect of a partly elastic and small object such as a child's
finger becoming trapped. In such a case the door does not brake
abruptly under some circumstances, which would be able to be
detected securely with a pure speed monitoring method. Monitoring
of the differential speed may be more sensitive here. Especially
preferable is a combination of the two methods.
[0014] The monitoring of the trapping condition depending on the
threshold value is preferably activated within a predetermined
movement path of the door. If this movement path of the door
especially lies within the last movement path before a zero
position, which corresponds to a closing position of a closed door,
an area can also be monitored in which for example an end switch
has already been activated or other methods for monitoring a
trapping condition can no longer be used. The trapping condition is
preferably monitored within the last 15 mm, especially 10 mm,
especially 5 mm of movement path of the door before the zero
position is reached. Activation of the end switch in this case is
to be understood not only as the detection of a secure end closed
position but optionally also a first activation even before the
final closed position of the door on reaching a specific approach
distance of the door from the muffle.
[0015] The monitoring of the trapping condition depending on the
threshold value is especially active after a deactivation of a
first trapping condition monitoring method, i.e. continues to be
activated or is switched on at this point. When the door approaches
the muffle at a distance of less than especially 1 cm, there can be
a secure switchover of an activation of a closure process for the
door from an anti-trap protection mode in which a switch or a
function serves to detect the trapping state, to a closure mode for
securely detecting a closed state. This is secure because, after
the switchover, continued monitoring is still undertaken
alternately or at least by monitoring the closure speed. The
monitoring of the trapping state depending on the threshold value
is undertaken accordingly in this case especially after a
switchover of a first monitoring type for monitoring a trapping
state by means for example of switches shortly before a final
closure movement of the door.
[0016] Advantageously, even after deactivation of a monitoring
method depending especially on a constant speed also especially
during braking of the door, i.e. during speed which changes over
time, an anti-trap protection method can be provided.
[0017] The monitoring of the threshold value is preferably
activated after activation of an end switch for signaling of a last
closure area, so that an anti-trap protection method can be
provided even in a narrow space in which a child's finger could be
trapped.
[0018] The monitoring of the trapping state depending on the
threshold value during a switchover to a force-regulated closure
movement of the door is then activated especially if the final
closure process is no longer regulated by speed but by force.
[0019] To this end the cooking appliance, which is especially a
high-level cooking appliance, but can also be a cooking appliance
with an oven carriage, is equipped with a speed measurement device
for determining speed of movement of the door. The speed
measurement device allows the detection of an object being trapped
in the door by monitoring its speed of movement. In this case the
displacement movement does not have to be speed-regulated, but can
for example also be regulated depending on the load via the motor
voltage or the motor current. Advantageously however the
displacement movement of the door is also controlled or regulated
as a function of the speed--i.e. also independent of the load, e.g.
via a central control unit.
[0020] It is especially useful when the door is being closed for
there to be at least one end switch also present, which is arranged
in the area between muffle opening or frame and door, with an
activation of the at least one end switch deactivating the
anti-trap protection device or a first, other type of anti-trap
protection, i.e. ending the protective measures. This end switch
preferably switches at an opening distance of less than one
centimeter, especially in a range of 9-4 mm, which is so small that
none of the usual objects in the household could be trapped within
the space. On activation of the at least one end switch the door is
pushed with a defined force--and no longer speed-controlled--onto
the muffle opening. Despite this it is advantageously guaranteed
that when the door is closed, it does not reverse in an undesired
manner, but in the case of a possible trapping of an object in the
end phase of the closure, can still reverse.
[0021] In particular a non-abrupt premature stopping of the closing
movement represents an indication of a trapped child's finger, so
that the door is immediately opened again in such a case,
especially by an opening distance sufficient to allow the finger to
be pulled out. Such a non-abrupt premature stopping of the closure
movement can be detected especially safely by monitoring a speed
differential value.
[0022] To avoid even smaller objects or especially a child's finger
becoming trapped however, there is preferably no complete
deactivation provided but a switchover to a modified protection is
undertaken.
[0023] This speed-based anti-trap protection method has the
advantage of reacting comparatively fast, of being able to receive
precise input data and of being able to be implemented relatively
simply without any great constructional measures.
[0024] The monitoring of the speed of movement can be directed to
reducing the speed of movement which is uncontrolled and thus not
deliberately included in the regulation. This can occur by a value
measured by the speed measurement device deviating by a percentage
value from a setpoint value. If the deviation is above or below a
specific threshold value, it is assumed that something has become
trapped. For example if a door can no longer be moved at the
setpoint speed selected since an object is preventing it from doing
so, then the speed falls accordingly. This evaluation and
monitoring can be undertaken in a central control device for
example, e.g. via suitable microcontrollers.
[0025] As an alternative or in addition a--mostly too rapid--change
of the speed of movement over time can trigger the anti-trap
system, if for example the door is braked more quickly than
provided for in the event of an object becoming trapped.
[0026] Naturally the values are selected so that speed fluctuations
caused by the process for regulating the movement of the door do
not generally activate the anti-trap system. In addition the
anti-trap protection methods described in the prior art can also be
used, such as measuring the motor current.
[0027] It is advantageous for the speed measurement device to
include at least one sensor on a motor shaft of the drive device,
especially of a drive motor, through which corresponding sensor
signals are generated as the motor shaft turns. This makes a
comparatively fast reaction possible. The sensor signals are
directly or indirectly a measure of the speed of movement of the
door. It is then especially useful for the at least one sensor to
be a Hall sensor which outputs two sensor signals per revolution of
the motor shaft. The Hall sensor system is simple to install, fast
and insensitive. Advantageously two Hall (part) elements are
accommodated on the motor shaft, so that two signals are output for
one revolution of the motor shaft. By evaluating these signals over
time a speed of the base unit door can be determined, for example
using comparison tables or real time conversion. Preferably the
speed of movement is detected by a time difference between the
sensor signals.
[0028] For stable speed determination it is useful for a number,
especially more than two, sensor signals to be evaluated. It is
also advantageous here for a number, especially more than two,
sensor signals to be averaged.
[0029] In particular it is advantageous for the direction of
movement of the door to be reversed after detection of the
trapping.
[0030] To this and an anti-trap protection device can be present
which takes over the monitoring of the trapping condition and/or
implementation of measures to be performed in the event of an
object becoming trapped. The anti-trap protection device can be a
separate device or be integrated functionally into existing control
circuits, e.g. in the central control circuit or in a control board
or a lift board.
[0031] It is useful for the anti-trap protection function or device
to only be activated if a setpoint movement value, especially a
setpoint speed, of the door is reached, which reduces the danger of
a false triggering of anti-trap protection.
[0032] To protect the object that has become trapped in the door, a
maximum force time curve is not exceeded by the door. Trapping `at`
the door includes an object being trapped between the door and an
outside limit, e.g. the work surface, and also becoming trapped
between door and muffle frame or housing. Different force time
curves are provided for the two cases.
[0033] It is especially useful, when the door is being closed, for
at least one end switch to be present, which is arranged in the
area between muffle opening or frame and door, with an activation
of the at least one end switch deactivating the anti-trap device or
the anti-trap protection, i.e. stopping protective measures. This
end switch typically switches at an opening distance of 4-9 mm,
which is so small that objects can no longer become trapped. On the
other hand this ensures that there is no undesired reversing of the
door while it is closing. On activation of the at least one end
switch the door is pushed with a defined force--and no longer
speed-controlled--onto the muffle opening. It is still advantageous
however for a threshold-activated anti-trap protection system--i.e.
speed-dependent--to remain active.
[0034] The speed measurement device can however also be used for
other purposes, such as setting the speed of movement of the door.
This alone is not yet known nor is it suggested.
[0035] The invention is especially for high-level cooking
appliances, in which the muffle opening is a floor-side muffle
opening and the door is a base unit door which preferably moves in
a linear manner.
[0036] The invention will be explained in detail below with
reference to the enclosed schematic figures. The figures show:
[0037] FIG. 1 a perspective view of a high-level cooking appliance
mounted on a wall with lowered base unit door;
[0038] FIG. 2 a perspective view of the high-level cooking
appliance with closed base unit door;
[0039] FIG. 3 a perspective view of a housing of the high-level
cooking appliance without the base unit door;
[0040] FIG. 4 a schematic side view in cross-section along the line
I-I from FIG. 1 of the wall-mounted high-level cooking appliance
with lowered base unit door;
[0041] FIG. 5 a front view of a further embodiment of a high-level
cooking appliance;
[0042] FIG. 6 to 11 diagrams of displacement movements of a base
unit door under different general conditions;
[0043] FIGS. 12 and 13 force time profile curves for a base unit
door; and
[0044] FIG. 14 a diagram of a preferred displacement movement when
a thin object becomes trapped between a base unit door and a
muffle.
[0045] FIG. 1 shows a high-level cooking appliance with a housing
1. The rear of the housing 1 is mounted on a wall 2 in the manner
of a wall-mounted cupboard. A cooking compartment 3, which can be
checked via a viewing window 4 set into the front of the housing 1,
is defined in the housing 1. It can be seen from FIG. 4 that the
cooking compartment 3 is delimited by a muffle 5, which is provided
by a heat-insulating jacket not shown in the figure, and that the
muffle 5 features a muffle opening 6 on the floor side. The muffle
opening 6 can be closed by a base unit door 7. FIG. 1 shows the
base unit door 7 in a lowered position, in which its lower side is
in contact with a work surface 8 of a kitchen unit. To close off
the cooking compartment 3, the base unit door 7 should be moved
into the position shown in FIG. 2 known as the "zero position". To
adjust the position of the base unit door 7 the high-level cooking
appliance has a drive apparatus 9, 10. The drive apparatus 9, 10
has a drive motor 9, shown in FIGS. 1, 2 and 4 by the dashed
outline, which is arranged between the muffle 5 and an outer wall
of the housing 1. The drive motor 9 is arranged in the area of the
rear of the housing 1 and, as shown in FIG. 1 or 4, is actively
connected to a pair of lifting elements 10, which are connected to
the base unit door 7. In this case, as depicted in the schematic
side view shown in FIG. 4, each lifting element 10 is designed as
an L-shaped support, of which the vertical arm extends downwards
from the housing-side drive motor 9. To position the base unit door
7 the drive motor 9 can be actuated with the aid of a control panel
12 and a control switch 13 which is arranged as shown in FIGS. 1
and 2 on the front of the base unit door 7. As shown in FIG. 4, the
control circuit 13 is located behind the control panel 12 within
the base unit door 7. The control circuit 13, which consists here
of a number of circuit boards in different locations and performing
different functions, and communicating via a central communication
bus, represents a central control unit for appliance operation and
controls and/or regulates for example heating up, a movement of the
base unit door 3, implementation of user entries, an illumination,
anti-trap protection, timing of the heating elements 16, 17, 18, 22
and much more besides.
[0046] It can be seen from FIG. 1 that an upper side of the base
unit door 7 features a cooking zone 15. Almost the entire surface
of the cooking zone 15 is taken up by heating elements 16, 17, 18
which are shown as dashed outlines in FIG. 1. In FIG. 1 the heating
elements 16, 17 are two separate different-sized hotplate elements,
whereas heating element 18 is a radiant heating element provided
between the two hotplate heating elements 16, 17 which practically
surrounds the hotplate heating elements 16, 17. Hotplate heating
elements 16, 17 define associated heating zones or heating areas
for the user; the hotplate heating elements 16, 17 together with
the radiant heating elements 18 define a lower heating zone. The
zones can be shown by a suitable decor on the surface. Heating
elements 16, 17, 18 can each be activated via the control circuit
13.
[0047] In the exemplary embodiment shown the heating elements 16,
17, 18 are embodied as radiant heating elements which are covered
by a glass ceramic plate 19. The glass ceramic plate 19 has
approximately the same dimensions as the upper side of the base
unit door 7. The glass ceramic plate 19 is also equipped with
installation openings (not shown), through which sockets for
holding holder elements 20 for pot supports 21 extend, as shown in
FIG. 4. Instead of a glass ceramic plate 19 other--preferably
fast-response--covers can also be used, e.g. a thin metal
sheet.
[0048] With the aid of a control knob provided in the control panel
12 the high-level cooking appliance can be switched to a hotplate
or a bottom heat operating mode, which will be explained below.
[0049] In the hotplate operating mode the hotplate heating elements
16, 17 can be activated individually by means of control elements
11, which are provided in the control panel 12, via the control
circuit 13, whereas the radiant heating element 18 remains
inoperative. The hotplate operating mode can be executed with the
base unit door 7 lowered as shown in FIG. 1. It can however also be
operated in a closed cooking space 3 with a raised base unit door 7
in an energy saving function.
[0050] In the bottom heat operating mode, not only the hotplate
heating elements 16, 17 but also the radiant heating element 18 is
activated by the control circuit 13.
[0051] In order to achieve the most even possible browning profile
of the food being cooked during bottom heat operation, it is of
decisive importance for the cooking zone 15 providing the bottom
heat to have an even distribution of the heat power output over the
surface of the cooking zone 15, although the heating elements 16,
17, 18 have different rated outputs. Preferably the heating
elements 16, 17, 18 are thus not switched on permanently by the
control circuit 13 but the power supply to the heating elements 16,
17, 18 is timed. In this case the different levels of rated heating
power of the heating elements 16, 17, 18 are reduced so that the
heating elements 16, 17, 18 create an even distribution of the
heating power output over the surface of the cooking zone 15.
[0052] FIG. 4 is a schematic diagram of the position of a fan 23,
for creating air circulation for example in a hot air mode or for
supplying fresh air. In addition an overhead heating element 22
mounted on an upper side of the muffle 5 is provided which can be
embodied with a single circuit or with multiple circuits, e.g. with
an inner and an outer ring. Further heating elements--not shown
here for reasons of clarity--such as a ring heating element between
the rear wall of the housing 1 and the muffle can also be present
here. Through the control circuit 13 the different operating modes
such as overhead heating, hot air heating or rapid heating up mode
can also be set for example by the corresponding switching on and
switching off of the heating output of the heating element 16, 17,
18, 22, if necessary with activation of the fan 23. The heat power
can be set by suitable timing. In addition the cooking zone 15 can
also be of a different design, e.g. with or without an extended
cooking zone, as a pure--single or multi-circuit heat retention
zone without cooking areas and so forth. The housing 1 has a seal
24 against the base unit door 7.
[0053] The control panel 12 is primarily arranged on the front of
the base unit door 7. Other alternative arrangements are also
conceivable, e.g. on the front of the housing 1, divided up into
different subpanels and/or partly on side surfaces of the cooking
appliance. Further embodiments are possible. The design of the
control elements 11 is not restricted and can for example include
control knobs, rocker switches, pushbuttons and foil switches which
include display elements 14, e.g. LED, LCD and/or touchscreen
displays.
[0054] A front view of a high-level cooking appliance is shown
schematically and not true-to-scale in FIG. 5, in which the base
unit door 7 is open and in contact with the work surface 8. The
closed state is shown by a dotted outline.
[0055] In this embodiment there are two movement control panels 25
on the front side of the permanently attached housing 1. Each
movement control panel includes two press buttons, namely an upper
CLOSE button 25a for a base unit door 7 moving upwards in the
closing direction and a lower OPEN button 25b for a base unit door
7 moving downwards in the opening direction. With no automatic mode
the base unit door 7 only moves upwards where possible with a
continuous simultaneous pressure on the CLOSE buttons 25a of the
two movement control panels 25; the base unit door 7 also only
moves downwards, where possible, with a continuous simultaneous
pressure on the OPEN buttons 25b of the two movement control panels
(manual operation). Since in manual operation the user has to take
greater care during operation and in addition both hands are used
for this operation, anti-trap protection is then only optional. In
an alternate embodiment the movement control panels 26 are
accommodated on opposite outer sides of the housing 1 with the
corresponding CLOSE buttons 26a and OPEN buttons 26b, as shown by
the dotted outline.
[0056] The control circuit 13 indicated by a dashed outline, which
is located inside the base unit door behind the control panel 1,
switches the drive motor 9 so that the base unit door 7 starts to
move smoothly, i.e. not abruptly by simply starting the drive motor
9, but by using a defined ramp.
[0057] The control circuit 13 in this exemplary embodiment includes
a memory unit 27 for storing at least one target or movement
position P0, PE, P1, P2, PZ of the base unit door 7, preferably
with volatile memory chips, e.g. DRAMs. If a target position P0,
P1, P2, PZ is stored, the base unit door can move after actuation
of one of the buttons 25a, 25b or 26a, 26b on the movement control
panels 25 or 26 in the direction set automatically until such time
as the next target position is reached or one of the buttons 25a,
25b or 26a, 26b is actuated once more (automatic mode). In this
exemplary embodiment the lowest target position PZ corresponds to
the maximum opening, the (zero) position P0 to the closed state,
and P1 and P2 to freely-selectable intermediate positions. Once the
last target position for a direction has been reached in manual
operation the door must be moved beyond this position if this is
possible (meaning that the last end positions do not correspond to
a maximum opened or the closed end state). In a similar manner,
when no target position is stored for a direction--which for
example would be the case for an upwards movement into the closed
position, if only PZ is stored, but not P0, P1, P2--the door must
be moved in this direction in manual mode. if no target position is
stored, e.g. with a new installation or after a power
disconnection, no automatic mode is possible. If the base unit door
7 is moved in automatic mode an anti-trap protection is preferably
activated.
[0058] Automatic mode and manual mode are not mutually exclusive:
Continuous pressure on the movement control panel or panels 25, 26
causes the base unit door 7 to move in manual operation even if a
target position were able to be moved to in this direction. In this
case for example a maximum actuation time of the movement control
panels 25 or 25 or the associated buttons 26a, 26b or 26a, 26b
respectively can be defined for activation of automatic mode, e.g.
0.4 seconds.
[0059] A target position P0, P1, P2, PZ can be any position of the
base unit door 7 between and including the zero position P0 and the
maximum opening position PZ. The maximum stored opening position PZ
does not however have to be the position at which the door is
resting on the work surface 8. The target position P0, P1, P2, PZ
can be stored with the base unit door 7 at the desired target
position P0, P1, P2, PZ, by for example actuating an actuation
button 28 in the control panel 12 for a number seconds (e.g. a
period of two seconds). Existing optical and/or acoustic signal
generators which output appropriate signals after a target position
has been stored are omitted from the diagram to improve its
clarity. Moving the door to the desired target position P0, P1, P2,
PZ to be set is undertaken for example by--in this exemplary
embodiment--two-handed operation of the movement control panels 25
or 26 and manual movement to this position.
[0060] Just one, or as shown in this exemplary embodiment, a number
of target positions P0, P1, P2, PZ, can be stored in the memory
unit 27. With a number of target positions P0, P1, P2, PZ, these
positions can be moved to in turn by actuating the corresponding
movement buttons 25a, 25b or 26a, 26b. The number of target
positions P0, P1, P2, PZ enables the high-level cooking appliance
to be adapted conveniently to the desired operating height of a
number of users. The target position(s) are advantageously able to
be deleted and/or overwritten. In one embodiment for example only
one target position is able to be stored in the open state whereas
the zero position P0 is automatically detected and the door is able
to be moved to this position automatically. Alternately the zero
position P0 must be stored to enable the door to be moved there
automatically.
[0061] It is especially advantageous for ergonomic use if the
target positions or a target position P1, P2, PZ opens the base
unit door 7 at least appr. 400 mm to appr. 540 mm (i.e. P1-P0,
P2-P0, PZ-P0.gtoreq.40 cm to 54 cm). With this opening dimension
the food supports 21 can be easily placed into their holder
elements 20. In this case it is useful for the viewing window to be
mounted at about the eye level of the user or slightly below, e.g.
using a template which indicates the dimensions of the cooking
appliance.
[0062] Not shown in the drawing is an existing uninterruptible
power supply for bridging a power failure of around 1 to 3 seconds,
preferably of around 1.5 seconds.
[0063] The drive motor 9 from FIG. 1 has at least one sensor unit
31, 32 on a motor shaft 30, if nec. arranged in front of or behind
a gear, in order to measure a movement path or a position and/or a
speed of the base unit door 7. The sensor unit can for example also
include one or more induction, Hall, opto, OFW sensors and so
forth. In this case, for simple measurement of the distance and
speed, two (part) Hall elements offset by 180.degree.--i.e.
opposite each other--are accommodated on the motor shaft 30, and a
Hall measurement recorder 32 is fixed permanently at a distance in
this area of the motor shaft. if a Hall element 31 then moves past
the measurement recorder 32 as the motor shaft 30 rotates, a
measurement or sensor signal is created which is a good
approximation of a digital signal. With (not necessarily) two Hall
elements, two signals are thus output for one rotation of the motor
shaft 30. By evaluating the timing of the signals, e.g. their time
difference, the speed vL of the base unit door 7 can be determined,
for example using comparison tables or a conversion in real time in
the control circuit 13. By addition or subtraction of the
measurement signals a movement path or a position of the base unit
door 7 can be determined.
[0064] A speed regulator can for example implement the speed via a
PWM-controlled power semiconductor.
[0065] For determining the zero position the path measurement is
automatically newly synchronized in the zero position P0 of the
base unit door 7 for each movement to this position, so that for
example an error in a sensor signal output or detection does not
have any effect.
[0066] The drive motor 9 can be operated by actuating the two
movement control panels 25 or 26 even with the main switch 29
switched off.
[0067] Instead of two separate switches per movement panel 25, 26,
a single switch per movement panel is also possible, e.g. a rocker
switch with a neutral position which only switches under pressure.
Other forms are also possible. The type and arrangement of the
control elements 28, 29 of the control panel 12 is also not
restricted.
[0068] The arrangement and sub-division of the control circuit 13
in this case is flexible and not restricted, meaning that it can
also consist of a number of circuit boards e.g. a display circuit
board, a control circuit board and a lift circuit board which are
in separate locations.
[0069] A 4 mm opening dimension for example can be detected by end
switches 33, which on actuation deactivate an anti-trap protection.
It is possible however for the anti-trap protection to be
deactivated by counting pulses of the sensor signals when a count
is reached, which corresponds to a closure dimension of 8.6 mm for
example. The anti-trap protection is deactivated in this case
independently of such end switches 33.
[0070] Alternately only anti-trap protection measures are
deactivated that do not operate with threshold values, e.g.
mechanical switches, especially anti-trap protection mechanisms not
using a movement parameter of the door.
[0071] The high-level cooking appliance can also be embodied
without a memory unit 27, with no automatic mode then being
possible. This can be useful for increased operator safety, e.g.
for anti-trap protection.
[0072] FIG. 6 shows a diagram, not drawn to scale of a graph of the
speed of movement vL of the base unit door 7 in mm/s plotted
against the position of the base unit door in mm from the zero
position P0 for a movement of the base unit door 7 from the closed
state with P0=0 mm to PZ=maximum opening of 530 mm in this case in
manual movement mode (i.e. not moved automatically), as well as,
indicated by the dotted-line arrow, the displacement movement being
stopped between P0 and PZ. The curve is executed in the direction
of the arrow, i.e. from right to left. The arrows pointing
downwards above the curve indicate actuations of the control panel
12.
[0073] The downwards displacement movement of the base unit door 7
begins with two-handed activation of the movement switch panels 25,
26 or of the OPEN switches 25b or 26b, as indicated by the upper
left vertical arrow. The control circuit 13 regulates the drive
motor 9 so that the base unit door 7 is slowed smoothly, i.e. with
a defined ramp R1, to its required speed of here vL=50 mm/s. The
ramp R1 is linear here. The drive motor 9 is thus not simply
switched on.
[0074] The drive displacement movement is also independent of the
load, especially independent of the loading of the base unit door 7
or of changed frictional conditions of the mechanism. An input
variable for this can be the speed of the drive motor 9 which can
for example be measured by Hall sensors.
[0075] After reaching the required speed of vL=50 mm/s the base
unit door 7 moves constantly downwards until it approaches the
maximum opening PZ which is defined by the constructionally
predetermined maximum movement of the base unit door 7 or by
reaching the work surface 8. In this figure it is assumed that the
maximum opening PZ dictated by the construction is reached. In this
case the control circuit 13 detects this approach and brakes the
base unit door 7 smoothly automatically, i.e. with a defined ramp
R2, down to PZ. Both ramps R1 and R2 can have other slopes or
shapes. The approach to the base plate can be detected by the end
switch 33 and/or by monitoring the movement path.
[0076] If one or both of the movement switches 25b, 26b is
released, as indicated by the upper vertical arrow, the base unit
door 7 stops abruptly without any ramp, as indicated by the
dotted-line arrow. Thus the door starts to move smoothly in this
case but, --except where it reaches the end position--it is stopped
abruptly.
[0077] The cooking compartment 3 is not opened, the base unit door
7 is thus not moved from the zero position P0, if an opening
protection system is active, if for example a specific temperature
in the cooking compartment e.g. 425.degree. C. or 600.degree. F.,
is exceeded or if a child lock is activated.
[0078] FIG. 7 shows a diagram similar to that depicted in FIG. 6,
also not drawn to scale, for a movement of the base unit door 7
from the closed state to a stored position P1=476 mm in automatic
movement mode.
[0079] In this case the base unit door 7 begins to move
automatically to position P1 by brief activation of the OPEN switch
25b or. 26b, as indicated by the upper right-hand vertical arrow.
In this case too the base unit door 7 is started up smoothly
(right-hand ramp) and braked automatically (left-hand ramp). In
this embodiment a choice can be made in automatic mode between two
fixed setpoint speeds, namely 75 mm/s (dashed line) and 50 mm/s
(solid line), with the slower speed being better for older users in
particular. The lower speed level is preset ex-works for example.
More than two speed levels or setpoint speeds can also be provided;
A free choice of setpoint speed(s) by the user is also conceivable.
Expediently it is also possible to switch at least between two
speed levels of 50 mm/s and 65 mm/s, e.g. during appliance
initialization.
[0080] FIG. 8 shows a diagram, not drawn to scale, for moving the
bottom door 7 from the maximum opening position PZ to the zero
position P0, i.e. in the closed state, in manual operation.
[0081] The upwards displacement movement of the base unit door 7
begins with two-handed activation of the CLOSE switches 25a or 26a,
as indicated by the upper left vertical arrow. The control circuit
13 regulates the drive motor 9 so that the base unit door 7 is
moved smoothly from PZ up to its setpoint speed of vL=50 mm/s, and
then moved constantly at this setpoint speed (to the right).
[0082] The control circuit 13 detects an approach to the zero
position P0 and brakes the door 7 smoothly in good time beforehand.
Instead however of now moving downwards by means of the linear ramp
directly to the zero position P0, 4 mm before the zero position P0
the speed-dependent control switches over to control with a defined
voltage, i.e. by supplying the motor 9 with a corresponding
voltage. This allows a maximum force developed during blocking of
the drive motor 9 to be set. This voltage differs in accordance
with the previous history of the movement (loading, friction
conditions etc.). The 4 mm opening dimension is detected via the
distance measurement or in addition or as an alternative via the
end switches 33. Anti-trap protection can also be dispensed with in
the area from P0 to P0+4 mm.
[0083] If, as in FIG. 6, one or both of the movement switches 25b,
26b is released, as indicated by the upper right-hand vertical
arrow, the base unit door 7 stops abruptly without a ramp, as
indicated by the dotted arrow.
[0084] FIG. 9 shows a diagram, not drawn to scale, for a movement
of the base unit door 7 from a stored position P1=476 mm into the
closed state P0 in automatic movement mode. By contrast with the
manual movement mode shown in FIG. 8, only one of switches 25a, 26a
now needs to be briefly actuated, as indicated by the upper
horizontal arrow. The base unit door 7 then moves as in FIG. 7, but
in the other direction. When it approaches the zero position P0, as
with the situation from FIG. 8, the braking ramp switches for the
last 4 mm opening from a speed-controlled state to a load or
closing force-controlled state.
[0085] FIG. 10 shows a diagram similar to FIG. 8, in which trapping
now occurs at a setpoint speed of vL=50 mm/s, as indicated by the
upper vertical arrow. If an object, for example a hand or a pot
etc., becomes trapped between the base unit door 7 and the housing
1, the speed of the base unit door 7 drops since the object is
hindering further movement. The speed of lift is monitored here for
example through evaluation of the sensor signals of the motor
shaft, with the time between the measuring signals or impulses
being evaluated for example. Only in the second instance is the
motor current monitored, which is a somewhat slower method. In
particular the force able to be exerted by the motor 9 for movement
is restricted to avoid accidents caused by the object being trapped
too tightly (see also FIGS. 12 and 13). The deviation from the
setpoint speed is detected by the control circuit 13, e.g. through
a variation in the speed or a change in the speed over time. The
base unit door then reverses so that the object can be removed; an
acoustic warning signal is also issued if necessary. Thereafter the
base unit door 7 only starts to move again after the corresponding
movement keypad 25, 26 is pressed again.
[0086] So that anti-trapping is not triggered incorrectly, by a
changed loading for example or a change in the movement
characteristics of the mechanism, the anti-trap protection may only
be activated if the base unit door 7 has reached its setpoint speed
(if a movement key 25a, 25b, 26a, 26b is released beforehand, the
base unit door 7 comes to a halt immediately), and secondly a
number of sensor signals may be evaluated, for example
averaged.
[0087] FIG. 11 shows the operation of anti-trapping (upper vertical
arrow) during an opening movement of the base unit door 7 in
automatic mode to a target position P1, in which an object is
trapped between the lower side of the base unit door 7 and the work
surface 8. In this case detection of the trapped object can be
undertaken via two redundant end switches, which detect
an--especially uneven--relief of the load on the base unit door 7,
at which point the drive motor 9 reverses. The maximum allowed
force time profile (see FIGS. 12 and 13) is not exceeded in this
case.
[0088] FIG. 12 shows a maximum force F in N able to be applied to
the base unit door 7 in the event of trapping when the door is
moving in a closing direction (i.e. upwards) plotted against the
elapsed time t in s as a first force time profile FT1.
[0089] If trapping occurs when t=0 s the possible closing force is
limited to 100 N, corresponding to appr. 10 kg, for 5 s. This is
sensible for example if the motor 9 is regulated upwards by the
control device 13 to maintain the required speed. This especially
ensures that parts of the body will not be injured. If the base
unit door is accelerated for 5 s with (maximum) 100 N, the maximum
force applicable drops further to 25 N, e.g. for 5 seconds.
Subsequently this force level can be maintained or reduced further
to 0 N for example. It should be stressed that this force time
profile FT1 only specifies the maximum applicable force, and the
actually applied force generally lies below this, e.g. if the
trapping is detected by the control device 13, and the base unit
door 7 is reversed accordingly after t=0.5 s, after which the
applied force of 100 N drops to 0 N for example.
[0090] The maximum force threshold value of 100 N can also apply
for further movement situations.
[0091] FIG. 13 shows a maximum force F in N able to be applied to
the base unit door 7 in the event of trapping when the door is
moving in an opening direction (i.e. downwards) plotted against the
elapsed time t in s as a second force time profile FT2. Here the
drive motor 9 in a first block of t=[0 s; 0.5 s] can apply up to
400 N to the base unit door 7, then for t=[0.5 s; 5 s] 150 N and
then 25 N.
[0092] Naturally the time intervals and force threshold values of
the force time profiles FT1, FT2 are adapted to the structure and
further peripheral conditions.
[0093] FIG. 14 shows a typical flowchart, in which a speed vL with
which the door 7 is moved is plotted against a position P at a
particular moment. The speeds specified in millimeters per second
mm/s or the heights specified in millimeters are however to be seen
purely as examples.
[0094] Starting from an end position PZ, at which the door 7 is
stationary, the door 7 is accelerated by the drive motor 9 until it
reaches a lower intermediate position P2 and/or a required speed
vR. From the lower intermediate position P2, the door 7 is moved at
a constant speed upwards until it reaches a further, upper
intermediate position P1. As from this upper intermediate position
P1 the speed is reduced until a zero position P0 is reached which
corresponds to a closed state, so that a braking speed curve again
assumes a ramp shape.
[0095] Optionally, while the door 7 is moving upwards, a method for
monitoring a trapping state can be activated, with such a method
especially in the case of pure speed monitoring on switchover to
braking mode, i.e. especially from reaching the upper intermediate
position P1, being deactivated in accordance with a typical
embodiment. In accordance with another typical embodiment such
monitoring of a trapping state is deactivated only after reaching a
higher switchover position PS or is even not deactivated at all.
The switchover position PS can for example be detected by the
reaching of an end switch 33 or the detection of a predetermined
approach state of the door 7 to the muffle 5 as a result of an
accumulated number of Hall impulses.
[0096] In particular there can be provision for a switchover
between a anti-trap protection monitoring mode and a closing mode
to be undertaken, with for example the end switches 33 serving
during the initial upwards movement of the door 7 for monitoring
anti-trap protection while the same end switches 33 serve during
the final approach of the door 7 to the muffle 5 for closure state
monitoring in order to monitor a safe a firm closure of the door 7.
With such a switchover in particular the switchover expediently
occurs a little way before the zero position P0 is reached. In
particular the switchover is undertaken appr. 4-10 mm before the
zero position P0 is reached.
[0097] With such an approach of the door 7 to the muffle 5 or to a
flange fitted to the lower side of the muffle, trapping of usual
objects used in the household can be excluded. However there is the
danger of a thin child's finger, a pin or similar still being able
to penetrate into a narrow gap of this type, which could lead to
the child's finger being squashed and seriously injured.
[0098] Preferably an additional or alternate method for monitoring
a trapping state is activated, which however can also be activated
during the remaining upwards movement sequence. In this method the
cooking appliance is equipped with a functionality which detects a
trapping state through a threshold value which depends on a
displacement movement, especially a speed of the door 7.
[0099] The speed falling below a minimum (threshold value) vS
and/or the increase in the duration of measuring signals of a
Hall-element 31, i.e. a change in a differential speed, is
preferably used as a threshold value here. However the monitoring
of a motor current or of power drawn by the motor is accordingly
also able to be used as a threshold value.
[0100] In the execution sequence shown the door 7 approaches the
zero position P0 with the speed of a braking movement. As can be
seen from the enlarged section of FIG. 14, in the last closing
section shortly before the zero position P0 is reached, an object
gets between the door 7 and the muffle 5 and causes an increasing
speed reduction, which is shown as a reducing trapping speed
curve.
[0101] By contrast with a hard body, a partly elastic body such as
especially a child's finger does not cause an abrupt stop reducing
the speed to a value of zero when it becomes trapped, but initially
only a reduced slowdown in the speed. The undershooting of the
minimum speed vS, which is predefined for this section and/or the
increase in the differential speed .DELTA.vS or duration of
measurement pulses of the Hall elements 31 which are predefined for
this section can be detected as a criterion.
[0102] After the detection of a trapping state the speed of the
door 7 is preferably reduced to zero and subsequently briefly
increased in the opposite direction. During a reset speed curve v2
depicted and a subsequent renewed braking speed curve v3, the door
7 is preferably moved a little away from the muffle 5 by an opening
distance s, so that the trapped object can be removed.
[0103] Preferably a measuring signal of Hall element is used for
such monitoring of the trapping state in the remaining opening
distance s, which monitors a rotation of a drive shaft between the
drive motor 9 and a lifting element 10 for raising the door 7.
However other signal receivers can also be used which monitor an
instantaneous distance of the door 7 from the muffle 5 directly by
means of optical or mechanical movement sensors, speed sensors or
acceleration sensors. A changing motor output, meaning a power
consumption of the drive motor 9, can also be included as a
measuring signal.
[0104] As well as the use of such a method of operation for
monitoring the movement of the door 7 during a final closure
operation, such a method can basically be used over the entire
movement path. Also especially possible is the use of such a method
in addition to the use of further methods for monitoring a trapping
state, if necessary also further methods based on hardware, i.e.
switches in particular.
LIST OF REFERENCE SYMBOLS
[0105] 1 Housing [0106] 2 Wall [0107] 3 Cooking compartment [0108]
4 Viewing window [0109] 5 Muffle [0110] 6 Muffle opening [0111] 7
Base unit door [0112] 8 Work surface [0113] 9 Drive motor [0114] 10
Lifting element [0115] 11 Control element [0116] 12 Control panel
[0117] 13 Control circuit [0118] 14 Display elements [0119] 15
Cooking zone [0120] 16 Hotplate heating elements [0121] 17 Hotplate
heating elements [0122] 18 Radiant heating elements [0123] 19 Glass
ceramic plate [0124] 20 Holder part [0125] 21 Food carrier [0126]
22 Overhead heating element [0127] 23 Fan [0128] 24 Seal [0129] 25
Movement control panel [0130] 25a Upwards movement switch [0131]
25b Downwards movement switch [0132] 26 Movement control panel
[0133] 26a Upwards movement switch [0134] 26b Downwards movement
switch [0135] 27 Memory unit [0136] 28 Actuation button [0137] 29
Main switch [0138] 30 Motor shaft [0139] 31 Hall element [0140] 32
Measuring sensor [0141] 33 End switch [0142] FT1 First force time
profile [0143] FT2 Second force time profile [0144] P0 Zero
position [0145] P1 Intermediate position [0146] P2 Intermediate
position [0147] PZ End position [0148] PS Switchover position
[0149] R1 Speed ramp [0150] R2 Speed ramp [0151] vL Speed of
movement of the base unit door [0152] vR Setpoint speed [0153] vS
Threshold speed [0154] v Permitted minimum speed [0155] .DELTA.v
Differential speed [0156] v2 Reset speed curve [0157] v3 Braking
speed curve [0158] s Opening path
* * * * *