U.S. patent application number 11/992275 was filed with the patent office on 2009-12-31 for cooking appliance.
Invention is credited to Ingo Bally, Kerstin Feldmann, Wolfgang Fuchs, Edmund Kuttalek, Maximilian Neuhauser, Klemens Roch, Wolfgang Schnell, Keller Traunreut, Gunter Zschau.
Application Number | 20090320821 11/992275 |
Document ID | / |
Family ID | 37547583 |
Filed Date | 2009-12-31 |
United States Patent
Application |
20090320821 |
Kind Code |
A1 |
Bally; Ingo ; et
al. |
December 31, 2009 |
Cooking Appliance
Abstract
A cooking appliance, in particular, a cooking appliance which is
mounted in an elevated manner. Said cooking appliance comprises at
least one muffle which is defined by a cooking chamber and which
comprises a muffle opening, a door which is used to close the
muffle opening and a drive motor which is used to displace the
door. The drive motor is equipped with a self-locking
transmission.
Inventors: |
Bally; Ingo; (Traunstein,
DE) ; Feldmann; Kerstin; (Bretten, DE) ;
Fuchs; Wolfgang; (Altenmarkt a.d. Alz, DE) ;
Traunreut; Keller; (Traunreut, DE) ; Kuttalek;
Edmund; (Grassau, DE) ; Neuhauser; Maximilian;
(Chieming/Egerer, DE) ; Roch; Klemens; (Trostberg,
DE) ; Schnell; Wolfgang; (Trostberg, DE) ;
Zschau; Gunter; (Traunwalchen, DE) |
Correspondence
Address: |
BSH HOME APPLIANCES CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
100 BOSCH BOULEVARD
NEW BERN
NC
28562
US
|
Family ID: |
37547583 |
Appl. No.: |
11/992275 |
Filed: |
September 12, 2006 |
PCT Filed: |
September 12, 2006 |
PCT NO: |
PCT/EP2006/066285 |
371 Date: |
July 20, 2009 |
Current U.S.
Class: |
126/198 |
Current CPC
Class: |
F24C 15/027
20130101 |
Class at
Publication: |
126/198 |
International
Class: |
F24C 15/02 20060101
F24C015/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 19, 2005 |
DE |
102005044695.7 |
Claims
1-7. (canceled)
8. A cooking appliance comprising: a cooking chamber; at least one
muffle which delimits the cooking chamber; the muffle having a
muffle opening; a door for closing the muffle opening; a drive
motor for moving the door; a self-locking transmission associated
with the drive motor.
9. The cooking appliance as claimed in claim 8 wherein the
self-locking transmission includes a worm transmission.
10. The cooking appliance as claimed in claim 8 wherein the
self-locking transmission has a transmission ratio ranging between
30:1 to 60:1.
11. The cooking appliance as claimed in claim 10 wherein the
self-locking transmission has a transmission ratio ranging between
40:1 and 50:1.
12. The cooking appliance as claimed in claim 11 wherein the
transmission ratio is 45:1.
13. The cooking appliance as claimed in claim 8 wherein the drive
motor is short circuited when the muffle opening is closed by the
door.
14. The cooking appliance as claimed in claim 8 wherein the cooking
appliance is a high-level cooking appliance; the muffle opening is
a floor-side muffle opening; and the door is a base door.
Description
[0001] The present invention relates to a cooking appliance,
especially a high-level cooking appliance with a muffle enclosing
at least one cooking chamber, with a muffle opening, a door which
is used to close the muffle opening and a drive motor which is used
to move the door.
[0002] Locking catches are already known as a method of locking for
cooking appliances with motor-driven doors. The disadvantage of
these locking catches is the space that they require.
[0003] The object of the present invention is to provide a cooking
appliance with a facility for secure and compact locking of the
door.
[0004] The present object is achieved by the cooking appliance with
the features of claim 1. Advantageous embodiments can be found
individually or in combination in the subclaims.
[0005] To this end the cooking appliance, especially a high-level
cooking appliance but also a cooking appliance with a motorized
oven carriage, is equipped with a drive motor and with a
self-locking transmission. The self-locking transmission enables,
in the closed state of the door, a mechanical pulling open of the
door against the motor to be rendered difficult to the extent where
the opening of the door can be safely prevented.
[0006] Advantageously the self-locking transmission is a worm
transmission.
[0007] It has proved useful, especially for a high-level cooking
appliance, for the self-locking transmission to have a transmission
ratio ranging from 30:1 to 60:1, especially ranging from 40:1 to
30:1, specifically 45:1. The base door of a high-level cooking
appliance would not move with a transmission ratio of 45:1, even
with a load of over 20 kg.
[0008] It is advantageous for self-locking for drive motor to be
short circuited in the closed state of the door since the opening
force must then be applied against the self-induction of the
motor.
[0009] The invention will be described in more detail below on the
basis of the exemplary embodiments shown in the enclosed figures.
The figures show:
[0010] FIG. 1 a perspective view of a high-level cooking appliance
mounted on a wall with its base door lowered down;
[0011] FIG. 2 a perspective view of the high-level cooking
appliance with its base door closed;
[0012] FIG. 3 a perspective view of a housing of the high-level
cooking appliance without the base door;
[0013] FIG. 4 a schematic side view in cross-section along the line
I-I from FIG. 1 of the high-level cooking appliance mounted on the
wall, with its base door lowered down;
[0014] FIG. 5 a further embodiment of a high-level cooking
appliance viewed from the front;
[0015] FIG. 6 a front view of the embodiment from FIG. 5 in the
closed state with a more precise description of the location of
individual housing elements;
[0016] FIG. 7 a view from above in cross-section of the embodiment
from FIG. 6;
[0017] FIG. 8 parts of the drive apparatus for a more precise
description;
[0018] FIG. 9 in a side view similar to that shown in FIG. 4 of a
further embodiment of the high-level cooking appliance;
[0019] FIG. 10 the embodiment of the cooking appliance according to
FIG. 9 in a cross-sectional front view;
[0020] FIG. 11 a section from FIG. 10 in greater detail;
[0021] FIG. 12 a further embodiment of the high-level cooking
appliance with emergency opening arrangement in a view similar to
that shown in FIG. 7.
[0022] For better presentation of the individual elements the
figures are not drawn to scale.
[0023] 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 chamber 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 chamber 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 door 7. FIG. 1 shows the base
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
chamber 3, the base door 7 should be moved into the position shown
in FIG. 2 known as the "zero position". To adjust the position of
the base 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 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 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 FIG. 1 and 2 on the front of the base door 7.
As shown in FIG. 4, the control circuit 13 is located behind the
control panel 12 within the base 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, movement of the base door 3, implementation of operator
input, an illumination, anti-trapping measures, timing of the
heating elements 16, 17, 18, 22 and much more besides.
[0024] It can be seen from FIG. 1 that an upper side of the base
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; Hotplate heating elements 16, 17, together with
radiant heating element 18, define a bottom heat zone. The zones
can be indicated by a suitable decor on the surface. Heating
elements 16, 17, 18 can each be activated via the control circuit
13.
[0025] 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
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.
[0026] 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.
[0027] 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 door 7 lowered as shown in FIG. 1. It can however also be
operated in a closed cooking space 3 with a raised base door 7 in
an energy saving function.
[0028] 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.
[0029] 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.
[0030] FIG. 3 shows a schematic diagram of the position of an air
recirculation bowl 23 with a recirculation motor and an assigned
annular heating element, e.g. for creating hot recirculated air in
hot air operation. The air recirculation bowl 23 open to the
cooking chamber 3 is typically separated from the latter by an
impact wall (not shown). 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. 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 door 7.
[0031] The control panel 12 is primarily arranged on the front of
the base 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.
[0032] A front view of a high-level cooking appliance is shown
schematically and not true-to-scale in FIG. 5, in which the base
door 7 is open and in contact with the work surface 8. The closed
state is shown by a dotted outline.
[0033] 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
CLOSED button 25a for a base door 7 moving upwards in the closing
direction and a lower OPEN button 25b for a base door 7 moving
downwards in the opening direction. With no automatic mode the base
door 7 only moves upwards with a continuous simultaneous pressure
on the CLOSE buttons 25a of the two movement control panels 25; the
base 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-trapping
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.
[0034] The control circuit 13 indicated by a dashed outline which
is located inside the base door behind the control panel 1,
switches the drive motor 9 so that the base door 7 starts to move
smoothly, i.e. not abruptly by simply starting the drive motor 9,
but by using a defined ramp.
[0035] The control circuit 13 in this exemplary embodiment includes
a memory unit 27 for storing at least one target or movement
position P0, P1, P2, PZ of the base door 7, preferably with
volatile memory chips, e.g. DRAMs. If a target position P0, P1, P2,
PZ is stored, the base 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 door 7 is moved in
automatic mode an anti-trapping protection is preferably
activated.
[0036] Automatic mode and manual mode are not mutually exclusive:
Continuous pressure on the movement control panel or panels 25, 26
causes the base 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 26 or the associated buttons 25a, 25b or 26a, 26b
respectively can be defined for activation of automatic mode, e.g.
0.4 seconds.
[0037] 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 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 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.
[0038] 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.
[0039] It is especially advantageous for ergonomic use if the
target positions or a target position P1, P2, PZ opens the base
door 7 at least appr. 400 mm to appr. 540 mm for (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.
[0040] 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.
[0041] 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 transmission, in order to measure a movement path or a position
and/or a speed of the base 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 path 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, 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 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 door 7 can be
determined.
[0042] A speed regulator can for example implement the speed via a
PWM-controlled power semiconductor.
[0043] For determining the zero position the path measurement is
automatically newly synchronized in the zero position P0 of the
base 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.
[0044] 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.
[0045] 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.
[0046] The arrangement and subdivision 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 at
separate locations.
[0047] A 4 mm opening dimension can be detected by end switches 33,
which on actuation deactivate an anti-trapping protection.
[0048] 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-trapping protection.
[0049] FIG. 6 shows a schematic diagram (not true to scale) viewed
from the front to illustrate the position of individual elements of
the housing 1 in the closed state, in which the base door 7 is
against the muffle 5 to close it and in doing so also closes off
the housing 1 optically. The housing 1 consists of an (inner)
housing body 34 (shown as a dashed line) and a housing cover or
panel 35, which surround the housing 34 at least at the front and
the side. The intermediate space 36 between housing body 34 and
housing cover 35 is embodied so that the cooling air can flow at
least partly through it. For this purpose lower ventilation
openings 37, e.g. ventilation slots, are provided in the housing
cover 35 which are mounted more deeply than the upper surface 38 of
the housing body 34, preferably in a region in the vicinity of the
muffle opening or of the lift floor 7. The ventilation openings 37
are made here on the underside of the housing cover 35; but can
also for example be present on its sides. One or more corresponding
upper ventilation openings 39, e.g. an exhaust slot, a located in
the upper part of the housing cover 35, specifically in its roof.
This enables a flow of air consisting of cooling air to be built up
through the intermediate space 36, typically from bottom to top of
which is then discharged through the roof.
[0050] The muffle (shown by a dotted outline) is mounted in the
housing body 34, with the associated intermediate space 40 being
clad with insulation material except for its front side. The muffle
5 is conversely embodied in a U-shape. To allow the operator to
look into the cooking chamber 3 a number of viewing windows 4 are
present, namely a first (inner) viewing window 41 directly covering
the muffle 5 (shown by a dotted outline) which thus at least partly
represents one wall of the muffle 5, furthermore a second (middle)
viewing window 42 held by the housing body 34 (also shown by a
dotted outline) and a third (outer) viewing window 43 in the
housing cover 35.
[0051] Optionally further intermediate windows can be inserted (not
shown) which are preferably attached to the housing body 34, or
fewer viewing windows 4 can be present e.g. only the inner and the
outer viewing window 41, 43. The ventilation slots 37, 39 can also
be installed in another arrangement and form.
[0052] FIG. 7 shows, in a view onto the housing I from above,
according to the section plane III-III from FIG. 6 (i.e. without
upper housing wall) a more detailed, not true-to-scale view of the
inside of the housing with different elements arranged within it.
This provides a good view of the spaces 36 between housing body 34
and housing cover 35, namely the side spaces 44, the front space 45
and the rear space 46. Because of the three viewing windows 41, 42,
43 the front space 45 is divided up vertically into a first front
space 45a between middle viewing window 42 and outer viewing window
43 and a second front space 45b between middle viewing window 42
and inner viewing window 41. Naturally the spaces do not have to be
empty but can feature different elements, such as lifting elements
10, brackets, breakthroughs, insulation, air guide elements such as
ventilation baffles, screws, struts etc., with not every space 36
also having to allow a significant cooling air stream.
[0053] The following are especially mounted on the housing body 34:
Electrical or electronic modules 47 such as the control circuit 13,
a drive apparatus 48 and a fan device 49.
[0054] The fan device 49 comprises at least one fan, which in this
embodiment is precisely one fan which sucks in air by means of two
inlet openings from two directions. A two-section fan is
advantageously used here in which additionally the exhaust air is
output at least essentially unmixed. Especially suitable is the
double radial fan 50 shown here which has two inlet openings lying
opposite one another and discharges the induced air to the side. In
this case the two induced air flows are essentially output sideways
in parallel to each other.
[0055] In the form of construction shown here an inlet opening of
the double radial fan 50 is connected to an induction channel 51
which covers the front space 45 at least partly from above and
thereby sucks in air during operation from below out of the lower
ventilation openings 37 through the front space 45. This means that
the front space 45 is cooled for improved operator safety, since
because of its viewing windows 4, 41-43 this space provides lower
heat insulation.
[0056] The other (rear) induction opening of the double radial fan
50 is open. Air is sucked in through this opening especially from
the side spaces 44 and the rear space 46 and flows over the upper
surface 38 to the fan 50. This means that the components arranged
on the upper surface also have a flow of air around them which
cools them. This is especially advantageous for the electronics
module 47.
[0057] The exhaust air of the fan 50 flows through an exhaust air
duct 52 to an upper air outlet 53, which blows the air out through
the ventilation opening(s) 39 from FIG. 6.
[0058] The drive apparatus 48 comprises a motor 9 attached
centrally on the surface 38 of the housing body 34 on which a guide
housing 54 rests. Two guide channels (not shown) run through the
guide housing 54. The guide housing 54 has a circular cutout for
introducing a pinion 55 of the motor 9. The guide channels lead
upwards past the sides of the cutout, so that ropes, cables etc.
located in the guide channels are made to engage with the pinion
55. Attached to the outer openings of the guide channels, i.e. at
four openings here, are guide tubes 56, which, together with the
guide channels, form continuous cable channels. The guide tubes 56
extend in this embodiment from the guide housing 54 to the edge of
the upper surface 38 into an area above the lifting elements 10 and
onwards over the edge down into the lifting elements 10.
[0059] Running in each of the two cable channels is a hoisting
cable as drive cable (not shown). The hoisting cable has a bendable
metal core and is wire-wrapped. One end of each hoisting cable is
fixed to the base door 7, the other is free. Since the two hoisting
cables engage with the pinion 55 on opposite sides, they are
displaced linearly by the rotation of the pinion 55 in opposite
directions. The hoisting cable drive can for example be obtained
from WEBASTO in Germany.
[0060] The guide tubes 56 are elastically deformable, e.g. formed
from die-cast aluminum. At least one load-bearing guide tube 56
(i.e. a guide tube 56 which guides a section of a hoisting cable
which is permanently connected directly or indirectly to the base
door 7; meaning that there is a load on this section of the
hoisting cable) rest on a support 57 with the support force
depending on the size of the load at the hoisting cable. In this
embodiment such a support 57 is provided for each load-bearing
guide tube 56. The supports 57 are essentially located at the edge
of the upper surface 38 of the housing body 34, so that the
length--of the "arm"--of the guide tube 56 able to be deflected
under load is large. This means that the load dependency of the
essentially perpendicular force exerted by the respective guide
tube 56 on the support 57 is as large as possible. The support
force depends for example on the loading of the base door 7 or its
placement on a support surface or an object. By measuring the
support force for example a protection against overloading of the
base door 7 or an anti-trapping protection can be implemented.
[0061] The length of the guide tubes 56 is at the discretion of the
designer and can be comparatively short or can extend as far as the
attachment of the hoisting cable to the base door 7 (in the closed
state).
[0062] To use the support of the hoisting cables for load
measurement the use of a guide tube 56, although advantageous for
reasons of smooth movement and friction, is however not absolutely
necessary. It is also possible to route the hoisting cables--or
cable or rope in general--freely over suitably positioned supports
(reaching over the edge of the surface). The supports are then
expediently embodied accordingly, e.g. made from a suitably hard
and/or slippery material, surface-treated or surface coated.
[0063] The use of a hoisting cable drive is also not mandatory, but
is advantageous because of the simple construction and assembly as
well the precise movement. Alternate drives include those with a
driven side drum etc. for example.
[0064] To describe the drive principle more precisely, FIG. 8 shows
a view from above of the guide housing 54 with guide tubes 56
joined to it, which form two separate guide channels, namely--in
this diagram--an upper and a lower guide channel. Running in each
of the guide channels 54, 56 is a hoisting cable 58, typically of
around one meter in length. The guide channels route the hoisting
cables 58 to a cutout in the guide housing 54, through which a
toothed wheel or pinion 55 driven by the drive motor projects. The
teeth of the pinion 55 engage with the winding wire of the
respective hoisting cable 58, which, as far as the pinion 55 is
concerned, forms a type of linear sequence of teeth.
[0065] When the pinion 55 is turned by the drive motor--in the
clockwise direction indicated by the solid arrows here--the upper
hoisting cable 58 is displaced linearly from left to right and the
lower cable 58 is moved by the same amount from right to left, as
indicated by the dashed arrows.
[0066] Since the hoisting cables 58 are permanently engaged with
the pinion 55 and are thereby permanently coupled to the drive
motor, an effective locking of the base door in the opening
direction can also be achieved, e.g. to protect against the door
being opened when the cooking chamber is hot, for example during
pyrolysis, or when the child lock is switched on. Previously a
mechanical locking has been used for locking which, depending on
specific parameters such as a threshold value temperature etc.,
typically closes the door by means of a locking latch. However this
type of locking can be dispensed with if the drive motor according
to reference character 9 from FIG. 7 for example drives the pinion
55 via a self-locking drive (not shown). If the drive motor is
switched off--which preferably occurs by switching off the power
and deactivating directional switches--to open the cooking chamber
or in general to move the base door, a mechanical force and an
induction force of the drive motor must be overcome. The force
applied to do this must be all the greater the greater the
transmission ratio of the drive is. For the embodiment shown a
transmission ratio in range of 30:1 to 60:1 has been shown to be a
good compromise between self-locking and speed of movement. In
particular a transmission ratio ranging from 40:1 to 50:1,
specifically of 45:1, is suitable. With a transmission ratio of 45
the base door could not be opened even with a load of more than 20
kg.
[0067] One of a number of possible forms of embodiment of the drive
is a worm drive. Other types of drive are known to the person
skilled in the art of mechanical engineering.
[0068] Obviously the transmission ratio is not restricted to this
range and can be adapted by the person skilled in the art for
example to the specifications of the drive motor used, the
mechanical friction of the actuating mechanism of the base door,
the type of drive (hoisting cable rope drum etc.), the weight and
the loading of the base door and much more besides.
[0069] FIG. 9 shows in a side view, similar to that shown in FIG.
4, a view of a further embodiment of the high-level cooking
appliance with a more precise description of the drive apparatus
from FIGS. 7 and 8. The drive motor 9, the guide housing 54, the
fan device 49 and the electronics module 47 are omitted to aid
clarity in the diagram. The other side of the cooking device is
constructed in a similar way.
[0070] The elastically-deformable guide tubes 56 can be seen which
rest at the top on the support 57 and are then routed bent
downwards into the lifting elements 10. The hoisting cables 58
emerge from the free openings of the guide tubes 56, namely at a
section of a hoisting cable 58 bearing a load on this side
(left-hand) which is connected via the attachment element 59 to the
lower telescopic bar 60 of the lift element 10 and thereby
indirectly to the base door 7. The other (right-hand) hoisting
cable 58 has a free end on this side. The other hoisting cable 58
is attached or is free respectively on the other side of the
cooking appliance. Through actuation of the drive motor the
hoisting cables 58, as described above, are displaced linearly and
lift the base door 7 up correspondingly or lower it down.
[0071] FIG. 10 shows the embodiment of the cooking appliance
depicted in FIG. 9 in a sectional view, from the front along the
section IV-IV from FIG. 9.
[0072] It can be seen that the hoisting cables 58 and the guide
tube 56 are diverted at the support 57 from the horizontal into the
vertical. On each of the supports 57 a (deflection) force is
therefore exerted by the respective load-bearing section of the
hoisting cables 58 via the elastically-deformable guide tubes 56
which essentially depends on the load on the load-bearing section
of the hoisting cable 58, including the weight of the base door 7
and the load on the door. In this diagram only the normal
components Fn1, Fn2 of the respective deflection force are
plotted.
[0073] By measuring the deflection force, especially the respective
normal force Fn1 or Fn2 on the corresponding support 57, an
overloading of the base door 7 or an instance of trapping can for
example be detected.
[0074] The overloading of the base door 7 is for example measurable
by a specific load threshold being undershot.
[0075] A case of trapping in the closing direction of movement of
the base door 7, i.e. mostly between base door 7 and housing, as
well as in the opening direction of the base door 7, i.e. at least
between a base door 7 and work surface, can for example be detected
if a difference between Fn1 and Fn2 becomes greater than a specific
set threshold value. Alternately time differences in the relieving
of the load between the two sides can be detected.
[0076] FIG. 11 shows in greater detail a section depicted by the
dashed line circle in FIG. 10.
[0077] Here the support 57 moves a switching lever 62 which
switches a switch 63 when the load is relieved. In this exemplary
embodiment it is only possible to detect a value falling below or
exceeding a load threshold value. Possible applications,
embodiments and measurement principles are described for this
process example in DE 102 28 140 A1 and DE 101 64 239 A1.
[0078] Alternately other load-measuring sensors are can be used
which measure forces acting on the support 57, especially but not
only, the normal force Fn. In these cases further evaluation
options for detecting the trapping can be used such as for example
a speed change of the load which may exceed a specific threshold
value or may deviate from a setpoint value (e.g. a speed of
movement or speed ramp) and which indicates the trapping in this
way.
[0079] FIG. 12 shows, like the diagram depicted in FIG. 7, a
further embodiment of the cooking appliance with an emergency
opening arrangement for moving the base door in the event of a
power outage at the cooking appliance or a failure of the drive
motor 9.
[0080] The drive motor 9 has a toothed wheel in the form of a
beveled wheel 65 at a power take-off 64 which is actively connected
to the motor shaft (not shown). In addition a fixed rotatably
supported shaft 66 is present on the end of which is a toothed
wheel in the form of a beveled wheel 67. The other end of the shaft
66 is embodied and arranged as an override unit or area 69 for
operation by the user. The shaft 66 is attached by two brackets 68
to the housing body 34 and in addition has a retaining element 70
in the form of the spring which in normal operation holds the shaft
66 in position with a retaining force Fr (indicated by the arrow),
in which the beveled wheel 67 of the shaft is decoupled from the
beveled wheel 65 of the drive motor 9. The shaft 66 has a hexagonal
cross section so that a control element, embodied as a crank or a
hexagonal key for example, is easily able to be placed over the end
embodied as the override unit 69 (not shown). In normal operation
the end embodied as the override unit 69 is concealed behind the
front panel or the front housing cover 35.
[0081] In emergency operation when the drive motor 9 can either no
longer be actuated via the control panel or the power to the entire
appliance has failed, the emergency opening arrangement still
allows the base door to be moved. To this end, in this embodiment
the front panel is first removed so that the user obtains access to
the override unit 69. The user then places a crank with a suitable
cutout onto the shaft 66 and pushes the shaft 66 back against the
retaining spring force Fr with its beveled wheel 67 into contact
with and thereby so that it engages with the beveled wheel 65 of
the drive motor 9. By subsequently turning the crank the drive
motor 9 and thereby by association the pinion 55 and the hoisting
cables are moved, which causes the base door 7 to be moved.
[0082] On return to normal operation the pressure is released from
the shaft 66, the crank is taken off and the front panel is put
back on.
[0083] The toothed or beveled wheel 65 can be directly attached to
the motor shaft. The shaft 66 can also be flexible. The operating
part can be permanently connected to the override unit 69 or the
shaft 66. The emergency opening arrangement can also be structured
so that the shaft is not decoupled during normal operation and thus
turns permanently as well. As well as a shaft any other device is
suitable which transfers mechanical forces without power, namely
from the override unit 69 or an operating part to the motor
shaft.
LIST OF REFERENCE SYMBOLS
[0084] 1 Housing
[0085] 2 Wall
[0086] 3 Cooking chamber
[0087] 4 Viewing window
[0088] 5 Muffle
[0089] 6 Muffle opening
[0090] 7 Base door
[0091] 8 Work surface
[0092] 9 Drive motor
[0093] 10 Lifting element
[0094] 11 Control element
[0095] 12 Control panel
[0096] 13 Control circuit
[0097] 14 Display elements
[0098] 15 Cooking zone
[0099] 16 Hotplate heating elements
[0100] 17 Hotplate heating elements
[0101] 18 Radiant heating elements
[0102] 19 Glass ceramic plate
[0103] 20 Holder part
[0104] 21 Food carrier
[0105] 22 Overhead heating element
[0106] 23 Fan
[0107] 24 Seal
[0108] 25 Movement control panel
[0109] 25a Upwards movement switch
[0110] 25b Downwards movement switch
[0111] 26 Movement control panel
[0112] 26a Upwards movement switch
[0113] 26b Downwards movement switch
[0114] 27 Memory unit
[0115] 28 Actuation button
[0116] 29 Main switch
[0117] 30 Motor shaft
[0118] 31 Retaining element
[0119] 32 Measuring sensor
[0120] 33 End switch
[0121] 34 Housing body
[0122] 35 Housing cover
[0123] 36 Space
[0124] 37 Lower ventilation openings
[0125] 38 Upper surface of the housing body (34)
[0126] 39 Upper ventilation opening
[0127] 40 Space
[0128] 41 First (inner) viewing window
[0129] 42 Second (middle) viewing window
[0130] 43 Third (outer) viewing window
[0131] 44 Side spaces
[0132] 45 Front space
[0133] 45a First front space
[0134] 45b Second front space
[0135] 46 Rear space
[0136] 47 Electrical or electronics module
[0137] 48 Drive apparatus
[0138] 49 Ventilation device
[0139] 50 Fan
[0140] 51 Induction channel
[0141] 52 Exhaust channel
[0142] 53 Air outlet
[0143] 54 Guide housing
[0144] 55 Toothed wheel
[0145] 56 Guide tubes
[0146] 57 Support
[0147] 58 Hoisting cables
[0148] 59 Lower telescopic bar
[0149] 60 Hoisting cable attachment
[0150] 61 Upper telescopic bar
[0151] 62 Switching lever
[0152] 63 Switch
[0153] 64 Housing power take-off
[0154] 65 Toothed wheel
[0155] 66 Shaft
[0156] 67 Toothed wheel
[0157] 68 Brackets
[0158] 69 Override unit
[0159] 70 Retaining element
[0160] Fn1 Normal force 1
[0161] Fn2 Normal force 2
[0162] Fr Retaining force
[0163] P0 Zero position
[0164] P1 Intermediate position
[0165] P2 Intermediate position
[0166] PZ End position
* * * * *