Note: Descriptions are shown in the official language in which they were submitted.
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hri~roved User Interface for Cooking Appliances
This application claims the benefit of U.S. Provisional Application No.
60/286,359, filed on April 26, 2001, and U.S. Provisional Application No.
60/286,339,
filed on April 26, 2001.
Field of the Invention
The present invention relates in general to cooking appliances. In particular,
the
present invention relates to an interface for cooking appliances.
Background of the Invention
Heaters in cooling appliances, such as glass-ceramic cooktops, often have the
radiant heater located underneath a piece of ceramic-glass or constructed such
that the
heating element is in direct contact with the cookware as in a conductive
system. The
heater or heaters are generally controlled with a known form of
electromechanical
regulator or some type of electronic control that cycles the heater on and off
using an
adjustable time base technology. This technology mechanically accomplishes the
two
step on, one step off function, but will not communicate with electronic
controllers.
Another type of control alters the electrical supply wave form to change the
power
applied to the heaters.
One such control is an infrared touch control that uses reflected infrared
light as
the user interface. Another known user interface for an electronic control in
glass-ceramic
cooktops is the field effect sensor technology. This technology uses
electrostatic fields
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that emanates around a touch pad. When the user interrupts this field the
controller
interprets this as human actuation. The capacitance touch sensor is another
known input
to an electronic control for this application. One other input device that the
user may
interface with an electronic control is the membrane switch.
All of the above systems have their problems and limitation. The
electromechanical regulators axe time based controls that turn on the heaters
with full
power for a period of time and then off for a period of time. The shortest
cycle time they
can manage is anywhere from one to two minutes. This type of control gives
very poor
heat regulation, especially at the lower heat settings. The infrared touch
control has
problems of insensitive, incorrect or random switch actuation that can occur
due to a spill
on the cooktop surface or placing a pan or other items over or against the
touch pad. The
field-effect and capacitance touch sensors have problems with incorrect or
random switch
actuation due to RF and e-field interference. Moisture presents extreme
difficulties for
conventional capacitance sensors. Plastic membrane switches are very heat
sensitive and
present a problem due to varying texture and tactile feel. They often appear
wrinkled or
wavy, become dull with use and are difficult to color match with adjacent
panels and
substrates. The membrane edges also trap dirt, which can contaminate the
signal and
create cleaning problems. Presently, electronic controllers accomplish the
safety
agencies' two step on, one step off function by adding redundant circuitry.
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Summary
One embodiment of the present invention provides a cooking controller
assembly,
including a heating element, a push-to-turn rotary switch, and an electric
controller. The
heating element is coupled to the push-to-turn rotary switch and the electric
controller.
The push-to-turn rotary switch is manually pushed and turned to selectively
connect
power to the heating element. The electric controller is coupled to the push-
to-turn rotary
switch and the heating element, and electrically controls the power to the
heating element
in relation to the manual rotation of the push-to-turn rotary switch.
Brief Description of the Drawings
In the drawings, like reference numerals represent similar parts of the
illustrated
embodiments of the present invention throughout the several views and wherein:
FIGS. 1A, 1B, 1C, 1D, 1E, 1F, and 1G are cross-sectional views of an
embodiment of a switch assembly;
FIG. 2 is a perspective view of the switch assembly of FIG. 1, wherein the
components of the switch assembly are detached;
FIG. 3 is a rotational chart of one embodiment of a switch assembly;
FIG. 4 is a flow diagram of the switch assembly of FIG. 1; and
FIG. 5 is a block diagram of an embodiment of a cooking controller assembly.
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Detailed Description
One embodiment of a switching apparatus 100 (see FIGS. 1 and 2) allows a user
to interface with an electronic controller, which may energize an electric
heater from a
single alternating current voltage supply. The switch 100 may include two sets
of dry
contacts 125. One set 125 breaks the current to the heater and/or other device
being
controlled. A second set 125 of contacts energizes a warning light and/or
other signal
device for feedback to the user. The contacts 125 are activated by rotating a
switch shaft
105. The switch shaft 105 is coupled to a camshaft 110 that can open (see FIG.
1B) and
close the contacts 125, through cams 150, at predetermined angles of rotation.
The
contacts 125 can either open and close at the same angle of rotation and/or
can be set to
open and close at different angles in the rotation of the shaft.
One end of the switch shaft 105 can be fitted with a knob for ease of use. The
other end of the switch shaft 105 goes through the switch housing 115 and is
coupled to
the camshaft 110. The switch shaft 105 may slide into the camshaft 110. A
spring 120 is
placed inside the camshaft 110 and between the camshaft 1.10 and the switch
shaft 105.
This spring 120 applies a force on the switch shaft 105 to hold the shaft 105
in an
extended position. Appropriate stops are placed on the shafts to keep them
from coming
apart when the switch shaft 105 is in its extended position. Stops located in
the switch
housing 115 may not allow the shaft 105 to be rotated unless sufficient force
is applied to
the switch shaft 105. To activate the switch the user may first push the
switch shaft 105
inward a predetermined distance, with a predetermined amount of force to
rotate the shaft
105. To deactivate the switch the user rotates the shaft 1 OS back to the off
position. The
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internal spring 120 forces the switch shaft 105 back into the locked position.
This gives
the switch 100 a two step on, and one step off feature, required for safety
agency
approvals.
One end of the camshaft 110 is interconnected with the center contact of a
potentiometer 130 (see FIG. 2). When the camshaft 110 is rotated, the
resistance between
the output pins of the potentiometer 130 changes in relationship to the
angular position of
the shaft. The analog potentiometer 130 incorporated in the switch allows for
a variable
~~ output. The output may be used to interface the mechanical movement of the
potentiometer with a micro controller. This allows manual selection of anyone
of a
predetermined number of power settings for the heater or other device from the
power
supply (see FIG. 3).
The switch 100 may include a temporary stop spring 135. This spring 135
rotates
with the camshaft 110 and limits the rotation of the camshaft 110 at a
predetermined
point. This stop point alerts the end user that full power is applied to the
equipment being
controlled after the temporary stop is reached. A second condition can be
achieved by
applying additional rotational force to the shaft 110 to overcome the spring
tension of the
temporary stop spring 135. This allows the center tap of the potentiometer 130
to
complete its travel to its end stop position. When the applied force is
removed, the shaft
returns to the temporary stop position. This action can be used as a momentary
switch to
signal the micro controller to perform another function.
FIG. 4 illustrates another embodiment of a switch assembly. The switch
assembly
includes a shaft, a first switch S1 and a second switch S2, a potentiometer
130 including a
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first and a second terminal, and a controller. The first switch S 1 may
coupled to a first
device. The second switch S2 may be coupled to a second device. The first
device may
include a heating element 510, whereas the second device may include an
indicator S 15
such as, for example, a light (see FIG. 5). The shaft is coupled to the first
switch S1 and
the second switch S2, and may be manually pushed and turned (i) to a first
position to
selectively connect power, through the first switch, to the first device, and
(ii) to a second
position to selectively connect power, through the second switch, to the
second device.
The potentiometer 130 is be coupled to the shaft, and provides a variable
resistance
between the first and the second terminal in relation to the manual rotation
of the shaft
assembly. The controller is coupled to the potentiometer 130, and controls the
power to
the first device and/or the second device in relation to the variable
resistance between the
first and the second terminal of the potentiometer. The controller may include
an electric
controller 505 (e.g., a known electric controller). The electric controller
505 may then
electrically control the power to the first device and/or the second device.
In sum, the power contacts can be activated and deactivated at different
angles of
rotation of the shaft. This permits some event such as starting a cooling fan
to occur
before starting the next event such as energizing a heater. The potentiometer
addresses
the two step on and one step off function, required for safety agency
approval. The
potentiometer when used as an on/off switch can withstand the high current
requirements
when energizing and de-energizing a load such as a heater. The potentiometer
may
include a temporary stop in the travel of the wiper arm or center contact. The
switch may
include the ability to interface with an electronic power controller.
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One embodiment uses push to turn rotary switches as user control for an
electric
cooktop. The switches may interface with an electric controller which in turn
controls the
power to the electric heating elements. The user then has the familiar and
comfortable
' feel of a rotary switch while having the advantage of electronic cooking
control.
FIG. 5 illustrates the embodiment of the cooking controller assembly. The
cooking system may include a user interface that communicates with an
electronic
controller 505, which in turn modulates the power to the heater 510. The
interface may
include a push to turn rotary switch 100, which can be used to interface with
an electronic
heater controller 505. By incorporating, for example, a push to turn on rotary
switch, a
user can cook using state of the art electronic controls while having the
comfort and feel
of a rotary switch. The two step on and one step off function (required for
safety agency
approvals of the cooking appliance) does not require redundant circuits. This
mechanical
means of switching on and off the heating element power eliminates the
problems with
insensitive to touch, incorrect or random switch actuation that can occur due
to spills on
the cooktop surface or placing pans or other items over or against the touch
pad. No
incorrect or random switch actuation occurs due to RF and e-field
interference. Moisture
on the glass has no effect on the switch action. The interface switch includes
the ability to
supply an adjustable analog signal to the microcontroller 505. The
microcontroller 505 in
turn can control the power being supplied to the heating elements 510. This
allows the
user to control the temperature of the heating element 510 very precisely such
as, for
example, medium and low temperatures. The rotary switch 100 is mechanically
robust in
design and resistant to damage due to either mechanical abuse and exposure to
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chemicals.
The cooking controller assembly may include a heating element 510, a shaft
assembly, a switch, and an electric controller 505. The heating element 5I0 is
coupled to
the switch and the electric controller 505. The shaft assembly is coupled to
the switch,
and moved in a first direction and a second direction relative to the heating
element 510
to selectively connect, through the switch, power to the heating element 510.
The shaft
assembly may include a knob, which is turnable by hand. The switch may include
a push-
to-turn switch. The electric controller 505 is coupled to the switch and the
heating
element 510, and electrically controls the power to the heating element 510 in
relation to
the movement in the first direction and/or the second direction of the shaft
assembly. The
controller 505 may comprise one or more microprocessors, microcontrollers, or
other
arrays of logic elements. Also, the electronic controller 505 may include
Diehl's EU-PPS
Control, Diehl's ULCL Control, etc. The movement in the first direction and
the
movement in the second direction may be in the same direction. The power to
the heating
element may be supplied from a single alternating current voltage supply.
The foregoing presentation of the described embodiments is provided to enable
any person skilled in the art to make or use the present invention. Various
modifications
to these embodiments are possible, and the generic principles presented herein
may be
applied to other embodiments as well. As such, the present invention is not
intended to be
limited to the embodiments shown above, and/or any particular configuration of
structure
but rather is to be accorded the widest scope consistent with the principles
and novel
features disclosed in any fashion herein.
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