Note: Descriptions are shown in the official language in which they were submitted.
PCT
24875.8023 (40W01)
DUAL COIL ELECTRIC HEATING ELEMENT
BACKGROUND
[0001]
Electric heating elements convert electrical energy to heat energy. Stovetop
electric
heating elements are susceptible to overheating food and liquid thereby
creating hazards,
including fire hazards. In addition, manufacturers of stovetop electric
heating elements must
= conform to UL 858 Standard for Household Electric Ranges. Thus, there
exists a need to
effectively and automatically control the temperature of the food and/or
liquid being heated by a
stovetop electric heating element to ensure that the food and/or liquid are
not heated above a
desired temperature limit. There also exists a need to retrofit and/or update
existing electric
stoves, ranges, and cooktops with electric heating elements that conform to
the UL 858
standard. There additionally exists a need to be able to retrofit and/or
update existing electric
stoves, ranges, and cooktops with improved electric heating elements that do
not require any
adaptors to enable mounting thereto.
SUMMARY
[0002]
Disclosed are various embodiments of an electric heating element configured to
regulate heat applied to food and liquid being heated or cooked thereon. Also
disclosed are
various embodiments of an electric heating element configured for mounting to
a stove, range,
or cooktop and the like either with or without an adaptor.
[0003] In
one embodiment, an electric heating element of the instant disclosure includes
an
electrically resistive inner heating element, an electrically resistive outer
heating element, one or
more temperature sensors positioned along a cold leg of the inner heating
element, and a
controller. The controller is configured to respond to sensor data from the
one or more
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temperature sensors and selectively control the amount of electrical current
provided to the
inner heating element while maximum electrical current is provided to the
outer heating element.
[0004] In
another embodiment, an electric heating element includes: (1) an inner coiled
surface heating element including first and second cold legs, each of the
first and second cold
legs comprising first and second electrical conductors extending therefrom,
respectively, for
connection to an electrical power source, and (2) an outer coiled surface
heating element
including third and fourth cold legs, each of the third and fourth cold legs
comprising third and
fourth electrical conductors extending therefrom, respectively, for connection
to the electrical
power source. The third and fourth cold legs extend parallel to the first and
second cold legs
from the respective inner and outer coiled surface heating elements and the
third and fourth
cold legs are positioned adjacent to and above the respective first and second
cold legs. The
first and second electrical conductors are connected to the third and fourth
electrical conductors,
respectively. The electric heating element in this embodiment also includes:
(3) at least one
temperature sensor positioned in proximity to the inner coiled surface heating
element and
along one of the first, second, third, and fourth cold legs, and (4) a
controller comprising a
processor and memory, the controller coupled to the temperature sensor and
configured to
selectively turn on and turn off the inner coiled surface heating element
while maintaining the
operation of the outer coiled surface heating element.
[0005] In
another embodiment, an electric heating element includes: an electrically
resistive
inner heating element, an electrically resistive outer heating element
positioned around the inner
heating element, and one or more temperature sensors positioned along a cold
leg of the inner
heating element. The one or more temperature sensors include an electro-
mechanical
temperature controlling device. During operation, the electrically resistive
inner and outer
heating elements are energized with electricity to generate heat.
Upon sensing a
predetermined temperature from the generated heat, the electro-mechanical
temperature
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controlling device opens an electrical circuit to cause the electrically
resistive inner heating
element to de-energize and cycle off while electricity continues to be
delivered to the electrically
resistive outer heating element. After a predetermined time has elapsed, or
upon sensing a
desired change in temperature or a desired lower temperature has been reached
due to a
reduction in heat generated from the electric heating element, the electro-
mechanical
temperature controlling device closes the electrical circuit to allow the
electrically resistive inner
heating element to be cycled on again. The electro-mechanical temperature
controlling device
is configured to selectively turn on and turn off the electrically resistive
inner heating element
while maintaining the operation of the electrically resistive outer heating
element.
[0006] In
another embodiment, an electric heating element includes: (1) an inner coiled
heating element including first and second cold legs, each of the first and
second cold legs
comprising first and second electrical conductors extending therefrom,
respectively, for
connection to an electrical power source, and (2) an outer coiled heating
element including third
and fourth cold legs, each of the third and fourth cold legs comprising third
and fourth electrical
conductors extending therefrom, respectively, for connection to the electrical
power source. The
third and fourth cold legs extend parallel to the first and second cold legs
from the respective
inner and outer coiled heating elements and the third and fourth cold legs are
positioned
adjacent to and above the respective first and second cold legs. The first and
second electrical
conductors are connected to the third and fourth electrical conductors,
respectively. The electric
heating element in this embodiment also includes a bimetal thermostat
configured to selectively
allow and interrupt the flow of electricity to the inner coiled heating
element while maintaining
the operation of the outer coiled heating element. The bimetal thermostat is
configured to
interrupt the flow of electricity to the inner coiled heating element when the
temperature sensed
by the bimetal thermostat from heat generated by the electric heating element
is at or above a
predetermined high temperature, and is configured to restore the flow of
electricity to the inner
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coiled heating element when the temperature sensed by the bimetal thermostat
from heat
generated by the electric heating element is at or below a predetermined low
temperature.
[0007] In
another embodiment, an electric heating element includes: (1) an electrically
resistive inner heating element including an inner coiled heating portion and
first and second
cold legs extending from the inner coiled heating portion for connection to an
electrical power
source; (2) an electrically resistive outer heating element including an outer
coiled heating
portion positioned in a first common plane with and around the inner coiled
heating portion, the
outer heating element including third and fourth cold legs extending from the
outer coiled
heating portion for connection to the electrical power source, the third and
fourth cold legs
positioned parallel to and in a second common plane with the first and second
cold legs; and (3)
a controller positioned under the first common plane in proximity to the inner
coiled heating
portion and along one of the first and second cold legs, the controller
configured to selectively
open and close an electrical circuit to cycle off and on the inner coiled
heating portion
[0008] The
controller may be coupled to a timer to enable the controller to open the
electrical circuit after a predetermined amount of time has elapsed to turn
off the inner coiled
heating element while the outer coiled heating element remains energized. The
electric heating
element may include at least one temperature sensor coupled to the controller
to detect a
temperature associated with heat emitted from the inner heating element and/or
the outer
heating element. The controller may include a processor coupled to memory
having software
thereon that when executed causes the processor to selectively open and close
the electrical
circuit while the outer coiled heating element is energized. The controller
may be configured to
dynamically modulate electrical current delivered to the inner coiled heating
element.
[0009] The
controller may be a thermostat configured to selectively open and close the
electrical circuit to cycle off and on the inner coiled heating portion while
the outer coiled heating
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element remains energized. The thermostat includes a bimetal material
configured to: (a) open
the electrical circuit upon detecting a predetermined high temperature
associated with heat
emitted from the inner heating element and/or the outer heating element, and
(b) close the
electrical circuit upon detecting a predetermined low temperature associated
with heat emitted
from the outer heating element.
[0010] The
electric heating element may include an enclosure for housing the thermostat.
The enclosure may comprise a stainless steel. The enclosure may include a
first clamshell
portion, a second clamshell portion. A seal may be positioned between the
first and second
clamshells. The enclosure may be black on at least one surface.
[0011] The
electric heating element may include an enclosure for housing the controller
and
the at least one temperature sensor. The first common plane is parallel to the
second common
plane.
[00121 In
another embodiment, an electric heating element includes: (1) an electrically
resistive inner heating element including an inner coiled heating portion and
first and second
cold legs extending from the inner coiled heating portion for connection to an
electrical power
source; (2) an electrically resistive outer heating element including an outer
coiled heating
portion positioned in a common plane with and around the inner coiled heating
portion, the outer
heating element including third and fourth cold legs extending from the outer
coiled heating
portion for connection to the electrical power source, the third and fourth
cold legs positioned
parallel to the first and second cold legs, and (3) an electro-mechanical
controlling device
positioned under the common plane in proximity to the inner coiled heating
portion and along
one of the first and second cold legs, the electro-mechanical controlling
device configured to
selectively open and close an electrical circuit to cycle off and on the inner
coiled heating
portion.
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[0013] The
electro-mechanical controlling device may include a thermostat. The thermostat
may include a bimetal material configured to: (a) open the electrical circuit
upon detecting a
predetermined high temperature associated with heat emitted from the inner
heating element
and/or the outer heating element, and (b) close the electrical circuit upon
detecting a
predetermined low temperature associated with heat emitted from the outer
heating element.
[0014] The
electric heating element may include an enclosure for housing the electro-
mechanical controlling device. The third cold leg may be positioned adjacent
to and directly
above the first cold leg, the fourth cold leg may be positioned adjacent to
and directly above the
second cold leg, and the third cold leg may be positioned adjacent to and side
by side the fourth
cold leg. The electric heating element may include a bracket for supporting
the first, second,
third and fourth cold legs relative to one another, the bracket having an
interference fit with the
first, second, third, and fourth cold legs. The first, second, third and
fourth cold legs may be
parallel to the common plane and extend radially past an outermost diameter of
the outer coiled
heating portion. The electric heating element may include first, second,
third, and fourth
electrical conductors extending from the first, second, third and fourth cold
legs, respectively.
The first electrical conductor may be connected or jumpered to the third
electrical conductor and
the second electrical conductor may be connected or jumpered to the fourth
electrical
conductor, where the third and fourth electrical conductors may be configured
for engaging with
an appliance electrical receptacle having a single pair of electrical
conductor receiving ports.
[0015] In
another embodiment, an electric heating element includes: (1) an electrically
resistive inner heating element including an inner coiled heating portion and
first and second
cold legs extending from the inner coiled heating portion for connection to an
electrical power
source; (2) an electrically resistive outer heating element including an outer
coiled heating
portion positioned in a common plane with and around the inner coiled heating
portion, the outer
heating element including third and fourth cold legs extending from the outer
coiled heating
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portion for connection to the electrical power source, wherein the first,
second, third and fourth
cold legs are parallel to the common plane and extend radially past an
outermost diameter of
the outer coiled heating portion; (3) first, second, third, and fourth
electrical conductors
extending from the first, second, third and fourth cold legs, respectively,
wherein the first
electrical conductor is connected to the third electrical conductor and the
second electrical
conductor is connected to the fourth electrical conductor, wherein the third
and fourth electrical
conductors are configured for engaging with an appliance electrical receptacle
having a single
pair of electrical conductor receiving ports; (4) a thermostat housed in an
enclosure under the
common plane in proximity to the inner coiled heating portion and along one of
the first and
second cold legs, the thermostat configured to selectively open and close an
electrical circuit to
cycle off and on the inner coiled heating portion; and (5) a bracket oriented
perpendicularly to
the first, second, third, and fourth cold legs and positioned near a terminal
end of the first,
second, third, and fourth cold legs, the bracket configured to restrain the
first, second, third, and
fourth cold legs and to separate the first, second, third, and fourth cold
legs from one another.
[0016] In
another embodiment, an electric heating element includes: (1) an electrically
resistive inner heating element including an inner coiled heating portion and
first and second
cold legs extending from the inner coiled heating portion for connection to an
electrical power
source; (2) an electrically resistive outer heating element including an outer
coiled heating
portion positioned in a common plane with and around the inner coiled heating
portion, the outer
heating element including third and fourth cold legs extending from the outer
coiled heating
portion for connection to the electrical power source, the third and fourth
cold legs positioned
parallel to the first and second cold legs; and (3) a controller positioned
under the common
plane in proximity to the inner coiled heating portion and along one of the
first and second cold
legs, the controller configured to selectively open and close an electrical
circuit to cycle off and
on the inner coiled heating portion.
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[0017] The
controller may be coupled to a timer to enable the controller to open the
electrical circuit after a predetermined amount of time has elapsed to turn
off the inner coiled
heating element while the outer coiled heating element remains energized. The
electric heating
element may include at least one temperature sensor coupled to the controller
to detect a
temperature associated with heat emitted from the inner heating element and/or
the outer
heating element. The electric heating element may include an enclosure for
housing the at least
one temperature sensor. The controller may include a processor coupled to
memory having
software thereon that when executed causes the processor to selectively open
and close the
electrical circuit while the outer coiled heating element is energized. The
controller may be
configured to dynamically modulate electrical current delivered to the inner
coiled heating
element.
[0018] The
controller may be a thermostat configured to selectively open and close the
electrical circuit to cycle off and on the inner coiled heating portion while
the outer coiled heating
element remains energized. The thermostat may be configured to: (a) open the
electrical circuit
upon detecting a predetermined high temperature associated with heat emitted
from the inner
heating element and/or the outer heating element, and (b) close the electrical
circuit upon
detecting a predetermined low temperature associated with heat emitted from
the outer heating
element. The electric heating element may include an enclosure for housing the
thermostat.
The enclosure may comprise a stainless steel. The enclosure may include a top
portion and a
bottom portion. The top portion may include opposed end walls extending
downwardly from a
top wall, and the bottom portion may include opposed, slotted end walls and
opposed side walls
extending upwardly from a bottom wall. Each of the opposed, slotted end walls
of the bottom
portion may be configured to lie adjacent to respective opposed end walls of
the top portion.
The opposed end walls of the top portion may each include a circular aperture
to receive the
second cold leg of the inner coiled heating portion.
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[0019] In
another embodiment, an electric heating element includes: (1) an electrically
resistive inner heating element including an inner coiled heating portion and
first and second
cold legs extending from the inner coiled heating portion for connection to an
electrical power
source; (2) an electrically resistive outer heating element including an outer
coiled heating
portion positioned in a common plane with and around the inner coiled heating
portion, the outer
heating element including third and fourth cold legs extending from the outer
coiled heating
portion for connection to the electrical power source, the third and fourth
cold legs positioned
parallel to the first and second cold legs; and (3) a thermostat positioned
under the common
plane in proximity to the inner coiled heating portion and along one of the
first and second cold
legs, the thermostat is configured to selectively open and close an electrical
circuit to cycle off
and on the inner coiled heating portion.
[0020] The
thermostat may include a bimetal material configured to: (a) open the
electrical
circuit upon detecting a predetermined high temperature associated with heat
emitted from the
inner heating element and/or the outer heating element, and (b) close the
electrical circuit upon
detecting a predetermined low temperature associated with heat emitted from
the outer heating
element. The electric heating element may include an enclosure for housing the
thermostat.
[0021] The
third cold leg may be positioned adjacent to and directly above the first cold
leg
and the second cold leg may be positioned between the third and fourth cold
legs. The second
cold leg may lie along a central plane of the electric heating element that is
normal to the
common plane. The electric heating element may include an enclosure for
housing the
thermostat and the thermostat may be positioned along the second cold leg. The
first, second,
third and fourth cold legs may be parallel to the common plane and extend
radially past an
outermost diameter of the outer coiled heating portion. The electric heating
element may
include first, second, third, and fourth electrical conductors extending from
the first, second, third
and fourth cold legs, respectively. The first electrical conductor may be
connected to the third
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electrical conductor and the second electrical conductor may be connected to
the fourth
electrical conductor. The third and fourth electrical conductors may be
configured for engaging
with an appliance electrical receptacle having a single pair of electrical
conductor receiving
ports.
[0022] In
another embodiment, an electric heating element includes: (1) an electrically
resistive inner heating element including an inner coiled heating portion and
first and second
cold legs extending from the inner coiled heating portion for connection to an
electrical power
source; (2) an electrically resistive outer heating element including an outer
coiled heating
portion positioned in a common plane with and around the inner coiled heating
portion, the outer
heating element including third and fourth cold legs extending from the outer
coiled heating
portion for connection to the electrical power source, wherein the first,
second, third and fourth
cold legs are parallel to the common plane and extend radially past an
outermost diameter of
the outer coiled heating portion, wherein the third cold leg is positioned
adjacent to and directly
above the first cold leg and the second cold leg is positioned between the
third and fourth cold
legs, wherein the second cold leg lies along a central plane of the electric
heating element that
is normal to the common plane; (3) first, second, third, and fourth electrical
conductors
extending from the first, second, third and fourth cold legs, respectively,
wherein the first
electrical conductor is connected to the third electrical conductor and the
second electrical
conductor is connected to the fourth electrical conductor, wherein the third
and fourth electrical
conductors are configured for engaging with an appliance electrical receptacle
having a single
pair of electrical conductor receiving ports; (4) a thermostat housed in an
enclosure under the
common plane in proximity to the inner coiled heating portion and along one of
the first and
second cold legs, the thermostat configured to selectively open and close an
electrical circuit to
cycle off and on the inner coiled heating portion; and (5) a bracket oriented
perpendicularly to
the first, second, third, and fourth cold legs and positioned near a terminal
end of the first,
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second, third, and fourth cold legs to restrain the first, second, third, and
fourth cold legs near
the terminal end.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Fig. 1 is a perspective view of an embodiment of an electric heating
element of the
instant disclosure.
[0024] Fig. 2 is a top plan of view of the heating element of Fig. 1.
[0025] Fig. 3 is a front view of the heating element of Fig. 2.
[0026] Fig. 4 is a right side view of the heating element of Fig. 2.
[0027] Fig. 5 is a schematic view of a system for operating at least one
aspect of an electric
heating element of the instant disclosure.
[0028] Fig. 6 is a perspective view of another embodiment of an electric
heating element of
the instant disclosure.
[0029] Fig. 7 is a top plan view of the heating element of Fig. 6.
[0030] Fig. 8 is a front view of the heating element of Fig. 7.
[0031] Fig. 9 is a section view of the heating element of Fig. 7 drawn at
station A-A.
[0032] Fig. 10 is a perspective view of an embodiment of another heating
element of the
instant disclosure.
[0033] Fig. 11 is a top view of the heating element of Fig. 10.
[0034] Fig. 12 is a front view of the heating element of Fig. 10.
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[0035] Fig. 13 a right side view of the heating element of Fig. 10.
[0036] Fig. 14 is a partial perspective view of a portion of the heating
element of Fig. 10.
[0037] Fig. 15 is a perspective view of an embodiment of another heating
element of the
instant disclosure.
[0038] Fig. 16 is a top view of the heating element of Fig. 15.
[0039] Fig. 17 is a front view of the heating element of Fig. 15.
[0040] Fig. 18 a right side view of the heating element of Fig. 15.
[0041] Fig. 19 a left side view of the heating element of Fig. 15.
[0042] Fig. 20 is a partial perspective view of a portion of the heating
element of Fig. 15.
[0043] Fig. 211s a perspective view of an embodiment of another heating
element of the
instant disclosure.
[0044] Fig. 22 is a bottom plan view of the heating element of Fig. 21.
[0045] Fig. 23 is a front view of the heating element of Fig. 21.
[0046] Fig. 24 is a right side view of the heating element of Fig. 21.
[0047] Fig. 25 is a rear view of the heating element of Fig. 21.
[0048] Fig. 26 is a top plan view of the heating element of Fig. 21.
[0049] Fig. 27 is a left side view of the heating element of Fig. 21.
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[0050] Fig. 28 is cross sectional view of the heating element of Fig. 26
taken along the
longitudinal axis of cold leg 271.
[0051] Fig. 29 is a partial exploded perspective view of the heating
element of Fig. 21.
[0052] Fig. 30 is a right side partial exploded view of the heating element
of Fig. 29.
[0053] Fig. 31 is a bottom perspective view of the heating element of Fig.
29 shown without
a portion of an enclosure.
[0054] Fig. 32 is a partial detail perspective view of the heating element
of Fig. 21.
[0055] Fig. 33 is a partial detail bottom perspective view of the heating
element of Fig. 21.
DETAILED DESCRIPTION
[0056] Although the figures and the instant disclosure describe one or more
embodiments of
a heating element, one of ordinary skill in the art would appreciate that the
teachings of the
instant disclosure would not be limited to these embodiments. For example, the
teachings of
the instant disclosure may be applied to controlling the temperature or heat
output of any
heating element. It should be appreciated that any of the features of an
embodiment discussed
with reference to the figures herein may be combined with or substituted for
features discussed
in connection with other embodiments in this disclosure.
[0057] Turning now to the figures, wherein like reference numerals refer to
like elements,
there is shown one or more embodiments of an electric heating element. Figs. 1-
4 illustrate an
embodiment of a dual coil electric heating element 100. In this embodiment,
heating element
100 includes electrically resistive inner heating element 110, electrically
resistive outer heating
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element 112, one or more temperature sensors 115, spider bracket 117, and
terminal bracket
118.
[0058]
Inner heating element 110 includes cold leg 119, cold leg 121, and coiled
portion
123. Outer heating element 112 includes cold leg 120, cold leg 122, and coiled
portion 124.
The respective cold legs 119,120,121,122 are configured to not generate heat
when the
respective heating elements 110,112 are electrically energized. The respective
coiled portions
123,124 are configured to generate heat when the respective heating elements
110,112 are
electrically energized. The respective coiled portions 123,124 of the
respective heating
elements 110,112 lie in the same plane and in a generally concentric,
counterclockwise spiral
around a common center. More specifically, the coiled portion 124 of outer
heating element 112
lies in a generally concentric, counterclockwise spiral around the coiled
portion 123 of the inner
heating element 110, and coiled portion 123 of the inner heating element 110
lies in a generally
concentric, counterclockwise spiral around a center location that is common to
both the outer
heating element 112 and the inner heating element 110. In other embodiments,
the coiled
portions 123,124 may lie in a generally clockwise arrangement.
[0059] To
connect heating element 100 to an electrical power source, inner heating
element
110 includes electrical terminals 131,133 extending from the end portions of
cold legs 121,119,
respectively, and outer heating element 112 includes electrical terminals
134,136 extending
from the end portions of cold legs 122,120, respectively. As shown in Figs. 1-
3, the terminal/end
portion of cold legs 119,120,121,122 are positioned side by side in
approximately the same
plane. The side-by-side terminals 131,133,134,136 may be connected to a four-
terminal
receptacle to connect heating element 100 to an electrical power source. In
other
embodiments, terminals 131,133,134,136 may be connected to a four-terminal to
two-terminal
adaptor for connection with conventional two-terminal receptacle stoves,
ranges, and cooktops.
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[0060]
Terminal bracket 118 supports at least adjacent cold legs 119,120 and is
configured
to stabilize the separate inner and outer heating elements 110,112 relative to
one another.
Terminal bracket 118 may be used to electrically ground electric heating
element 100. Terminal
bracket 118 may be positioned somewhat near the terminal end of cold legs
119,120 along the
sheathed portion of cold legs 119,120. Terminal bracket 118 may include one or
more
apertures, cutouts, grooves, straps, or other similar features to maintain
position of cold legs
119,120. Terminal bracket 118 may be configured to have a close fit or an
interference fit with
the outer perimeter of cold legs cold legs 119,120. In other embodiments,
terminal bracket 118
supports cold legs 119,120,121,122.
[0061] In
the embodiment shown in the figures, terminal bracket 118 includes a pair of
apertures. The sheathed end of the cold legs 119,120 may be slightly tapered
to allow the
terminal bracket 118 during assembly to slide onto and wedge against the cold
legs 119,120.
The apertures in the bracket 118 may be sized to snuggly fit the diameter
along any portion of
cold legs 119,120 near the terminal end. In other embodiments, the geometry
and/or manner of
securing bracket 118 to cold legs 119,120 may be different without departing
from the scope of
the instant disclosure.
[0062]
Terminal bracket 118 may be configured from an electrically conductive
material,
such as a metal. Terminal bracket 118 may be configured from a thermally
resistant material.
Terminal bracket 118 may be used to electrically ground electric heating
element 100. Terminal
bracket 118 may be formed from a stamping, a forging, a casting, a machined
article, a 3-D
printed article, or any other suitable manufacturing method.
[0063]
Spider bracket 117 is configured to support coiled portions 123,124 of the
inner and
outer heating elements 110,112, respectively, relative to one another. Spider
bracket 117 may
be configured with three legs arranged at approximately equal angles with
respect to one
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another from a central location, as shown in the figures, or in any other
quantity of legs, shape
or configuration to support the inner and outer heating elements 110,112.
Spider bracket 117
may include upwardly extending protrusions 146 on each leg so as to restrain
and/or help
maintain position of one or more portions of coiled portions 123,124 relative
to spider bracket
117. In other embodiments, spider bracket 117 may include recessed receptacles
formed in
each leg to accomplish this purpose.
[0064]
Heating elements 110,112 may include a tubular sheathed configuration. The
cross
sectional profile of heating elements 110,112 may include a generally
trapezoidal shape with a
flat top surface, downwardly sloped and opposed side walls, and a curved
bottom wall
positioned opposite the flat top surface and joined to the opposed side walls.
A relatively small
transitional radius may exist between the each of the side walls and the top
flat surface. In
other embodiments, the cross sectional profile of heating elements 110,112 may
have any
shape.
[0065] One
or more temperature sensors 115 may be connected to either or both of heating
elements 110,112 for sensing the temperature of a cooking utensil positioned
on the top flat
surface of heating elements 110,112. To minimize erroneous temperature
readings and
damage from excessive exposure to heat generated from heating elements
110,112, the one or
more temperature sensors 115 may be positioned along cold legs 119,120,121, or
122 (along
cold leg 121 of inner heating element 110 is shown). The one or more
temperature sensors 115
may include a thermocouple or a thermostat having a relatively small bimetal
material, which in
turn allows for quicker reset of the switch (discussed below) for improved
cooking performance.
As discussed more fully below, by positioning one or more temperature sensors
115 along cold
leg 121 of inner heating element 110, selective on/off control of the inner
coiled portion 123
while maintaining continuous heating of the outer heating element 112 improves
cooking
performance while minimizing overcooking.
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[0066] In
some embodiments, the one or more temperature sensors 115 comprises a
bimetal thermostat positioned along a cold leg, such as cold leg 121 (as
shown, for example, in
Fig. 4) or along a cold leg 120. The thermostat may selectively control
delivery of electrical
current to heating element 100. The bimetal material of the thermostat may be
configured to
open an electrical circuit upon reaching a desired, predetermined temperature
thereby shutting
off power to inner heating element 110. For example, when a thermostat is
positioned along
cold leg 121, electrical current to the inner coiled portion 123 is ceased
when the bimetal
material of the thermostat opens the circuit while electrical current to the
outer coiled portion
124 continues at its maximum or other desired setting.
[0067]
Depending on available space and size of the thermostat and/or thermostat
housing
and desired responsiveness, a thermostat may be positioned along a cold leg of
the outer
heating element 112, such as cold leg 120 to provide selective on/off control
of the outer coiled
portion 124 while maintaining continuous heating of the inner heating element
110. In
embodiments when a thermostat is positioned along cold leg 120, for example,
electrical current
to the outer coiled portion 124 is ceased when the bimetal material of the
thermostat opens the
circuit while electrical current to the inner coiled portion 123 continues at
its maximum or other
desired setting.
[0068]
Upon ceasing the flow of electrical current, the inner heating element 110 (or
the
outer heating element 112 as the case may be) and the bimetal material of the
thermostat will
tend to cool due to reduced heat being generated from the heating element 100.
When the
bimetal material of the thermostat is cooled to a desired, predetermined
temperature, the
thermostat may "reset" by closing the circuit to allow electricity to flow
again to the inner heating
element 110. How quickly the thermostat resets and the modulation of heat
radiating from
heating element 100 may be a function of various factors, including the
thermostat size, the
configuration and extent of thermostat shielding (e.g., from the housing
described below),
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protective barriers or coatings applied to internal or external surfaces to,
for example, thermal
shielding (e.g., coating or lining a thermostat housing with a reflective or a
nonreflective material
or a colored paint), and relative position of the thermostat along a cold leg
with respect to the
radiant heat from the inner heating element 110 and the outer heating element
112. In some
embodiments, a paint or coating may be applied to a surface of the thermostat
or to an
enclosure housing the thermostat for controlling a rate of exposure of the
thermostat to heat
from the inner heating element 110 and/or the outer heating element 112. The
paint or coating
may minimize the potential for overshoot of a desired temperature thereby
allowing enhanced
responsiveness by the thermostat and quicker reset. In some embodiments, the
paint or
coating may be black. In other embodiments, the paint or coating may be any
other color.
[0069] In
other embodiments, the one or more temperature sensors 115 may include or be
coupled to an electrical switch 142 (see Fig. 5) to turn on and/or turn off
electrical current to a
designated inner heating element 110 or an outer heating element 112 or both.
A controller 140
comprising a microprocessor and memory may be coupled to the one or more
temperature
sensors 115 and to the switch 142, and upon receiving a signal and/or sensor
data from the one
or more temperature sensors 115, may command the switch 142 to open and/or
close to turn on
and/or turn off electrical current to a designated inner heating element 110
or an outer heating
element 112 or both. The signal and/or sensor data may be a sensed temperature
or
interpreted as a sensed temperature by the controller 140. In some
embodiments, the controller
140 may command the switch 142 to open and/or close to turn on and/or turn off
electrical
current to a designated inner heating element 110 or an outer heating element
112 or both
irrespective of any sensor data received from the one or more temperature
sensors 115. The
controller 140 may be configured to interpret temperature gradients sensed or
measured over a
period of time. The controller 140 may be configured to open and/or close the
switch in
advance of actually reaching a predetermined temperature according to the
temperature
18
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gradient to ensure, for example, a predetermined maximum temperature of the
cooking utensil
and/or to ensure maintaining an optimum mean operating temperature of the
heating element
100 according to the item being heated or cooked thereon.
[0070] In
some embodiments, in response to sensor data received from the one or more
temperature sensors 115, the controller 140 may be configured to dynamically
modulate the
flow of electrical current to, and thus heat output from, a designated inner
heating element 110
or outer heating element 112 or both.
[0071] The
controller 140 may include preprogrammed logic to automatically control the
temperature of the cooking utensil and/or the item being heated or cooked
therein after the user
sets the heating element 100 to its maximum "on" position thereby energizing
both the inner and
the outer coiled portions 123,124. The controller 140 may be programmed to
selectively control
delivery of electrical current to heating element 100. For example, in some
embodiments,
electrical current to the inner coiled portion 123 is ceased while electrical
current to the outer
coiled portion 124 continues at its maximum setting. In other embodiments,
electrical current to
the outer coiled portion 124 is ceased while electrical current to the inner
coiled portion 123
continues at its maximum setting.
[0072] In
various embodiments, when a predetermined temperature of the cooking utensil
is
reached, as sensed by the one or more temperature sensors 115 and/or
interpreted by the
controller 140, the controller 140 may command the switch 142 to open to cease
the flow of
electrical current to one of the inner coiled portion 123 or the outer coiled
portion 124 for a
predetermined period of time, until a predetermined change in temperature is
sensed by the one
or more temperature sensors 115, or until a predetermined lower temperature is
sensed by the
one or more temperature sensors 115.
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[0073]
When either the predetermined period of time has elapsed, the predetermined
change in temperature is sensed, or the predetermined lower temperature is
sensed, the
controller 140 may command the switch 142 to close so to reinstate the flow of
electrical current
to the coiled portion 123 or 124 that was earlier ceased. The time at which
the controller 140,
via the switch 142, turns off the flow of electrical current and reinstates
the flow of electrical
current to an affected inner or outer coiled portion 123,124 may be affected
by how quickly the
change in temperature of the cooking utensil reaches the one or more
temperature sensors 115
that results from the change in electrical current. Factors that may influence
the timing for
opening and closing the switch include the proximity of the one or more
temperature sensors
115 to the cooking utensil and whether a thermal insulator or a thermal
conductor or both is
positioned between the one or more temperature sensors 115 and the cooking
utensil. The
timing may be calibrated to account for these and other factors to maximize
the performance of
the heating element 100.
[0074] The
controller 140 described herein may include and/or be connected to one or more
CPU's, memory, data buses, switches, sensors, displays, user interfaces, and
software
configured to respond to and/or carry out computer commands.
[0075]
Figs. 6-9 illustrate an embodiment of a dual coil electric heating element 100
shown
with a protective housing 130 for housing and protecting temperature sensor
115 from dust,
debris, food, liquids, and excessive or undesirable temperatures, and for
enabling optimum
performance of temperature sensor 115 in a smaller package. In some
embodiments, housing
130 may be configured to house one or more temperature sensors 115. Housing
130 protects
the temperature sensor 115 from exposure to liquids and excessive heat.
Housing 130 may
include a clamshell configuration with a clamshell seam generally lying in a
horizontal plane. In
this configuration, housing 130 may include upper shell portion 135 and lower
shell portion 137
that may be laser welded and/or crimped together to house one or more
temperature sensors
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115 to provide a design simplicity and smaller/lower profile of the upper
shell portion 135, and
fewer points of entry for liquids as may occur during immersion of heating
element 100 in soap
and water during cleaning. In other embodiments, the clamshell configuration
of housing 130
may be oriented side-to-side such that the clamshell seam generally lies in
vertical plane and
the clamshell includes a right shell portion and a left shell portion instead
of upper shell portion
135 and lower shell portion 137.
[0076] In
the embodiment shown in the figures, at least upper shell portion 135 may be
made from a thermally conductive material, such as a stainless steel, which
enables excellent
coupling and robust adhesion of the cap/cup of the temperature sensor 115 to
the upper shell
portion 135. Lower shell portion 137 may also be made from a thermally
conductive material,
such as a stainless steel, to provide an improved heat sink for the upper
shell portion 135 and a
faster switch reset, thus enabling improved cooking performance or use of a
clad metal to
achieve the same function. In addition, use of a thermally conductive material
for housing 130
helps to ensure heat transfer to and from the temperature sensor 115,
resulting in faster
response to both heating and cooling cycles.
[0077] To
control or enhance the amount or rate of heat transfer or otherwise enhance
the
performance of temperature sensor 115, housing 130 may also include one or
more coatings,
as described above. For example, housing 130 may include a coating applied to
internal or
external surfaces to, for example, upper shell portion 135, lower shell
portion 137, or both. The
coating may be applied to one or more surfaces of housing 130 in a manner or
orientation that
helps ensure quick reset by the one or more temperature sensors 115. As
described above, the
coating may be in the form of paint, such as paint in the color black or any
other suitable color,
which may be configured to induce heat transfer of heat radiated from electric
heating element
100. In other embodiments, the coating may be applied to a surface of the one
or more
temperature sensors 115 to control or enhance the amount or rate of exposure
of the one or
21 .
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more temperature sensors 115 to heat from the inner heating element 110 and/or
the outer
heating element 112. In this way, the potential for overshoot of a desired
temperature may be
minimized, thereby allowing enhanced responsiveness by the thermostat and
quicker reset.
[0078]
Housing 130 may include one or more ribs to provide increased housing rigidity
while
allowing for reduced thermal mass by allowing thinner wall thickness of the
housing 130. For
example, either or both of upper shell portion 135 and lower shell portion 137
may include ribs
positioned on an inner surface of upper shell portion 135 and/or lower shell
portion 137 to
provide rigidity to the respective upper and lower shell portions while
minimizing the wall
thickness of the respective shell portions to maximize heat transfer through
the respective shell
portions.
[0079]
Laser welded housing 130 coupled with resistance (spot) welding of a cold pin
to the
temperature sensor 115 enables the use of a very short weld tab/cold pin
configuration and a
proportional reduction in the size of the housing 130. The relatively small
size of housing 130
enables placement of the one or more temperature sensors 115 in close
proximity to the heated
coil portions 123,124 of the heating element 100 and above the drip pan that
normally lies below
the heating element on a stovetop or similar apparatus, thereby providing easy
interchangeability with conventionally designed heating elements that lack the
one or more
temperature sensors 115. In some embodiments, the one or more temperature
sensors 115
may be a bimetal thermostat operable as described above.
[0080] In
some embodiments, controller 140, switch 142, and the one or more temperature
sensors 115 may be housed in housing 130. In other embodiments, the controller
140 and/or
switch 142 are positioned upstream of electrical terminals 131,133,134,136.
The one or more
temperature sensors 115 may be configured to perform the tasks of sensing
temperature and
also acting as the switch 142.
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[0081]
Figs. 10-14 illustrate an embodiment of a dual coil electric heating element
150
having a compact terminal portion 155 that enables easy interchangeability for
conventional
heating elements having a conventional, two-terminal design. To enable adaptor-
free
installation into conventional twin-terminal receptacles, which would be
required if the electric
heating element is configured with four terminals like that shown in Figs. 1-
9, compact terminal
portion 155 of electric heating element 150 conveniently bundles respective
inner and outer
positive and negative terminals together to form a single pair of terminals
for insertion into a
conventional two-terminal heating element receptacle. This embodiment may have
some or all
of the same features as described above to obtain precise temperature control
of the cooking
utensil and/or the item being heated or cooked therein. For example, in this
embodiment,
heating element 150 includes electrically resistive inner heating element 160,
electrically
resistive outer heating element 162, one or more temperature sensors 165,
spider bracket 167,
and terminal bracket 168 in addition to compact terminal portion 155.
[0082]
Inner heating element 160 includes cold leg 169, cold leg 171, and coifed
portion
173. Outer heating element 162 includes cold leg 170, cold leg 172, and coiled
portion 174.
The respective cold legs 169,170,171,172 are configured to not generate heat
when the
respective heating elements 160,162 are electrically energized. The respective
coiled portions
173,174 are configured to generate heat when the respective heating elements
160,162 are
electrically energized. The respective coiled portions 173,174 of the
respective heating
elements 160,162 lie in the same plane and in a generally concentric,
counterclockwise spiral
around a common center. More specifically, the coiled portion 174 of outer
heating element 162
lies in a generally concentric, counterclockwise spiral around the coiled
portion 173 of the inner
heating element 160, and coiled portion 173 of the inner heating element 160
lies in a generally
concentric, counterclockwise spiral around a center location that is common to
both the outer
23
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heating element 162 and the inner heating element 160. In other embodiments,
the coiled
portions 173,174 may lie in a generally clockwise arrangement.
[0083] As
shown in the figures, the end portions of cold legs 169,170,171,172 are
arranged
on top of one another and adjacent one another in a nested and compact
arrangement from
which a pair of terminals 184,186 extend for connecting to an electrical power
source. More
specifically, the end portion of cold leg 169 of inner heating element 160 is
positioned beneath
the end portion of cold leg 172 of outer heating element 162, and the end
portion of cold leg 171
of inner heating element 160 is positioned beneath the end portion of cold leg
170 of outer
heating element 162. The end portion of cold leg 169 is positioned adjacent to
and side by side
with the end portion of cold leg 171, and the end portion of cold leg 172 is
positioned adjacent to
and side by side with the end portion of cold leg 170.
[0084] To
connect heating element 150 to an electrical power source, inner heating
element
160 includes electrical terminals 181,183 extending from the end portions of
cold legs 171,169,
respectively, and outer heating element 162 includes electrical terminals
184,186 extending
from the end portions of cold legs 172,170, respectively. As best shown in
Fig. 14, terminal 181
is connected to terminal 186 and terminal 183 is connected to terminal 184.
In this
embodiment, the electrical conductor 179 of terminal 181 is bent upwardly and
soldered or
brazed to, or otherwise joined with, the electrical conductor 178 of terminal
186 at a location
some distance away from the end of terminal 186. Similarly, the electrical
conductor 177 of
terminal 183 is bent upwardly and soldered or brazed to, or otherwise joined
with, the electrical
conductor 176 of terminal 184 at a location some distance away from the end of
terminal 184.
In other embodiments, terminals 181 and 183 may be jumpered to terminals 186
and 184,
respectively. Positioning and connecting the conductors 177 and 179 to
conductors 176 and
178, respectively, allows for direct connection of terminals 184 and 186 to an
electrical power
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source on a conventional two-terminal receptacle stovetop, cooktop, or range
appliance without
requiring a 4 terminal-to-2-terminal receptacle adaptor.
[0085]
Terminal bracket 168 supports respective cold legs 169,170,171,172 and is
configured to stabilize the inner and outer heating elements 160,162 relative
to one another.
Terminal bracket 168 may be used to electrically ground electric heating
element 150. Spider
bracket 167 is configured to support coiled portions 173,174 of the inner and
outer heating
elements 160,162, respectively, relative to one another. Spider bracket 167
may be configured
with three legs arranged at approximately equal angles with respect to one
another from a
central location, as shown in the figures, or in any other quantity of legs,
shape or configuration
to support the inner and outer heating elements 160,162. Spider bracket 167
may include
upwardly extending protrusions 196 on each leg so as to restrain and/or help
maintain position
of one or more portions of coiled portions 173,174 relative to spider bracket
167. In other
embodiments, spider bracket 167 may include recessed receptacles formed in
each leg to
accomplish this purpose.
[0086]
Heating elements 160,162 may include a tubular sheathed configuration. The
cross
sectional profile of heating elements 160,162 may include a generally
trapezoidal shape with a
flat top surface, downwardly sloped and opposed side walls, and a curved
bottom wall
positioned opposite the flat top surface and joined to the opposed side walls.
A relatively small
transitional radius may exist between the each of the side walls and the top
flat surface. In
other embodiments, the cross sectional profile of heating elements 160,162 may
have any
shape.
[0087] One
or more temperature sensors 165 may be connected to either or both of heating
elements 160,162 for sensing the temperature of a cooking utensil positioned
on the top flat
surface of heating elements 160,162. To minimize erroneous temperature
readings and
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damage from excessive exposure to heat generated from heating elements
160,162, the one or
more temperature sensors 165 may be positioned along cold legs 169,170,171,172
(along cold
leg 171 of inner heating element 160 is shown). The one or more temperature
sensors 165 may
include a thermocouple or a relatively small thermostat having a relatively
small bimetal
material, which in turn allows for quicker reset of the switch (discussed
below) for improved
cooking performance. By positioning one or more temperature sensors 165 along
cold leg 171
of inner heating element 160, selective on/off control of the inner coiled
portion 173 while
maintaining continuous heating of the outer heating element 162 improves
cooking performance
while minimizing overcooking.
[0088] In
some embodiments, the one or more temperature sensors 165 comprises a
bimetal thermostat positioned along a cold leg, such as cold leg 171 (as
shown, for example, in
Fig. 13). The thermostat may selectively control delivery of electrical
current to heating element
150. The bimetal material of the thermostat may be configured to open an
electrical circuit upon
reaching a desired, predetermined temperature thereby shutting off power to
inner heating
element 160. For example, when a thermostat is positioned along cold leg 171,
electrical
current to the inner coiled portion 173 is ceased when the bimetal material of
the thermostat
opens the circuit while electrical current to the outer coiled portion 174
continues at its maximum
or other desired setting.
[0089]
Depending on available space and size of the thermostat and/or thermostat
housing,
a thermostat may be positioned along a cold leg of the outer heating element
162, such as cold
leg 170 to provide selective on/off control of the outer coiled portion 174
while maintaining
continuous heating of the inner heating element 160. In embodiments when a
thermostat is
positioned along cold leg 170, for example, electrical current to the outer
coiled portion 174 is
ceased when the bimetal material of the thermostat opens the circuit while
electrical current to
the inner coiled portion 173 continues at its maximum or other desired
setting.
26
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[0090]
Upon ceasing the flow of electrical current, the inner heating element 160 (or
the
outer heating element 162 as the case may be) and the bimetal material of the
thermostat will
tend to cool due to reduced heat being generated from the heating element 150.
When the
bimetal material of the thermostat is cooled to a desired, predetermined
temperature, the
thermostat may "reset" by closing the circuit to allow electricity to flow
again to the inner heating
element 160. How quickly the thermostat resets and the modulation of heat
radiating from
heating element 150 may be a function of various factors, including the
thermostat size, the
configuration and extent of thermostat shielding (e.g., from the housing
described below),
protective barriers or coatings applied to internal or external surfaces to,
for example, thermal
shielding (e.g., coating or lining a thermostat housing with a reflective or a
nonreflective material
or a colored paint), and relative position of the thermostat along a cold leg
with respect to the
radiant heat from the inner heating element 160 and the outer heating element
162. As
described above, some embodiments may include a paint or a coating applied to
a surface of
the thermostat or to a surface of the enclosure that houses the thermostat,
such as housing
180, to control the amount or the rate of exposure of the thermostat to heat
from the inner
heating element 160 and/or the outer heating element 162.
[0091] In
other embodiments, the one or more temperature sensors 165 may include or be
coupled to an electrical switch, such as switch 142 described above to turn on
and/or turn off
electrical current to a designated inner heating element 160 or outer heating
element 162 or
both. A controller 140 comprising a microprocessor and memory may be coupled
to the one or
more temperature sensors 165 and to the switch 142, and upon receiving a
signal and/or sensor
data from the one or more temperature sensors 165, may command the switch 142
to open
and/or close to turn on and/or turn off electrical current to a designated
inner heating element
160 or outer heating element 162 or both. The signal and/or sensor data may be
a sensed
temperature or interpreted as a sensed temperature by the controller 140. The
features and
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functionality of controller 140 with respect to the operation of electric
heating element 150 may
be the same as described above for electric heating element 100.
[0092]
Electric heating element 150 may include a protective housing 180 for housing
and
protecting the one or more temperature sensors 165 from dust, debris, food,
liquids, and
excessive or undesirable temperatures, and for enabling optimum performance of
the one or
more temperature sensors 165 in a smaller package. In some embodiments,
housing 180 may
be configured to house one or more temperature sensors 165. Housing 180 may
have all of the
same features as housing 130 described above.
[0093] In
one embodiment, as best shown in Figs. 10 and 12, the one or more temperature
sensors 165 and its protective housing 180 (or 130 as the case may be) are
positioned along
the cold leg 171 and underneath the inner coiled portion 173 and the outer
coiled portion 174. A
first end of cold leg 171 extends from the housing 180 and terminates at
terminal 186 via
terminal 181 and conductors 179,178. A second end of cold leg 171 extends from
housing 180
toward the center of the electric heating element 150 below one leg of spider
bracket 167. The
second end turns upwardly after exiting housing 180 and then turns
horizontally to transition to
inner coiled portion 173 of inner heating element 160. This arrangement
permits a relatively
small radius for the first counterclockwise turn of inner coiled portion 173
of inner heating
element 160, which minimizes the size of any unheated area in the center
portion of electric
heating element 150. As described above, the one or more temperature sensors,
whether or
not housed in an enclosure, such as housing 180, may be positioned above the
drip pan that
normally lies below the heating element on a stovetop or similar apparatus.
[0094]
Figs. 15-20 illustrate an embodiment of a dual coil electric heating element
200
without a temperature sensor but including electrically resistive inner
heating element 210,
electrically resistive outer heating element 212, spider bracket 217, terminal
bracket 218, and
28
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compact terminal portion 205. Each of these components may have the same
features or
attributes as described in any of the embodiments described herein. For
example, compact
terminal portion 205 may have the same features or attributes as compact
terminal portion 155.
This configuration enables easy interchangeability with conventional heating
elements having a
twin-terminal design while providing the advantage of increased wattage over a
conventional,
single coil electric heating element. To enable adaptor-free installation into
conventional twin-
terminal receptacles, which would be required if the electric heating element
is configured with
four terminals like that shown in Figs. 1-9, compact terminal portion 205 of
electric heating
element 200 conveniently bundles respective inner and outer positive and
negative terminals
together to form a single pair of terminals for insertion into a conventional
two-terminal heating
element receptacle.
[0095]
Inner heating element 210 includes cold leg 219, cold leg 221, and coiled
portion
223. Outer heating element 212 includes cold leg 220, cold leg 222, and coiled
portion 224.
The respective cold legs 219,220,221,222 are configured to not generate heat
when the
respective heating elements 210,212 are electrically energized. The respective
coiled portions
223,224 are configured to generate heat when the respective heating elements
210,212 are
electrically energized. The respective coiled portions 223,224 of the
respective heating
elements 210,212 lie in the same plane and in a generally concentric,
counterclockwise spiral
around a common center. More specifically, the coiled portion 224 of outer
heating element 212
lies in a generally concentric, counterclockwise spiral around the coiled
portion 223 of the inner
heating element 210, and coiled portion 223 of the inner heating element 210
lies in a generally
concentric, counterclockwise spiral around a center location that is common to
both the outer
heating element 212 and the inner heating element 210. In other embodiments,
the coiled
portions 223,224 may lie in a generally clockwise arrangement.
29
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[0096] As
shown in the figures, the end portions of cold legs 219,220,221,222 are
arranged
on top of one another and adjacent one another in a nested and compact
arrangement from
which a pair of terminals 234,236 extend for connecting to an electrical power
source. More
specifically, the end portion of cold leg 219 of inner heating element 210 is
positioned beneath
the end portion of cold leg 222 of outer heating element 212, and the end
portion of cold leg 221
of inner heating element 210 is positioned beneath the end portion of cold leg
220 of outer
heating element 212. The end portion of cold leg 219 is positioned adjacent to
and side by side
with the end portion of cold leg 221, and the end portion of cold leg 222 is
positioned adjacent to
and side by side with the end portion of cold leg 220. In other embodiments,
the end portion of
cold leg 219 is positioned adjacent to and side by side with the end portion
of cold leg 222, and
the end portion of cold leg 221 is positioned adjacent to and side by side
with the end portion of
cold leg 220.
[0097] To
connect heating element 200 to an electrical power source, inner heating
element
210 includes electrical terminals 231,233 extending from the end portions of
cold legs 221,219,
respectively, and outer heating element 212 includes electrical terminals
234,236 extending
from the end portions of cold legs 222,220, respectively. As best shown in
Fig. 20, terminal 231
is connected to terminal 236 and terminal 233 is connected to terminal 234. In
this
embodiment, the electrical conductor 229 of terminal 231 is bent upwardly and
soldered or
brazed to, or otherwise joined with, the electrical conductor 228 of terminal
236 at a location
some distance away from the end of terminal 236. Similarly, the electrical
conductor 227 of
terminal 233 is bent upwardly and soldered or brazed to, or otherwise joined
with, the electrical
conductor 226 of terminal 234 at a location some distance away from the end of
terminal 234.
In other embodiments, terminals 231 and 233 may be jumpered to terminals 236
and 234,
respectively. Positioning and connecting the conductors 227 and 229 to
conductors 226 and
228, respectively, allows for direct connection of terminals 234 and 236 to an
electrical power
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source on a conventional two-terminal receptacle stovetop, cooktop, or range
appliance without
requiring a 4 terminal-to-2-terminal adaptor or an appliance with 4 terminal
receptacles.
[0098]
Terminal bracket 218 supports respective cold legs 219,220,221,222 and is
configured to stabilize the inner and outer heating elements 210,212 relative
to one another. .
Terminal bracket 218 may be positioned somewhat near the terminal end of cold
legs
219,220,221,222 along the sheathed portion of cold legs 219,220,221,222.
Terminal bracket
218 may include apertures, cutouts, grooves, straps, or other similar features
to maintain
position of each respective cold leg 219,220,221,222 relative to one another
while supporting
each of the cold legs 219,220,221,222 in space. Terminal bracket 218 may be
configured to
have a close fit or an interference fit with the outer perimeter of the cold
legs 219,220,221,222.
[0099] In
the embodiment shown in the figures, terminal bracket 218 includes a pair of
apertures with peripheral walls that approximate the shape of an outer profile
of the numeral "8,"
or alternatively, a symmetric peanut shell, having two cylindrical openings
and a necked-down
portion therebetween. The opening that lies in the necked-down portion is
smaller than the
diameter of the sheathed end of the cold legs 219,220,221,222 when the cold
legs are secured
to the bracket 218. The sheathed end of the cold legs 219,220,221,222 may be
slightly tapered
to allow the terminal bracket 218 during assembly to slide onto and wedge
against the cold legs
219,220,221,222. The apertures in the bracket 218 may be sized to snuggly fit
the diameter
along any portion of cold legs 219,220,221,222 near the terminal end. In other
embodiments,
the geometry and/or manner of securing bracket 218 to cold legs
219,220,221,222 may be
different without departing from the scope of the instant disclosure.
[00100] Terminal bracket 218 may be configured from an electrically conductive
material,
such as a metal. Terminal bracket 218 may be configured from a thermally
resistant material.
Terminal bracket 218 may be used to electrically ground electric heating
element 200. Terminal
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bracket 218 may be formed from a stamping, a forging, a casting, a machined
article, a 3-D
printed article, or any other suitable manufacturing method.
[00101]
Spider bracket 217 is configured to support coiled portions 223,224 of the
inner and
outer heating elements 210,212, respectively, relative to one another. Spider
bracket 217 may
be configured with three legs arranged at approximately equal angles with
respect to one
another from a central location, as shown in the figures, or in any other
quantity of legs, shape
or configuration to support the inner and outer heating elements 210,212.
Spider bracket 217
may include upwardly extending protrusions 246 on each leg so as to restrain
and/or help
maintain position of one or more portions of coiled portions 223,224 relative
to spider bracket
217. In other embodiments, spider bracket 217 may include recessed receptacles
formed in
each leg to accomplish this purpose.
[00102]
Heating elements 210,212 may include a tubular sheathed configuration. The
cross
sectional profile of heating elements 210,212 may include a generally
trapezoidal shape with a
flat top surface, downwardly sloped and opposed side walls, and a curved
bottom wall
positioned opposite the flat top surface and joined to the opposed side walls.
A relatively small
transitional radius may exist between the each of the side walls and the top
flat surface. In
other embodiments, the cross sectional profile of heating elements 210,212 may
have any
shape.
[00103] Electric heating element 200 may be controlled via conventional user
commands,
such as by a user interface including, for example, an analog, digital or
virtual dial, knob, button,
or device. Both heating elements 210,212 are energized and de-energized at the
same time via
the user interface to provide increased heat output over a conventional,
single coil design.
[00104]
Figs. 21-33 illustrate an embodiment of a dual coil electric heating element
250
comprising temperature sensor 265, electrically resistive inner heating
element 260, electrically
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resistive outer heating element 262, spider bracket 267, terminal bracket 268,
and compact
terminal portion 255. Compact terminal portion 255 enables easy
interchangeability with
conventional heating elements having a twin-terminal design while providing
the advantage of
increased wattage over a conventional, single coil electric heating element.
To enable adaptor-
free installation into conventional twin-terminal receptacles, which would be
required if the
electric heating element is configured with four terminals like that shown in
Figs. 1-9, compact
terminal portion 255 of electric heating element 250 conveniently bundles
respective inner and
outer positive and negative terminals together to form a single pair of
terminals for insertion into
a conventional two-terminal heating element receptacle. Heating element 250
includes the
added advantage of arranging temperature sensor 265 more centrally, when
viewing a top plan
view of heating element 250, to provide additional clearance between
temperature sensor 265
and a drip pan that may be positioned in proximity to heating element 250
during use.
[00105]
Inner heating element 260 includes cold leg 269, cold leg 271, and coiled
portion
273. Outer heating element 262 includes cold leg 270, cold leg 272, and coiled
portion 274.
The respective cold legs 269,270,271,272 are configured to not generate heat
when the
respective heating elements 260,262 are electrically energized. The respective
coiled portions
273,274 are configured to generate heat when the respective heating elements
260,262 are
electrically energized. The respective coiled portions 273,274 of the
respective heating
elements 260,262 lie in the same plane and in a generally concentric,
counterclockwise spiral
around a common center. More specifically, the coiled portion 274 of outer
heating element 262
lies in a generally concentric, counterclockwise spiral around the coiled
portion 273 of the inner
heating element 260, and coiled portion 273 of the inner heating element 260
lies in a generally
concentric, counterclockwise spiral around a center location that is common to
both the outer
heating element 262 and the inner heating element 260. In other embodiments,
the coiled
portions 273,274 may lie in a generally clockwise arrangement.
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[00106] As shown in the figures, the end portions of cold legs 269,270,271,272
are arranged
in close proximity to one another to form a compact arrangement from which a
pair of terminals
284,286 extend generally parallel to one another for connecting to an
electrical power source.
More specifically, as shown in Fig. 23, the end portion of cold leg 269 of
inner heating element
260 is positioned generally beneath the end portion of cold leg 272 of outer
heating element
262. As shown in Fig. 23, to more centrally position temperature sensor 265
and provide
maximum side-to-side clearance with a drip pan that could be positioned
underneath electric
heating element 250, the end portion of cold leg 271 of inner heating element
260 is positioned
between the end portion of cold leg 270 of outer heating element 262 and the
end portion of
cold leg 272 of outer heating element 262. In addition, to provide maximum top-
to-bottom
clearance with a drip pan while managing the proximity of temperature sensor
265 to inner
heating element 260 and outer heating element 262, end portion of cold leg 271
may be
positioned slightly higher than end portions 272,270, as shown in Fig. 23.
[00107] To connect heating element 250 to an electrical power source, inner
heating element
260 includes electrical terminals 281,283 extending from respective end
portions of cold legs
271,269, and outer heating element 262 includes electrical terminals 284,286
extending from
respective end portions of cold legs 272,270. As best shown in Fig. 32,
terminal 281 is
connected to terminal 286 and terminal 283 is connected to terminal 284. In
this embodiment,
the electrical conductor 279 of terminal 281 turns or is bent towards, and is
joined by brazing or
soldering to or otherwise joined with, the electrical conductor 278 of
terminal 266 at a location
some distance away from the end of terminal 286. The electrical conductor 277
of terminal 283
turns or is bent towards, and is joined by brazing or soldering to or
otherwise joined with, the
electrical conductor 276 of terminal 284 at a location some distance away from
the end of
terminal 284. In other embodiments, terminals 281 and 283 may be jumpered to
terminals 286
and 284, respectively. Positioning and connecting the conductors 277 and 279
to conductors
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276 and 278, respectively, allows for direct connection of terminals 284 and
286 to an electrical
power source on a conventional two-terminal receptacle stovetop, cooktop, or
range appliance
without requiring a 4 terminal-to-2-terminal adaptor or an appliance with 4
terminal receptacles.
[00108] Terminal bracket 268 supports respective cold legs 269,270,271,272 and
is
configured to stabilize the inner and outer heating elements 260,262 relative
to one another.
Terminal bracket 268 may be positioned somewhat near the terminal end of cold
legs
269,270,271,272 along the sheathed portion of cold legs 269,270,271,272.
Terminal bracket
268 may include apertures, cutouts, grooves, straps, or other similar features
to maintain
position of each respective cold leg 269,270,271,272 relative to one another
while supporting
each of the cold legs 269,270,271,272 in space. Terminal bracket 268 may be
configured to
have a close fit or an interference fit with the outer perimeter of the cold
legs 269,270,271,272.
[00109] In the embodiment shown in the figures, the end 287 of the cold legs
269,270,271,272 nearest terminals 284,286 may be slightly tapered to allow the
terminal
bracket 268 to slide onto and wedge against the cold legs 269,270,271,272
during assembly.
The apertures in the bracket 268 may be sized to snuggly fit the diameter
along any portion of
cold legs 269,270,271,272 near the terminal end. In other embodiments, the
geometry and/or
manner of securing bracket 268 to cold legs 269,270,271,272 may be different
without departing
from the scope of the instant disclosure. Cold legs 269,270,271,272 may be
brazed or welded
to terminal bracket 268. Terminal bracket 268 may be crimped to each of the
cold legs
269,270,271,272.
[00110] Cold legs 269,270,271,272 may be configured with conductors
276,278,277,279
covered with silicone insulation 282, which is covered by sheath 285. To
transition cold legs
269,270,271,272 to the heated portions of inner heating element 260 and outer
heating element
262, conductors 276,278,277,279 may be connected, such as by welding, to
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resistive wire that lies coiled inside a densely packed volume of magnesium
oxide powder, all of
which is covered by sheath 285. This form of transitioning from the cold legs
to the heated
portions may be utilized in any of the dual coil electric heating elements
100,150,200,250
described herein.
[00111]
Terminal bracket 268 may be configured from an electrically conductive
material,
such as a metal. Terminal bracket 268 may be configured from a thermally
resistant material.
Terminal bracket 268 may be used to electrically ground electric heating
element 250. Terminal
bracket 268 may be formed from a stamping, a forging, a casting, a machined
article, a 3-D
printed article, or any other suitable manufacturing method.
[00112] Spider bracket 267 is configured to support coiled portions 273,274 of
the respective
inner and outer heating elements 260,262 relative to one another. Spider
bracket 267 may be
configured with three legs arranged at approximately equal angles with respect
to one another
from a central location, as shown in the figures, or in any other quantity of
legs, shape or
configuration to support the inner and outer heating elements 260,262. Spider
bracket 267 may
include upwardly extending protrusions 296 on each leg so as to restrain
and/or help maintain
position of one or more portions of coiled portions 273,274 relative to spider
bracket 267. In
other embodiments, spider bracket 267 may include recessed receptacles formed
in each leg to
accomplish this purpose.
[00113]
Heating elements 260,262 may include a tubular sheathed configuration. The
cross
sectional profile of heating elements 260,262 may include a generally
trapezoidal shape with a
flat top surface, downwardly sloped and opposed side walls, and a curved
bottom wall
positioned opposite the flat top surface and joined to the opposed side walls.
A relatively small
transitional radius may exist between the each of the side walls and the top
flat surface. In
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other embodiments, the cross sectional profile of heating elements 260,262 may
have any
shape.
[00114] One or more temperature sensors 265 may be connected to either or both
of heating
elements 260,262 for sensing the temperature of a cooking utensil positioned
on the top flat
surface of heating elements 260,262. To minimize erroneous temperature
readings and
damage from excessive exposure to heat generated from heating elements 260,122
and/or
liquids associated with items to be cooked in the utensil, the one or more
temperature sensors
265 may be positioned along cold leg 271 of inner heating element 260, as
shown in the figures,
for maximum clearance between housing 280 and a drip pan positioned in
proximity with
heating element 250. The one or more temperature sensors 265 may include a
thermocouple,
a thermistor, electrical switch 142 (described above), or a relatively small
thermostat comprising
a relatively small bimetal material, which in turn allows for quicker reset of
the switch (discussed
below) for improved cooking performance. By positioning one or more
temperature sensors 265
along cold leg 271 of inner heating element 260, selective on/off control of
the inner coiled
portion 273 while maintaining continuous heating of the outer heating element
262 improves
cooking performance while minimizing overcooking.
[00115] In some embodiments, the one or more temperature sensors 265 comprises
a
bimetal thermostat positioned along a cold leg, such as cold leg 271 (as
shown, for example, in
Fig. 21). The thermostat may selectively control delivery of electrical
current to inner heating
element 260. The bimetal material of the thermostat may be configured to open
an electrical
circuit upon reaching a desired, predetermined temperature thereby shutting
off power to inner
heating element 260. For example, when a thermostat is positioned along cold
leg 271,
electrical current to the inner coiled portion 273 is ceased when the bimetal
material of the
thermostat opens the circuit while electrical current to the outer coiled
portion 274 continues at
its maximum or other desired setting. As illustrated in the figures, inner
heating element 260 is
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wired in parallel with outer heating element 262 to allow outer coiled portion
274 to remain
electrically energized when electrical current to inner coiled portion 273 is
ceased.
[00116] Depending on available space and size of the thermostat and/or
thermostat housing,
a thermostat may be positioned along a cold leg of the outer heating element
262, such as cold
leg 270 to provide selective on/off control of the outer coiled portion 274
while maintaining
continuous heating of the inner heating element 260. In embodiments when a
thermostat is
positioned along cold leg 270, for example, electrical current to the outer
coiled portion 274 is
ceased when the bimetal material of the thermostat opens the circuit while
electrical current to
the inner coiled portion 273 continues at its maximum or other desired
setting.
[00117]
Upon ceasing the flow of electrical current, the inner heating element 260 (or
the
outer heating element 262 as the case may be) and the bimetal material of the
thermostat will
tend to cool due to reduced heat being generated from the heating element 250.
When the
bimetal material of the thermostat is cooled to a desired, predetermined
temperature, the
thermostat may "reset" by closing the circuit to allow electricity to flow
again to the inner heating
element 260. How quickly the thermostat resets and the modulation of heat
radiating from
heating element 250 may be a function of various factors, including the
thermostat size, the
configuration and extent of thermostat shielding (e.g., from the housing
described below),
protective barriers or coatings applied to internal or external surfaces to,
for example, thermal
shielding (e.g., coating or lining a thermostat housing with a reflective or a
nonreflective material
or a colored paint), and relative position of the thermostat along a cold leg
with respect to the
radiant heat from the inner heating element 260 and the outer heating element
262. As
described above, some embodiments may include a paint or a coating applied to
a surface of
the thermostat or to a surface of the enclosure that houses the thermostat,
such as housing
280, to control the amount or the rate of exposure of the thermostat to heat
from the inner
heating element 260 and/or the outer heating element 262.
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[00118] In other embodiments, the one or more temperature sensors 265 may
include or be
coupled to an electrical switch, such as switch 142 described above to turn on
and/or turn off
electrical current to a designated inner heating element 260 or outer heating
element 262 or
both. A controller, such as controller 140 described above, comprising a
microprocessor and
memory may be coupled to the one or more temperature sensors 265 and to the
switch 142,
and upon receiving a signal and/or sensor data from the one or more
temperature sensors 265,
may command the switch 142 to open and/or close to turn on and/or turn off
electrical current to
a designated inner heating element 260 or outer heating element 262 or both.
The signal
and/or sensor data may be a sensed temperature or interpreted as a sensed
temperature by the
controller 140. The features and functionality of controller 140 with respect
to the operation of
electric heating element 250 may be the same as described above for electric
heating element
100.
[00119]
Electric heating element 250 may include a protective housing 280 for housing
and
protecting the one or more temperature sensors 265 from dust, debris, food,
liquids, and
excessive or undesirable temperatures, and for enabling optimum performance of
the one or
more temperature sensors 265 in a smaller package. Housing 280 may be
configured with a
top portion 288 and a bottom portion 289 that when brought together form
housing 280. As best
shown in Fig. 31, top portion 288 may include a top wall 290 and two opposed
end walls 291, all
formed from sheet metal in this embodiment. In other embodiments, housing 280
may be made
from other heat resistant material(s). Each of the two opposed end walls 291
include an
aperture sized to snugly fit opposing ends of cold leg 271 therethrough, which
opposing ends
may be tapered to assist assembly. As shown in the embodiment of Fig. 28,
temperature
sensor 265 comprising a bimetal thermostat is positioned with its bimetal disc
in close proximity
to top wall 290. The cover of the thermostat may be connected to top wall 290
by, for example,
spot welding the thermostat cover to the top wall 290. Bottom portion 289 may
include a bottom
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wall 291, two opposed side walls 292, and two opposed end walls 293. As shown
in the
embodiment of Fig. 29, each of the two opposed end walls 293 include a slot
294 to slide over
opposing ends of cold leg 271. Respective end walls 293 of bottom portion 289
are configured
to lie adjacent to respective end walls 291 of top portion 288. When
positioned adjacently
together, such as in a nested fashion, top portion 288 and bottom portion 289
may be welded or
otherwise joined together.
[00120] In some embodiments, the one or more temperature sensors 265 may be
housed in
the same housing as switch 142, such as housing 280. In other embodiments,
switch 142 may
be positioned away from housing 280, such as somewhere in or on the appliance
(e.g., stove)
itself. Similarly, controller 140 may be positioned away from heat generated
by electric heating
element 250, such as somewhere in or on the appliance (e.g., stove) itself.
[00121] In
one embodiment, as best shown in Figs. 21, 22 and 26, the one or more
temperature sensors 265 and its protective housing 280 are positioned along
the cold leg 271
and underneath the inner coiled portion 273 and the outer coiled portion 274
in proximity to
inner coiled portion 273. A first end of cold leg 271 extends from the housing
280 and
terminates at terminal 286 via terminal 281 and conductors 279,278. A second
end of cold leg
271 extends from housing 280 toward the center of the electric heating element
250 and below
spider bracket 267. The second end turns upwardly a short distance after
exiting housing 180
and then turns horizontally to transition to inner coiled portion 273 of inner
heating element 260.
This arrangement permits a relatively small radius for the first
counterclockwise turn of inner
coiled portion 273 of inner heating element 260, which minimizes the size of
any unheated area
in the center portion of electric heating element 250. As described above, the
one or more
temperature sensors 265, whether or not housed in an enclosure, such as
housing 280, may be
positioned above the drip pan that may be positioned under electric heating
element 250 on a
stovetop or similar appliance.
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[00122] Electric heating element 250 may be controlled via conventional user
commands,
such as by a user interface including, for example, an analog, digital or
virtual dial, knob, button,
or device. Both heating elements 260,262 are energized and de-energized at the
same time via
the user interface to provide increased heat output over a conventional,
single coil design.
[00123] Any of the features described with reference to Figs. 1-33 may be
combined into a
single embodiment, even if not simultaneously shown in a single drawing
figure. In addition,
one of ordinary skill would appreciate that the teachings of the instant
disclosure include electric
heating elements with more than two heating coils.
[00124] While specific embodiments have been described in detail, it will be
appreciated by
those skilled in the art that various modifications and alternatives to those
details could be
developed in light of the overall teachings of the disclosure. Accordingly,
the disclosure herein
is meant to be illustrative only and not limiting as to its scope and should
be given the full
breadth of the appended claims and any equivalents thereof.
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