Cooktop appliance and temperature switch
10499459 ยท 2019-12-03
Assignee
Inventors
Cpc classification
International classification
Abstract
A cooktop appliance is generally provided herein. The cooktop appliance may include a cooktop panel, an electric heating element, a ferromagnetic tab, and a magnetic temperature switch. The electric heating element may be positioned at the cooktop panel. The electric heating element may include a first terminal and a second terminal. The ferromagnetic tab may be in thermal engagement with the electric heating element. The magnetic temperature switch may be positioned in selective magnetic engagement with the ferromagnetic tab. The magnetic temperature switch may be electrically connected in series with the second terminal and operable to restrict a voltage to the electric heating element above a predetermined temperature.
Claims
1. A cooktop appliance comprising: a cooktop panel; an electric heating element positioned at the cooktop panel, the electric heating element including a first terminal and a second terminal; a ferromagnetic tab in stationary, conductive, thermal engagement with the electric heating element; and a magnetic temperature switch positioned in selective magnetic engagement with the ferromagnetic tab, the magnetic temperature switch being electrically connected in series with the second terminal and operable to restrict a voltage to the electric heating element above a predetermined temperature, wherein the magnetic switch comprises a retainer bracket disposed below the ferromagnetic tab, a switch body mounted to the retainer bracket, a magnetic element housed within the switch body radially outward from the retainer bracket, an articulating connection plate fixed to the magnetic element within the switch body, and a mechanical spring motivating the connection plate and magnetic element radially outward away from the ferromagnetic tab, and wherein the ferromagnetic tab is positioned below the heating element and received within the retainer bracket.
2. The cooktop appliance of claim 1, wherein the electric heating element comprises a first resistive coil, the first resistive coil comprising the first terminal and the second terminal.
3. The cooktop appliance of claim 2, wherein the electric heating element comprises a second resistive coil, the second resistive coil comprising a third terminal and a fourth terminal.
4. The cooktop appliance of claim 3, further comprising: a first electrical conduit connected in series with the first terminal and the third terminal, a second electrical conduit connected in series with the second terminal and the temperature switch, and a third electrical conduit connected in series with the fourth terminal.
5. The cooktop appliance of claim 1, wherein the predetermined temperature is equal to a Curie temperature of the ferromagnetic tab.
6. The cooktop appliance of claim 5, wherein the Curie temperature of the ferromagnetic tab is above 360 Celsius.
7. The cooktop appliance of claim 6, wherein the magnetic switch includes a first prong and a second prong, and wherein the connection plate is disposed in series between the first prong and the second prong.
8. The cooktop appliance of claim 7, wherein the connection plate is disposed in conductive engagement with the first and second prongs in the first position, and wherein the connection plate is spaced away from the first and second prongs in the second position to prevent conduction therebetween.
9. A cooktop appliance comprising: a cooktop panel; an electric heating element positioned at the cooktop panel; an element frame supporting the electric heating element, the element frame being positioned below the electric heating element; a ferromagnetic tab extending from the element frame in stationary, conductive, thermal engagement with the electric heating element; and a magnetic temperature switch positioned in selective magnetic engagement with the ferromagnetic tab, the magnetic temperature switch being operable to restrict a voltage to the electric heating element above a predetermined temperature, wherein the magnetic switch comprises a retainer bracket disposed below the ferromagnetic tab, a switch body mounted to the retainer bracket, a magnetic element housed within the switch body radially outward from the retainer bracket, an articulating connection plate fixed to the magnetic element within the switch body, and a mechanical spring motivating the connection plate and magnetic element radially outward away from the ferromagnetic tab, and wherein the ferromagnetic tab is positioned below the heating element and received within the retainer bracket.
10. The cooktop appliance of claim 9, wherein the electric heating element comprises a first resistive coil.
11. The cooktop appliance of claim 10, wherein the temperature switch is electrically connected in series with the first resistive coil.
12. The cooktop appliance of claim 10, wherein the electric heating element further comprises a second resistive coil.
13. The cooktop appliance of claim 12, wherein the temperature switch is electrically connected in series with the first resistive coil and electrically isolated from the second resistive coil.
14. The cooktop appliance of claim 9, wherein the predetermined temperature is equal to a Curie temperature of the ferromagnetic tab.
15. The cooktop appliance of claim 14, wherein the Curie temperature of the ferromagnetic tab is above 360 Celsius.
16. The cooktop appliance of claim 9, wherein the magnetic switch includes a first prong and a second prong, and wherein the connection plate is disposed in series between the first prong and the second prong.
17. The cooktop appliance of claim 16, wherein the connection plate is disposed in conductive engagement with the first and second prongs in the first position, and wherein the connection plate is spaced away from the first and second prongs in the second position to prevent conduction therebetween.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.
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DETAILED DESCRIPTION
(11) Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
(12) Generally, the present disclosure provides a cooktop appliance that includes at least one heating assembly. The heating assembly may have one or more electric heating elements and a ferromagnetic tab that can receive heat transferred from the electric heating element(s). A temperature switch may be provided, including a portion that can be magnetically attracted to the ferromagnetic tab. When the ferromagnetic tab exceeds a certain temperature, the temperature switch may lose magnetic attraction and restrict or cut off a voltage to one or more of the electric heating elements. If and/or when the temperature falls by a sufficient amount, the temperature switch may regain magnetic attraction and again permit or direct the voltage to the electric heating element(s).
(13) Turning now to the figures,
(14) Cooktop panel 20 of cooktop appliance 10 includes one or more heating assemblies 22 having at least one heat zone 23. Cooktop panel 20 may be constructed of any suitable material, e.g., a ceramic, enameled steel, or stainless steel. As shown in
(15) Exemplary embodiments include a user interface 16 having one or more control inputs 18 permits a user to make selections for cooking of food items using heating assemblies 22 and/or the cooking chamber. As an example, a user may manipulate one or more control inputs 18 to select, e.g., a power or heat output setting for each heating assembly 22. The selected heat output setting of heating assembly 22 affects the heat transferred to cooking utensil 12 positioned on heating assembly 22. Although shown on a backsplash or back panel of cooktop appliance 10, user interface 16 may be positioned in any suitable location, e.g., along a front edge of the appliance 10. Control inputs 18 may include one or more buttons, knobs, or touch screens, as well as combinations thereof.
(16) Some embodiments further include a controller 32 operably connected, e.g., electrically coupled, to user interface 16 and/or control inputs 18. Generally, operation of cooking appliance 10, including heating assemblies 22, may be controlled by controller 32. In some embodiments, controller 32 is a processing device and may include a microprocessor or other device that is in operable communication with components of appliance 10, such as heating assembly 22. Controller 32 may include a memory and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with a selected heating level, operation, or cooking cycle. The memory may represent random access memory such as DRAM, and/or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. Alternatively, controller 32 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software.
(17) Control inputs 18 and other components of cooking appliance 10 may be in communication with (e.g., electrically coupled to) controller 32 via one or more signal lines or shared communication busses. Heating assembly 22 may be operably connected to controller, e.g., at one or more respective terminal pairs.
(18) Operation of heating assembly 22 may be regulated such that the temperature or heat output of heating assembly 22 corresponds to a temperate or heat output selected by a user of cooktop appliance 10 For example, one or more electric heating elements 21 (
(19) As illustrated in
(20) In some embodiments, such as the example embodiment of
(21) A first terminal 46 and a second terminal 48 may be provided for heating element 21. Specifically, first terminal 46 and second terminal 48 may be electrically coupled to heating element 21. An electrical current may be transmitted to a first resistive coil 24 at the terminals 46, 48. When a voltage differential is applied across first and second terminals 46, 48 of first resistive coil 24, a temperature of electric heating element 21 increases. First resistive coil 24 may be a CALROD coil in certain exemplary embodiments.
(22) A temperature switch 36 is generally provided as a safety mechanism separate from the controller 32. In some embodiments, temperature switch 36 is positioned proximate to electric heating element 21, as will be described in detail below. Generally, temperature switch 36 may be positioned such that a temperature adjacent to temperature switch 36 corresponds to a temperature of heating assembly 22 or cooking utensil 12 (
(23) Temperature switch 36 may generally be operable to restrict a voltage to electric heating element 21 above a predetermined temperature. Specifically, temperature switch 36 may actuate from a first, e.g., activated, state (
(24) A first electrical conduit 42 is coupled to first terminal 46 of electric heating element 21. First electrical conduit 42 is configured for operating at a first voltage, L1, with respect to ground. Thus, first electrical conduit 42 may be coupled or connected to a first voltage source operating at the first voltage L1 with respect to ground. Cooktop appliance 10 also includes a second electrical conduit 44 configured for operating at a second voltage, L2, with respect to ground. Thus, second electrical conduit 44 may be coupled or connected to a second voltage source operating at the second voltage L2 with respect to ground. The first and second electrical conduits 42, 44 may be any suitable electrical conduits, such as wires, cables, etc.
(25) The first voltage L1 and the second voltage L2 have opposite polarities. In addition, a magnitude of the first voltage L1 with respect to ground may be about equal to a magnitude the second voltage L2 with respect to ground. As used herein, the term about corresponds to within ten volts of a stated voltage when used in the context of voltage. As an example, the magnitude of the first and second voltages L1, L2 may be about one hundred twenty volts with respect to ground. Thus, e.g., first electrical conduit 42 may be coupled to one phase of a two hundred forty volt household electrical supply, and second electrical conduit 44 may be coupled to the second phase of the two hundred forty volt household electrical supply.
(26) Temperature switch 36 may be connected to second conduit 44 in series between second terminal 48 and second voltage L2, e.g., an electrical supply for L2. As described above, temperature switch 36 may selectively adjust between a first and second state. Accordingly, temperature switch 36 may selectively couple or connect second terminal 48 to second electrical conduit 44. By selectively coupling or connecting the second terminal 48 of electric heating element 21 to second electrical conduit 44, a power output of electric heating element 21 may be regulated with temperature switch 36.
(27) As illustrated in
(28) A first terminal 46 and a second terminal 48 may be provided for first resistive coil 24. A third terminal 52 and a fourth terminal 54 may be provided for second resistive coil 26. An electrical current may be transmitted to each resistive coil 24, 26 at the terminals 46, 48, 52, 54. When a voltage differential is applied across first and second terminals 46, 48 of electrical first coil 24, a temperature of electric heating element 21 increases. Additionally or alternatively, when a voltage differential is applied across third and fourth terminals 52, 54, a temperature of electric heating element 21 increases. First resistive coil 24 and/or second resistive coil 26 may be a CALROD coil in certain exemplary embodiments.
(29) As noted above, temperature switch 36 may be positioned such that a temperature of temperature switch 36 corresponds to a temperature of heating assembly 22 or cooking utensil 12 (
(30) Temperature switch 36 may generally be operable to restrict a voltage to first resistive coil 24 and/or second resistive coil 26 above a predetermined temperature. Specifically, temperature switch 36 may actuate from a first, e.g., activated, state (
(31) A first electrical conduit 42 is coupled to first terminal 46 of first resistive coil 24. In some embodiments, first electrical conduit 42 may be further coupled to third terminal 52 of second resistive coil 26, e.g., via a common conductive coupler connecting first terminal 48 and third terminal 52. Optionally, first resistive coil 24 and second resistive coil 26 may be coupled in parallel, as illustrated. First electrical conduit 42 is configured for operating at a first voltage, L1, with respect to ground. Thus, first electrical conduit 42 may be coupled or connected to a first voltage source operating at the first voltage L1 with respect to ground. A pair of second electrical conduits, e.g., a primary second conduit 44A and a matched second conduit 44B, each configured for operating at a second voltage, L2, with respect to ground. As shown, each second electrical conduit 44A, 44B is provided in parallel. Thus, each second electrical conduit 44A, 44B may be coupled or connected to a second voltage source operating at the second voltage L2 with respect to ground. The first and second electrical conduits 42, 44A, 44B may be any suitable electrical conduits, such as wires, cables, etc.
(32) The first voltage L1 and the second voltage L2 have opposite polarities. In addition, a magnitude of the first voltage L1 with respect to ground may be about equal to a magnitude the second voltage L2 with respect to ground. As an example, the magnitude of the first and second voltages L1, L2 may be about one hundred and twenty volts with respect to ground. Thus, e.g., first electrical conduit 42 may be coupled to one phase of a two-hundred and forty volt household electrical supply, and each of second electrical conduits 44A, 44B may be coupled to the second phase of the two-hundred and forty volt household electrical supply.
(33) Temperature switch 36 may be connected to at least one of second conduits 44A, 44B (e.g., primary second conduit 44A) in series between second terminal 48 and second voltage L2. As described above, temperature switch 36 may selectively adjust between a first and second state. Accordingly, temperature switch 36 may selectively couple or connect second terminal 48 to the one of second electrical conduits 44A. As shown, temperature switch 36 is electrically connected in series with first resistive coil 24. By selectively coupling or connecting the second terminal 48 of electric heating element 21 to second electrical conduit 44A, a power output of electric heating element 21 may be regulated with temperature switch 36. Temperature switch 36 may be electrically isolated from second resistive coil 26. For instance, as provided in the exemplary embodiments of
(34) Turning to
(35) In some embodiments, connection plate 108 is fixed to a rigid pin 112 extending from magnetic element 110. As magnetic element 110 moves, so does connection plate 108 and rigid pin 112. Optionally, rigid pin 112 may extend through a separation wall 114 of switch body 102. A first chamber 116 may be defined on one side of separation wall 114, while a second chamber 118 is defined on the opposite side of separation wall 114. For instance, magnetic element 110 may be disposed within first chamber 116, while connection plate 108 is disposed within second chamber 118. Rigid pin 112 may extend into both first chamber 116 and second chamber 118 through a channel 120 defined by separation wall 114.
(36) A mechanical spring 122 may attach to connection plate 108, e.g., via rigid pin 112. Mechanical spring 122 may be configured to bias or motivate connection plate 108 within switch body 102, e.g., away from second chamber 118. In certain embodiments, mechanical spring 122 is a tension spring extending between two opposite ends 126, 128. One end 126 may be fixed to rigid pin 112, while the opposite end 128 is fixed to a segment of switch body 102. It should be noted that although mechanical spring 122 is illustrated as a tension spring, alternative embodiments may be a compression spring, diaphragm spring, cantilever spring, leaf spring, or another suitable embodiment configured to bias connection plate 108 as described.
(37) A ferromagnetic tab 124 may be in selective magnetic engagement with (e.g., magnetically attracted to) magnetic temperature switch 36. Specifically, ferromagnetic tab 124 may be in selective magnetic engagement with magnetic element 110. As shown, ferromagnetic tab 124 may be positioned proximate to magnetic temperature switch 36. When assembled, magnetic element 110 is thus generally biased toward ferromagnetic tab 124. However, once ferromagnetic tab 124 is heated above a Curie temperature thereof (e.g., via heat conducted from heating assembly 22 (
(38) Ferromagnetic tab 124 may be formed from one or more suitable ferromagnetic materials. The material of ferromagnetic tab 124 may be determined according to a desired Curie temperature. Thus, the materials of ferromagnetic tab 124 may be selected to such that the Curie temperature of ferromagnetic tab 124 corresponds to or defines the threshold temperature. In some embodiments, the ferromagnetic tab 124 may be formed from nickel or one or more nickel alloys. Advantageously, temperature switch 36 may have a higher predetermined temperature than possible with existing (e.g., bimetal switch) systems.
(39) Turning to
(40) A drip pan 64 may be attached, e.g., removably attached, to panel 20 below electric heating element 21. Mounting element 30 may be positioned between drip pan 64 and heating element 21. In some embodiments, drip pan 64 includes a support lip 66 extending along circumferentially outward to rest on a top surface of panel 20, e.g., about hole 68. When mounted, a concave sidewall 70 may extend below panel 20. For example, a portion of concave sidewall 70 may extend through hole 68 from support lip 66. Concave sidewall 70 may include an inner surface 72 facing the hole 68 and/or electric heating element 21. An outer surface 74 of concave sidewall 70 may be positioned opposite inner surface 72 to face away from hole 68 and/or electric heating element 21.
(41) Some embodiments include temperature switch 36 mounted below cooktop panel 20 along the vertical direction V. Additionally or alternatively, temperature switch 36 is positioned below heating element 21. Advantageously, the temperature switch 36 may be positioned outside of a potential pool zone where water (e.g., spilled over from a utensil positioned on heating element 21) may collect within drip pan 64. One or more mechanical fasteners (not pictured) or adhesives may fix temperature switch 36 to a base wall 78 extending below cooktop panel 20 (e.g., between the cooking cavity and door 14 (
(42) Temperature switch 36 may include a retainer bracket 134 to receive ferromagnetic tab 124. A support plate 136 of retainer bracket 134 may be positioned below ferromagnetic tab 124, e.g., in support thereof, while resilient fingers 138 extend above support plate 136 on opposite sides of ferromagnetic tab 124. When assembled, resilient fingers 138 may align ferromagnetic tab 124 relative to support plate 136. Optionally, resilient fingers 138 may form a spring clip holding ferromagnetic tab 124 to retainer bracket 134. Retainer bracket 134 may generally hold ferromagnetic tab 124 below heating element 21. In some such embodiments, retainer bracket 134 is positioned radially inward from magnetic element 110.
(43) Ferromagnetic tab 124 is generally provided in thermal engagement with heating element 21. For instance, ferromagnetic tab 124 may contact mounting element 30 to receive heat generated from heating element 21, e.g., such that the temperature at ferromagnetic tab generally reflects the temperature at heating element 21. In some such embodiments, ferromagnetic tab 124 is integral with mounting element 30 as a singular unitary feature. In alternative embodiments, ferromagnetic tab 124 is a discrete separable component in direct contact with mounting element 30. During operations, heat may be conducted to ferromagnetic tab 124 from heating element 21.
(44) In some embodiments, a slot 76 may be defined in drip pan 64 to receive ferromagnetic tab 124. When assembled, ferromagnetic tab 124 may extend from mounting element 30, through slot 76, and to retainer bracket 134 of temperature switch 36.
(45) Returning to
(46) As illustrated, in the first position of
(47) By contrast, in the second position of
(48) As described above, temperature switch 36 may alternate between the first position and the second position according to the magnetism between ferromagnetic tab 124 and magnetic element 110. Temperature switch 36 may rapidly transition from the first position to the second position when the temperature of ferromagnetic tab 124 is raised above the Curie temperature thereof. Moreover, temperature switch 36 may rapidly transition from the second position to the first position when the temperature of ferromagnetic tab 124 is lowered below the Curie temperature. Advantageously, the system temperature switch 36 may rapidly transition from an activated state to a deactivated state (and vice versa) while reducing the potential for nuisance tripping (e.g., in comparison to a bimetal switch system).
(49) This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.