CA1172677A - Range temperature protection - Google Patents
Range temperature protectionInfo
- Publication number
- CA1172677A CA1172677A CA000408931A CA408931A CA1172677A CA 1172677 A CA1172677 A CA 1172677A CA 000408931 A CA000408931 A CA 000408931A CA 408931 A CA408931 A CA 408931A CA 1172677 A CA1172677 A CA 1172677A
- Authority
- CA
- Canada
- Prior art keywords
- temperature
- module
- heating elements
- switches
- control unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24C—DOMESTIC STOVES OR RANGES ; DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION
- F24C7/00—Stoves or ranges heated by electric energy
- F24C7/08—Arrangement or mounting of control or safety devices
Abstract
RANGE TEMPERATURE PROTECTION
ABSTRACT OF THE DISCLOSURE
A domestic range of the electric type includes a cooking platform providing a plurality of "burner" locations constituted by pancake-shaped surface heating elements formed of spirally wound resistance wire. An elongated boxlike con-trol unit extends upwardly from and across the back edge of the cooking platform. An oven chamber of the pyrolytic self-cleaning type is located below the range platform and includes radiant-type heating elements also formed of resis-tance wire. A heat-sink-mounted electronic module located within the control unit is protected from damaging high tem-peratures caused by improper operation of the range by a pair of normally closed temperature-sensitive bimetal actuated switches mounted to the module heat sink, the switches being connected in electrical series relationship between the heat-ing elements and their electrical power source.
ABSTRACT OF THE DISCLOSURE
A domestic range of the electric type includes a cooking platform providing a plurality of "burner" locations constituted by pancake-shaped surface heating elements formed of spirally wound resistance wire. An elongated boxlike con-trol unit extends upwardly from and across the back edge of the cooking platform. An oven chamber of the pyrolytic self-cleaning type is located below the range platform and includes radiant-type heating elements also formed of resis-tance wire. A heat-sink-mounted electronic module located within the control unit is protected from damaging high tem-peratures caused by improper operation of the range by a pair of normally closed temperature-sensitive bimetal actuated switches mounted to the module heat sink, the switches being connected in electrical series relationship between the heat-ing elements and their electrical power source.
Description
1 ~ 7~77 RANGE TEMPERA~URE PROTECTION
BACKGROUND OF THE INVENTION
:`
The invention relates in general to thermostatic controls, and in particular to means for protecting a temperature-sensitive electronic module associated with a domestic range employing electric resistance heating elements.
The continuing advance of microelectronics has made possible the computerized control of domestic appliances such as programmable microwave cooking ovens, automatic dish-washers, domestic ranges and the like. The associated inte-grated circuit containing elec~ronic module for accomplishing such computerized microelectri~ control, while continuing to decrease in cost, still constitutes a high cost component of the controlled appliance, and thus mus~ be fully protected from damaging high temperature conditions.
The problem of module temperature control is espe-cially acute in a microcomputer-controlled domestic range having a horizontal cooking platform providing a plurality of resistance wire surface heati;ng elements and a pyrolytic type self-cleaning oven located below the platform, the oven ; including radiant heating elements also formed of resistance wire.
~ In such a range, the electronic control module is ; ~ typically contained within a boxlike control unit extending upwardly from and across the back edge of the cooking plat-form. Where the range is located in a confined area, it may be possible to overheat the module-containing control unit during a high-temperature sel~-cleaning cycle of the oven and/or during i~proper usage of surface heating units in an ~' .
:i 172~7'~
unloaded condition (i.e., without a cooking utensil placed on the energized surface heating element).
To protect the electronic module from damage by high temperatures, means must be provided to limit to a tolerable level an over-temperature condition of the module caused by the energization of one or more of the heating elements.
Such a temperature limiting means must be durable and very reliable, due to the relatively long life expectancy of domestic appliances. Also, such a means must be low in cost due to the competitive nature of the domestic appliance business.
SUMMARY OF T~E INVENTION
The present invention provides, in a domestic range havin~ a radiant-type heating means temperature-regulated by a control unit including an electronic control module, an over-temperature protection means for the control module.
The protection means includes a temperature-sensitive switch means located ~enerally at the site of the control module. The switch means disables at least a portion of the heating means at a predetermined sensed temperature to preclude damage to the module caused by high temperatures generated by the heating means. A metallic heat sink member is provided to which both the switch and the module is fixed. The switch means senses the temperature of the heat sink member portion to which it is fixed.
Preferably, the switch is constituted by a pair of bimetal snap-disc-actuated switches straddling the module, the bimetal switches and the module being mounted to a common heat sink member. The bimetal switches automatically reset when the sensed temperature reaches a tolerable level wherein normal operation of the range is resumed.
BACKGROUND OF THE INVENTION
:`
The invention relates in general to thermostatic controls, and in particular to means for protecting a temperature-sensitive electronic module associated with a domestic range employing electric resistance heating elements.
The continuing advance of microelectronics has made possible the computerized control of domestic appliances such as programmable microwave cooking ovens, automatic dish-washers, domestic ranges and the like. The associated inte-grated circuit containing elec~ronic module for accomplishing such computerized microelectri~ control, while continuing to decrease in cost, still constitutes a high cost component of the controlled appliance, and thus mus~ be fully protected from damaging high temperature conditions.
The problem of module temperature control is espe-cially acute in a microcomputer-controlled domestic range having a horizontal cooking platform providing a plurality of resistance wire surface heati;ng elements and a pyrolytic type self-cleaning oven located below the platform, the oven ; including radiant heating elements also formed of resistance wire.
~ In such a range, the electronic control module is ; ~ typically contained within a boxlike control unit extending upwardly from and across the back edge of the cooking plat-form. Where the range is located in a confined area, it may be possible to overheat the module-containing control unit during a high-temperature sel~-cleaning cycle of the oven and/or during i~proper usage of surface heating units in an ~' .
:i 172~7'~
unloaded condition (i.e., without a cooking utensil placed on the energized surface heating element).
To protect the electronic module from damage by high temperatures, means must be provided to limit to a tolerable level an over-temperature condition of the module caused by the energization of one or more of the heating elements.
Such a temperature limiting means must be durable and very reliable, due to the relatively long life expectancy of domestic appliances. Also, such a means must be low in cost due to the competitive nature of the domestic appliance business.
SUMMARY OF T~E INVENTION
The present invention provides, in a domestic range havin~ a radiant-type heating means temperature-regulated by a control unit including an electronic control module, an over-temperature protection means for the control module.
The protection means includes a temperature-sensitive switch means located ~enerally at the site of the control module. The switch means disables at least a portion of the heating means at a predetermined sensed temperature to preclude damage to the module caused by high temperatures generated by the heating means. A metallic heat sink member is provided to which both the switch and the module is fixed. The switch means senses the temperature of the heat sink member portion to which it is fixed.
Preferably, the switch is constituted by a pair of bimetal snap-disc-actuated switches straddling the module, the bimetal switches and the module being mounted to a common heat sink member. The bimetal switches automatically reset when the sensed temperature reaches a tolerable level wherein normal operation of the range is resumed.
- 2 -cr/
` ~ 17~67~f A fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a domestic range of the electric type incorporating the present invention, the range including an electronic module containing control unit extending upwardly from and across the back of the top hori-zontal cooking platform of the range;
FIG. 2 is a rearward view, with portions cut away, of the control unit illustrated in FIG. l;
FIG. 3 is a plan view, with portions cut away, of the control unit illustrated in FIG. 2 as taken along line ; 3-3 of FIG 4;
; ~ ~FIG. 4 is a side view cross section of the control :~unit illustrated in FIG. 2, taken along line 4-4 of FIG. 2;
and FIG. 5 ;s a schematic diagram of a typical range control circuit in accordance with the present invention.
- -7'~
DETAILED DESCRIPTION OF THE PREFERRED EMBODI~ENTS
.
With reference to FIG. 1, there is illustrated in accordance with the present invention a freestanding domestic range 10 of the electrie type. The range ineludes a lower boxlike oven housing 12 typieally formed of sheet metal panels. The housing 12 ineludes a windowed oven door 12A and a eonventional utensil drawer 12B. The oven door 12A ean be opened to pivot downwardly about a lower horizontal axis to provide aecess to an oven ehamber 13, ineluding an oven heat-ing bake element 13A and one or more broiling elements (not shown). The element 13A and the non-illustrated broil ele-ments are formed of shielded resistance wire that heats to a high degree when a predetermined amount of eurrent flows through it. The oven chamber 13 can thus be highly heated by the heating ele~ents contained therein so as to cause pyro-lytie eleaning action of the oven walls, the oven door 12A
being loeked in a closed position during sueh pyrolytic cleaning, as is well known in the art.
A horizontal eooking platform 1~ eomprises the top of the boxlike oven housing 12, the horizontal eooking plat-form 14 including a plurality (e.g., four) of resistance wire surface heating elements 15 eonstituting burner locations upon which eooking utensils are placed for heating. The sur-face heating elements 15 are of a conventional nature and take the form of a pancake-shaped element of shielded resis-tance wire spirally wound as illustrated.
E~tending across the baek and upwardly from the horizontal cooking platform 14 is a control unit 16. The eontrol unit 16 is boxlike and ineludes a front panel 20 pro-viding, for example, six apertures through wh-ich extend the control shafts carrying four~burner control knobs 22, 23 and two oven control knobs 25. The eontrol panel 20 is typically 1~7~6~
formed of opaque glass and carries numerous indicia associ-ated with the manual control knobs 22, 23, 25 to permit the user to regulate the temperature of the surface heating ele-ments 15 and the temperature of the oven chamber 13. Located generally at the center or intermediate portion of the glass front panel 20 is a transparent window area 24 through which a time display mounted rearwardly of the panel 20 within the control unit 16 can be observed. To either side and below the display 24 is a plurality of touch pads 26 of the well-known capacitive switch type carried on the surface of the glass panel 20. The touch pads 26 are used to program an electronic control module to be subsequently illustrated and discussedl the module providing for the computerized time control of the oven chamber 13, the window area 2~ being used to visually feed back to the user programmed information inputted via the touch pads 26, as well as conventional time of day information. While the control unit 16 illustrated in FIG. 1 only provides for computerized turning on and turning off of the oven chamber 13 (with temperature control of the oven chamber 13 being conventionally provided via the oven control knobs 25), it is to be recognized that a nonapertured glass panel 20, including touch pads or equivalents in place of the knobs 22, 23, 25, could be provided so as to provide full electronic touch control for the surface heating elements 15 and all oven heating elements.
If one or more of the surface heating elements 15 are energized to a high power condition, without a cooking utensil in place on the respective elements, heat radiated by the elements will impinge on the control unit 16 and, in par-ticular, on the generally opaque glass front panel 20. Such a condition could cause the control unit 16 to be highly heated, wherein components within the control unit 16 would also be heated to a high extent. Further, pyrolytic cleaning of the oven chamber 13 at a temperature range of about i 17~f~7~
950F for a time period of, for example, two or more hours could cause the entire oven housing 12 to heat up as well as the control unit 16, thereby exposing the components within the control unit 16 to a high temperature condition. The temperature problem noted above becomes particularly acute i~
the range 10 is located in a confined area wherein only a limited amount of cooling air can be circulated by convection through and about the domestic range 10.
With re~erence to FIG. 2, there is illustrated a rearward view of the control unit 16 with the burner control knobs 22, 23 (and associated electric power control elements 22a, 22b, 23a, 23b) being illustrated in phantom along with the oven control knobs 25 (and associated electric power con-trol elements 25a, 25b). The rear of the control unit 16 is normally closed by a back panel or cover 17. In FIG. 2, a central portion of the back panel of the cover 17 has been cut away to reveal an electronic control module 30 which includes a power supply circuit board 30c (and other module boards to be subsequently illustrated) mounted on one side of a heat sink 40 in the form of a platelike metal bracket 42 having first and second side ~langes 44 r 46 fastened to an interior frame portion (to be subsequently illustrated) of the control unit 16. The control module 30 includes a plur-ality of temperature-sensitive, integrated circuit packages (e.g., a microprocessor, read-only-memory, etc.) of a known type which allow a range user to enter programmed material via the touch pad 26 (see FIG. 1) so as to determine when the oven chamber 13 (FIG. 1) will be heated on a time cycle basis.
To protect the module 30 from a damaging over-temperature condition, a temperature-sensitive switch means is located generally at the site of the control module. The switch means disables at least a portion of the range heating means (comprised of the oven heating element and surface heating element) at a predetermined sensed temperature to ~ 1~26~l7 preclude damage to the module 30 caused by high temeperature generated by the heating means of the range 10 (FIG. 1).
In a preferred form, the te~perature-sensitive switch means is comprised of a pair of normally closed, bimetal snap disc thermostatic switches 47, 48 of a known type manufactured by Therm-O-Disc Incorporated of Mansfield, Ohio. The type of bimetal snap disc switch illustrated in FIG. 2 is of the general type shown in U.S. patent 2,954,447. However, the switch illustrated in the '447 pat-ent is slightly more complex than the switches 47, 48 uti-lized in the preferred embodiment o~ the present invention.
rrhe bimetal snap disc switches 47, ~3 have an open end expos-ing their respective snap discs. The open ends of the switches 47, 48 are fastened to and closed by a portion of the heat sink flanges 44, 46, wherein heating of the flanges of the heat sink 42 in turn causes generally radiant heating o~ the birnetal snap disc located within the switches 47, 48.
Each switch 47, 48 is in series with a portion of the heating means of the range (surface and oven heating elements), wherein one or both of the switches 47, 48 can switch to an open condition to disable heating of the associated heating elements so as to maintain or lower the temperature of the module 30 to preclude its being damaged. The thermostatic switches 47, 48 will automatically reset to their normally closed electrically conducting condition to enable the dis-abled heating means portion upon a decrease ~rom a predeter-rnined temperature.
With reference to FIG. 3, the control module 30 is further illustrated as including a logic control circuit board 30a and a digital-type timer display circuit board 30b in addition to the power supply circuit board 30c. The inte-grated circuit containing boards 30a, 30b, 30c constitute the electronic control module 30, the boards 30a, 30b, 30c being fastened in position on the heat sink ~0 (FIG. ~) ' 17267~
having its flange portion 44, 46 fastened to an internal frame member 41 of the control unit 16. A display face 31 of the timer board 30b can be observed by the user through the transparent window area 24 (see FIG. 1) of the glass front panel 20, the timer display face 31 being spaced slightly inwardly away from the inner surface of the glass panel 20 to preclude conduction heating of the display face 31 by the panel 20.
The bimetal snap disc switches 47,48 are more clear-ly illustrated in FIG. 3 as having open-ended nose portions 49 in contiguous relationship against the heat sink flanges 44, 46, the portions 49 of the switches containing the bi-metallic discs which are directly exposed to radiant heating by the flanges 44, 46. In a preferred manner, the switches 47, 48 straddle the module 30 so as to fully protect it from a high temperature condition generated at either end of the control unit 16 (see FIG. 1). Furthèr, the use of an open-nose switch permits a very fast switch response time to a sensed over-temperature condition.
With reference to FIG. 4, the bimetallic snap disc switch ~7 (which is identical to the snap disc switch 48) is further illustrated as including, in addition to the nose portion 49, a mounting bracket 49b which secures, by appro-priate screws 49c, the switch 47 in position against the heat sink flange 44. A pair of contacts 49a (only one shown) has connected between them a single pole switch which is in a normally closed position until a high temperature condition is reached wherein a bimetallic snap disc in the nose portion 49 actuates the switch to an open condition in a well known manner.
Turning to FIG. 5, there is illustrated in schematic fashion a typical control circuit for a domestic range of the type illustrated in FIGS. 1 through 4. The electr;c power control elements 22a, 22b, 23a, 23b for the s~rface heating ll~72~
elements 15 are schematically illustrated as being energized by a pair of power lines Ll, L2 in a typical fashion.
Power to the elements 15 energi~ed via control elements 22a, 22b, and 23a is provided via the snap disc switch 48. The snap disc switch 47 provides power to control element 23b as well as to the oven control circui~ry 60 via a power control line 65. The oven control circuitry ~0 is oE a conventional nature and energizes, in a known fashion, the oven heating elements 13a along with, for example, a broil element 63 and its associated speed broil element 61. It can be seen that opening of the thermostatic switches 47, 48 will disable the powering of the respective portions of the heating elements controlled so as to preclude overheating of the control module 30 as discussed above.
While the present invention has been illustrated in the environment of a domestic range of the electric resis-tance heating type, it is to be understood that the invention has equal applicability to a gas range wherein over-temperature protection of an electronic control module of the type illustrated is desired. Also as noted earlier, the present invention applies to a fully electronically con-trolled range, although FIGS. 1 through 4 illustrate the range having conventional knob-type mechanical controls for the heating elements, both of the surface heating type and the oven heating type.
The switches 47, 48 in conjunction with the heat sink 40 advantageously preclude overheating of the associated control module 30. The switches 47, 48 are relatively low in cost and easily handle high current loads over many switch cycles. The relative simplicity of the heat sink in combina-tion with the switches 47, 48 provides a very rugged and reliable over-temperature protection means for the electronic control module 30.
fi ~ ~
Although the preferred embodiment of this invention has been shown and described, it should be understood that various modifications and rearran~ements of the parts may be resorted to without departing from the scope of the invention as disclosed and claimed herein.
` ~ 17~67~f A fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a domestic range of the electric type incorporating the present invention, the range including an electronic module containing control unit extending upwardly from and across the back of the top hori-zontal cooking platform of the range;
FIG. 2 is a rearward view, with portions cut away, of the control unit illustrated in FIG. l;
FIG. 3 is a plan view, with portions cut away, of the control unit illustrated in FIG. 2 as taken along line ; 3-3 of FIG 4;
; ~ ~FIG. 4 is a side view cross section of the control :~unit illustrated in FIG. 2, taken along line 4-4 of FIG. 2;
and FIG. 5 ;s a schematic diagram of a typical range control circuit in accordance with the present invention.
- -7'~
DETAILED DESCRIPTION OF THE PREFERRED EMBODI~ENTS
.
With reference to FIG. 1, there is illustrated in accordance with the present invention a freestanding domestic range 10 of the electrie type. The range ineludes a lower boxlike oven housing 12 typieally formed of sheet metal panels. The housing 12 ineludes a windowed oven door 12A and a eonventional utensil drawer 12B. The oven door 12A ean be opened to pivot downwardly about a lower horizontal axis to provide aecess to an oven ehamber 13, ineluding an oven heat-ing bake element 13A and one or more broiling elements (not shown). The element 13A and the non-illustrated broil ele-ments are formed of shielded resistance wire that heats to a high degree when a predetermined amount of eurrent flows through it. The oven chamber 13 can thus be highly heated by the heating ele~ents contained therein so as to cause pyro-lytie eleaning action of the oven walls, the oven door 12A
being loeked in a closed position during sueh pyrolytic cleaning, as is well known in the art.
A horizontal eooking platform 1~ eomprises the top of the boxlike oven housing 12, the horizontal eooking plat-form 14 including a plurality (e.g., four) of resistance wire surface heating elements 15 eonstituting burner locations upon which eooking utensils are placed for heating. The sur-face heating elements 15 are of a conventional nature and take the form of a pancake-shaped element of shielded resis-tance wire spirally wound as illustrated.
E~tending across the baek and upwardly from the horizontal cooking platform 14 is a control unit 16. The eontrol unit 16 is boxlike and ineludes a front panel 20 pro-viding, for example, six apertures through wh-ich extend the control shafts carrying four~burner control knobs 22, 23 and two oven control knobs 25. The eontrol panel 20 is typically 1~7~6~
formed of opaque glass and carries numerous indicia associ-ated with the manual control knobs 22, 23, 25 to permit the user to regulate the temperature of the surface heating ele-ments 15 and the temperature of the oven chamber 13. Located generally at the center or intermediate portion of the glass front panel 20 is a transparent window area 24 through which a time display mounted rearwardly of the panel 20 within the control unit 16 can be observed. To either side and below the display 24 is a plurality of touch pads 26 of the well-known capacitive switch type carried on the surface of the glass panel 20. The touch pads 26 are used to program an electronic control module to be subsequently illustrated and discussedl the module providing for the computerized time control of the oven chamber 13, the window area 2~ being used to visually feed back to the user programmed information inputted via the touch pads 26, as well as conventional time of day information. While the control unit 16 illustrated in FIG. 1 only provides for computerized turning on and turning off of the oven chamber 13 (with temperature control of the oven chamber 13 being conventionally provided via the oven control knobs 25), it is to be recognized that a nonapertured glass panel 20, including touch pads or equivalents in place of the knobs 22, 23, 25, could be provided so as to provide full electronic touch control for the surface heating elements 15 and all oven heating elements.
If one or more of the surface heating elements 15 are energized to a high power condition, without a cooking utensil in place on the respective elements, heat radiated by the elements will impinge on the control unit 16 and, in par-ticular, on the generally opaque glass front panel 20. Such a condition could cause the control unit 16 to be highly heated, wherein components within the control unit 16 would also be heated to a high extent. Further, pyrolytic cleaning of the oven chamber 13 at a temperature range of about i 17~f~7~
950F for a time period of, for example, two or more hours could cause the entire oven housing 12 to heat up as well as the control unit 16, thereby exposing the components within the control unit 16 to a high temperature condition. The temperature problem noted above becomes particularly acute i~
the range 10 is located in a confined area wherein only a limited amount of cooling air can be circulated by convection through and about the domestic range 10.
With re~erence to FIG. 2, there is illustrated a rearward view of the control unit 16 with the burner control knobs 22, 23 (and associated electric power control elements 22a, 22b, 23a, 23b) being illustrated in phantom along with the oven control knobs 25 (and associated electric power con-trol elements 25a, 25b). The rear of the control unit 16 is normally closed by a back panel or cover 17. In FIG. 2, a central portion of the back panel of the cover 17 has been cut away to reveal an electronic control module 30 which includes a power supply circuit board 30c (and other module boards to be subsequently illustrated) mounted on one side of a heat sink 40 in the form of a platelike metal bracket 42 having first and second side ~langes 44 r 46 fastened to an interior frame portion (to be subsequently illustrated) of the control unit 16. The control module 30 includes a plur-ality of temperature-sensitive, integrated circuit packages (e.g., a microprocessor, read-only-memory, etc.) of a known type which allow a range user to enter programmed material via the touch pad 26 (see FIG. 1) so as to determine when the oven chamber 13 (FIG. 1) will be heated on a time cycle basis.
To protect the module 30 from a damaging over-temperature condition, a temperature-sensitive switch means is located generally at the site of the control module. The switch means disables at least a portion of the range heating means (comprised of the oven heating element and surface heating element) at a predetermined sensed temperature to ~ 1~26~l7 preclude damage to the module 30 caused by high temeperature generated by the heating means of the range 10 (FIG. 1).
In a preferred form, the te~perature-sensitive switch means is comprised of a pair of normally closed, bimetal snap disc thermostatic switches 47, 48 of a known type manufactured by Therm-O-Disc Incorporated of Mansfield, Ohio. The type of bimetal snap disc switch illustrated in FIG. 2 is of the general type shown in U.S. patent 2,954,447. However, the switch illustrated in the '447 pat-ent is slightly more complex than the switches 47, 48 uti-lized in the preferred embodiment o~ the present invention.
rrhe bimetal snap disc switches 47, ~3 have an open end expos-ing their respective snap discs. The open ends of the switches 47, 48 are fastened to and closed by a portion of the heat sink flanges 44, 46, wherein heating of the flanges of the heat sink 42 in turn causes generally radiant heating o~ the birnetal snap disc located within the switches 47, 48.
Each switch 47, 48 is in series with a portion of the heating means of the range (surface and oven heating elements), wherein one or both of the switches 47, 48 can switch to an open condition to disable heating of the associated heating elements so as to maintain or lower the temperature of the module 30 to preclude its being damaged. The thermostatic switches 47, 48 will automatically reset to their normally closed electrically conducting condition to enable the dis-abled heating means portion upon a decrease ~rom a predeter-rnined temperature.
With reference to FIG. 3, the control module 30 is further illustrated as including a logic control circuit board 30a and a digital-type timer display circuit board 30b in addition to the power supply circuit board 30c. The inte-grated circuit containing boards 30a, 30b, 30c constitute the electronic control module 30, the boards 30a, 30b, 30c being fastened in position on the heat sink ~0 (FIG. ~) ' 17267~
having its flange portion 44, 46 fastened to an internal frame member 41 of the control unit 16. A display face 31 of the timer board 30b can be observed by the user through the transparent window area 24 (see FIG. 1) of the glass front panel 20, the timer display face 31 being spaced slightly inwardly away from the inner surface of the glass panel 20 to preclude conduction heating of the display face 31 by the panel 20.
The bimetal snap disc switches 47,48 are more clear-ly illustrated in FIG. 3 as having open-ended nose portions 49 in contiguous relationship against the heat sink flanges 44, 46, the portions 49 of the switches containing the bi-metallic discs which are directly exposed to radiant heating by the flanges 44, 46. In a preferred manner, the switches 47, 48 straddle the module 30 so as to fully protect it from a high temperature condition generated at either end of the control unit 16 (see FIG. 1). Furthèr, the use of an open-nose switch permits a very fast switch response time to a sensed over-temperature condition.
With reference to FIG. 4, the bimetallic snap disc switch ~7 (which is identical to the snap disc switch 48) is further illustrated as including, in addition to the nose portion 49, a mounting bracket 49b which secures, by appro-priate screws 49c, the switch 47 in position against the heat sink flange 44. A pair of contacts 49a (only one shown) has connected between them a single pole switch which is in a normally closed position until a high temperature condition is reached wherein a bimetallic snap disc in the nose portion 49 actuates the switch to an open condition in a well known manner.
Turning to FIG. 5, there is illustrated in schematic fashion a typical control circuit for a domestic range of the type illustrated in FIGS. 1 through 4. The electr;c power control elements 22a, 22b, 23a, 23b for the s~rface heating ll~72~
elements 15 are schematically illustrated as being energized by a pair of power lines Ll, L2 in a typical fashion.
Power to the elements 15 energi~ed via control elements 22a, 22b, and 23a is provided via the snap disc switch 48. The snap disc switch 47 provides power to control element 23b as well as to the oven control circui~ry 60 via a power control line 65. The oven control circuitry ~0 is oE a conventional nature and energizes, in a known fashion, the oven heating elements 13a along with, for example, a broil element 63 and its associated speed broil element 61. It can be seen that opening of the thermostatic switches 47, 48 will disable the powering of the respective portions of the heating elements controlled so as to preclude overheating of the control module 30 as discussed above.
While the present invention has been illustrated in the environment of a domestic range of the electric resis-tance heating type, it is to be understood that the invention has equal applicability to a gas range wherein over-temperature protection of an electronic control module of the type illustrated is desired. Also as noted earlier, the present invention applies to a fully electronically con-trolled range, although FIGS. 1 through 4 illustrate the range having conventional knob-type mechanical controls for the heating elements, both of the surface heating type and the oven heating type.
The switches 47, 48 in conjunction with the heat sink 40 advantageously preclude overheating of the associated control module 30. The switches 47, 48 are relatively low in cost and easily handle high current loads over many switch cycles. The relative simplicity of the heat sink in combina-tion with the switches 47, 48 provides a very rugged and reliable over-temperature protection means for the electronic control module 30.
fi ~ ~
Although the preferred embodiment of this invention has been shown and described, it should be understood that various modifications and rearran~ements of the parts may be resorted to without departing from the scope of the invention as disclosed and claimed herein.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a domestic range having a radiant-type heating means temperature-regulated by a control unit including an electronic control module, an over-temperature protection means for the control module comprising:
a temperature-sensitive switch means located generally at the site of the control module, the switch means disabling at least a portion of the heating means at a predetermined sensed temperature to preclude damage to the module caused by high temperatures generated by the heating means; and a metallic heat sink member, both the switch means and the module being fixed thereto, the switch means sensing the temperature of the heat sink member portion to which it is fixed.
a temperature-sensitive switch means located generally at the site of the control module, the switch means disabling at least a portion of the heating means at a predetermined sensed temperature to preclude damage to the module caused by high temperatures generated by the heating means; and a metallic heat sink member, both the switch means and the module being fixed thereto, the switch means sensing the temperature of the heat sink member portion to which it is fixed.
2. In a domestic range of the electric type-having a plurality of resistance wire heating elements of the radiant-type that are temperature-regulated by a control unit including an electronic control module, an over-temperature protection means for the control module comprising:
a normally closed temperature-sensitive electrical switch means connected in electrical series relationship between at least one of the heating elements and its electrical power source, the switch means being located generally at the site of the control module to terminate the application of electrical power to the heating element at a predetermined sensed temperature wherein heating of the module by the heating elements is limited, the switch means includes a pair of bimetallic snap disc switches, one switch being in electrical series relationship with a portion of the heating elements, the other switch being in electrical series relationship with the remaining portion of the heating elements, the switches each being located at an opposed side of the module in adjacent spaced relationship thereto, the module being straddled by the switches, the switches and the module being fixed to a common heat sink member, the switches sensing the temperature of the heat sink member portions to which they are fixed.
a normally closed temperature-sensitive electrical switch means connected in electrical series relationship between at least one of the heating elements and its electrical power source, the switch means being located generally at the site of the control module to terminate the application of electrical power to the heating element at a predetermined sensed temperature wherein heating of the module by the heating elements is limited, the switch means includes a pair of bimetallic snap disc switches, one switch being in electrical series relationship with a portion of the heating elements, the other switch being in electrical series relationship with the remaining portion of the heating elements, the switches each being located at an opposed side of the module in adjacent spaced relationship thereto, the module being straddled by the switches, the switches and the module being fixed to a common heat sink member, the switches sensing the temperature of the heat sink member portions to which they are fixed.
3. An apparatus according to claim 2, wherein the heat sink is enclosed inside the control unit, the control unit being boxlike and having a front exterior glass panel exposed to radiant heat from one or more of the radiant type heating elements, the heat sink being spaced from the front panel, the front panel being generally opaque through a major portion of its extent.
4. In a freestanding domestic range of the electric type having a horizontal cooking platform providing a plurality of pancake-shaped surface heating elements of the radiant-type formed of spirally wound resistance wire, an elongated boxlike control unit extending upwardly from and across the back edge of the cooking platform, the control unit regulating the temperature of the surface heating elements, an oven chamber of the pyrolytic self-cleaning type being located below the cooking platform and including radiant type heating elements formed of resistance wire also temperature-regulated by the control unit, an over-temperature protection means for protecting an electronic module located inside of the boxlike control unit, comprising:
a heat sink constituted by a metal platelike member enclosed by the control unit and spaced from the exterior walls of the control unit, the electronic module being fixed to and generally centered on the heat sink; and a pair of bimetallic snap disc-actuated electrical switches fixed to the heat sink member, the switches straddling the module and being spaced from it, the switches being equidistantly spaced above the horizontal cooking platform, the switches being normally closed at and below a predetermined sensed temperature, one switch being in electrical series relationship with a portion of the heating elements, the other switch being in electrical series relationship with a remaining portion of the heating elements, the switches independently cycling their respective heating element portions on and off to maintain the control module below a predetermined temperature caused primarily by heat generated by the heating elements.
a heat sink constituted by a metal platelike member enclosed by the control unit and spaced from the exterior walls of the control unit, the electronic module being fixed to and generally centered on the heat sink; and a pair of bimetallic snap disc-actuated electrical switches fixed to the heat sink member, the switches straddling the module and being spaced from it, the switches being equidistantly spaced above the horizontal cooking platform, the switches being normally closed at and below a predetermined sensed temperature, one switch being in electrical series relationship with a portion of the heating elements, the other switch being in electrical series relationship with a remaining portion of the heating elements, the switches independently cycling their respective heating element portions on and off to maintain the control module below a predetermined temperature caused primarily by heat generated by the heating elements.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/312,097 US4431907A (en) | 1981-10-16 | 1981-10-16 | Range temperature protection |
| US312,097 | 1981-10-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1172677A true CA1172677A (en) | 1984-08-14 |
Family
ID=23209868
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000408931A Expired CA1172677A (en) | 1981-10-16 | 1982-08-06 | Range temperature protection |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US4431907A (en) |
| AU (1) | AU553325B2 (en) |
| CA (1) | CA1172677A (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4527049A (en) * | 1984-02-09 | 1985-07-02 | Raytheon Company | Microprocessor controlled electric range |
| SE8402344L (en) * | 1984-04-30 | 1985-12-08 | Arnold Ingemar Magnusson | Overheating ALARM |
| US4526332A (en) * | 1984-06-18 | 1985-07-02 | The Maytag Company | Control panel clock lens arrangement |
| DE3528229A1 (en) * | 1985-08-06 | 1987-02-12 | Bosch Siemens Hausgeraete | ARRANGEMENT FOR CONTROLLING ELECTRICAL CONSUMERS IN OVENS |
| US4634843A (en) * | 1986-01-16 | 1987-01-06 | General Electric Company | Dual mode power control arrangement for cooking appliance |
| US4659909A (en) * | 1986-01-23 | 1987-04-21 | Knutson Arthur E | Kitchen range safety shutoff |
| DE3635324A1 (en) * | 1986-10-17 | 1988-04-28 | Diehl Gmbh & Co | ARRANGEMENT FOR CONTROLLING THE POWER OF OHMSER CONSUMERS |
| US4896004A (en) * | 1987-10-09 | 1990-01-23 | White Consolidated Industries, Inc. | Low-profile range control switch |
| NZ275488A (en) * | 1993-10-21 | 1996-11-26 | Otter Controls Ltd | Water boiling kettle with planar heating element |
| FR2719890B3 (en) * | 1994-05-10 | 1996-08-09 | Wyn Thomas Peris | Cooking oven. |
| US5726424A (en) * | 1996-05-13 | 1998-03-10 | Technology Licensing Corporation | Modular control enclosure for a cooking appliance |
| US5889259A (en) * | 1997-05-22 | 1999-03-30 | Hp Intellectual Corp. | Toaster oven control assembly |
| ES2215423B1 (en) * | 2000-12-19 | 2006-02-01 | Bsh Electrodomesticos España, S.A. | KITCHEN WITH OVEN. |
| US7420142B2 (en) * | 2002-07-26 | 2008-09-02 | Illinois Tool Works, Inc | Power control module for electrical appliances |
| US6951997B2 (en) * | 2002-07-26 | 2005-10-04 | Ark-Les Corporation | Control of a cooktop heating element |
| US20050284460A1 (en) * | 2004-06-28 | 2005-12-29 | The Stanley Works | Oven door latch lock |
| KR101580175B1 (en) * | 2008-11-14 | 2016-01-05 | 삼성전자 주식회사 | Circuit printed circuit board assembly of electronic appliance |
| EP2930435B1 (en) * | 2014-04-08 | 2017-09-27 | Whirlpool EMEA S.p.A | Household cooking appliance |
| US10085584B2 (en) | 2014-06-09 | 2018-10-02 | Whirlpool Corporation | Method of regulating temperature for sous vide cooking and apparatus therefor |
| US11847010B2 (en) * | 2018-07-02 | 2023-12-19 | Haier Us Appliance Solutions, Inc. | Appliance and methods for operating same in a safety-critical operation |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2399423A (en) * | 1941-08-14 | 1946-04-30 | Westinghouse Electric Corp | Heating apparatus |
| US2392635A (en) * | 1942-06-17 | 1946-01-08 | Westinghouse Electric Corp | Heating apparatus |
| US2409414A (en) * | 1942-07-08 | 1946-10-15 | Westinghouse Electric Corp | Heating apparatus |
| US2866881A (en) * | 1955-12-19 | 1958-12-30 | Kearfott Company Inc | Temperature controlled electrically heated window and window wiper system |
| US2861151A (en) * | 1957-04-22 | 1958-11-18 | Westinghouse Electric Corp | Temperature-controlled apparatus |
| US3612826A (en) * | 1970-07-17 | 1971-10-12 | Gen Motors Corp | Surface temperature indicator light for ceramic top infrared radiant range |
| US3899656A (en) * | 1974-12-13 | 1975-08-12 | Gen Motors Corp | Self-cleaning oven with temperature limiting protection system for bake and clean |
| US3912904A (en) * | 1974-12-24 | 1975-10-14 | White Westinghouse Corp | Self-cleaning oven latch-lock-control arrangement |
-
1981
- 1981-10-16 US US06/312,097 patent/US4431907A/en not_active Expired - Lifetime
-
1982
- 1982-08-06 CA CA000408931A patent/CA1172677A/en not_active Expired
- 1982-09-27 AU AU88750/82A patent/AU553325B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| US4431907A (en) | 1984-02-14 |
| AU553325B2 (en) | 1986-07-10 |
| AU8875082A (en) | 1983-04-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |