Title:
FAN APPARENCY ARRANGEMENT FOR AN APPLIANCE
Kind Code:
A1


Abstract:
A fan apparency arrangement for an appliance having a cooling fan for moving cooling air through an airflow pathway is disclosed. The arrangement includes a bracket mounted to the appliance's interior frame and one or more thermal switches mounted to the bracket. The thermal switches have an activation temperature at which they signal a malfunction of the fan when the fan fails to move sufficient cooling air through the airflow pathway. The bracket is configured to secure the switches within the airflow pathway to maintain the switches at a temperature below their respective activation temperatures when the fan is operating properly. Additionally, the bracket conducts heat directly from the frame to the switches so that when the fan malfunctions, the reaction time of the switches in reaching their respective activation temperatures is reduced. An appliance incorporating such a fan apparency arrangement is also disclosed.



Inventors:
Zehr, Edwin Glenn (Sugar Valley, GA, US)
Application Number:
13/479854
Publication Date:
11/28/2013
Filing Date:
05/24/2012
Assignee:
ZEHR EDWIN GLENN
Primary Class:
Other Classes:
454/256
International Classes:
F24F7/007; F24C15/00
View Patent Images:



Primary Examiner:
LAU, JASON
Attorney, Agent or Firm:
Dority & Manning, P.A. and Haier US Appliance (Greenville, SC, US)
Claims:
What is claimed is:

1. A fan apparency arrangement for an appliance comprising an interior frame and a fan for moving cooling air through an airflow pathway in an interior of the appliance, the arrangement comprising: a bracket mounted to a section of the frame in such a manner that at least a portion of the bracket directly contacts the frame; and at least one thermal switch mounted to the bracket and comprising an activation temperature at which the at least one thermal switch signals malfunction of the fan, wherein the bracket (i) secures the at least one thermal switch at a location within the airflow pathway, so that the cooling air flows substantially around the at least one thermal switch to maintain the at least one thermal switch at a temperature below the activation temperature and (ii) conducts heat directly from the frame to the at least one thermal switch so that when the fan fails to move sufficient cooling air through the airflow pathway, the activation temperature of the at least one thermal switch is reached.

2. The fan apparency arrangement of claim 1, wherein an interface between the at least one thermal switch and the bracket is approximately centered relative to an adjacent section of the airflow pathway.

3. The fan apparency arrangement of claim 1, wherein the bracket comprises at least one mounting surface onto which the at least one thermal switch is mounted, and at least two leg members extending from the at least one mounting surface.

4. The fan apparency arrangement of claim 3, wherein when the bracket is mounted to the frame, the at least two leg members space the at least one mounting surface away from the frame so that cooling air is allowed to flow between the at least one mounting surface and the frame to prevent obstruction of the airflow pathway and allow cooling air to flow underneath the at least one thermal switch.

5. The fan apparency arrangement of claim 3, wherein at least one of the at least two leg members includes a mounting appendage for securing the bracket to the frame, the mounting appendage directly contacting the frame.

6. The fan apparency arrangement of claim 1, wherein the at least one thermal switch comprises a first thermal switch comprising a first activation temperature and a second thermal switch comprising a second activation temperature higher than the first activation temperature.

7. The fan apparency arrangement of claim 6, wherein the bracket conducts heat substantially evenly from the frame to both the first thermal switch and the second thermal switch.

8. The fan apparency arrangement of claim 6, wherein the first thermal switch is configured to signal malfunction of the fan during an operative cycle of a first heating operation, but remains in a nonfunctioning state during an operative cycle of a second heating operation; and the second thermal switch is configured to signal malfunction of the fan during the operative cycle of the second heating operation, but remains in a nonfunctioning state during the operative cycle of the first heating operation.

9. The fan apparency arrangement of claim 8, wherein the appliance is a cooking appliance, the first heating operation is a baking or cooking operation and the second heating operation is a self-cleaning operation.

10. The fan apparency arrangement of claim 1, wherein the bracket is made from aluminum, steel or aluminized steel.

11. An appliance comprising: a frame; an airflow pathway; a fan operative to move cooling air through the airflow pathway; a bracket mounted to a section of the frame in such a manner that at least a portion of the bracket directly contacts the frame; and at least one thermal switch mounted to the bracket and comprising an activation temperature at which the at least one thermal switch signals malfunction of the fan, wherein the bracket (i) secures the at least one thermal switch at a location within the airflow pathway, so that the cooling air flows substantially around the at least one thermal switch to maintain the at least one thermal switch at a temperature below the activation temperature when the fan is operating properly, and (ii) conducts heat directly from the frame to the at least one thermal switch so that when the fan fails to move sufficient cooling air through the airflow pathway, the at least one thermal switch reaches the activation temperature.

12. The fan apparency arrangement of claim 11, wherein an interface between the at least one thermal switch and the bracket is approximately centered relative to an adjacent section of the airflow pathway.

13. The fan apparency arrangement of claim 11, wherein the bracket comprises at least one mounting surface onto which the at least one thermal switch is mounted, and at least two leg members extending from the at least one mounting surface.

14. The fan apparency arrangement of claim 13, wherein when the bracket is mounted to the frame, the at least two leg members space the at least one mounting surface away from the frame so that cooling air is allowed to flow between the at least one mounting surface and the frame to prevent obstruction of the airflow pathway and allow cooling air to flow underneath the at least one thermal switch.

15. The fan apparency arrangement of claim 13, wherein at least one of the at least two leg members includes a mounting appendage for securing the bracket to the frame, the mounting appendage directly contacting the frame.

16. The fan apparency arrangement of claim 11, wherein the at least one thermal switch comprises a first thermal switch comprising a first activation temperature and a second thermal switch comprising a second activation temperature higher than the first activation temperature.

17. The fan apparency arrangement of claim 16, wherein the bracket conducts heat substantially evenly from the frame to both the first thermal switch and the second thermal switch.

18. The fan apparency arrangement of claim 16, wherein the first thermal switch is configured to signal malfunction of the fan during an operative cycle of a first heating operation, but remains in a nonfunctioning state during an operative cycle of a second heating operation; and the second thermal switch is configured to signal malfunction of the fan during the operative cycle of the second heating operation, but remains in a nonfunctioning state during the operative cycle of the first heating operation.

19. The fan apparency arrangement of claim 18, wherein the appliance is a cooking appliance, the first appliance operation is a baking or cooking operation and the second appliance operation is a self-cleaning operation.

Description:

BACKGROUND OF THE INVENTION

The present invention relates generally to a fan apparency arrangement. More particularly, the present invention relates to a fan apparency arrangement for an appliance and an appliance incorporating such a fan apparency arrangement.

Appliances such as cooking ranges and wall ovens are widely used. A cooking range typically includes an oven with a front-opening access door, and at least one heating element for heating up the inside of the oven cavity. Wall ovens have a similar configuration. As is known in the art, when energized, the heating element can heat up the inside of the oven cavity to a relatively high temperature. Also as is known in the art, such cooking appliances often have a fan which is used to draw cooling air into the interior of the appliance and circulate the cooling air in one or more airflow channels to cool a structural component of the appliance, such as a front-opening access door, or a heat sensitive component such as an electronic control. If an appliance employs a fan for cooling, some certification institutions, such as Underwriters Laboratories Inc. (UL), require that a fan apparency device (FAD) be employed to determine or detect whether the fan is working properly.

As is known in the art, for appliances that employ a fan to provide cooling airflow, when a user selects or chooses a heating operation of the appliance and turns on the appliance, the act of turning on the appliance also turns on the fan to ensure proper cooling. The FAD then determines or detects whether the fan is working properly while the heating operation is in progress. If the fan is working properly, the FAD enables the selected heating operation of the appliance to proceed. On the other hand, if the fan is not working properly, the FAD prevents the selected heating operation of the appliance from proceeding.

Various types of FADs are used to determine or detect whether the fan is working properly. The most widely used FADs are thermal switches and sail switches. A thermal switch typically employs a heat sensitive bimetal member having a predetermined set point or switch activation temperature. Should the fan stop or fail to move sufficient cooling air where intended during a heating operation, such as a cooking operation, the bimetal member will absorb heat generated by the heating element until the activation temperature is reached, at which time the thermal switch signals a fan malfunction. Sail switches, on the other hand, rely on the movement of a mechanical lever to activate the switch. The movement is driven by a positive or negative pressure applied to a sail member attached to the lever, which is generated by the circulating cooling air. When the fan moves sufficient cooling air, the lever is maintained in a first position and the switch is idle. However, when the fan fails to move sufficient cooling air, the lever will move to a second position, which mechanically activates the switch and signals a fan malfunction. Thermal switches generally offer greater flexibility in terms of placement options (including location and orientation) about the interior of an appliance in comparison to sail switches, which must be placed and orientated with precision to ensure proper operation. However, thermal switches usually have a relatively slow reaction time in comparison to sail switches because there is an inherent delay or lag resulting from the time it takes to transfer enough heat from the heating element to the thermal switch to cause the thermal switch to reach its activation temperature.

Therefore, it would be desirable to provide a fan apparency arrangement that uses one or more thermal switches, but has a faster overall reaction time.

BRIEF DESCRIPTION OF THE INVENTION

As described herein, the preferred embodiments of the present invention overcome one or more of the above or other disadvantages known in the art.

One aspect of the present invention relates to a fan apparency arrangement for an appliance comprising an interior frame and a fan for moving cooling air through an airflow pathway in an interior of the appliance. The fan apparency arrangement includes a bracket mounted to a section of the interior frame in such a manner that at least a portion of the bracket directly contacts the frame. The arrangement further includes at least one thermal switch mounted to the bracket. The at least one thermal switch has an activation temperature which will be exceeded when the fan fails to move sufficient cooling air through the airflow pathway causing the switch to signal a malfunction of the fan. The bracket is configured to secure the at least one thermal switch at a location within the airflow pathway, so that when the fan is operating properly, the cooling air flows substantially around the at least one thermal switch to maintain the at least one thermal switch at a temperature below the activation temperature. Additionally, the bracket conducts heat directly from the frame, which absorbs heat generated by the appliance's heating element during a cooking and/or cleaning operation, to the at least one thermal switch so that when the fan fails to move the cooling air through the airflow pathway, a reaction time of the at least one thermal switch in reaching the activation temperature is reduced relative to FADs using conventional thermal switch configurations.

Another aspect of the present invention relates to an appliance that includes a frame, an airflow pathway and a fan operative to move cooling air through the airflow pathway. The appliance further includes a bracket mounted to a section of the frame in such a manner that at least a portion of the bracket directly contacts the frame, and at least one thermal switch mounted to the bracket. The at least one thermal switch has an activation temperature which will be exceeded when the fan fails to move sufficient cooling air through the airflow pathway causing the switch to signal a malfunction of the fan. The bracket is configured to secure the at least one thermal switch at a location within the airflow pathway, so that the when the fan is operating properly, cooling air flows substantially around the at least one thermal switch to maintain the at least one thermal switch at a temperature below the activation temperature. Additionally, the bracket conducts heat directly from the frame to the at least one thermal switch so that when the fan fails to move the cooling air through the airflow pathway, a reaction time of the at least one thermal switch in reaching the activation temperature is reduced.

These and other aspects and advantages of the preferred embodiments of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. Moreover, the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary cooking range incorporating a fan apparency arrangement (not shown) in accordance with an embodiment of the present invention;

FIG. 2 is a schematic, cross-sectional view taken along line 2-2 in FIG. 1;

FIG. 3 is perspective view of the top portion of the cooking range of FIG. 1 with the cook top removed;

FIG. 4 is a magnified perspective view an embodiment of the fan apparency arrangement illustrated in FIG. 3;

FIG. 5 is a magnified perspective view of an alternative embodiment of the fan apparency arrangement illustrated in FIG. 4; and

FIG. 6 is a perspective view of an alternative embodiment of the bracket of the fan apparency arrangement illustrated in FIG. 4.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THE INVENTION

With reference to FIG. 1, an exemplary appliance incorporating a fan apparency arrangement in accordance with an embodiment of the present invention is generally designated by reference numeral 100. By way of a non-limiting example, the appliance 100 is shown as a slide-in double oven cooking range. However, the embodiments of the present invention can also be used in other types of appliances such as free standing cooking ranges, single oven cooking ranges, ovens, dryers, etc.

The cooking range 100 comprises an outer body or housing 110 and a generally rectangular shaped cook top 114. Two ovens, upper oven 115 and lower oven 116 (not shown in detail), are positioned below the cook top 114 and have respective front-opening access doors 117, 118 for closing the oven cavities. A control panel 120 extends outward from the front edge 121 of the cook top 114 and contains various controls 122 for selectively operating heating elements such as electric burners 124 on the cook top 114 and heating elements (not shown) in the ovens 115, 116. The controls 122 also operate specific heating operations, such baking, broiling and self-cleaning operations.

As shown in FIG. 2, the cooking range 100 further comprises an interior frame 119, which supports the ovens 115, 116 and provides a structure onto which the access doors 117, 118 are hingedly mounted. The frame 119 is typically formed from a heat conducting metal, such as steel, aluminum or any of numerous known heat conducting metals or metal alloys so long as the chosen material is capable of supporting the ovens and access doors. In the illustrated embodiment, the interior frame 119 comprises two frame sections—an upper frame section 119a and a lower frame section 119b—where the upper frame section 119a supports the upper oven 115 and the lower frame section 119b supports the lower oven 116. The frame sections 119a-b are in intimate contact such that they are thermally coupled in a manner that heat will readily transfer at least by conduction from one of the frame sections to the other of the frame sections and vice versa. Alternatively, the interior frame 119 can be formed as a single frame section that supports both ovens 115, 116. Due to the location of frame sections 119a-b relative to the ovens 115, 116, heat generated by the ovens' respective heating elements (not shown) will readily transfer from the heating elements to the oven walls (i.e. the walls of the ovens 115, 116) and then to the frame sections 119a-b, so that the frame sections 119a-b rapidly reach elevated temperatures substantially equal to or proportional to the actual internal oven temperatures.

On an interior of the housing 110 lies an airflow pathway 130 through which cooling air flows. In a typical embodiment, the airflow pathway 130 comprises one or more ducts or channels that run between the housing 110 and the ovens 115, 116 and in proximity to the control panel 120. The ducts or channels can be separate components inserted between the housing 110 and ovens 115, 116 and/or can be formed from one or more gaps located between the housing and ovens. The airflow pathway 130 can run along the interior of a rear wall 123 of the housing 110, as illustrated in FIG. 2, and/or can run along the interior of a side wall (not shown). The airflow pathway 130 is in fluid or flow communication with the ambient air on the outside of the appliance 100 via one or more air inlets 131, 132.

A fan 140 is positioned in the airflow pathway 130 in an interior of the cooking range 100. The fan 140 typically draws ambient or cooling air into the interior of the cooking range 100 and moves the cooling air through the airflow pathway 130 to, for example, cool off structural components of the cooking range 100 such as the front-opening access doors 117, 118, or heat sensitive components such as the control panel 120, an electronic control (not shown) or a thermal switch (described in further detail below). The term “fan” used herein covers fans, air blowers and other devices suitable for moving air. These devices are well known in the art, and therefore will not be discussed in further detail. When energized and working properly, the fan 140 generates airflow through the airflow pathway 130 as shown by the arrows 134. More specifically, when energized and working properly, the fan 140 draws ambient air from at least the air inlets 131, 132 and forces the ambient air to flow through the airflow pathway 130 and exit the pathway via an air outlet 136.

Referring now to FIGS. 3 and 4, an embodiment of a fan apparency arrangement 150 for an appliance such as the aforementioned cooking range 100 is illustrated. The fan apparency arrangement comprises a bracket 160 and a pair of thermal switches 180, 182 (i.e., a first thermal switch 180 and a second thermal switch 182) mounted to the bracket 160. Thermal switches are well known in the art, and thus the details of their inner workings will not be discussed here. Although two thermal switches are shown in the illustrated embodiment, alternative embodiments comprising one or more thermal switches (i.e., at least one thermal switch), are intended to be covered by the present disclosure (see, for example, the single switch embodiment illustrated in FIG. 5). Typically, the thermal switches 180, 182 are secured to the bracket 160 by screws 184; however, as one skilled in the art would appreciate, the thermal switches 180, 182 may be secured to the bracket by any suitable securing means, mechanical or otherwise, provided that the thermal switches remain in place on the bracket and good thermal conductivity is maintained between the switches 180, 182 and the bracket 160.

The thermal switches 180, 182 are operatively connected to a controller (not shown) of the ovens 115, 116, and comprise respective activation temperatures or set points at which the switches are activated to signal a malfunction of the fan 140 (FIG. 2) whenever the fan fails to move sufficient cooling air through the airflow pathway 130. In a typical embodiment, one thermal switch (e.g., the first thermal switch 180) has a first activation temperature and the other thermal switch (e.g., the second thermal switch 182) has a second activation temperature that is higher than the first activation temperature. Accordingly, the first thermal switch 180 is configured or activated to signal a malfunction of the fan 140 during a first relatively lower temperature appliance heating operation, such as a cooking and/or baking operation, and the second thermal switch 182 is configured or activated to signal a malfunction of the fan 140 during a second relatively higher temperature appliance heating operation, such as a self-cleaning operation. In some embodiments, the first thermal switch 180 has an activation temperature in the range of about 100° C. to about 120° C., and the second thermal switch 182 has an activation temperature in the range of about 110° C. to about 130° C. And in some such embodiments, the first thermal switch 180 has an activation temperature of about 110° C.+/−about 3° and the second thermal switch 182 has an activation temperature of about 121° C.+/−about 3°.

Because the first thermal switch 180 typically has a lower activation temperature than the second thermal switch 182, the switches operate on separate electrical circuits coinciding with the chosen heating operation. Having this arrangement, the separate circuits are individually activated based on which of the heating operations is chosen by the user, so that one of the thermal switches is always in a deactivated (i.e. nonfunctioning) state during the operative cycle of the chosen heating operation. For example, during the operative cycle of the first heating operation, the first thermal switch 180 would be in a functioning state and the second thermal switch 182 would be in a nonfunctioning state; and during the operative cycle of the second heating operation, the second thermal switch 182 would be in a functioning state and the first thermal switch 180 would be in a nonfunctioning state. Such an arrangement prevents the first thermal switch 180 from falsely signaling a fan malfunction/failure when the second relatively higher temperature appliance heating operation, which operates at a temperature exceeding the first thermal switch's activation temperature, is in progress. Otherwise, the first thermal switch 180 would undesirably shut shown the second appliance heating operation as soon as its lower activation temperature (compared to the second thermal switch 182 which has a higher activation temperature) was reached.

Still referring to FIGS. 3 and 5, the bracket 160 is mounted to a section of the interior frame 119 of the cooking range 100 in such a manner that at least a portion of the bracket 160 directly contacts the frame 119. In one embodiment, shown for example in FIG. 2, the bracket 160 is mounted to the upper section 119a of the frame 119. The bracket 160 secures the thermal switches 180, 182 at a location within the airflow pathway 130, so that when the fan is operating properly, the cooling air flows substantially around the thermal switches 180, 182 to maintain the thermal switches 180, 182 at a temperature below their respective activation temperatures. Additionally, the bracket 160 is configured to conduct heat directly from the frame 119 of the cooking range 100 to the thermal switches 180, 182 so that whenever the fan 140 (FIG. 2) fails to move the cooling air through the airflow pathway 130, the heating of the bracket by the frame raises the temperature sensed by the thermal switches so that the switches reach their respective activation temperatures relatively quickly. By this arrangement, the reaction time of each thermal switch in reaching its respective activation temperature is reduced relative to the reaction times of the same thermal switches used in conventional fan apparency arrangements (see below description of conventional fan apparency arrangements). The reduced reaction time is a result of the direct (conductive) heat transfer path between the oven walls and the thermal switches 180, 182 provided by the embodiments of the fan apparency arrangement 150 described herein. Said heat transfer path allows heat to travel rapidly and directly from the oven walls (i.e. the walls of the ovens 115, 116), to the frame 119, to the bracket 160 and then to the thermal switches 180, 182. Preferably, the bracket conducts heat substantially evenly from the frame 119 to both thermal switches 180, 182 to ensure that the reaction times for both switches are consistently reduced. To facilitate rapid heat conduction (i.e., rapid heat transfer from the frame 119 through the bracket 160 to the thermal switches 180, 182), the bracket 160 is typically made from aluminized steel; however, it should be noted that the bracket can be made from any other heat conducting material such as, for example, copper, brass, steel or aluminum.

In one embodiment, shown best in FIG. 4, the bracket 160 comprises a mounting surface 162 onto which the thermal switches 180, 182 are mounted, and two leg members 164, 165 (i.e., a plurality of leg members) extending from the mounting surface 162. In some such embodiments, at least one of the leg members includes a mounting appendage 166 that directly contacts the frame 119 and secures the bracket to the frame 119 of the cooking range 100. And in some such embodiments, the bracket 160 has two mounting appendages 166, 167 that contact the frame 119, where one mounting appendage is screwed (see screw 169) to the frame 119, while the other mounting appendage is tightly fitted into a securing member 170 defined by a portion of the frame 119. It should be noted that in alternative embodiments, both appendages 166, 167 could be screwed to the frame or fitted into corresponding securing members defined by or separately attached to the frame, or otherwise attached by any other known mechanical securing methods, such as welding, riveting, bolting, nailing, brazing, etc., so long as the bracket 160 is secured to the frame 119 in a manner which provides good thermal conductivity between bracket and frame.

Although the illustrated embodiment shows the bracket 160 having one mounting surface and two leg members, the bracket 160 may include more than two leg members and/or more than one mounting surface as shown, for example, in FIG. 6 (described in further detail below). It is also conceivable that the bracket include only one leg member. When the bracket 160 is mounted to the frame 119, the leg members 164, 165 space the mounting surface 162 of the bracket 160 away from the frame 119, so that cooling air is allowed to flow between the mounting surface 162 and the frame 119 to prevent obstruction of the airflow pathway 130 and allow cooling air to flow underneath the thermal switches 180, 182. Typically, the mounting surface 162 is spaced a distance (d) from the frame so that an interface 154 between the thermal switches 180, 182 and the bracket 160 is approximately centered relative to an adjacent section of the airflow pathway 130. In one embodiment, the distance (d) is approximately 0.2″ to approximately 1.2″; and in another embodiment the distance (d) is approximately 0.4″ to approximately 1″; and in a further embodiment the distance (d) is approximately 0.626″+/−approximately 0.15″.

FIG. 5 shows an alternative embodiment of the fan apparency arrangement 150 shown in FIGS. 3 and 4, where like numerals identify like parts. The fan apparency arrangement 150′ illustrated in FIG. 5 primarily differs from that shown in FIGS. 3 and 4 in that the arrangement includes one thermal switch 180 instead of two, and includes two mounting appendages 166, 167, both of which are screwed to the frame 119 of the appliance 100 to secure the bracket 160. Although both mounting appendages 166, 167 are depicted as being screwed to the frame 119, it should be noted that one or both of the appendages could be attached by any of the securing methods identified above with respect to the arrangement shown in FIGS. 3 and 4. The fan apparency arrangement 150′ shown in FIG. 5 is typically used in conjunction with single oven ranges.

Turning to FIG. 6, an alternative embodiment of the fan apparency bracket 160 shown in FIGS. 3 and 4 is illustrated, where like numerals identify like parts. The bracket 160′ shown in FIG. 6 primarily differs from the bracket shown in FIGS. 3 and 4 in that the bracket comprises four leg members 164, 164′, 165, 165′ instead of two, and two switch mounting surfaces 162,162′ (one for each switch 180, 182) instead of one. Additionally, the bracket 160′ includes an intermediate segment or frame contact point 168, which can function like an additional mounting appendage or simply rest unattached against the frame of the appliance. In some embodiments, the additional contact point 168 improves heat conduction via the bracket 160′ between the frame 119 (not shown) and the thermal switches 180, 182 (not shown). The bracket 160′ shown in FIG. 6 is typically used with double oven ranges.

Having thus described the fan apparency arrangement 150 and its various embodiments in conjunction with typical cooking ranges 100 employing said arrangement and embodiments, attention will now be given to an example of its operation. During operation of the cooking range 100, a user selects and activates a heating operation (e.g., a cooking/baking and/or self-cleaning operation) for one or both of the ovens 115, 116 via the controls 122 on the control panel 120. Activation of such an operation, in turn, activates the fan 140. Also, as noted above, selection of a particular heating operation (e.g. cooking/baking or self-cleaning) will maintain the thermal switch associated with the selected heating operation in a functioning state, while the thermal switch associated with the non-selected heating operation will be placed (or remain) in a nonfunctioning state. If the fan 140 is working properly, ambient or cooling air is drawn into the airflow pathway 130 and flows through the pathway 130 to cool desired components of the range 100 and maintain the thermal switches 180, 182 below their respective activation temperatures. If, however, the fan 140 malfunctions such that the supply of flowing cooling air generated by the fan 140 drops below an acceptable level or cease altogether, the thermal switches 180, 182 are heated. Depending upon which heating operation (e.g., cooking/baking or self-cleaning) was selected by the user and activated, if the functioning thermal switch (i.e., the first thermal switch 180 if a cooking or baking function is selected, or the second thermal switch 182 if a self-cleaning operation is selected) reaches its respective activation temperature, the switch signals the range's controller that the fan 140 is malfunctioning and the respective heating operation is terminated. Because the bracket 160 directly contacts the frame 119 of the cooking range 100 as described above, the bracket 160 will conduct heat directly from the frame 119 (which as noted above is in direct contact with the walls of ovens 115, 116) to the thermal switches 180, 182, causing the switches to heat up more rapidly during a fan malfunction in comparison to the same thermal switches used in conventional fan apparency arrangements (described in more detail below). By heating up more rapidly, the time (i.e., the reaction time) it takes each switch to reach its respective activation temperature during a fan malfunction is reduced, thus reducing the time it takes for the switch to signal a fan malfunction to the controller to terminate the activated heating operation(s).

The inventive embodiments of the fan apparency arrangements described herein offer advantages over conventional (i.e., prior art) fan apparency arrangements that use the same thermal switches, but do not arrange and position the switches in the inventive manner described above. In conventional fan apparency arrangements (not shown), the thermal switches 180, 182 would typically be attached to internal vent or duct covers and/or insulation retaining members, all of which are spaced away from the frame 119 and the oven cavities 115, 116. When a thermal switch is attached to an insulation retaining member, heat must travel from an oven cavity through a layer of insulation before reaching the retaining member and then the switch. And when a thermal switch is attached to an internal vent or duct cover, heat must travel from an oven cavity through/across the open space in the vent or duct before reaching the vent or duct cover and then the thermal switch. Accordingly, the time (t) required to transfer enough heat to the thermal switches for the switches to reach their respective activation temperatures (during a fan malfunction) using conventional arrangements is markedly greater than the time (t) required to accomplish same using any of the embodiments of the fan apparency arrangement 150 described herein. For example, the reaction times of the inventive fan apparency arrangements described herein during bake operations were about 6-8 minutes less than the reaction times of conventional fan apparency arrangements during bake operations (i.e., the reaction times were reduced from about 10-12 minutes to about 4 minutes). And the reaction times of the inventive fan apparency arrangements described herein during self-cleaning operations were about 0.5-1.5 minutes less than the reaction times of conventional fan apparency arrangements during self-cleaning operations (i.e., the reaction times were reduced from about 2-3 minutes to about 1.5 minutes). Additionally, the inventive fan apparency arrangements described herein are easier to assemble and install into their respective appliances in comparison to conventional arrangements, thereby providing a savings in manufacturing and maintenance costs.

Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.