CA1142232A - Damper activation in a combined microwave and electric heating oven - Google Patents
Damper activation in a combined microwave and electric heating ovenInfo
- Publication number
- CA1142232A CA1142232A CA000349459A CA349459A CA1142232A CA 1142232 A CA1142232 A CA 1142232A CA 000349459 A CA000349459 A CA 000349459A CA 349459 A CA349459 A CA 349459A CA 1142232 A CA1142232 A CA 1142232A
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- Canada
- Prior art keywords
- oven
- air flow
- microwave
- oven cavity
- damper
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
A combination microwave and electric oven includes a damper mechanism for selectively and automatically introducing a forced air flow into an oven cavity. A timer is provided for determining a microwave cooking period, wherein a magnetron is energized to perform the microwave cooking operation. The damper mechanism is associated with the timer so that the damper is automatically placed in a first position wherein the forced air flow is introduced into the oven cavity when the timer is wound up to select a preferred microwave cooking period. When the preselected time period has been counted by the timer, micro-wavegenerating is terminated and the damper automatically assumes a second position wherein the forced air flow is prevented from entering the oven cavity. The damper is placed in the second position when electric cooking operations are performed so that the interior of the oven cavity can be maintained at high temperatures without excessive energy consumption.
A combination microwave and electric oven includes a damper mechanism for selectively and automatically introducing a forced air flow into an oven cavity. A timer is provided for determining a microwave cooking period, wherein a magnetron is energized to perform the microwave cooking operation. The damper mechanism is associated with the timer so that the damper is automatically placed in a first position wherein the forced air flow is introduced into the oven cavity when the timer is wound up to select a preferred microwave cooking period. When the preselected time period has been counted by the timer, micro-wavegenerating is terminated and the damper automatically assumes a second position wherein the forced air flow is prevented from entering the oven cavity. The damper is placed in the second position when electric cooking operations are performed so that the interior of the oven cavity can be maintained at high temperatures without excessive energy consumption.
Description
The present invention relates to a combination micro-wave and electric oven and~ more particula~ to a damper activating mechanism in a combination microwave and electric oven.
A combined microwave and electric oVen has been devel-oped which includes a microwave generating source for microwave cooking purposes and an electric heater for electric cooking purposes. When cooking in the microwave mode, it is necessary to introduce an air flow into the oven cavity for recirculation purposes. Conversely, when cooking electrically there must be no air flow for otherwise cooking temperatures within the oven could not be maintained without excessive energy consumption.
Air flow is required, however, outside the oven cavity to ~rotect the microwave generator from the high temperatures otherwise induced by the electric heater.
To enhance cooking efficien~y~ it is desirable that the microwave cooking be performed first, followed immediately afterwards by electric cooking.
Accordingly! an object of the present invention is to provide a novel damper mechanism in a combination microwave and electric oven.
Another object of the present invention is to provide an automatic damper activating mechanism associated with a cook-ing timer in a combination microwave and electric oven.
Other objects and further scope of applicability of the present invention will become apparent from the detailed descrip-tion given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the inVention, are given by way of illustration only, since various changes and modiications within the spirit and scope of the invention will become ~ppaxent to those skilled in the art from this detailed descxiption.
To achieve the above objects pursuant to an embodiment of the present invention, a blower fan system is provided for creating a forced air flow for cooling the microwave generator.
The blower fan system is continuously energized during both microwave and electric cookin~ operations. A damper mechanism is provided for selectively introducing the forced air flow into the oven cavity.
In a preferred form, a microwave control timer mechan-ism is associated with the damper mechanism so that the damper mechanism allows the introduction of forced air into the oven - cavity during periods of microwave cooking but prevents that air flow during periods of electric cooking.
According to the present invention, then, there is provided a combination microwave and electric oven comprising:
' an oven wall defining an oven cavity therein; microwave generat-ing means disposed externally of the oven cavity for microwave cooking operations;electric heater means for electric cooking ;20~ ; operations; blower means for creating a forced air flow for cooling the microwave generating means; air flow guide means for directing the forced air flow toward the oven cavity7 '~ damper means disposed in the air flow guide means, the damper means being selectively actuatable between a first position wherein the forced air flow is introduced into the oven cavity and a second position wherein the forced air flow is not intro-duced into the oven cavity; first timer means for selecting a ; period of microwave cooking whereby the microwave generating ; means are energized; and drive means associated with the first timer means for actuating the damper means, whexeby the damper
A combined microwave and electric oVen has been devel-oped which includes a microwave generating source for microwave cooking purposes and an electric heater for electric cooking purposes. When cooking in the microwave mode, it is necessary to introduce an air flow into the oven cavity for recirculation purposes. Conversely, when cooking electrically there must be no air flow for otherwise cooking temperatures within the oven could not be maintained without excessive energy consumption.
Air flow is required, however, outside the oven cavity to ~rotect the microwave generator from the high temperatures otherwise induced by the electric heater.
To enhance cooking efficien~y~ it is desirable that the microwave cooking be performed first, followed immediately afterwards by electric cooking.
Accordingly! an object of the present invention is to provide a novel damper mechanism in a combination microwave and electric oven.
Another object of the present invention is to provide an automatic damper activating mechanism associated with a cook-ing timer in a combination microwave and electric oven.
Other objects and further scope of applicability of the present invention will become apparent from the detailed descrip-tion given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the inVention, are given by way of illustration only, since various changes and modiications within the spirit and scope of the invention will become ~ppaxent to those skilled in the art from this detailed descxiption.
To achieve the above objects pursuant to an embodiment of the present invention, a blower fan system is provided for creating a forced air flow for cooling the microwave generator.
The blower fan system is continuously energized during both microwave and electric cookin~ operations. A damper mechanism is provided for selectively introducing the forced air flow into the oven cavity.
In a preferred form, a microwave control timer mechan-ism is associated with the damper mechanism so that the damper mechanism allows the introduction of forced air into the oven - cavity during periods of microwave cooking but prevents that air flow during periods of electric cooking.
According to the present invention, then, there is provided a combination microwave and electric oven comprising:
' an oven wall defining an oven cavity therein; microwave generat-ing means disposed externally of the oven cavity for microwave cooking operations;electric heater means for electric cooking ;20~ ; operations; blower means for creating a forced air flow for cooling the microwave generating means; air flow guide means for directing the forced air flow toward the oven cavity7 '~ damper means disposed in the air flow guide means, the damper means being selectively actuatable between a first position wherein the forced air flow is introduced into the oven cavity and a second position wherein the forced air flow is not intro-duced into the oven cavity; first timer means for selecting a ; period of microwave cooking whereby the microwave generating ; means are energized; and drive means associated with the first timer means for actuating the damper means, whexeby the damper
- 2 -.. ~ .
.' ~1~2232 means are placed in the first position when the microwave generating means are energized.
According to a further aspect of the present invention there is also provided a combination microwave and electric oven comprising an oven wall defining an oven cavity therein, micro-wave generatingmeans disposed externally of the oven cavity for microwave cooking operations, electric heater means for performing electric cooking operations, blower means for creating a forced air flow for cooling the microwave generating means, air flow guide means for directing the forced air flow toward the oven cavity, damper means disposed in the air flow guide means, the damper means being selectively actuatable between a first position wherein the forced air flow is introduced into the oven cavity and a second position wherein the forced air flow is not intro-duced into the oven cavity, timer means for selecting a first time period during which the microwave generating means are energized, and a second time period during which the electric heater means are energized, first drive means associated with the timer means for energizing the blower means during the first 2:0 and second time periods, and second drive means associated with the timer means for actuating the damper means into the first position during the first time period.
: According to yet another aspect of the present invention, there is provided a combined microwave and electric heating oven comprising an oven wall defining an oven cavity therein, microwave generating means disposed at the outside of the oven cavity for introducing microwave energy into the oven cavity for performing a microwave cooking operation, electric heater means disposed in the oven cavity for performing an electric : 30 heating cooking operation, blower fan means operatively ~o ~ .
1~4ZZ3~2 associated with the microwave generating means for creating a forced air flow for cooling the microwave generating means, air flow c3uide means communicating with the oven cavity and a zone surrounding the oven cavity, the air flow guide means directing the forced air flow toward the oven cavity and the zone surrounding the oven cavity, damper means disposed in the air flow guide means, the damper means being adapted to selectively channel the forced air flow to either the oven cavity or the zone surrounding the oven cavity, and time period determination means operatively associated with the damper means for automatically changing the position of the damper means within the air flow guide means depending on the type of cooking cycle which is being energized.
Embodiments of the present invention will now be described in greater detail and will be better understood when read in conjunction with the following drawings in which:
Figure 1 is a front elevational view of an embodiment of a combination microwave and electric oven as described herein;
Figure 2 is a perspective view of the combination microwave and electric oven of Figure 1, wherein an outer casing is removed;
- 3a -11~2~:3Z
Figure 3 is a frontal view of an embodiment of a damper mechanism included in the combination oven of Figure l;
Figure 4 is a schematic circuit diagram of the combina-tion microwave and electric oven of Figure l; and Figure 5 is a perspective view of another embodiment of the damper mechanism included in the combination microwave and electric oven of Figure 1.
Figures 1 and 2 schematically illustrate an embodiment of a combination microwave and electric oven.
The combination oven comprises generally a casing 10 and an oven wall 12 defining an oven cavity. A tray 14 is remov-ably disposed at the bottom of the oven cavity for supporting a foodstuff to be cooked, and an electric heater 16 is disposed at an upper section of the oven cavity for performing the electric cooking operations. The combined microwave and electric oven further comprises a control panel 18 upon which a first timer 20, a second timer 22 and a cook start switch 24 are provided.
Timers 20 and 22 are used to select electric and microwave cook-ing periods, respectively.
A magnetron 26 is secured to side wall 12 of the oven cavity. The microwave energy generated by the magnetron 26 is introduced into the oven cavity via a waveguide 28, A blower fan 30 is provided for drawing fresh air through air inlet open-ings 32 and developing a forced air flow. The forced air flow is directed to magnetron 26 for cooling purposes and is also selectively introduced into the oven cavity via a damper mechanism 34 and an air duct 36. Damper mechanism 34 is associated with second timer 22 so that the forced air flow is introduced into the oven cavity only when the oven is in the microwave cooking mode.
. . .
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Air duct 36 includes one inlet 36~ $oX ~eceiving the forced air flow (X~, and two outlets 362 and 364 for select-ively developing forced air flows (Y) and (Z).
Referring now to Figure 3, there is shown the relation-ship between second ti~er 22 and the damper mechanism 34. Like elements corresponding to those of Figure 2 are indicated by like numerals.
Damper mechanism 34 includes a damper plate 38 disposed in air duct 36. The damper plate 38 is rotatably secured to a shaft 40 and is biased by a spring 42 to normally rest at the position indicated by solid lines in Figure 3. Accordingly, forced air flow (X) introduced normally through inlet 360 is directed to outlet 362 to create forced air flow (Y). Forced air flow (Y) is passed through a gap formed between the casing 10 and the oven wall 12, and is exhausted through openings 44 formed in the rear wall of casing 10 (see Figure 2). Accordingly, the air flow (Y) is not normally introduced into the oven cavity.
When timer 22 is rotated to the desired setting through the use of a timer knob 46, a cam 48 fixed to a timer shaft 50 -is rotated in the clockwise direction, thereby depressing a ~; roller 52 downwardly. Roller 52 is integrally fixed to a roller lever 54 which is rotatably supported by a sha~t 56. Accordingly, when second timer 22 is rotated to the desired setting corres-ponding to a desired microwave cooking period, roller lever 54 is pivoted into the position shown by the broken lines in Figure 3. Damper plate 38 is thusly pivoted into the position shown by the broken lines in Figure 3 due to the action of rod 58 and forced air flow (X~ introduced through the inlet 360 is directed to outlet 364 ko create forced air ~low (Z).
Forced air flow (Z) is introduced into the oven cavity , 11~2Z32 for recirculation purposes, The ai~ is then exhausted from the cavity via exhaust openings 60 formed into an upper portion of oven wall 12, an exhaust duct 62 secured to oven wall 12, and exhaust openings 64 formed in the rear wall of casing 10 (see Figure 2). Accordingly, forced air flow ~Z~ is introduced into the oven cavity only when microwave cooking operations are being performed. When microwave cooking is completed following the lapse of the time period selected by second timer 22, damper plate 38 is returned to its normal position by spring 42, thereby preventing any further flow of forced air into the oven cavity.
Referring now to Figure 4, there is schematically illustrated the circuitr~ of the combination oven referred to herein. Like elements corresponding to those of Figures 1 and 2 are indicated by like numerals.
A latch switch 66 is associated with the o~en door such that a movable contact of the switch is connected to a first terminal 660 when the oven door is opened and to a second ~ termlnal 662 when the oven door is closed. A safety switch 68 ; ~ is also associated with the oven door to be closed when the oven door is closed. ~imer switches 70 and 72 are associated with the second timer 22 in such a manner that movable contacts thereof are connected to first terminals 700 and 720, respectively, when second timer 22 is rotated or wound up. Another timer switch 74 is associated with the first timer 20 so that timer switch 74 is closed when first timer 20 is wound up. First timer 20 includes a timer motor 200 for controlling the electric cooking time period whereby timer switch 74 is opened when the preselected cooking $ime period has been counted by timer motor 200. The second timer 22 includes another timer motor 220 for controlling the microwave cooking time period, whereby the movable contacts of timer ~' '~
.
, 114~:Z32 switches 70 and 72 are connected to second terminals 702 and 722, respectively, when the preselected time period has been counted by timer motor 220. Figure 4 illustrates the initial condition wherein neither first timer 20 nor second timer 22 have been wound up.
The control circuit of Figure 4 further comprises a transformer 76 for supplying power to magnetron 26, and a blower motor 300 for activating blower fan 30.
For the purposes of illustration, it will be assumed that a roast beef is to be prepared. As mentioned previously, it is preferable that microwave cooking be performed first, to be followed therafter by electric cooking. Second timer 22 is rotated to select a desired microwave cooking period and first timer 20 is then rotated to select a desired electric cooking period. After placing the meat within the oven cavity, the oven door is tightly closed to connect the movable contact of latch switch 66 to second terminal 662, and toclose safety switch 68.
Cook start switch 24 is then closed, and transformer 76 and timer motor 220 receive power through the first terminal 700 of ~20 timer switch 70. Blower motor 300 is activated through the first terminal 720 of timer switch 72. Accordingly, microwave cooking is performed firstly.
While microwave cooking is being per~ormed, damper plate 38 is positioned as shown by the broken line in Figure 3, such that forced air flow tZ) is introduced into the oven cavity for recirculation purposes.
After microwave cooking has been conducted for the predetermined period of time selected b~ second timer 22, the movable contacts of timer switches 70 and 72 are connected to second terminals 702 and 722, respectively, to terminate micro-` ..'``' .!
- ' ' ` '~
11~2Z32 wave generation. At the same time, dampex plate 38 is returned to its normal position by spring 42 thereby preventing the introduction of forced air into the oven cavity.
~pon completion of the microwave cooking operations, electric heater 16 and timer motor 200 receive power through the second terminal 702 of timer switch 70 and timer switch 74.
Blower motor 300 is activated through the second terminal 722 of timer switch 72. Accordingly, electric cooking operations !
are started automatically immediately upon completion of micro-wave cooking operations. It will be clear that while electric cooking operations are being conducted, forced air is not intro-duced into the oven cavity. However, the area between oven cavity 12 and casing 10 is cooled by forced air flows (X) and (Y).
When the electric cooking has been conducted for the period of time selected by first timer 20, timer switch 74 is switched off to complete the series of cooking operations.
Figure 5 illustrates another example of the damper ; ~ mechanism. Like elements corresponding to those of Figure 3 are indicated by like numerals.
20 ~ The damper plate 38 is disposed in the air duct 36 and is rotatably supported by a shaft 80. A damper lever 82 is secured to one end o~ the shaft 80 whereby the damper plate 38 rotates in unison with damper lever 82. Damper lever 82 is associated with a roller arm 84 through a communication rod 86.
When second timer 22 is rotated, communication rod 86 is pulled in the direction shown by the arrow in Figure 5 in response to the rotation of cam 48. Accordingly, damper plate 38 is urged into the position shown by the solid lines in Figure 5 to allow the introduction of forced air (Z) into the oven cavity. A
spring 88 biases damper plate 38 towards the normal position ~ - 8 -ll~Z;23Z
shown by the broken lines in Figuxe 5, whereby the flow of forced air into the oven cavity is prevented during electric cooking operations.
Where it is desired to $irst perform electric cooking and then the microwave cooking, the control circuit of Figure 4 may be modified to assign a priority to the electric cooking operations. Accordingly the damper mechanism may be actuated by rotation of the timer used to select electric cooking time periods 60 that it is norma]ly open during periods of microwave cooking. Upon actuation of the electric timer, then, the damper is closed to prevent the circulation of air in the oven cavity during periods of electric cooking.
Although in the foregoing embodiments a mechanical timer has been described, the present invention can be applied to a combination oven including a digital timer system. A
plunger mechanism may be associated with the damper mechanism to be activated during microwave cooking operations to open the damper mechanism to the oven cavity to allow for the circu-lation of forced air therein.
~he invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure ~rom the spirit and scope o~
i the invention, and all such modifications are intended to be !~ :
included within the scope of the following claims.
.' ~1~2232 means are placed in the first position when the microwave generating means are energized.
According to a further aspect of the present invention there is also provided a combination microwave and electric oven comprising an oven wall defining an oven cavity therein, micro-wave generatingmeans disposed externally of the oven cavity for microwave cooking operations, electric heater means for performing electric cooking operations, blower means for creating a forced air flow for cooling the microwave generating means, air flow guide means for directing the forced air flow toward the oven cavity, damper means disposed in the air flow guide means, the damper means being selectively actuatable between a first position wherein the forced air flow is introduced into the oven cavity and a second position wherein the forced air flow is not intro-duced into the oven cavity, timer means for selecting a first time period during which the microwave generating means are energized, and a second time period during which the electric heater means are energized, first drive means associated with the timer means for energizing the blower means during the first 2:0 and second time periods, and second drive means associated with the timer means for actuating the damper means into the first position during the first time period.
: According to yet another aspect of the present invention, there is provided a combined microwave and electric heating oven comprising an oven wall defining an oven cavity therein, microwave generating means disposed at the outside of the oven cavity for introducing microwave energy into the oven cavity for performing a microwave cooking operation, electric heater means disposed in the oven cavity for performing an electric : 30 heating cooking operation, blower fan means operatively ~o ~ .
1~4ZZ3~2 associated with the microwave generating means for creating a forced air flow for cooling the microwave generating means, air flow c3uide means communicating with the oven cavity and a zone surrounding the oven cavity, the air flow guide means directing the forced air flow toward the oven cavity and the zone surrounding the oven cavity, damper means disposed in the air flow guide means, the damper means being adapted to selectively channel the forced air flow to either the oven cavity or the zone surrounding the oven cavity, and time period determination means operatively associated with the damper means for automatically changing the position of the damper means within the air flow guide means depending on the type of cooking cycle which is being energized.
Embodiments of the present invention will now be described in greater detail and will be better understood when read in conjunction with the following drawings in which:
Figure 1 is a front elevational view of an embodiment of a combination microwave and electric oven as described herein;
Figure 2 is a perspective view of the combination microwave and electric oven of Figure 1, wherein an outer casing is removed;
- 3a -11~2~:3Z
Figure 3 is a frontal view of an embodiment of a damper mechanism included in the combination oven of Figure l;
Figure 4 is a schematic circuit diagram of the combina-tion microwave and electric oven of Figure l; and Figure 5 is a perspective view of another embodiment of the damper mechanism included in the combination microwave and electric oven of Figure 1.
Figures 1 and 2 schematically illustrate an embodiment of a combination microwave and electric oven.
The combination oven comprises generally a casing 10 and an oven wall 12 defining an oven cavity. A tray 14 is remov-ably disposed at the bottom of the oven cavity for supporting a foodstuff to be cooked, and an electric heater 16 is disposed at an upper section of the oven cavity for performing the electric cooking operations. The combined microwave and electric oven further comprises a control panel 18 upon which a first timer 20, a second timer 22 and a cook start switch 24 are provided.
Timers 20 and 22 are used to select electric and microwave cook-ing periods, respectively.
A magnetron 26 is secured to side wall 12 of the oven cavity. The microwave energy generated by the magnetron 26 is introduced into the oven cavity via a waveguide 28, A blower fan 30 is provided for drawing fresh air through air inlet open-ings 32 and developing a forced air flow. The forced air flow is directed to magnetron 26 for cooling purposes and is also selectively introduced into the oven cavity via a damper mechanism 34 and an air duct 36. Damper mechanism 34 is associated with second timer 22 so that the forced air flow is introduced into the oven cavity only when the oven is in the microwave cooking mode.
. . .
~ ~ 4 -., ~ ' ' .
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Air duct 36 includes one inlet 36~ $oX ~eceiving the forced air flow (X~, and two outlets 362 and 364 for select-ively developing forced air flows (Y) and (Z).
Referring now to Figure 3, there is shown the relation-ship between second ti~er 22 and the damper mechanism 34. Like elements corresponding to those of Figure 2 are indicated by like numerals.
Damper mechanism 34 includes a damper plate 38 disposed in air duct 36. The damper plate 38 is rotatably secured to a shaft 40 and is biased by a spring 42 to normally rest at the position indicated by solid lines in Figure 3. Accordingly, forced air flow (X) introduced normally through inlet 360 is directed to outlet 362 to create forced air flow (Y). Forced air flow (Y) is passed through a gap formed between the casing 10 and the oven wall 12, and is exhausted through openings 44 formed in the rear wall of casing 10 (see Figure 2). Accordingly, the air flow (Y) is not normally introduced into the oven cavity.
When timer 22 is rotated to the desired setting through the use of a timer knob 46, a cam 48 fixed to a timer shaft 50 -is rotated in the clockwise direction, thereby depressing a ~; roller 52 downwardly. Roller 52 is integrally fixed to a roller lever 54 which is rotatably supported by a sha~t 56. Accordingly, when second timer 22 is rotated to the desired setting corres-ponding to a desired microwave cooking period, roller lever 54 is pivoted into the position shown by the broken lines in Figure 3. Damper plate 38 is thusly pivoted into the position shown by the broken lines in Figure 3 due to the action of rod 58 and forced air flow (X~ introduced through the inlet 360 is directed to outlet 364 ko create forced air ~low (Z).
Forced air flow (Z) is introduced into the oven cavity , 11~2Z32 for recirculation purposes, The ai~ is then exhausted from the cavity via exhaust openings 60 formed into an upper portion of oven wall 12, an exhaust duct 62 secured to oven wall 12, and exhaust openings 64 formed in the rear wall of casing 10 (see Figure 2). Accordingly, forced air flow ~Z~ is introduced into the oven cavity only when microwave cooking operations are being performed. When microwave cooking is completed following the lapse of the time period selected by second timer 22, damper plate 38 is returned to its normal position by spring 42, thereby preventing any further flow of forced air into the oven cavity.
Referring now to Figure 4, there is schematically illustrated the circuitr~ of the combination oven referred to herein. Like elements corresponding to those of Figures 1 and 2 are indicated by like numerals.
A latch switch 66 is associated with the o~en door such that a movable contact of the switch is connected to a first terminal 660 when the oven door is opened and to a second ~ termlnal 662 when the oven door is closed. A safety switch 68 ; ~ is also associated with the oven door to be closed when the oven door is closed. ~imer switches 70 and 72 are associated with the second timer 22 in such a manner that movable contacts thereof are connected to first terminals 700 and 720, respectively, when second timer 22 is rotated or wound up. Another timer switch 74 is associated with the first timer 20 so that timer switch 74 is closed when first timer 20 is wound up. First timer 20 includes a timer motor 200 for controlling the electric cooking time period whereby timer switch 74 is opened when the preselected cooking $ime period has been counted by timer motor 200. The second timer 22 includes another timer motor 220 for controlling the microwave cooking time period, whereby the movable contacts of timer ~' '~
.
, 114~:Z32 switches 70 and 72 are connected to second terminals 702 and 722, respectively, when the preselected time period has been counted by timer motor 220. Figure 4 illustrates the initial condition wherein neither first timer 20 nor second timer 22 have been wound up.
The control circuit of Figure 4 further comprises a transformer 76 for supplying power to magnetron 26, and a blower motor 300 for activating blower fan 30.
For the purposes of illustration, it will be assumed that a roast beef is to be prepared. As mentioned previously, it is preferable that microwave cooking be performed first, to be followed therafter by electric cooking. Second timer 22 is rotated to select a desired microwave cooking period and first timer 20 is then rotated to select a desired electric cooking period. After placing the meat within the oven cavity, the oven door is tightly closed to connect the movable contact of latch switch 66 to second terminal 662, and toclose safety switch 68.
Cook start switch 24 is then closed, and transformer 76 and timer motor 220 receive power through the first terminal 700 of ~20 timer switch 70. Blower motor 300 is activated through the first terminal 720 of timer switch 72. Accordingly, microwave cooking is performed firstly.
While microwave cooking is being per~ormed, damper plate 38 is positioned as shown by the broken line in Figure 3, such that forced air flow tZ) is introduced into the oven cavity for recirculation purposes.
After microwave cooking has been conducted for the predetermined period of time selected b~ second timer 22, the movable contacts of timer switches 70 and 72 are connected to second terminals 702 and 722, respectively, to terminate micro-` ..'``' .!
- ' ' ` '~
11~2Z32 wave generation. At the same time, dampex plate 38 is returned to its normal position by spring 42 thereby preventing the introduction of forced air into the oven cavity.
~pon completion of the microwave cooking operations, electric heater 16 and timer motor 200 receive power through the second terminal 702 of timer switch 70 and timer switch 74.
Blower motor 300 is activated through the second terminal 722 of timer switch 72. Accordingly, electric cooking operations !
are started automatically immediately upon completion of micro-wave cooking operations. It will be clear that while electric cooking operations are being conducted, forced air is not intro-duced into the oven cavity. However, the area between oven cavity 12 and casing 10 is cooled by forced air flows (X) and (Y).
When the electric cooking has been conducted for the period of time selected by first timer 20, timer switch 74 is switched off to complete the series of cooking operations.
Figure 5 illustrates another example of the damper ; ~ mechanism. Like elements corresponding to those of Figure 3 are indicated by like numerals.
20 ~ The damper plate 38 is disposed in the air duct 36 and is rotatably supported by a shaft 80. A damper lever 82 is secured to one end o~ the shaft 80 whereby the damper plate 38 rotates in unison with damper lever 82. Damper lever 82 is associated with a roller arm 84 through a communication rod 86.
When second timer 22 is rotated, communication rod 86 is pulled in the direction shown by the arrow in Figure 5 in response to the rotation of cam 48. Accordingly, damper plate 38 is urged into the position shown by the solid lines in Figure 5 to allow the introduction of forced air (Z) into the oven cavity. A
spring 88 biases damper plate 38 towards the normal position ~ - 8 -ll~Z;23Z
shown by the broken lines in Figuxe 5, whereby the flow of forced air into the oven cavity is prevented during electric cooking operations.
Where it is desired to $irst perform electric cooking and then the microwave cooking, the control circuit of Figure 4 may be modified to assign a priority to the electric cooking operations. Accordingly the damper mechanism may be actuated by rotation of the timer used to select electric cooking time periods 60 that it is norma]ly open during periods of microwave cooking. Upon actuation of the electric timer, then, the damper is closed to prevent the circulation of air in the oven cavity during periods of electric cooking.
Although in the foregoing embodiments a mechanical timer has been described, the present invention can be applied to a combination oven including a digital timer system. A
plunger mechanism may be associated with the damper mechanism to be activated during microwave cooking operations to open the damper mechanism to the oven cavity to allow for the circu-lation of forced air therein.
~he invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure ~rom the spirit and scope o~
i the invention, and all such modifications are intended to be !~ :
included within the scope of the following claims.
Claims (14)
1. A combination microwave and electric oven comprising:
an oven wall defining an oven cavity therein;
microwave generating means disposed externally of the oven cavity for microwave cooking operations;
electric heater means for electric cooking operations;
blower means operatively associated with the microwave generating means for creating a forced air flow for cooling said microwave generating means;
air flow guide means for directing said forced air flow toward said oven cavity;
damper means disposed in said air flow guide means, said damper means being selectively actuatable between a first position wherein said forced air flow is introduced into said oven cavity and a second position wherein said forced air flow is not introduced into said oven cavity;
first timer means for selecting a period of microwave cooking whereby said microwave generating means are energized;
and drive means associated with said first timer means for actuating said damper means, whereby said damper means are placed in said first position when said microwave generating means are energized.
an oven wall defining an oven cavity therein;
microwave generating means disposed externally of the oven cavity for microwave cooking operations;
electric heater means for electric cooking operations;
blower means operatively associated with the microwave generating means for creating a forced air flow for cooling said microwave generating means;
air flow guide means for directing said forced air flow toward said oven cavity;
damper means disposed in said air flow guide means, said damper means being selectively actuatable between a first position wherein said forced air flow is introduced into said oven cavity and a second position wherein said forced air flow is not introduced into said oven cavity;
first timer means for selecting a period of microwave cooking whereby said microwave generating means are energized;
and drive means associated with said first timer means for actuating said damper means, whereby said damper means are placed in said first position when said microwave generating means are energized.
2. The combination oven of claim 1, wherein said damper means assume said second position when said microwave generating means are not energized.
3. The combination oven of claim 2, further compris-ing:
second timer means for selecting a period of electric heating cooking whereby said electric heater means are energized.
second timer means for selecting a period of electric heating cooking whereby said electric heater means are energized.
4. The combination oven of claim 3, further comprising:
first control means for assigning a priority to said microwave cooking whereby said microwave generating means are first energized for said period selected by said first timer means and then said electric heater means are energized for said period selected by said second timer means.
first control means for assigning a priority to said microwave cooking whereby said microwave generating means are first energized for said period selected by said first timer means and then said electric heater means are energized for said period selected by said second timer means.
5. The combination oven of claim 4, further comprising:
second control means for energizing said blower means when either said microwave generating means or said electric heater means are energized.
second control means for energizing said blower means when either said microwave generating means or said electric heater means are energized.
6. A combination microwave and electric oven-cavity comprising:
an oven wall defining an oven cavity therein;
microwave generating means disposed externally of the oven cavity for microwave cooking operations;
electric heater means for performing electric cooking operations;
blower means for creating a forced air flow for cool-ing said microwave generating means;
air flow guide means for directing said forced air flow toward said oven cavity;
damper means disposed in said air flow guide means, said damper means being selectively actuatable between a first position wherein said forced air flow is introduced into said oven cavity and a second position wherein said forced air flow is not introduced into said oven cavity;
timer means for selecting a first time period during which said microwave generating means are energized, and a second time period during which said electric heater means are energized;
first drive means associated with said timer means for energizing said blower means during said first and second time periods; and second drive means associated with said timer means for actuating said damper means into said first position during said first time period.
an oven wall defining an oven cavity therein;
microwave generating means disposed externally of the oven cavity for microwave cooking operations;
electric heater means for performing electric cooking operations;
blower means for creating a forced air flow for cool-ing said microwave generating means;
air flow guide means for directing said forced air flow toward said oven cavity;
damper means disposed in said air flow guide means, said damper means being selectively actuatable between a first position wherein said forced air flow is introduced into said oven cavity and a second position wherein said forced air flow is not introduced into said oven cavity;
timer means for selecting a first time period during which said microwave generating means are energized, and a second time period during which said electric heater means are energized;
first drive means associated with said timer means for energizing said blower means during said first and second time periods; and second drive means associated with said timer means for actuating said damper means into said first position during said first time period.
7. A combined microwave and electric heating oven comprising an oven wall defining an oven cavity therein, microwave generating means disposed at the outside of the oven cavity for introducing microwave energy into the oven cavity for performing a microwave cooking operation, electric heater means disposed in said oven cavity for performing an electric heating cooking operation, blower fan means operatively associated with the micro-wave generating means for creating a forced air flow for cooling the microwave generating means, air flow guide means communicating with the oven cavity and a zone surrounding said oven cavity, said air flow guide.
means directing said forced air flow toward said oven cavity and the zone surrounding said oven cavity, damper means disposed in said air flow guide means, said damper means being adapted to selectively channel the forced air flow to either the oven cavity or the zone surrounding the oven cavity, and time period determination means operatively associated with said damper means for automatically changing the position of the damper means within the air flow guide means depending on the type of cooking cycle which is being energized.
means directing said forced air flow toward said oven cavity and the zone surrounding said oven cavity, damper means disposed in said air flow guide means, said damper means being adapted to selectively channel the forced air flow to either the oven cavity or the zone surrounding the oven cavity, and time period determination means operatively associated with said damper means for automatically changing the position of the damper means within the air flow guide means depending on the type of cooking cycle which is being energized.
8. The combined microwave and electric heating oven of claim 7 wherein when the microwave cooking operation is being performed the damper mechanism is placed in a first position wherein the forced air flow is introduced into the oven cavity, and when the electric heating cooking operation is being performed the damper means is placed in a second position wherein the forced air flow is introduced into the zone surrounding the oven cavity.
9. The combined microwave and electric heating oven of claim 7 wherein the electric heater means is disposed in the upper portion of the oven cavity.
10. The combined microwave and electric heating oven of claim 9 wherein the zone surrounding the oven cavity is a gap formed between the oven wall and the casing surrounding the oven wall.
11. The combined microwave and electric heating oven of claim 10 wherein vent means are provided in the casing for removing the forced air flow from the zone surrounding the oven cavity.
12. The combined microwave and electric heating oven of claim 7 wherein an exhaust duct is provided for removing the forced air flow from the oven cavity.
13. The combined microwave and electric heating oven of claim 7 wherein in a normal operating condition the damper means is spring biased to channel the forced air flow into the zone surrounding the oven cavity and wherein, in the microwave cooking operation the damper means is automatically rotated against the bias to thereby channel the forced air flow into the oven cavity.
14. The combined microwave and electric heating oven of claim 7 wherein the time period determination means includes a first timer for determining a cooking time period in the electric heating cooking mode and a second timer for determining a cooking time period in the microwave cooking mode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000349459A CA1142232A (en) | 1980-04-09 | 1980-04-09 | Damper activation in a combined microwave and electric heating oven |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000349459A CA1142232A (en) | 1980-04-09 | 1980-04-09 | Damper activation in a combined microwave and electric heating oven |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1142232A true CA1142232A (en) | 1983-03-01 |
Family
ID=4116669
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000349459A Expired CA1142232A (en) | 1980-04-09 | 1980-04-09 | Damper activation in a combined microwave and electric heating oven |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1142232A (en) |
-
1980
- 1980-04-09 CA CA000349459A patent/CA1142232A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |