GB2185876A - Electric cooker - Google Patents

Abstract

An electric cooker has a cooker main body 13, a container 9 disposed within the cooker main body and having an opening portion provided in the upper portion thereof, a cover 32 for covering the upper opening portion of the container 9, a lower heater 10, 11 provided in the lower portion of the container, an upper heater 38 disposed in the upper portion within the cover and a rack 54 detachably mounted on said container. The container is pan-shaped and a temperature controlling apparatus is disposed on the bottom portion of the container. A means for energizing and controlling said upper heater and lower heater is provided so that the cookings including oven cooking, grill cooking, pan cooking, steam cooking and soon may be performed with one cooker. <IMAGE>

Description

SPECIFICATION Electric cooker Background of the Invention The present invention relates to an electric cooker comprising a cooker main body, a container disposed within the cooker main body and having an opening portion provided in the upper portion thereof, a cover for covering the upper opening portion of the container, a lower heater provided in the lower portion of the container, an upper heater disposed in the upper portion within the cover.

Conventionally this type of electric cooker was of such construction as shown in Fig. 8. Namely, this electric cooker had a heater 2 built-in in the lower portion of the frying-pan-shaped container 1, an upper heater 4 provided in the cover 3 for covering the container 1, and a detachable thermostatic controlling apparatus 7, which had a temperature detecting probe 5, a pair of power terminals 6 disposed thereon, engaged with the concave portion 8 of the container 1 so as to do the fryingpan cooking. Further, this electric heater had the thermostatic controlling apparatus 7 engaged with the upper heater 4 of the cover 4 to perform the oven cooking.

However, in the electric heater of such construction as described hereinabove, the uniform roasting color for an article to be cooked could not be provided, because the heating operation was performed only by the upper heater 4 during the oven cooking. When the upper heater 4 was arranged above the cooked, only the top face of the cooked was cooked with the lower portion thereof remaining uncooked. Also, when the upper heater 4 was disposed sideways of the cooked, the central portion of the cooked remained uncooked, thus resulting in inferior cooking. Also, as the temperature detecting portion was adapted to be inserted or removed, the temperature detecting probe 5 was deformed or broken by mistake, thus preventing the correct temperature detection from be performed. As a result, the superior cooking result could not be provided, with the temperature being abnormally raised.

Also, the conventionally known electric oven was adapted to do the oven cooking through the upper, lower heaters, and the temperature detecting portion was also mounted inside to provide the higher safety. However, the pan cooking could not be done over the electric oven, which was extremely restricted in the use.

Summary of the Invention Accordingly, the present invention has been developed with a view to substantially eliminating the above discussed drawbacks inherent in the prior art. An essential object of the present invention is to provide an improved cooker, which is capable of doing the cooking widely from the oven cooking to the pan cookings by one unit.

Another object of the present invention is to provide a cooker which is capable of doing the excellent cooking through the uniform temperature at a constant temperature during the oven cooking.

A further object of the present invention is to provide the improved cooker, which is capable of doing the delicious cooking in accordance with the cooking conditions under the positive temperature control during the pan cooking.

Still a further object of the present invention is to provide the improved cooker, which is further higher in safety.

In accomplishing these and other objects, a rack to be detachably mounted on the container is provided, a container is pan-shaped, a temperature controlling apparatus is disposed on the bottom portion of the container, and there provides a further means which energizes and controls the upper heater provided in the upper portion within the cover for covering the upper opening portion of the container, and the lower heater provided in the lower portion of the container.

According to the above-described construction, the constant temperature is retained by the temperature disposed on the bottom portion of the container through the simultaneous energization to the upper heater, the lower heater during the oven cooking, the cooking operation free from failures is performed with proper balance, less uneven-roast.

Also, the temperature controller disposed on the bottom portion of the container detects the temperature of the pan with superior sensitivity by the cooking through the energization only to the lower heater during the pan cooking, so that the positive temperature control may be performed. As a result, the cooked which may cause a fire during the oil cooking may be safely done.

BriefDescription ofthe Drawings These and other objects and features of the present invention will become apparent from the following description taken in conjunction with the preferred embodiment thereof with reference to the accompanying drawings, in which: Fig. 1 through Fig. 4 show a longitudinal section view showing the various kinds of cooking condition of an electric cooker in one embodiment of the present invention; Fig. 5 is an inclined view of a rack to be used for the electric cooker; Fig. 7 is a circuit diagram for the electric cooker; and Fig. 8 is a longitudinal section view showing the conventional electric cooker.

Detailed Description of the Invention Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout the accompanying drawings.

Referring now to the drawings, there is shown in Fig. 1 through Fig. 6 an electric cooker according to one preferred embodiment of the present invention, which includes a pan-shaped container 9 having an opening portion disposed upwardly, the container 9 is made of a material, such as aluminum or the like, superior in heat conduction, and has a lower heater A10, a lower heater B11 cast simultaneously and mounted. The temperature controlling apparatus 12 which is disposed on the bottom portion of the container 9 is adapted to variably control the temperature of the container 9. A cooker main body 13 is engaged with the outer peripheral groove portion 14 of the container 9 to cover the side face of the container 9.The cooker main body has a pair of handles 15, 15a for carrying use, has a peg-frame 16 provided under one handle 15 to feed the power, has an operation panel 17 provided in the portion where the pair of handles 15, 15a are not provided.

A timer 18 of about sixty minutes and a change-over switch 19 for switching the heater are mounted through a switch mounting plate 20 on the operation panel 17. The mounting plate 20 is provided to cover the timer 18, the change-over switch 19to preventthe radiation heat from the container 9, heaters A10, B11 from hitting these functional components. The timer 18, the changeover switch 19 have knobs 21 respectively. A lever 22 is provided to vary the operation temperature of the temperature controlling apparatus 12.One end of the level 22 is pivotally supported by a step screw 24 on the heat insulating plate 23 mounted downwardly of the container 9, and the other end is projected out of the cooker main body 13 through the lower hole portion 25 of the operation panel 17 so that the operation may be effected from outside.

In the intermediate portion of the lever 22, the temperature variable pin 26 of the temperature controlling apparatus 12 is adapted to be pivoted so that the operation temperature may be freely set.

One end of the temperature fuse 27 is mounted on the terminal of the temperature controlling apparatus 12, the other end is mounted on the terminal pottery 28. A rear plate 29 is fixed to the heat insulating plate 23 by a mounting metal fitting 30 to depress the upward opening end of the cooker main body 13 against the other peripheral groove portion 14 of the container 9 to perform the fixing operation, the rear plate is adapted to cover the lower opening portion of the cooker main body 13.

The legs 31 are mounted with rivets on the reverse plate 29.

A cover 32 is adapted to cover the upward opening portion of the container 9 and to be displacable. The outermost diameter of the cover 32 is made a little smaller than the flange portion 33 of the container 9 so that the positioning operation is adapted to be effected properly. And a glass window 34 made of tempered glass is disposed in the ceiling center of the cover 32. One of the covers 32 is depressed by the support stand 36 mounted to cover the air port 35 of the cover 32 and the other thereof is fixedly depressed by one portion of the cover handle 37 of the cover 32. The glass window 34 is fixedly depressed through the ring-shaped packing 32b into the flange hole portion 32a of the cover by one portion of the cover handle 37 and one portion of the support stand 36 covering the air hole 35.This construction may positively prevent the smoke and the vapour from being leaked from the periphery of the glass window 34, the conduction heat from the cover 32 from being directly transmitted into the glass window 34 so that the temperature of the glass window 34 is prevented from being higher, the temperature of the cover handle 37, of the support portion of the glass window 34 of the support stand 36 is prevented from being higher. The terminal portion 39 of the upper heater 38 disposed upwardly of the interior of the cover 32 extends through the heater pottery 40 made of porcelain and is fixedly screwed with a heater connector 41. A heater support plate 42 which is mounted on the heater pottery 40 secures the upper heater 38 and has a pawl 43 provided in its top end.A reflection plate 44 has a suspension metal fitting 45 provided to support the upper heater 38, and a support pottery 46 made of porcelain which is superior in insulation is mounted on the periphery portion. Also, the reflection plate 44 is detachably engaged with the pawl portion 43 of the heater support plate 42 to insert the support pottery 46 into the support metal fitting 47 provided in the vicinity of the air port 35 of the cover 32 and to depress in the outer peripheral direction of the cover 32 the clip pivotally provided on the heater pottery 40, so that the upper heater 38 together with the reflection plate 44 is adapted to be detachably mounted on the cover 32. A perforated portion 44a is formed in the central portion of the reflection plate 44 to correspond with the glass window 34.

When the diameter of the perforated portion 44a is made smaller than the inner diameter of the packing 32b, the direct radiation heat to the packing 32b is avoided, so that the temperature of the packing 32b may be prevented from being raised. Also, the reflection plate 44 hangs up the upper heater 38 with the suspension 45, engages it with the pawl portion 43 of the heater support plate 42 to detachably mount the upper heater 38. And also the upper heater 38 and the reflection plate 44 depresses against the insertion opening 32c the clip 48 pivotally provided on the heater pottery 40 th rough the insertion of the heater pottery 40 into the heater insertion opening 32c of the cover 32 and through catching the support pottery 46 with the support metallic fitting of the cover 32 so that they are positively supported detachably.As the heater insertion opening 32c is adapted to be projected towards the inner side of the cover 32, the water drops are prevented from being moved into the terminal of the upper heater 38 if the vapor is dewed and the water drops are adhered within the cover 32, with the result that the insulation is positively prevented from being deteriorated. Furthermore, the water drops may be prevented from flowing outwardly from the heater insertion opening 32c.

One end of a coupling code 49 is inserted into the heater connector 41 of the upper heater 38 with a plug 50 for appliance use normally employed, and the other end is inserted into the peg frame 16 with a magnet plug 51 superior in safety. A power supply code 52 is detachably mounted by the plug for appliance use on the peg frame. A rack 54 made of stainless wire is used during the oven cooking or steam cooking. The rack 54 is composed of a portion 55 for receiving the cooked and a support time 56.

The portion 55 supports near the bottom face of the container 9, and the support portion 56 bends one portion thereof upwardly to form the handle portion 57. Further, the support portion 56 is placed on the step portion 9a of the opening upper portion of the container 9 which is lowered by one stage from the placement portion of the cover 32, and is positioned, supported without play. A steam cover 58 which is used in steam cooking or the like is composed of a material superior in corrosion resistance such as stainless or the like, has the handle 59 for steam cover provided in the central portion, which is placed within the flange portion 33 of the container 9.

A spring 60 provided with elastic force is located near the opening portion 25 of an operation panel 17 mounted on the cooker main body 13 and the operation panel 17 is mounted with rivets on the lever 22 so that it may be grasped with the lever 22.

Furthermore, an adjusting knob 61 is mounted on the other end of the lever 22. The upper portion projection 62 expands the spring 60 to feed the urging force with respect to the pivot of the lever 22.

When the adjusting knob 61 is set in a desired position in the above-described construction, the lever 22 pivots and a temperature adjuster 63 so that the operation temperature of the temperature controlling apparatus 12 is set into a necessary one.

As the lever 22 is properly given the urging force with respect to the pivot by the spring 60, the predetermined temperature is made extremely easierto be set. Also, the lever 22 is not moved by the vibrations or impacts, thus preventing the error operations. Also, to control the urging force, only the positional relation between the spring 60 and the lever 22 is required to be controlled, so that the dispersion is smaller.Also, in the assembling operation of the lever 22, insert one end of the lever 22 from the opening portion 25 to bring the spring 60 to come into contact against the operation panel 17 mounted on the opening portion 25, and insert the adjusting knob 61 into the other end of the lever 22 after one end of the lever 22 has been pivotally supported on the heat insulating plate 23 by the step screw 24, and the upper portion projection 62 of the adjusting knob 61 widens the space between the spring 60 and the lever 22 through the operation panel 17 to cause the urging force, with the result that the assembling operation of the lever 22 is made extremely easier and the deformation of the lever 22 itself caused by the assembling operation may be prevented.Furthermore, as the lever 22 is supported in the vicinity of the adjusting knob 61, the play of the adjusting knob is removed so that higher quality is provided. After the temperature has been positively set in this way, the oily cooked is put, the timer 18 is set and the container 9 is heated so that the safe, proper cooking may be performed with the constant temperature being retained.

In the above-described embodiment, one portion of the operation panel 17 is grasped by the lever 22 and the spring 60, but the flange-shaped opening portion may be formed integrally with the cooker main body 13 without restriction to this description, the modifications may be properly made without departing from the scope.

The electric circuit of the present embodiment will be described hereinafter. In Fig. 7, a timer 18 is connected with the power supply terminal Ll,one end of the lower heater A10 is connected in series, the movable contact 19a of the change-over switch 19 is connected. Also, one end of the lower heater B11 is connected with the stationary contact 19c, the other end, together with the other end of the lower heater A10, is connected with the temperature controller 12. On the other hand, the stationary contact 19b is connected with one end ofthe upper heater 38 through the movable contact 19d. And the other end of the upper heater 38 is connected with the movable contact 19f through the movable contact 19e.The stationary contact 19h, together with the other ends of the lower heater A10 and the lower heater By 1, is connected with one end of the temperature controlling apparatus 12 and the other end of the temperature controlling apparatus 12 is connected with the power supply terminal L2 through a temperature fuse 27. Also, the stationary contact 19g is directly connected with the powersupply terminal L2 through by-passing the temperature controlling apparatus 12, the temperature fuse 27. An energization display lamp 64 displays the energization condition.

The operation in the construction of the abovedescribed embodiment will be described hereinafter.

When the oven cooking for cake, roast chicken the cover with the upper heater 38 mounted thereon is placed on the container 9, an appliance 53 for the coupling code 49 is inserted into the heater connector 41 and the magnet plug 51 is inserted into the peg frame 16. When the change-over switch 19 is set in the position of the oven, the movable contact 19a is connected with the stationary contact 19b and the movable contact 19d is closed.

Furthermore, the movable contact 19e is closed and the movable contact 19f is connected with the stationary contact 19h. Then, set the lever 22 into the predetermined position and the operation temperature of the temperature controlling apparatus 12 is set to the temperature which is required to correspond with the required temperature.

Set the timer 18 to the necessary time and the power supply becomes on to simultaneously energize the lower heater Al 0 and the upper heater 38 to heat the interior. At this time, the temperature controlling apparatus 12 senses the temperature of the container 9. As the container 9 is pan-shaped and is formed integral in the entire under face, the heat receiving effect is superior, the correlation with respect to the interior temperature is extremely high so that the desired temperature may be positively set. After about ten minutes, pre-heating operation, the cover 32 is opened, the cooked such as cake is placed on the rack 54, the rack support portion 56 is placed on the step portion 9a of the opening upper portion of the container 9 with the handle portion 57 of the rack 54 as shown in Fig. 1 or Fig. 2, again the cover 32 is placed. Furthermore, set the timer 18 to the given time and the uniform heating operation is effected by the lower heater A10 and the upper heater 38, the optimum temperature is retained by the temperature re-controlling apparatus 12. The cooking condition may be confirmed by the glass window of the ceiling face of the cover 32 during the cooking operation. In this case, the lower heater A10 heats the cooked through the container 9, the caloric force becomes weak.But as the cooked is located near the bottom face of the container 9, the balance of the caloric power is improved, with the result that uneven roasting operation is reduced to ensure the superior cooking. Furthermore, as the portion 55 for receiving the cooked is lowered down to near the bottom face of the container 9, the effective cooking volume becomes larger, so that the grilling operation of one bird is sufficiently effected. Also, when the rack 54 is placed in the container 9, there is no risk of injuring the cooking face of the container 9. After the lapse of the given time, the timer 18 automatically turns off the power supply to complete the cooking operation. After the cooking operation, the cooked is taken out of the container by the handle 57 of the rack 54.

When the preparation such as fish broiling, bird grilling, pork roasting is performed with strong-fire heating, the support portion 56 of the rack 54 is placed on the step portion 9a of the opening upper portion for the positioning operation as in the former case with the rack 54 being reversed in top and bottom as shown in Fig. 3 and the portion 55 for receiving the cooked approaches the upper heater 38. When the change-over switch 19 is switched to the grill, the movable contact 19f only is switchingly connected with the stationary contact 199 with the movable contacts 19a, 19d, 19e being the same in position as the oven, so that only the upper heater 38 becomes irrelevant to the temperature controlling apparatus 12, thus resulting in continuously energizable condition.When the timer 18 is set to the position of the given time, the upper heater 38 and the lower heater A10 are simultaneously energized to quickly heat the interior. When the given temperature is reached, the temperature controlling apparatus 12 is operated to control the energization of the lower heater A10 to retain the container 9 at the constant temperature to prevent the container 9 from being raised to the abnormal temperature. Also, the upper heater 38 is continuously energized and the surface temperature of the heater becomes red in temperature at about 650"C and becomes stable. The upper heat 38 is continuously energized like this, the strong-fire heating operation is performed to cause a considerable amount of radiation heat so that the superior grill cooking is performed.In this case, the fish broiling, bird grilling, pork roasting or the like is heated with the caloric operation through the powerful upper heater 38 so that the delicious cooking may be performed with the surface being somewhat scorched. The required heater output of the upper heater 38 is approximately 500 W according to the experiment. Accordingly, the cover 32, the cover handle 37 and soon are not thermally deformed, thus resulting in the operation. Also, the current flowing to the temperature controlling is reduced in amount so that the risk of depositing the electric contacts is almost removed. Also, the cooking condition may be confirmed through the glass window 34 on the ceiling face of the cover 32 during the cooking operation. The oily smoke, vapor or the like is produced during the operation of the cooked.They are adapted to flow out of the cooker through the air hole 35 of the cover 32. After the lapse of the given time, the timer 18 switches off the power supply to preventthe excessive roasting operation to notify the user of it.

An oven cooking for requiring the temperature precision, a grill cooking for requiring the strong-fire heating and mainly using the radiation heat may be set only by the operation of the change-over switch 19, so that the apparatus which is lower in price and superior in operation may be provided.

Also, in order to do the steam cooking by the use of the steam cover 58 with the lower heaters AlO, B1 1 only without the use of the upper heater 38, a proper amount of water is put into the container 9 as shown in Fig. 4, the rack 54 is set as described hereinabove, the steam cover 58 is placed, so that the steam cooking operation may be performed, thus causing extremely large use value.

In the above-described embodiment, the rack was constructed through the stainless-wire working operation, while the rack 54 may be composed of plate and a hole portion may be provided in the plate, the modifications may be properly performed within the scope without being departed from the summary.

Furthermore, when the pan cooking is performed, the cover 32 is removed with the coupling cord 52 being not connected. Also, the rack 54 is also disengaged from the container 9. When the changeover switch 19 is provided in the position of the Chinese pan, the movable contact 19a is connected with the stationary contact 19c, the movable contact 19d is made open, furthermore the movable contact 19e is rendered also open. Thus, the upper heater 38 is both cut to become off, the lower heater A10 and the lower heater B1 1 become simultaneously energizable in condition. When the cooking is performed with the use of the fry oil, the lever 22 is set in advance in the given position so that the optimum oil temperature is adapted to be provided.

When the timer 18 is set to the continuous ON or the position of the given time, the lower heater A10 and the lower heater B1 1 are simultaneously energized to heat the container more, and the temperature controlling apparatus 12 is operated when the given temperature is reached to retain the constant temperature. As the temperature controlling apparatus 12 directly detects the temperature of the container 9 at this time, the sensitivity becomes better, so that the error operation is hardly caused.

Also, in the oven cooking and the grill, the upward radiation heat of the upper heat 38 is reflected by the reflection plate 44 provided to cover the heating portion of the upper heater 38 and is radiated on the side of the cooked to efficiently perform the cooking.

Also, as the radiation heat is not directly applied upon the cover 32, the glass window at this time, the abnormal temperature rise is avoided and the radiation is reduced. Also, as the interior may be easily observed from the glass window 34 of the ceiling face during the cooking operation, there is no possibility that the delicate degree of the fire is provided by mistake to scorch the cooked. The interior temperature normally becomes higher in the central portion because of the less radiation. But the uniform temperature distribution is provided as the radiation is radiated to the proper degree by the perforated portion 44a of the reflection plate 44, and the glass window 34, with the result that the cooking less in uneven roasting operation may be performed. Also, as the inner diameter of the perforated portion 44a of the reflection plate 44 is made smaller than the diameter of the packing 32b sealing the glass window 34, the temperature rise of the packing 32b may be reduced, because the radiation heat or the heat rays which flow upwardly through the perforated portion 44a are not directly applied upon the packing 32b.

Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be noted here that various changes and modications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as included therein.

Claims (8)

1. An electric cooker comprising a cooker main body, a pan-shaped container provided within the cooker main body and having an opening portion provided in the upper portion thereof, a cover for covering the upper opening portion of the container, a lower heater provided in the lower portion of said container, an upper heater provided in the upper portion within said cover, a rack mounted detachably within said container, a temperature controlling apparatus disposed on the bottom portion of the container and means for controlling at least one of the heaters.

2. An electric cooker in accordance with claim 1, wherein a circuit is provided to simultaneously control in temperature the upper and lower heaters.

3. An electric cooker in accordance with claim 1, wherein only the lower heater is controlled in temperature by the temperature controlling apparatus, the upper heater is arranged to be continuously energised in use.

4. An electric cooker in accordance with claim 1, wherein a circuit for simultaneously controlling in temperature the upper and lower heaters and a circuit for controlling in temperature the lower heater only are switchably selectable.

5. An electric cooker described in accordance with any foregoing claim, wherein the cooker main body comprises an adjusting knob for variably operating the operation temperature of the temperature controlling apparatus from the outside of the cooker main body and a spring-biassed lever for coupling a temperature adjustor of said temperature controlling apparatus to the adjusting knob.

6. An electric cooker in accordance with any foregoing claim, wherein the support portion of the rack is supported on the peripheral edge of the opening portion of the upper of the container.

7. An electric cooker in accordance with any foregoing claim, wherein a cover has a window provided in the central portion of the ceiling face, a reflection plate is disposed between the upper heater and the cover, the reflection plate covers the whole heating portion of said upper heater and is provided in the central portion with a perforated portion which is substantially the same size as said window.

8. An electric cooker in accordance with claim 7, wherein the window is secured to the cover by way of packing, the perforated portion of the reflection plate being smaller than the aperture of packing.