JPS6312211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooking device such as a grill that heats and browns an object to be cooked.

Traditionally, cookers that have both the function of a microwave oven that performs high-frequency dielectric heating and the function of a grill that browns the food have been equipped with a heater that browns the food in the heating chamber. During high-frequency dielectric heating, the heater is displaced upward away from the food placed in the heating chamber, and when browning, the heater is lowered within the heating chamber, and the heater is moved upward away from the food placed in the heating chamber. Close to each other. In such cooking devices, when browning the food, there is a tendency to forget to move the heater downward so as to bring it closer to the food. In particular, when browning the food less frequently than cooking using high-frequency dielectric heating, it is easy to forget to move the heater close to the food to brown the food.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cooking device that allows the user to operate the heater without making mistakes when browning the food to be cooked.

In the present invention, a heater for radiant heating of the food to be cooked, which is placed in the lower part of the heating chamber, is provided so as to be able to approach and move away from the food in the vertical direction, and the heater is placed at a position away from the food to be cooked. A temperature detection element is disposed close to the top of the heating chamber, and an erroneous operation detection means is provided for detecting, based on the output of the temperature detection element, that power is energized to the heater located at a position away from the food to be cooked. This cooking device is characterized by:

FIG. 1 is a simplified vertical sectional view of a cooking device 1 according to an embodiment of the present invention. A turntable 4 is provided horizontally at the bottom of a heating chamber 3 formed within the cabinet 2. This turntable 4
is rotationally driven around a vertical axis by a motor 5. A food to be cooked 7 is placed on the turntable 4. Inside the heating chamber 3, electromagnetic waves are generated by a magnetron 6. This electromagnetic wave causes high-frequency dielectric heating of the food to be cooked. At this time, the turntable 4 rotates, and the food to be cooked 7 is heated evenly.

A heater 8 is provided in the heating chamber 3. The heater 8 is movable toward and away from the food 7 to be cooked. In this embodiment, the heater 8 is raised away from the food 7 as shown by the solid line, and is lowered close to the food 7 as shown by the phantom line 9. The vertical position can be adjusted manually. Heater 8 is imaginary line 9
By bringing the food to the position shown in and energizing it with electric power in a state close to the food to be cooked 7, the food to be cooked 7 is radiantly heated and browned marks are formed.

A thermistor 10 as a temperature detection element is arranged on the ceiling 31 of the heating chamber 3. This thermistor 10 is configured such that the heater 8 is separated from the food to be cooked 7 and the first
It is close to the heater 8 at the position indicated by the solid line in the figure. A fan 11 is provided to exhaust smoke, water vapor, etc. inside the heating chamber 3 to the outside.

FIG. 2 is an electrical circuit diagram related to the magnetron 6, heater 8, and thermistor 10. When the door for opening and closing the heating chamber 3 is closed, the switch 12 becomes conductive. When performing high-frequency dielectric heating, the common contact 14 of the changeover switch 13 is switched to the individual contact 15 for conduction. When browning is performed by radiant heating using a heater, the common contact 14 of the changeover switch 13 is electrically connected to another individual contact 16. A high voltage generating circuit 17 for applying a high voltage to the magnetron 6 is provided between the door switch 12 and the changeover switch 13.
A timer switch 19 of a timer 18 is connected in series to the changeover switch 13.

By making the common contact 14 of the changeover switch 13 conductive to the individual contact 15 and setting the timer 18, the timer switch 19 is made conductive for a predetermined time.
High frequency dielectric heating is performed by generating electromagnetic waves for a set time.

A resistor 20 is connected in series to the thermistor 10. A connection point 29 between the thermistor 10 and the resistor 20 is applied to one input of the comparator 21. The other input of the comparator 21 has resistors 22, 2
The voltage at the node 30 set by 3 is given. The thermistor 10 has a characteristic that when heated, the resistance at both ends of the thermistor 10 decreases. Comparator 21
When the temperature detected by the thermistor 10 exceeds, for example, 180° C. and the voltage at the node 29 becomes lower than the voltage at the node 30, a high level signal is derived to turn on the transistor 24. As the transistor 24 becomes conductive, the relay coil 26 of the relay 25 is excited, the relay switch 27 is cut off, and the buzzer 28 sounds. The relay switch 27 is connected in series with the heater 8,
It is interposed between the door switch 12 and the individual contact 16 of the changeover switch 13. Comparator 21, resistor 2
2, 23, transistor 24, relay 25, and buzzer 28 constitute erroneous operation detection means.

FIG. 3 shows the temperature of the thermistor 10 and the temperature of the heater 8.
The relationship between the upper and lower positions in the heating chamber 3 is shown. The heater 8 is located at an upper position P1 near the ceiling 31, as shown by the solid line in FIG. Rise. Further, when the heater 8 is lowered to the position P2 shown by the imaginary line 9 and brought close to the food to be cooked 7 in order to brown the food, the thermistor 10 is
The temperature can only be raised to 100℃. Therefore, it can be seen that the vertical position of the electrically energized heater 8 in the heating chamber 3 corresponds to the temperature detected by the thermistor 10.

FIG. 4 is a graph showing the temperature of the thermistor 10 when the position of the heater 8 is changed.
When the heater 8 is displaced upward as shown by the solid line in FIG. 1, when the heater 8 is energized at time t1, the temperature of the thermistor 10 rises rapidly as shown by the curve l1. Further, when the heater 8 is lowered and set at the position shown by the imaginary line 9, when the heater 8 is energized at time t1,
As shown by curve 12, the rate of temperature increase is slow.

When the heater 8 is placed close to the food to be cooked 7 as shown by the imaginary line 9 and the common contact 14 of the changeover switch 13 is electrically connected to the individual contact 16, the door switch 12 and the timer switch 1 of the timer 18 are connected.
9 is turned on, the heater 8 is heated, and the food to be cooked 7 is browned. In this case, as is clear from FIGS. 3 and 4, the thermistor 10 is heated only to about 100° C. at most. Therefore, the output of the comparator 21 remains at low level, and the output of the transistor 24
is cut off, and the relay switch 27 remains conductive.

Assume that when browning the food 7, the heater 8 is erroneously energized while being displaced upward as shown by the solid line in FIG. In this case, the temperature of the thermistor 10 suddenly becomes high in a short period of time, as shown by curve l1 in FIG. Therefore, the output of the comparator 21 becomes high level in a short time after the power is applied to the heater 8, and the transistor 24 becomes conductive. Therefore, the relay coil 26 of the relay 25 is energized, and the relay switch 27 is activated.
is blocked. In this way, the heater 8 is deenergized and the buzzer 28 sounds.

As described above, according to the present invention, the heater for radiant heating of the to-be-cooked food placed in the lower part of the heating chamber is provided so as to be movable and separated in the vertical direction with respect to the to-be-cooked food, and the temperature detection element is configured to heat the food. The erroneous operation detection means is disposed in the upper part of the room close to the heater located at a position away from the food to be cooked, and the erroneous operation detection means applies power to the heater located at a position away from the food to be cooked based on the output of the temperature detection element. Since energization is detected, it is now possible to generate an alarm based on this erroneous operation detection, and also to prevent unnecessary energization by canceling power energization to the heater. . Therefore, when browning the food, it is possible to reliably keep the heater close to the food.

[Brief explanation of the drawing]

FIG. 1 is a simplified vertical sectional view of a cooking device 1 according to an embodiment of the present invention, FIG. 2 is an electric circuit diagram related to the magnetron 6, heater 8, and thermistor 10 shown in FIG. 1, and FIG. The figure and Figure 4 show the heater 8.
3 is a graph showing the temperature of the thermistor 10 corresponding to the upper and lower positions in the heating chamber 3 of FIG. 1...Cooker, 3...Heating chamber, 6...Magnetron, 7...To be cooked, 8...Heater, 10...
Thermistor, 21... comparator, 25... relay.

Claims (1)

[Scope of Claims] 1. A heater for radiant heating of the object to be cooked, which is placed in the lower part of the heating chamber, is provided so as to be able to approach and move away from the object in the vertical direction, and is located at a position away from the object to be cooked. An erroneous operation in which a temperature detection element is placed in the upper part of the heating chamber in close proximity to a certain heater, and based on the output of the temperature detection element, it is detected that power is applied to a heater located away from the food to be cooked. A cooking device characterized by being equipped with a detection means.