JPH1189731A - Oven toaster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toaster excellent in automatic heating and inexpensive by turning on electricity to a heater until voltage of both terminals of a capacitor charged by a generally regular electric current reaches standard voltage of a partial voltage by resistance and heat sensitizing element. SOLUTION: When a start switch 23 is pushed a PNP transistor 25 is on, and a contact 27 is operated by a relay 26 to turn on electricity between an upper heater 1 and a lower heater 2. At the same time an electric charge of a capacitor 6 is discharged, voltage B between the both terminals of the capacitor 6 becomes zero, and the PNP transistor 25 remains on condition. After this, the capacitor 6 is charged by a regular current, the voltage B increases at a regular gradient together with time elapsed. When the voltage A, out put of a comparator 24 becomes high, the PNP transistor 25 turns off, the contact 27 is recovered by the relay 26, and the upper heater 1 and the lower heater 2 turns off. Hereby, heating time period is automatically determined and the resistance is only modified, the heating time period is optionally modified to optimalize the automatic heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oven toaster used in ordinary households.

[0002]

2. Description of the Related Art In recent years, oven toasters have been used for home use and the like. For example, there is one having a simple electric circuit shown in FIG.

The time switch 3 turns on when the heating time is set according to the rotation angle of the knob, the upper heater 1 and the lower heater 2 are turned on, and when the knob returns to a predetermined position by the return force of the mainspring, the time switch 3 is turned on. Is turned off, and the upper heater 1 and the lower heater 2 are turned off. With such a configuration, heating is performed by arbitrarily adjusting the heating time according to the cooking material.

[0004]

As for the automatic heating of bread, although cooking is performed with high precision by controlling a microcomputer or the like, it is expensive. Some were inexpensive and had a timer, but the accuracy was not good. Therefore,
There is no inexpensive oven toaster with high accuracy of automatic heating, and an oven toaster having such a function has been desired.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides a reference voltage for dividing a voltage by a resistor and a temperature sensing element and a voltage across a capacitor charged by a substantially constant current. And a heating means for energizing the heater until the temperature of the oven toaster is reached.

[0006] With the above configuration, it is possible to realize an inexpensive oven toaster that performs automatic heating of bread with high accuracy.

[0007]

DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present invention, a reference voltage of a voltage divided by a resistor and a temperature sensing element and a voltage across a capacitor charged by a substantially constant current reach the reference voltage. The heater is an oven toaster having a heating means for energizing the heater until the reference voltage can be set in accordance with the configuration of the main body with a single resistor, so that automatic heating can be performed accurately with continuous heating.

According to a second aspect of the present invention, there is provided a method of controlling a heater until a voltage between both ends of a capacitor charged by a substantially constant current and a reference voltage of a divided voltage by a resistor and a temperature sensing element reach the reference voltage. The oven toaster is provided with a heating means for supplying current and a switch for switching the substantially constant charging current. The automatic heating time is adjusted by a switch for switching the charging current, and the burning color can be switched and set.

According to a third aspect of the present invention, a reference voltage for dividing a voltage by a resistor and a temperature sensing element and a voltage applied to a heater until a voltage across a capacitor charged by a substantially constant current reaches the reference voltage are reached. An oven toaster equipped with a heating unit that conducts electricity and a volume device that can adjust the substantially constant charging current, and by adjusting the volume device, it is possible to adjust the automatic heating time and arbitrarily set the baking color. it can.

According to a fourth aspect of the present invention, there is provided the oven toaster according to any one of the first to third aspects, further comprising a buzzer notification device for notifying the baking of the bread. I can let you know.

[0011]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 1 is a circuit configuration diagram of the present embodiment, and FIG. 2 is a specific electric circuit diagram. The same components as those in the above-mentioned conventional example are denoted by the same reference numerals and described.

First, the upper heater 1 and the lower heater 2 are heaters for heating the inside of the oven toaster storage. Half-wave rectification is performed by the resistor 11 and the diode 12, and the voltage is made constant by the zener diode 13 and the capacitor 14. Temperature sensing element 4
(Thermistor), resistor 15 and resistor 3
Non-inverting amplification (13 times in this embodiment) is performed by the operational amplifier 18 to obtain a reference voltage A. This reference voltage A is shown in FIG.
As shown in (2), the resistance value of the temperature-sensitive element 4 during heating decreases as the temperature rises, and such a voltage curve is drawn. FIG. 3 shows a voltage change diagram input to the comparator 24 of the oven toaster. Further, the light emitting diode 19, the resistor 20, the PNP transistor 21, and the resistor 22 constitute a constant current circuit.
A]. The voltage B across the capacitor 6 is B in FIG.
A voltage curve having a constant gradient is drawn as time passes as shown in FIG.

Next, the operation will be described. When the start switch 23 is pressed, the PNP transistor 25 is turned on, the contact 27 is operated by the relay 26, and the upper heater 1 and the lower heater 2 are energized. At the same time, the charge of the capacitor 6 is discharged, and the voltage B across the capacitor 6 becomes zero.
[V], and the PNP transistor 25 is kept on. Thereafter, the capacitor 6 is charged with a constant current, and the voltage B rises with a constant gradient as time passes. Voltage B
Becomes higher than the reference voltage A (point A in FIG. 3), the output of the comparator 24 becomes High, the PNP transistor 25 is turned off, the contact 27 is restored by the relay 26, and the upper heater 1 and the lower heater 2 are turned off. I do.

FIG. 4 is a graph showing a heating time in which the baking color of the bread is kept constant according to a difference in the cooking start temperature, that is, an ideal heating characteristic diagram of the oven toaster.

FIG. 5 is a diagram showing a change in the voltage input to the comparator 24 obtained by the calculation of the oven toaster. That is, when the reference voltage A of the present embodiment is graphed when the temperature of the thermistor at the start is 20, 60, and 120 [° C.], the graph becomes as shown in FIG. 5, and the intersection with the voltage B of the capacitor 6 is Time is 92, 108, 1
30 [sec]. When this is graphed, it becomes as shown in FIG. 6E, and a heating characteristic close to the ideal curve (shown by a broken line in FIG. 6) of FIG. 4 can be obtained with a relatively simple configuration. Further, the heating time can be arbitrarily changed only by changing the resistance value of the resistor 20 in the circuit diagram 2, and accurate automatic heating can be performed.

In the first embodiment, the circuit configuration of the constant current source uses a light emitting diode and a PNP transistor. However, a configuration such as a current mirror circuit or the like may be used.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a specific electric circuit diagram of the present embodiment, and FIG. 8 is a diagram of a voltage change input to the comparator 24 obtained by the calculation of the oven toaster. The same components as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted.

By the changeover switch 29, the charging current to the capacitor 6 is determined by the resistor 20 or the resistor 28. Here, the resistance of the resistor 2 is calculated based on the resistance value of the resistor 20.
If the resistance value of 8 is larger, the current of the resistor 28 is smaller. The reference voltage A has a temperature of 60 at the start.
In the case of [° C.], the straight line of A in FIG. 8 is drawn. In addition, resistor 2
When 0 is selected, the curve of B1 is selected when the resistor 28 is selected.
Draw the curve of B2. Here, each intersection becomes a point F and a time becomes 100 and 120 [sec]. Therefore, the heating time can be switched to 100 seconds or 120 seconds, and as a result, the baking color of the bread can be switched.

As described above, the roasting color of bread can be switched with a relatively simple configuration.

In the second embodiment, the number of changeover switches is two. However, a plurality of changeover switches may be used.

(Embodiment 3) Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a specific electric circuit diagram of the present embodiment. The same components as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted. By adjusting the variable resistor 30, the current for charging the capacitor 6 can be varied. Here, when the variable resistor 30 is varied, a curve B in FIG. 10 is drawn according to the resistance value of the variable resistor 30. The reference voltage A draws a straight line at a temperature at the start of 60 [° C.]. here,
The intersections are J, L, and N, and the time is 100, 1
10, 120 [sec]. Therefore, the heating time is 1
It can be changed from 00 seconds to 120 seconds, and as a result, the baked color of the bread can be arbitrarily changed.

(Embodiment 4) Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 11 is a circuit configuration diagram of the present embodiment. The same components as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted. When the switch 7 is pressed, the heating control means 9 supplies power to the upper heater 1 and the lower heater 2. When the automatic heating is completed, the upper heater 1 and the lower heater 2 are turned off by the heating control means 9 and a buzzer is notified by the buzzer notifying means 31 to inform the user of the completion of the bread.

As described above, the buzzer informs the user that cooking has been completed by the automatic heating, so that the user can know that cooking has been completed even if the user is away.

[0024]

According to the first aspect of the present invention, the heater is energized until the reference voltage of the voltage divided by the resistor and the temperature sensing element and the voltage across the capacitor charged by the substantially constant current reach the reference voltage. , The heating time can be automatically set with a relatively simple configuration, and when changing the main body configuration, the heating time can be changed arbitrarily to optimize the automatic heating by simply changing the resistance. The effect that it can be obtained is obtained.

According to the second aspect of the present invention, the reference voltage of the voltage divided by the resistor and the temperature sensing element and the substantially constant current are switched to a predetermined current by the changeover switch, and the voltage across the capacitor charged by the current. By supplying power to the heater until the heater reaches the reference voltage, the heating time can be switched and set with a relatively simple configuration, and the baking color of the bread can be switched.

According to the third aspect of the present invention, the reference voltage of the voltage divided by the resistor and the temperature sensing element and the substantially constant current are set to a predetermined current by the volume device, and both ends of the capacitor charged by the current are set. By energizing the heater until the voltage reaches the reference voltage, the heating time can be automatically set with a relatively simple configuration, and the baking color of the bread can be set arbitrarily.

According to the fourth aspect of the present invention, the end of cooking is notified by a buzzer, so that the user can be notified of the end of cooking even if he is not nearby during cooking.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of an oven toaster according to a first embodiment of the present invention.

FIG. 2 is an electric circuit diagram of the oven toaster.

FIG. 3 is a diagram showing a change in voltage input to a comparator 24 of the oven toaster.

FIG. 4 is an ideal heating characteristic diagram of the oven toaster.

FIG. 5 is a diagram showing a change in a voltage input to a comparator 24 obtained by calculation of the oven toaster.

FIG. 6 is a heating characteristic diagram obtained by calculation of the oven toaster.

FIG. 7 is an electric circuit diagram of an oven toaster according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a change in voltage input to a comparator 24 obtained by calculation of the oven toaster.

FIG. 9 is an electric circuit diagram of an oven toaster according to a third embodiment of the present invention.

FIG. 10 is a diagram showing a change in voltage input to a comparator 24, which is obtained by calculation of the oven toaster.

FIG. 11 is a circuit configuration diagram of an oven toaster according to a fourth embodiment of the present invention.

FIG. 12 is an electric circuit diagram of a conventional oven toaster.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper heater 2 Lower heater 3 Resistor 4 Temperature sensing element 5 Constant current source 6 Capacitor 7 Switch 8 Comparison means 9 Heating control means 20 Resistor 24 Comparator 27 Contact 28 Resistor 29 Switch 30 Variable resistor 31 Buzzer notification means

Claims (4)

[Claims] An oven having a reference voltage of a voltage divided by a resistor and a temperature sensing element, and heating means for energizing a heater until a voltage across a capacitor charged by a substantially constant current reaches the reference voltage. Toaster. 2. A heating means for energizing a heater until a voltage across a capacitor charged by a substantially constant current reaches the reference voltage, the reference voltage being a voltage divided by a resistor and a temperature sensing element, and Oven toaster with a switch that can switch the charging current of the oven. 3. A heating means for energizing a heater until a voltage across a capacitor charged by a substantially constant current reaches the reference voltage, the reference voltage being a voltage divided by a resistor and a temperature sensing element, and Oven toaster equipped with a volume device that can adjust the charging current of the oven. 4. The oven toaster according to claim 1, further comprising a buzzer notification device for notifying the baking of the bread.