JPH0739461A - Heat cooker - Google Patents

Abstract

PURPOSE:To provide a toaster which is low-priced, convenience for use is improved by lessening the number of key switches on a console panel. CONSTITUTION:The heat cooker comprises a signal control part 21 for inverting the level of an output signal every time a signal is input, a cooking time setting part 24 including a timer circuit formed by a resistance and a capacitor and a thermistor for detecting the oven temperature, and in which the time period of the timer circuit is set according to the detected temperature of the thermistor when the output signal is 24 a high-level and a signal is output to the signal control part 21 after the lapse of preset time and a relay driving circuit 22 for energizing a heater 23 when the output signal is at a high-level and stopping energizing the heater 23 when the output signal is at a low-level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toaster, for example, and more particularly to a control circuit thereof.

[0002]

2. Description of the Related Art FIG. 4 is a perspective view showing the appearance of a toaster, FIG. 5 is an enlarged view of an operation panel, FIG. 6 is a block diagram for explaining the operation of the toaster, and FIG. 7 is a circuit diagram.

In the drawing, 1 is a main body, 2 is a door of a cooking cabinet in which a heater (not shown) is arranged, 3 is an operation panel, and as shown in FIG. 5, a toast key switch 4 for starting cooking is shown. , Indicator light 5 that lights up during cooking, L that displays time
CD6, cancel key switch 7 to stop cooking,
A slide knob 8 for adjusting the dark spots, a menu selection key switch 9 for selecting various menus, a group of indicator lights 10 for displaying the menu selected by the menu selection key switch 9, and a time setting knob 1 for setting the cooking time.
It consists of 1.

Next, the operation will be described with reference to the block diagram of FIG. When cooking toast, the toast key switch 4 is pressed after the bread is put in the cooking cabinet. in this case,
Microcomputer (hereinafter referred to as "microcomputer") 1
2 displays the preprogrammed cooking time on the LCD 6 and turns on the indicator lamp 5 and then controls the relay circuit 15 to heat the heater. Then, when the heating reaches the cooking time, the heater is turned off and the sounding unit 14 generates a buzzer sound. Further, when adjusting the browning with the slide knob 8 during toast cooking, the analog voltage setting potentiometer 13 outputs a potential according to the moving amount of the knob 8 to the microcomputer 12, so that the microcomputer 1
2 sets the cooking time corresponding to the input potential and sets it to L
The display is displayed on the CD 6 and the indicator lamp 5 is turned on, and then the relay circuit 15 is controlled to heat the heater. The cooking time in this case becomes shorter when the slide knob 8 is slid to the left, and becomes longer when the slide knob 8 is slid to the right. Further, the second and subsequent cooking times are set based on the elapsed time after the end of the previous cooking. The shorter the elapsed time, the shorter the cooking time.
This is because the heat remaining in the cooking chamber is used. For other cooking, select the required menu from the menu group with the menu selection key switch 9,
A predetermined time is set with the time setting knob 11, and then the toast key switch 4 is pressed.

[0005]

In the above-described conventional toaster, as shown in FIG. 7, the high precision constant voltage IC 17, the reset IC 18, the clock oscillator 19, the LCD 6 and the like, which are indispensable for the operation of the microcomputer 12, must be used. Therefore, the cost burden was large. In addition, L on the narrow operation panel 3
Since it is necessary to arrange the CD 6 and the cancel key switch 7 and the like, the size of the LCD 6 and the key switches 4, 7 and 9 are small, and it cannot be said that the usability is good.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a cheap toaster while reducing the number of key switches on the operation panel to improve usability.

[0007]

A heating cooker according to the present invention includes a signal control unit for inverting the level of an output signal each time a signal is input, a time circuit including a resistor and a capacitor, and an internal temperature. A thermistor for detecting, and when the output signal is at a high level, sets the time limit of the time limit circuit based on the temperature detected by the thermistor, and a cooking time setting unit that outputs a signal to the signal control unit after the set time elapses. A heating drive unit that heats the heating unit when the output signal is at a high level and stops heating of the heating unit when the output signal is at a low level. Further, the time constant of the time limit circuit is made variable according to the heating amount.

[0008]

In the present invention, when the first signal is input to the signal controller, the signal controller outputs a high level signal, and when the second signal is continuously input,
Inverts the output signal level to low and outputs. Therefore,
When one switch is connected to the input side of the signal control unit and pressed a plurality of times, the output signals are inverted in level from high to low and low to high. When the output signal is at a high level, the cooking time setting unit sets the time limit of the time limit circuit based on the temperature detected by the thermistor, and the heating drive unit heats the heating unit during the time limit. Further, since the time constant is changed according to the heating amount of the heating unit, the cooking time can be set according to the menu.

[0009]

1 is a block diagram for explaining one embodiment of the present invention, FIG. 2 is an enlarged view of an operation panel, and FIG. 3 is a circuit diagram for explaining the operation of the embodiment. Incidentally, the same or corresponding parts as those of the conventional example described in FIG.

In FIG. 1, reference numeral 20 denotes a cooking start switch, which is provided on the operation panel as shown in FIG. 2 and has an LED which is turned on at the start of cooking. A signal control unit 21 outputs a signal each time one pulse is input to control the relay drive unit 22 and the cooking time setting unit 24. The relay driver 22 operates when the signal is H and heats the heater 23. The cooking time setting unit 24 has a thermistor TH, sets the cooking time according to the temperature in the cooking cabinet when the signal is input, and after the lapse of time, the 3 second time limit unit 25 and the 4 KHz buzzer oscillating unit 26. Operate. 3 seconds time limit part 2
5 activates the 4 KHz buzzer oscillating unit 26 for 3 seconds to stop the control of the signal control unit 21. The 4 KHz buzzer oscillating unit 26 causes the buzzer to ring during that time.

Reference numeral 27 denotes an input switching unit which operates the set time switching unit 28 when a snack switch provided on the operation panel is pressed. The set time switching unit 28 requests the cooking time setting unit 24 to extend the cooking time. Two
Reference numeral 9 denotes a manual switching unit that stops the operation of the signal control unit 21 and drives the heater driving unit 22 when the manual timer 34 provided on the operation panel is set.

In FIG. 2, reference numeral 30 denotes a cooking start switch, which is provided with an LED that is turned on when cooking is started. Reference numeral 31 is a toast switch, and 32 is a snack switch. When the toast switch 31 is pressed, the upper and lower heaters (total heat power: 900 W) in the cooking cabinet are fully energized, and when the snack switch is pressed, the upper heater is half-wave energized. The lower heater is energized with full waves. At the time of use, either the toast switch 31 or the snack switch 32 is pushed in and locked. For example, when the cooking start switch 30 is momentarily pressed while the toast switch 31 is being pressed, the LED is turned on and the upper and lower heaters are energized. Further, even when the snack switch 32 is pushed in, the energization is similarly executed for a predetermined time.

Reference numeral 33 is a menu group printed on the glass of the door 2, and the corresponding menu is a standard printed on the glass of the door 2. An appropriate cooking time is set in the CR timer for these menus, and the time is properly selected and executed depending on the temperature situation and the temperature rise inside the cooking cabinet. Reference numeral 34 is a manual timer. When this timer is used, automatic cooking is prohibited as described above, and cooking is executed at the set time of the timer.

Next, the circuit of FIG. 3 will be described. In the figure, 21a is, for example, a toggle flip-flop circuit having the same function as the signal control unit 21 described in FIG. 1, and the signal level is inverted and output from the output Q every time a signal is input to the input Cp. Since the output Q is L at the time when 100 V AC is applied to the terminals X and Y, the relay driving transistor Q1 is off and the capacitor C
5 is short-circuited by the diode D5. When the cooking start switch is pressed while the toast switch 31 provided on the operation panel is pressed, the capacitor C4 starts discharging and the signal is input to the input Cp of the toggle flip-flop circuit. At this time, since the H signal is output from the output Q of the circuit 21a, the transistor Q1 is turned on, and the relay RY is operated accordingly and the contact is closed. At the same time, the LED provided on the cooking start switch is turned on to display that effect. At this time, since the snack switch 32 is closed, the upper and lower heaters are energized in full waves. As a result, the potential of the resistor R22 is sufficient to bring the transistor Q3 into conduction. Therefore, the transistor Q4 is blocked and the capacitor C6 is disconnected.

On the other hand, the capacitor C5 is started to be charged through the resistor R8 and the potential thereof gradually rises. Voltage comparator A
One input is set to a potential consisting of the thermistor TH and a series of resistors connected to it, and at the start of cooking, the input side of the voltage comparator A has the relationship of one input voltage> + input voltage, and therefore an L signal is output. ing. At this time, condenser C
Since 8 is short-circuited and the capacitor C9 is also short-circuited by the diode D7, the self-excited oscillation of the voltage comparator C is blocked. After that, condenser C
As the charging of 5 progresses, the input side of the voltage comparator A becomes + input voltage>
When there is a relation of one input voltage, the output thereof is inverted to H, and the self-excited oscillation of the voltage comparator C starts and the buzzer sounds. Next, the capacitor C8 is no longer short-circuited and the resistor R1
It is charged via 1. In the voltage comparator B, since + input voltage> one input voltage at first, the output is H, but when the charging potential of the capacitor C8 rises and one input voltage> + input voltage, the output becomes L. The oscillating circuit composed of the voltage comparator C at the next stage is inverted and stops operating. The time determined by the time constant of the capacitor C8 and the resistor R11 is 3 seconds, and as a result, the buzzer sounds for 3 seconds after the output of the voltage comparator A is inverted. The output of the voltage comparator B is the L signal, and the transistor Q2 is coupled to the capacitor C11 to operate for a moment, and the H signal is output from the collector of the transistor Q2 and applied to the input Cp of the toggle flip-flop circuit 21a. At this time, the output is inverted to L, so that a series of operations is completed. At the same time, the relays RY and LED are blocked and the operation ends.

The operation of the thermistor TH of the circuit of the voltage comparator A will be described. When the first cooking is finished, the resistance value of the thermistor TH decreases because the temperature inside the cooking cabinet has risen. As a result, one input voltage of the voltage comparator A decreases, and the time until inversion becomes short. This rate of change is Rp
Since the characteristics can be adjusted arbitrarily with Rd and Rc, it can be freely adjusted according to the preheating characteristics in the cooking cabinet. If the snack switch 32 is pressed on the operation panel, its contact 32a
Is opened and the upper heater is energized by a half wave, and the potential of the resistor R22 is lowered, and the transistor Q3 is blocked. At this time,
Since the transistor Q4 becomes conductive, the capacitor C6 is connected. As a result, the capacity of the capacitor combined with the resistor R8 becomes the total capacity of the capacitors C5 and C6,
The cooking time will increase as the condenser capacity increases. Generally, snacks are fried potatoes, and cooking time is about twice as long as toast. When the manual timer 34 of the operation panel is operated, the timer contact 34a is closed and the relay RY operates, but at the same time, the input Cp of the toggle flip-flop circuit 21a is forced to L via the diode D6. At this time, since the state does not change no matter how much the cooking start switch 30 is operated, the operation of the electronic timer circuit is prohibited. The browning adjustment is performed by adjusting the set potential of one input voltage of the voltage comparator A with the volume VR.

[0017]

As described above, according to the present invention, it is possible to start and cancel heating with one switch, and
Since the cooking time can be automatically set without using a microcomputer, the operation panel is simplified and the usability is improved, and it can be configured at a significantly lower cost than a heating cooker to which a microcomputer is applied. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining an embodiment of the present invention.

FIG. 2 is an enlarged view of an operation panel.

FIG. 3 is a circuit diagram for explaining the operation of the embodiment.

FIG. 4 is a perspective view showing the appearance of a conventional toaster.

FIG. 5 is an enlarged view of a conventional operation panel.

FIG. 6 is a block diagram for explaining the operation of the toaster.

FIG. 7 is a circuit diagram.

[Explanation of symbols]

 1 Main body 2 Door 30 Cooking start switch 31 Toast switch 32 Snack switch

Claims (2)

[Claims] 1. A signal control unit for inverting the level of an output signal each time a signal is input, a time-limit circuit composed of a resistor and a capacitor, and a thermistor for detecting the temperature inside the refrigerator, wherein the output signal is at a high level. When, the time limit of the time limit circuit is set based on the temperature detected by the thermistor, and after the set time elapses, the cooking time setting unit that outputs a signal to the signal control unit, and when the output signal is high level, heats the heating unit. And a heating drive unit that stops heating of the heating unit when the output signal is at a low level. 2. The heating cooker according to claim 1, wherein the time constant of the time limit circuit is varied according to the amount of heating.