JPH0411995B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention adjusts the integration start timing of a timer that controls energization to the heater in order to achieve approximately the same finish for the first roasting and the second and subsequent roasting. This invention relates to a control circuit for a toaster oven equipped with a preheating timer.

[Prior art]

In a conventional toaster oven, as shown in FIG. 3, a toaster body 7 has an opening/closing door 3 having a handle 1 and a glass window 2, a timer knob 4, a switch button 5, and a grill 6 inside. The control circuit has a structure as shown in FIG.

First, when the switch button 5 is pressed down to turn on, the micro switch 8 is turned on, and the upper heater 9 and lower heater 10 are energized.

On the other hand, power is supplied to the integrated circuit IC, and the built-in timer is reset by the reset circuit in the integrated circuit IC, and as a result, transistor Q2 is turned on.
turns off, transistor Q3 turns on, and electromagnet 11
is driven, and the microswitch 8 is kept closed.

On the other hand, the capacitor C4 of the preheating timer 12 starts charging, and when the charging of the capacitor C4 is completed, the collector terminal of the transistor Q1 becomes L, and an oscillation start signal is sent to the terminal of the integrated circuit IC, and the built-in timer starts. Start counting.

The preheating timer 12 is used to adjust the time at which the timer starts counting according to the charging time of the capacitor C4, and is designed to make the finished product of the first roasting approximately the same as the finished product of the second and subsequent roastings. The preheating time for the inside of the vessel is made different between the first and second and subsequent times.

That is, at the start of preheating, a charging current flows through the capacitor C4, and the charging time until the charging of the capacitor C4 is completed becomes the preheating time, and the toaster oven is preheated. When the roasting is completed, the capacitor C4 is discharged, and when roasting is continued, the capacitor C4 is not completely discharged. The charging time will be shorter, and the results of the first and second roasting will be the same.

In this way, the time from the end of the previous roasting to the start of the next roasting is proportional to the amount of discharge of the capacitor, that is, the longer the time from the end of the previous roasting to the start of the next roasting, the more the capacitor discharges. The larger the amount, the longer the preheating time for the next roasting, and the shorter the time from the end of the previous roasting to the start of the next roasting, the smaller the amount of capacitor discharge and the shorter the preheating time for the next roasting. Become.

When the timer reaches a predetermined time, the terminal output of the integrated circuit IC becomes H, transistor Q2 is turned on, transistor Q3 is turned off, and the microswitch 8 is released from holding.

In the drawing, VR1 is a variable resistor for adjusting the shade of baked goods, C1 to C8 are capacitors, R1 to R15 are fixed resistors, D1 and D2 are diodes, and ZD1 to ZD3 are Zener diodes.

By the way, in the above control circuit,
The preheating time of the preheating timer 12 has no relation to the output of the heater, and therefore it is not possible to perform detailed control when the cooking menu changes.

In other words, in the case of toast, the preheating time is approximately 75 seconds.
In the case of kutsky and madeleines, about 180 seconds of subtime is required, and unless you change the preheating time depending on the cooking menu, it is not possible to achieve the same results from the first and second cooking.

〔the purpose〕

An object of the present invention is to change the preheating time of the preheating timer by switching the output of the heater according to the cooking menu.

〔Example〕

FIG. 1 is an electrical circuit diagram of the present invention, and the same parts between the present invention and the conventional example are indicated by the same reference numerals.

The upper heater 9 is connected in series to the diode D4, and this series circuit is connected in parallel to the series circuit of the lower heater 10 and the second changeover switch 13, and both ends of this parallel circuit are connected to the power plug 14 side. There is.

15 is the lower heater 10 and the second changeover switch 13
and between the upper heater 9 and the diode D4, and one end thereof is connected to the midpoint between the capacitor C9 and the resistor R16, which are connected to the output terminal side of the diode D4. It is connected.

Q5 is a transistor, and its base terminal is connected to the resistor R16 via the diode D3. When the transistor Q5 is energized, the transistor Q4 is turned off, and the capacitor C4 of the preheating timer 12 is connected to the Zener diode.
The total Zener voltage of ZD2 and ZD4 is applied and charged. Also, conversely, transistor Q5
is turned off, transistor Q4 is turned on, and at this time, the capacitor C of the preheating timer 12 is turned on.
The Zener voltage of only the Zener diode ZD2 is applied to the Zener diode ZD2, and the Zener diode ZD2 is charged.

That is, when the transistor Q5 is ON, the total Zener voltage of the Zener diodes ZD2 and ZD4 is applied to the capacitor C4 via the resistor R12.
Therefore, the capacitor C
4 reaches a predetermined voltage (the voltage that makes transistor Q1 conductive) quickly, and therefore the preheating time by preheating timer 12 is shortened. On the other hand, when transistor Q5 is OFF and transistor Q4 is ON, capacitor C4 is charged with only the Zener voltage of one Zener diode ZD2, so it takes time for capacitor C4 to reach the predetermined voltage. As a result, the preheating time by the preheating timer 12 becomes longer.

In this way, transistor Q4 or Q5
The ON operation changes the preheating time of the preheating timer 12 to correspond to the type of cooking menu. Incidentally, in the embodiment of the present invention, when the preheating time when the transistor Q5 is ON is short, it is set to toast, and when the transistor Q4 is ON and the preheating time is short, it is set to ``Kutsky'' or Madeleine.

Note that R15 is a fixed resistor for voltage division, and C10 is a capacitor for driving a transistor.

Therefore, when roasting toast with a relatively short preheating time, if the micro switch 8 is closed and both the first changeover switch 13 and the second changeover switch 15 are closed, the upper heater 9 and the lower heater 10, the heating output is maximized, and an AC voltage divided by the resistor 16 and the resistor 15 is applied to the diode D3, and the diode D3 and the capacitor C10 It is rectified by , transistor Q5 turns on,
Due to the above-mentioned reasons, the preheating time of the preheating timer 12 is shortened.

Next, when roasting kutsky which requires a relatively long preheating time, turn on the second changeover switch 15,
When the first changeover switch 13 is turned OFF, a half-wave current flows through both the upper heater 9 and the lower heater 10, and the heating output becomes the minimum, while a half-wave rectified voltage is applied to the diode D3 side, but the capacitor C10
The voltage across the terminal becomes 0, and the transistor Q5 becomes
It turns OFF, and transistor Q4 turns ON. Therefore, the preheating time of the preheating timer 12 becomes longer for the reasons described above.

Incidentally, if you want to roast the pizza, turn off the second changeover switch 15 and turn on the first changeover switch 13.
In this case, an AC voltage is applied to the lower heater 10, a half-wave rectified voltage is applied to the upper heater 9, and the heating output becomes a "medium" output. Also, in this case, one end of the resistor 16 becomes a half-wave rectified voltage, and as in the case of Kutsky roasting, the transistor Q5 is turned off and the transistor Q4 is turned on.

〔effect〕

As described above, the present invention adjusts the integration start timing of the timer that controls energization to the heater using the charging/discharging time of the capacitor in order to achieve approximately the same finish for the first roasting and the second and subsequent roasting. In the control circuit of a toaster oven equipped with a preheating timer, there is an output changeover switch that changes the output of the heater, and the switching operation of the output changeover switch changes the capacitor charging current and adjusts the preheating time of the preheating timer. Since it is equipped with a variable means, in order to almost eliminate the difference between the first and second roasting results, you can use the conventional preheat timer condenser and simply switch the heater output, which is different from conventional toaster ovens. It is possible to perform preheating for dishes such as cutlets and madeleines, which were considered difficult to prepare, and it is also possible to easily roast cutlets and madeleines, and it is also possible to obtain a good finish for pizzas, hot dogs, etc. .

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram of a control circuit of the present invention, FIG. 2 is an electric circuit diagram of a conventional control circuit, and FIG. 3 is an external perspective view of a conventional toaster oven. Q1: Transistor, C4: Capacitor,
ZD2, ZD4: Zener diode, D4: Diode, 9, 10: Upper and lower heaters, 12: Preheat timer, 13: 1st changeover switch, 15: 2nd
Changeover switch.

Claims (1)

[Claims] 1. In order to achieve substantially the same finish for the first roasting and the second and subsequent roasting, the integration start timing of a timer that controls energization to the heater is adjusted using the charging/discharging time of the capacitor. In the control circuit of a toaster oven equipped with a preheating timer, there is an output changeover switch that changes the output of the heater, and the switching operation of the output changeover switch changes the capacitor charging current and adjusts the preheating time of the preheating timer. A control circuit for a toaster oven characterized by being equipped with variable means.