JPH043816A - Power switching device for cooker - Google Patents

Abstract

PURPOSE:To prevent the risk of unwilling application of power by closing a first contact after a specified time has elapsed in accordance with a program after a microcomputer has released reset when a power switch is turn on. CONSTITUTION:The operation of a switch 4 course source voltage rise, releases the reset of microcomputer 7, and the zero-point signal of AC power source is counted. When the preset time is reached, a first relay is turned on to maintain the AC power source, starting the next step of cooking action. To turn off the power source switch, a key switch 9 is operated. Then, a second relay contact 6 is opened. Next, the first relay contact 1 is opened, and the self-hold is released. This prevents the risk of unwilling application of power.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the construction of a power switch device for a cooking appliance that self-holds a relay contact by operating a switch.

BACKGROUND OF THE INVENTION In recent years, power switch devices for cooking appliances have come to be self-maintained using relays in order to enable one-touch operation.

Conventionally, the power switch of this type of cooking appliance has generally had a configuration as shown in FIG. The configuration will be explained below.

As shown in the figure, a bushing switch 16 is provided on the power supply line, and charges a capacitor 18 through a resistor 17, and when this charging voltage reaches a certain voltage,
'19 is driven, and the relay contacts 20 and 21 close to perform a self-holding operation. Then, the load 22 is energized via the relay contact 21 to perform the cooking operation. During this time, the capacitor 24 is charged via the resistor 23, and when the terminal voltage of the capacitor 24 rises to a constant voltage, the PUT 25 is turned on. As a result, the transistor 26 is turned off and the transistor 27 is turned on, so that the capacitor 1sVi is discharged, the current in the relay coil (v19) becomes almost 0, self-holding is canceled, and the relay contacts 20 and 21 are opened to complete the operation.

Problems to be Solved by the Invention In such a conventional power switch for a cooking appliance, the time required for self-holding when the button switch 16 is operated is determined by the time constant of the resistor 1 and the capacitor 18, so five components are required. This resulted in time variations of a degree of variation. Moreover, it has the disadvantage that even a brief operation, such as accidentally touching the bushing switch 16, will cause the switch to close. The present invention solves the above problem by setting the turn-on time using a CR timer using PUT25. The first priority is to be able to set the time arbitrarily and accurately.
The purpose is to

A second purpose is to enable accurate setting of the time until the power is automatically turned off even if it is a long time. Furthermore, a third objective is to improve usability by providing a notification using a notification means while the switch is being operated.

Means for Solving the Problems In order to achieve the above first object, the present invention provides a first relay contact connected to a power supply line of a load circuit and a control circuit;
A microcomputer connected in parallel to the first relay contact, a drive circuit for the first and second relays connected to a high-power terminal of the microcomputer, and a key switch for inputting input to the microcomputer, the switch When the power is turned on by operating the key switch, the microcomputer measures a certain period of time according to a program after canceling the reset, drives the first relay after a predetermined time has elapsed, and when the key switch is operated, the microcomputer measures the period of time according to a program. The first problem-solving means is that the first relay contact is turned off after the second relay contact is turned off.

In order to achieve the second purpose, in addition to the first problem-solving means described above, in place of the key switch, a microcomputer drives the first relay contact and then measures a certain period of time according to a program. A second means for solving the problem is to turn off the second relay contact and then turn off the first relay contact after a predetermined time has elapsed. Furthermore, in order to achieve the third purpose,
Alternatively, in addition to the second problem solving means, a notification means is provided in the control circuit, and the notification means is activated when the switch is operated.
The third means for solving the problem is that the first relay contact is activated, and when the first relay contact is activated, the first relay contact is activated with a different tone.

Effect of the Invention According to the first problem-solving means described above, the power switch of the aircraft body can be a switch connected in parallel to the first relay contact, and when the switch is operated, the first relay is turned on and the self-power switch is turned on. At this time, the time interval for operating the switch to make the first and second relays self-hold can be arbitrarily set using a microcomputer program, and the accuracy of the time is also very high. Become something.

In addition, the second problem solving means can automatically release the self-holding of the first and second relays after a certain period of time, and the time accuracy at this time can be set very accurately.
Basically, the length of time can be set without any limit. Furthermore, according to the third problem solving means, even if the switch is operated by mistake, the user can be notified by using the notification means while the switch is being operated, and it is possible to determine how long the switch should be held down. .

EXAMPLES Hereinafter, examples of the first and second problem solving means will be described with reference to FIG.

As shown in the figure, a first relay contact 1 is connected to a power supply line of a load circuit 2 and a control circuit 3, and a switch 4 is connected in parallel to the first relay contact 1. The load circuit 2 is a load, in this case an electric heating element 5 for heating and this electric heating element 5.
The power consumption of the electric heating element 5 is controlled by turning on and off the second relay contact 60, and the heating power is adjusted.

The control circuit 3 is provided with a microcomputer 7,
This microcomputer 7 has a timer function that operates after a reset configured by a program.This timer function measures a certain period of time, and when the first set time has elapsed, the relay assembly circuit 8 activates the first relay contact. Close 1. The key switch 9 is connected to the input of the microcomputer 7 and is operated to turn off the power switch. The display means 10 displays cooking operations and is constituted by an LCD. The power supply circuit 11 supplies DC voltage to the control circuit 3 including the microcomputer 7. Further, this power supply circuit 11 supplies a zero point signal synchronized with the zero point of the AC power source to the microcomputer. Time is measured by counting zero point signals synchronized with this zero point. The relay drive circuit 12 is a drive circuit for the second relay contact 6 which is turned on and off to set the firepower.

In the above configuration, the operation of the first problem solving means will be explained with reference to the flowcharts of the microcomputer 7 shown in FIGS. 2 and 3.

First, when turning on the power switch, operate the switch 4 to raise the power supply voltage, and when the reset of the microcomputer 7 is released, the first step S1 in FIG.
In step S2, the zero point signal of the AC power supply is counted and T is increased by ΔT, and then in the second step S2, T is set as a constant for a time T.

If T has not reached To, the first step S1 is repeated again. If T reaches To, then
In the third step S, the first relay 1 is turned on to maintain the AC power, and the process moves to the next step such as cooking operation.

Next, when turning off the power switch, operate the key switch 9, and when this is detected in the first step S11 of FIG. 3, the process moves to the second step S12, and first the second relay contact 6 is turned off. . Next, in the third step S13, the first
Turn off relay contact 1 and release self-holding. The above routine turns off the power switch.

As described above, according to the power switch of the cooker according to the embodiment of the first problem solving means, if the switch 4 is operated for a certain period of time, the power will not be turned on, and the time can be set arbitrarily and accurately. As a result, there is no danger of accidentally turning on the power inadvertently.

Next, the operation of the second problem solving means will be described with reference to FIG. 4 in the case where the power switch is turned off. Note that the on-operation is the same as the on-operation of the first problem-solving means described above, so a description thereof will be omitted.

After a certain period of time has elapsed since the power switch was turned on, the process jumps to the first step S21 from the previous step of the cooking operation, and in the first step S21, T' is increased by ΔT'. Next, in the second step S22, it is compared whether T' is greater than the second set time T2.
23, and turns off the second relay contact e. Next, the first relay contact 1 is turned off in a fourth step S24 to release the self-holding state.

As described above, according to the power switch of the cooker according to the embodiment of the second problem solving means, the power can be automatically turned off after a certain period of time has passed, and the set time is one hour corresponding to cooking.
Even if it is a long time such as 2 hours, it can be set accurately and without variation.

Next, an embodiment of the third problem solving means will be described with reference to FIG. Components having the same configuration as those in the above embodiment are given the same reference numerals and explanations will be omitted.

As shown in the figure, the control circuit 13 includes a buzzer (notification means) 1
4, the microcomputer 15 has a timer function that operates after being reset, and this timer function measures a certain period of time, during which time it drives the buzzer 14 used as a notification means. Then, after the first set time has elapsed, the relay drive circuit 8 closes the υ first relay contact 1.

Further, at this time, the buzzer 14 is made to sound intermittently for a short period of time.

In the above configuration, the operation when turning on the power switch will be described with reference to FIG. 6 and FIGS. 7(a) to (C). Note that the off-operation is the same as in the first and second embodiments of the problem-solving means described above, so a description thereof will be omitted.

First, when turning on the power switch, operate the switch 4 to ensure that the power supply voltage does not rise and the microcomputer 15
When the reset is released, the first nutep S3 in FIG.
1, the number of 7-cut signals from the AC power source is counted and T is increased by ΔT, and then, in the second step S32, the buzzer 14 is sounded. Next, in a third step S33, T is compared with a time To set in advance as a constant, and if T has not reached To, the process returns to the first step 831 again. T is To
If this has been reached, the fourth step S34 turns on the first relay contact 1 to maintain the AC power supply, and the fifth step 835 drives the buzzer 14 intermittently or at a different frequency for a short time. After that, move on to the next step, such as adjusting the firepower.

7(a) to 7(c) are waveform diagrams illustrating the outline of the above operation, and FIG. υAfter a certain period of time, the third
Relay contact 1 turns on. Buzzer 14 is shown in Figure 7 (C)
After the resent of the microcomputer 15 is released, the sound continues until the relay contact 1 of the cylinder 1 is turned on, and when the first relay contact 1 is turned on, the sound is emitted intermittently for a short period of time.

As described above, according to the power switch of the cooker according to the embodiment of the third problem-solving means, the buzzer 1 can be activated by operating the switch 4.
Even if the user accidentally operates the switch 4 without realizing it until a warning is given with a sound, the user will be able to notice it, and if the first relay contact 1 is self-holding, the tone will be different, and the user will be able to see how much the switch 4 is opened. You will know what to do next and improve usability.

Effects of the Invention As is clear from the above embodiments, according to the present invention, when the switch is operated to turn on the power, the microcomputer releases the reset and then measures a certain period of time according to the program, and the predetermined time elapses. Since the relay contact on the rear tube 1 is driven, the power will not be turned on unless the switch is operated for a certain period of time, and this time can be set arbitrarily accurately, thereby preventing accidental malfunctions. Its practical value is high, as it eliminates the risk of power being turned on intentionally. In addition, the microcomputer measures a certain period of time according to a program, and after a predetermined period of time has elapsed, the second relay contact is turned off, and then the first relay contact is turned off. It can be turned off automatically, and the set time is 1 hour, which corresponds to cooking.

Even if it is a long time such as 2 hours, it can be set accurately and without variation. Furthermore, a notification means is provided in the control circuit, and when the switch is operated, the notification means gives a notification when the first relay contact is driven, and when the first relay contact is driven, it gives a notification with a different tone. , the opening sound when the switch is operated alerts you, so even if you accidentally operate it without knowing it, you can notice it. Also, when the first relay contact is self-holding, it makes a different tone, indicating how much the switch is being operated. User-friendliness can be improved by knowing whether or not to keep opening the door.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a power switch device of a cooking appliance according to an embodiment of the present invention, Fig. 2 is an operation flowchart of the power switch device of the cooking appliance when the power is turned on, and Fig. 3 is a power switch of the cooking appliance. Operation flowchart when the device is powered off,
FIG. 4 is an operation flowchart when the power switch device for a cooker according to another embodiment of the present invention is powered off, FIG. 5 is a block diagram of the power switch device for a cooker according to another embodiment of the present invention, and FIG. The figure is a flow chart of the operation of the power switch device of the same cooker when the power is turned on, and Figures 7 (a), (b), (C
) are operating waveform diagrams of the power switch device of the cooking appliance, and FIG. 8 is a circuit diagram of the conventional power switch device of the cooking appliance. 1...First relay contact, 2...Load circuit, 3...Control circuit, 4...Switch, 5...Electrical heat generation Body (load), 6...
2nd relay contact, 7... microcomputer, 8... relay drive circuit, 9... key switch, 12... relay drive circuit.

Claims (3)

[Claims] (1) The first terminal connected to the power supply line of the load circuit and control circuit.
and a switch connected in parallel to the first relay contact, the load circuit is formed by connecting the second relay contact to the load, and the control circuit includes a microcomputer and a switch connected in parallel to the first relay contact. a drive circuit for the first and second relays to which the outputs of the relays are connected, and a key switch for inputting input to the microcomputer,
When the switch is operated to turn on the power, the microcomputer releases the reset and measures a certain period of time according to a program, and after a predetermined period of time has elapsed, drives the first relay contact and operates the key switch. The power switch device for a cooking appliance is configured to turn off the second relay contact and then turn off the first relay contact. (2) Instead of a key switch, the microcomputer drives the first relay contact, measures a certain period of time according to a program, turns off the second relay contact after the predetermined time has elapsed, and then switches the second relay contact to the first one. 2. The power switch device for a cooker according to claim 1, wherein the power switch device is configured to turn off a relay contact. (3) A notification means is provided in the control circuit, and the notification means provides notification until the first relay contact is driven when the switch is operated, and provides notification with a different tone when the first relay contact is driven. A power switch device for a cooker according to claim 1 or 2, comprising: