JPS63161910A - Safety apparatus of electric cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a safety device for cooking appliances such as electric ranges having electric heating elements.

Conventional technology Conventional electric ranges mainly consisted of an electric heating element such as a sheathed heater and a wattage controller to adjust the heating power, but in recent years electronic circuits have been used to adjust the temperature of the heated object. Devices are beginning to appear that can shut off the power and stop heating if the temperature rises abnormally. An example of such an electric range is shown in FIG. In Figure 5,
Reference numeral 1 denotes an electric heating element such as a sheathed heater, and a relay contact 2 is inserted into its energizing circuit. The relay contact 2 is controlled by a relay coil and a coil motion circuit 3,
The drive circuit 3 is controlled by a temperature detection circuit 4. Note that 6 is a temperature detection element such as a negative characteristic thermistor. The operation of this configuration is as follows.

Now, when the electric heating element 1 is energized, the relay contact 2 is in a closed state. If the temperature of the object to be heated is the same as the temperature in the normal usage state, this state will continue.

Next, when the temperature of the object to be heated becomes abnormal, the temperature detection circuit 4 is activated due to a change in the resistance value of the temperature detection element 5 provided in contact with the object to be heated, and the drive of the relay coil 3 is stopped. Contact 2 is opened to stop heating.

Problems to be Solved by the Invention However, the configuration of the electric range described above has the disadvantage that when the power switch is turned on, electricity is applied even though there is no object to be heated, and the electric heating element 1 becomes high temperature. was. Since the temperature detection element 6 is provided so as to be in contact with the object to be heated, the temperature detection element 6 cannot detect this dry firing state either. Further, when the electric heating element 1 reaches a high temperature, its lifespan is shortened, and various parts of the main body are adversely affected by the heat.

Means for Solving the Problems In order to solve the above problems, the present invention is an electric cooker having an electric heating element, which compares and outputs the detected voltage with a temperature detection element such as a negative characteristic thermistor. a temperature detection circuit including a voltage comparator, a drive circuit controlled by the temperature detection circuit, and a drive circuit driven by the drive circuit;
A power control means connected in series to the electric heating element, and a safety switch operated by a heated object placed on the electric heating element, the contacts of the safety switch being connected to the input side of the pre-installed drive circuit. to configure the safety device.

Effect: With the above-described configuration, when the object to be heated is placed on the electric heating element, the safety switch is activated and prohibits input of the driving means. Therefore, the drive of the power control means is forcibly stopped and the supply of electricity to the electric heating element is stopped.

As described above, when the object to be heated is placed, the electric heating element is energized, and when it is removed, the energization can be stopped.

Embodiment FIG. 1 to FIG. 4 show an embodiment of the present invention. FIG. 1 is a block diagram showing an embodiment of the present invention, in which 1 is an electric heating element, 2 is a relay contact, 3 is a relay drive circuit, and 4 is a block diagram showing an embodiment of the present invention.
5 is a temperature detection circuit consisting of a voltage comparator, etc., and 5 is a temperature detection element, which are the same configuration as the conventional example.
The explanation will be omitted. 6 and 6' are the contacts of a safety switch that is driven by the object to be heated, and the relay-video path 3
connected to the input of

Now, if contact 6 is closed and the temperature is normal, relay contact 2 is closed.
is closed and the main switch is on, energizing the electric heating element.

FIG. 2 is a sectional view showing the configuration of a safety switch operated by a heated object. 1 is an electric heating element, and 5 is a temperature detection element. The case 7 of the temperature detection element 5 is heated upward by a spring 8. And switch 6 is case 7
are connected to each other by levers 9 and 10. Therefore, when the case 7 is pushed down by the pot 11 which is the object to be heated, the contact of the safety switch 6 is closed by the lever 1°.

FIG. 3 shows an example of a specific circuit configuration of the temperature detection circuit 4 and the drive circuit 3. In FIG. 3, 6 is a temperature detection element;
6 is a contact point of a safety switch activated by the object to be heated, 1
2 is a voltage comparator, 13 is a relay coil, 14 is a transistor, and these relay coil 13 and transistor 1
4 constitutes a drive circuit. When there is an object to be heated, the contact 6 is closed.

In this circuit, when the resistance value of the temperature detection element 6 is abnormal - when the temperature drops to a predetermined value or when the object to be heated is removed and the contact 6 opens, the transistor 14 turns off and the relay contact 2 to stop supplying electricity to the electric heating element 1.

FIG. 4 shows contact 6 when there is an object to be heated in another embodiment.
Connect so that it opens. Similarly, in this circuit, when the object to be heated 12 is removed and the contact 6 is opened, the base of the transistor 14 becomes low level, the transistor 14 is turned off, the relay contact 2 is opened, and the electricity to the electric heating element 1 is stopped. Stop.

Effects of the Invention As is clear from the explanation of the embodiments above, when the safety device of the present invention is used, when there is no object to be heated, the electricity to the electric heating element is stopped, so the temperature of the electric heating element decreases. In addition to extending the lifespan, the negative effects of temperature on the main body can also be eliminated.

Furthermore, the current flowing through the switch contacts is small, allowing the use of switches with small capacitance and improving reliability.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a safety device for an electric cooker showing one embodiment of the present invention, Fig. 2 is a sectional view of the safety switch section, and Fig.
4 and 4 are the same circuit diagrams, and FIG. 6 is a block diagram of a conventional electric range. 1... Electric heating element, 2... Relay contact (power control means), 4... Temperature detection circuit, 5...
...Temperature detection element, 6...Safety switch contact. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 13rI! J L −m−−+ −−−−−−−J Fig. 5

Claims (1)

[Claims] A cooking appliance such as an electric range that has an electric heating element, including a temperature detection element, a temperature detection circuit that compares and outputs the detected voltage, a drive circuit that is driven by the output, and is connected in series to the electric heating element. and a safety switch operated by an object to be heated placed on top of an electric heating element, the contact of the safety switch being connected to the input side of the drive means. Safety device.