JPS63161911A - 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 that include an electric heating element.

Conventional technology Conventional electric ranges mainly consisted of an electric heating element such as a sheathed heater and a controller for adjusting the heating power, but in recent years electronic circuits have been used to Devices that can shut off the power and stop heating if the temperature rises abnormally are beginning to appear. An example of such an electric range is shown in FIG.

In FIG. 4, 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 drive circuit 3, and the drive circuit 3 is controlled by a temperature detection circuit 4. Note that 5 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. This state continues if the temperature of the heated object is the temperature under normal usage conditions.

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 5 cannot detect this dry firing state either. Furthermore, 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 to Solve the Problems In order to solve the problems above, the present invention provides an electric cooking device 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 or the like, a driving means controlled by the temperature detection circuit, a power control means driven by the driving means and connected in series to the electric heating element, and a temperature sensing circuit placed on the electric heating element. A safety device is constructed by including a safety switch that is activated by the object to be heated, and connecting the contacts of the switch to the output side of the drive means.

Effect: With the above configuration, when the object to be heated is placed on the electric heating element, the safety switch is activated and prohibits the input of the drive means 1. Therefore, the drive of the power control means is forcibly stopped. energization 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 the object is removed, the energization can be stopped.

Embodiment FIG. 1 to FIG. 3 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. Reference numeral 6 denotes a contact point of a safety switch driven by the object to be heated, and is connected to the output side of the relay drive circuit 3.

Now, if contact 6 is closed and the temperature is normal, relay contact 2 is closed.
is closed and the main switch is on, the electric heating element 1 is energized.

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 6 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
is connected by a lever 9.10. 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, 5 is a temperature detection element, 6
12 is a voltage comparator, 13 is a relay coil plate, 14 is a transistor, and these relay coil 13 and transistor 14 are connected.
constitutes the 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 5 drops below a predetermined value due to abnormal temperature, or when the object to be heated is removed and the contact 6 is measured, the transistor 14 is turned off and the relay contact 2 is turned off. It is opened to stop energizing the electric heating element 1.

Effects of the Invention As is clear from the description of the embodiments, if 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, which reduces the operating temperature of the electric heating element and extends its life. It is possible to extend the temperature and also eliminate the adverse effects of temperature on the main body.

In particular, the current flowing through the contacts of the safety switch is small, allowing the use of a switch with a small capacity and improving its reliability.

[Brief Description of the Drawings] Fig. 1 is a block diagram of a safety device of an electric cooker showing an embodiment of the present invention, Fig. 2 is a sectional view of the safety switch section, Fig. 3 is a circuit diagram of the same, FIG. 4 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 3

Claims (1)

[Claims] A cooking device such as an electric range having an electric heating element,
A temperature detection element, a temperature detection circuit that compares and outputs the detected voltage, a drive means driven by the output, a power control means connected in series to the electric heating element, and a temperature detection circuit mounted on the upper part of the electric heating element. 1. A safety device for an electric cooker, comprising a safety switch means that is activated by a heated object placed therein, and a contact point of the safety switch is connected to an output side of the drive means.