JPS6010507Y2 - Empty cooking prevention device for electric cookers - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an empty cooking prevention device for an electric cooker having a structure in which an inner pot is housed within the cooker main body.

This type of electric cooker is, for example, an electric rice cooker, an electric pot,
There are boiled food jars, etc., but in rare cases, these jars are turned on without the inner pot (rice bowl) being placed, resulting in what is called an empty cooking state.

Electric cookers designed to prevent such dry cooking have been known in the past, but conventional dry cooking prevention devices have a structure that uses mechanical contacts to detect the presence or absence of an inner pot inside the cooker body. Therefore, considerably high precision is required in the dimensions and assembly of various parts such as these contacts and levers for operating the contacts, which is an obstacle to reducing parts costs and assembly costs.

Furthermore, levers for attaching contacts and the like may become deformed during long-term use, resulting in a lack of long-term reliability.

In view of the above-mentioned problems with conventional dry cooking prevention devices, the present invention detects the inner pot using a non-contact switch, thereby providing an electric cooker equipped with an inexpensive and highly reliable dry cooking device. It was done for the purpose of

The following describes the electric cooker (electric rice cooker with heat retention function) according to the embodiment of the present invention shown in the accompanying drawings. In FIG. 4 and place the cooking heater 1 on the bottom of the inner case.
1 is placed and fixed thereon.

A heat-retaining heater 8 having two systems of heating elements 12 and 13 is attached to the upper outer periphery of the inner case 2.
After cooking, the inner pot (rice bowl) 10 housed in the inner pot (rice bowl) 10 is connected to the heat-retaining heater 8 and the heat-retaining lid heater 9 provided in the lid 7.
It is designed to be kept warm by

Attached to the center of the heating platen 5 is a sensor unit 6 that includes a temperature sensor 21 for detecting the completion of cooking and a non-contact switch A for preventing dry cooking, which will be described later.

In the embodiment of FIG. 1, a sensor unit 6 as shown in FIG. 2 is used.

In this sensor unit 6, an inner case 25 is supported in a floating state by a spring 26 within an outer case 24, and the inner case 25 projects slightly above the upper surface of the heating plate 5 in a free state.

A temperature sensor 21 that detects the high temperature at the end of cooking is attached to the lower surface of the top plate of the inner case 25, and the detection signal of this temperature sensor 21 is sent to the cooking control circuit Y (No. (Fig. 3).

A photo sensor is attached to the bottom upper surface of the outer case 24 as a non-contact switch A.

The photo sensor is constructed by attaching a light emitting element 31 and a light receiving element 32 to a concave base 30 with a gap 33 in between.
When the light from the light emitting element 31 is received by the light receiving element 32,
The light receiving element 32 is turned on.

A light shielding member 34 is attached to the lower surface of the bottom of the inner case 25 and moves in and out of the photo sensor gap 33 as the inner case 25 moves up and down.

FIG. 3 shows an electric circuit when the sensor unit 6 shown in FIG. 2 is used.

In FIG. 3, the symbol X is the heating main circuit including the cooking heater 11, the heating elements 12, 13 of the side heat retaining heater 8, and the lid heater 9, and Y is the main opening/closing switch 14 for the cooking heater 11.
A cooking control circuit having a temperature sensor 21 and a relay 22 for controlling the temperature, and 2 a cooking control circuit having a non-contact switch A for preventing dry cooking.

The electrical circuit of FIG. 3 operates as follows.

That is, when the inner pot 10 is housed in the cooking device main body 1 (FIG. 1) prior to the start of cooking, the inner case 25 of the sensor unit 6 (FIG. 2) is lowered, and the light shielding member 34 blocks the light emitted by the photosensor A. The element 31 and the light receiving element 32 are cut off.

At this time, the photo sensor A is placed in a de-energized state, and as a result, the relay 37 of the dry cooking prevention circuit Z is also de-energized, so the normally closed contact 16 incorporated in the main heating circuit
The circuit is maintained in a closed state without receiving the operating force of 7.

On the other hand, when the inner pot 10 is not housed in the cooking device main body 1, light is exchanged between the light emitting element 31 and the light receiving element 32 in the photosensor A.
becomes energized, and as a result, relay 37 becomes energized via transistor 36.

When the relay 37 is energized, its normally closed contact 16 is opened, so even if the main switch 14 is turned on, no current is supplied to the cooking heater 11, and therefore no dry cooking occurs.

When the switch button 18 (Fig. 1) is pressed down while the inner pot 10 is housed in the cooker body 1, that is, the normally closed contact 16 of the relay 37 is closed, the main open/close switch 14 is turned on. Then, the cooking heater 11 is energized and the cooking action is started.

Incidentally, during cooking, the lid heater 9 is also energized to heat the inner pot 10 from the top surface as well.

When the cooking process is finished, the temperature sensor 21 detects a sudden rise in temperature at the bottom of the inner pot 10 and activates the relay 22.
The main open/close switch 14 is opened.

After the cooking action is completed, the two heating elements 1 of the side heat retaining heater 8
2, 13 and the lid heater 9 perform a heat retention effect.

In FIGS. 1 and 3, reference numeral 15 is a temperature-sensitive reed switch that detects the temperature of the inner pot 10 and controls the heat generation of the heating element 12 to keep the inner pot at an appropriate temperature.

4 and 5 show a sensor unit 6 and its circuit used in another embodiment of the present invention.

In this embodiment, a non-contact switch A configured by combining a Hall element 41 and an amplifier 42 is used.

The circuit Z shown in Fig. 5 is converted into the dry cooking prevention circuit Z shown in Fig. 3.
In other words, the same effect of preventing dry cooking as in the above embodiment can be achieved.

That is, in the sensor unit shown in FIG.
A magnet 44 is attached to the bottom of the pot, and when the magnet 44 approaches the Hall element 41 (when the inner pot 10 is housed), a voltage is induced in the Hall element 41, and this voltage is amplified by the amplifier 42. The relay 37 is energized via the transistor 36.

In the case of the second embodiment, the normally open contact 16' is used as the contact of the relay 37, and when the relay 37 is activated (when the inner pot is housed)
In this case, the normally open contact 16' closes the current supply circuit to the cooking heater 11.

Moreover, when the magnet 44 is separated from the Hall element 41 (when the inner pot 10 is not housed), the voltage necessary to operate the relay 37 is not induced in the Hall element 41,
Therefore, the normally open contact 16' of the relay 37 is maintained in an open state, and energization to the cooking heater 11 is blocked.

As mentioned above, since the present invention uses the non-contact switch A as the inner pot detection means, various parts such as the lever for contact operation are Strict dimensional accuracy and assembly accuracy are not required, and the manufacturing cost and assembly cost of parts can be reduced.

[Brief explanation of the drawing]

Fig. 1 is an internal structure diagram of an electric cooker according to an embodiment of the present invention, Fig. 2 is an enlarged longitudinal cross-sectional view of a sensor unit used in the electric cooker of Fig. 1, and Fig. 3 is a diagram of the structure shown in Fig. 1. FIG. 4 is a longitudinal sectional view of a sensor unit in another embodiment of the present invention, and FIG. 5 is an electric circuit of an air-cooking prevention device when the sensor unit of FIG. 4 is used. It is a diagram. 1... Cooker body, 6... Sensor unit, 10... Inner pot, 11... Cooking heater, 14... Main Open/close switch, 24...
...Outer case, 25...Inner case, A...
...Non-contact switch.

Claims (1)

[Scope of utility model registration request] In an electric cooker in which an inner pot 10 is housed in a cooker main body 1 having a cooking heater 11 inside, there is a space between an outer case 24 and an inner case 25 which is movable relative to the outer case 24. The inner case 25 is connected to the cooker by interposing a sensor unit 6 with a non-contact switch A that separates or approaches according to the displacement of the inner case 25 and allows or cuts off electricity supply according to the distance or proximity. The inner pot 10 is installed at an appropriate position in the cooking device main body 1 so as to be displaceable as the inner pot 10 is moved in and out of the main body 1, and when the inner pot 10 is not housed in the cooking device main body 1. The dry cooking prevention device for an electric cooker is characterized in that the non-contact switch A acts in a direction to prevent electricity from being applied to the cooking heater 11.