JPH0357597B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operating device for a high-frequency heater such as a so-called microwave oven, and its purpose is to improve the characteristics of a keyboard with respect to temperature changes.

Conventionally, some operating devices for high-frequency heaters have a keyboard on the operating panel, and in the operating devices having the keyboard, a back plate is attached to the back side of the keyboard for reinforcement.
In addition, the keyboard has an air vent hole for each key, allowing air to escape from the back of the keyboard, making it easier to operate the keyboard when turning the keyboard on and off, and also allowing air to escape at high temperatures, allowing the display surface of the keyboard to bulge. was preventing In this way, you can easily create an air vent in the keyboard itself,
As mentioned above, since the back plate is formed on the back side of the keyboard, the relationship with the back plate affects the air venting characteristics of the keyboard. Conventionally, the back plate had air holes that corresponded to the air vent holes in the keyboard, or a groove was provided in the area where the air vent holes in the keyboard came into contact.

However, this conventional method lacks compatibility. In other words, if the position of the air vent hole in the keyboard was changed, the air venting effect of the back board would disappear, making it unsuitable for mass production of multiple models.

A conventional example will be specifically explained below.

In FIG. 7, air vent holes 29 in the back plate 28 are provided in correspondence with air vent holes 27 in the keyboard 13 for air venting. For this reason, a separate back board 28 is required for each type of keyboard 13, and the back boards 28 cannot be used interchangeably, making it unsuitable for mass production. Further, since the back plate 28 requires hole machining, rust may occur in the machined portion.

The present invention solves the above-mentioned conventional drawbacks, and by providing at least four protrusions around the back plate and creating a gap between the keyboard and the back plate, the gap and the outside are breathable and air is removed. It is something. Since there is a gap between the keyboard and the back plate, even if the key layout changes, the air venting effect will not be affected.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An operating device for a high-frequency heater, which is an embodiment of the present invention, will be described below with reference to the drawings.

FIGS. 1 and 2 are diagrams showing the configuration of a high-frequency heater, in which a high-frequency oscillator 1 that oscillates microwaves of 2450 MHz is coupled to a metal waveguide 2 and an antenna 3. Waveguide 2 from high frequency oscillator 1
The high frequency wave radiated into the inside of the waveguide 2 propagates inside the waveguide 2 and is further radiated into the heating chamber 4. Heating chamber 4
The high frequency waves radiated to the cooking object 5 are absorbed by the cooking object 5 placed in the heating chamber 4, and the cooking object 5 is absorbed from the inside of the cooking object 5.
dielectrically heated. Furthermore, the high frequency oscillator 1 is self-heated due to internal loss, and is constantly cooled by the blower fan 6 during oscillation to prevent failure.

A door 7 that can be opened and closed is provided in the front of the heating chamber 4, and an electrical component room 8 is provided on the side of the heating chamber, which includes a high frequency oscillator 1, a blower fan 6, a high voltage transformer 9 for applying high voltage to the high frequency oscillator, and a high voltage capacitor. 10 is located. An operation panel 11 is constructed on the front side of the electrical parts room, and includes a digital display section 12, a keyboard 13, and the like.

FIG. 3 shows the control circuit of the high-frequency heater, and the power plug 14 is designed to prevent short circuits and ground faults in the electrical components that make up the high-frequency heater, as well as excessive leakage of microwaves during welding of interlocks, which will be described later. Fuse 1 that melts due to the operation of shot switch 18
5. Additionally fuse 15 is door 7
It is connected to the primary winding of the high-voltage transformer 9 through two interlock switches 16 and a relay 17 whose contacts open and close when the switch is opened and closed. Also relay 17
is turned on by a heating start signal and a heating completion signal input to the microcomputer (hereinafter referred to as microcomputer) 19 via the keyboard 13.
Turn off. Connected to both ends of the primary winding of the high-voltage transformer 9 are a short switch 18 that disables the entire circuit when the blow fan 6 and the aforementioned interlock 16 are welded together, and a lamp 20 that illuminates the inside of the heating chamber 4. ing. The other terminal of the power plug 14 is connected to the primary winding of the high voltage transformer 9. Microcomputer 1 by keyboard 13
A display tube 21 is connected to the microcomputer 19 in order to display the contents of commands inputted to the microcomputer 19 and to display a clock display.

The AC power applied to the high-voltage transformer 9 is stepped up by the high-voltage transformer 9 to become high-voltage power.The high-voltage power is converted into high-voltage DC power that is voltage-doubled and rectified by a voltage-double rectifier circuit composed of a high-voltage capacitor 10 and a high-voltage diode 22. Ru. The high-voltage DC power is supplied to the high-frequency oscillator 1 via a high-voltage switch 23 that opens and closes at certain intervals to vary the amount of high-frequency output. The voltage switch 23 is opened and closed by the microcomputer 1 using the keyboard 13.
Control is performed according to the output mode input to 9.
The high voltage DC power supplied to the high frequency oscillator 1 is converted into high frequency by processing the heater of the high frequency oscillator 1 by the heater winding 24 provided in the high voltage transformer 9, and is radiated from the antenna 3, as described above. Heat the food.

FIG. 4 is a structural diagram of the keyboard 13, which is composed of a display sheet 24 having a conductive material only for the keys on the back side, an insulating sheet 25, and a printed circuit board 26. A contact point is formed by sandwiching it between the two. Since the insulating sheet 25 has a square hole only in the key portion, the display sheet 24 and the printed circuit board 26
In between, a secret room is created for each part of the key.

As described above, if the room remains closed, the on-off operation of the high-frequency heater will be affected, and when the temperature rises, the air in the closed room expands, causing the display sheet 24 to swell.
To prevent this, the printed circuit board 26 is provided with an air vent hole 27 for each key. Figure 5 is an enlarged view of the display sheet 24.
An insulating sheet 25 is sandwiched between the key and the printed circuit board 26 to form a closed room in the key area, which is communicated with the outside through an air vent hole 27.

FIG. 6 shows a state in which the back plate of the present invention is removed, and there are six protrusions 30 on the periphery of the back plate 28 and one protrusion 30 in the center for venting air.
The air vent protrusion 30 is convex toward the keyboard 13 and has a height of 0.5 to 1.0 mm. Therefore, when the back plate 28 and the keyboard 13 are combined, a gap of 0.5 to 1.0 mm is formed between the keyboard 13 and the back plate 28. The reason why the air venting protrusion 30 is set to 1.0 mm or less is to prevent the key from becoming sticky when pressed.

By configuring as above, keyboard 1
When the 3 key is pressed, or when heat is applied and the temperature of the key area rises, air escapes from the aforementioned closed chamber of the key area through the air vent hole 27 of the keyboard 13 itself, and furthermore, the gap between the keyboard 13 and the back plate 28. More air escapes to the outside. Also, when you stop pressing the key, air enters the closed chamber of the key part, contrary to the above.

Therefore, it is not necessary to construct a different back plate for each keyboard as in the conventional case, and it is now possible to attach the same back plate 28 to the keyboards 13 having the same external shape. Also, there is no need to machine holes for air vents in the back plate, and there is no need to worry about rust in the machined parts.

As described above, according to the present invention, the following effects can be obtained.

(1) For keyboards with the same external shape, it is possible to share the back plate constructed to reinforce the keyboard.

(2) There is no need to drill holes in the back plate, there is no malfunction due to iron rust, etc., and it is possible to provide a highly reliable operating device for a high-frequency heater.

(3) Due to the operation of the high-frequency heater, the display surface of the keyboard will not bulge even when the temperature reaches high temperatures.

[Brief explanation of drawings]

Figure 1 is an external perspective view of the high-frequency heater, Figure 2 is a side sectional view of the heater, Figure 3 is a control circuit diagram of the heater, Figure 4 is an exploded perspective view of the keyboard of the heater, FIG. 5 is an enlarged perspective view of the main parts of the same keyboard, FIG. 6 is an exploded perspective view showing an operating device for a high-frequency heater which is an embodiment of the present invention, and FIG. 7 is an exploded perspective view showing an operating device for a conventional high-frequency heater. FIG. 11...Operation panel, 13...Keyboard, 2
7... Air vent hole, 28... Back plate, 30...
Air vent protrusion.

Claims (1)

[Claims] 1. A keyboard having an air vent hole on the rear surface is provided on the wall surface of an electrical component room containing a high frequency oscillator, a high voltage transformer, a blower fan, etc., and a metal back plate that isolates the electrical component room and the keyboard, and An operation device for a high-frequency heater, comprising: a protrusion formed around the back plate, a gap provided between the keyboard and the back plate, and an operation panel provided with ventilation between the gap and the outside.