JPS6216680B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display device for a heating appliance such as an iron or an oven.

Generally, this type of appliance has a wide temperature control range.
For example, it is necessary to be able to design the temperature from 40℃ to 250℃ and set the temperature anywhere in between according to your preference. Conventionally, there has been no display that simply indicates that the set temperature has been reached. Furthermore, when a display body is provided, its temperature fluctuates up and down depending on the weight and weight of the load, how each part is attached, etc. On the other hand, in the case of ironing, there is an appropriate allowable range of temperature fluctuations depending on the type of cloth.

The present invention provides a device that can easily change the lighting temperature range of the display that displays the temperature fluctuation range having such various conditions as appropriate.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, voltages from AC power sources 1 and 2 are applied to a heater 4 via a bidirectional three-terminal controlled rectifier 3. In FIG. In order to obtain a DC power source for an electronic circuit, the AC power sources 1 and 2 are rectified by a diode 5, voltage is dropped by a resistor 6, and smoothed by a smoothing capacitor 7 to become a DC power source. The temperature adjustment volume 8 is designed so that voltages corresponding to each temperature click point on the left can be obtained at its output terminal 9.
Assuming that the temperature is set at 140℃, one of the comparison amplifiers in the zero-volt switching circuit 10 consisting of an IC,
The voltage is applied to the terminal. A voltage is applied to the other four terminals of the comparator amplifier, which is correlated with the temperature determined by the resistance change of the thermistor 11 for temperature measurement and the ratio to the resistor 11'. When the temperature is low, the resistance of the thermistor 11 is high, so the voltage at the four terminals is low. Therefore, the circuit 10 outputs a gate pulse from the 6th terminal, turns on the element 3 by zero-volt switching, and causes current to flow through the heater 4. When it is heated and the temperature rises, the resistance of the thermistor 11 becomes smaller and the voltage at the 4th terminal of the circuit 10 becomes the same as the 3rd terminal, the gate pulse from the 6th terminal disappears and the element 3
It becomes OFF.

The temperature is controlled as described above, but the temperature is displayed using the light emitting diode only during temperature fluctuations corresponding to the voltage drop of the two Zener diodes 12 and 13 connected to the output terminal 9 of the volume control 8. indicator (hereinafter referred to as LED) 15 lights up, and if the temperature fluctuates above or below this, LED 1
4 or LED16 lights up. This means that if a voltage higher than the voltage drop of the Zener diode 12 than the set voltage of the regulator 8 is applied to the + input terminal of the comparison amplification means 17 made of an IC, a voltage higher than this voltage is applied to one terminal of the means 17. is applied to
In other words, when the temperature reaches such a high temperature that the resistance of the thermistor 11 becomes low, the output of the means 17 becomes L, and the LED
14 is lit. Means 18 lowers the voltage lower than the set voltage by the voltage drop of the other Zener diode 13.
In addition to the + terminal of , a voltage lower than this voltage is applied to the - terminal of the means 18 . In other words, when the temperature of the thermistor 11 becomes low and the resistance increases, the means 1
The output of 8 becomes H, and the LED 16 lights up. At this time, the cathode of the LED 16 is L, so it lights up. The reason why the cathode of this LED 16, that is, the output of the means 19 is L, is that the output of the means 19 is 50°C.
The negative terminal has a voltage of 140
This is because a voltage of a high value corresponding to a high temperature such as ℃ is applied. If this is lower than the voltage equivalent to 50℃ of the + terminal of means 19, means 1
The output of 9 becomes H, and the LED 23 lights up. Each LED lights up in this way, but if we set the voltage drop for one of the constant voltage elements, that is, the Zener diodes 12 and 13, to a voltage equivalent to about 20°C, the lighting range of the LED 15 will be within the set value ± This means the temperature is within 20℃. Moreover, it can also be set to +10°C or -20°C. In order to make this voltage variable, if a variable resistor is connected in parallel to the Zener diodes 12 and 13 in a potentiometer type, it is also possible to individually set the temperature above and below the set value to a variable range. It is also possible to set the temperature to +0°C and -20°C by placing only the lower side.

FIG. 2 shows another embodiment, in which the load heater 4 is switched on and off by a relay. The voltage from the thermistor 11 is connected to the + terminal of the set voltage means 24 from the output terminal 9 of the volume 8, and the voltage from the thermistor 11 is connected to the - terminal. The output becomes H, turns on the SCR 26 through the resistor 25, causes current to flow through the relay coil 27, closes the contact 3, and causes the heater current to flow. When the temperature is increased, the resistance of the thermistor decreases, the voltage at the negative terminal of the means 24 decreases, and the output of the means 25 becomes L. Therefore, the SCR 26, relay 27, and relay contact 3 are each turned off, and heating stops. On the other hand, the temperature display is the output terminal 9 of the variable resistor.
The signal is then inputted to each comparative amplification means 17, 18, 19 via Zener diodes 12, 13, etc., and LEDs 14, 15, 16, 23 are lit by their outputs. And LED15 that displays the set temperature
The Zener diodes 12 and 13 turn on the LED when the temperature is within a certain range, the LED 14 lights up when the temperature exceeds that range, and the LED 16 lights up when the temperature is insufficient. Display that it is not.

3 and 4 show still other embodiments. First,
In the case of Figure 2, one specialized LED 23 was added and turned on to notify when the temperature has cooled to about 50 degrees Celsius, which does not cause burns. Figures 3 and 4 show this 50℃
As a way to notify that the temperature has cooled to a certain degree, LED 16 is used to indicate that the temperature has fallen below the appropriate range.
This is a circuit that attempts to notify by blinking.

To explain only the main points, that is, in FIG. 3, the output of the means 17 is H and the output of the means 18 is L during the appropriate temperature range, so the LED 15 lights up. This lighting temperature range is zener diode 12,
As mentioned above, it is determined by the voltage drop of 13. When the temperature falls below that range, the output of the means 18 becomes H. On the other hand, until means 19 reaches around 50℃,
Since the - terminal to which the output from the thermistor 11 is connected is H compared to the + terminal, the output is L. Therefore, the + of the connected means 20 of the output of this means 19
Since the terminal is L, its output is L. accordingly
The anode of the LED 16 is H, and the cathode is L, so it lights up.As it gradually cools down to about 50 degrees Celsius, the voltage from the thermistor 9 connected to the - terminal of means 19 decreases, and when it falls below the + terminal, means 1
9 becomes H, the + terminal of means 20 becomes H, and means 20 enters an oscillation state as a multivibrator. In other words, the output of the means 20 changes from H to L at a constant cycle, and the LED 16 blinks. Therefore, while it is not blinking, the temperature is above 50℃, which is still below the appropriate temperature range, and when it is blinking, it is indicating that the temperature is below 50℃, meaning that one LED serves as two displays.

Figure 4 shows the means 20 for blinking this LED 16.
It is connected in parallel with LED16. In Figure 3, there is a loss because the LED 16 is connected in series and the lighting current is always flowing, but in Figure 4, if it does not blink at 50°C or higher, the oscillation will stop, so the output will be H.
There is no extra loss in the LED circuit, which is unrelated to the LED16 circuit. When the temperature drops below 50°C, the output of the means 19 changes to H, and the - terminal of the means 20, which had been held at L until now, is no longer held down.
0 oscillates as a multivibrator, and the output changes from H to L at a constant cycle, bypassing the current of LED 16 or not.
LED16 blinks. In addition, means 17 and 18 including Zener diodes 12 and 13, LED 14,
15 operates in the same manner as in FIG. 3, FIG. 1, etc., and its display temperature range can be changed by a Zener diode. In addition, in Figures 3 and 4, 21, 2
2, 26 are resistors, 25 are capacitors, 27, 28
is a diode.

Generally speaking, when ironing natural fibers such as cotton and linen, the temperature may be slightly higher, or the range of temperature fluctuation may be slightly larger than the appropriate temperature, but for synthetic fibers, the range of fluctuation must be narrowed to ensure that the temperature does not melt. If it exceeds the tying point, it will fuse and be bad. Therefore, since it is necessary to display a narrow temperature fluctuation range, it is preferable to use a low-temperature Zener diode.

Furthermore, even irons with the same performance have different temperature fluctuation ranges depending on where the thermistor is installed. In other words, the range of fluctuation is small near the heater, and increases when it is placed near the cloth load, that is, at a location farther from the heater. Since the temperature should be measured as close to the cloth as possible, the range of fluctuation will be large. Therefore, it is better to use a Zener diode with a high voltage in this case.

Furthermore, when a load is applied from no load, the temperature fluctuation tends to spread downward, so if you want to match the actual situation of the iron, even if the high end of the set temperature center is +5°C, the low end is -15°C. It is also necessary to provide a difference between the upper and lower sides, in which case Zener diodes with different voltages on the upper and lower sides will be used.

In this way, if constant voltage elements with different voltages are required, a volume may be used. Alternatively, the volume may be changed as needed.

The temperature display width will be decided by comprehensively considering each of the above conditions, but as described above, the present invention can satisfy various conditions, such as reducing the amount of fabric damage, It is possible to provide an easy-to-use device with good temperature display performance, such as the display not blinking due to slight temperature fluctuations.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention;
FIGS. 2 to 4 are circuit diagrams showing other embodiments. 1, 2...AC power supply, 4...Heater, 14,1
5, 16, 23...Display body.

Claims (1)

[Claims] 1. A temperature measurement means, a comparison amplification means for comparing a voltage corresponding to the temperature detected by the temperature measurement means and a voltage corresponding to a variable set temperature set by the temperature regulator, and a comparison amplification means that blinks and sets the temperature. It is characterized by having a display body that notifies the temperature, and a means for adding or subtracting a voltage corresponding to the temperature of the lighting expansion range to or from the variable setting voltage in order to widen the lighting temperature range of the display body. Temperature display device for heating equipment.