JPS6359360B2 - - Google Patents

Description

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

Conventionally, as a temperature display device for this type of appliance, for example, in the case of an iron, a thermo lamp is simply connected in parallel with a heater. Therefore, when a certain set temperature is determined and the power is turned on, the thermo lamp continues to light until the set point is reached, and when the set point is reached, the thermo switch is turned off, the heater is turned off, and the thermo lamp is also turned off at the same time. The fact that the temperature has risen to the set temperature can be known by turning off the indicator lamp. This situation will be explained with reference to FIG. When you turn on the power after setting it to a high temperature, the temperature will rise from the point of time zero, so
The heater current flows, and when it reaches point _A1 , it reaches the set temperature. As a result, the thermoswitch is turned off and the heater is turned off. At the same time, the thermo lamp also turned off, indicating that it had reached the set temperature. and the iron
A ₂ , A _{3 .} . . As time passes, the heater and thermo lamp turn on and off. Next, when the set temperature is changed to a lower temperature, the temperature stops decreasing at point _B and the heater turns on.
The thermo lamp also lights up. This time, when the thermo lamp lights up, I know that the set temperature has been reached.

As described above, in the case of the conventional example, it is troublesome to know the set temperature by turning on the thermo lamp and turning it off at other times. Furthermore, if you miss this ₁ point A and ₁ point B, the ₂ points A and ₂ points B will blink in the opposite direction, so
The drawback is that you cannot make a correct judgment unless you wait until A ₃ and B ₃ points. Moreover, if this lamp blinks,
It is unclear whether the flashing is within the set value permissible temperature or outside the permissible temperature. Furthermore, some fabrics have a narrow allowable temperature range, and there has never been a fabric that reliably indicates that the temperature is within a certain range.

Furthermore, there is no display at all when the temperature is cooled down after use, so you won't know if it has cooled down for storage, etc. unless you touch it with your finger or bring it close to your cheek, which can be dangerous. It was inconvenient to dispose of it.

The present invention solves these conventional problems, and embodiments will be described below with reference to the accompanying drawings. In FIG. 2, 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 addition, these power supplies 1 and 2 are rectified by a diode 5 and connected to a resistor 6 in order to obtain DC power for the electronic circuit.
The voltage is lowered by the smoothing capacitor 7 and becomes a DC power source. The temperature adjusting volume 8 is arranged so that a voltage corresponding to each temperature click point on the left can be obtained at its output terminal 9. If we set it to 140 degrees now, one 3 terminals of the comparison amplifier of the zero-volt switching circuit 10 consisting of an IC will be set at 140 degrees.
A voltage corresponding to is applied. A voltage correlated with the temperature determined by the ratio of the resistance of the thermistor 11 for temperature measurement and the resistance 11' is applied to the other four terminals of the comparison amplifier. When the measured 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. Then, when the heater of the iron is heated and the temperature rises, the resistance of the thermistor 11 becomes small, and the voltage at the 4 terminals of the circuit 10 becomes the same as the voltage at the 3 terminals, the gate pulse from the 6th terminal disappears and the element 3 is turned off. Temperature is controlled as described above. On the other hand, for the temperature display, the volume is 8.
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 display body (hereinafter referred to as
(referred to as LED) 15 lights up, and if the temperature fluctuates above or below LED 14 or LED 16
lights up. This means that 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, and a voltage higher than this voltage is applied to the terminal of the means 17. be done. That is, 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 lights up. A voltage lower than the set voltage by the voltage drop of the other Zener diode 13 is applied to the terminal of the means 18, and a voltage lower than this voltage is applied to the terminal of the means 18. That is, when the temperature of the thermistor 11 becomes low and its resistance becomes high, the output of the means 18 becomes H, and the LED 16 lights up. At this time, the cathode of the LED 16 is L, so it lights up. this
The reason why the output of the cathode of the LED 16, that is, the output of the means 19 is L, is that a voltage of a high value corresponding to a high temperature such as 140 °C is applied to the terminal of the means 19, whereas a voltage equivalent to 50 °C is applied to the terminal of the means 19. This is because it has been done. When this voltage falls below the voltage equivalent to 50° C. at the terminal of the means 19, the output of the means 19 becomes H, and the LED 23 lights up.

In this way, each LED lights up,
The constant voltage element, that is, the Zener diode 12,
If the voltage drop for one unit of LED 13 is equivalent to approximately 20℃, the lighting range of LED 15 will be ±20 of the set value.
This means that the temperature is within ℃. Also +10℃, -20
It can also be set to °C. In order to vary this voltage, if a variable resistor is connected in parallel to the Zener diodes 12 and 13 in a potentiometer style, it is also possible to individually set a variable temperature range above and below the set value. It is also possible to set the temperature to +0°C or -20°C by placing it only in the lower side. Note that 20 and 21 are Zener diodes 12,
This is a resistor connected in series with 13.

FIG. 3 shows another embodiment, in which the load heater 4 is switched on and off by a relay. The set voltage from the output terminal 9 of the volumetric volume 8 is connected to the terminal of the comparison amplification means 24 consisting of an IC, and the voltage from the thermistor 11 is connected to the terminal, and both inputs are compared. If it is low, the output of the comparison amplification means 24 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 11 decreases, the voltage at the terminal of the comparison amplification means 24 decreases, and the output of the comparison amplification means 24 becomes L. Therefore SCR
26, relay 27, and relay contact 3 are each turned off and heating stops. On the other hand, the temperature display is inputted from the output terminal 9 of the variable resistor to each comparison amplification means 17, 18, 19 via Zener diodes 12, 13, etc.
Depending on their output, LED14, 15, 16,
The fact that 23 is lit is the same as in FIG.

In this way, the present invention can detect that a variable set temperature is within a certain range of variation, or that it is above or below this temperature.
Furthermore, each display reliably indicates that the temperature is below about 50°C. In the case of an iron as a heating device, irons made of natural fibers such as cotton and linen generally require a slightly higher temperature, that is, a slightly wider range of temperature fluctuation than the appropriate temperature, but once the melting point is exceeded, the iron will melt. The appropriate temperature range for the chemical fibers worn is narrow. To meet these needs, there is a display that shows when the ironing temperature is within the appropriate range, a display that warns when the temperature is higher than the appropriate temperature, and a display that warns when the temperature at the start of ironing is insufficient and rises. An indicator that indicates that the ironing process is in progress or that the temperature has dropped due to some reason during the process, and a storage case that can be stored quickly to prevent burns from touching your fingertips or cheeks when leaving the iron to cool after ironing is finished. 50 to the extent that there is no fire or danger such as burning.
By providing four indicators to indicate that the temperature has fallen to 0.degree. C., each different stage will be reliably displayed. Therefore, the operator's judgment at each stage of ironing work, such as starting, during, and after finishing the ironing work,
This allows quick and accurate action, and allows comfortable ironing work without irritation.

[Brief explanation of the drawing]

FIG. 1 is a temperature characteristic diagram of an iron, FIG. 2 is a circuit diagram showing one embodiment of the present invention, and FIG. 3 is a circuit diagram showing another embodiment. 1, 2...AC power supply, 4...Heater, 14,1
5, 16, 23... display body, 17, 18, 19...
…comparative amplification means.

Claims (1)

[Claims] 1. Connect the display bodies that display the appropriate set temperature, high temperature that exceeds the above temperature, low temperature that does not reach the above temperature, temperature that is below the level that does not cause burns, fires, etc. in series to the power supply, and connect each intermediate connection. 1. A temperature display device for a heating appliance, characterized in that an output of a comparison amplification means inputting voltages corresponding to the respective temperatures is connected to a point.