JPH0229300A - Safety device of electric iron - Google Patents

Abstract

PURPOSE:To cut-off power to a heater when an iron, is left for a fixed time or more under its self sustaining state so as to improve the safety of an electric iron by providing a control means which cuts off power to a heater circuit when either allowable horizontal halt time or allowable self sustaining time under its self sustaining state passes, and setting the allowable self sustaining time longer than the time span required for an iron base to reach its set temperature after the power is first applied. CONSTITUTION:When a time of duration, with an electric iron 19 left in its horizontal ironing position, reaches an allowable horizontal halt time TH, an H level signal from the first timer circuit 24 is applied to the base of a transistor 32 so that the transistor 32 becomes conductive, it and forcibly changes the base electric potential of a transistor 11 to an L level. Therefore, the transistor 11 comes in cut-off state regardless of the signal level output from a comparator circuit 7. As the result, a current flow to a heater 3 is forcibly cut off. Further, when the electric iron 19 is left in its self sustaining state and the time of duration reaches an allowable self sustaining time TV, the second timer circuit 25 is activated, and power to the heater 3 is forcibly cut-off.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides that when an electric iron is in a horizontally stopped state or in a freestanding state where the iron base is separated from the object to be ironed such as cloth for a certain allowable time, the heater is turned off. This invention relates to a safety device for an electric iron that shuts off electricity.

BACKGROUND OF THE INVENTION Electric irons typically incorporate temperature control devices to maintain a substantially constant temperature of the iron base in direct contact with the fabric being ironed. In such a temperature control device, a switching circuit such as a relay is inserted between, for example, a 100-volt AC power source and a heater attached to an iron base, and the temperature of the iron base is transferred to the iron base heated by the heater. A temperature detection element such as a thermistor is installed. The comparison circuit compares the temperature detected by this temperature detection element with the set temperature, and when the detected temperature rises above the set temperature, a circuit cutoff signal is sent to the switching circuit, and the detected temperature is set to the set temperature. When the voltage drops below , a circuit conduction signal is sent to the switching circuit. In this way, the temperature of the iron base is maintained at approximately the set temperature.

However, for example, if the user leaves the electric iron in a horizontal ironing position due to the ringing of the telephone or a visitor, or even if the electric iron is left standing on its own as shown in Figure 4, earthquakes may occur. There is a risk of a fire if the electric iron falls over for some reason.

In consideration of such cases, some electric irons have
Some iron handles are equipped with a switch mechanism in the grip section, so that the temperature control device operates only when the iron handle is being gripped.

(Problem to be Solved by the Invention) However, in the electric iron in which a switch mechanism is provided in the grip of the iron handle as described above, the electricity to the heater is immediately cut off as soon as the iron handle is removed. The heater is shut off even when the iron is standing on its own as shown in FIG. 4 and the cloth on the ironing board is being mended or turned inside out. Therefore, when the iron handle is grasped to resume ironing, there is a concern that the temperature of the iron base frequently falls below the set temperature. As a result, there was a risk that a good iron finish could not be obtained.

The present invention has been made based on the above circumstances, and by providing a state detection switch, it is possible to prevent the electric iron from being left in a horizontal ironing state for a certain period of time or longer, or to be left standing in a freestanding state for a certain period of time or more. Then,
An object of the present invention is to provide a safety device for an electric iron that can further improve the safety of the electric iron by cutting off power to a heater.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the safety device for an electric iron of the present invention distinguishes between a horizontal state and a freestanding state of an electric iron, and a horizontal reciprocating state during ironing. a state detection switch for detecting the condition, and a control means for cutting off the power to the heater circuit when the horizontal stop permissible time in the horizontal state or the self-sustaining permissible time in the self-supporting state has elapsed; The time is set to be longer than the time required for the temperature to rise to the set temperature after the power is turned on.

(Function) In the electric iron safety device configured as described above, the state detection switch detects the horizontal state, the self-supporting state, and the horizontal reciprocating state. Then, when the horizontal state detected by the state detection switch exceeds the permissible horizontal stop time, power to the heater circuit is cut off. Therefore, even if the iron is left unattended, the heater is automatically shut off.

Moreover, when the self-sustaining state detected by the state detection switch exceeds the self-sustaining allowable time, the power supply to the heater circuit is cut off. Therefore, even if the iron is left standing for a long time, the heater is automatically shut off.

Furthermore, the self-supporting allowable time is set to be longer than the time required for the temperature of the iron base to rise to the set temperature after power-on. Therefore, the heater circuit is not cut off while the temperature of the iron base rises to the set temperature after the power is turned on.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing a safety device for an electric iron according to an embodiment. In the figure, 1 is an AC power supply that supplies 100 volt AC power to this electric iron through an outlet or plug, for example, and this AC power supply 1 is connected to a heater circuit as a heater circuit installed across the iron base 2 shown in Figure 3. A heater 3 is connected via a contact 5 of a relay 4.

In the figure, 6 is a voltage terminal that supplies DC drive voltage VC to each electronic component that constitutes this circuit, and a comparison circuit 7 for temperature control of the iron base 2 is connected between this voltage terminal 6 and the ground. . This comparison circuit 7 includes a variable resistor 8 for temperature setting, a set temperature T5 from a thermistor 9 as a temperature detection element attached to the iron base 2, and a detected temperature T.
is input. The output terminal of the comparison circuit 7 is connected to the base of a transistor 11 connected between the voltage terminal 6 and ground via the drive coil 10 of the relay 4. Further, a state detection switch 13 is connected between the power supply terminal 6 and the ground via a resistor 12.

This state detection switch 13 is configured electronically as shown in FIG. 2, for example. That is, one electrode 14 is attached to the bottom of a bottomed cylindrical case 15 made of a conductive material, and the other electrode 16 is attached through a through hole bored at the opposite end of the case 15. ing. Note that an insulating material 17 is embedded between the electrode 16 and the through hole. Mercury 18 is sealed inside the cylindrical case 15 as shown in the figure. As shown in FIG.
As shown in the figure, an electrode 14 is fixed at a slight inclination so as to be positioned on the lower side, as shown in the figure, in an electronic component storage section 21 formed at the rear end.

Therefore, as shown in FIG. 3, if the electric iron 19 is in a horizontal stop state, such as when ironing,
Since the mercury 18 sealed in the case 15 is located on the electrode 14 side, the space between the electrodes 14 and 16 is open. on the other hand,
As shown in FIG. 4, when the iron base 2 is separated from the object to be ironed and the electric iron 19 stands on its own, the mercury 18 sealed in the case 15 rolls in the opposite direction and the electrode 1
Contact 6. As a result, conduction occurs between the electrodes 14 and 16. Furthermore, during the ironing operation,
Since the electric iron 19 reciprocates while maintaining the horizontal state shown in FIG. 3, the mercury 18 inside the case 15 rolls back and forth.

As a result, this state detection switch 13 repeats the conduction and cutoff states.

In FIG. 1, the electrode 14 of the state detection switch 13 is
It is connected to the base of a transistor 23 which is connected via a resistor 22 between the voltage terminal 6 and ground. Further, a first timer circuit 24 and a second timer circuit 25 are connected in series between the voltage terminal 6 and the ground.
4 is connected to the collector of the transistor 23, and the reset terminal R of the second timer circuit 25 is connected to the collector of the transistor 23.
is connected to the electrode 14 of the state detection switch 13.

The first timer circuit 24 is formed of, for example, a monostable circuit, and when an L-level reset signal is input to the reset terminal 1, the output terminal is output after the horizontal stop permissible time TH determined by the time constant of the resistor 26a1 and the capacitor 27a has elapsed. Outputs an H level signal from. Note that if the signal level of the reset terminal ball changes to H level before the horizontal stop permissible time TH ends, the duration time measured before the change is cleared, and when the reset terminal 1 becomes L level again, the horizontal stop permissible time is reset. Start timing TH. Similarly, in the second timer circuit 25, when an L level signal is input to the reset terminal 1, the output terminal outputs an
Outputs a level signal. The output terminals of the first and second timer circuits 24 and 25 are connected to the base of a transistor 32 connected between the voltage terminal 6 and ground through a resistor 31 via diodes 28 and 29 for backflow prevention and a resistor 30, respectively. It is connected to the. The collector of this transistor 32 is connected to the transistor 11 in the same way as the output terminal of the comparator circuit 7.
connected to the base of

Note that base resistors 33, 34° 35 are connected between the bases of each transistor 11, 23, 32 and ground, respectively, and a diode 36 is inserted between both terminals of the drive coil 10 of the relay 4. , the horizontal stop permissible time TH is the electric iron 19
This is the allowable time for keeping the electric iron 19 in a horizontal state and not moving it, so it is set to a time that will not burn the cloth even if the electric iron 19 is left on the cloth to be ironed. On the other hand, the allowable self-supporting time Tv is the allowable time when the electric iron 19 is freestanding as shown in FIG.
It is set to the initial temperature rise time T1 required for the electric iron 19 to rise to the set temperature Ts, and the maximum time required to fix or turn the cloth on the ironing board while the electric iron 19 is standing on its own.

With the electric iron safety device configured in this way, when the power is turned on, the temperature T of the iron base 2 has not reached the set temperature T set by the variable resistor 8, so the thermistor 9 has a large resistance value, and an H level output signal is applied from the comparator circuit 7 to the base of the transistor 11. On the other hand, when the power is turned on, the electric iron 19 is generally in an independent state as shown in FIG. 4, so the state detection switch 13 is in a conductive state. Therefore, since the potential of the electrode 14 is at the ground level, the reset terminal of the second timer circuit 25 goes to L level at the same time as the power is turned on, and starts counting the self-sustainable time Tv. Also,
Since the transistor 23 is not conductive, the reset terminal 1 of the first timer circuit 24 is at H level and does not start counting the allowable horizontal stop time TH. Since the output signals of the first and second timer circuits 24 and 25 are at L level, the transistor 32 is not conductive. Therefore, since the transistor 11 is made conductive by the H level signal from the comparison circuit 7, a drive current flows through the drive coil 10 of the relay 4 and the contact 5 is closed. When the contact 5 is closed, current flows from the AC power source 1 to the heater 3, and the iron base 2 is heated.

When the temperature T of the iron base 2 reaches the set temperature Ts after the initial temperature rise time T1 has elapsed since the power was turned on, the resistance value of the thermistor 9 decreases and the output signal of the comparison circuit 7 changes to L level. As a result, the transistor 11 is cut off, so the contact 5 of the relay 10 is opened, and the current supply to the heater 3 is cut off. In this way, the temperature T of the iron base 2 is maintained approximately at the set temperature Ts. Note that since the self-supporting allowable time Tv is set to a value longer than the initial temperature rise time T1 required for the temperature T of the iron base 2 to rise to the set temperature Ts, the transistor 32 becomes conductive during the temperature rise and the temperature rises to the heater 3. The current supply will not be cut off.

When the temperature T of the iron base 2 rises to the set temperature Ts and the user holds the electric iron 19 horizontally as shown in FIG. 3 in order to iron, the state detection switch 13 is opened. . Therefore, since the potential of the electrode 14 changes to H level, the second timer circuit 25
The reset terminal R of changes to H level and the duration time measured up to now is cleared. In addition, the transistor 23
Since the base of the transistor 23 changes to the H level, the transistor 23 becomes conductive, and the reset terminal page of the first timer circuit 24 changes to the L level. As a result, the first timer circuit 24 starts counting the allowable horizontal stop time Tc.

However, during the ironing operation, the electric iron 1.9 is repeatedly moved back and forth, so the mercury 18 sealed in the case 15 of the state detection switch 13 rolls back and forth. As a result, the state detection switch 13 repeatedly turns on and off in a short period of time, so the first and second timer circuits 2
4.25 is constantly cleared, and the measurement of horizontal stop permissible time T or stand-alone permissible time TV never ends. Therefore, since the transistor 32 is never conductive, the transistor 11 that operates the relay 4 is connected to the comparator circuit 7.
ON/OFF control is performed only by the output signal of In this way, during normal ironing work, the first and second timer circuits 24 and 25 do not operate, so the temperature T of the iron base 2 is always adjusted to the set temperature T5 by the comparator circuit 7.
will be maintained.

Next, if for some reason the electric iron 19 is left in the horizontal ironing state as shown in FIG. The H level signal from the circuit 24 is sent to the transistor 32.
Since the voltage is applied to the base of transistor 32, this transistor 32 becomes conductive, and the base potential of transistor 11 is forcibly changed to L level. Therefore, the transistor 11 is cut off regardless of the level of the signal output from the comparator circuit 7. As a result, power supply to the heater 3 is forcibly cut off.

Furthermore, when the electric iron 19 is left standing on its own as shown in FIG. Similarly, the power supply to the heater 3 is forcibly cut off.

In this way, even if the electric iron 19 is left in a horizontal ironing state due to a telephone ringing, a visitor, etc., the heater 3 is automatically shut off after the horizontal stop permissible time T has elapsed. Therefore, fire can be prevented and safety can be improved.

Furthermore, even if the electric iron 19 is left in a free-standing state as shown in FIG. Even if something falls down, there will be no fire, further improving safety.

Furthermore, during normal ironing work, the first and second timer circuits 24 and 25 do not operate, and the iron base 2 is always maintained at the set temperature Ts, so it is possible to obtain a good iron finish. be.

Furthermore, as mentioned above, the self-supporting allowable time Tv is set longer than the initial temperature rise time T, so after the power is turned on, the heater 3 is turned on before the temperature T of the iron base 2 rises to the set temperature T. Since it is never shut off, temperature can be controlled more reliably.

[Effects of the Invention] As explained above, according to the present invention, by providing a state detection switch, the electric iron can be left in a horizontal ironing state for a certain period of time or more, or can be left in a free standing state for a certain period of time or more. Then, the power to the heater is cut off.

Furthermore, the self-sustaining allowable time is set longer than the initial temperature rise time.

Therefore, the safety of the electric iron can be further improved, and since the heater is not cut off during the temperature rising process when the power is turned on, the temperature can be controlled more reliably.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a safety device for an electric iron according to an embodiment of the present invention, Fig. 2 is a sectional view showing a state detection switch used in the safety device, and Fig. 3 is a circuit diagram showing a state detection switch used in the safety device. FIG. 4 is a diagram showing the electric iron in a horizontal state, and FIG. 4 is a diagram showing the electric iron in a freestanding state. 1...AC power supply, 2...iron base, 3...
Heater, 4... Relay 7... Comparison circuit, 8...
Variable resistance, 9...Thermistor, 11, 23.32...
- Transistor, 13... State detection switch, 14.
16... Electrode, 15... Case, 18... Mercury,
19... Electric iron, 21... Electronic parts storage section,
24...First timer circuit, 25...Second timer circuit. Applicant's agent Patent attorney Takehiko Suzue Figure 4

Claims (1)

[Claims] A state detection switch that detects the horizontal state and freestanding state of the electric iron and the horizontal reciprocating state during ironing, and energizing the heater circuit when the horizontal stop permissible time in the horizontal state or the self-supporting permissible time in the self-supporting state elapses. A safety device for an electric iron, characterized in that the self-supporting allowable time is set to be longer than the time required for the temperature of the iron base to rise to the set temperature after power-on.