JPH0490797A - Iron - Google Patents

Abstract

PURPOSE:To detect the closed state of a relay contact due to fusion-welding or the like, and open the relay contact, and prevent abnormal heating previously from being generated by setting a means for generating the ON/OFF signal of a relay by specified frequency, when the temperature of a base is tuned into a specified temperature higher than a normal temperature. CONSTITUTION:When an abnormal state is generated on a relay contact 3 at the time point of a time (c) and the relay contact 3 is kept closed regardless of generating the output of OFF-signal from output (PO1), a heater 1 is continuously electrified and the temperature of a base is continuously heightened exceeding a set temperature. Then, it is discriminated by, a micro-computer 10 whether the base temperature taken from input(A/D) exceeds a specified temperature T (225 deg.C) set higher than the highest temperature (220 deg.C) which can be set or not and when it exceeds the temperature T, at the time point of a time (d), an internal releasing signal generating means is worked, and from the output (PO1), the output of releasing signal (ON-signal (0.4 second) and OFF-signal (0.6 second are alternately generated every five times) is generated, and oscillation is applied to the relay contact 3. By the oscillation, the contact attached due to fusion-welding or the like is separated from, and electrification to the heater 1 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an iron that prevents abnormal heating of the base due to relay welding or the like.

(b) Conventional technology In irons in which power is turned on and off to the heater through one loop, the surface of the relay contact becomes rough due to long-term use, resulting in poor response from the closed relay contact to the open state. In the worst case, the contacts may become welded.

When the iron contacts become welded, the heater continues to be energized and the temperature of the base becomes abnormally high, causing problems such as burning the clothes inside the iron and deforming the iron's components due to heat.

To solve this problem, Japanese Patent Application Laid-Open No. 61-263495 uses a method of notifying the user of the abnormal condition using a lamp, buzzer, etc. when the base temperature becomes abnormally high.

However, in the above method, when the user is away from the iron, the base continues to be abnormally heated, causing problems such as thermal deformation of various parts of the iron and the occurrence of a fire.

(c) Problems to be Solved by the Invention The present invention has been made in consideration of the above points, and detects the state in which the relay contact remains closed due to welding, etc., and opens the relay contact to prevent abnormal heating. The challenge is to prevent this from happening.

(d) Means for Solving the Problems The present invention is provided with means for generating relay ON/OFF signals a predetermined number of times when the temperature of the base reaches a predetermined temperature higher than the normal temperature range. .

Further, when the relay off signal is output for a predetermined period of time, means is provided for generating a relay on/off signal a predetermined number of times.

(e) If the working relay contact remains closed due to mechanical causes such as welding, the heater is continuously energized and the base temperature rises above the normal temperature. This temperature rise can be detected using existing temperature detection means.
Alternatively, by detecting it using a timer and applying an on/off signal to the relay several times, mechanical vibration is generated in the loop contact, the welded part or mechanical locking part is separated, and the relay contact opens.

(F) Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. (1
) is the heater that heats the base, (2) is the relay that opens and closes the relay contact (3) connected in series with the heater (1).
4) is a relay drive circuit consisting of a transistor (5) and a resistor (6), (7) is a temperature detection circuit consisting of a thermistor (8) and a resistor (9) that detects the temperature of the base, (1)
0) is a one-chip microcomputer (hereinafter referred to as microcomputer) with a built-in processing program, which constitutes the control means.

The microcomputer (10) inputs the output of the temperature detection circuit (7) (
A/D) to obtain a digital temperature signal, and a drive signal (on/off signal) for opening/closing the relay contact (3) is output to the drive circuit (P O1).
4) Output. (11) is a switch for temperature setting,
It is connected to the input (pH) of the microcomputer (10). (
12) is a temperature indicator with multiple LEDs (a), (b)...
The LEDs (a), (b), etc. are connected to the outputs (PO2) to (PO5) of the microcomputer (10). (13) is a power supply circuit that supplies DC power to each part, (
14) is a temperature fuse located near the base.

Next, the operation of the above configuration will be explained with reference to FIG. Here, at the time of (a), set the temperature setting switch (1).
1) is pressed to set the set temperature to ``High J (200℃).The microcontroller (10) compares the base temperature taken in from the input (A/D) with the set temperature, and determines the base temperature. Since it is low, an on signal is output from the output (POI).The on signal causes the relay drive circuit (4) to drive the relay (2), the relay contact (3) closes, and the heater (1) is energized.

Then, when the base temperature rises and exceeds the set temperature,
At the point in time (b), the microcomputer (10) outputs an off signal from the output (POl). This off signal causes the loop contact (
3) is opened and power supply to the heater (1) is stopped. Thereafter, the above operation is repeated to maintain the temperature of the base at the set temperature.

Here, at point (c), an abnormality occurs in the relay contact (3),
If the relay contact (3) remains closed despite outputting an off signal from the output (POI), the heater (1) continues to be energized and the base temperature exceeds the set temperature. Continue to rise. During this time, microcontroller (10)
detects whether the base temperature taken in from the input (A/D) exceeds a predetermined temperature T (225°C) that is higher than the highest temperature that can be set (200°C “high”), and When the temperature exceeds T, the internal release signal generation means is activated at the point (d), and the release signal (ON signal (0, 4 seconds) and OFF signal (0, 6 seconds) is alternately output from the output (POI). 5 times) to give vibration to the relay contact (3). Due to this vibration, the contacts that are stuck due to welding or the like are separated, the power supply to the heater (1) is stopped, the temperature of the base is lowered, and it is possible to prevent burnt clothes and fires. Here, the predetermined temperature T is the temperature fuse (1
The temperature is set lower than the operating temperature in 4).

Note that the predetermined temperature T may be constant as described above, but may be changed depending on the set temperature. For example, “High J (20
When set to 0°C, T is 225°C; when set to Medium J (150°C), T is 175°C; when set to Low J (100°C), T is set to 225°C;
If the temperature is set to 125° C., as the set temperature becomes lower, the welding release operation timing when the relay contacts become welded can be brought forward, and damage caused by abnormal heating can be reduced.

Next, other embodiments will be described. In the above example,
Although welding of the relay contact (3) was detected by the temperature of the base, it can also be detected by time as described below. That is, when the relay contact (3) is welded, the temperature of the base rises above the set temperature, so the relay off signal is continuously output, but the relay on signal is not output. Therefore, a timer is provided to time the output interval of the ON signal of the relay, and when this timer measures a time set longer than the normal interval, welding of the relay contact (3) can be detected.

To explain specifically, in the circuit shown in Figure 1, the internal timer (hard or software type) of the microcomputer (10)
The above-mentioned timekeeping means is constructed using the following.

This timer is reset each time the relay's ON signal is switched to an OFF signal, and is set to start timekeeping at the same time. Then, the microcomputer (10) determines that the time measured by this timing means is a predetermined time t (120 seconds) that is longer than the normal interval (about 80 seconds) from one turn on of the relay (2) to the next turn on. A part of the processing program has been changed in advance so that when it exceeds the limit, the internal release signal generating means is operated as in the above embodiment, and a release signal is output from the output (POI). Therefore, up to the point (c) in FIG. 3, the timing means does not measure time until time t, but even though the relay off signal is output at the point (c), the relay contact (3) Assuming that it remains closed, at point (2) when the timer measures time t, the microcomputer (10) outputs a release signal and applies vibration to the relay contact (3) to prevent welding of the relay contact. Execute the release.

(G) Effects of the Invention As described above, the present invention provides the following advantages: when the temperature of the base reaches a predetermined temperature higher than the normal temperature range, or when the interval at which the ON signal of the relay switches to the OFF signal exceeds a predetermined time. When
By providing a means to output relay on/off signals a predetermined number of times, it is possible to detect and release welding of relay contacts with a simple configuration, and prevent burning of clothing and fires caused by abnormal heating of the base. can be prevented from occurring.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2(a)
is the relay contact opening/closing timing diagram of the same example, the same figure (b)
3(c) is a temperature characteristic diagram of the base, FIG. 3(a) is a relay contact opening/closing timing diagram of another embodiment, FIG. 3(b) is a relay drive signal waveform diagram, figure(
C) is a temperature characteristic diagram of the base. (1)...Heater, (2)...Relay, (7)...
- Temperature detection means, (10)... microcomputer. Applicant Sanyo Electric Co., Ltd. 1 other agent Patent attorney Takuji Nishino (2 others) Figure 3 (a) (D) Figure 2 (a) (c) (d) Rin Procedural amendment (method) % Formula % Sanyo Electric Co., Ltd. Representative Kan Iue 4, Agent Address 2-1-8 Keihan Hondori, Moriguchi City Connected to Nidenkatsu (Higashiya) 837-6239 Chigen 1! Date of amendment order (shipment date) (C) (=) Column 6, Brief explanation of drawings of the specification subject to amendment 7, Statement of contents of amendment, page 9, line 13 ~ Line 19 “Figure 2 (a) is ~
It is a diagram. , is corrected as follows: ``Figure 2 shows various characteristic diagrams in an embodiment of the present invention, and Figure 3 shows various characteristic diagrams in another embodiment of the present invention.''

Claims (2)

[Claims] (1) A heater that heats the base, a temperature detection means that detects the temperature of the base, a relay that turns on and off the power to the heater, and a temperature of the base that is set to a desired temperature based on the output of the temperature detection means. control means for controlling on/off of the relay to maintain the temperature of the base; and release signal generation means for generating an on/off signal for the relay a predetermined number of times; The iron is characterized in that the release signal generating means is operated when the temperature reaches a predetermined high temperature. (2) A heater that heats the base, a temperature detection means that detects the temperature of the base, a relay that turns on and off electricity to the heater, and a temperature of the base that is set to a desired temperature based on the output of the temperature detection means. control means for controlling on/off of the relay in order to maintain the relay; release signal generation means for generating an on/off signal for the relay a predetermined number of times; 1. An iron comprising: a timer for starting timekeeping after a predetermined period of time, and wherein the release signal generating means operates when the timer measures a predetermined time.