JPS6149327A - Temperature overrise preventing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an overtemperature rise prevention device which opens the electric circuit of an iron or other appliance when the temperature thereof rises to ensure safety.

2. Description of the Related Art Conventional Structures and Problems Generally, in electrical equipment, a thermostat having a bimetal as an operating element is used as a means for adjusting the temperature of the electrical equipment. However, since the thermostat is mechanical, failures such as malfunction or seizure of contacts may occur, and there is a danger that the device may burn out due to excessive temperature rise. As a means for preventing this excessive temperature rise, a temperature fuse is used, and when the temperature rises excessively, the temperature fuse blows out, for example, cutting off the heater circuit to ensure safety.

Fig. 6 shows an iron as an example of an electric device.A base 1 made of metal such as aluminum has a heater 2 built in to heat it, and a current-carrying circuit of this heater 2 is I'm having a hard time. Further, a temperature fuse S is provided in the current supply circuit of the heater 2 as a means for preventing excessive temperature rise. Note that 6 in the figure indicates a thermostat adjustment member. Moreover, FIG. 7 shows an electric circuit.

The temperature fuse 5 has a temperature sensing element made of a crystalline organic compound or an easily fusible metal sealed inside the casing, and when the temperature rises excessively, the temperature sensing element melts and opens an energizing circuit.

By the way, the melting point of the temperature sensing element in the temperature fuse 6 is about 22Q° C. at most, and if the base 1 is directly connected to heat reception, there is no margin during normal use, and there is a problem that premature breakage occurs. Therefore, in order to reduce malfunctions, it has been necessary to locate it in a position where there is a large degree of margin, that is, on the back side of the pace cover 7 or in a space where it is difficult to receive the heat of the base 1 directly. Temperature fuse 6 like this
This arrangement has poor heat receiving sensitivity, and the maximum temperature of the base 1 when the temperature fuse 6 is activated is abnormally high, which may lead to melting of the base 1, dielectric breakdown of the heater 2, fire, electric shock, or other serious accidents. was there. Further, in the case of an iron, there is a problem in that the temperature rise inside the iron differs depending on its use condition, that is, when it is placed horizontally and when it is placed upright, and it is likely to cause malfunctions such as premature cutting.

Purpose of the Invention The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide an over-temperature rise prevention device that promptly detects over-temperature rises in equipment and operates accurately to improve safety and reliability. be.

Structure of the Invention In order to achieve the above object, the overtemperature rise prevention device of the present invention includes a switch of an energized circuit, a thermally responsive member that is pressurized by an opening/closing member of the switch and supports the opening/closing member;
A heated member is provided which receives the thermally responsive member and has a heat conducting relationship with the thermally responsive member, and when the thermally responsive member reaches a predetermined temperature, it melts or collapses and loses the supporting force of the opening/closing member, causing the opening/closing member to be closed. The switch is configured to displace the member and open the switch, and a heat insulating member is provided between the thermally responsive member and the opening/closing member to prevent heat from escaping from the thermally responsive member to the opening/closing member;
This ensures the melting or welding operation of the thermally responsive member when the temperature rises excessively.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

In the figure, reference numeral 8 denotes the base of the iron, which is made of die-cast aluminum and has a sheath-shaped heater 9 embedded therein, so that the iron is heated to a required temperature by the heater 9. A space 1 formed between the base 8 and the cover 10
1 is equipped with a thermostat 14 having contacts 13 that are opened and closed by a bimetal 12. More specifically, it is supported by a mounting base 15 made of ceramic or the like fixed to a part of the cover 10, and the bimetal 12 is adjusted by an adjustment member. The position can be adjusted.

One end of a first conductive plate 16 for a switch formed in an elongated shape is fixed to the mounting base 15, and an insulating plate 17 is interposed on the upper surface of the first conductive plate 16 for a switch. the second of
conductive plates 18 are stacked on top of each other.

Contacts 19,20 are provided on the corresponding surfaces of the first conductive plate 16 and the second conductive plate 18 near their tips. The first conductive plate 16 has elasticity, and its tip portion is connected to the base 8.
I am given the power to turn inward. The second electrically conductive plate 18 is also elastic and has a force in the direction of the first electrically conductive plate 16, ie it is subjected to a force tending to close the contacts 19,20.

An actuator 21 is provided inside the base 8 and at a position corresponding to the tip of the first conductive plate 16 . This actuator 21 is made of heat-resistant and insulating ceramic. Moreover, this actuator 21 has a plate-like portion 21b having a recess 21a on the upper surface, a protrusion 21c protruding from the center of the lower surface of the plate-like portion 21b, and a bottle 21d protruding from the center of the upper surface of the plate-like portion 21b. The raised seat 23 contacts the lower surface of the plate-shaped portion 21b of the actuator 21, showing the heat transfer relationship between the base 8 and the actuator 21.

A cylindrical thermally responsive member 24 is provided on the upper surface of the plate-like portion 21b of the actuator 21 so as to cover the bottle 21d. An insulating plate 25 for heat insulation is provided between the thermally responsive member 24 and the first conductive plate 16. The thermally responsive member 24
is made of a fusible metal and is designed to melt due to excessive temperature rise.

Note that the thermally responsive member 24 may be made of thermoplastic alloy resin or a low melting point metal washer instead of the fusible alloy. The pin 21d of the actuator 21 is inserted into the hole 16a formed at the tip of the first conductive plate 16.
The tip thereof corresponds to the inner surface of the second conductive plate 18 . The tip of the first conductive plate 16 presses the thermally responsive member 24 in the direction of the base 8. Said 1st. The switches made by the second electrical conductors 16, 18 are connected in series with the thermostat 14, and these are connected to the heater 9.
is inserted into the current-carrying circuit.

Next, the operation of the overtemperature rise prevention device having the above structure will be explained. The thermally responsive member 24 is designed not to melt or soften at normal iron operating temperatures. For example, when using eutectic solder, the melting temperature is adjusted by changing the blending ratio of the materials to increase the margin.

□ Under normal use of the iron, the thermally responsive member 24 maintains its original shape, and therefore is in the state shown in FIG. 4. That is, 1st. The contacts 19.20 of the second conductive plate 16.18 are closed, and the energization circuit of the heater 9 is closed. The temperature is adjusted by opening and closing the thermostat 14. In this state, the first conductive plate 16 and the edge of the plate-like portion 21b of the actuator 21 maintain a distance A, and
The tip of the pin 21d of the actuator 21 and the second conductive plate 18 maintain a distance B, and have a relationship of A>B. Further, the heat of the base 8 is transmitted from the protrusion 23 to the thermally responsive member 24 via the plate-like portion 21b of the actuator 21.

If the thermostat 14 fails and its contacts remain closed, and the temperature of the base 8 becomes abnormally high, the thermally responsive member 24 will melt. Therefore, the tip of the first conductive plate 16 that presses the thermally responsive member 24 loses its support and is displaced by the distance A in the direction of the base 8 as shown in FIG. In response to this, the second conductive plate 18 also tries to displace, but since the tip position of the pin 21d of the actuator 21 does not change, the second conductive plate 18 is displaced by the distance B, and further displacement is prevented. be done. Since the interval A) is B, the first. When the spacing between the second conductive plates 16 and 18 is close to the same distance, the contacts 19 and 20 open to cut off the current to the heater 9 and ensure its safety.

The overtemperature rise prevention device of the above embodiment has a configuration in which the conductive plate 16 serving as a switch element pressurizes the thermally responsive member 24, and the thermally responsive member 24 melts or collapses to displace the conductive plate 16 and open the switch. This ensures reliable operation and improves safety. Still, the thermally responsive member 24 has a good heat transfer relationship with the pressurizing force base 9, and the response to an excessive temperature rise is ensured. Further, the heat-responsive member 24 is rapidly melted, melted, and deformed by pressurization, which contributes to rapid operation of the switch.

An insulating plate 25 is interposed between the thermally responsive member 24 and the conductive plate 16, so that the heat of the base 8 is transferred to the thermally responsive member 2.
4, the heat of the thermally responsive member 24 is transferred to the conductive plate 16.
that is, without escaping through the thermally responsive member 24.
The temperature rises to accurately follow the temperature rise of the base 8, and operations such as melting occur depending on the required temperature, improving the accuracy of the operation.

Further, the insulating plate 25 provides electrical insulation between the conductive plate 16 and the thermally responsive member 24, and also has the function of preventing electrical leakage to the base 8.

In the above embodiments, an iron is used as the device, but the device may be an electric heating device other than the iron, such as an electric cooker or an electric stove.

Further, the base 8 may be an electrically insulating material such as a cover other than a metal body.

Effects of the Invention As is clear from the description of the above embodiments, the overheat prevention device of the present invention melts or collapses the heat sensitive member when the temperature reaches a predetermined temperature, thereby reducing the supporting force of the switch member being pressurized. Since the device is configured to open the switch when the device is removed, it can operate as an overtemperature preventive device without malfunction, and can provide a highly safe and reliable device. In addition, the heat-sensitive member is pressed against the heated member such as the base by the switch member, and has a good heat-receiving relationship.Furthermore, the heat applied to the thermally-responsive member is difficult to escape due to the heat insulating material, and the thermally-responsive member is It can respond sensitively to excessive temperature rises and operate accurately.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a main part of an iron equipped with an overtemperature preventive device according to an embodiment of the present invention, Fig. 2 is a plan view of the thermostat and the overtemperature preventive device, and Fig. 3 is an overtemperature preventive device. 4 is a sectional view of the same, FIG. 5 is a sectional view of the same operating state, FIG. 6 is a sectional view of a conventional iron with an overheat prevention device, and FIG. 7 is its electric circuit diagram. . 8...Pace of iron (heated member), 9.
... Heater, 14 ... Thermostat,
16... First conductive plate of the switch, 18...
...Second conductive plate of switch, 19.20...
- Contact, 21... actuator, 24... thermally responsive member, 25... insulating plate. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

Claims (2)

[Claims] (1) A switch of an energizing circuit, a thermally responsive member that is pressurized by the opening/closing member of the switch and supports the opening/closing member, and a heated target that receives the thermally responsive member and has a heat conducting relationship with the thermally responsive member. An overtemperature rise prevention device comprising a member, the thermally responsive member being made of a material that melts or melts when a predetermined temperature is reached, and the opening/closing member being insulated by a heat insulator. (2) The overtemperature rise prevention device according to claim 1, wherein the opening/closing member is made of a conductive plate and the heat insulator is made of an insulator.