JPS6149325A - 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. By the way, since the thermostat is mechanical, failures such as malfunction or seizure of contacts may occur, and there is a risk that the device may be burnt 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.

Figure 8 shows an example of an iron as an electrical 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 the heater 2 has a base 1 made of a metal such as aluminum. A thermostat 4 operated by a bimetal 3 is provided, and this thermostand 4
Thus, the surface temperature of the pace 1 is maintained at a set value.

Further, a temperature fuse 5 is installed 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 thermostand adjustment member. Moreover, FIG. 9 shows an electric circuit.

The temperature fuse 5 has a temperature sensing element υ made of a crystalline organic compound or an easily fusible metal sealed inside the casing, and when the temperature rises, 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 220° C. at most, and if a heat receiving relationship is directly established with the pace 1, there is no margin during normal use, and there is a problem that it may burn out prematurely. 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 that is difficult to receive the heat of the pace 1 directly. This arrangement of the temperature fuse 5 has poor heat receiving sensitivity, and the maximum temperature of the pace 1 when the temperature fuse 6 is activated becomes an abnormally high temperature, leading to melting of the pace 1, dielectric breakdown of the heater 2, and fire.

There was a risk of serious accidents such as electric shock.

In addition, 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, making it prone to 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-mentioned 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 the opening/closing member of the switch and fully supports the opening/closing member;
The heated part receives the thermally responsive member and has a heat conducting relationship with the thermally responsive member, the thermally responsive member is made of a material that melts when a predetermined temperature is reached, and has a slit in the pressing direction. It is configured as an over-temperature rise prevention device that responds sensitively to the over-temperature rise of the heated member and can open the switch to ensure safety.Furthermore, it stabilizes the melting point of the heat-responsive member and prevents malfunctions. It is possible to create a device with less

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

In the figure, reference numeral 8 denotes an iron plate, which is made of die-cast aluminum and has a seed-shaped heater 9 embedded therein, and is heated to a required temperature by the heater 9. A space 1 formed between the pace 8 and the cover 10
1 is provided with a thermostat 14 having contacts 13 that are opened and closed by a bimetal 12. Specifically, the thermostat 14 is supported by a mounting base 16 made of ceramic or the like fixed to a part of the cover 10, and the bimetal 12 is connected to the bimetal 12 by an adjustment member. The position of the can be adjusted.

One end of a first conductive plate 16 for a switch formed in a long 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. Second
conductive plates 18 are stacked on top of each other.

Contact points 19 and 20 are provided on corresponding surfaces near the tips of the first conductive plate 16 and the second conductive plate 18. The first conductive plate 16 has elasticity, and its tip is given a force toward the inside of the pace 8. Further, the second conductive plate 18 is also elastic and has a force in the direction of the first conductive plate 16, that is, it is given a force that tends to close the contacts 19 and 20.

An actuator 21 is provided inside the pace 8 and at a position corresponding to the tip of the first conductive plate 16. This actuator 21 is made of thermally insulating ceramic. Further, 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. It is becoming The protrusion 21c of the actuator 21 fits into a holding hole 22 formed on the inner surface of the pace 8, and a protrusion 23 formed on the edge of the holding hole 22 abuts the lower surface of the plate-shaped portion 21b of the actuator 21. , there is a heat transfer relationship between the pace 8 and the operating element 21. The diameter of the protruding seat 23 is smaller than the outer diameter of the plate-like portion 21b of the actuator 21. Further, the holding hole 22 has a slightly elongated shape in the longitudinal direction of the first conductive plate 16.

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 surround the pin 21d. This thermally responsive member 24 is formed into a cylindrical shape by bending the plate material shown in FIG. 3, and is made of a fusible alloy, so that it melts when the temperature rises excessively. Furthermore, the thermally responsive member 2
4 has a slit 24a in the pressing direction as shown in FIG. The pin 21d of the actuator 21 is connected to the first conductive plate 16
It passes through a hole 16a formed at the tip of the conductive plate 18, and its tip corresponds to the inner surface of the second conductive plate 18.

The tip of the first conductive plate 16 is connected to the thermally responsive member 2.
4 is pressurized in the direction of the base 8. The switch formed by the first and second conductors 16, 18 is connected in series to the thermostat 14, and these are inserted into the energizing circuit of the heater 9.

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 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.

In normal use of the iron, the heat moving member 24 maintains its original shape, and therefore is in the state shown in FIG. That is, 1st. contacts 19 of the second conductive plate 16.18;
20 is closed, and the energizing 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 line of the plate-like portion 21b of the actuator 21 maintain a distance A, and the line of the actuator 21
The tip of the pin 21d and the second conductive plate 18 maintain a distance B, and have a relationship of A>B. In addition, the heat of the base 8 is transferred from the protrusion A to the thermally responsive member 24 via the plate-shaped portion 21b of the actuator 21.
It is reported that.

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 pressing the thermally responsive member 24 is displaced in the direction of the base 8 by a distance A as shown in FIG. 7 before the support is lost. In response to this, the second isoelectric 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 no further displacement is possible. thwarted. Since the interval A) is B, the first. As the distance between the second conductive plates 16 and 18 increases, 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. As a result, reliable operation can be achieved and safety is improved. Further, the thermally responsive member 24 is received by the base 9, and has a good heat transfer relationship with the base 9 due to the pressurizing force, thereby ensuring the stress in the event of an excessive temperature rise. Further, the heat-responsive member 24 is quickly melted by pressurization, which contributes to rapid operation of the switch.

Since the heat-responsive member 24 has a sulin 24a in the pressurizing direction, the internal pressure does not increase in the pressurized state, that is, the liquid phase point etc. do not displace, and the base 8 does not rise excessively. The melting temperature remains almost constant over time, allowing accurate operation.

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.

Moreover, the base g 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, in the temperature overrise prevention device of the present invention, when a predetermined temperature is reached, the heat sensitive member melts and loses the supporting force of the pressurized switch member. Since the switch is configured to open, it operates without malfunction as an overtemperature rise prevention device, providing a highly safe and reliable device. Furthermore, since the heat-sensitive member has a slit in the direction of pressure, it relaxes internal stress and melts at a constant temperature, allowing accurate operation.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a main part of an iron equipped with an overtemperature rise prevention device according to an embodiment of the present invention, Fig. 2 is a top view of the thermally responsive member, Fig. 3 is an exploded view thereof, and Fig. 4 is A plan view of the thermostat and the temperature over-rise prevention device, FIG. 6 is a plan view of the temperature over-rise prevention device, FIG. 6 is a sectional view of the same, FIG. 7 is a sectional view of the same operating state, and FIG. 8 is a conventional temperature rise prevention device. The overheating prevention device is a sectional view of the iron, and FIG. 9 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 the switch, 19, 20...
...Contact, 21... Actuator, 24...
Thermal response member, 24a...Slit. Name of agent: Patent attorney Ken Nakao and 1 other person 1st
Figure 2 Figure 3 40L @4 Figure 5 Figure 6 Figure 7

Claims (2)

[Claims] (1) A switch of an energizing circuit, a thermally responsive member that is pressurized by the switching member of the switch and supports the switching member, and a heated member that receives the thermally responsive member and has a heat conducting relationship with the thermally responsive member. An overtemperature rise prevention device, comprising: a heat-responsive member made of a material that melts when a predetermined temperature is reached, and having a slit in a pressurizing direction. (2) The excessive temperature rise prevention device according to claim 1, wherein the thermally responsive member is formed in a cylindrical shape.