JPH0375199B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention eliminates malfunction by increasing the margin between the fuse blowing temperature and the fuse temperature during normal use, and also prevents the base surface temperature from rising excessively when the temperature fuse is activated. , which eliminates the deformation and melting of the base.

Traditionally, when using a temperature fuse in an iron,
In most cases, the installation location was limited to the space surrounded by the base and cover. For example, it was placed at the rear of the base or connected to the heater terminal. However, the maximum temperature of the base surface of an iron is usually around 200℃, and the temperature inside the space surrounded by the base and cover is close to the base surface temperature due to hot air, which is why the current temperature fuse In view of the fusing temperature range and the normal use heat resistance of the temperature fuse itself, it is actually desirable to install the fuse in a location where the temperature is lower than the inside of the cover. Specifically, the upper part of the cover,
The rear part of the cover may be considered, but if it is actually installed in these locations, the following problems will occur. In other words, assuming that the heel of the iron is in contact with the floor, the iron is in an upright position, and the thermostat contact is welded and the current is continuously energized,
The temperature of the base surface continues to rise, but the speed of heat transfer to the temperature fuse is delayed, and when the temperature fuse reaches the melting temperature, the base surface temperature rises too much, causing the base to deform or melt, creating a very dangerous situation. becomes. In order to prevent the temperature fuse from blowing out due to malfunction under normal usage conditions, the temperature at which the temperature fuse blows,
It is necessary to have a large margin, which is the difference between the maximum temperature rise of the fuse and taking into account product variations under normal usage conditions, and the installation location of the temperature fuse must be selected to satisfy this margin. In other words, a location as far away from the heater as possible is preferable. On the other hand, if the heater becomes continuously energized due to a failure of the thermostat or the like, it is better for the temperature fuse to blow out quickly, and therefore the closer to the heater the better the response. There is no installation location that satisfies both of these contradictory conditions, and conventionally, temperature fuses have not been used with sufficient margin.

In contrast, as described below, the present invention provides a sufficient margin between the fuse temperature during normal use and the blowout temperature, and also controls the temperature fuse in a responsive manner when the heater is continuously energized. activate it,
This eliminates deformation and melting of the base surface.

In Figures 1 to 3, 1 is a base having a heater 1', 2 is a cover installed on the base 1, and 3 is a base having a heater 1'.
is the heel part of the iron. The temperature fuse 4 is attached to the upper surface of the cover 2, and the temperature fuse 4 is covered with a heat-resistant electrically insulating tube 5 (for example, a silicone resin tube) to ensure electrical insulation from the cover 2. The temperature fuse 4 is fixed by welding a support fitting 6 to the cover 2 via an insulating tube 5. A lead wire 7 coming out of the temperature fuse 4 passes through a rear hole 9 of a heat insulating plate 8 and is connected to a terminal block 10. There is a hole 11 in the cover 2 in front of the temperature fuse.
is provided, one end of which is fixed to the base 1, and the other end of the bimetal 12 passes through the hole 11 to the cover 2.
It protrudes from the top of the iron, and maintains a certain distance from the temperature fuse 4 under normal operating temperature conditions of the iron. The upper part of the cover of the temperature fuse 4, lead wire 7, and bimetal 11 is surrounded by a rib 13 that is a part of the heat insulating plate 8, and is not subjected to any external force.

In the above configuration, the temperature fuse 4 is installed above the cover 2, and maintains a temperature with sufficient margin for the fusing temperature under normal ironing conditions. On the other hand, when the heater is continuously energized, the bimetal 12 fixed to the base 1 bends as the temperature of the base 1 rises, and when the base temperature far exceeds the normal operating temperature, it contacts the temperature fuse 4 and transfers the high temperature of the base surface to the bimetal 12. The temperature is transmitted to the temperature fuse 4 through the temperature fuse 4, and the temperature fuse 4 is fused to prevent the temperature from rising excessively. Therefore, without the bimetal 12, the base surface melted when the temperature fuse 4 was activated, whereas with the bimetal 1
2, it is possible to completely eliminate deformation of the base surface.

Figure 4 shows the use of bimetal as a thermal element.
A shape memory alloy 14 made of Ti-Ni alloy or the like is attached to the top surface of the cover. When the temperature of the base 1 rises abnormally, the state shown in FIG. It has the same functionality as . In addition to bimetals and shape memory alloys, various other types of thermosensitive elements can be considered.

As described above, the present invention includes a temperature fuse connected to a heater circuit and a thermally responsive element whose one end is attached to a base, and a gap is provided between the other end of the thermally responsive element and the temperature fuse. In addition, in response to an abnormal temperature rise in the base, the temperature fuse is displaced toward the temperature fuse and brought into contact with the temperature fuse, so that when the base temperature is normally controlled, the temperature fuse The temperature is maintained at a low temperature without being affected by the position of the iron or changes in the base temperature due to switching between steam and dry mode, and the difference between the melting temperature and the melting temperature is large, preventing malfunctions during use. If a malfunction occurs and the base temperature rises abnormally, the heat is quickly and accurately transferred to the temperature fuse by thermal conduction regardless of the iron's position, allowing it to reach the fusing temperature at once and shutting off the heater circuit. Therefore, malfunction of the temperature fuse during use can be prevented, and even in the event of an abnormality, the heater circuit can be safely shut off without overheating and damaging the handle or the like. As a result, not only are restrictions on selection of the operating temperature of the thermal fuse and its installation reduced, but also safety and reliability can be improved.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway sectional view of an iron showing an embodiment of the present invention, Fig. 2 is a perspective view of a temperature fuse installation part, Fig. 3 is a sectional view of the same, and Fig. 4 A and B are FIG. 7 is a sectional view showing another embodiment of the present invention before and after operation. 1...Base, 1'...Heater, 2...Temperature fuse, 11, 14...Thermosensitive element (bimetal, shape memory alloy).

Claims (1)

[Claims] 1. A base having a heater, a cover covering the upper surface of this base, a handle installed on this cover, a temperature fuse attached to the cover and connected to the circuit of the heater, and one end attached to the base. a thermosensitive element, the other end of the thermosensitive element is opposed to the temperature fuse with a gap therebetween, and the thermosensitive element is displaced toward the thermal sensitive element in response to an abnormal temperature rise of the base. An overheating prevention device for an iron, wherein the iron is brought into contact with the temperature fuse.