JPH0616456Y2 - Overtemperature prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an overheat prevention device provided in a safety device of an electric heating appliance such as an electric blanket or an electric carpet.

Configuration of Conventional Example and Problems Thereof A conventional temperature rise prevention device will be described below. First
FIG. 1 is a circuit diagram of an electric blanket using a device for preventing excessive temperature rise common to the conventional example and the present invention.

FIG. 2 is a configuration diagram of a heater wire constituted by the heater 6, the temperature sensitive material 7, and the temperature detection wire 8.

In the normal state, when the power switch 2 of FIG. 1 is closed, the heater 6 of the electric blanket and the temperature control block 9 are energized by the commercial power source 1 through the temperature fuse 3 and the temperature control block 9. Material (eg plastic thermistor) 7,
A temperature signal is sent to the temperature control block 9 through the temperature detection line 8 and the heating element (hereinafter referred to as a resistance) 4, and when the temperature of the electric blanket is lower than the set temperature, the thyristor 11 is turned on by the trigger signal from the temperature control block 9. Then, the heater 6 raises the temperature of the electric blanket. When the temperature reaches the set temperature, the temperature signal causes no trigger signal from the temperature control block 9 to turn off the thyristor 11. The above operation is repeated to keep the temperature of the electric blanket at the set temperature.

Next, the operation in the case of abnormality will be described.

When the heater 6 is continuously energized for some reason, the temperature is abnormally high, the temperature sensitive material 7 is melted, short-circuits with the temperature detection wire 8 and a large current flows through the resistor 4, and the resistor 4 generates heat.

When the temperature control block 9 fails, the thyristor 10
Is triggered to turn on and a heating element (hereinafter referred to as resistance)
5 gets feverish.

Next, the operation of the conventional overheat prevention device after the resistance 4 or 5 generates heat will be described.

FIG. 3 and FIG. 4 are a side view and a plan view of a conventional overheat prevention device. When the resistor 4 or 5 generates heat, the heat sensitive plate 1 for efficiently conducting the heat to the junction 3a of the thermal fuse 3
Heat is conducted to the junction point 3a of the thermal fuse 3 via 3 or 14 and melts to act as a fuse to cut off all energization to prevent excessive temperature rise. Reference numeral 12 is an adiabatic cushioning material that insulates the printed circuit board 15 from heat so that the resistors 4 and 5 are uniformly in contact with the thermal fuse 3.

However, with the conventional configuration, if the blanket is not energized, the user may remove the lid of the controller and repair the fuse incompletely with wire or solder. Or even life threatens. Also, when the heating element and the thermal fuse are not connected in series, there is no heat conduction through the terminals, so it is simply a good conductor of heat (such as ceramic or cement).
In the case of a plurality of heating elements and a thermal fuse, the integrated one has a large heat capacity, and even if one heating element generates heat at a low temperature (for example, -10 ° C or less), the thermal fuse does not melt down. there were. Further, when an excessive current flows through the heating element, the heating element may be destroyed before the thermal fuse is blown, and the device may not function as an excessive temperature rise preventing device. Also, the mounting area of the printed circuit board was large when it was arranged in a horizontal or vertical row.

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and provides a thermal fuse that melts quickly and reliably before the heating element is destroyed. Moreover, the mounting area of the printed circuit board is reduced. Further, it prevents the user from making an incomplete repair when the temperature rises abnormally and the thermal fuse is blown.

According to the present invention, a plurality of heating elements are located in the lower part and one thermal fuse is located in the upper part, and the central portion of the heating element and the heat-sensitive part of the thermal fuse are substantially parallel to each other at substantially the same position and at substantially equal distances. The heat-dissipating conductors are arranged in a triangular shape and the heat-dissipating bodies are interposed between the heat-generating bodies and between the heat-generating bodies and the thermal fuses, and at least one corner of the heat-dissipating body is removed.

Description of Embodiments One embodiment of the present invention will be described.

5 to 7 are a front view, a plan view, and
It is a side view, and the thermal fuse 16 is positioned above the resistors 17 and 18, and the central portions of the resistors 17 and 18 and the heat-sensitive portion of the thermal fuse 16 are substantially parallel to each other at substantially the same position and equidistantly equilateral triangles or isosceles sides. The heat-conductive conductors 19 are arranged in a triangular shape and the heat-conductive conductors 19 are interposed between the heat-generating bodies and between the heat-generating bodies and the thermal fuses, and the corners 19a of the heat-conductive conductors 19 are removed.

The circuit used in this overheat prevention device is the one in which the thermal fuse 3 in FIG. 1 is replaced with 16 and the resistors 4 with 17 and 5 are replaced with 18, and the operation of the circuit is exactly the same as the conventional example. The description is omitted.

Next, the operation of the overheat prevention device after the resistors 17 and 18 generate heat will be described.

When the resistors 17 or 18 generate heat individually or simultaneously, the heat is transferred to the thermal fuse 16 through the good thermal conductor 19 and the thermal fuse 16 is melted to cut off all energization to prevent overheating. At this time, since the good thermal conductor 19 is wrapped, it is impossible to restore the thermal fuse from the outside. Also, the resistance 1
When 7 and 18 generate heat, the central part has the highest temperature, and the heat-sensitive parts of the thermal fuse 16 are located on the same position in parallel and substantially equidistant to each other. The position of the thermal fuse 16 is maximized, and one of the resistors 17 or 18 at low temperature blows exactly and surely even at the time of low heat generation. In addition, even when overloaded, resistance 1
The thermal fuse 16 is surely blown before the destruction of 7 or 18.

Further, as shown in FIGS. 8 to 10, the three resistors 21, 22, and 23 are placed at the bottom, and at the same position parallel to the center of the resistors,
The temperature fuses 20 may be arranged at substantially equal distances, and a good thermal conductor may be interposed in a triangular shape. Further, since it is formed in a triangular shape, it can be configured in three dimensions, and it is smaller in terms of mounting than it is configured in a vertical or horizontal plane.

Effect of the Invention In the device for preventing overheating of temperature of the present invention, a plurality of heating elements are located in the lower part and one thermal fuse is located in the upper part, and the central part of the heating element and the heat-sensitive part of the thermal fuse are substantially parallel. At least one corner of the good heat conductor is removed by arranging the good heat conductors between the heat generators and between the heat generators and between the heat generators as well as arranging them in a triangular shape at substantially equal distances from each other. Even if the body heats up, the thermal fuse will surely melt before the destruction of the heat generating body upon overload.
Further, even when the heat generating element generates a low amount of heat at a low temperature, the thermal fuse is quickly and surely blown. Further, the mounting area can be reduced and the mounting can be performed stably. Further, the heat capacity is reduced, and the thermal fuse is blown more quickly at low temperatures. In addition, it is possible to prevent abnormal temperature rise due to incomplete repair by the user, and prevent fire and burns.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an electric blanket using an overheat prevention device, FIG. 2 is a configuration diagram of the same heater wire, and FIGS. 3 and 4 are side views and plan views of a conventional overheat prevention device. 5 to 7 are front views, plan views and side views of an overheat prevention device according to one embodiment of the present invention, and FIGS. 8 to 10 are front views and plan views of other embodiments of the present invention. It is a side view. 16,20 ...... Thermal fuse, 17,18,21,2
2, 23 ... Heating element, 19, 24 ... Good thermal conductor.

Claims (1)

[Scope of utility model registration request] 1. A plurality of heating elements are located in the lower part and one thermal fuse is located in the upper part, and the central part of the heating element and the heat-sensitive part of the thermal fuse are substantially parallel to each other at substantially the same position, and are triangular at substantially equal distances. A device for preventing excessive temperature rise, which is arranged in a shape position, and in which a good thermal conductor is interposed between the heating element and the heating element and between the heating element and a thermal fuse, and at least one corner of the good thermal conductor is removed.