JPH05135850A - Safety device for electric carpet and the like - Google Patents

Abstract

PURPOSE:To provide a safety device for an electric carpet furnished with a safety means which suspends heating with an electric circuit cut-off when heat is generated beyond a specified temperature in a control unit for the electric carpet and the like. CONSTITUTION:In a heating cloth such as an electric carpet and the like, there is provided a safety circuit which cuts off energizing a heating wire with a thermal fuse fused, when the heating cloth in which a heating wire is laid, is heated abnormally beyond a specified temperature, a heating resistor arranged close to the thermal fuse is heated with eddy current sent therein. A thermal conduction plate 7 is installed on a thermal fuse fusing element 5 with which the thermal fuse and the heating resistor are integrally molded, so that it is then interposed between a printed circuit substrate 2 in which the thermal fuse fusing element 5 is incorporated, and a control unit case 3. By this constitution, when any part in the printed circuit substrate 2 is abnormally heated beyond a specified temperature, the temperature is transmitted to the thermal fuse fusing element 5 from the heat conduction plate 7, so that the thermal fuse is fused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for an electric carpet or the like for stopping safety when abnormal heat is generated in a controller of the electric carpet or the like for safety.

[0002]

2. Description of the Related Art Electric carpets, electric blankets, electric sheets, etc. are known as heating cloths. Here, a conventional example of electric carpets will be described with reference to the accompanying drawings.
As shown in FIG. 4, the electric carpet 20 includes a carpet body 21 in which a heat generating cord 26 (solid line) and a temperature detecting cord 27 (dotted line) are laid between a front cloth 24 and a back cloth 25, and the carpet body 21. And a controller 22 provided at an end of the controller 22, and a temperature control circuit, a safety circuit, and the like are arranged in the controller 22. As shown in FIG. 5, the heating cord 26 has a heating wire 29 wound around a winding core 28 covered with a heat sensitive layer 30 made of nylon or the like, and a short-circuit wire 31 wound around and covered with an insulating jacket 32. It has a structure. In the electric carpet 20 of this example, the carpet body 21 is divided into two right and left surfaces, and the heating cords 26 are separately laid so that each surface can be heated individually or simultaneously. For heating cloths such as electric carpets, safety devices are provided to prevent accidents in the event of a failure or incorrect use. FIG. 6 shows an electric circuit diagram of the electric carpet 20, which comprises a heating circuit, a temperature control circuit and a safety circuit.

In FIG. 6, when the carpet body 21 is locally kept warm or is externally heated, the heating cord 26 locally abnormally generates heat, and as a result, the impedance of the heat sensitive layer 30 changes or the fuse melts, so that the heating wire 29 is short-circuited. A current flows through 31 to heat the heating resistor R1 connected to the short-circuit wire 31. The heat generating resistor R1 is arranged in the vicinity of the temperature fuse 10 connected in series to the power supply circuit, and the heat generation melts the temperature fuse 10 to cut off the power supply circuit and stop energization. Further, when there is overheat exceeding the control temperature due to the disconnection of the relay 34 for controlling the temperature of the heating wire 29 by controlling the opening / closing of the relay contact 34a or the welding of the relay contact 34a, the temperature is detected by the temperature detection code 27. Is detected by the temperature control circuit 38 and the gate of the SCR 35 is opened to cause an electric current to flow through the heating resistor R2 arranged in the vicinity of the thermal fuse 10 to generate heat, and the thermal fuse 10 is blown to cut off the power supply circuit. .. As shown in FIGS. 7 and 8, the safety means for shutting off the power circuit for fusing the thermal fuse 10 configured as described above with the heating resistor R1 or R2 is as shown in FIGS.
1 and R2 are integrally molded to form a thermal fuse blowing element 5, which is mounted on a printed circuit board 37 arranged in the controller 22. FIG. 7 is a plan view of the thermal fuse fusing element 5, in which the heating resistors R1 and R2 are arranged in close proximity on both sides of the thermal fuse 10 and are molded by a ceramic or the like to be integrated and lead wires are drawn out. Has been. This temperature fuse blowing element 5
Are arranged on a printed circuit board 37 arranged in the case 23 of the controller 22 as shown in FIG.

[0004]

With respect to abnormal heat generation on the carpet body 21 side of an electric carpet or the like, the safety circuit is provided as described above, and accidents such as ignition can be prevented. However, appropriate safety measures have not been taken against abnormal heat generation due to component failure, connection failure, etc. in the safety control controller. In addition, it is desirable that the electric carpet laid on the floor surface has no protruding portion, and thus the controller portion, which is the only protruding portion, is formed as thin as possible. Therefore, the heat generated inside the controller case is likely to affect the discoloration and deformation of the controller case,
The floor surface on which the controller is located may also be affected by discoloration due to heat generation. In view of the above problems, the present invention provides a safety device for an electric carpet, which is provided with a safety means for shutting off the heat by shutting off the power supply circuit when a heat generation above a predetermined temperature occurs in a controller such as an electric carpet. The purpose is to do.

[0005]

In order to achieve the above object, the means adopted by the present invention is such that a heating wire controlled by a control circuit provided on a printed circuit board is connected to a power supply circuit via a temperature fuse. In a safety device such as an electric carpet, the printed circuit board and the thermal fuse are directly or indirectly connected to each other via a heat conduction plate. It

[0006]

In the electric carpet or the like, the temperature of the heating wire is controlled by controlling the power distribution to the heating wire, and a safety device is provided to prevent an accident in the event of a failure or incorrect usage. That is, when abnormal heat is generated in the carpet body on which the heating wire is laid, control is performed to blow out the thermal fuse connected in series to the heating wire to cut off the power supply to the heating wire. The temperature control and safety control circuits and the temperature fuse are provided on a printed circuit board in the controller, and the printed circuit board and the temperature fuse are thermally connected to each other via a heat conduction plate to print. When abnormal heat generation occurs on the circuit board, the heat is conducted from the heat conduction plate to the thermal fuse and melts the thermal fuse. Therefore, the temperature fuse as a safety device at the time of abnormal heat generation on the carpet side also operates as a safety device at the time of abnormal heat generation on the controller side, and it is possible to provide a more complete safety device for an electric carpet or the like. ..

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention. still,
The following examples are examples of embodying the present invention and do not limit the technical scope of the present invention. Figure 1
Is a cross-sectional view of the required part of the controller in the electric carpet,
FIG. 2 is a partial cross-sectional view showing the structure of the heat conduction plate, and FIG. 3 is a partial plan view of the heat conduction plate on the metal layer side. The electric carpet 9 of the present embodiment has the same structure as the electric carpet 20 of the conventional example except for the internal structure of the controller 1. FIGS. 4 to 7 are common to those of the conventional electric carpet. Together with
5 to 7 have a common configuration, the description thereof will be omitted.
In FIG. 1, an opening 6 is provided at a mounting position of the thermal fuse blowing element 5 of the printed circuit board 2 housed in the controller case 3, and the thermal fuse blowing element 5 has the opening 6
It is attached in the state of being inserted into. A heat conduction plate 7 that is in close contact with the lower surface of the mold portion 5a of the thermal fuse blowing element 5 is arranged between the printed circuit board 2 and the controller case lower portion 3b. A large current flows through the heat conducting plate 7 such as the power switch 11, the heating area changeover switch 12, the relay 34 (see FIG. 6) arranged on the printed circuit board 2,
It has an area that can cover the lower part of parts that may generate heat due to poor contact or the like.

As shown in FIG. 2, the heat-conducting plate 7 includes a heat-resistant and flame-retardant insulating layer 7a and a metal layer 7 having excellent heat conductivity.
b, the insulating layer 7a is placed on the printed circuit board 2 side to maintain insulation from the wiring, and the metal layer 7b is used for heat conduction and also for heat insulation to the lower part 3b of the controller case. There is. In addition, as shown in FIG. 3, protrusions 8 are dispersedly formed on the metal layer 7b to reduce the contact area with the lower part 3b of the controller case so that the heat of the heat conduction plate 7 is transferred to the lower part 3b of the controller case. It's hard to communicate. The temperature inside the controller 1 is detected by a thermistor 39 (see FIG. 6) provided in the controller 1 as a countermeasure when the controller 1 is covered with a seating team or the like and the internal temperature rises due to heat from the carpet body 21. Then, the temperature control circuit is operated to stop the energization to the heating wire 29 to cut off the temperature rise source. However, when the controller 1 has a heat generation source, it is useless. Controller 1
When heat is generated in the inside, for example, due to contact failure of switches through which a large current flows, failure of parts, defective soldering, etc., heat is transmitted from the heat conduction plate 7 to the thermal fuse blowing element 5. When the generated heat exceeds the fusing temperature (for example, 96 ° C.) of the thermal fuse 33, the thermal fuse is fused and the power supply circuit is cut off. Therefore, even if the heat generated in the controller 1 does not lead to ignition,
It is possible to maintain safety by cutting off the power supply circuit before the controller case is discolored or deformed by heat and affects the installation floor surface.

[0009]

As described above, according to the present invention, the thermal fuse and the thermal fuse arranged on the printed circuit board in the controller for performing temperature control, safety control, etc. of the electric carpet etc. When the abnormal heat generation on the printed circuit board occurs, the heat is conducted from the heat conduction plate to the thermal fuse, and the thermal fuse is melted by thermal connection through the thermal fuse. Therefore, the temperature fuse as a safety device against abnormal heat generation on the carpet side also operates as a safety device against abnormal heat generation on the controller side.
More complete safety devices such as electric carpets can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an electric carpet controller according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a heat conduction plate according to the example.

FIG. 3 is a partial plan view of the heat conducting plate according to the embodiment on the metal layer side.

FIG. 4 is a plan configuration diagram of an electric carpet common to the embodiment and the conventional example.

FIG. 5 is a structural diagram of a heating cord common to the embodiment and the conventional example.

FIG. 6 is an electric circuit diagram of an electric carpet common to the embodiment and the conventional example.

FIG. 7 is a plan view of a thermal fuse blowing element common to the embodiment and the conventional example.

FIG. 8 is a side view showing a mounting state of a thermal fuse blowing element in a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Controller 2 ... Printed circuit board 3 ... Controller case 5 ... Thermal fuse fusing element 7 ... Thermal conductive plate 10 ... Thermal fuse 29 ... Exothermic wire R1, R2 ... Exothermic resistance

Claims (1)

[Claims] 1. A safety device such as an electric carpet in which a heating wire controlled by a control circuit provided on a printed circuit board is connected to a power supply circuit via a thermal fuse, wherein the printed circuit board and the thermal fuse are provided. A safety device such as an electric carpet characterized in that is directly or indirectly connected via a heat conduction plate.