JPH0321032Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a surface heating system in which a heating circuit pattern made of metal foil is formed on one side of a synthetic resin film layer, and a reflective electrode pattern also made of metal foil is formed on the other side. Concerning improvement of body structure.

BACKGROUND ART FIGS. 2 and 3 show the front and back sides of a conventional surface heating element used in hot carpets and the like. In the surface heating element 1, a continuous surface pattern 3 constituting a heating circuit is formed on the surface of a synthetic resin film layer 2 made of a synthetic resin exhibiting negative resistance-temperature characteristics such as nylon, and a continuous surface pattern 3 is formed to detect abnormal heating. A detection electrode pattern (not shown) is formed on the other side, and on the other side, a back surface pattern 5 is formed which functions as a reflective electrode for detecting abnormal heating in cooperation with the detection electrode pattern. The back pattern 5 is divided into a plurality of back pattern parts 5a, 5b, . . . to enable abnormal heating to be detected in a narrow range.

Problems to be solved by the invention In the part indicated by arrow A in Figure 3,
The back pattern portion 5x and the back pattern portion 5y face each other on the back surface with the cut portion 6 interposed therebetween. Here, the front pattern 3 overlaps above the back pattern portions 5x and 5y. This state can be changed to the fourth
As shown in the figure. In FIG. 4, the synthetic resin film layer 2 is omitted in order to clearly show how the front pattern 3 and the back pattern portions 5x, 5y overlap.

At the position where the back pattern portions 5x and 5y face each other through the cut portion 6 as described above, if foot pressure or heavy objects are repeatedly dropped, the back pattern 5 may be formed below the front pattern 3. Because of their absence, cracks, cracks, etc. gradually appeared in the surface pattern 3 along the cut portion 6, and wire breaks tended to occur.

In order to prevent wire breakage due to the cut portion 6 shown in FIG. They may be formed so that they overlap. However, the back pattern 5 is provided to detect abnormal heating in cooperation with the detection electrode pattern 4 on the front side described above, and when the back pattern 5 is formed continuous on the front side, local It may become impossible to detect abnormal heating, which may cause a fire.

Therefore, the purpose of this invention is to create a surface pattern based on the cut portion of the back pattern that functions as a reflective electrode.
It is an object of the present invention to provide a surface heating element having a structure that can effectively prevent disconnection of the conductor.

Means to Solve the Problems The planar heating element of this invention has a thermal circuit consisting of a synthetic resin film layer exhibiting negative resistance temperature characteristics and a metal foil layer formed on one side of the synthetic resin film layer. A surface pattern and a back surface pattern constituting a reflective electrode made of a metal foil layer formed on the other surface of the synthetic resin film layer. This is a surface heating element in which a cut portion extending in a direction intersecting the front pattern is formed on the back pattern portion, and the cut portion of the back pattern extends at least an oblique cut portion that is inclined from a direction perpendicular to the front pattern. It is characterized in that it is formed so that it has a part.

Operation and Effects of the Invention In this invention, the cut portion of the back pattern is formed so as to have at least a portion of the oblique cut portion that is inclined from the direction perpendicular to the front pattern. For this reason, compared to the conventional case where the cut portion is formed in the direction perpendicular to the surface pattern,
The load per unit area at the cutting part can be reduced. Therefore, it is possible to prevent wire breakage from occurring in the portion of the surface pattern that is likely to cause metal fatigue, and as a result, the life of products such as hot carpets using surface heating elements can be extended.

DESCRIPTION OF EMBODIMENTS FIG. 1 is an enlarged view for explaining an embodiment of this invention, and corresponds to FIG. 4 described above. A first layer is placed below the surface pattern 13 constituting the heating circuit through a synthetic resin film layer (not shown).
A back pattern portion 15x and a second back pattern portion 15y are formed to face each other on the back surface of the synthetic resin film layer with the cutting portion 16 in between. Here, unlike the cutting part 6 shown in FIG. 4, the cutting part 16 is located substantially along the longitudinal direction of the surface pattern 13, that is, below the surface pattern 13. It is formed to be long. Therefore, the first back pattern portion 1
5x and the second back pattern portion 15y face each other over a wider range, and as a result, even if tread pressure is repeatedly applied to the portion shown in FIG. It can be seen that the distance is much smaller than that of the cut portion 6 shown in FIG. Therefore, the surface pattern 13 located above the cut portion 16 is less prone to cracks and cracks, and is less likely to be disconnected.

It should be noted that the overall shape of the front surface pattern 13 and the back surface pattern can be designed in various shapes as required, for example, they can be constructed as shown in FIGS. 2 and 3. The synthetic resin film layer can also be made of a synthetic resin such as nylon that exhibits negative resistance-temperature characteristics, and is usually about several tens of micrometers thick. Similarly, the front surface pattern 13 and the back surface pattern can also be constructed of, for example, aluminum foil or other metal foil.

In the embodiment shown in FIG. 1, the cut portion 16 was formed to diagonally cross the surface pattern 13, but as shown in FIG.
26a may be connected to the surface pattern 23 by a parallel cut portion 26b extending in a closed manner to form a cut portion 26. In the cutting part 26 of FIG. 5, since a parallel cutting part 26b is formed, the first back pattern part 25x and the second back pattern part 25y are separated.
are opposed over a wider range than in the embodiment of FIG. Therefore, the surface pattern 23 above the cut portion 26 is smaller than in the embodiment of FIG.
The lifespan of can be extended.

FIG. 6 shows a further preferred embodiment. Here, as in the case of the embodiment in FIG. 1, the first back pattern portion 35x and the second back pattern portion 3
5y through a cut portion 36 formed obliquely close to the longitudinal direction of the surface pattern. In addition, above the cut portion 36, the surface pattern 33 itself has reinforcing pattern portions 33a and 33b extending in the same direction as the cut portion 33.
are formed on both sides. Therefore, it is possible to effectively prevent the occurrence of cracks or other cracks from the portions of both side edges of the surface pattern 33 located directly above the cut portion 36.

In the embodiments shown in FIGS. 1, 5 and 6, the front pattern portions 13, 23, 33 and the back pattern portions 15x, 15y, 25x, 25y, 35
x, 35y are formed to extend in the same direction, but in an actual surface heating element, the shape and extending direction of the back pattern do not necessarily match the shape and extending direction of the front surface pattern. For example, as shown in FIG.
Back pattern 45x where only the vicinity of 3a overlaps
In some cases, back patterns 45y, 45y are formed to face the back pattern 45x. Even in such a case, the back pattern portion 45x and the back pattern portion 45y
By making the cutting part 46 between the two parts obliquely along the extending direction of the surface pattern 43 as shown in FIG. 8, the surface pattern 43 is prevented from being disconnected above the cutting part 46. can do.

[Brief explanation of drawings]

FIG. 1 is an enlarged view for explaining the shape of the cut portion in one embodiment of this invention. FIG. 2 and FIG. 3 are a plan view and a rear view showing an example of a surface heating element. FIG. 4 is an enlarged view for explaining the shape of a cut portion in a conventional surface heating element. FIG. 5 is an enlarged plan view for explaining the shape of the cut portion in another embodiment of this invention.
FIG. 6 is an enlarged plan view for explaining the shape of the cut portion of still another embodiment of this invention. 7th
The figure is a plan view for explaining an example of the shape of the back pattern when the shape of the back pattern does not match the pattern, and FIG. 8 is a plan view showing an example of applying this invention to the pattern of FIG. 7. It is a diagram. In the figure, 13 is a front pattern, 15 is a back pattern, 15 is a first back pattern part, 15
y indicates the second back pattern portion, and 16 indicates the cutting portion.

Claims (1)

[Claims for Utility Model Registration] A surface pattern constituting a heat generating circuit consisting of a synthetic resin film layer exhibiting negative resistance-temperature characteristics and a metal foil layer formed on one side of the synthetic resin film layer; a back surface pattern constituting a reflective electrode made of a metal foil layer formed on the other surface of the synthetic resin film layer; In the surface heating element in which a cut portion extending in a direction is formed in the back pattern portion, the cut portion of the back pattern is
What is claimed is: 1. A planar heating element, characterized in that it is formed so that at least a portion thereof has an oblique cut portion that is inclined from a direction perpendicular to the surface of the heating element.