JP5105300B2 - Thermal pad - Google Patents

Description

  The present invention relates to an electric heating pad for warming the body.

  2. Description of the Related Art Conventionally, thermal equipment such as an electric mat that warms the body by sleeping under the body is known. Conventional mat-type heating devices generally have a heating wire meandering so as to cover almost the entire surface, and heat is generated by passing an electric current through the heating wire. However, in the method using the heating wire, a temperature difference is generated on the surface of the device between the portion where the heating wire is embedded and the other portion, and thus the entire surface cannot be heated uniformly.

Therefore, a thermal apparatus using a planar heating element instead of a heating wire has been proposed. For example, Patent Document 1 describes an electric mat using a planar heating element containing carbon. According to Patent Document 1, this electric mat is laid on the entire surface under the body at bedtime and used to heat the entire body.
Japanese Unexamined Patent Publication No. 2007-007122 ([0006], FIG. 1)

  Generally, an electric device having a heating element is provided with a current fuse, and safety measures are taken so that an overcurrent does not flow through the heating element and overheats. For thermal equipment that uses a planar heating element, it is natural to consider providing a current fuse to prevent abnormal overheating, but in the case of a thermal equipment that warms the body, the current fuse is sufficient safety. It is not a countermeasure. That is, it is temperature, not current, that is important for the safety of the body. Since the relationship between the temperature and current of the planar heating element varies greatly depending on use conditions, sufficient temperature management cannot be performed with current. If the limit value of the current fuse is reduced with emphasis on safety, sufficient heating cannot be performed. On the other hand, if the limit value of the current fuse is increased with emphasis on performance, There is a possibility of low temperature burns.

  In addition, the electric mat described in Patent Document 1 warms the whole body, and is not suitable for use in selectively warming only specific parts such as a shoulder, a waist, and a toe. Moreover, since the size is large, power consumption is large. Furthermore, there is a problem that it is heavy and difficult to handle.

  The problem to be solved by the present invention is to provide a thermal pad that is highly safe for the human body, can selectively warm only a specific part, is energy-saving, and is easy to handle.

The thermal pad according to the present invention made to solve the above problems is
A planar heating element that generates heat when energized;
Wiring for supplying current to the planar heating element;
A thermal fuse provided in the wiring and on the surface of the planar heating element, which cuts off a current flowing through the wiring when a predetermined temperature is reached;
A predetermined heat-resistant rubber sheet covering the planar heating element and the wiring;
With
The thermal fuse is provided at substantially the center on the surface of the planar heating element;
When the sheet heating element covered with the rubber sheet is overheated at any location, the heat generated at the overheat location is transmitted through the rubber sheet, and the thermal fuse is quickly blown out. ,
It is characterized by that.

  The thermal pad according to the present invention can appropriately prevent overheating of the planar heating element by using the thermal fuse, and is highly safe for the human body. In addition, by making the length and width of the planar heating element within the range of 20 cm to 60 cm, only a specific part of the body can be selectively warmed, power consumption is reduced, and handling is easy. is there.

  Hereinafter, a thermal pad as an embodiment of the present invention will be described with reference to the accompanying drawings.

  Fig.1 (a) is a top view of the thermal pad 10 which concerns on a present Example, FIG.1 (b) is the sectional view on the AA line of Fig.1 (a). As the heating element of the thermal pad 10, a planar heating element 11 impregnated into a cloth made of glass fiber and baked with a mixed solution of carbon powder and fluororesin is used, and the size and shape thereof are 45 cm long side, 25 cm short side, The rectangle is 190 μm thick. Since the fluororesin is a resin excellent in heat resistance and durability, it is suitable for the purpose of holding the carbon powder that generates heat when energized. By reducing the size in this way and adopting such a structure as the heating element, the power consumption of the planar heating element 11 (thermal pad 10) of this embodiment can be kept as low as 19W. . An example of such a planar heating element 11 is a flexel (trade name) manufactured by UK Flexel.

  In the vicinity of each long side of the planar heating element 11, copper electrodes 12 and 13 having a width of 1 cm are provided. FIG. 2 is a cross-sectional perspective view of the planar heating element 11 taken along line BB in FIG. As shown in FIG. 2, the planar heating element 11 provided with the electrodes 12 and 13 covers the surface with a laminate film 18 having a two-layer structure made of polyethylene and polyester. In order to prevent corrosion of the electrodes 12 and 13 due to intrusion of moisture or the like, the laminate film 18 is a polyester layer having an excellent moisture-proof property and gas barrier property, and an inner layer is a polyethylene layer having an excellent heat-sealing property. .

  As shown in FIG. 1A, both electrodes 12 and 13 are connected to a power cord via a power switch 14. In the wiring 24, a thermostat 16 and a thermal fuse 17 are provided in series, and they are arranged at substantially the center of the planar heating element 11. The thermostat 16 cuts off the current flowing through the wiring 24 when the temperature is equal to or higher than a predetermined steady temperature (for example, 45 ± 3 ° C.), and flows the current when the temperature is lower than the steady temperature, thereby changing the temperature of the planar heating element 11 to the steady temperature. Hold before and after. On the other hand, the thermal fuse 17 is blown when a predetermined critical temperature (for example, 62 ± 3 ° C.) is reached, and thereafter, no current flows through the wiring 24.

  The sheet heating element 11 is protected by being sandwiched between two folded PET plates 19. As shown in FIGS. 1A and 1B, the PET plate 19 is provided with a recess 20 for accommodating the thermal fuse 17, the thermostat 16 and the wiring 24. The type of PET used for the PET plate 19 is not particularly limited, but G-PET (glycol-modified polyethylene terephthalate) is preferably used in terms of ease of processing.

  The periphery of the PET plate 19 is covered with a rubber sheet 21 that is approximately the same size as the folded PET plate 19. The rubber sheet 21 is intended for insulation to prevent leakage from the sheet heating element 11, waterproof to prevent moisture from entering the sheet heating element 11, and heat retention for retaining the heat of the sheet heating element 11. It is. A rubber sheet 21 having a predetermined heat resistance (for example, having a heat resistance temperature of about 150 ° C.) is used. An example of such a rubber sheet 21 is a bando sheet (trade name) manufactured by Bando Chemical Co., Ltd., which is a vulcanized rubber sheet containing EPDM (ethylene propylene diene copolymer) as a main component.

  The periphery of the rubber sheet 21 is covered with a polyethylene cover 22. In the rubber sheet 21 itself, it is difficult to confirm the trace when a pin or the like is stuck. By covering the rubber sheet 21 with the polyethylene cover 22, such a trace can be easily confirmed visually. Can do.

  The periphery of the polyethylene cover 22 is covered with a decorative cover 23 using a cloth containing a photocatalyst such as titanium oxide. The decorative cover 23 is the outermost surface of the thermal pad 10 and is a portion that the body directly touches. Therefore, it is desirable to use for the decorative cover 23 a cloth containing a photocatalyst that produces effects such as antibacterial effects and deodorization when exposed to light, from the viewpoint of hygiene. In addition, it is desirable that the decorative cover 23 has an end portion that can be opened and closed and can be appropriately removed from the sheet heating element 11 for washing or the like.

  FIG. 3 is a diagram showing one example of use of the thermal pad 10 according to the present embodiment. FIG. 3 shows an example in which the waist of the user 33 is warmed. As shown in this figure, the thermal pad 10 of this embodiment can warm only a necessary part without warming the whole body of the user 33. it can. Of course, if a shoulder, a foot tip, etc. are warmed, the thermal pad 10 should just be placed under those parts. Further, in order to reduce the uncomfortable feeling given to the user 33, the thermal pad 10 is placed under the futon 32 in FIG. 3. However, if it is desired to warm a specific part more locally and quickly, it is under the body. The thermal pad 10 may be placed directly on the head.

  When the power switch 14 is turned on after the heating pad 10 is placed at a desired position, a current flows through the planar heating element 11 between the electrodes 12 and 13, and the carbon contained in the planar heating element 11 generates heat.

  When the thermostat 16 reaches a steady temperature for a while, the current supplied to the planar heating element 11 is cut off, and the heating of the planar heating element 11 is stopped. Thereafter, when the temperature of the thermostat 16 becomes equal to or lower than the steady temperature, a current flows again, and the heat generation of the planar heating element 11 is resumed. In a normal use situation, the current flowing through the planar heating element 11 is controlled in this way, and the temperature of the thermal pad 10 is maintained at a substantially steady temperature. Further, since the sheet heating element 11 is covered with the rubber sheet 21, the temperature change on the surface of the thermal pad 10 becomes gentle. Far-infrared rays having a wavelength of 8 to 15 μm are generated from carbon in the planar heating element 11 at a steady temperature.

  If overheating occurs in any part of the sheet heating element 11, the heat is transmitted through the sheet heating element 11 itself and reaches the temperature fuse 17. Since the planar heating element 11 is covered with the PET plate 19 and the rubber sheet 21 as described above, the heat generated at the overheated location is transmitted to the inside rather than the outside. Accordingly, by appropriately setting the critical temperature, the thermal fuse 17 can be quickly blown by any overheating of the planar heating element 11, and the subsequent power supply / heating is stopped, so that the user 33 Thus, an accident can be prevented without causing any harm to the heating pad 10 and without causing any serious damage to the heating pad 10. The reason why the thermal fuse 17 is arranged at the substantially center of the sheet heating element 11 is to transmit the overheating of any portion to the thermal fuse 17 in the shortest time.

The top view (a) and AA sectional view (b) of the thermal pad 10 which concerns on the Example of this invention. Sectional perspective view of the planar heating element 11 taken along line BB in FIG. The figure which shows one usage example of the thermal pad 10 which concerns on the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Thermal pad 11 ... Planar heating element 12, 13 ... Electrode 14 ... Power switch 15 ... Power plug 16 ... Thermostat 17 ... Thermal fuse 18 ... Laminate film 19 ... PET board 20 ... Recess 21 ... Rubber sheet 22 ... Polyethylene cover 23 ... makeup cover 24 ... wiring 31 ... bed 32 ... mattress 33 ... user

Claims (3)

A planar heating element that generates heat when energized;
Wiring for supplying current to the planar heating element;
A thermal fuse provided in the wiring and on the surface of the planar heating element, which cuts off a current flowing through the wiring when a predetermined temperature is reached;
A predetermined heat-resistant rubber sheet covering the planar heating element and the wiring;
With
The thermal fuse is provided at substantially the center on the surface of the planar heating element;
When the sheet heating element covered with the rubber sheet is overheated at any point, the heat generated at the overheated point is transferred to the inside of the rubber sheet, and the temperature fuse is quickly blown. ,
A thermal pad characterized by that. 2. The heating pad according to claim 1 , wherein the planar heating element is obtained by impregnating a cloth made of glass fiber with a mixed solution of carbon powder and a fluororesin and firing. The heating pad according to claim 2 , further comprising a reinforcing plate that covers upper and lower surfaces of the planar heating element.

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