JPS603510Y2 - heat generating device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a heat generating device that uses a positive temperature coefficient thermistor as a heat source.

Positive temperature coefficient thermistors have recently come into practical use as highly safe heat sources due to their self-heating control effect, which allows a large current to pass through when the temperature is low and reduces the amount of current that passes as the temperature increases. Until now, no electrical equipment has been provided that takes safety measures to deal with abnormalities in positive temperature coefficient thermistor heaters.

Therefore, if foreign matter gets mixed into the PTC thermistor heater during manufacturing, or if the PTC thermistor heater cracks due to handling or excessive inrush current, etc.,
Since an overcurrent flows and the electric circuit becomes short-circuited, sparks are generated in the lead wires and their connections, which has the disadvantage of causing fires, electric shocks, etc.

This idea was devised based on the above-mentioned circumstances, and its purpose is to quickly interrupt the circuit in the event of an abnormality in the positive temperature coefficient thermistor heater, thereby eliminating the risk of fire or electric shock and allowing safe use. The purpose is to provide an inexpensive heat generating device.

゛Hereinafter, one embodiment of this invention will be explained with reference to an electric mosquito repellent shown in Figs. 1 to 3.

In the figure, reference numeral 1 denotes a mosquito repellent main body as an electric appliance main body molded from synthetic resin.This has leg parts 2 integrally protruding from the bottom surface at three places, for example, and an engaging stepped part 3 at the upper end of the peripheral wall 1a.
has been established.

Four heating element support legs 4 are integrally protruded from the bottom wall of the mosquito trap main body 1, and ventilation holes 5 are provided on both sides of these support legs 4.

Further, on the bottom wall of the mosquito trap main body 1, connecting protrusions 6a, 6b and lead wire holding protrusions 7a, 7b are provided near the peripheral wall 1a.
are integrally protruded.

A stopper protrusion 9 is provided on the bottom wall of the mosquito repellent main body 1 at a distance from and opposite to the power cord inlet 8 which is attached to the peripheral wall 1a.
An auxiliary stopper protrusion 10 is integrally protruded, and a plurality of locking protrusions 11 to 16 are integrally protruded between the cord introduction port 8 and the stopper protrusion 9.

The locking projections 11 and 12 are plate-shaped and arranged parallel to each other, and the locking projection 13 and the other plate-shaped locking projection 1 are arranged parallel to each other.
4 are respectively disposed on the left side of the locking protrusion 11 (in FIG. 2), and locking protrusions 15 and 16 are respectively disposed on the right side of the locking protrusion 12 (in FIG. 2).

Furthermore, a protrusion 17 is integrally provided on the bottom wall of the mosquito trap main body 1 on the opposite side to the position where the locking protrusions 11 to 16 are provided.

A partition plate 18 and a lamp holding plate 19 are integrally provided on the upper surface of this protrusion 17, and four protrusions 20 are integrally provided on the right side of the partition plate 18 (in FIG. 2). Furthermore, four protrusions 21 and one auxiliary protrusion 22 are integrally protruded from the left side of the partition plate 18 (as viewed in FIG. 2).

In addition, the reference numeral 23 in the figure is a power cord, the tip of which branches into internal lead wires 24 and 25 that are wired inside the mosquito trap body 1. The lead wires 24 and 25 are attached around the cord protector 26, and the tips of the lead wires 24 and 25 are connected to terminals 28 and 29 of the heating element 27, respectively.

The heating element 27 is a positive temperature coefficient thermistor heater 30 as a heat source.
The upper opening of the heat-insulating genital body 31 with
It is formed by interposing and closing with a heating plate 33.

In addition, 34.35 in FIG. 1 is an electrode connected to the said terminal 28.29.

The heating element 27 is mounted by engaging four mounting legs integrally formed on the heating plate 33 into recessed portions provided in the heating element support legs 4.

The cord protector 26 is attached to the locking protrusion 11.
．． The power cord 23 is loosely inserted between the locking protrusions 11 and 14, and its distal end, that is, the branch base of the power cord 23, is bent into a substantially U-shape and inserted between the locking protrusions 11 and 14 to engage with them.

In other words, the substantially U-shaped tip curved portion 26a of the cord protector 26 has its inner side engaged with the locking protrusion 11, and its outer side close to and opposed to the stopper projection 9 and engaged with the locking projection 14. It is arranged as follows.

One internal lead wire 24 is connected to the cord protector 2.
6, engages with the square locking protrusion 14, then passes between the stopper protrusion 9 and the auxiliary stopper protrusion 10, and then engages with the locking protrusion 15, 16, and then the mosquito trap main body. The wires are wired along the inner surface of the peripheral wall 1a of No. 1, and are held by the peripheral wall 1a, the connecting projections 6a, and the lead wire holding projections 7a.

The other internal lead wire 25 is led out from the cord protector 26, held along the inner surface of the peripheral wall 1a of the mosquito trap main body 1 by the connecting protrusion 6b and the lead wire holding protrusion 7b, and then held between the protrusions 21 and 22. It is wired so that it passes through and connects to the terminal 29.

Further, the tip of the one internal lead wire 24 is connected to an electrode 28 via a circuit breaking resistor 36, and this resistor 3
The internal lead wire 6 is guided by the protrusion 20.

This resistor 36 is provided in series with the positive temperature coefficient thermistor heater 35, and has low wattage (approximately II2W) and low resistance (1
A carbon resistor of about 0) is suitable, and the capacity is larger than the maximum current capacity when the PTC thermistor heater 30 is used normally, and the circuit is short-circuited due to an abnormality of the PTC thermistor heater 30. If this happens, the overcurrent will cause damage, and this will cut off the circuit in the event of an abnormality.

Further, a pilot lamp 37 and its protective resistor 38 are connected in series between the tips of each internal lead wire 24, 25, and this series circuit includes a positive temperature coefficient thermistor heater 30 and a circuit breaking resistor 36, as shown in FIG. It is connected in parallel to a heat generating device consisting of a series circuit with.

The pilot lamp 37 is fitted into and supported by a groove provided in the lamp holding plate 19, and the internal lead wire of the protective resistor 38 is guided by the protrusion 21.

Further, reference numeral 39 in FIG. 1 is a cover made of synthetic resin, which is placed over the top opening of the mosquito trap main body 1.

That is, the lower end of the cover 39 is formed with an engaging step portion 40 that engages with the retaining step portion 3.
Reference numeral 9 designates a connecting leg 41 that integrally projects from the connecting protrusion 6aw6b.

The tip of the connecting leg 41 has a claw shape, and this claw portion 4
1a passes through a locking hole 42 formed in the upper surface of the connecting projections 6a, 6b and engages with the edge of the hole.

Therefore, when this cover 39 is pressed downward while fitting the engaging step portions 3 and 40 onto the upper surface of the mosquito trap main body 1, the connecting leg 41 is elastically deformed and the claw portion 4 is pressed downward.
1a is inserted through the locking holes 42 of the connecting protrusions 6a and 6b, and is locked to the edge of the locking hole 42. As a result, the mosquito trap main body 1 can be easily attached without using screws, welding, or other means. It is now possible to close the lid.

The heating plate 33 is located approximately in the center of the cover 39.
A window 43 is formed opposite to the heating plate 33 so that the mat A impregnated with a drug can be placed on the heating plate 33 through the window 43.

However, in the electric mosquito repellent configured as described above, if the positive temperature coefficient thermistor heater 30 has been contaminated with foreign matter during its manufacture or has cracked during handling, the circuit may be damaged when the power is turned on. Since an overcurrent flows through the circuit and causes a short circuit, this overcurrent flows through the circuit breaking resistor 36.
When the current flows, this resistor 36 is instantly destroyed and the circuit is cut off.

Therefore, there is no risk of fire caused by sparks generated at the joints between the lead wires, or electric shock caused by leakage of current.

In addition, current fuses are generally used to break such circuits, but current fuses have the disadvantage of being quite expensive, so low-wattage, low-resistance circuit-breaking resistors are quite inexpensive. Because of this, its practical effects are great.

Note that this invention is not limited to being implemented only in the heat generating device of the electric mosquito repellent according to the above embodiment, but can be implemented as long as it is a heat generating device that uses a positive temperature coefficient thermistor heater as a heat source.

As explained above, this device is inexpensive because it is formed from a positive temperature coefficient thermistor heater and a circuit breaking resistor that is connected in series with the heater and is destroyed by an overcurrent flowing due to an abnormality in the positive coefficient thermistor heater. It is possible to provide a heat generating device that is both large and safe to use.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view of an electric mosquito trap equipped with a heat generating device according to an embodiment of this invention, Figure 2 is a plan view of the mosquito trap body showing its wiring structure, and Figure 3 is an electric circuit diagram. It is. 30...Positive characteristic thermistor heater, 36...
...Circuit breaking resistance.

Claims (1)

[Scope of utility model registration request] A heat generating device comprising a positive temperature coefficient thermistor heater and a circuit breaking resistor connected in series with the heater and destroyed by an overcurrent flowing due to an abnormality in the positive temperature coefficient thermistor heater.