JPS6149331A - Temperature overrise preventing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an excessive overheating prevention device which opens the electric circuit of an iron or other appliance when the temperature thereof rises to ensure safety.

2. Description of the Related Art Conventional Structures and Problems Generally, in electrical equipment, a thermostat having a bimetal as an operating element is used as a means for adjusting the temperature of the electrical equipment. By the way, since the thermostand is mechanical, malfunctions such as malfunctions or seizure of contacts may occur, and there is a risk that the equipment may burn out due to excessive temperature rise. As a means for preventing this excessive temperature rise, a temperature fuse is used, and when the temperature rises excessively, the temperature fuse blows out, for example, cutting off the heater circuit to ensure safety.

Figure 8 shows an example of an iron as an electrical device.A base 1 made of metal such as aluminum has a set of heaters 2 for heating it. A thermostat 4 operated by a bimetal 3 is provided in the energizing circuit of 2, and this thermostat 4 maintains the surface temperature of the pace 1 at a set value.Furthermore, as a means for preventing excessive temperature rise, the heater 2 A temperature fuse 5 is provided in the current supply circuit.

Note that 6 in the figure indicates a thermostat adjustment member.

Moreover, FIG. 9 shows an electric circuit.

The temperature fuse 5 has a temperature sensing element made of a crystalline organic compound or an easily fusible metal sealed inside a tube body, and when the temperature exceeds the temperature, the temperature sensing element melts and opens an energizing circuit.

By the way, the melting point of the temperature sensing element in the temperature fuse 5 is about 220° C. at most, and if the temperature sensing element is directly connected to the pace 1, there is no margin during normal use, and there is a problem that the temperature sensor may break. Therefore, in order to reduce malfunctions, it has been necessary to locate it in a position where there is a large degree of margin, that is, on the back side of the base cover 7 or in a space where it is difficult to receive the heat of the base 1 directly. This arrangement of the temperature fuse 5 has poor heat receiving sensitivity, and the maximum temperature of the base 1 when the temperature fuse 5 is activated becomes abnormally high, leading to melting of the pace 1, dielectric breakdown of the heater 2, and fire.

There was a risk of serious accidents such as electric shock. However, in the case of irons, there is a problem in that the internal temperature rises differently depending on how they are used, that is, when they are placed horizontally and when they are placed upright, making them prone to malfunctions such as premature cutting.

Purpose of the Invention The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide an over-temperature rise prevention device that promptly detects over-temperature rises in equipment and operates accurately to improve safety and reliability. be.

Structure of the Invention In order to achieve the above-mentioned object, the overtemperature rise prevention device of the present invention includes: a switch of an energizing circuit; a thermally responsive member that is pressurized by the opening/closing member of the switch and supports the cage/lI bending member; A heated member is provided which receives the thermally responsive member and has a heat conducting relationship with the thermally responsive member, and when the thermally responsive member reaches a predetermined temperature, it loses the supporting force of the opening/closing member and displaces the opening/closing member. The structure is such that the switch is opened, and it responds sensitively to excessive temperature rises of the heated member, and moreover, the switch can be opened to ensure safety without malfunction.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

In the figure, reference numeral 8 denotes the base of the iron, which is made of die-cast aluminum and has a seed-shaped heater 9 embedded therein, which is heated to a desired temperature by the heater 9. A space 1 formed between the pace 8 and the cover 10
1 is provided with a thermostat 14 having contacts 13 that are opened and closed by a bimetal 12. Specifically, it is supported by a mounting base 15 made of ceramic or the like fixed to a part of the cover 10, and the position of the bimetal 12 is adjusted by an adjustment member. can be adjusted.

One end of a first electrically conductive plate 16 for a switch, which is formed into an elongated shape, is fixed to the mounting base 15, and an insulating plate 1T is interposed on the upper surface of the first electrically conductive plate 16. Second
conductive plates 18 are stacked on top of each other.

Contact points 19 and 2Q are provided on corresponding surfaces near the tips of the first conductive plate 16 and the second conductive plate 18. The first conductive plate 16 has elasticity, and its tip is given a force toward the inside of the base 8. Still, the second conductive plate 18 is also elastic and has a force in the direction of the first conductive plate 16, ie it is forced to close the contacts 19.20.

An actuator 21 is provided inside the pace 8 and at a position corresponding to the tip of the first conductive plate 16. This actuator 21 is made of heat-resistant and insulating ceramic. Further, this actuator 21 includes a plate-like portion 21b having a recess 21a on the upper surface, a protrusion 21C protruding from the center of the lower surface of the plate-like portion 21b, and a pin protruding from the center of the upper surface of the plate-like portion 21b.
It consists of 21d. The protrusion 21C of the actuator 21 fits into the holding hole 22 formed on the inner surface of the base 8, and the protrusion 23 formed at the edge of the holding hole 220 abuts the lower surface of the plate-shaped portion 21b of the actuator 21. , there is a heat transfer relationship between the base 8 and the actuator 21. The diameter of the protruding seat 23 is smaller than the outer diameter of the plate-like portion 2Mb of the actuator 21. Further, the holding hole 22 has a slightly elongated shape in the longitudinal direction of the first conductive plate 16.

A cylindrical thermally responsive member 24 is provided on the upper surface of the plate-like portion 21b of the actuator 21 so as to surround the bottle 21d. This thermally responsive member 24 is made of a fusible alloy, and is designed to melt due to excessive temperature rise. Note that the thermally responsive member 2
4 may be a thermoplastic synthetic resin or a low melting point metal other than the fusible metal.

The pin 21d of the actuator 21 passes through a hole 16B formed at the tip of the first conductive plate 16, and its tip corresponds to the inner surface of the second conductive plate 18. and,
No. 1 conductive plate. The tip end of 6 presses the thermally responsive member 24 toward the base 8 . The first and second conductors 16
．． The switches 18 are connected in series to the thermostat 14 and these are inserted into the energizing circuit of the heater 9.

Next, the operation of the overtemperature rise prevention device having the above structure will be explained. The thermally responsive member 24 is designed not to melt or soften at normal iron operating temperatures. For example, when using eutectic solder, the melting temperature is adjusted by changing the blending ratio of the materials to increase the margin.

In normal use of the iron, the thermally responsive member 24 maintains its original shape and is therefore in the state shown in FIG. That is, 1st. The contacts 19,20 of the second conductive plate 16.20 are closed, and the current supply circuit of the heater 9 is closed. The temperature is adjusted by opening and closing the thermostat 14. In this state, the first conductive plate 16 and the edge of the plate-shaped portion 21b of the actuator 21 maintain a distance, and the tip of the pin 21d of the actuator 21 and the second conductive plate 18 still maintain a distance B. keep,
A) There is a relationship between B. Further, the heat of the base 8 is transmitted from the protrusion 23 to the thermally responsive member 24 via the plate-like portion 21b of the actuator 21.

If the thermostat 14 fails and its contacts remain closed, and the degree of resistance of the base 8 becomes abnormally high, the thermally responsive member 24 will melt. In addition, the tip of the first conductive plate 16, which presses the thermally responsive member 24, loses its support and is displaced in the direction of the base 8 by a distance A, as shown in FIG. In response to this, the second conductive plate 18 also attempts to displace, but since the tip position of the pin 2Md of the actuator 21 does not change, the second conductive plate 18 is displaced by the distance B, and further displacement is prevented. Ru. Since the interval A) is B, the first. The opposing distance between the second conductive plates 16 and 113 becomes narrower, and the contacts 19' and 20 open to cut off the current to the heater 9, thereby ensuring its safety.

In the overtemperature rise prevention device of the above embodiment, the conductive plate 16 forming the switch element pressurizes the thermally responsive member 24, and the thermally responsive member 24 melts or collapses by 8°, displacing the conductive plate 16 and opening the switch at 11G. This structure ensures reliable operation and improves safety. Further, the thermally responsive member 24 is received by the base 8 and has a good heat transfer relationship with the base 8 due to the pressurizing force, thereby ensuring a reliable response when the temperature rises. Further, the thermally responsive member 24 melts or collapses due to pressure.

The deformation occurs quickly, contributing to quick action of the switch. The thermally responsive member 24 may be made of synthetic resin instead of molten metal, which is also effective in reducing material costs.

Since the actuator 21 that directly receives the thermally responsive member 24 is removably attached to the base 8, it is convenient to assemble and replace the thermally responsive member 24 after operation. Further, since the actuator 21 provides insulation between the first conductive plate 16 and the metal base 3, and receives the melted thermally responsive member 24 in the recess 21a, there is no risk of electric shock or the like.

Heat is transferred from the base 8 to the actuator 21 through the holding hole 22.
This is done by the protruding seat 23 protruding from the hole edge of the hole, and the protruding seat 23
is smaller than the outer diameter of the plate-shaped portion 21b of the actuator 21, for example, due to distortion of the first conductive plate 16, the actuator 21 is tilted as shown by the dotted line in Figure 6, and the outer edge of the actuator 21 and When the base 8 is in contact, the heat transfer path of the thermally responsive member 24 can be made shorter than the protrusion 23 than the base 8, and a good heat transfer relationship can be achieved.

Since the holding hole 22 of the actuator 21 is elongated along the longitudinal direction of the first conductive plate 16, even if the first conductive plate 16 bends when pressurized, the actuator 21 cannot slide in conjunction with its tip. This allows for a good heat transfer relationship with the base.

In the above embodiments, an iron is used as the device, but the device may be an electric heating device other than the iron, such as an electric cooker or an electric stove.

Further, the base 9 may be an electrically insulating material such as a cover other than a metal body.

Effects of the Invention As is clear from the description of the embodiments described above, the temperature overrise prevention device of the present invention melts or collapses the heat sensitive member when a predetermined temperature is reached, thereby reducing the supporting force of the pressurized switch member. Since the switch is configured to open, it operates without malfunction as an overtemperature rise prevention device, and can provide a highly safe and reliable device. In addition, the heat-sensitive member is pressed against the heated member such as the base by the switch member, so it has a good heat receiving relationship, responds sensitively to excessive temperature rises in the heated member, and can be adjusted depending on the operating condition of the equipment, such as horizontal or vertical position. There is no fluctuation in heat reception even in a low temperature state, and there is no malfunction.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the main parts of an iron equipped with an overtemperature rise prevention device according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of the main parts of the same pace, Fig. 3 is a top view of the same, and Fig. 4 is A plan view of the thermostat and the temperature overheat prevention device, Fig. 5 is a plan view of the overtemperature rise prevention device, Fig. 6 is a sectional view of the same, Fig. 7 is a sectional view of the same operating state, and Fig. 8 is a conventional temperature rise prevention device. FIG. 9 is a cross-sectional view of the iron with an overheat prevention device, and its electric circuit diagram is shown. 8... Iron base (heated member), 9.
... Heater, 14 ... Thermostat, 16
...First conductive plate of the switch, 18... Second conductive plate of the switch, 19.20... Contact, 2
1... Actuator, 22... Holding hole, 23
...Protrusion seat, 24...Heat-responsive member. Name of agent: Patent attorney Toshio Nakao and 1 other person Isamu 2
Figure 3 Figure 4 Figure 5 @ Figure 6

Claims (6)

[Claims] (1) A switch of an energizing circuit, a thermally responsive member that is pressurized by the switching member of the switch and supports the switching member, and a heated member that receives the thermally responsive member and has a heat conducting relationship with the thermally responsive member. An overtemperature rise prevention device comprising a member, wherein when the thermally responsive member reaches a predetermined temperature, it loses the supporting force of the opening/closing member, displacing the opening/closing member, and opening the switch. (2) The excessive temperature rise prevention device according to claim 1, wherein the thermally responsive member is made of a fusible metal or a fusible alloy. (3) The excessive temperature rise prevention device according to claim 1, wherein the thermally responsive member is made of thermoplastic synthetic resin. (4) The overtemperature rise prevention device according to claim 1, wherein the member to be heated is made of an electrical insulator. (5) The overtemperature rise prevention device according to claim 1, wherein the switch is inserted into the heater circuit. (6) The overtemperature rise prevention device according to claim 1, wherein the opening/closing member is a contact piece of a switch.