JPH03101026A - Thermal fuse - Google Patents

Abstract

PURPOSE:To prevent the occurrence of malfunction at the preset temperature or below and obtain the stable performance by providing the second electrode which can be elastically shrunk and is brought into contact with another conductor in the elastic shrinkage state on the opposite side to the soluble pellet of an electrode plate. CONSTITUTION:The second electrode 20 is provided in advance at the center section on the opposite side to the soluble pellet 13 of an electrode plate 16, and the second electrode 20 is constituted of a conducting small spring 20a fixed to the electrode plate 16 at one end section by spot welding and a small electrode plate 20b fixed to the other end section of the small spring 20a likewise by spot welding. When the soluble pellet 13 is melted slightly at the preset temperature or below, only the small spring 20a of the second electrode 20 is extended, the small electrode plate 20b is kept in contact with the other conductor 18, and this connection state is maintained. No malfunction occurs at the preset temperature or below, and the stable performance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a temperature fuse that breaks the connection between one conductor and the other conductor at a set temperature.

(Prior Art) Conventionally, as this type of temperature fuse, one shown in FIG. 7 has been provided. This thing consists of a cylindrical conductive case 2 connected to a negative conductor 1, a fusible pellet 3 that melts at a set temperature, a spring seat 4 and an electrode plate 5, and an electrode plate 5 placed on the opposite side of the fusible pellet 3. The first spring 6 that presses the electrode plate 5 toward the meltable pellet 3 side, and the spring 7 of the ji2 that presses the electrode plate 5 toward the fusible pellet 3 side are housed. It is attached so as to be in contact with the electrode plate 5, so that one conductor 1 and the other conductor 8 are connected and conductive through the path of one conductor 1 - case 2 - electrode plate 5 - other conductor 8. It has become.

In the above-mentioned state, when the soluble pellet 3 reaches the set temperature, it melts as shown in FIG.
The first spring 6 expands and releases the pressing force of the electrode plate 5 toward the soluble pellet 3 side, and the second spring 7 conversely presses the electrode plate 5 toward the soluble pellet 3 side. Then, the electrode plate 5 is separated from the other conductor 8, and the connection between the other conductor 8 and one conductor 1 is severed.

(Problem to be Solved by the Invention) In the above-mentioned product, the soluble pellets 3 have a property that, even if the temperature does not reach the set temperature, when the temperature rises to near it, the melt starts gradually. There is a problem in that when the temperature rises, the device operates as described above and becomes unusable. Moreover, for this reason, there is also a problem in that the temperature cannot be raised to near the set temperature even during normal use.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a temperature fuse that can prevent malfunctions below a set temperature and provide stable performance.

[Structure of the Invention] (Means for Solving the Problems) The temperature fuse of the present invention includes a case to which one conductor is connected, a fusible pellet that melts at a set temperature, an electrode plate, and a reversible electrode plate. A first spring that presses the molten pellet side and a second spring that presses the 1s electrode plate toward the soluble pellet side are housed, and further, on the opposite side of the soluble pellet side of the electrode plate, This conductor is characterized in that it is provided with a second electrode that is elastically expandable and in contact with the other conductor in its elastically contracted state.

(Function) According to the above means, when the soluble pellet melts a little, the second electrode simply stretches, and the second electrode continues to be in contact with the other conductor, thereby changing the connection state. maintain.

(Example) Hereinafter, a first example of the present invention will be described with reference to FIGS. 1 to 3.

First, in FIG. 1, a case 11 is formed of a conductive material into, for example, a cylindrical shape, and one conductor 12 is connected to one end thereof (the left end in the figure). Further, on one end side of the inside of the case 11, there is a soluble pellet 1 that melts at a set temperature.
3 is stored in the case 11, and then a spring seat 14. First spring 15. An electrode plate 16 whose outer diameter is equal to or greater than the inner diameter of the case 11. The second spring 17 is housed in order, and the insulator 19 into which the other conductor 18 is inserted is attached to the opening at the other end of the case 11 (the right end in the figure).

As a result, in the case 11, the first spring 15 presses the electrode plate 16 toward the side opposite to the soluble pellet 13, and the second spring 17 presses the electrode plate 16 toward the soluble pellet 13 side.

Therefore, the electrode plate 16 is provided with a second electrode 20 in advance at the center of its surface on the anti-fusible pellet 13 side, and in this case, this second electrode 20 has one end connected to the electrode plate. It consists of a conductive small spring 20a fixed to the small spring 20a by spot welding or the like, and a small electrode plate 20b fixed to the other end of the small spring 20a by spot welding or the like. It can be elastically expanded and contracted, and the small electrode plate 20b is in contact with the other conductor 18 in its elastically contracted state. In addition,
In this case, the small electrode plate 20b and the external conductor 18 are each plated with silver to minimize their contact resistance.

Now, in the case of the structure as described above, one conductor 12 - case 11 - electrode plate 16 - second electrode 20 (
Small spring 20a - Small electrode plate 20b) - Other conductor 1
8, one conductor 12 and the other conductor 18 are connected and conductive.

In this state, if the soluble pellet 13 melts, and if the melting is due to the temperature below the setting and is small, the first spring 15 will expand by that amount and the electrode Although the pressing force of the plate 16 toward the anti-fusible pellet 13 side is loosened and the second spring 17 continues to press the electrode plate 16 toward the soluble pellet 13 side, in this case, the second
The electrode 20 keeps the small electrode plate 20b in contact with the other conductor 18 by simply expanding the small spring 20a,
Maintain that connection.

On the other hand, if the melting of the soluble pellets 13 is large based on the set temperature, the elongation of the first spring 15 becomes large, as shown in FIG. The pressing force of the electrode plate 16 towards the side opposite to the soluble pellet 13 by the second spring 17 becomes loosened, and on the other hand, the pressing force of the electrode plate 16 towards the soluble pellet 13 side by the second spring 17 greatly advances. The second electrode 20 is also unable to keep the small electrode plate 20b in contact with the other conductor 18 and separates, thereby breaking the connection between both conductors 12.18.

In contrast to the above, FIGS. 4 to 6 show a second embodiment of the present invention, and the only difference from the first embodiment is that the small spring 20a and the small electrode plate 20b described above are different from each other. In place of the second electrode 20, a second electrode 21 made of a leaf spring bent in a square shape is used, and even with this, the melting of the soluble pellets 13 is prevented. If it is a little, the second electrode 21 made of the leaf spring will only expand, as shown in FIG.
As shown in FIG. 6, the second electrode 21 separates from the other conductor 18 only when the soluble pellet 13 melts to a large extent as the second electrode 21 continues to be in contact with the conductor 18, so that the same effect as described above can be obtained. In this case as well, the second electrode 21 is fixed to the electrode plate 16 by spot welding or the like, and its surface is plated with silver.

[Effects of the Invention] As is clear from the above description, according to the temperature fuse of the present invention, if the soluble pellet slightly melts, the second electrode will only expand, and the other supply Since the second electrode continues to be in contact with the electric wire and maintains its connection state, unlike conventional methods in which the connection state is easily broken, the second electrode does not malfunction due to temperature rise during transportation, etc. This eliminates the need for storage, and allows the temperature to be raised close to the set temperature even during normal use, which has the excellent effect of providing stable performance.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a sectional view in a normal state, FIG. 2 is a sectional view in a state where the soluble pellets are slightly melted, and FIG. Figure 3 is a cross-sectional view of the soluble pellet in a largely melted state. 4 to 6 show a second embodiment of the present invention, in which FIG. 4 is a diagram equivalent to FIG. 1, FIG. 5 is a diagram equivalent to FIG. 2, and FIG. 6 is a diagram equivalent to FIG. 3.
It is a figure equivalent figure. Furthermore, Fig. 7 and Fig. 8 show the conventional one, with Fig. 7 corresponding to Fig. 1, and Fig. 8 corresponding to Fig. 3.
It is a figure equivalent figure. In the drawing, 11 is a case, 12 is one conductor, 13 is a fusible pellet, 15 is a first spring, 16 is an electrode plate, 1
7 is the second spring, 18 is the other conductor, 20 is the second
21 indicates the electrode of m2.

Claims (1)

[Claims] 1. In a case to which one conductor is connected, a fusible pellet that melts at a set temperature, an electrode plate, a first spring that presses this electrode plate toward the side opposite to the fusible pellet, and an electrode plate facing the fusible pellet side. and a second spring that presses the electrode plate, and on the side opposite to the soluble pellet of the electrode plate,
A thermal fuse comprising a second electrode that is elastically expandable and in contact with the other conductor in its elastically contracted state.