JPS6013157Y2 - Small alarm fuse specifically for printed boards - Google Patents

Description

[Detailed description of the invention] This invention relates to a fuse enclosed in a very small sealed transparent case intended to be attached to a printed circuit board (hereinafter referred to as a printed circuit board). It is characterized by having an alarm contact that forms a closed circuit when the fuse is blown, and an alarm circuit terminal.

Although it is desired that recent electronic devices be further downsized, there is also a demand for systematization of production processes and easier maintenance.

For this reason, printed boards used in electronic devices are required to have high-density mounting of electronic components, and it is strongly desired that the fuses mounted on printed boards not only be smaller, but also have a function that indicates when the fuses are blown. There is.

Although conventional fuses for printed circuit boards are satisfactory in terms of miniaturization, none are equipped with so-called alarm contacts that form a closed circuit when the fuse blows.

The fuse of the present invention satisfies the above requirements and will be explained in detail below with reference to the drawings.

Fig. 1 is a perspective view showing an analysis of the structure of the fuse according to the present invention, and Fig. 2 is a diagram showing normal operation of the fuse shown in Fig. 1.
FIG. 3 is a front view of the structure at B after the fusible material is fused.

In the figure, 1 is a cover, 2 is a main body (base plate), and the main body and cover are adhered and sealed using strong adhesive plastic.

3 is a fusible body (fuse element), 4 is a fuse terminal A, 5 is a fuse terminal B, 6 is an alarm terminal A, 7 is an alarm terminal B, 8 is a coil spring using an elastic material, 9 is a coil spring that presses the coil spring 8. A lid-shaped insulator for lowering, 10 is a plastic material for sealing.

The fuse is assembled as follows.

Both terminals of the fusible body 3 are fixed between the fuse terminals 4 and 5.

At this point, the fusible body is connected between the fuse terminals, but in a tension-free state.

Next, the coil spring 8 is placed inside the insulator 9, and the compressed coil spring is inserted with the insulator from the lateral direction of the main body 2 as shown in FIG. 2A by applying force from above.

After the coil spring 8 held down by the insulator 9 is stored in a predetermined position, that is, in the center of the horizontal plate of the alarm terminal A6, the coil spring 8 is
Uncompress.

The coil spring tries to stretch, but the protrusion 9a in the center of the insulator contacts the middle part of the fusible body 3, suppressing the force of the coil spring's extension.

The coil spring is an elastic coil plated, and the terminals 4 to 7 are plated thin metal plates such as brass.

Next, when the fusible body 3 is melted or cut, the force that was holding down the extension of the coil spring 8 disappears, as shown in FIG. 2B.
The tip of the coil spring 8 comes into contact with the alarm terminal B7 while pushing up the insulator 9, and the coil spring short-circuits the alarm terminals A and 8.

An alarm operation is performed by an external circuit connected to B.

Furthermore, since a cover made of a transparent material is used at this time, the position of the insulator 9 can be confirmed visually and the melting can be detected.

The external shape of the fuse shown in Figure 1 according to the present invention is 8 (height) xlOx15 (cabin 3), excluding the terminal part, which is 15 x 8
Terminals are arranged at appropriate intervals on the surface of the main body 2 of (TrrA).

Since this type of fuse has a sealed structure in which the main body and cover are sealed with resin, it is possible to wash the entire body (especially printed circuit boards with the fuse attached).

FIG. 3 is a front view showing the structure of another fuse embodying the present invention.

The only difference between FIG. 3 and FIG. 2 is the structure of the insulator 9, but instead of providing a protrusion 9a at the upper center, the insulator 9 has a structure that simultaneously pushes up two points near both ends of the fusible body 3. A protrusion 9b*9c is provided.

FIG. 4 is a front view A and a side view B showing the structure of yet another fuse embodying the present invention.

This structure is such that the central portion of the fusible body 3 is pulled by the elasticity of the coil spring. Reference numeral 11 is a rising edge from the main body 2 for supporting the insulator 9, and the upper end of the coil spring 8 is attached to this rising edge.

12 is a metal contact plate attached to the spring 8.

As is clear from the figure, the insulator 9 has an inverted T-shape and has a notch in its upper part that penetrates the fusible body 3. Under normal conditions, the downward force of the coil spring 8 compressed between the riser 11 and the contact metal plate 12 When the fusible body is fused, the contact metal plate 12 at the lower end of the coil spring is operated to push the fusible body 3 downward.
Press down further to short-circuit alarm terminals 6 and 7.

As explained above, the fuse of the present invention is small and equipped with alarm and display functions to indicate melting or disconnection of the fusible material, so it cannot be installed on printed wiring boards that require these functions for maintenance and circuit configuration reasons. If used, there is no need for any space to install circuit components for issuing alarms, and the mounting density of printed circuit boards can be increased, contributing to the miniaturization of devices.

[Brief explanation of the drawing]

FIG. 1 is a structural perspective view of one example of a fuse according to the present invention, FIG. 2 is an operation explanatory view, and FIGS. 3 and 4 are structural views of other examples. 1...Cover, 2...Body (base plate),
3... Fusible body, 4... Fuse terminal A
, 5... Fuse terminal B, 6... Alarm terminal A, 7... Alarm terminal B, 8...
Coil spring, 9... Insulator, 10...
Plastic material for sealing, 11... Rising, 12
・・・・・・Contact metal plate, 9a, 9b, 9c...
...Protrusion of insulator 9.

Claims (1)

[Scope of utility model registration request] A small fuse that houses a pair of fuse terminals and a pair of alarm terminals in a sealed case and is attached to a printed board,
A conductor material coil spring that constantly contacts and applies tension to the fusible body fixed between both fuse terminals, and when the fusible body is broken, it stretches to short-circuit and conduct between the pair of alarm terminals, and this coil spring and the fusible body. and an insulator interposed between one alarm terminal.