JPS6037795Y2 - Chip type fuse for protector - Google Patents

Description

[Detailed description of the invention] (a) Technical field of the invention This invention is an improvement of a chip-type fuse used in a protector to protect communication equipment connected to abnormal voltages and abnormal currents occurring in communication lines. Regarding.

(b) Technical background Figure 1 shows a circuit diagram of the above-mentioned protector which is currently widely used, where Ll and L2 are terminals on the line side, Sl and S2 are terminals on the equipment side to be connected, and E is the earth terminal. The terminals are shown, and as shown in the figure, there are four resistors R1 to R4, varistors VRI, VR2,
Fuses Fl, F2, and a gas-filled discharge tube (also called a detonator) ARR are used, and these electronic components are mounted and connected on a single ceramic substrate with a predetermined connection wiring pattern. It is equipped with several connection terminals, and is coated with an insulating coating of epoxy resin and silicone liquid for protection, except for the terminals.

Overvoltages and overcurrents that occur in communication lines due to induced lightning surges or contact with power lines, etc., are handled by the varistor VRLVR2 to a certain extent, and if it exceeds that level, the abnormal voltage is removed from the ground by the discharge of the gas-filled discharge tube ARP. However, the inflow of this abnormal current that kills insects is caused by the fuse Fl,
It is known that this can be prevented by fusing F2.

(C) Prior art and problems Figure 2 shows a conventionally used chip-type fuse, shown in a plan view a and a cross-sectional view taken along the line A-A. Fuse wire 2 is suspended connected,
It is molded with epoxy resin 3 leaving an internal space 4.

The bottom of the electrode 1.1' is fixed to a predetermined pattern wiring 6, 6' on the ceramic substrate 5 by brazing, and is coated with an insulating coating along with other mounted electronic components.

Chip type fuses Fl and F2 having such a configuration are connected and used in a safety circuit as shown in FIG. 1, and when the fuses are blown, they are recognized as an open circuit between the terminals Sl and 32 when viewed from the equipment side.

However, even if a disconnection occurs in the communication line connected to the line side terminals Ll and L2, it is recognized as an open connection between the terminals Sl and 52, so it is difficult to distinguish between the two.

A protector with a separate monitoring circuit was used to recognize this distinction, but the circuit configuration was complicated and the number of connection terminals was six, increasing production costs and reducing reliability due to the increased number of terminals. Come.

(d) Purpose of the invention An object of the present invention is to provide a new chip-type fuse for a protector that eliminates the above-mentioned drawbacks of the conventional devices.

(e) Structure of the invention The above object is to provide two elastic wires on two extended fuse wires, one end of which is fixed to one of the connection terminals of the fuse wire, and the other end of which is crimped to the image of the fuse wire. The structure according to the present invention is provided with a movable piece, and an extension of one of the connection terminals of different fuse wires is disposed below the fuse and directly below the crimp part of the elastic movable piece, and the extensions are sealed by molding. This is accomplished by a chip-shaped fuse.

In other words, the chip-type fuse according to the present invention is conventionally used separately for each line, but two fuses for both lines are expanded and assembled into one, and in this case, neither fuse is blown. An elastic movable piece is provided that constitutes a circuit that short-circuits the device side terminals even if the device side terminals are connected.

In this way, a blown fuse results in a short circuit between terminals on the equipment side, and can be clearly distinguished from an open circuit due to line breakage.

(f) Embodiments of the invention The gist of the invention will be specifically explained below with reference to embodiments shown in the drawings.

The same reference numerals indicate the same objects throughout the figures.

Fig. 3 shows a circuit diagram of a protector using a chip-type fuse according to the present invention. Fig. 4 shows a plan view a of a chip-type fuse of one embodiment, a side view b1 of a cross section taken along B-B, and a cross-sectional plane view taken along a line C-C. Illustrated in the diagram.

Fuse terminals 7, 7', 8, 8' for connecting and measuring the respective ends of the fuse wires 2', 2'' extended in the space 4' in the resin mold 3' are all formed by punching from thin metal plates. Of these, the terminals 7 and 8' on the line side are molded into a U-shape as in the past, while the terminals 7 and 8 on the equipment side are bent at right angles to the U-shaped molded parts to fill the mold space. Portions 9, 9' extended to the bottom of 4'
The tips of the extensions 9 and 9' both extend below the adjacent fuses 2' and 2'', and one end of each is connected to the terminal 7.8.
and the other end to each fuse 2'.

The tip of the elastic movable piece 10.10' which is crimped onto the terminal 2'' contacts the end of the elastic movable piece 10, 10' when the fuse is blown, thereby short-circuiting the equipment side terminals 7 and 8.

As the elastic movable piece 10, 10', a thin plate of nickel silver or phosphor bronze is used, and its tip, which constitutes the contact, together with the tip of the extension parts 9, 9', is used to maintain the reliability of the electrical contact. For example, a contact material of silver or vanadium alloy is soldered.

When a disconnection accident occurs in the communication line connected to the line side terminals Ll and L2, it is recognized as an open circuit between the terminals Sl and 32 on the equipment side, and when the fuses F1 and F2 are blown due to overcurrent, the movable piece 10 contact with the extension part 9', and the movable piece 10
' and the extension 9 is identified as a short circuit between the terminals Sl, 32.

(g) Effects of the invention As explained above, by using the chip type fuse according to the invention, a remarkable practical effect can be obtained in that it is possible to obtain a protector that eliminates the drawbacks of the conventional ones.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional protector, Fig. 2 is a plan view a and a side sectional view b of a conventional chip type fuse, and Fig. 3 is a circuit diagram of a protector using the chip type fuse of the present invention. FIG. 4 shows a plan view a, a side cross-sectional view b, and a cross-sectional plan view C of one embodiment of the chip-type fuse of the present invention. In the figure, 1.1';7,7';8,8' are terminals, 2
．． 2', 2'' are fuses, 3, 3' are resin molds, 5
is the board, 9, 9' are extensions of terminals 7, 8, 10.10'
indicates an elastic movable piece.

Claims (1)

[Scope of utility model registration request] Two elastic movable pieces are provided on two extended fuse wires, one end of which is fixed to one of the connection terminals of the fuse wire, and the other end of which is crimped onto the fuse wire. A chip-type fuse for a protector, characterized in that an extension of one of the connecting terminals of different fuse wires is disposed directly below the crimp portion of the movable piece and sealed by molding.