JPS633080Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a fuse operation display device that displays to the outside that the fuse has operated by protruding an indicator bar as the fuse operates.

As a conventional fuse operation display device of this type, there is one shown in FIGS. 1 and 2. Figure 1 is a cross-sectional view including the fuse body, in which terminal metals 1 and 2 are attached and fixed to cover both ends of an insulating outer cylinder 3 made of porcelain, etc., and 4 is a cross-sectional view of both terminal metals 1 and 2. A fuse element made of a silver wire or the like is housed in an insulating outer cylinder 3 together with an arc extinguishing agent 5 made of silica sand or the like, and 6 is an insulating element fixed to the inside of the terminal metal 1 with the opening 6a facing outside. In the display chamber made of material, a through hole 6b into which a wedge-shaped plug 7 made of an insulating material is wedged is provided at the bottom on the opposite side of the opening 6a. 8 is a spring having one end in contact with the bottom of the display chamber 6; 9 is in contact with the other end of the spring 8 at the collar 9a, and is arranged such that one end can protrude from the opening 6a when the spring 8 is released; The indicator rod has an insertion hole 9b at the other end. Reference numeral 10 denotes a locking wire made of a conductive material, which passes through the insertion hole 9b, leads out of the display chamber 6 from the through hole 6b, and has both ends electrically connected to the terminal metal 1, and wedges the plug 7 into the through hole 6b. As a result, the spring 8 is held under tension via the display rod 9 so as to store the force. Reference numeral 11 denotes a display element made of nichrome wire or the like, one end of which is electrically connected to the terminal metal 2 and the other end of which is introduced into the display chamber 6 through the center of the plug 7, and is locked with the tip of the other end. A predetermined gap 12 is formed between the wire 10 and the tensioned portion. The predetermined gap 12 is configured with a size and shape that ensures reliable separation between the locking line 10 and the display element 11 at all times, and also ensures that an arc is generated and a bridging state occurs when a circuit voltage is applied. be done. Then, the display chamber 6, the plug 7, the spring 8, the display rod 9, the locking line 10, the display element 11
This constitutes a fuse operation display device 13.
Note that the reason for providing the void 12 is as follows. That is, as shown in FIG. 2, the display element 14 connected between the terminal metals 1 and 2 causes the spring 8 to
In other conventional fuse operation display devices that store energy, a current is constantly shunted also to the display element 14, which has a negative effect on the fusing characteristics and the welding characteristics of the fuse, especially for fuses with relatively small rated currents. This is because the influence cannot be ignored, and because the display element 14 needs to be made of a relatively thin material, a sufficient stored force cannot be obtained.

Next, the operation of the conventional fuse operation display device configured as described above will be explained together with the operation of the fuse itself. First, when the fuse is normally energized,
Since the air gap 12 exists, the current flows only to the fuse element 4 and does not flow to the locking line 10 or display element 11, and the voltage applied to the air gap 12 is almost zero due to only the voltage drop of the fuse element 4. be. Here, when an accident such as a short circuit occurs in the circuit and a short circuit current flows through the fuse, the fuse element 4 first melts. As a result, a circuit voltage is applied to the gap 12 and an arc is immediately generated, resulting in a bridge state. The arc heat causes the locking wire 10 to be cut at the tensioned portion, and the spring 8 is released to cause the indicator bar 9 to protrude from the opening 6a, thereby indicating to the outside that the fuse has operated. Next, display element 1
1 is fused and the current is suddenly cut off.

However, in the conventional fuse operation display device as described above, insulation between the locking wire 10 and the display element 11 is provided by the air gap 12, so especially when the voltage is relatively rated such as 7.2KV or 3.6KV. In the case of a low fuse, a fine gap of 1 mm or less is required as the above-mentioned predetermined gap 12 in order to obtain stable operating characteristics, and this poses a drawback in that it is difficult to manufacture.

This invention was made in order to eliminate the drawbacks of such conventional fuse operation display devices.
By attaching an electrode electrically connected to the display element to the tensioned part of the locking line via a fibrous insulating member, the minute gap between the locking line and the display element can be precisely closed. It is an object of the present invention to provide a fuse operation display device that can be easily formed.

Hereinafter, a fuse operation display device according to an embodiment of this invention will be described with reference to the drawings.

FIG. 3 is a sectional view showing the fuse operation display device, and FIG. 4 is an enlarged view of the main part thereof. In the figure, the terminal metals 1 and 2, the display chamber 6, the opening 6a, the through hole 6b, the plug 7, the spring 8, the display rod 9, and the locking wire 10 are the same as those in the conventional case, so their explanation will be omitted. Reference numeral 15 indicates a thin tube made of glass cloth that is inserted through the tensioned part of the locking wire 10, and 16 is a nichrome wire or the like, one end of which is electrically connected to the terminal metal 2, and the other end of which passes through the center of the plug 7 to form a display chamber. 6 , the other end of which is connected to a conductive thin wire 17 that is wound around a thin tube 15 . The conductive thin wire 17 may be an extension of the other end of the display element 16 as it is. Then, the display chamber 6, the plug 7, the spring 8,
The display rod 9, the locking wire 10, the thin tube 15, the display element 16, and the conductive thin wire 17 constitute a fuse operation display device 18.

In the fuse operation display device according to the embodiment of the invention configured as described above, after the fuse element 4 is blown by applying a short circuit current, a circuit voltage is applied to the capillary tube 15, and an arc immediately forms the capillary tube 15. This occurs in the micro voids that exist in the glass cloth, resulting in a bridged state. Due to this arc heat, the locking wire 10 is cut at the tensioned part, and the spring 8
is released and causes the indicator bar 9 to protrude from the opening 6a, thereby indicating to the outside that the fuse has operated.
The display element 16 melts due to the current flowing during this time and the heat generated by the current flowing through the arc that continues to occur after the locking wire 10 is cut, and the surrounding arc extinguishing agent 5 is extinguished. The arc action causes the current to be cut off. in this case,
By appropriately selecting the thickness and mesh of the fibers constituting the glass cloth, extremely small and precise gaps can be easily and arbitrarily produced, and between the locking wire 10 and the conductive thin wire 17. Since a thin tube 15 made of glass cloth is interposed in the
When an arc occurs, the locking wire 10 moves smoothly without being welded to the conductive thin wire 17, releasing the spring 8, and providing a stable operation display.

In the above embodiment, the thin tube 15 made of glass cloth is used, but any fibrous insulating material having appropriate insulation and heat resistance may be used, and the shape may not be a thin tube, but may be flat, for example. It may be something like a shaped piece folded back along the locking line 10. Further, although the conductive thin wire 17 is used, for example, an electrode made of a conductive tube closely attached to the circumference of the thin tube 15 may be used, and in this case, the distance from the locking part 10 is uniform. This improves performance and provides more stable operating characteristics. Furthermore, the locking line 10
It is not necessary that both ends of the terminal metal 1 be connected to the terminal metal 1, and only one end thereof may be connected.

As explained above, this device is a lock that is electrically connected to one of the terminal metals to which both ends of the fuse element are connected, and that is latched under tension so as to store energy in a spring disposed inside the display chamber. A stop wire, an indicator rod arranged to be able to protrude from the opening of the indicator chamber when the spring is released, and one end of which is electrically connected to the other end of the indicator element that is electrically connected to the other end of the terminal metal. By providing an electrode that is connected and attached to the tensioned portion of the locking line via a fibrous insulating member, it is possible to easily form a minute gap between the locking line and the display element with precision. There is an effect.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional fuse operation display device including the fuse body, Fig. 2 is a sectional view showing another conventional fuse operation display device, and Fig. 3 is an embodiment of the present invention. FIG. 4 is a sectional view showing the fuse operation display device, and FIG. 4 is an enlarged view of the main part thereof. In the figure, 1 and 2 are terminal metals, 3 is an insulating outer cylinder,
4 is a fuse element, 6 is an indicator chamber, 6a is an opening, 8 is a spring, 9 is an indicator bar, 10 is a locking line, 1
5 is a thin tube as an insulating member, 16 is a display element, 17 is a conductive thin wire as an electrode, and 18 is a fuse operation display device. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A display chamber disposed with the opening facing outward on one side of a terminal metal fixed to both ends of an insulating outer cylinder and connected to both ends of a fuse element, and this display A spring with one end in contact with the inner wall of the chamber, a locking line made of a conductive material that is electrically connected to one of the terminal metals and locked under tension so as to store the spring, and the other springs. an indicator rod that abuts one end and is arranged to protrude from the opening when the spring is released; an indicator element having one end electrically connected to the other end of the terminal metal; What is claimed is: 1. A fuse operation display device comprising: an electrode connected to the tensioned portion of the locking wire via a fibrous insulating member; (2) The locking wire was inserted into the display chamber through a through hole provided in the wall on the side opposite to the opening of the display chamber, and was locked through the insertion hole provided in the end of the display rod on the side opposite to the protruding side. A fuse operation display device as set forth in claim 1, characterized in that the fuse operation display device is characterized in that: (3) The fuse operation display device according to claim 2 of the utility model registration, characterized in that a wedge-shaped plug is wedged in the through hole. (4) The fuse operation display device according to claim 3, wherein the display element is disposed through the plug. (5) The fuse operation display device according to any one of claims 1 to 4, wherein the insulating member is a thin tube surrounding the tensioned part. (6) The fuse operation display device according to claim 5, wherein the thin tube is a glass cloth. (7) The fuse operation display device according to claim 5 or 6, wherein the electrode is a conductive thin wire wound around a thin tube. (8) The fuse operation display device according to claim 7, wherein the conductive thin wire is formed at the end of the display element. (9) The fuse operation display device according to claim 5 or 6, wherein the electrode is a conductive tube tightly attached around the thin tube.