JPH039237Y2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) This invention relates to a wire fuse that clearly indicates a small current blowout and a large current blowout indication.

(Prior Art) This type of electric wire fuse includes one with a relatively small breaking capacity, which is made by arranging a fusible body in which a small current fusing part and a large current fusing part are connected in series in a transparent container;
In addition, there is a relatively large breaking capacity type in which an arc extinguishing agent such as arc extinguishing sand is placed around the large current fusing part, and there is also a type in which an indicating resistance wire is placed in parallel with the fusible material, When a fusible material is fused, the display film changes color due to the heat generated by the display resistance wire when the fusible material is fused. Some display devices are known.

(Problem to be solved by the invention) However, in the case of a display structure that utilizes the heat generated by the display resistance wire as described above, the display resistance wire has no effect on the electrical path between the two connection terminals in normal operation. Therefore, even if the display resistance wire is disconnected or there is a problem with the connection when manufacturing the fuse, it is difficult to find such a fuse after manufacturing is completed. When placed on railroad tracks, there is a risk that no indication will be displayed even if the fusible material is fused.

In addition, the discoloration of the display film varies depending on the amount of heat generated, and in the event of a failure, it takes a long time for a worker to search for the wire fuse in the above state, which can cause a long power outage. It was also familiar.

Furthermore, since the display resistance wire forms an electrical path after the fusible body melts, the fault point recovers immediately after the fusible body melts or is cut off, and a small current flows that does not cause the display resistance wire to melt, resulting in this state. If this continued, the display resistance wire would continue to generate heat at a high temperature, and there was a risk that nearby objects, such as the insulating tube, would be scorched, causing deformation, damage, and destruction.

Structure of the invention (means for solving the problem) This invention was devised to solve the above-mentioned problem, and this invention consists of a pair of lead wire connection terminals inserted at both ends of a transparent insulating cylinder. A high current fusing part and a small current fusing part are fixed in series and arranged in an inner cylinder filled with arc-extinguishing sand between the same connection terminals,
In the electric wire fuse in which the inner cylinder and the small current fusing part are covered with the insulating cylinder, a large current fusing indicator is provided on the outer peripheral surface of the inner cylinder, and a large display identification cylinder is placed on the outer peripheral position of the inner cylinder. A display identification cylinder is fitted freely between the current fusing display position and the non-display position, and a display identification cylinder is placed between the inside of the display identification cylinder and the inner cylinder, and the small current which is the large current fusing display position is always installed. A biasing member is interposed to bias the display to move toward the fused part, and an insulating thin tube is provided in parallel with the inner cylinder between the inside of the display identification cylinder and the inner cylinder. A resistance wire for display, which is electrically connected in parallel to the large current fusion section, passes through the insulating thin tube, and one end of the resistance wire for display is applied to the display identification tube by the urging force of the biasing member. The high current fusing indicator on the outer circumferential surface of the inner cylinder is always covered by the display identification cylinder.

(Function) With the above configuration, the biasing force of the biasing member is always applied to the display identification tube, and if the display resistance wire is broken during manufacturing, the display identification tube operates to display, Not only can defective products be easily removed, but the low current fusing section can be directly seen when it has blown.

Also, when the high current fusing section operates to cut off, the voltage across the display resistance wire increases, causing a large amount of current to flow through the display resistance wire, causing it to melt, and as a result, the stored power in the biasing member is released. The display identification cylinder is reliably moved toward the small current fusing part, and the large current cutoff indicator on the inner cylinder is clearly displayed on the outside.

(Embodiment) An embodiment embodying this invention will be described below with reference to FIGS. 1 to 4. The insulating cylinder 1 is made of a heat-resistant transparent synthetic resin such as polycarbonate, and There is a locking flange 2 on the inner periphery of the part.
is formed. Support cylinders 3 and 4 made of synthetic resin are fitted and adhered to the inner periphery of both ends of the insulating cylinder 1, and base ends of lead wire connection terminals 5 and 6 are fitted into both support cylinders 3 and 4, respectively. There is. A pair of pins P are inserted through the outer periphery of both ends of the insulating cylinder 1, respectively, passing through the support cylinders 3 and 4 and the lead wire connection terminals 5 and 6 in the diametrical direction.

The outer end surface of the lead wire connection terminals 5 and 6 protruding from the insulating tube 1 has a connection hole 5 for connecting the lead wire.
a and 6a are recessed. Further, protective covers 7 and 8 are fitted onto the outer periphery of both ends of the insulating cylinder 1 and a part of the outer periphery of each of the connection terminals 5 and 6, respectively, and adhered with an adhesive, thereby sealing the insulating cylinder 1. An engagement groove 7a is formed on the outer periphery of the tip of the protective cover 7, and a terminal cover 8 made of synthetic resin and formed into a substantially cylindrical shape is attached to the engagement groove 7a to secure the connection terminals 5 and 6. Protects the outer periphery.

A circular fitting protrusion 9 is protruded from the inner surface of one of the support tubes 3, and the insulating tube 1 is attached to the fitting protrusion 9.
An inner cylinder 10 made of fiber-reinforced plastic or the like and having one end closed is fitted onto the outside so as to form a slight space with the inner peripheral surface of the cylinder. The outer peripheral surface of the inner cylinder 10 is painted with a highly bright color, for example red, as a large current fusing indicator. The inner end surface of the connecting terminal 5 is disposed correspondingly within the inner cylinder 10, and a connecting protrusion 11 is provided at the center of the inner end surface to protrude inward.

Between the connecting protrusion 11 and the inner end of the corresponding connection terminal 6, a high-temperature fusible material 12 constituting a high-current fusing section and a low-temperature fusible material 13 serving as a small-current fusing section are connected in series together with the arc-extinguishing sand S described later. has been done. That is,
One end of the high temperature fusible body 12 is caulked to the connection protrusion 11, and the other end is connected to a connection fitting 14 tightly fitted into the center of the end of the inner cylinder 10. Also, one end of the low temperature fusible body 13 is connected to the high temperature fusible body 12 via the connecting fitting 14, and the other end is inserted into the inner end of the connection terminal 6 and connected to the connection conductor 16 to be caulked. has been done.
Further, the inner cylinder 10 is filled with arc-extinguishing sand S.

A display identification cylinder 19 having an inward flange 20 at one end is fitted onto the inner cylinder 10 so as to be freely movable,
A coil spring 21 as a biasing member is interposed between the inward flange 20 and the display identification cylinder 19. Note that one end of the coil spring 21 is reduced in diameter as shown in FIG.
The other end is wrapped around the inward flange 2.
A stopper tube 21a made of copper is caulked to the protruding portion that is inserted through the tube 0 and protrudes to the outside. Further, the display identification cylinder 19 is colored in a different color from the large current fusing indicator of the inner cylinder 10, for example, white.

Further, an insulating thin tube 22 made of alumina porcelain or the like is inserted and fixed in the inner cylinder 10 along the axial direction, with one end disposed close to the end surface of the fitting protrusion 9, and the other end connected to the inner cylinder 10. It protrudes outward from the end. As shown in FIG. 3, one end of a connecting piece 23 made of a spring material is wound around the outer periphery of the connecting protrusion 11, and one end of the connecting piece 23 is wrapped inside the insulating thin tube 22. A display resistance wire 24 wrapped around the end is inserted. Furthermore, the other end of the display resistance wire 24 is connected to the protrusion of the coil spring 21 via the inward flange 20 to the stopper tube 21.
The coil spring 21 is crimped at point a.
is maintained in a compressed and stored state.

Therefore, a parallel circuit of the connecting protrusion 11 → the connecting piece 23 → the display resistance wire 24 → the coil spring 21 → the connecting fitting 14 is constructed for the high temperature fusible body 12.

The operation of the electric wire fuse configured as above will be explained.

Now, when a small current exceeding the rated current flows between the connecting terminals 5 and 6 for a predetermined period of time due to overload or the like, the low temperature fusible body 13 melts. This blown state can be visually recognized through the insulating tube 1, and it can therefore be seen that the electric wire fuse has been blown by a small current.

In addition, when a large current flows due to a short circuit, etc., the high temperature fusible material 1
2 fuses and sparks, and the metal vapor is diffused into the arc-extinguishing sand S and cooled, and a caterpillar-like high-low antibody is formed and blocked. When the high-temperature fusible body 12 interrupts the voltage, the voltage across both ends of the display resistance wire 24 increases, and a large amount of current flows through the display resistance wire 24.
is reliably fused by the stored force of the coil spring 21. Then, the stored force of the coil spring 21 is released, and as a result, the display identification cylinder 19 is moved to the right in FIG. The large current fusing display sign on the outer periphery will be visible from the outside.

Unlike conventional displays, this display state is always displayed in a constant color with high brightness without relying on discoloration of the display film, so it is not only easy to investigate the display state, but also prevent the display resistance wire from continuing to generate high temperature heat. Unlike conventional methods, there is no deformation, damage or destruction of the insulating tube, etc.

Therefore, this blown state can be visually recognized through the insulating tube 1, and it can therefore be seen that the electric wire fuse has been blown by a large current.

Note that even if a caterpillar-shaped high-resistance body formed by melting the high-temperature fusible material 12 and the arc-extinguishing sand S comes close to the display resistance wire 24, the insulating thin tube 22 does not close to the display resistance wire 24. Since the display resistance wire 24 is placed on the outer periphery and does not come into contact with a high resistance object, for example, the display resistance wire 24 on the coil spring 21 side that remains when fused is bonded to the high resistance object and the stored force of the coil spring 21 is reduced. There is no adverse effect on the fusing operation of the display resistance wire 24, which would hinder release.

In addition, during the manufacture of this fuse, if there is a problem with the connecting point of the display resistance wire 22, or if there is a disconnection, the display identification cylinder 19 will be operated by the coil spring 21, so the display will not operate after the fuse is completed. Fuses with defects can be easily identified, and good fuses can always be provided.

Note that this invention is not limited to the above-mentioned embodiments; for example, the large current fusing display sign may be changed to a different color,
Alternatively, it is also possible to make arbitrary changes, such as changing to letters, etc., without departing from the spirit of this invention.

Effects of the invention As detailed above, this invention improves the arc-extinguishing performance by filling the high-current fusing part with an arc-extinguishing agent.
When the small current fusing part is blown, the fused state of the small current fusing part can be seen from the outside, and when the large current fusing part is activated, the large current fusing display color on the inner cylinder can be seen from the outside. Therefore, it is possible to confirm which type of wire fuse is blowing, and the cause of the fault current can be analyzed at an early stage.

Furthermore, if there is a problem with the connecting point or disconnection of the display resistance wire during the manufacture of the fuse, the display identification cylinder will operate due to the biasing member, resulting in a defect in the display operation after the fuse is completed. This is an excellent invention for industrial use as it has the effect of easily identifying fuses and always providing good fuses.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of an electric wire fuse of an embodiment embodying this invention, Fig. 2 is a longitudinal cross-sectional view of the electric wire fuse also showing the operating state of the display tube, and Fig. 3 is a connecting protrusion and a connecting piece. 4th cross-sectional view showing the connection state of
The figure is a sectional view showing the connection state between the biasing member and the connecting fitting. 1... Insulating tube, 3, 4... Support tube, 5, 6...
Lead wire connection terminal, 7...Protective cover, 10...
Inner cylinder, 12...High temperature fusible material, 13...Low temperature fusible material, 19...Display identification cylinder, 21...Coil spring as biasing member, 22...Insulating thin tube, 2
3...Resistance wire for display.

Claims (1)

[Claim for Utility Model Registration] A pair of lead wire connection terminals are inserted and fixed at both ends of a transparent insulating cylinder, and a high current fusing part is arranged in an inner cylinder filled with arc-extinguishing sand between the connection terminals. In an electric wire fuse in which a small current fusing part is connected in series and the inner cylinder and the small current fusing part are covered with the insulating cylinder, a large current fusing indicator is provided on the outer peripheral surface of the inner cylinder 10, and A display identification cylinder 19 is fitted on the outer circumferential position of 10 so as to be freely movable between a large current fusing display position and a non-display position, and between the inside of the display identification cylinder 19 and the inner cylinder 10. Display identification tube 19
The large current fusing section is always displayed at the small current fusing section 1
A biasing member 21 is interposed between the inside of the display identification cylinder 19 and the inner cylinder 10, and an insulating thin tube 2 is provided between the inside of the display identification cylinder 19 and the inner cylinder 10.
2 are provided in parallel, and the display resistance wire 24, which is electrically connected in parallel to the large current fusing section 12, passes through the insulated thin tube 22, and the display resistance wire 2 is provided in parallel.
4 is attached to the display identification cylinder 19 against the urging force of the urging member 21, and the display identification cylinder 19 always covers the large current fusing indicator on the outer periphery of the inner cylinder 10. An electric wire fuse characterized by being arranged as follows.