JPH0353437Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a safety device used to protect electrical equipment etc. from high voltage surges caused by lightning, etc. Even if the protection element housed inside generates heat in the event of a failure, the so-called fail-safe mechanism is activated, which disconnects the protection element from the circuit and prevents a fire from occurring. The present invention relates to a security device equipped with a mechanism.

(b) Prior art In a safety device, when high voltage surges such as those caused by lightning are applied for a relatively short period of time, protective elements such as varistors and gas-filled discharge tubes operate safely and prevent power lines from being damaged. Protect connected electrical equipment. but,
In such a short period of time, the protection element will not overheat and can safely handle the high voltage surge, but if the high voltage surge continues to flow for a relatively long time, the protection element will overcurrent in terms of current capacity, and the varistor will etc. may overheat and damage the elements, and in that case, not only the safety function of the safety device will be lost, but also a fire accident may occur due to overheating of the varistor etc.

If the safety function is left unattended, the next time another high-voltage surge invades, the safety device will not be able to protect the connected equipment, and the connected equipment will be destroyed.

For this reason, in conventional safety devices, when a high voltage surge is applied for a relatively long period of time and the varistor overheats, the heat is used to operate a switch made of a low-melting point metal, thereby protecting the protection element. In addition to disconnecting it from the circuit, a sign to that effect is displayed outside to encourage replacement of the safety device that has lost its safety function.

As an example of such a conventional safety device, there is Japanese Utility Model Application No. 56-35390. In other words, in this safety device, one electrode of the three-electrode gas-filled discharge tube is grounded, and each of the two other electrodes is connected to the varistor via a temperature switch that is activated by the heat generated by the varistor. It consists of a switch consisting of a reed switch that operates in response to the operation of the device. In this safety device, the varistor generates heat due to high-pressure surge, and the temperature switch operates in response to the overheating of the varistor, disconnecting the protective element from the circuit, and turning on the reed switch to issue an alarm. It is something that emits.

(c) Problems that the invention aims to solve However, conventional safety devices use reed switches and magnets, which are expensive, and the positional relationship between the magnet and reed switch is important for assembly, making it difficult to assemble parts. It had the disadvantage that assembly work was time-consuming, such as requiring sufficient attention to dimensions and assembly.

The purpose of this invention is to solve the above-mentioned conventional problems, and to provide a safety device with a simple structure that is equipped with a fail-safe function, a visual display function that conveys switch operation information, and an electrical alarm function. do.

(d) Means for Solving the Problems The structure for achieving the above object will be explained using FIGS. 1 to 6 corresponding to the embodiment. A low melting point alloy is applied to each of the pair of electrode parts 16 and 17 of the protective element 11 disposed therein, with the free ends 31 and 32 of the actuating spring pieces 25 and 26 communicating with the line terminals 23 and 24 being elastically deformed. 33, 34, and facing the free ends 31, 32 of the operating spring pieces 25, 26, the fixed contacts have insertion holes 41, 42 for the following display protrusions 55, 56, which are connected to one alarm terminal 38. portions 36 and 37 are arranged, and these fixed contact portions 3
6, 37 and the free ends 31, 32 of the actuating spring pieces 25, 26, there are insertion holes 49, 5 for the display protrusions 55, 56, which are connected to the other alarm terminal 46.
0, and movable contact portions 44, 45 having spring properties that do not normally contact the fixed contact portions 36, 37 but come into contact when the operating spring pieces 25, 26 return to their original positions are disposed. , these movable contact portions 44,
Display pieces 51 and 52 made of an insulating material are disposed between the display pieces 45 and the actuation spring pieces 25 and 26, and display protrusions 5 provided on the display pieces 51 and 52.
5, 56 are the insertion holes 49, 50, 41, 42 of the movable contact parts 44, 45 and the fixed contact parts 36, 37.
, and when the operating spring pieces 25, 26 return to their original positions, the display protrusions 55, 56 protrude into the display parts 7, 8 of the insulating case 1 so as to be visible from the outside. It is something to do.

(E) Effect In the safety device of the present invention configured as above,
Normally, the actuating spring pieces 25 and 26 connected to the line terminals 23 and 24 are connected to the electrode parts 16 and 17 of the protection element 11.
Therefore, when a high voltage surge is applied to the electric line connected to the line terminals 23 and 24, the resistance value of the protective element 11, which is composed of a varistor, a gas-filled discharge tube, etc., decreases, or a short circuit occurs. The excess current is discharged to the ground through the earth terminal 18 of the protective element 11 shown in the embodiment.

In addition, when a high voltage surge lasts for a relatively long time, the protection element 11 is heated by the passing overcurrent, and the low melting point alloys 33 and 34 having a predetermined melting point are melted, and the operating spring piece is in an elastically deformed state. 25,2
The free end portions 31 and 32 of 6 are separated from the electrode portions 16 and 17 of the protection element 11 and returned to the original position.

Therefore, the free ends 3 of the actuating spring pieces 25, 26
1 and 32 are separated from the electrode parts 16 and 17 of the protection element 11, the protection element 11 inserted into the electric line as a part of a safety circuit is separated from the electric line, and further overheating is prevented. Ru. Furthermore, when the operating spring pieces 25 and 26 return to their original positions, the movable contact portions 44 and 45 having spring properties
are pressed by the display pieces 51 and 52 made of an insulating material and come into contact with the fixed contact portions 36 and 37. These movable contact parts 44, 45 and fixed contact part 3
6 and 37 are paired with alarm terminals 38 and 46.
The switch is located in the alarm circuit connected to the alarm, etc., and as mentioned above, it is normally open and the low melting point alloys 33 and 34 melt when a high voltage surge is applied for a long time. It closes only when When this switch is activated, the display protrusions 55, 56 of the display pieces 51, 52 protrude into the display parts 51, 52 of the insulating case 1, and the loss of the protective function of the safety device is visually confirmed to the outside. It is possible to display it.

(F) Embodiments Examples of the present invention will be described below with reference to the drawings.

Fig. 1 is a plan view of a security device according to an embodiment of the present invention, Fig. 2 is a longitudinal front view, Fig. 3 is a plan view of the security device with the cover removed, and Fig. 4 is a plan view of the security device with the cover removed. Front view of the safety device in the closed state, No. 5
The figure is a partial sectional view of the main part, FIG. 6 is an exploded perspective view of the main part, and FIG. 7 is a circuit diagram of the safety device.

As shown in the figure, the safety device of the present invention includes an insulating case 1, a protection element 11 disposed in the insulating case 1, and a pair of first and second elements including actuating spring pieces 25, 26 and line terminals 23, 24. a second conductive metal piece 35 comprising one conductive metal piece 21, 22, a pair of fixed contact parts 36, 37 and an alarm terminal 38;
, a third conductive metal piece 43 having a pair of movable contact portions 44 and 45 and an alarm terminal 46, a pair of display pieces 51 and 52, and the like.

Each part will be explained in detail below.

First, the insulating case 1 is formed by combining an insulating base 2 and an insulating cover 3. On the insulating base 2, for example, there is a recess 4 for accommodating the protective element 11, and each of the conductive metal fittings. recess for placing the
Insulating partition walls, screw mounting parts, etc. are formed. Further, the insulating cover 3 has holes 9 and 10 that serve as display sections 7 and 8.

Elements and metal fittings will be attached to this insulating case 1, and a protective element as shown in FIG. 3 or FIG. 11 are arranged. This protection element 11 is, for example, as shown in FIG.
Varistors 13 and 14 are connected in series on both sides with the three-electrode gas-filled discharge tube 12 in the center, and an insulating coating 15 is applied to all of them to form a single unit, and round rod-shaped electrode portions 16, 17
, and a width plate-shaped ground terminal 18 is pulled out from the central gas-filled discharge tube 12. This protection element 11 has its earth terminal 18 fixed to the line terminal arrangement portion 5 formed on one side of the insulating base 2 by screws 19, and further screwed with a screw 20 for forming a screw terminal.

In addition, the first conductive metal pieces 21 and 22 are integrated with line terminals 23 and 24 and operating spring pieces 25 and 26, and the line terminals 23 and 24 are connected to screws 27 and 2.
8 on both sides of the ground terminal 18 of the line terminal placement portion 5 on the insulating base 2, and screws 29 and 30 are screwed in to form a screw terminal. Tips (free ends) 31 and 32 of the actuation spring pieces 25 and 26 are formed into arc shapes to improve contact with the electrode parts 16 and 17 of the protection element 11, and the first conductive metal pieces 21, 22
is fixed to the insulating base 2, the free ends 31, 32 of the actuating spring pieces 25, 26 are attached to the protective element 11.
The electrode portions 16 and 17 are disposed so as to cover the electrode portions 16 and 17. Then, the actuating spring pieces 25, 26 bring the free ends 31, 32 closer to the electrode parts 16, 17 of the protective element 11 from this original position against the spring pressure, and bring them into contact with the electrode parts 16, 17, and apply solder having a predetermined melting point to the electrode parts 16, 17. The switch 5 is fixed using low melting point alloys 33 and 34 such as
8,59 are formed.

The second conductive metal piece 35 is provided with a pair of fixed contact parts 36 and 37 and one alarm terminal 38, and is fixed to the insulating base 2 with screws 39 to connect the fixed contact parts 36 and 37. are disposed opposite the free ends 31 and 32 of the actuating spring pieces 25 and 26, and an alarm terminal 38 is disposed in an alarm terminal arrangement portion 6 formed on the other side of the insulating base 2.
A screw 40 for forming a screw terminal is screwed into this alarm terminal 38.

Note that the fixed contact portions 36 and 37 have display protrusions 5.
5 and 56 insertion holes 41 and 42 are made.

Further, the third conductive metal piece 43 has a spring property and includes a pair of movable contact portions 44 and 45 and the other alarm terminal 46, and is fixed on the insulating base 2 with screws 47. Movable contact part 44,
45 at the free ends 3 of the actuating spring pieces 25, 26
1 and 32 and the fixed contact portions 36 and 37 of the second conductive metal piece 35, and the alarm terminal 46
is arranged in the alarm terminal arrangement section 6 of the insulating base 2. A screw 48 for forming a screw terminal is screwed into the alarm terminal 6.

Note that the movable contact portions 44, 45 are also provided with insertion holes 49, 50 for elongated display projections 55, 56.

Further, the display pieces 51 and 52 are made of an insulating material, and have leg portions 53 and 54 formed at the lower part, and display projections 55 and 56 projecting from the upper part. This display piece 51,5
2 has operating spring pieces 25, 2 at its legs 53, 54.
In other words, the free ends 31, 32 of the actuating spring pieces 25, 26 and the movable contact portion 4 are arranged so as to straddle the operating spring pieces 25, 26.
Placed between 4 and 45. Then, the display projections 55, 56 are inserted into the insertion holes 41, 42, 49, 50 of the fixed contact parts 36, 37 and the movable contact parts 44, 45, and the tips thereof are inserted into the display parts 7, 8 of the insulating cover 3.
It is placed in the holes 9 and 10.

Note that it is preferable that the display protrusions 55 and 56 be colored in a conspicuous color such as red, and that the display parts 7 and 8 near the holes 9 and 10 of the insulating cover 3 be colored in a color scheme that complements the display protrusions 55 and 56, such as white. .

By the way, the first conductive metal pieces 21, 22, the second
The relationship between the conductive metal piece 35 and the third conductive metal piece 43 is that the free ends 31, 3 of the actuation spring pieces 25, 26
2 is fixed to the electrode parts 16, 17 of the protection element 11, the movable contact parts 44, 45 are separated from the fixed contact parts 36, 37, as shown in FIG. Switches 60 and 61 of the alarm circuit constituted by the section are turned off. Also,
The display pieces 51 and 52 are also located at the lower part of the side far from the insulating cover 3, and the display protrusions 55 and 56 are also located at the lower part of the holes 9 and 10 of the insulating cover 3, and from the outside, the display parts 7 and 8 of the insulating cover 3 It can be seen that this is not displayed.

For example, when an overcurrent flows through the protective element 11 due to a high voltage surge being applied to the electric wires connected to the line terminals 23, 24, the electrode parts 6, 17 are heated, and the low melting point alloys 33, 34 are melted. The free ends 31, 32 of the operating spring pieces 25, 26 spring upward. This state is shown in FIG. 5, and as the actuating spring pieces 25 and 26 return to their original positions, the display pieces 51 and 52 are pushed up, which presses the movable contact parts 44 and 45, and the fixed contact parts 36 and 3
7. In this way, the movable contact portion 4
Switches 61 and 62 of the alarm circuit consisting of 4 and 45 and fixed contact portions 36 and 37 are turned on, and an alarm disposed in the alarm circuit can be activated. At that time, the display pieces 51 and 52 are also lifted together with the free ends 31 and 32 of the operating spring pieces 25 and 26, and the display protrusions 55 and 56 are removed from the holes 9 and 10 of the display parts 7 and 8 of the insulating cover 3. It protrudes toward the direction and performs a predetermined display function.

(G) Effect of the invention As described above, the safety device of the invention is activated by temperature by fixing the free ends of the pair of operating spring pieces leading to the line terminal to the electrode part of the protection element with a low melting point alloy. A switch is formed to provide a fail-safe function, and the free end of the actuating spring piece, a fixed contact part communicating with one alarm terminal, and a movable contact part communicating with the other alarm terminal are opposed to each other, and the actuating spring piece is By disposing a display piece between the free end of the piece and the movable contact part, and inserting the display protrusion of the display piece into the insertion hole of the movable contact part and the fixed contact part, and placing it in the display part of the insulating case. , it is possible to provide a visual display function and an electrical alarm function to convey operation information of the switch.

In this way, the safety device of the present invention does not use reed switches or magnets like conventional ones, but instead requires assembly of operating spring pieces, metal fittings such as fixed and movable contacts, and display pieces in a predetermined positional relationship. This simplifies assembly work and reduces product costs.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a security device according to an embodiment of the present invention, Fig. 2 is a longitudinal front view, Fig. 3 is a plan view of the security device with the cover removed, and Fig. 4 is a plan view of the security device with the cover removed. Front view of the safety device in the closed state, No. 5
The figure is a partial sectional view of the main part, FIG. 6 is an exploded perspective view of the main part, and FIG. 7 is a circuit diagram of the safety device. 1...Insulating case, 11...Protection element, 16,
17... Electrode section, 23, 24... Line terminal, 2
5, 26... Operating spring piece, 31, 32... Free terminal, 33, 34... Low melting point alloy, 36, 37...
Fixed contact portion, 41, 42...Through hole, 44, 45
...Movable contact portion, 49, 50...Insertion hole, 51,
52...display piece, 55, 56...display protrusion.

Claims (1)

[Scope of utility model registration request] A line terminal 2 is connected to each of the pair of electrode parts 16 and 17 of the protection element 11 disposed in the insulating case 1.
With the free ends 31 and 32 of the actuating spring pieces 25 and 26 communicating with the springs 3 and 24 being elastically deformed, the low melting point alloy 3
3, 34, and facing the free ends 31, 32 of the actuating spring pieces 25, 26, a fixed contact that leads to one alarm terminal 38 and has insertion holes 41, 42 for the following display projections 55, 56. between these fixed contact portions 36, 37 and the free ends 31, 32 of the actuating spring pieces 25, 26, an indicator projection 5, which is connected to the other alarm terminal 46, is provided.
A movable contact having a spring property, which has insertion holes 49 and 50 of 5 and 56, and does not normally contact the fixed contact portions 36 and 37, but comes into contact when the operating spring pieces 25 and 26 return to their original positions. A display piece 5 made of an insulating material is provided between these movable contact parts 44, 45 and the actuation spring pieces 25, 26.
1 and 52, and the display pieces 51 and 5
2 are inserted into the insertion holes 49, 50, 41, 42 of the movable contact parts 44, 45 and the fixed contact parts 36, 37, and the origin of the operating spring pieces 25, 26 is A security device characterized in that the display protrusions 55 and 56 are made to protrude into the display parts 7 and 8 of the insulating case 1 so as to be visible from the outside when returning to the posture.