JPH023268Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a gas-filled discharge tube type three-pole lightning arrester used to protect communication equipment from high voltage contact. This invention relates to an external short-circuit mechanism exclusively for gas-filled discharge tube type three-pole lightning arresters having lead terminals for connecting the device.

[Prior Art] At present, as external short circuit mechanisms exclusively for gas-filled discharge tube type lightning arresters, there are two types of external short circuit mechanisms: one in which the short circuit plates are always kept apart via a molten material melted by discharge heat, and the other in which the short circuit plates are kept apart at all times via a molten material that is melted by discharge heat. It is broadly divided into mechanisms composed of bimetals. The former mechanism requires melting of the molten material, so the speed of the short circuit operation is slow, and in fact, the short circuit cannot be completed before the open failure occurs.
Further, after a short circuit due to melting, it cannot recover by itself, and maintenance is troublesome.

On the other hand, the latter mechanism has the advantage that the above-mentioned drawbacks can be overcome by thermal displacement of the bimetal. Figures 5 to 8 of JP-A No. 55-128281 show a bimetal exclusively used for double-pole lightning arresters, and Figures 5 and 6 show a bimetal that is attached to a ring-shaped strap fixed to the outer periphery of an insulating tube. The bimetal is shown cantilevered in the axial direction.

[Problems to be Solved by the Invention] This mechanism cannot increase the L dimension of the bimetal due to constraints on the discharge gap dimension. In contrast, FIGS. 7 and 8 show a bimetal extending from a strap fixed to one of the end electrodes to the other end electrode. Although this mechanism allows the L dimension to be made longer than the former, it is not sufficient. In this case, if the bimetal of Utility Model Publication No. 39-426 is wrapped around the outer circumference of the insulating tube of the double-pole lightning arrester,
The above drawbacks can be overcome.

However, even if a bimetal is combined with the above-mentioned two-pole exclusive mechanism, the specific structure to be applied to a three-pole arrester is not clear at all.

In particular, in the case of a three-pole lightning arrester to be mounted on a printed wiring board, it is essential to have a structure that can accommodate this. The present applicant has developed a three-pole lightning arrester for mounting on a printed wiring board, which does not have a structure in which lead wires are soldered to electrodes as lead terminals.
A structure is devised in which lead terminals are integrally protruded from the electrodes to the same side, and wide spacers are protruded from the end bases of these lead terminals to separate them from the printed wiring board.

In addition, when winding a bimetal around the outer periphery of an insulating tube, it has not been determined at all which electrodes to connect to and how. Moreover, in order to avoid variations in short-circuit operation, a certain distance must be maintained from the electrode part to be connected.
This point was unclear.

However, in view of the above-mentioned circumstances, the present invention aims to provide a short-circuiting mechanism exclusively for three-pole lightning arresters mounted on printed wiring boards. , that is its purpose.

[Means for Solving the Problems] In the short circuit mechanism according to the present invention, a gas discharge gap is formed between an intermediate electrode and a pair of end electrodes via a plurality of insulating tubes, and each of the electrodes has a lead to the same side. It has a special structure used in three-pole lightning arresters for mounting on printed wiring boards, in which the terminal is integrally protruded, and the lead is integrally formed with a wide spacer from the terminal base and a protrusion of the intermediate electrode on the opposite side. be.

The characteristics of the shorting plate that constitutes the shorting mechanism are as follows.
a curved base formed of an outwardly displacing bimetal into an arc shape and wound around and thermally coupled to the electrode peripheral surface of the intermediate electrode of the lightning arrester and the peripheral surface of an insulating tube in the vicinity thereof;
a curved base that is wrapped around the outer periphery and thermally coupled; a small hole that penetrates the base end of the curved base and engages the protrusion; and a notch that extends in the longitudinal direction from the free end side of the curved base. The slot allows the lead terminal of the intermediate electrode and the spacer to enter, and the free end of the curved base separated by this slot is extended in a direction away from each other. and a pair of end contact pieces that contact each spacer of the lead terminal of the pair of end electrodes.

[Function] When the end contact piece of the shorting plate is positioned on the front side across the lead terminal, the lead terminal of the intermediate electrode is slightly inserted into the slot and the mounting position is determined. Then, when the curved base is pushed into the intermediate electrode of the lightning arrester through its opening, the small hole at the base end is fitted into the protrusion, and at the same time, the lead terminal and spacer are inserted into the slot at the free end. In this state, it is wound around the electrode peripheral surface of the intermediate electrode and the peripheral surface of the insulating tube in the vicinity thereof in a thermally bonded state in which almost the entire surface is in contact with the electrode peripheral surface of the intermediate electrode. The end contact piece is open because the folded surface is spaced apart from the spacer of the end electrode.

Next, when continuous discharge occurs and discharge heat is generated, the curved base absorbs heat directly and over its entire surface from the intermediate electrode where heat is generated most rapidly and its vicinity. As a result, the curved base immediately displaces outward and enlarges its radius of curvature, so that the end contact pieces of the free ends respectively contact the spacers and short-circuit. At the end of the discharge, the curved base is wound back onto the circumferential surface of the arrester.

[Embodiment of the invention] Fig. 1 is a front view showing an embodiment of a short-circuiting mechanism of a three-pole lightning arrester for mounting on a printed wiring board, and Fig. 2 is an exploded perspective view of the same.

In the figure, reference numeral 1 indicates a gas-filled discharge tube type three-electrode lightning arrester for mounting on a printed wiring board. A gas discharge gap is formed therein, and this arrangement is known.

Lead terminals 5 and 6 are integrally protruded from each of the electrodes 3 and 4 at the same axial interval to the same side, and each electrode 3 and 4 is provided at the base of each of the lead terminals 5 and 6. Wide spacers 7 and 8 that are separated from the printed wiring board are integrally projected.
A protrusion 9 is integrally provided on the intermediate electrode 3 on the opposite side of the lead terminal 5.

A shorting plate 10 is wound around the outer periphery of the lightning arrester 1 in the circumferential direction. The shorting plate 10 includes a curved base 11 formed by forming a bimetal into an arc shape that is displaced outwardly by heat, and a curved base 11 that extends away from each other at a substantially right angle from the free end of the curved base 11 and is folded outward at the same time. It consists of a pair of end contact pieces 12.

To be more specific, the curved base 11 is formed into an arc with substantially the same radius of curvature as the outer circumference of the lightning arrester and longer than half the circumference thereof, and a small hole 13 is formed through one base end thereof. At the other free end of the curved base 11,
A slot 14 for allowing the lead terminal 5 of the intermediate electrode 3 to enter is provided from the free end side to the intermediate portion. Also, the end contact piece 12 is connected to the slot 1.
A notch 14 is formed which is narrower on the folded side, and the folded angle is such that it makes surface contact with the contact point 8a of the spacer 8.

When installing the shorting plate 10, first, the end contact piece 11 is positioned in front of the lead terminal 6 in FIG. In this state, the lead terminal 5 of the intermediate electrode 3 is slightly inserted into the slot 14 to determine the mounting position. After that, the curved base 11
When inserted into the intermediate electrode 3 of the lightning arrester 1 through its opening, the small hole 13 is fitted into the protrusion 9 at the base end, and at the same time the lead terminal 5 is inserted into the slot 14 at the free end. positioning is done. The curved base portion 11 is wound around the electrode circumferential surface of the intermediate electrode 3 and the circumferential surface of the insulating tube 2 in the vicinity thereof in a thermally bonded state in which the curved base portion 11 is in substantially full contact with the circumferential surface of the electrode circumferential surface of the intermediate electrode 3 and the circumferential surface of the insulating tube 2 in the vicinity thereof. In this state, the folded surface of the end contact piece 12 is separated from the spacer contact 8a of the end electrode 4, and the notch 15 is separated from the circumferential surface of the end electrode, so that the end contact piece 12 is opened. ing. The curved base 11 has a fixed part 1 whose base end is spot welded as necessary.
6 can be provided.

Next, the operation based on the above configuration will be explained. Since the end electrodes 4, 4 of the lightning arrester 1 are connected between the communication lines, and the intermediate electrode 3 is grounded, continuous discharge occurs between the gas discharge gaps due to cross contact, etc., and discharge heat is generated. The discharge heat is generated by each electrode 3, 4.
and is conducted to the insulating tube 2. The curved base 11 can absorb heat directly and over the entire surface from the intermediate electrode 3 where heat is generated most rapidly and its vicinity. As a result, the curved base 11 immediately displaces outward and expands its radius of curvature, so that the end contact pieces 12 at the free ends come into contact with the contacts 8a of the spacer 8, respectively, resulting in a short circuit.
Upon completion of the discharge, the curved base 11 is wrapped around the circumferential surface of the lightning arrester 1.

Next, an experiment regarding the above-mentioned short circuit operation speed will be shown. Bimetal uses the product name (NIY),
t = 0.15 mm, w = 3 mm, the conventional mold holding structure has L = 3.2 mm, and the one of the above embodiment has L = 11.7.
mm. In the experiment, the operating time was measured after the current was variably set using a resistor, the switch was closed, and the bimetal was short-circuited. The operating time of the bimetal of the above embodiment was approximately seven times faster than that of the conventional bimetal.

According to the above embodiment, the length of the curved base 11 is a good arc, and the end contact piece 12 is brought into contact with the contact point 8a of the spacer 8, so that the operating speed can be greatly improved as in the above experimental example. I was able to do that.

In the above-mentioned embodiment, the length of the curved base 11 is a long arc, but the length is not limited to this.

[Effects of the invention] As explained above, the invention provides the following effects.

A shorting plate is formed by forming an outwardly displacing bimetal into an arc shape and wrapping it around the electrode circumferential surface of the intermediate electrode of the lightning arrester and the circumferential surface of the insulating tube in the vicinity thereof to thermally connect it to the curved base; A small hole is provided through the base end and engages with the protrusion, and a slot is cut in a bifurcated shape from the free end side of the curved base in the longitudinal direction to allow the lead terminal of the intermediate electrode and the spacer to enter. and extend away from each other from the free ends of the curved bases separated by the slot, and come into contact with each spacer of the lead terminals of the pair of end electrodes due to the outward displacement of the curved bases due to discharge heat. By forming a pair of end contact pieces, each of the middle and end electrodes has a lead terminal integrally protruding to the same side. We were able to put into practical use a special structure for mounting a short-circuiting mechanism on a three-pole lightning arrester for mounting on a printed wiring board, in which the protrusions of the intermediate electrodes are each integrally formed.

Just by straddling the lead wire, positioning the end contact piece towards you and pushing it in, the small hole at the proximal end of the curved base will fit into the protrusion, and at the same time the lead terminal and spacer will enter the slot at the free end. Since the short circuit plate is positioned by the short circuit board, the work of attaching the short circuit plate to the three-pole lightning arrester for attaching to the printed wiring board can be most simplified.

The short-circuit distance between the end contact piece and the spacer is kept constant by the engagement of the small hole and the projection, and in this state, the electrode circumferential surface of the intermediate electrode and the circumferential surface of the insulating tube in the vicinity are almost entirely in contact with each other. Since the curved base is wrapped in a thermally coupled state, a uniform and rapid response to the discharge heat of the three-pole arrester can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of a short-circuit mechanism of a three-pole lightning arrester for mounting on a printed wiring board, and FIG. 2 is an exploded perspective view of the same. 1... Three-pole lightning arrester for mounting on a printed wiring board, 2
... Insulating tube, 3 ... Intermediate electrode, 4 ... End electrode,
5, 6... Lead terminal, 7, 8... Spacer, 1
0...Short circuit plate, 11...Curved base, 12...End contact piece, 14...Slot.

Claims (1)

[Claims for Utility Model Registration] A three-pole lightning arrester in which a gas discharge gap is formed by an intermediate electrode and a pair of end electrodes via a plurality of insulating tubes, and each electrode has a lead terminal protruding from the same side. In the short-circuit mechanism of a three-pole surge arrester for mounting on a printed wiring board, the surge arrester is equipped with a short-circuit plate for thermally coupling discharge heat to the outside of the surge arrester, and each electrode is integrally formed in the surge arrester. The lead terminal and the terminal base are provided with a spacer integrally extended to a wide width, and a protrusion integrally projected from the intermediate electrode on the opposite side thereof, and the short circuit plate is formed by forming an outwardly displacing bimetal into an arc shape. a curved base that is wrapped around and thermally coupled to the electrode peripheral surface of the intermediate electrode of the lightning arrester and the peripheral surface of the insulating tube in the vicinity thereof;
A small hole is provided through the base end of the curved base and receives the protrusion, and a slot is cut longitudinally from the free end of the curved base to allow the lead terminal of the intermediate electrode and the spacer to enter. and a pair of spacers extending away from each other from the free ends of the curved bases separated by the slots and coming into contact with each spacer of the lead terminals of the pair of end electrodes due to outward displacement of the curved bases due to discharge heat. A short-circuiting mechanism for a three-pole lightning arrester for mounting on a printed wiring board, characterized by comprising an end contact piece and an end contact piece.