EP2171812B1 - Overvoltage protection device having one or more parallel-connected overvoltage-limiting elements located in one physical unit - Google Patents

Abstract

The invention relates to an overvoltage protection device having one or more parallel-connected voltage-limiting elements which are located in one physical unit, such as varistors, diodes or means of this type configured in the form of a disc, comprising a shell apparatus in order to electrically disconnect the overvoltage-limiting elements when they are thermally overloaded, and means for indication and/or signalling of the fault state which then occurs, wherein the switching apparatus is connected via a means which can be released thermally, such as adhesive or a solder, to a connecting contact of the at least one overvoltage-limiting element, and/or to an external terminal contact or plug contact. According to the invention, the switching apparatus is in the form of a solid U-shaped switching fork, the fork tines of which run essentially parallel to the side surfaces of the overvoltage-limiting element, holding the latter in the space between the tines. At least one of the fork tines rests on the at least one connecting contact and is fixed there via the means which can be released thermally wherein, when disconnection occurs, the disconnection slide is moved with the switching fork being driven and, in the process, the connection point between the fork tines and the connecting contact represents a fulcrum for the switching fork movement.

Description

The invention relates to an overvoltage protection device with one or more parallel-connected, located in a structural unit overvoltage limiting elements, such as varistors, diodes or the like disk-shaped configured means comprising a switching device to electrically isolate the thermal overload of the overvoltage limiting elements, and means for display and / or reporting the then given fault condition, wherein the switching device via a thermally releasable means, such as adhesive or solder, with a terminal contact of the at least one overvoltage limiting element and / or an external terminal or plug contact is in communication, and the at least one terminal contact itself is located on one of the side surfaces of the disk-shaped over-voltage limiting element, according to the preamble of patent claim 1.

From the EP 0 867 896 A1 An arrangement of a plurality of disc-shaped varistors as overvoltage limiting elements for a surge protective device is previously known. In the local solution, it is possible to separate each of the varistors connected in parallel separately and to trigger a corresponding error indication. Electrical connections there consist of a stranded conductor, which, however, is only limited shock current.

From the EP 0 716 493 B1 is a further device for protection against the occurrence of transient electrical overvoltages with at least two varistors and separating means previously known, where also each of the varistors is individually separable. Also, a display is provided for reporting the error state then present for each separation device. The separation takes place via prestressed, located on the narrow longitudinal edges of the disc-shaped varistors ironing, with a low-melting Lot associated with a corresponding mating contact point.

From the DE 10 2006 036 598 A1 a method for dimensioning a separation device for a surge arrester is already known, wherein the local separation movement is performed via a switching tongue, which is aligned via a permanently acting spring force in the opposite direction to the holding force produced via a protective solder. It is on the switching tongue, which must be bendable, the entire power out, with the result that only small surge currents due to the small cross-sections and the bending ability of the connection plates can be performed.

From the German utility model 90 17 577 U1 is an overvoltage protection device with parallel varistors of the same size and the same surge current capability previously known. The local varistors are arranged electrically parallel to each other. The necessary electrical connections between the varistors are realized via a bridge in the form of a copper strand and by means of a contact rail. It has been found, however, that splicing of such copper strands during surge current loads, which represents a considerable disadvantage.

In the arrangement for deriving overvoltages with one or more parallel-connected, located in a structural unit overvoltage limiting elements, such as varistors, diodes or the like DE 10 2004 024 657 A1 there is also a switching device there to electrically isolate this thermal overload of the or overvoltage limiting elements. For this purpose, the switching device between the varistor disks is arranged on a partition wall within the structural unit of two varistor disks, which are parallel and spaced apart, and there are Kontaktierungsscheiben or Kontaktierungsbleche for connecting the varistors in thermal contact with the respective switching device. The Kontaktierungsscheiben or Kontaktierungsbleche are laid so that cancel electromagnetic forces at surge load. With such a solution is indeed the However, the surge current carrying capacity improves, but the thermal coupling of the parallel-connected voltage-limiting elements to the thermally-responsive switching device is insufficient.

For the pluggable surge arrester after EP 0 905 839 A1 According to the preamble of claim 1, at least one varistor in disc form is also used, wherein a soldering point is arranged in the supply line to the overvoltage diverting element which melts under thermal load. Furthermore, a spring-biased supply line is provided in the form of a bridge, whose two ends are connected via a solder connection with other supply line parts. If the temperature at the respective solder joints is so high that the melting point of the solder is reached, the bridge is pulled out and thus an electrical disconnection of the varistor. However, in this embodiment, there is a very insufficient thermal coupling between the aforesaid bridge and the varistor. Furthermore, the surge current through the bridge soldered on both sides and the positioning of the actual separation device is insufficient.

From the foregoing, it is therefore an object of the invention to provide a further developed surge protection device with one or more parallel connected, located in a structural unit overvoltage limiting elements, such as varistors, diodes or the like disk-shaped configured means, which is overall capable of higher surge currents up into a range of 100 kA, which is not possible with the solutions of the prior art. Furthermore, the proposed embodiment of an overvoltage protection device with separating device should consist of as few parts as possible, so that an automated and therefore more cost-effective production is given. It must also be ensured that there is a secure synchronous separation in the case of two or more surge-limiting elements connected in parallel, for which it is also necessary to find a construction which ensures sufficient thermal coupling between the surge-limiting elements and the disconnecting device.

The object of the invention is achieved according to the combination of features according to claim 1, wherein the dependent claims comprise at least expedient refinements and developments.

It is therefore assumed that an overvoltage protection device with one or more parallel-connected, located in a structural unit overvoltage limiting elements, such as varistors, diodes or the like disk-shaped configured means. The overvoltage protection device comprises a switching device, in order to electrically isolate the thermal overload of the overvoltage limiting elements, in particular varistors. Furthermore, there are means for displaying and / or reporting the fault condition given in the event of disconnection. The switching device is accessible via a thermally-releasable means, such as e.g. an adhesive, a wax or a solder, with one of the terminal contacts of the at least one overvoltage limiting element and / or also with such a thermally releasable means with an external clamping or plug contact related. The at least one connection contact is in this case on one of the side surfaces of the disk-shaped, overvoltage limiting element.

According to the switching device is designed as a U-shaped, consisting of a solid material shift fork, the fork tines substantially parallel to the side surfaces of the overvoltage limiting element, this in the tine gap receiving.

The section connecting the forks is in electrical connection with one of the outer clamping or plug contacts and rests on a separating slide, which comprises at least one claw-like section which engages around the end of the shift fork located there.

The separation carriage is under bias, in particular under spring force bias, wherein the relevant force vector of the connection point between the shift fork and outer terminal or plug contact is groundbreaking oriented.

At least one of the forks is applied to the at least one terminal contact of the particular varistor and is there fixed on the aforementioned thermally releasable means, wherein in Abtrennfall the separating slide moves along with the shift fork and in this case the junction between the forks and terminal contact a pivot point with respect to the shift fork movement represents.

Since, in contrast to various solutions of the prior art, a bending movement of the switching device is not required, it can be made of a particularly massive material, so that a high surge current carrying capacity can be achieved. Also, the massive design of the shift fork results in excellent thermal conductivity so that very good thermal contact from the heat source, i. the surge limiting element towards the heat sink, i. gives the corresponding joints, which are provided with the thermally releasable means.

In a preferred embodiment, the overvoltage limiting elements consist of at least two varistor disks arranged in parallel, each of which has a first connection contact on one of its side surfaces, the further second connection contacts being electrically connected to the further one of the outer clamping or plug contacts. The respective forks of the shift fork are fixed in this embodiment, each with one of the first connection contacts on the thermally releasable means, wherein occurring currents can now flow in a parallel direction through the forks.

The separation slide is mounted in a guide, which is part of the bottom of a protective device housing receiving.

In this case, the separation slide moves parallel to the housing bottom between there openings for receiving the clamping or plug contacts.

The claw-like portions of the severance slide extend upwardly from the housing bottom, preferably having two claw-like portions at the respective outer end portions of the severance carriage to securely grasp the shift fork without causing tilting in the severing operation. The disk-shaped overvoltage limiting elements extend substantially perpendicularly from the housing bottom upwards, wherein an insulating support member is provided between the separating slide and the disk-shaped overvoltage limiting elements.

About the longitudinal outer edge of the disc-shaped overvoltage limiting means, this partially encompassing, a mounting leg for receiving a movable optical display plate is present.
The movable display plate comprises at least one, preferably two lateral projections with groove, wherein one end or both ends of the fork tine of the shift fork engage in the respective groove in order to change the position of the display plate during the separation process.

In the housing base is ausgestaltend an opening for receiving a pin, in particular pressure pin, which actuates or triggers a remote fault remotely depending on the position of the separation slide.

The terminal contacts on the side surfaces of the overvoltage limiting element, in particular of the varistor, are formed as strip-shaped, projecting from the side surface plane stop edges.

The thermally releasable means can connect both the forks with the terminals on the overvoltage limiting elements as well as the connecting the forks section with the outer clamping or plug contact.

The housing bottom of the arrangement facing ends of the stop edges then form the fulcrum for the movement of the shift fork during the separation process.

The shift fork can be manufactured as a stamped part in solid design, resulting in the already mentioned large contact surfaces and the desired high mechanical strength in terms of maximum surge current capability.

The force effect of the parallel current-carrying forks supports the strength of the intended solder joints, which in turn is for the surge current strength of advantage. In addition, the size of the soldering surface can be minimized by this entering effect.

By the execution of the U-shaped shift fork of a solid material, which does not bend as intended, and the movement of the separating device on the separating sled a secure synchronous separation of several varistors connected in parallel can be realized. It is also an excellent thermal coupling of the varistors by the common direct soldering as well as the external connection through the common solid separating bracket, i. given the shift fork.

The width of the overvoltage protection device is only slightly increased by the shift fork, so that can be found by the dimensions standard housing for the complete overvoltage protection device application.

The invention will be explained below with reference to an embodiment and with the aid of figures.

Fig. 1

eine Seitenansicht des Überspannungsschutzgeräts (ohne Gehäuse- kappe);

Fig. 2

eine Vorderansicht des Überspannungsschutzgeräts wie in Fig. 1 ge- zeigt, ebenfalls ohne Gehäusekappe;

Fig. 3

eine perspektivische Darstellung des Überspannungsschutzgeräts mit angedeutetem Drehpunkt der Abtrennvorrichtung, die eine mas- sive Schaltgabel umfasst, sowie

Fig. 4

eine Explosivdarstellung wesentlicher Elemente des Überspannungs- schutzgeräts (wiederum ohne Gehäusekappe oder Außengehäuse).

Hereby show:

Fig. 1

a side view of the overvoltage protection device (without housing cap);

Fig. 2

a front view of the surge protective device as in Fig. 1 shown, also without housing cap;

Fig. 3

a perspective view of the overvoltage protection device with indicated pivot point of the separating device, which comprises a massive shift fork, and

Fig. 4

an exploded view of essential elements of the overvoltage protection device (again without housing cap or outer housing).

The overvoltage protection device according to the embodiment is based on two varistors connected in parallel to a varistor unit 1.

On each of the side surfaces of the varistor unit 1 strip-shaped, protruding from the side surface plane stop edges 2 are present as a connection contact.

In a housing bottom 3 there are inserted external terminal or plug contacts 4, from which it follows that the surge protection device shown is designed as a plug-in part that can be used in a base part not shown.

The Indian Fig. 1 Plug contact 4 shown on the right is contacted with a common connection terminal 5 of the varistor unit 1, in particular soldered.

The actual switching device is designed as a U-shaped, massive shift fork 6, which has two spaced forks 7.

The forks 7 are connected via a section 8. This section 8 also provides the contact surface to the clamping or plug contact 4 (in Fig. 1 on the left side).

From the Fig. 2 and 3 it can be seen that the forks 7 extend substantially parallel to the side surfaces of the varistor unit 1 and the varistor unit is received in its tine gap.

The fork connecting portion 8 is encompassed by two claw-like portions 9 at its lateral ends, wherein the claw-like portions are part of a separating slide 10.

The separation slide 10 is displaceably mounted on the housing bottom 3 and consists for example of a plastic injection-molded part.

Furthermore, the separating slide 10 is under bias, which is generated by a compression spring 11. The relevant force vector shows from the junction between the shift fork 6 and in the Fig. 1 recognizable on the left side clamping or plug contact 4 in a pioneering direction.

The forks 7 abut against the stop edges 2 and are fixed there by means of a solder.

In the separation case, the separating slide 10 moves with the driving fork 6. The connection point between the forks 7 and stop edge 2 in this case represents a pivot point 12 with respect to the shift fork movement.

From the graphic representation, which is not to scale, it is clear that the shift fork 6 consists of a solid, metallic component and thus has a sufficient surge current carrying capacity.

Fig. 4 allows the guide 13 to recognize the separation slide 10, which has a matched to the dimensions of the guide 13 groove-shaped recess.

The guide 13 is part of the housing bottom 3. Between the separating slide 10 and the varistor unit 1 is still an insulating cover 14 is present.

The claw-like portions 9 of the separating slide 10 extend as shown from the housing bottom 3 upwards.

The varistor unit 1, in turn, extends perpendicularly to the bottom 3, the varistor unit 1 being partially encompassed by a fastening leg 15 via a longitudinal outer edge.

The fastening leg 15 serves to receive a movable optical display plate 16.

The movable display plate 16 has two downwardly extending lateral extensions 17 which enclose a groove 18. In each case one end of the fork tine 7 of the shift fork 6 engages in the groove 18 in order to change the position of the display plate 16 by moving and pulling during the separation process. Here, an upper portion of the mounting leg 15 is released, which serves as a so-called red indicator 19 (error display).

The optical display plate 16 is preferably made of a green colored plastic material and thus symbolizes the "green display", i. the proper condition. The change in the color position green / red can be seen through a window, not shown, of an outer housing, not shown.

In the housing bottom 3 is still a known coding pin 20 can be used to prevent erroneous placement of a (not shown) base part.

The presented separating device thus consists essentially of a U-shaped shift fork, which establishes the electrical contact between the Varistoranschlussfahnen and the outer plug contact.

The connection of the varistor terminal lugs to the shift fork and the shift fork to the plug contact together with a low-melting solder the separation points. The separating sled, in the space between Caseback and varistor unit is placed, engages by means of claws the outer ends of the shift fork. The separation takes place after melting of the solder joints by the spring biasing force whose force vector acts between the separation slide and the housing bottom. By triggering the separation slide a recess on the underside of the male part is released, which leads to the raising of a push pin (not shown) and switching a telecommunications device in the lower part. When the separation point is opened by the separation slide, the shift fork performs a rotary movement in which the lower edges of the varistor connection lugs virtually act as axes of rotation. The over the Varistoranschlussfahnen out projecting upper forks 7 serve as a driver for the optical display plate 16 by the corresponding fork tines engage in the groove 18.

LIST OF REFERENCE NUMBERS

1

varistor

2

Stop edges / connection contact

3

caseback

4

Clamp or plug contact

5

connection port

6

shift fork

7

forks

8th

section

9

claw-like section

10

separating slide

11

compression spring

12

pivot point

13

guide

14

insulating

15

fastening leg

16

optical display plate

17

extension

18

groove

19

Rotanzeige

20

Polarizing

Claims (13)

1. Overvoltage protection device having one or more parallel-connected overvoltage-limiting elements, which are located in one physical unit, such as varistors, diodes or means of this type configured in the form of a disc, comprising a switching device in order to electrically disconnect the overvoltage-limiting elements when they are thermally overloaded, and means for indicating and/or reporting the fault condition which then occurs, wherein the switching device is connected via a thermally separable means, such as an adhesive or a solder, to a connecting contact of the at least one overvoltage-limiting element and/or to an external clip contact or plug contact, and wherein the at least one connecting contact is located on one of the side faces of the overvoltage-limiting element configured in the form of a disc,
   characterized in that
   the switching apparatus is in the form of a solid U-shaped switching fork (6), the fork tines (7) of which run essentially parallel to the side faces of the overvoltage-limiting element (1) and receive the latter in the space between the tines,
   furthermore the section (5) connecting the fork tines (7) is electrically connected to one of the external clip or plug contacts (4) and rests on a separating slide (10) which comprises at least one claw-type section (9) encompassing the end of the switching fork (6) located there,
   the separating slide (10) is subjected to a spring force preload, wherein the force vector in this regard is oriented to face away from the point of connection between the switching fork (6) and the external clip or plug contact (4), at least one of the fork tines (7) lies against the at least one connecting contact (2), where it is fixed by the thermally separable means, wherein, in the event of a disconnection, the separating slide (10) moves by carrying along the switching fork (6), with the point of connection between the fork tines (7) and the connecting contact (2) representing a fulcrum (12) with respect to the movement of the switching fork.
2. Overvoltage protection device according to claim 1,
   characterized in that
   the overvoltage-limiting elements are comprised of at least two varistor discs, which are arranged in parallel, and that a first connecting contact (2) is located on one of these side faces, wherein the additional second connecting contacts (5) are connected to the additional ones of the external clip or plug contacts (4) and the respective fork tines (7) of the switching fork (6) are each fixed to one of the first connecting contacts (2) by the thermally separable means, wherein occurring currents flow through the fork tines (7) in the parallel direction.
3. Overvoltage protection device according to claim 1 or 2,
   characterized in that
   the separating slide (10) is mounted in a guide (13) which forms part of the bottom (3) of a housing receiving the protection device.
4. Overvoltage protection device according to claim 3,
   characterized in that
   the separating slide (10) is movably guided parallel to the housing bottom (3) between openings located there for receiving the clip or plug contacts (4).
5. Overvoltage protection device according to claim 3 or 4,
   characterized in that
   the claw-type sections (9) of the separating slide (10) extend from the housing bottom (3) in an upward direction.
6. Overvoltage protection device according to one of claims 3 to 5,
   characterized in that
   the disc-shaped overvoltage-limiting element(s) extend(s) substantially perpendicular to the housing bottom (3) in an upward direction.
7. Overvoltage protection device according to claim 6,
   characterized in that
   an insulating bearing part or an insulating cover (14) is provided between the separating slide (10) and the disc-shaped overvoltage-limiting elements (1).
8. Overvoltage protection device according to one of claims 3 to 7,
   characterized in that
   a fixing leg (15) for receiving a movable optical display panel (16) extends over a longitudinal outer edge of the disc-shaped overvoltage-limiting elements (1) by partially encompassing the latter.
9. Overvoltage protection device according to claim 8,
   characterized in that
   the movable display panel (16) comprises at least one lateral prolongation (17) with a groove (18), wherein one end of the fork tine (7) of the switching fork (6) engages the groove (18) so as to change the position of the display panel (16) during the disconnection process.
10. Overvoltage protection device according to one of claims 3 to 9,
    characterized in that
    an opening for receiving a pin is located in the housing bottom (3), which actuates or triggers a remote fault indicating device depending on the position of the separating slide (10).
11. Overvoltage protection device according to one of the preceding claims,
    characterized in that
    the connecting contacts (2) on the side faces of the overvoltage-limiting elements (1) are configured as strip-shaped stop edges projecting from the side face plane.
12. Overvoltage protection device according to one of the preceding claims,
    characterized in that
    the thermally separable means connect the fork tines (7) to the connecting contacts (2) on the overvoltage-limiting elements (1) as well as the section (8) connecting the fork tines (7) to the corresponding external clip or plug contact (4).
13. Overvoltage protection device according to claim 11,
    characterized in that
    the ends of the stop edges facing in the direction of the housing bottom (3) of the assembly define the fulcrum (12) for the movement of the switching fork (6) during the disconnection process.

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