EP2294589B1 - Overvoltage protection device with a thermal disconnection apparatus - Google Patents

Description

The invention relates to an overvoltage protection device with thermal separation device and fault indication and a plurality, in particular disc-shaped varistors, each Ableitpfad at least one varistor is associated and the thermal separation points in series with the respective varistor, a device housing with chambers for receiving the varistors and a pivotally mounted lever with a display surface, which is located in the region of a housing window, through the housing bottom reaching plug-in connections to make an electrical connection to a base part, further wherein the thermal separation points each comprise a spring-biased bracket which electrically and mechanically connected to a low-melting solder with the respective varistor is, according to the preamble of claim 1.

From the German utility model DE 295 19 313 An overvoltage protection device with thermal cut-off device is previously known. Another overvoltage protection device is in document WO200715066 described.

The local surge arrester has a lower part which is electrically connected to inlets and outlets of the system to be protected or the device to be protected. Furthermore, a plug-in part is present, which has at least one varistor. The male part is detachable by a mechanical plug connection with the lower part and thereby electrically connected, wherein on the male part a thermal release is provided in the event of inadmissible heating of the varistor.

In the male part, a support wall is provided, wherein the varistor are attached to a side surface of the support wall and the thermal separation device and corresponding switching means on the other side surface of the support wall. The thermal tripping is thus opposite the varistor.

The known plug-in part is formed trough-shaped, wherein the bottom of the tub forms the aforementioned support wall and the tub edge the area next to surrounds the supporting wall, in which there is mounted on the supporting wall varistor. The varistor itself is equipped with two terminal lugs, which serve the electrical connection, with a terminal lug is in communication with the thermal release element.

In the surge protector after EP 0 727 091 B1 two or more accommodated in a housing varistors are present as protective elements, the ground-line side electrodes are electrically conductively connected to each other by a bar with a contact piece. The network-side electrodes are connected to contact pieces via cut-off devices connected in series with protective elements.

According to the EP 0 727 091 the task should be solved to simplify the separation device constructively, without the protective properties are adversely affected.
For this purpose, all separating devices in the pivot region of the web of a pivotally mounted in the housing, substantially U-shaped, designed as a rocker bracket are arranged. At the bridge a slidably mounted in the housing actuating pin is adjacent and continue on the bracket, a display device is arranged. Characterized in that all separating devices, which are assigned in the overvoltage protection built protection elements, a common rocker is assigned, the construction is simplified according to the task. In addition, it is ensured that when opening, ie when triggering the separating device, that is, even when triggering only a separating device, the actuating pin is moved and the trigger indicator device comes into a position that makes it clear that a replacement of the surge protection device is necessary.

The protective elements after EP 0 727 091 are used in provided in a housing part of the overvoltage protection device, upwardly open chambers and surrounded in these chambers with a potting compound. The separating device is held under tension by means of a compression spring.

In the device for protection against the occurrence of transient electrical overvoltages according to EP 0 716 493 B1 At least two varistors are present and there are also provided separating means which are against the state the varistors are sensitive, especially in thermal terms. Each of the varistors can be separated individually.

In addition, there are mechanical means for visualizing the state of the varistors which are operatively connected to the separating means for actuation therewith. The mechanical visualization means comprise a rotor, which is actuated by separating tongues of two varistors mounted in parallel, wherein the rotor has two steps with driving fingers, one of which is rigid and more fingers are flexible.

All previously known solutions of the prior art have in common that the separation devices must have more or less complex, additional mechanical and electrical means. This increases the number of parts and overall design complexity in the production of surge protection devices. A large number of parts inevitably leads to a higher installation effort, which must be avoided in principle.

From the foregoing, it is therefore an object of the invention to provide a further developed overvoltage protection device with thermal disconnecting device and fault indication, which has a plurality of varistors and wherein in each varistor path the possibility of separation in case of overload is created and also a visualization of the state in question can take place.

The separation device for the overvoltage protection device should be designed so that in a particularly advantageous manner commercially wired Scheibenvaristoren can be used.

The object of the invention is achieved by the surge protection device according to 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 thermal disconnecting device and fault indication, which has a plurality of, in particular disc-shaped varistors. Each discharge path is assigned at least one varistor and the thermal separation points are each in series to the relevant varistor. Furthermore, a device housing with chambers for receiving the varistors is present. A pivotally mounted bracket has a display surface which is located in the region of a housing window to visualize a fault or an ok condition. Through the housing bottom plug-in connections rich enough to establish an electrical connection to a base part. Furthermore, the thermal separation points each comprise a spring-biased bracket, which is electrically and mechanically connected to the respective varistor with a low-melting solder.

According to the invention, the spring-biased stirrups are formed by a single stamped and bent part which, starting from a common connecting leg, has finger-like extensions corresponding to the number of separating points.

At least one plug connection is provided at the connecting leg, which leads through the housing bottom and forms an external connection to the aforementioned base part.

The finger-like extensions have in the region of their free end a slot-shaped recess, in each of which a connection wire or a connecting leg of a varistor is soldered directly. In the area behind the solder joint in the direction of the connecting leg, a heat trap is located, wherein each finger-like extension is acted upon by a separate spring force. In a preferred embodiment, a connecting leg or a connecting wire of the relevant varistor is bent in a U-shape and soldered to the U-leg in the slot-shaped recess. The closed leg points to the finger-like extension and the leg end to the top.

The pivotally mounted error display lever has a lever arm which engages in a space below the finger-like projections to be entrained in the separation process by the respective moving extension, i. to be pressed.

The pivotally mounted lever is held by a spring element in a desired position, wherein the spring biasing force of the relevant thermal separation points is greater than the holding force of the spring element of the Lever. This holding force only serves to hold the display surface in its initial position, as long as a fault-free state is present.

Each finger-like projection has a bore for receiving a guide pin, wherein a helical spring is arranged on the guide pin, which on the one hand is supported against a clamping device and on the other hand exerts the desired spring force on the finger-like extension.

The tensioner is releasably connected to the housing.

In this way, first the soldering of the varistors can be done with the finger-like extensions and then the tensioning device can be used with the springs, which represents a considerable ease of assembly.

The tensioning device comprises the aforementioned guide pins, wherein an edge of the tensioning device engages in claw-like projections of the chambers, which are part of the housing. By this locking a secure fixing of the clamping device is ensured.

Ausgestaltend a contact point for the attachment of another arrester, in particular a gas discharge can be formed on the connecting leg.

The pivotable lever comprises in a preferred embodiment, a pin which engages in a recess of the housing bottom to operate in the fault or separation case located in the base part telecommunications switch.

The spring element for the positioning of the pivotally mounted lever is preferably a bending spring, which is supported with one end on the housing and which is inserted with its other end into a recess in the lever.

The pivotable lever is oriented or arranged on one side of the housing and the chambers on the opposite side of the housing, so that a separate mounting of the lever after insertion and soldering of the varistors can be carried out. This also makes it easier to assemble.

The respective heat trap, which is located on the finger-like projections, is preferably formed as a transversely to the longitudinal extent of the respective finger-like projection realized recess.

The finger-like extensions have a embossing point for targeted bending, in the transition region connecting leg / respective finger-like extension.

Slot-shaped clamps or claws extend in the direction of the housing interior from the housing bottom, wherein the connecting limb is inserted and fixed in the slots. This measure also serves to facilitate the installation of the overvoltage protection device.

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

Fig. 1

eine Seitenansicht des Überspannungsschutzgeräts (Steckteils) mit abgenommener Gehäusekappe und erkennbarer Kammer mit Varistorscheibe;

Fig. 2

eine weitere Seitenansicht, die derjenigen nach Fig. 1 gegenüberliegt, mit dem schwenkbeweglich gelagerten Hebel, dessen Hebelarm in den Raum unterhalb der fingerartigen Fortsätze eingreift;

Fig. 3

eine Draufsicht auf das Überspannungsschutzgerät ohne Gehäusekappe mit den erkennbaren Kammern und darin aufgenommenen, bereits verlöteten Varistoren;

Fig. 4

eine Detaildarstellung des schwenkbeweglich gelagerten Hebels mit Hebelarm und Anzeigefläche und

Fig. 5

das noch nicht an den Prägestellen abgewinkelte Stanzteil, welches aus einem Verbindungsschenkel und im gezeigten Beispiel drei fingerartigen Fortsätzen, einer Kontaktstelle für einen Gasableiter und einem Kontakt für elektrischen Anschluss zum Unterteil (Basisteil) besteht.

Hereby show:

Fig. 1

a side view of the surge protection device (plug-in part) with removed housing cap and recognizable chamber with varistor disc;

Fig. 2

another side view, the one after Fig. 1 opposite, with the pivotally mounted lever whose lever arm engages in the space below the finger-like projections;

Fig. 3

a plan view of the surge protective device without housing cap with the recognizable chambers and accommodated therein, already soldered varistors;

Fig. 4

a detailed view of the pivotally mounted lever with lever arm and display surface and

Fig. 5

the not yet angled at the embossing points punched part, which consists of a connecting leg and in the example shown three finger-like extensions, a contact point for a gas arrester and a contact for electrical connection to the lower part (base part).

That in the Fig. 1 to 3 Surge protection device shown without housing cap consists of a housing 1, which has a plurality of chambers with chamber walls 2.

The given between the chamber walls 2 spaces take on disc-shaped varistors 3. In the illustrated example, an overvoltage protection device with three varistors 3 and an additional gas arrester 4 is shown, wherein the gas arrester is connected in parallel with the varistors for the phases L1, L2 and L3 in series and clamped on PE.

The housing bottom 5 penetrate various plug-in connections 6 in order to produce an electrical connection to the base part (not shown).

The varistors 3 have common wire connections. One of the wire terminals 7 is bent in a U-shape and engages with its U-connection leg in a recess 8 in each case a finger-like projection 9 a.

In the region of the recess 8, a soldering with the finger-like projection 9 takes place. This Lotstelle forms the thermal separation point of the separation device.

In the device housing is still a pivotally mounted lever 10 is located, which has a display surface 11 which is associated with a viewing window in the housing cap, not shown.

The pivotally mounted lever 10 is guided by a stub axle 12. For this purpose, a bore 13 is present in the lever 10.

Springs 14 provide the necessary bias of the finger-like projection 9 and thus a force on the solder separation point in the region of the recess. 8

The spring-biased extensions or bracket 9 are by punched and bent parts (see Fig. 5 ), which, starting from a common connecting leg 15, have the finger-like extensions 9. On the connecting leg 15, one of the plug-in connections 6 can be formed.

The finger-like extensions 9 have, in the region of their free end, the slot-like recess 8 already mentioned, into which in each case directly a connecting wire or a connection leg of a varistor 3 is soldered.

In the area behind the solder joint in the direction of connecting leg 15, a heat trap 16 is located in the form of a transverse punched. Embossing 17 serve the targeted bending of the stamped part, so that it in the Fig. 1 and 3 recognizable form receives.

The punched-bent part may still have a special contact point 18 to contact the gas discharge tube 4 by soldering.

The pivotally mounted lever 10 has a lever arm 19 (see Fig. 4 ), which in a space below the finger-like projections 9 (see Fig. 2 ) engages to be taken during the separation process by the respective moving extension and in the illustration according to Fig. 2 to pivot the lever to the right. During this pivoting to the right, the display surface 11 leaves its position and it is an underlying, color differently represented field released to optically signal the error condition.

The pivotally mounted lever 10 is held by a spring element 20 in the form of a spiral spring in a desired position, wherein the spring biasing force of this bending spring is smaller than the spring biasing force of the respective thermal separation points.

Each of the finger-like extensions 9 has a bore 21 which serves to receive a guide pin 22.

On the guide pin 22 one of the coil springs 14 is attached, which is supported against a clamping device 23 which is detachably connected to the housing 1.

In the example shown after Fig. 1 and 2 the tensioning device 23 on three guide pins for three finger-like extensions 9, wherein each guide pin 22 receives a coil spring 14.

An edge 24 of the clamping device 23 engages in claw-like projections 25, which are integrally formed on the chambers or chamber walls 2.

The pivoting lever 10 has a pin 26 which engages in a recess 27 in the housing base 5 in order to operate in the fault or separation case located in the base part (not shown) remote switch.

The spiral spring element 20 is supported at its one end on the housing or as shown on the clamping device 23 and is inserted with its other end into a recess in the lever 10 and thereby guided safely.

From the side views to the Fig. 1 and 2 It is clear that the pivoting lever 10 are arranged on one of the housing sides and the chambers on the other side of the housing, so that a separate mounting of the lever 10 after insertion and soldering of the varistors 3 can take place.

It is clear from the explanations on the exemplary embodiment that three (but also several) separating devices can be realized by a single stamped and bent part. In addition to the function of separating, the stamped part also provides the electrical connection to the lower part and may comprise a contact point for a further arrester, in particular a gas discharge tube.

The configuration of the finger-like extension, in conjunction with a varistor lead formed on the application and using a low temperature solder, allows for a very sensitive cutoff location. A particular advantage is that a use of commercially available wired Scheibenvaristoren is possible.

The display is realized with little mechanical effort and responds to the independently acting separating devices in the sense of an OR operation. In addition to the display function, the display block or the lever also fulfills the option of controlling a telecommunications contact. The actual separating device consists, as explained, of a sheet metal part with at least three finger-like extensions (separating strips), an extension for an electrical connection to the lower part in the form of a fork contact and, optionally, a contact point for a gas discharge tube.

Each separation strip forms the electrical contact with each of a varistor and is equipped with a stamping for flexibility. The separation strip also has a guide hole for the tensioning device and a transverse slot as a heat trap and a longitudinal slot for receiving the varistor connection wire.

The longitudinal slot forms a connection with a loop-shaped varistor connecting wire and a low-melting solder the separation point. The bias of the tensioning device causes the separation of the varistor from the separation strip during melting of the solder, which in turn actuates the display block via the lever.

LIST OF REFERENCE NUMBERS

1

casing

2

chamber wall

3

varistor

4

gas arrester

5

caseback

6

plug-in connection

7

wire connection

8th

recess

9

finger-like extension

10

lever

11

display area

12

stub axle

13

Hole in the lever

14

feather

15

connecting leg

16

heat trap

17

embossing location

18

contact point

19

lever arm

20

spring element

21

drilling

22

guide pin

23

jig

24

edge

25

claw-like projections

26

pen

27

recess

Claims (12)

1. An overvoltage protection device having a thermal disconnection apparatus and an error display as well as a plurality of particularly disc-shaped varistors (3), wherein each discharge path is associated with at least one varistor (3) and the thermal disconnection points are positioned in series to the respective varistor (3), a device housing (1) comprising chambers for accommodating the varistors (3) and a pivotably mounted lever (10) having a display area (11) situated in the region of a housing window, plug connections (6) extending through the housing base (5) for establishing an electrical connection to a base part, wherein the thermal disconnection points each further comprise a spring-preloaded bracket electrically and mechanically connected to the respective varistor by a low-melt solder,
   characterized in that
   the spring-preloaded brackets are formed by a stamped and bent part comprising finger-like extensions (9) extending from a common connecting limb (15) and wherein at least one plug connection (6) is provided on the connecting limb, the finger-like extensions (9) have a slotted recess (8) at their free end in which a respective connecting wire or connecting leg (7) of a varistor (3) is directly soldered as well as a heat trap (16) situated in the region behind the soldering point toward the connecting limb, wherein each finger-like extension is acted upon by a separate spring force (14).
2. The overvoltage protection device according to claim 1,
   characterized in that
   the pivotably mounted lever (10) comprises a lever arm (19) which engages into a space beneath the finger-like extensions (9) in order to be carried along by the respectively moving extension during the disconnecting process.
3. The overvoltage protection device according to claim 2,
   characterized in that
   the pivotably mounted lever (10) is held in a set position by a spring element (20), wherein the spring preload force of the thermal disconnection point is greater than the retention force of the lever's spring element.
4. The overvoltage protection device according to any one of the preceding claims,
   characterized in that
   each finger-like extension (9) comprises a drill hole (21) for receiving a guide pin (22), wherein a helical spring (14) braced against a tensioner (23) detachably connected to the device housing (1) is arranged on the guide pin (22).
5. The overvoltage protection device according to claim 4,
   characterized in that
   the tensioner (23) clasps the guide pins (22), wherein an edge of the tensioner (23) latches into claw-like projections (25) of the chambers (2).
6. The overvoltage protection device according to any one of the preceding claims,
   characterized in that
   a contact point (18) for a further diverter, particularly a gas discharge tube, is integrally formed on the connecting limb (15).
7. The overvoltage protection device according to any one of the preceding claims,
   characterized in that
   the pivotable lever (10) comprises a pin which engages in a recess of the housing base so as to activate or trigger a remote signaling switch situated in the base part in the event of failure or disconnection.
8. The overvoltage protection device according to claim 3,
   characterized in that
   the spring element is a flexible spring (20) with one end braced against the housing (1) and its other end inserted into a recess in the lever.
9. The overvoltage protection device according to any one of the preceding claims,
   characterized in that
   the pivotable lever (10) is arranged on one side of the housing and the chambers on the other side of the housing to enable the lever to be separately mounted after the insertion and soldering of the varistors.
10. The overvoltage protection device according to any one of the preceding claims,
    characterized in that
    the respective heat trap is configured as a recess (16) running transverse to the longitudinal extension of the finger-like extensions (9).
11. The overvoltage protection device according to any one of the preceding claims,
    characterized in that
    the finger-like extensions (9) have a stamping area (17) for selective bending.
12. The overvoltage protection device according to any one of the preceding claims,
    characterized in that
    slotted clamps extend from the housing base into the interior of the housing, wherein the connecting limbs are inserted into and fixed by the slots.

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