Surge protection device, comprising at least one surge arrester and one thermally trippable switching device connected in series with the surge arrester

Abstract

The invention relates to a surge protection device, comprising at least one surge arrester and one thermally trippable switching device connected in series with the surge arrester, wherein the above-mentioned means form a structural unit and the thermal tripping means is arranged in the region in which heating of the surge arrester is to be expected on overloading thereof. The thermal tripping means is in the form of a stop part through which there is no operating or surge current flowing and which effects or enables unlatching of the switching device in the case of thermal overload. Furthermore, the stop part is coupled thermally and mechanically to a surface side of the surge arrester and blocks the movement path of a mechanically prestressed unlatching slide. In accordance with the invention, a contact platelet is inserted in the unlatching slide, said contact platelet producing an electrical connection between elements of the switching device and, with unlatching, the contact platelet is subjected to a shifting movement resulting in an interruption to the series circuit and movement of the unlatching slide into the space previously assumed by the contact platelet, wherein at least the section of that region of the unlatching slide which separates the elements of the switching device is insulating.

Claims

1. A surge protection device, comprising at least one surge arrester (1) and one thermally trippable switching device (9; 10; 11) connected in series with the surge arrester (1), wherein the at least one surge arrester and one thermally trippable switching device form a structural unit and a thermal tripping means (4K) is arranged in the region in which heating of the surge arrester (1) is to be expected on overloading thereof, wherein the thermal tripping means (4K) is formed as a stop part through which no operating or surge current flows and which releases unlatching of the switching device in the case of thermal overload, wherein the stop part (4K) is further coupled thermally and mechanically to a surface side (2) of the surge arrester (1) and blocks the movement path of a mechanically prestressed unlatching slide (6), wherein the thermally trippable switching device comprises at least a first element 9, a second element 10 and a third element 11, wherein a contact platelet (111) is inserted into the unlatching slide (6), said contact platelet producing an electrical connection between the second element (10) and the third element (11) of the switching device, wherein the contact platelet (111), with unlatching, is subjected to a shifting movement resulting in an interruption to the series circuit of the switching device and movement of the unlatching slide (6) into the space previously assumed by the contact platelet (111), wherein at least the section of the region of the unlatching slide which separates the second element (10) and the third element (11) of the switching device is formed in an insulating manner, characterized in that the third element (11) of the switching device is formed as a pin or bolt, which is mechanically prestressed in the direction of the second element (10), wherein the first element (9) is a connection bracket, wherein the second element (10) is a counter-contact which is electrically connected to the connection surface of the surge arrester (1), wherein the pin or bolt is connected to the connection bracket, and a rocker (XX) having elastic properties is provided, which is mounted with a first rocker end on a fixed point (X1) and acts with a second rocker end on a movable stop (X2).

2. A surge protection device according to claim 1, characterized in that the movable stop (X2) is part of a swivel arm (4), wherein the swivel arm (4) comprises a formed portion (X3) which rests on the stop part (4K).

3. A surge protection device according to claim 2, characterized in that the unlatching slide (6) comprises a blocking arm (X4), which in the non-tripped state is blocked by the swivel arm (4).

4. A surge protection device according to claim 3, characterized in that the swivel arm (4) comprises a guide recess (41) for an axle pin, wherein the pivoting movement can be carried out about the axle pin.

5. A surge protection device according to claim 2, characterized in that the swivel arm (4) comprises a pin protrusion (42) which penetrates a recess in the base of the housing and interacts with a fault communications device.

6. A surge protection device according to claim 1, characterized in that the unlatching slide (6) is movably mounted in a guide part (3), wherein the guide part (3) comprises a space for accommodating a spring (61).

7. A surge protection device according to claim 3, characterized in that the unlatching slide (6) comprises a state indicator surface (62).

8. A surge protection device according to claim 1, characterized in that the surge arrester is a varistor which comprises a surface side (2) having metallic, conductive properties and from which a surface portion extends which forms the counter-contact (10).

9. A surge protection device according to claim 1, characterized in that a further connection bracket (92) is connected to a contact (93) of the surge arrester (1).

10. A surge protection device according to claim 1, characterized in that fixing surfaces (94) are disposed on the surge arrester (1) which engage in complementary recesses of a housing part.

Description

(1) The invention will be explained below in closer detail by reference to an embodiment shown in the drawings, wherein:

(2) FIG. 1 shows a highly simplified, principal configuration of the solution in accordance with the invention in the normal functional state (FIG. 1) and in the cut-off state (FIG. 2), and

(3) FIGS. 3 and 4 show a perspective view of the relevant functional elements of the surge protection device in accordance with the invention in the operating state (FIG. 3) and in the cut-off state (FIG. 4), wherein the illustrations according to FIGS. 3 and 4 omit the housing and parts of the housing which finally form the plug-in part for reasons of clarity of the illustration.

(4) As is shown in FIGS. 1 and 2, the surge protection device in accordance with the invention consists first of all of a surge arrester 1, especially a varistor 1, having a respective surface side 2.

(5) A stop part 4K is fixed to the surface side 2 of the varistor 1. Said stop part 4K is fixed by means of a solder for example to the respective surface side 2. When the varistor 1 has a specific temperature which exceeds the permissible operating temperature, the solder melts which connects the stop part 4K to the surface side 2. The stop part 4K then performs a movement in the direction of the arrow.

(6) An unlatching slide 6 is displaceably mounted within a guide part 3, wherein the unlatching slide 6 is under the prestress of a spring 61. The prestress of the spring ensures that the unlatching slide 6 moves to the right relating to FIGS. 1 to 4 when there is no limit stop. This is symbolised with respective displays of arrows within the part 6 in FIGS. 1 and 2.

(7) Furthermore, FIGS. 1 and 2 show the actual switching device, comprising the parts 9, 10 and 11.

(8) A first element is formed as a pin or bolt 11, which is under mechanical prestress, symbolised by the spring XX, in the direction of the further element 10. Said further element 10 forms a counter-contact which is electrically connected to the connection side 2 or the respective surface side and a conductive part of the surge arrester 1 which is present there.

(9) The part 9 can simultaneously form the connecting bracket or a plug-in contact with a bottom end shown in the drawings.

(10) In the normal operating state according to claim 1, the current path is closed via the parts 9, 11, 111 and 10. The part 111 is preferably a contact platelet, which is embedded in a respective recess of the unlatching slide 6. Said contact platelet 111 thus produces the desired connection between the connection bracket 9 and the counter-contact 10, which is in connection with the varistor.

(11) If the permissible operating temperature was exceeded, the stop part or tripping means 4K is released and then reaches a position similar to the one shown in FIG. 2. The unlatching slide 6 can thus move to the right in the direction of the image. The consequence is that the contact platelet 111 is also pushed out of the current path to the right. An insulating section of the unlatching slide now enters the freed-up intermediate space instead of the contact platelet and ensures a very high self-quenching capacity. The respective section of the unlatching slide 6 can consist of a gas-emitting material such as POM, which improves the quenching properties and prevents the production of arcs.

(12) Since the thermal tripping means 4K has left its original position according to FIG. 2, the swivel arm 4 can move to the right according to the shown illustration of the arrow. In this process, the prestressing force also loses its effect by means of the symbolically shown spring XX.

(13) In the case of a realised form of the invention as shown in FIGS. 3 and 4, a rocker XX is present which has elastic properties. The rocker produces a respective prestress, which is still symbolised in FIGS. 1 and 2 by the illustrated spring. A first rocker end is mounted on a fixed point X1. A second rocker end acts on the movable stop X2 of the swivel arm 4.

(14) The movable stop X2 is therefore a part of the swivel arm 4, wherein the swivel arm 4 further comprises a formed portion X3 (see FIGS. 3 and 4) which rests on the stop part or tripping means 4K.

(15) The unlatching slide 6 further comprises a locking arm X4, which in the non-tripped state is blocked by the swivel arm 4 and the end that is still present there, which is especially shown in FIG. 3.

(16) The swivel arm 4 comprises a guide recess 41 for an axle pin (not shown in the drawings), wherein the pivoting movement of the swivel arm 4 can be carried out about the axle pin.

(17) The swivel arm 4 further comprises a pin protrusion 42, which penetrates a recess in the base of the housing (not shown) and can interact with a fault communications device (also not shown).

(18) It is shown in FIGS. 3 and 4 that the unlatching slide 6 is movably mounted in the guide part 3, wherein the guide part 3 comprises a space for accommodating the spring 61.

(19) FIGS. 3 and 4 also show the state indicator surface 62, which is formed on or integrally attached to the unlatching slide 6.

(20) A further connection bracket 92, whose bottom end forms one of the plug-in contacts of the plug-in part and which accommodates the surge protection device, is in connection with a further contact 93 of the surge arrester 1.

(21) The surge arrester 1 comprises several fixing surfaces 94, which are formed as metallic bent sections for example which engage in complementary recesses of a housing part (not shown) and hold the varistor there.