Device for thermally tripping or disconnecting an overvoltage protection device

Abstract

The invention relates to a device for thermally disconnecting or tripping an overvoltage protection device, comprising: a locking element (A1), on which a first force (F1) acts, and which is fixed in such a way that same is released when a limit temperature is exceeded; and a slider (S1) which is blocked in a first state (Z1) by the fixed locking element (A1), and on which a second force (F2) acts in order to transfer same into a second state (Z2) when the locking element (A1) is released.

Claims

1. A device for thermally tripping or disconnecting an overvoltage protection device, comprising: a locking element (A1) on which a first force (F1) acts and which is fixed to the device in such a way that said locking element is released when a limit temperature is exceeded, wherein the temperature-dependent fixing of the locking element (A1) is realised by a solder connection, an adhesive and/or by a wax connection; a slider (S1) which is blocked in a first state (Z1) by the fixed locking element (A1), and on which a second force (Z2) acts in order to transfer said slide to a second state (Z2) when the locking element (A1) is released; characterized by a latching-holding device (H1) which is connected to the slider (S1) and by means of which the locking element (A1), which is configured as an electrical component and is fixed to a circuit board, blocks the slider indirectly and by means of which the second force (F2) only acts as a partial force component in a frictionally engaged clamping manner on the locking element (A1), wherein the latching-holding device (H1) comprises at least two elastic, resilient jaws (B) which are supported in the first state (Z1) against the fixed locking element (A1) and against a surrounding area (G) of the slider (S1), the jaws (B) further each comprising an outwardly directed groove for accommodating one cam (H2) each, the second force (F2) being redirected by the cams (H2) onto the jaws (B) in order to press the jaws (B) inwardly.

2. A device according to claim 1, characterized in that the first force (F1) and/or the second force (F2) is produced by a pretensioned spring and/or by a mass.

3. A device according to claim 1, characterized by a wedge-shaped fin (S) which lifts the locking element (A1) relative to its surrounding area (G) on which it is fixed in the first state (Z1) when it is pressed against the wedge-shaped fin (S) during transfer into the second state (Z2).

4. A device according to claim 1, characterized in that the force-generating elements are arranged in such a way that the first force (F1) and the second force (F2) are directed in parallel to each other and F1F2.

Description

(1) Features of different embodiments can be combined with each other advantageously in further embodiments that are not shown. Further advantages and features are provided in the dependent claims and the embodiments, which are shown in the drawings in a partly schematic way:

(2) FIG. 1 shows an embodiment in accordance with the invention in a first state;

(3) FIG. 2 shows an embodiment in accordance with the invention with a released locking element;

(4) FIG. 3 shows an embodiment in accordance with the invention during transition to the second state;

(5) FIG. 4 shows an embodiment in accordance with the invention in a second state, and

(6) FIG. 5 shows an embodiment of the invention that has been realised in practice.

(7) FIG. 1 shows a device for thermally tripping or disconnecting an overvoltage protection device, comprising a display surface and a slider (S1) in the first state (Z1). A force (F2) is applied to said slider by a coil spring. The coil spring is supported for this purpose on a housing (G) in which the slider (S1) is mounted. The coil spring is used as an energy storage unit, wherein the force (F2) is high enough to move the slider (S1). The slider (S1) comprises a holding device which is realised by two opposite jaws (B).

(8) A locking element (A1) in form of a varistor for example is further fixed to a circuit board (L). The fixing occurs via solder connections (not shown) on two metallic conductor tracks (R) which hold the locking element (A1) at the front and the back and make contact with said element.

(9) The jaws (B) of the holding device (H1) are formed in a resilient manner, especially consisting of a flexible plastic material. The jaws (B) further each comprise an outwardly oriented groove. They are used to respectively accommodate a cam (H2) which is realised as a part of the housing (G). The slider (S1) is pressed in the direction of the locking element (A1) by the second force (F2). This force is diverted to the jaws (B) by the cams (H2) which engage in the groove of the jaws (B) in such a way that they are pressed inwardly.

(10) A yielding of the jaws (B) to the inside is prevented by the locking element (A1) however, which is arranged between the ends of the jaws (B). A movement of the jaws (B) towards each other is thus prevented and therefore also a movement of the slider (S1). In this first state in which the locking element (A1) is tightly fixed to the wiring support, the locking element (A1) prevents a movement of the jaws (B) of the slider towards each other. The pincers of the jaws can therefore not be pressed together. A movement of the slider is prevented by the latched connection (H1; H2).

(11) The normal forces compensate each other by the oppositely arranged jaws (B), which normal forces are applied via the jaws (B) by the second force (F2) to the holding device (H1). This leads to the result that the resulting normal force on the locking element (A1) disappears. The second force (F2) is thus decoupled from a direct effect on the locking element (A1) in the first state.

(12) FIG. 2 shows the device for the thermal tripping of an overvoltage protection device of FIG. 1. The fixing of the locking element (A1) has been released by exceeding a limit temperature and the device moves to the second state (Z2).

(13) A spring is disposed between the jaws (B), which is supported on the slider (S1) and directly exerts a first force (F1) on the locking element (A1) in a pretensioned state. This force leads to an acceleration of the locking element (A1) when it has been released from fixing. The spring is dimensioned and the first force (F1) on the locking element (A1) is just proportioned in such a way that the intended effect occurs, i.e. the acceleration of the locking element (A1) after the release of the fixing.

(14) FIG. 3 shows the device according to FIGS. 1 and 2, wherein the transfer of the state is in a second phase. The locking element (A1) was pressed out of the jaws (B) by the first force (F1). The jaws (B) of the holding devices can thus move to the inside. The jaws (B) are pressed inwardly by the second force (F2) via the latching means, especially by the cams of the housing, so that the right side of the groove of the jaws (B) no longer blocks a movement of the slider (S1). The latched connection (H1) is thus overcome. The second force (F2) accelerates the slider (S1) and thus also moves the display surface (A) to the left. This indicates a tripping of the overvoltage protection device for example.

(15) A fin (S) is situated in the drawing on the left side adjacent to the fixing of the locking element (A1), which fin is used to lift the locking element (A1) from its fixing and to especially completely separate the same. This occurs in such a way that the locking element (A1) is pushed by the first force (F1) onto the fin (S). It is ensured by this complete separation that the electrical connection which occurs by the fixing is also completely interrupted and thus the electric circuit closed thereby is also interrupted. In particular, the formation of an arc is thus also excluded.

(16) FIG. 4 shows the device according to FIGS. 1, 2 and 3 in the second state (Z2). The slider (S1) is moved completely to the left. The flexible jaws (B) of the holding device (H1) are in their initial form again. The locking element (A1) is accelerated via the fin (S) away from the fixing and the wiring support, especially the live conductor tracks (R). The force (F2) acts in a supporting manner in this case.

(17) FIG. 5 shows a view of a practically realised embodiment of the invention with a housing (G) which is partly broken away. This embodiment concerns a device for overvoltage protection, wherein at least one varistor (V) is used as an overvoltage protection element. Said varistor (V) is situated within the housing (G). The actual device for thermally tripping and disconnecting the varistor (V) is also integrated in the housing (G).

(18) The locking element (A1) is also situated in this embodiment on a circuit board (L) and makes contact there with the existing conductor tracks and connecting surfaces (not shown in the drawing), especially by soldering. The slider (S1) is subject to the pretensioning force (F2). A further means generating a pretensioning force (F1) is situated within the slider (S1), which is especially also a spring. Said spring presses with its left end on a face end of the locking element (A1). The force (F1) is lower than the force (F2).

(19) The elastic jaws (B) are prevented from carrying out a movement directed against each other by clamping on the locking element (A1), at least for such a time until the locking element (A1) is tightly connected to the circuit board (L). When a limit temperature is reached, this connection, which is especially a solder connection, is released and the locking element is moved and lifted by means of the force (F1) from its original position in the direction of the wedge-shaped fin (S). As a result, the jaws (B) can now be moved to such a position that the latched connection (H1; H2) is removed and the greater force (F2) on the slider (S1) allows a rapid movement of said slider.

LIST OF REFERENCE NUMERALS

(20) S1Slider A1Locking element H1; H2Latched connection F1First force F2Second force ADisplay surface RConductor track; connecting surface GHousing BJaws SFin Z1First state Z2Second state VVaristor