Overvoltage protection device with improved integrated overtemperature protection

Abstract

Disclosed is an overvoltage protection device (1a to 1f) with integrated over-temperature protection. The overvoltage protection device comprises: a housing (2); a varistor (3) arranged in the housing (2); a thermal contact circuit breaker (4, 4a to 4f) arranged in the housing (2) and electrically connected in series with the varistor (3); and two terminals (5, 6) protruding through the housing (2), the two terminals being electrically connected to the series connection of the varistor (3) and the heat-sensitive contact circuit breaker (4, 4a to 4f). The heat-sensitive contact circuit breaker (4, 4a to 4f) is designed as a bimetal contact circuit breaker.

Description

Technical Field

[0001] The present invention relates to an overvoltage protection device with integrated overtemperature protection, wherein the overvoltage protection device comprises: a housing; a varistor arranged in the housing; a thermal contact circuit breaker arranged in the housing and electrically connected to the varistor in series; and two terminals extending through the housing, the two terminals being electrically connected to the series connection of the varistor and the thermal contact circuit breaker. Background Art

[0002] Devices of the above type are generally known in the prior art. Unfortunately, varistors deteriorate due to aging and due to the accumulation of overvoltage protection events over time and the leakage current of the varistors, and therefore, the power loss increases accordingly. Overheating of the varistor caused by the leakage current flowing for a specific duration may occur, which is dangerous not only for the varistor itself, but also for other devices nearby that may catch fire. Therefore, the current flow is interrupted by a thermal contact breaker, which protects the device varistor from overheating and thus also avoids danger to other devices near the varistor. In the prior art, the thermal contact breaker includes two contacts welded to each other. One of the two contacts is spring-loaded by a coil spring and is forced away from the other contact. Once the heat generated by the varistor liquefies the solder joint, the spring pulls the contact pair apart and cuts off the current. A disadvantage of such a technical solution is that the temperature when the thermal contact breaker is disconnected is not very well defined, or requires considerable design work to define the temperature. In addition, due to the need for a spring, the known mechanism is relatively complex. Summary of the invention

[0003] Therefore, the object of the present invention is to provide an improved overvoltage protection device with integrated overtemperature protection. In particular, a simple technical solution should be provided which switches off the current at a defined temperature without causing too much design effort.

[0004] The object of the invention is achieved by an overvoltage protection device with integrated overtemperature protection, wherein the thermal contact breaker is embodied as a bimetallic contact breaker.

[0005] Specifically, the bimetallic contact circuit breaker may include a fixed contact, a bimetallic strip having a fixed end and a movable end, and a movable contact formed by or attached to the movable end of the bimetallic strip.

[0006] The type of bimetallic element or bimetallic strip well defines the temperature threshold at which the thermal contact breaker disconnects the current path and thus cuts off the power supply to the varistor. In addition, the bimetallic strip generates the disconnection force without other means and in particular without the use of a spring. Thus, the proposed overvoltage protection device with integrated overtemperature protection is less complex than known devices and at the same time provides a more reliable switching point. In addition, the design of the proposed overvoltage and overtemperature protection device is less complex.

[0007] In one embodiment, the bimetallic strip can also trigger additional functions, such as optical, mechanical or electronic remote and local signaling. For example, the bimetallic strip can actuate a switch that connects a signaling LED or a signaling line to a superior control.

[0008] Further advantageous embodiments are disclosed in the claims and the description as well as in the figures.

[0009] Advantageously, the varistor comprises a contact piece which forms a fixed contact of the bimetallic contact breaker, or to which the fixed contact or the fixed end of the bimetallic strip is mounted. By these measures, very good heat conduction from the varistor to the bimetallic strip can be provided and thus a reliable function of the bimetallic contact breaker can be achieved.

[0010] Advantageously, in the original cold state of the overvoltage protection device with integrated overtemperature protection, the fixed contact is soldered to the movable contact. In this way, since the contact pair of the bimetallic contact circuit breaker remains closed for a long time by the non-liquefied solder joint, a fast operation of the bimetallic contact circuit breaker is provided or supported. During the heating of the bimetallic strip, bending stress is generated in the bimetallic strip without actual shape change. Once the temperature of the solder joint reaches a critical point, the solder joint will liquefy and cause the release of the bending stress in the bimetallic strip and a sudden shape change and movement of the movable end of the bimetallic strip. Thus, the bimetallic contact circuit breaker operates very quickly and also very quickly obtains the necessary distance between the fixed contact and the movable contact. The properties of the solder joint, in particular its melting point, affect the temperature threshold when the bimetallic contact circuit breaker is disconnected. Thus, the temperature threshold can be set by selecting a suitable solder material.

[0011] In another advantageous embodiment, the fixed end of the bimetallic strip

[0012] - in the case where the fixed contact is formed by a contact sheet or in the case where the fixed contact is mounted to a contact sheet, is welded to one of the terminals, or

[0013] - are soldered to the contact pads of the varistor.

[0014] In this way, an accidental separation of the bimetallic strip from the terminal can be avoided when the bimetallic strip is heated. Similarly, the fixed end of the bimetallic strip can be welded to the contact piece of the varistor, and the fixed contact can be arranged on the terminal or formed by the terminal. In the case where the fixed end of the bimetallic strip is welded to the contact piece of the varistor, in particular a very good heat conduction from the varistor to the bimetallic strip can be provided, and thus a reliable function of the bimetallic contact circuit breaker can be achieved.

[0015] Advantageously, the overvoltage protection device with integrated overtemperature protection comprises a spark gap which is arranged in the housing and is electrically connected in series with the varistor and the thermal contact breaker or in parallel with the varistor. The varistor is a voltage limiting element, while the spark gap is a voltage switching element. Thus, by means of the proposed measures, multiple functions can be integrated into the overvoltage protection device with integrated overtemperature protection.

[0016] Advantageously,

[0017] - the spark gap comprises a contact piece which forms a fixed contact, or to which a fixed contact of a bimetallic contact circuit breaker or a fixed end of a bimetallic strip is mounted, or

[0018] The parallel connection of the varistor and the spark gap comprises a common contact piece which forms a fixed contact of the bimetallic contact circuit breaker or to which a fixed contact or a fixed end of a bimetallic strip is mounted.

[0019] In particular, in the case of a common contact piece, by means of the proposed measures, a very good heat conduction from the varistor to the bimetallic strip can be provided and thus a reliable function of the bimetallic contact breaker can be achieved.

[0020] In one embodiment, the fixed end of the bimetallic strip can be welded to the contact piece of the spark gap, or to a common contact piece of the varistor and the spark gap in case the varistor is connected in parallel with the spark gap. However, the function of the bimetallic contact circuit breaker is the same as that already disclosed.

[0021] Advantageously, the bimetallic strip can be preloaded, in particular bent, wherein, in the original cold state of the overvoltage protection device with integrated overtemperature protection, the movable end of the bimetallic strip is forced away from the fixed contact. In other words, the bimetallic strip in the cold state has a bent shape, wherein the movable end is away from the fixed contact. In one embodiment, during the manufacture of the overvoltage protection device with integrated overtemperature protection, the movable end of the bimetallic strip is forced to the fixed contact, and the fixed contact is welded to the movable contact. Once the solder solidifies, the bimetallic strip remains in its preloaded position. Alternatively, it is also possible to first weld the fixed contact to the movable contact so that the bimetallic strip is bent, and then weld the fixed end of the bimetallic strip to one of the terminals or to the contact piece of the varistor, depending on the position of the movable contact. In another embodiment, in a first step, the fixed contact is welded to the movable contact, and, depending on the position of the movable contact, the fixed end of the bimetallic strip is welded to one of the terminals or to the contact piece of the varistor. In a subsequent step, when the arrangement comprising the varistor and the bimetallic contact breaker is installed in the housing, the bimetallic strip is bent by parts of the housing. Through all these measures, the rapid disconnection of the bimetallic contact breaker is further supported.

[0022] In a further advantageous embodiment of the overvoltage protection device with integrated overtemperature protection, the overvoltage protection device comprises an optical indicator,

[0023] the optical indicator is movably arranged at an opening or window of the housing,

[0024] - the optical indicator is mechanically coupled to the movable end of the bimetallic strip, and

[0025] When the bimetallic contact breaker opens, the optical indicator is caused by the bimetallic strip to move from a first position indicating an on-state of the bimetallic contact breaker to a second position indicating an off-state of the bimetallic contact breaker.

[0026] In this way, the operating state of the overvoltage protection device with integrated overtemperature protection can be easily checked from the outside. The optical indicator can include symbols or colors on its surface. For example, the optical indicator can be colored green in a first position of the optical indicator in an area visible through an opening or window in the housing, and can be colored red in a second position of the optical indicator in an area visible through the opening or window.

[0027] Advantageously, the overvoltage protection device with integrated overtemperature protection can include a latching element which holds the bimetallic strip in its open position once the bimetallic contact breaker has opened. In this embodiment, the bimetallic strip can move from its closed position to its open position when heated, but cannot move back when it cools down again. The latching element can in particular be made of an elastic material, such as an elastic plastic, or can be spring-loaded.

[0028] In a further advantageous embodiment, the overvoltage protection device with integrated overtemperature protection can comprise a blocking element made of an electrical insulator, which moves between the fixed contact and the movable contact when the bimetallic contact breaker is opened. For example, the blocking element can be spring-loaded and can be forced between the fixed contact and the movable contact. On the one hand, the blocking element increases the creepage distance between the fixed contact and the movable contact, and on the other hand, the blocking element prevents the bimetallic contact breaker from closing again. Thus, the blocking element provides a dual function.

[0029] Advantageously, the blocking element can keep the bimetallic contact breaker disconnected even when the bimetallic strip cools down again after disconnection. In this way, the bimetallic contact breaker remains disconnected safely. Manual intervention can be allowed to move the blocking element to its original position. Then, the blocking element keeps the bimetallic contact breaker disconnected even when the bimetallic strip cools down again after disconnection until manual intervention from the outside. Generally speaking, once the leakage current reaches a certain threshold level, the varistor will no longer operate. However, in special cases, the overvoltage protection device with integrated overtemperature protection can be put into operation again by the proposed measures until a replacement part appears. If manual intervention is not allowed or possible, it can also be said that when the bimetallic contact breaker is disconnected, the blocking element moves "irreversibly" between the fixed contact and the movable contact. It should also be noted that manual intervention that is not intended by design, such as disassembling or destroying the housing of the overvoltage protection device with integrated overtemperature protection, is not regarded as manual intervention in the above sense.

[0030] Advantageously, the barrier element may comprise an optical indicator and form a combined barrier and indicator element,

[0031] - the combined barrier and indicator element is movably arranged at an opening or window of the housing,

[0032] - the combined barrier and indicator element is mechanically coupled to the movable end of the bimetallic strip, and

[0033] -When the bimetallic contact breaker is disconnected, the combined barrier and indicator element is caused by the bimetallic strip to move from a first position indicating the on state of the bimetallic contact breaker to a second position indicating the off state of the bimetallic contact breaker. In this way, the operating state of the overvoltage protection device with integrated overtemperature protection can also be easily checked from the outside. The optical indicator can also include symbols or colors on its surface. For example, the optical indicator can be colored green in the first position of the combined barrier and indicator element in an area visible through an opening or window in the housing, and can be colored red in the second position of the combined barrier and indicator element in an area visible through the opening or window. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention is now described in more detail below with reference to specific embodiments, but the present invention is not limited to the specific embodiments.

[0035] Figure 1 shows an oblique view of a first example of an overvoltage protection device with integrated overtemperature protection in its operating state;

[0036] Figure 2 shows the Figure 1 Overvoltage protection device with integrated overtemperature protection;

[0037] Figure 3 An oblique view of an overvoltage protection device with integrated overtemperature protection with an optical indicator is shown in its operating state;

[0038] Figure 4 shows the Figure 3 Overvoltage protection device with integrated overtemperature protection;

[0039] Figure 5 An oblique view of an overpressure protection device with integrated overtemperature protection with a blocking element is shown in its operating state;

[0040] Figure 6 shows the Figure 5 Overvoltage protection device with integrated overtemperature protection;

[0041] Figure 7 An oblique view of an overpressure protection device with integrated overtemperature protection having a displaceable blocking element is shown in its operating state;

[0042] Figure 8 shows the Figure 7 Overvoltage protection device with integrated overtemperature protection;

[0043] Fig. 9An oblique view showing an overpressure protection device with integrated overtemperature protection with a rotating blocking element in its operating state;

[0044] Fig.10 shows the Fig. 9 Overvoltage protection device with integrated overtemperature protection;

[0045] Fig.11 Shown based on Fig. 9 and Fig.10 Detailed views of implementations of

[0046] Fig.12 A circuit diagram of an embodiment with a spark gap is shown. DETAILED DESCRIPTION

[0047] In general, identical or similar components are indicated by the same / similar names and reference numerals. The features disclosed in the specification apply to components having the same / similar names and reference numerals, respectively. Indications of orientation and relative positions relate to the associated drawings, and indications of orientation and / or relative positions must be revised in different drawings as appropriate.

[0048] Figure 1 and Figure 2 A first example of an overvoltage protection device 1a with integrated overtemperature protection is shown, Figure 1 in its original cold state ready for operation, and Figure 2 In a fault state. The overvoltage protection device 1a with integrated overtemperature protection comprises: a housing 2; a varistor 3 arranged in the housing 2; a thermal contact breaker 4a arranged in the housing 2 and electrically connected in series with the varistor 3; and two terminals 5, 6 extending through the housing 2, the two terminals being electrically connected to the series connection of the varistor 3 and the thermal contact breaker 4a.

[0049] The thermal contact breaker 4a is implemented as a bimetallic contact breaker and comprises a fixed contact 7, a bimetallic strip 8a having a fixed end E1 and a movable end E2, and a movable contact 9 formed by or attached to the movable end E2 of the bimetallic strip 8a.

[0050] The varistor 3 is held in place in the housing 2 by optional holders 10, 11. The varistor 3 comprises two contact pieces, wherein the upper right contact piece simultaneously forms the fixed contact 7 of the thermal contact breaker 4a, and wherein the lower left contact piece 12 is electrically connected to the terminal 6. It should be noted that the upper right contact piece does not necessarily form the fixed contact 7, but the fixed contact 7 can also be implemented as a separate part electrically connected to the upper right contact piece of the varistor 3.

[0051] If the varistor 3 deteriorates due to aging and due to the accumulation of overvoltage protection events, its leakage current increases, and therefore the power loss increases. The leakage current heats the varistor 3, for example, by heat radiation and / or heat conduction, and thereby also heats the bimetallic strip 8a of the thermal contact breaker 4a. As a result, the bimetallic strip 8a bends and lifts the movable contact 9 from the fixed contact 7, that is, the bimetallic strip breaks the contact pair. In turn, the current flow is interrupted and the device 1a is protected from overtemperature.

[0052] In an advantageous embodiment of the overvoltage protection device 1a with integrated overtemperature protection, the fixed contact 7 can be soldered to the movable contact 9 in the original cold state of the overvoltage protection device 1a with integrated overtemperature protection. In this way, since the contact pair of the bimetallic contact breaker remains closed for a long time by the non-liquefied solder joint, a fast operation of the bimetallic contact breaker is provided or supported. Therefore, during the heating of the bimetallic strip 8a, bending stress is generated in the bimetallic strip without actual shape change. Once the temperature of the solder joint reaches a critical point, the solder joint will liquefy and cause the release of the bending stress in the bimetallic strip 8a and a sudden shape change and movement of the movable end E2 of the bimetallic strip. As a result, the bimetallic contact breaker 4a operates very quickly and also very quickly obtains the necessary distance between the fixed contact 7 and the movable contact 9.

[0053] In this context, it is also advantageous if the fixed end E1 of the bimetallic strip 8a is welded to the terminal 5. In this way, an unintentional separation of the bimetallic strip 8a from the terminal 5 can be avoided when the bimetallic strip 8 is heated. Of course, the role can be changed, and the fixed end E1 of the bimetallic strip 8a can be welded to the contact piece of the varistor 3, and the fixed contact 7 can be arranged on the terminal 5 or formed by the terminal. In one embodiment, the movable contact 9 is welded to the fixed contact 7 on the terminal 5, in another embodiment this is not the case.

[0054] In order to provide or support the quick disconnection movement of the bimetallic strip 8a, the bimetallic strip can be preloaded, in particular bent, wherein, in the original cold state of the overvoltage protection device 1a with integrated overtemperature protection, the movable end E2 of the bimetallic strip 8a is forced away from the fixed contact 7. In other words, in the cold state Figure 1The bimetallic strip 8a has a bent shape, wherein the movable end E2 points away from the fixed contact 7. In one embodiment, during the manufacture of the overvoltage protection device 1a with integrated overtemperature protection, the movable end E2 of the bimetallic strip 8a is forced to the fixed contact 7, and the fixed contact 7 is welded to the movable contact 9. Once the solder solidifies, the bimetallic strip 8a remains in its preloaded position. Alternatively, it is also possible to first weld the fixed contact 7 to the movable contact 9 so that the bimetallic strip 8a is bent, and then the fixed end E1 of the bimetallic strip 8a is welded to the terminal 5. In yet another embodiment, in a first step, the fixed contact 7 is welded to the movable contact 9, and the fixed end E1 of the bimetallic strip 8a is welded to the terminal 5. In a subsequent step, when the arrangement including the varistor 3 and the bimetallic contact breaker 4a is loaded into the housing 2, the bimetallic strip 8a is bent by a portion of the housing 8a.

[0055] Figure 3 and Figure 4 A further embodiment of an overvoltage protection device 1b with integrated overtemperature protection is shown. Figure 1 and Figure 2 The overvoltage protection device 1a with integrated overtemperature protection is similar. Figure 3 shows an overvoltage protection device 1b with integrated overtemperature protection in an original cold state ready for operation, and Figure 4 is shown in its faulty state. Figure 1 and Figure 2 Compared to the embodiment of the present invention, the overvoltage protection device 1b with integrated overtemperature protection comprises an opening or window 13 in its housing 2, and also comprises an optical indicator 14a on the overvoltage protection device 1b with integrated overtemperature protection. The optical indicator 14a is movably arranged at the opening or window 13 and is mechanically coupled to the movable end E2 of the bimetallic strip 8b. When the bimetallic contact breaker 4b is disconnected, the optical indicator 14a is caused by the bimetallic strip 8b to move from a first position indicating the conductive state of the bimetallic contact breaker 4b (see Figure 3 ) moves to a second position indicating the off state of the bimetallic contact breaker 4b (see Figure 4 ). The optical indicator 14a may include a symbol or a color on its top surface. For example, the optical indicator may be colored green in the area visible through the opening 13 in the first position of the optical indicator 14a, and may be colored red in the area visible through the opening 13 in the second position of the optical indicator 14a. In this way, the operating state of the overvoltage protection device 1b with integrated overtemperature protection can be easily checked from the outside. It should be noted at this point that the housing 2 of the overvoltage protection device 1a with integrated overtemperature protection may include an opening 13 also for checking the position of the bimetallic strip 8a.

[0056] Figure 5 and Figure 6 Another embodiment of an overvoltage protection device 1c with integrated overtemperature protection is shown. Figure 1 and Figure 2 The overvoltage protection device 1a with integrated overtemperature protection is similar. Figure 5 shows an overvoltage protection device 1c with integrated overtemperature protection in an original cold state ready for operation, and Figure 6 is shown in its faulty state. Figure 1 and Figure 2 Compared to the embodiment of the present invention, the overvoltage protection device 1c with integrated overtemperature protection comprises an opening or window 13 in its housing 2 and also comprises a blocking element 15 on the overvoltage protection device 1c with integrated overtemperature protection, which holds the bimetallic strip 8c in its open position once the bimetallic contact breaker 4c is opened. In this embodiment, the bimetallic strip 8c can be opened from its closed position ( Figure 5 ) moves to the disconnect position ( Figure 6 ), but cannot move back when it cools down again. This is achieved by the special shape of the movable end E2 of the bimetallic strip 8c and the shape of the locking element 15. To further support the intended function, the locking element 15 can be made of an elastic material (such as an elastic plastic) or can be spring-loaded. In the latter case, the locking element 15 in a given embodiment can move vertically, but is pressed downward by a spring. However, it is easy to understand that Figure 5 and Figure 6 The embodiments shown in are not the only possible ones and variations are possible in a given context.

[0057] Figure 7 and Figure 8 Another embodiment of an overvoltage protection device 1d with integrated overtemperature protection is shown. Figure 1 and Figure 2 The overvoltage protection device 1a with integrated overtemperature protection is similar. Figure 7 shows an overvoltage protection device 1d with integrated overtemperature protection in an original cold state ready for operation, and Figure 8 is shown in its faulty state. Figure 1 and Figure 2Compared to the embodiment of the present invention, the overvoltage protection device 1d with integrated overtemperature protection also comprises an opening or window 13 in its housing 2. In addition, the overvoltage protection device 1d with integrated overtemperature protection comprises a blocking element 16a made of an electrical insulator, which moves between the fixed contact 7 and the movable contact 9 when the bimetallic contact breaker 4d is opened. In this embodiment, the blocking element 16a is spring-loaded and is forced between the fixed contact 7 and the movable contact 9 by a spring 17, which is connected to the blocking element 16a via a connecting strip 18. When the bimetallic contact breaker 4d is opened, the blocking element 16a is pulled between the fixed contact 7 and the movable contact 9 and prevents the bimetallic contact breaker 4d from being closed again.

[0058] In the given example, even when the bimetallic strip 8 cools down again after disconnection, the blocking element 16a still keeps the bimetallic contact breaker 4d disconnected. In addition, in this embodiment, no manual intervention to unlock the overvoltage protection device 1d with integrated overtemperature protection is possible. Therefore, when the bimetallic contact breaker 4d is disconnected, the blocking element 16a moves "irreversibly" between the fixed contact 7 and the movable contact 9.

[0059] In general, once the leakage current reaches a certain threshold level, the varistor 3 will no longer operate. However, in special cases, it may be useful to put the overvoltage protection device 4d with integrated overtemperature protection into operation again until a replacement part is available. To this end, manual intervention may be allowed to move the blocking element 16a to its original position. For example, an additional opening may be provided on the right side of the housing 2 so that the blocking element 16a may be moved upwards by external means (e.g., by using a screwdriver).

[0060] It should be noted that the arrangement of the spring 17 and the use of the connecting strip 18 are not mandatory, but the spring 17 can also be mounted directly to the blocking element 16 a and can be installed vertically in the housing 3 .

[0061] exist Figure 7 and Figure 8 In the embodiment of the invention, the blocking element 16a has a dual function. It not only prevents the reclosing of the bimetallic contact breaker 4d, but also indicates the switching state of the bimetallic contact breaker 4d. For example, the blocking element 16a can be colored green on its top surface, so that when the blocking element 16a is removed from the opening 13, the fault state of the overvoltage protection device 1d with integrated overtemperature protection can be easily visible from the outside. The blocking element 16a with optical indication can also be regarded as a combined blocking and indicator element.

[0062] Fig. 9 and Fig.10A further embodiment of an overvoltage protection device 1e with integrated overtemperature protection is shown. Figure 7 and Figure 8 The overvoltage protection device 1d with integrated overtemperature protection is similar. Fig. 9 shows an overvoltage protection device 1e with integrated overtemperature protection in an original cold state ready for operation, and Fig.10 is shown in its faulty state. Figure 7 and Figure 8 Compared to the embodiment of the invention, the blocking element 16b made of an electrical insulator is different in shape and operation. In detail, the blocking element 16b can rotate around the axis 19 and does not necessarily require a spring for its movement. On the contrary, when the bimetallic contact breaker 4e is opened, the movable end E2 causes the blocking element 16b to rotate. In turn, the blocking part of the blocking element 16b moves between the fixed contact 7 and the movable contact 9. Therefore, the bimetallic contact breaker 4e cannot be closed again.

[0063] Fig.11 A detailed view of a preferred embodiment is shown. Here, the bimetallic strip 8f comprises a notch 20 and the blocking element 16c comprises a nose 21. When the bimetallic contact breaker 4e is open, the nose 21 engages with the notch 20 and prevents reverse rotation of the blocking element 16c and thus reclosing of the bimetallic contact breaker 4f. Fig.11 Also shown in detail is an optical indicator 14c located on top of the barrier element 16c. Similar to the other optical indicators disclosed above, the optical indicator 14c may include symbols and / or colors on its top side that indicate the operating state of the overpressure protection device 1f with integrated overtemperature protection through the window 13. Likewise, the barrier element 16c forms a combined barrier and indicator element.

[0064] Fig.12 Finally, a circuit diagram of a further overvoltage protection device with integrated overtemperature protection is shown, which overvoltage protection device further comprises a spark gap 22, which is electrically connected in series with the varistor 3 and the thermal contact breaker 4. The spark gap 22 can be installed Figures 1 to 11 In any of the embodiments shown in . One option is to weld the fixed end E1 of the bimetallic strip 8a to 8f to the contact piece of the spark gap 22. The varistor 3 is a voltage limiting element, while the spark gap 22 is a voltage switching element. Thus, multiple functions can be integrated into the overvoltage protection device 1a to 1f with integrated overtemperature protection. Fig.12In the embodiment, the spark gap 22 is electrically connected in series with the varistor 3. However, it can also be electrically connected in parallel with the varistor 3. In this case, one option is to weld the fixed end E1 of the bimetallic strips 8a to 8f to the common contact piece of the varistor 3 and the spark gap 22.

[0065] It should be noted that Figure 1 and Figure 2 In the same way as in the implementation method, Figures 3 to 11 The fixed contacts 7 of the embodiment shown in can optionally be welded to the movable contacts 9, 9f, although this need not be done.

[0066] Generally speaking, it is advantageous to arrange the thermal contact breaker 4, and in particular the bimetallic strips 8a to 8f thereof, close to the varistor 3 so that the varistor heats the bimetallic strips 8a to 8f by heat radiation and / or heat conduction. Therefore, it is also advantageous that the fixed contact 7 or the fixed end E2 of the bimetallic strips 8a to 8f is arranged on the contact piece 12 of the varistor 3 or that the contact piece of the varistor 3 even forms the fixed contact 7, as Figures 1 to 11 The same is true in the example disclosed in .

[0067] In the case where the varistor 3 is connected in parallel with the spark gap 22, it is also advantageous to mount the fixed contact 7 or the fixed end E1 of the bimetallic strips 8a to 8f to the common contact piece of the parallel connection. It is also advantageous that the common contact piece even forms the fixed contact 7. In both ways, good heat conduction between the varistor 3 and the bimetallic strips 8a to 8f can also be provided. Alternatively, in the case where the varistor 3 is connected in series with the spark gap 22, the fixed contact 7 or the fixed end E1 of the bimetallic strips 8a to 8f can be mounted to the contact piece of the spark gap 22, or the contact piece can also form the fixed contact 7.

[0068] It should also be noted that Figures 1 to 11 The overvoltage protection devices 1a to 1f with integrated overtemperature protection in FIG. 1 are shown with an open housing 2 to allow the function to be understood. However, in reality, the housing 2 of the overcurrent protection devices 1a to 1f with integrated overtemperature protection is usually closed and may even be sealed.

[0069] It should be noted that the present invention is not limited to the embodiments disclosed above, but a combination of different variants is possible. In practice, the overtemperature protection devices 1a to 1f may have more or fewer components than shown in the drawings. In addition, the description may include the subject matter of other independent inventions.

[0070] It should also be noted that the term "comprising" does not exclude other elements, and the use of the article "a" or "an" does not exclude a plurality. Elements described in connection with different embodiments may also be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

[0071] Reference numerals list

[0072] 1a to 1f Overvoltage protection devices with integrated overtemperature protection

[0073] 2 Housing

[0074] 3 Varistor

[0075] 4. 4a to 4f thermal contact circuit breakers / bimetallic contact circuit breakers

[0076] 5, 6 terminals

[0077] 7 Fixed contacts

[0078] 8a to 8f Bimetallic Strips

[0079] 9.9f movable contacts

[0080] 10, 11 Retainer

[0081] 12 Contact piece of varistor

[0082] 13 Openings / Window

[0083] 14a to 14c Optical indicators

[0084] 15 Locking element

[0085] 16a to 16c Barrier element / combined barrier and indicator element

[0086] 17 Spring

[0087] 18 Connecting strips

[0088] 19 Axis

[0089] 20 Notch

[0090] 21 Nose

[0091] 22 Spark gap

[0092] E1 Fixed end of bimetallic strip

[0093] E2 The movable end of the bimetallic strip

Claims

1. Overvoltage protection device with integrated overtemperature protection (1a to 1f), comprising: - a housing (2), - a varistor (3), arranged in the housing (2), - a thermal contact breaker (4, 4a to 4f) which is arranged in the housing (2) and is electrically connected in series with the varistor (3), and - two terminals (5, 6) protruding through the housing (2), the two terminals being electrically connected to the series connection of the varistor (3) and the thermal contact breaker (4, 4a to 4f), It is characterized in that The thermal contact circuit breakers (4, 4a to 4f) are designed as bimetallic contact circuit breakers.

2. The overvoltage protection device (1a to 1f) with integrated overtemperature protection according to claim 1, characterized in that The bimetallic contact circuit breaker (4, 4a to 4f) comprises a fixed contact (7), a bimetallic strip (8a to 8f) having a fixed end (E1) and a movable end (E2), and a movable contact (9, 9f) formed by or attached to the movable end (E2) of the bimetallic strip (8a to 8f).

3. The overvoltage protection device (1a to 1f) with integrated overtemperature protection according to claim 2, characterized in that: The varistor (3) comprises a contact piece (12) which forms the fixed contact (7) or to which the fixed contact (7) or the fixed end (E1) of the bimetallic strip (8a to 8f) is mounted.

4. The overvoltage protection device (1a to 1f) with integrated overtemperature protection according to claim 2 or 3, characterized in that: In the original cold state of the overvoltage protection device (1a to 1f) with integrated overtemperature protection, the fixed contact (7) is welded to the movable contact (9, 9f).

5. The overvoltage protection device (1a to 1f) with integrated overtemperature protection according to claim 3 or 4, characterized in that: The fixed end (E1) of the bimetallic strip (8a to 8f) - in the case where the fixed contact (7) is formed by the contact piece (12) or in the case where the fixed contact (7) is mounted on the contact piece (12), is welded to one of the terminals (5, 6), or - a contact piece (12) soldered to the varistor (3).

6. Overvoltage protection device (1a to 1f) with integrated overtemperature protection according to any one of claims 1 to 5, characterized in that A spark gap (22) is arranged in the housing (2) and is electrically connected to the varistor (3) and the thermal contact breaker (4, 4a to 4f) in series or electrically connected to the varistor (3) in parallel.

7. The overvoltage protection device (1a to 1f) with integrated overtemperature protection according to claim 6, characterized in that: - the spark gap (22) comprises a contact piece, which forms the fixed contact (7), or the fixed end (E1) of the fixed contact (7) or the bimetallic strip (8a to 8f) is mounted to the contact piece, or The parallel connection of the varistor (3) and the spark gap (22) comprises a common contact piece, which forms the fixed contact (7) or to which the fixed end (E1) of the fixed contact (7) or of the bimetallic strip (8a to 8f) is mounted.

8. Overvoltage protection device (1a to 1f) with integrated overtemperature protection according to any one of claims 2 to 7, characterized in that The bimetallic strip (8a to 8f) is preloaded, in particular bent, wherein, in the original cold state of the overvoltage protection device (1a to 1f) with integrated overtemperature protection, the movable end (E2) is forced away from the fixed contact (7).

9. Overvoltage protection device (1a to 1f) with integrated overtemperature protection according to any one of claims 2 to 8, characterized in that Optical indicators (14a to 14c), - the optical indicator is movably arranged at an opening or window (13) of the housing (2), - the optical indicator is mechanically coupled to the movable end (E2) of the bimetallic strip (8a to 8f), and -When the bimetallic contact circuit breaker (4, 4a to 4f) is disconnected, the optical indicator is caused by the bimetallic strip (8a to 8f) to move from a first position indicating the on state of the bimetallic contact circuit breaker (4, 4a to 4f) to a second position indicating the off state of the bimetallic contact circuit breaker (4, 4a to 4f).

10. Overvoltage protection device (1a to 1f) with integrated overtemperature protection according to any one of claims 1 to 9, characterized in that A locking element (15) holds the bimetallic strip (8a to 8f) in its disconnected position as soon as the bimetallic contactor (4, 4a to 4f) is opened.

11. Overvoltage protection device (1a to 1f) with integrated overtemperature protection according to any one of claims 1 to 10, characterized in that A blocking element (16a to 16c) made of an electrical insulator moves between the fixed contact (7) and the movable contact (9, 9f) when the bimetallic contact breaker (4, 4a to 4f) is disconnected.

12. Overvoltage protection device (1a to 1f) with integrated overtemperature protection according to claim 11, characterized in that The blocking element (16a to 16c) keeps the bimetallic contact breaker (4, 4a to 4f) open even when the bimetallic strip (8a to 8f) cools down again after opening.

13. Overvoltage protection device (1a to 1f) with integrated overtemperature protection according to claim 12, characterized in that Even when the bimetallic strip (8a to 8f) cools down again after disconnection, until manual intervention from the outside, the blocking element (16a to 16c) keeps the bimetallic contact circuit breaker (4, 4a to 4f) disconnected.

14. Overvoltage protection device (1a to 1f) with integrated overtemperature protection according to any one of claims 11 to 13, characterized in that The blocking element (16a to 16c) is spring loaded and is forced between the fixed contact (7) and the movable contact (9, 9f).

15. Overvoltage protection device (1a to 1f) with integrated overtemperature protection according to any one of claims 11 to 14, characterized in that The barrier element (16a to 16c) comprises an optical indicator (14a to 14c) and forms a combined barrier and indicator element, - the combined barrier and indicator element is movably arranged at an opening or window (13) of the housing (2), - the combined barrier and indicator element is mechanically coupled to the movable end (E2) of the bimetallic strip (8a to 8f), and -When the bimetallic contact (4, 4a to 4f) circuit breaker is disconnected, the combined blocking and indicator element is caused to move from a first position indicating the on state of the bimetallic contact circuit breaker (4, 4a to 4f) to a second position indicating the off state of the bimetallic contact circuit breaker (4, 4a to 4f) by means of the bimetallic strip (8a to 8f).

Images