Electrical device and security system

Abstract

The invention relates to a fuse system and an electrical device (1) with an assembly method, comprising an electrical element (2) comprising a body (2A) and a terminal (3), wherein an electrical conductor (5) is electrically connected to the terminal (3) by a fusible link, an arc protector (6), at least one conductive spring (7) and a conductive connecting element (8), wherein connecting terminals of the at least one conductive spring (7) and of the conductive connecting element (8) are in electrical contact, wherein the at least one conductive spring (7) is prestressed and is configured to push the arc protector (6) between the terminal (3) and the electrical conductor (5), wherein the pushing of the arc protector (6) electrically separates the connecting terminals of the at least one conductive spring (7) and of the conductive connecting element (8).

Description

[0001] The present invention relates to an electrical device, a security system comprising the device, the method for triggering the security system and an assembly method.

[0002] Standard thermally protected varistors often contain a metal oxide varistor (MOV) material, a thermal shutdown system, and an attached indicator system.

[0003] The varistor is the voltage-dependent component that overheats when there are strong current surges in a main circuit.

[0004] The thermal shutdown system is a mechanically movable and thermally triggered system designed to completely open the main circuit in the event of varistor overheating due to overvoltage events.

[0005] The indicator system is configured to provide an electrical signal for a shutdown condition. It must be isolated from the high-voltage main circuit, which makes the design and construction of a thermal protection varistor very complex and costly according to the prior art, as disclosed, for example, in published documents US 6636403 B2, EP 2511915 A1, US 9496112 B2, US 6430019 B1, US 11482354 B2, and CN 106711983 A.

[0006] A prior art fuse system is also known from DE 11 2010 005 119 B4. This system provides arc protection with a baffle plate. This baffle plate is pushed between an electrode and a contacting metal attachment by preloaded springs as soon as a low-temperature solder joint melts due to an overvoltage.

[0007] DE 10 2020 210 070 A1 also shows a similar structure.

[0008] It is therefore an object of the present invention to provide an improved or simplified device, a securing system and a mounting solution.

[0009] The present invention is defined by the claims. The invention provides an electrical device, which may be a thermally protected varistor comprising at least one electrical element having a body and a terminal.

[0010] The body may comprise or consist of a varistor. The varistor may comprise or consist of a metal oxide varistor (MOV) material such as ZnO.

[0011] The body can have any suitable shape, e.g. a plate shape, a cylindrical shape or a cuboid shape.

[0012] The terminal may be an electrode or another type of metallization on one surface of the body. The terminal comprises an electrically conductive material. The terminal may comprise a metal or a metal alloy. Preferably, a second terminal may be mounted on another surface of the body. The two terminals may be mounted on two opposite surfaces of the body to apply an electrical voltage to the body.

[0013] The electrical device further comprises an electrical conductor electrically connected to the terminal by a fusion joint, e.g., a solder joint. The electrical conductor may be an electrically conductive metal wire, e.g., a copper wire, or something similar, e.g., a leaf spring.

[0014] The electrical device further comprises an arc protector and two conductive springs, wherein at least in a normal operating state the connecting terminals of the two conductive springs are in electrical contact.

[0015] Alternatively, the electrical device as described in the claims may also comprise only one conductive spring that can be preloaded and another conductive connecting element instead of a second spring. The alternative conductive connecting element must be inserted separately.

[0016] All other embodiments can also be configured with a conductive connecting element other than a spring.

[0017] Preferably, at least one of the springs or both springs are in direct mechanical contact with the arc guard. Preferably, the electrical contact between the two springs is enforced by the arc guard, which holds the springs in a predefined position.

[0018] At least one or both springs can be mechanically pressed against the arc guard.

[0019] If only one spring is pressed against the arc protector, the other spring may rest against a structural element of the electrical device's housing.

[0020] The cross-section of the springs can be any shape, e.g., rectangular or round. The outer shape of the spring can be any shape, e.g., U-shaped or S-shaped.

[0021] The electrical device may comprise a housing, which is preferably electrically insulating and encapsulates all other parts of the electrical device. The housing may be or comprise a cast or molded part and may be made of a non-conductive material, such as a plastic. The cast part may be molded around the other elements of the electrical device, preferably at least around the electrical element. The other components besides the electrical element may be covered by an additional cover, which may be another part of the housing.

[0022] According to the invention, at least one of the two conductive springs is preloaded and configured to press the arc shield between the terminal and the electrical conductor when the fusible link breaks and the electrical conductor and the terminal are electrically separated. The arc shield is then pushed into the former position of the fusible link, which breaks due to melting at high temperatures.

[0023] The arc protection device is positioned accordingly and is under pre-tension because the pre-tensioned spring acts on the arc protection device.

[0024] According to the invention, by sliding the arc guard, the connecting terminals of the two conductive springs are electrically separated, preferably by at least one of the springs being relaxed by sliding the arc guard between the terminal and the electrical conductor, while the other spring, for example, remains in a defined position or is relaxed into a different position than the at least one spring.

[0025] The springs required to bias the arc protection device are also suitable, in the described configuration, for creating a closed circuit that is opened when the fusible link is released and melts.

[0026] In particular, according to one embodiment, the two conductive springs may be connecting wires of an indicator circuit, so-called indicator pins, wherein the indicator circuit is configured to indicate electrical contact between the electrical conductor and the terminal, wherein the indicator circuit is configured to be closed when the electrical conductor and the terminal are electrically connected.

[0027] On the other hand, the indicator circuit is opened because the springs lose contact when the fusible link breaks and the electrical conductor and the terminal are electrically separated.

[0028] Due to the disclosed configuration, the springs required to bias the arc protector are also suitable for providing an indicator circuit configured to indicate electrical contact between the electrical conductor and the terminal. The indicator circuit is advantageously separated from a main circuit comprising the electrical element, the terminal, and the electrical conductor. Thus, no additional galvanic isolation is required between the two circuits.

[0029] In addition, the use of springs eliminates the need for any additional structural elements of the electronic device for the display circuit, which would not be the case without the display circuit.

[0030] In other words, the springs serve two functions. First, they provide a mechanical force to trigger the separation of the terminal and the electrical conductor. Second, they provide a signal to the indicator circuit, which is isolated from the main circuit, which has a higher voltage.

[0031] This minimizes the instrumental effort and simplifies the assembly process.

[0032] In other words, the at least one spring serves to force the arc protection device to extend when the fusible link opens due to overheating of the electrical device, in particular the electrical element and its body. At the same time, the contact between the springs opens and can thus be used as an electrical indicator of an overheating event. For this purpose, a signaling device, e.g., an LED, can be arranged in an electrical circuit with the springs.

[0033] This means that the springs have two functions: providing a mechanical force to trigger the thermal break between the terminal and the electrical conductor and providing a signal to the indicator circuit that is separate from the main high-voltage circuit.

[0034] Arc protection protects against arcs and ensures electrical isolation between the terminal and the electrical conductor in the event of overheating events when the fusible link breaks.

[0035] According to one embodiment, after pressing the arc guard, the two conductive springs are configured to be electrically separated from each other by a spatial gap.

[0036] This configuration is advantageous to ensure electrical isolation between the springs and thus generate or terminate an indication signal.

[0037] According to one embodiment, the two conductive springs are preloaded and configured to press the arc protector between the terminals.

[0038] This configuration is advantageous because it allows for maximum preload. Since the two springs are configured to move to different positions when released, a spatial separation is maintained.

[0039] According to one embodiment, the two conductive springs comprise an electrically conductive metal, preferably at least one of copper and a copper alloy, which are highly conductive materials.

[0040] According to one embodiment, the body of the electrical element is a varistor, preferably a metal oxide varistor. The varistor is advantageously protected against overheating events by the described arrangement and mechanism.

[0041] The invention further relates to an electrical security system comprising the electrical device according to one of the previously described embodiments.

[0042] In the electrical fuse system, the fusible link between the electrical conductor and the terminal is designed to break when the electrical element is heated because the fusible link comprises or consists of a low-temperature melting metal, e.g. a soldering material such as solder.

[0043] The arc arrester is configured to be pushed between the electrical conductor and the terminal by at least one of the two conductive springs when the fusible link breaks. This allows the arc arrester to remove any remnants of the fusible link.

[0044] The terminal and the electrical conductor are then electrically separated and further electrical current through the electrical element and further heat generation are prevented.

[0045] At the same time, the two conductive springs are electrically interrupted by the relaxation of at least one spring during the movement of the arc protection device. The interruption of the springs thus provides a signal indicating that the fuse has been triggered.

[0046] The invention further relates to the method for triggering the fuse and the indication of the triggering of the fuse as previously disclosed.

[0047] The invention further relates to the method for triggering the electrical safety system and the indication of the triggering of the electrical safety system by electrical interruption between the two conductive springs.

[0048] A signaling device can indicate the electrical separation between the two conductive springs. The signaling device can be an LED. The device can signal the electrical interruption by switching off.

[0049] The invention further relates to a method for assembling an electrical device, comprising the following steps: - Providing an electrical element comprising a body and a terminal, - Connection of the terminal and an electrical conductor by means of a fusible connecting material, - Application of an arc adjacent to the electrical conductor and two conductive springs, - Pre-tensioning of at least one of the two conductive springs, wherein the arc guard is pressed against the electrical conductor by the at least one conductive spring which is pre-tensioned, and wherein connecting terminals of the two conductive springs are electrically connected.

[0050] According to one embodiment, in the step of attaching the two conductive springs, a double spring element is attached, in which the two springs are formed in a single element, and wherein the double spring element is separated into the two individual conductive springs after attachment, e.g. by cutting into two parts.

[0051] The further configurations can be made according to any of the above-mentioned embodiments.

[0052] The invention is described below by way of example with reference to figures. The invention is not limited by the examples. The details of the examples may be described differently than described below and combined in any suitable manner. Detailed steps or embodiments of the following examples may be combined with steps or embodiments of the electrical device or assembly method described above.

[0053] The figures show: Fig. 1: Perspective view of a first embodiment of an electrical device without an insulating cover. For clarity, the insulating cover is omitted. The figure shows the device in its manufacturing state, before the springs are separated. Fig. Figure 2: Perspective view of the first embodiment of the electrical device without the insulating cover. For clarity, the insulating cover is omitted. The figure shows the device in an operating state after the springs have been separated, but before the fuse has been triggered. Fig. 3: Side view according to the Fig. 2. Fig. Figure 4: Perspective view of the first embodiment of the electrical device without the insulating cover. For clarity, the insulating cover is omitted. The figure shows the device in a state where the fuse is blown. Fig. 5: Side view according to Fig. 4. Fig. 6: First step of a manufacturing method for producing a second embodiment of the electronic device. An electrical element comprising a body and terminals is assembled. Fig. 7: Second step of a manufacturing method for producing a second embodiment of the electronic device. The electrical element is encapsulated. Fig. 8: Third step of a manufacturing process for producing a second embodiment of the electronic device. The arc protection, springs, and electrical conductor are assembled. Fig. 9: Fourth step of a manufacturing method for producing a second embodiment of the electronic device. The electrical conductor is contacted with the terminal by soldering. Fig. 10: Fifth step of a manufacturing process for producing a second embodiment of the electronic device. The housing of the electronic device is closed with a lid. Fig. 11: Fifth step of a manufacturing process for producing a second embodiment of the electronic device. The double spring element is separated into two springs. Fig. 12: Perspective view of the second embodiment of the electrical device without the insulating cover. The insulating cover is omitted for clarity. The figure shows the device in an operating state after the springs have been separated, but before the fuse has been triggered. Fig. 13: Perspective view of the second embodiment of the electrical device without the insulating cover. The insulating cover is omitted for clarity. The figure shows the device in a state where the fuse is blown.

[0054] The Fig. 1 shows in particular a first embodiment of an electrical device 1.

[0055] The electrical device comprises the electrical element 2 with a first terminal 3 and a second terminal 4. The terminals are designed as metal terminals.

[0056] Only the terminals are freely accessible. The other parts of the electrical element 2, in particular the varistor body, are housed in a housing 9 comprising an insulating casting, e.g., made of plastic or polymer.

[0057] The other elements can be covered by an additional cover (not shown) to cover and protect all elements of the electrical device 1. The housing 9 and the cover form the housing of the device 1.

[0058] The first terminal 3 is in electrical contact with an electrical conductor 5. The contact is preferably implemented as a fusion solder joint. At temperatures below the melting temperature of the fusion solder joint, the solder joint is solid, and the first terminal 3 and the conductor 5 are mechanically connected to each other by the solder joint.

[0059] In this example, the electrical conductor 5 is designed as a spring conductor in the form of a leaf spring.

[0060] Adjacent to the elastic part of the spring conductor 5 is an arc guard 6. The arc guard 6 is pressed against the spring conductor 5 by a spring 7. The spring 7 is electrically conductive.

[0061] During production, spring 7 is used as a double spring element, which is then separated into spring 7 and an additional spring 8. This method simplifies the assembly process.

[0062] In alternative embodiments, a different conductive connecting element 8 can be used as a spring instead of the second spring 8. The alternative conductive connecting element 8 must be inserted separately.

[0063] Fig. Figure 2 shows springs 7 and 8 after separation. The springs are designed as leaf springs. After separation, the two springs 7 and 8 can be used as terminals of an electrical circuit to indicate the status of the safety system.

[0064] As in the Fig. 1 or Fig. As can be seen in Figure 2, the springs 7 and 8 are inserted into specially designed retaining hooks of the housing, in particular the housing 9.

[0065] While the spring 8 is preloaded and held by the retaining hooks, the spring 7 is preloaded by the arc guard 6. The spring 7 relaxes when the arc guard 6 moves toward the fusible link.

[0066] In the Fig. In the operating state shown in Figure 2, the two springs 7 and 8 are preloaded and resting against each other. Thus, a closed circuit can be formed by connecting the two springs with external conductors. An electric current can flow from spring 7 to spring 8, generating an electrical signal.

[0067] In case of overheating of the electrical element, in particular the housing of a varistor, the fusible link melts and the arc protector 6 is pressed by the spring 7 between the first terminal 3 and the electrical conductor 5, as shown in Fig. 4 shown.

[0068] This prevents electrical contact between terminal 3 and electrical conductor 5, preventing electrical current, and further heat buildup in the varistor body. The fuse has blown.

[0069] Since the spring 8 is held in the original position by the retaining hooks of the housing, the contact between the two springs 7 and 8 is also interrupted by a spatial distance between the relaxed spring 7, which is shifted towards the arc protection device 6, and the spring 8.

[0070] In this way, an electrical current in the indicator circuit is interrupted, allowing the overheating event to be indicated in the main circuit.

[0071] Fig. 3 shows a side view corresponding to the perspective view of Fig. 2 corresponds.

[0072] In Fig. Figure 3 shows the cover 10. The electrical conductor 5 is visible through a window 11 in the cover (operating state).

[0073] After the fuse has been blown and the arc protector 6 has moved, the arc protector 6 is visible through the window 11, indicating the changed state. A side view of the device in the blown state with the window 11 is also shown in Fig. 5 shown.

[0074] In the Fig. 6 to 13, a second embodiment is described in detail. Fig. 6 to 11 show the manufacturing process and the Fig. 12 and Fig. 13 again show the operating and triggered state of the device, similar to the Fig. 2 and Fig. 4 with respect to the first embodiment.

[0075] Fig. Figure 6 shows a first step of the manufacturing process. An electrical element 2 comprising a body 2A and terminals 3 and 4 is assembled. The terminals 3 and 4 comprise or consist of an electrically conductive metal, such as copper, nickel, silver, gold, etc., or a metal alloy.

[0076] The first terminal is designed so that it can be contacted by an electrical conductor 5.

[0077] The second connection is already provided with a 4A conductor section for external contacting.

[0078] In a second step of the manufacturing process for the electrical device, the electrical element is encapsulated in a polymer or plastic housing (9). The polymer or plastic is electrically insulating.

[0079] The conductor part 4A of the second terminal and a contacting section 3A of the first terminal are exposed for electrical contacting.

[0080] In the outer shape of the housing 9, special retaining hooks 12 are formed to accommodate the other elements such as the springs 7 and 8, the arc protection 6 and the electrical conductor 5.

[0081] In Fig. Figure 8 illustrates a third step in the manufacturing process of the electronic device. The arc protector 6, the springs 7 and 8, and the electrical conductor 5 are assembled with the encased electrical element 2 to produce the electrical device 1.

[0082] The arc guard 6, the springs 7 and 8 and the electrical conductor 5 can be arranged and fastened using the retaining hooks 12.

[0083] The arc guard 6 of the embodiment shown is pivotally mounted on an axis of the housing 9.

[0084] The two springs 7 and 8 are located on the arc protection 6, as shown in Fig. 8 or Fig. 9. At least the spring 7 presses the arc guard 6 into a position in which the arc guard covers the contacting section 3A.

[0085] To operate the device 1, the electrical conductor 5 is contacted with the contacting section 3A of the terminal 3 by solder, which forms a fusible solder joint, as in Fig. 9 shown.

[0086] Here, too, the electrical conductor 5 is designed as a leaf spring. The arc guard 6 is pivoted into a preloaded state, in which the springs 7 and 8 press the arc guard 6 against the electrical conductor 5 and toward the contact section 3A.

[0087] The housing of the electronic device 1 is then closed by a cover 10, which is placed on the housing 9 covering all elements of the device 1. Only the electrical conductor 5 and the conductor part 4A for external electrical contacting of the electrical element in a main electrical circuit (operating circuit) are exposed; likewise, the springs 7 and 8 for external electrical contacting and for connecting, for example, a signaling device to create a separate display circuit.

[0088] In particular, the springs 7 and 8 can be used again as a single spring double spring element, which is then disassembled into two individual springs in a further step, as in Fig. 11 shown.

[0089] Fig. Figure 12 again shows a perspective view of the second embodiment of the electrical device without the insulating cover. The insulating cover is omitted for clarity. The figure shows the device in its operating state after the springs have been separated, but before the fuse has been triggered.

[0090] When the body 2A of the electrical element 2, e.g., a varistor body, and the adjacent terminals 3, 4 overheat, the solder melts, and the solder joint separates. At this stage, the springs 7 and 8 push the arc protector 6 between the electrical conductor 5 and the first terminal 3. The arc protector 6 moves by pivoting.

[0091] After pivoting the arc guard 6, the springs 7 and 8, which were in electrical contact before pivoting, are no longer in electrical contact because the connecting terminals were preloaded differently and the movement of the springs, in particular the connecting terminals, is different when relaxing.

[0092] Fig. 13 shows the device in a state where the fuse has blown. The indicator circuit formed by the springs and external conductors is also open. The interruption of the indicator circuit therefore indicates the interruption of the main circuit. Reference symbol 1 electrical device 2 electrical element 2A Body of the electrical element 3 first connection 3A Contacting section 4 second connection 4A conductor section 5 electrical conductors 6 Arc protection 7 spring 8 conductive connecting element, e.g. a second spring 9 housings 10 lids 11 windows 12 retaining hooks

Claims

[1] Electrical device (1) comprising an electrical element (2) comprising a body (2A) and a terminal (3), an electrical conductor (5) which is electrically connected to the terminal (3) by a melting connection, an arc protector (6), at least one conductive spring (7) and a conductive connecting element (8), wherein connecting terminals of the at least one conductive spring (7) and the conductive connecting element (8) are in electrical contact, wherein the at least one conductive spring (7) is pre-tensioned and arranged to press the arc protector (6) between the terminal (3) and the electrical conductor (5) when the fusible link is released and the electrical conductor (5) and the terminal (3) are electrically separated, wherein by sliding the arc guard (6) the connecting terminals of the at least one conductive spring (7) and the conductive connecting element (8) are electrically separated. [2] Electrical device (1) according to claim 1, wherein the at least one conductive spring (7) and the conductive connecting element (8) are connecting wires (3) of an indicator circuit arranged to indicate electrical contact between the electrical conductor (5) and the terminal (3), the indicator circuit being arranged to be closed when the electrical conductor (5) and the terminal (3) are electrically connected. [3] The electrical device (1) according to claim 1 or 2, wherein after sliding the arc protector (6), the at least one conductive spring (7) and the conductive connecting element (8) are arranged to be electrically separated by a spatial gap. [4] Electrical device (1) according to one of claims 1 to 3, wherein the conductive connecting element (8) is designed as a second conductive spring, and both conductive springs (7, 8) are prestressed and are designed to push the arc protection (6) between the terminal (3). [5] Electrical device (1) according to one of claims 1 to 4, wherein the at least one conductive spring (7) and / or the conductive connecting element (8) comprises at least one of copper and a copper alloy. [6] Electrical device (1) according to one of claims 1 to 5, wherein the body (2A) of the electrical element (2) is a varistor, preferably a metal oxide varistor. [7] An electrical security system comprising the electrical device (1) according to any one of claims 1 to 6. [8] Electrical security system according to claim 7, wherein the melting connection between the electrical conductor (5) and the terminal (3) is arranged so that it breaks when the electrical element (2) heats up, wherein the arc protection (6) is arranged such that it is pushed between the electrical conductor (5) and the terminal (3) by the at least one conductive spring (7) when the fusible link is released, and wherein the at least one conductive spring (7) and the conductive connecting element (8) are electrically separated when the arc protection (6) is pushed between the electrical conductor (5) and the terminal (3). [9] Method for triggering the electrical safety system according to claim 7 or 8, wherein the triggering of the electrical safety system is indicated by an electrical interruption between the at least one conductive spring (7) and the conductive connecting element (8). [10] Method for triggering the electrical safety system according to claim 9, wherein a signaling device signals the electrical separation between the at least one conductive spring (7) and the conductive connecting element (8). [11] Method of assembling an electrical device (1), comprising the following steps: - Providing an electrical element (2) comprising a body (2A) and a terminal (3), - connecting the terminal (3) and an electrical conductor (5) by means of a fusible connecting material, - Attaching an arc guard adjacent to the electrical conductor (5) and at least one conductive spring (7) and one conductive connecting element (8), - Prestressing the at least one conductive spring (7), wherein the arc guard is pressed against the electrical conductor (5) by the at least one conductive spring (7) which is prestressed, and wherein connecting terminals of the at least one conductive spring (7) and the conductive connecting element (8) are electrically connected. [12] The assembly method according to claim 11, wherein the conductive connecting element (8) is formed as a second conductive spring, and wherein in the step of attaching the two conductive springs (7, 8), a double spring element is attached in which the two springs (7, 8) are formed in a single element, and wherein the double spring element is separated into the two individual conductive springs (7, 8) after attachment.

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