Surge protection device and method for manufacturing such a device

Abstract

The invention relates to a method for manufacturing a surge protection device (1) and a protection device thus obtained. The method comprises the following steps: - electrically connecting a first electrode (14) of a first protection element (6) to a first electrode (15) of a second protection element (7) by means of a heat-sensitive disconnect device (5); - providing a pre-assembled arc-cutting device (22) comprising a cassette (33), an insulating blade (34) mounted movably inside the cassette (33), and at least one elastic element (54, 55); - moving the arc-cutting device (22) until it reaches a final mounting position in which the heat-sensitive disconnect device (5) rests against the insulating blade (34) and pushes said insulating blade (34) towards a retracted position. Figure to be published: 2

Description

Title of the invention: Overvoltage protection device and method for manufacturing such a device technical field

[0001] The invention relates to the field of surge protection devices.

[0002] The invention relates in particular to surge protection devices comprising: - on the one hand, a heat-sensitive disconnecting device which, in a connected state, electrically connects at least two electrodes, each belonging to a respective protective element, and is capable of switching, in the event of heating of one of the protective elements, to a disconnected state in which it no longer ensures the electrical connection between the two electrodes, and, - on the other hand, an arc-cutting device which includes an insulating blade which is able to be inserted between the two electrodes when the heat-sensitive disconnecting device is in the disconnected state, which prevents the formation of an electric arc between said electrodes. Technological background

[0003] For the protection of electrical equipment against transient overvoltages, which may have various origins, such as lightning or industrial disturbances, for example, it is known to use overvoltage protection devices.

[0004] Surge protection devices are designed to be placed upstream and in parallel with the equipment to be protected. They use protective elements, such as varistors or gas discharge tubes, which have the characteristic of having a high impedance under normal conditions and becoming conductive when subjected to an overvoltage exceeding a certain threshold, which is higher than the normal operating voltage of the equipment to be protected. The protective elements thus allow the overvoltages to be diverted.

[0005] Document EP3244504 ​​discloses such a surge protection device which also ensures complete disconnection of the protection elements at the end of their service life. This device comprises a varistor, a gas spark gap, a hot-melt solder joint that electrically connects an electrode of the spark gap and an electrode of the varistor, and a return mechanism that exerts a return force tending to move the varistor and the spark gap away from each other so that, when an overvoltage passing through the varistor and the spark gap causes them to heat up beyond a temperature threshold of As the hot-melt solder melts, the aforementioned electrodes are separated from each other. The overvoltage protection device also includes an arc-cutting device comprising an insulating blade rotatably mounted on the housing of the protection device and a torsion spring that forces the insulating blade against the hot-melt solder so that when the latter melts, the insulating blade positions itself between the spark gap and the varistor, thus preventing the formation of an electric arc.

[0006] Such a surge protection device is not entirely satisfactory. In particular, assembling the arc-cutting device onto the housing is delicate. Furthermore, the design of this protection device requires that the arc-cutting device be installed before the soldering operations that join the various components of the protection device together are carried out. Also, the insulating blade of the arc-cutting device puts stress on the hot-melt solder during the soldering operations or, failing that, must be held in position during these operations, which makes them even more difficult to perform. Summary

[0007] Thus, one idea at the base of the invention is to propose a surge protection device equipped with an arc-cutting device that is simple to manufacture.

[0008] According to one embodiment, the invention provides a method for manufacturing a surge protection device comprising the following steps: - provide at least one first protective element and one second protective element, each comprising a first electrode and a second electrode; - electrically connect the first electrode of the first protective element to the first electrode of the second protective element by means of a thermosensitive disconnection device, the thermosensitive disconnection device being capable of switching, when said thermosensitive disconnection device is subjected to a temperature exceeding a threshold, from a connected state to a disconnected state in which the first electrode of the first protective element and the first electrode of the second protective element are disconnected from each other; - provide a pre-assembled arc-cutting device comprising a cassette, an insulating blade mounted movable inside the cassette between a retracted position and a deployed position and at least one elastic element arranged to return said insulating blade relative to the cassette in the direction of the deployed position; - move the arc-cutting device relative to the first and second protective elements and the thermal disconnect device until it reaches a final mounting position in which the thermal disconnect device rests against the insulating blade and pushes said insulating blade towards the retracted position, the insulating blade being, in said final mounting position of the arc cutting device, capable of being moved relative to the cassette towards the deployed position and of being inserted between the first electrodes of the first and second protective elements, when the heat-sensitive disconnecting device switches to the disconnected state.

[0009] Thus, presenting the arc-cutting device in a pre-assembled form facilitates the manufacture of the protective device. In particular, this allows the arc-cutting device to be positioned relative to the first and second protective elements only after the connection operations of the first and second protective elements using the thermally sensitive disconnect device, which simplifies the manufacturing operations of the thermally sensitive disconnect device.

[0010] According to embodiments, such a manufacturing process may include one or more of the following characteristics.

[0011] According to one embodiment, the elastic element is also housed inside the cassette.

[0012] According to one embodiment, the second electrode of the first protective element and the second electrode of the second protective element are each electrically connected to a connection terminal.

[0013] According to one embodiment, the first protective element, the second protective element and the arc-cutting device are mounted in a housing in the final mounting position.

[0014] According to one embodiment, the housing comprises a base and a cover.

[0015] According to one embodiment, the housing is configured to be fixed onto a rail of fastening.

[0016] According to one embodiment, the cassette has slides and when the arc-cutting device moves relative to the first and second protective elements and the heat-sensitive disconnecting device, protruding portions of the first electrode of the first protective element and the first electrode of the second protective element slide in the cassette slides.

[0017] Thus, the slides have, on the one hand, a function of guiding the movement of the arc-cutting device relative to the first and second protective elements, which facilitates the positioning of the arc-cutting device and, on the other hand, allow the cassette of the arc-cutting device to ensure a function of stiffening the links between the first and second protective elements.

[0018] According to one embodiment, the insulating blade is mounted to slide inside the cassette between the retracted position and the deployed position in a direction that is parallel to the slides.

[0019] According to one embodiment, the invention also provides a surge protection device that can be obtained by the aforementioned process and including: - at least one first protective element and one second protective element, each comprising a first electrode and a second electrode, the first electrode of the first protective element and the first electrode of the second protective element being connected by means of a temperature-sensitive disconnection device, the temperature-sensitive disconnection device being capable of switching, when said temperature-sensitive disconnection device is subjected to a temperature exceeding a threshold, from a connected state to a disconnected state in which the first electrode of the first protective element and the first electrode of the second protective element are disconnected from each other; - a pre-assembled arc-cutting device comprising a cassette, an insulating blade mounted movable inside the cassette between a retracted position and a deployed position and at least one elastic element which is arranged to return said insulating blade relative to the cassette towards the deployed position; said arc-cutting device being positioned relative to the first and second protective elements and the heat-sensitive disconnect device so that the insulating blade rests against the heat-sensitive disconnect device and is held by it in the retracted position, said insulating blade being configured to be moved relative to the cassette towards the deployed position and to enter between the first electrodes of the first and second protective elements, when the heat-sensitive disconnect device goes to the disconnected state.

[0020] According to one embodiment, the cassette includes slides in which are housed protruding portions of the first electrode of the first protection element and of the first electrode of the second protection element.

[0021] According to one embodiment, the arc-cutting device includes a stop for preventing the insulating blade from moving in the deployed position. The stop thus prevents the insulating blade from escaping the cassette before the arc-cutting device is assembled with the other components of the protective device.

[0022] According to one embodiment, the stop is formed by a switch intended to be electrically connected to a remote signaling device. Thus, the arc-cutting device also incorporates some of the elements ensuring the remote signaling functionality.

[0023] According to one embodiment, the first protection element and the second protection element are respectively a first and a second varistors extending parallel to each other.

[0024] According to one embodiment, the first varistor and the second varistor comprise a body, the projecting portions projecting beyond the body, on either side of each of said first and second varistors, along two edges opposites of the said first and second varistors.

[0025] According to one embodiment, the protection device further comprises a third protection element having a first electrode and a second electrode, the first electrode of the third protection element being connected to the first electrode of the first protection element and to the first electrode of the second protection element by the thermosensitive disconnection device.

[0026] According to one embodiment, the second electrode of the third protective element is electrically connected to a connection terminal.

[0027] According to one embodiment, the cassette comprises slides in which protruding portions of the first electrode of the third protective element are housed. Thus, the cassette of the arc-cutting device also provides a function of stiffening the connections of the third protective element with the first and second protective elements.

[0028] According to one embodiment, the third protection element is a third varistor extending perpendicularly below the first and second varistors. This ensures, in particular, the compactness of the protection device.

[0029] According to one embodiment, the third varistor comprises a body, the projecting portions projecting beyond the body of the third varistor, along two opposite edges of said third varistor.

[0030] According to another embodiment, the third protective element is a gas burster.

[0031] According to one embodiment, the first protection element and the second protection element are respectively a first varistor and a second varistor extending parallel to each other, the third protection element being a third varistor extending perpendicularly to the first and second varistors or a gas burst.

[0032] According to one embodiment, the heat-sensitive disconnection device comprises: - a lug which, in the connected state, is positioned between a first leg belonging to the first electrode of the first protective element and a second leg belonging to the first electrode of the second protective element, said lug being fixed to the first leg and the second leg by a thermal fuse connection; and - a braided cable having one end connected to the lug and a second end electrically connected to the first electrode of the third protective element.

[0033] According to one embodiment, the hot-melt joint is a hot-melt braze.

[0034] According to one embodiment, the hot melt solder is made in a tin alloy.

[0035] According to one embodiment, the cassette comprises a first side wall and a second side wall which are fixed to each other, arranged respectively on either side of the insulating blade and positioned in a gap provided between the first protective element and the second protective element, the cassette further comprising a first side wing and a second side wing which extend respectively from an end of the first side wall and the second side wall, perpendicular to said first and second side walls, the first side wing being positioned between the first protective element and the third protective element and the second side wing being positioned between the second protective element and the third protective element.

[0036] According to one embodiment, the first side wall and the second side wall each have a slot through which the first leg and the second leg pass respectively, the cassette further having a free space between the first side wall and the second side wall and through which the braided cable passes.

[0037] According to one embodiment, the protection device further comprises a fourth protection element which includes a first electrode and a second electrode, the first electrode of the fourth protection element being electrically connected to the first electrode of the third protection element.

[0038] According to one embodiment, the fourth protection element is a fourth varistor which is arranged parallel to the third varistor.

[0039] According to one embodiment, the second electrode of the third protection element and the second electrode of the fourth protection element are formed as a single piece.

[0040] According to one embodiment, the first electrode of the third varistor and the first electrode of the fourth varistor have folded portions which extend perpendicularly to the planes of the third and fourth varistors, protrude towards each other and are welded to each other in an overlap zone.

[0041] According to one embodiment, the arc cutting device comprises two elastic elements, each formed by a helical spring which is subjected to compression and which has one end bearing against a support surface of the cassette and one end bearing against a support surface of the insulating blade.

[0042] According to one embodiment, the insulating blade has centering pins around which the helical springs are threaded. This prevents the helical springs from becoming misaligned. Brief description of the figures

[0043] The invention will be better understood, and other purposes, details, features and The advantages thereof will become more apparent during the following description of several particular embodiments of the invention, given only by way of illustration and not limitation, with reference to the attached drawings.

[0044] [Fig. 1] The [Fig.1] is a schematic representation of an electrical circuit of a surge protection device.

[0045] [Fig.2] Fig.2 is an exploded view of a device for protection against over voltages having an electrical circuit conforming to that shown in [Fig.1].

[0046] [Fig.3] The [Fig.3] is a partial perspective view of the overvoltage protection device of the [Fig.2].

[0047] [Fig.4] The [Fig.4] is a partial side view of the overvoltage protection device of the [Fig.2].

[0048] [Fig.5] The [Fig.5] is a perspective view of the electrodes and the thermosensitive disconnect device in a connected state in which it electrically connects three of the varistors of the overvoltage protection device of the [Fig.2].

[0049] [Fig.6] The [Fig.6] is a perspective representation of the arc-cutting device of the overvoltage protection device of the [Fig.2], the insulating blade of said arc-cutting device being in the deployed position.

[0050] [Fig.7] The [Fig.7] is a partial perspective representation of the arc-cutting device of the [Fig.6], the insulating blade of said arc-cutting device being in the retracted position.

[0051] [Fig.8] The [Fig.8] is a partial side view of the arc-cutting device and the heat-sensitive disconnecting device, the heat-sensitive disconnecting device being in the connected state and the insulating blade of said arc-cutting device being in the retracted position.

[0052] [Fig.9] The [Fig.9] is a partial side view of the arc-cutting device and the heat-sensitive disconnecting device, the heat-sensitive disconnecting device being in the disconnected state and the insulating blade of said arc-cutting device being in the deployed position.

[0053] [Fig. 10] The [Fig. 10] is a schematic representation of an electrical circuit of an overvoltage protection device according to a second embodiment.

[0054] [Fig. 11] [Fig. 11] is a partial perspective view of a surge protection device having an electrical circuit conforming to that shown in [Fig. 10].

[0055] [Fig. 12] The [Fig. 12] is a schematic representation of an electrical circuit of an overvoltage protection device according to a third embodiment.

[0056] [Fig. 13] The [Fig. 13] is a partial perspective view of a surge protection device having an electrical circuit conforming to that shown in the [Fig. 12],

[0057] [Fig. 14] The [Fig. 14] is a schematic representation of an electrical circuit of an overvoltage protection device according to a fourth embodiment.

[0058] [Fig. 15] The [Fig. 15] is a partial perspective view of a surge protection device having an electrical circuit conforming to that shown in the [Fig.15].

[0059] [Fig. 16] The [Fig. 16] is a schematic representation of an electrical circuit of a surge protection device according to a fifth embodiment.

[0060] [Fig. 17] The [Fig. 17] is a partial perspective view of a surge protection device having an electrical circuit conforming to that shown in the [Fig.16].

[0061] [Fig. 18] The [Fig. 18] is a schematic representation of an electrical circuit of a surge protection device according to a sixth embodiment.

[0062] [Fig. 19] The [Fig. 19] is a partial perspective view of a surge protection device having an electrical circuit conforming to that shown in the [Fig.18]. Description of the implementation methods

[0063] Figure 1 is a schematic illustration of an electrical circuit of a surge protection device 1. The protection device 1 is intended to be installed in an electrical installation in parallel and upstream of the equipment(s) to be protected. In Figure 1, the electrical installation is a continuous installation and therefore comprises a positive line +, a negative line - and an earth line T.

[0064] The overvoltage protection device 1 circuit comprises three branches: a positive branch 2, a negative branch 3, and an earth branch 4, each intended to be connected to one of the three aforementioned lines. The three branches 2, 3, and 4 converge at a central connection point equipped with a thermally sensitive disconnect device 5. Such an electrical circuit thus has a Y-shaped configuration. The positive branch 2 and the negative branch 3 are each equipped with a protective element, namely a varistor 6, 7 in the embodiment shown. The earth branch 4, which is connected to the earth line, is also equipped with at least one protective element. In the embodiment illustrated in [Fig. 1], the earth branch 4 comprises two varistors 8, 9 arranged electrically in parallel with each other.

[0065] When a varistor 6, 7, 8, 9 is subjected to a voltage lower than an activation voltage, it acts as a high-impedance element so that no current flows through it. Conversely, when subjected to a voltage higher than the activation voltage, the varistor 6, 7, 8, 9 acts as a near-zero-impedance element so as to divert the overvoltage. Such a protection device 1 thus makes it possible to eliminate overvoltages between the positive and negative lines and between one of the positive and negative lines and the Earth line.

[0066] The electrical circuit and the protective elements 6, 7, 8, 9 are described above by way of example only, and it is clear that they may vary depending on the intended application. In particular, in other embodiments, one or more of the aforementioned protective elements are other types of protective elements than varistors, for example, gas discharge tubes.

[0067] In relation to figures 2 to 9, a protection device 1 is described below according to an embodiment corresponding to the electrical circuit schematically illustrated in [Fig.1].

[0068] With reference to [Fig. 2], it can be seen that the protective device 1 comprises a housing 10 including a base 11 and a cover 12 defining an internal space in which the components of the protective device 1 are housed. The housing 10 is, for example, made of plastic. The base 11 is configured to be fixed onto a mounting rail, not shown.

[0069] In the embodiment shown, the varistors 6, 7, 8, 9 are substantially in the shape of a flattened rectangular parallelepiped. Each varistor 6, 7, 8, 9 thus has two large rectangular faces that are parallel to each other. The varistors 6, 7 of the positive branch 2 and the negative branch 3 are arranged geometrically, parallel to each other. As shown in [Fig.3], the varistors 6, 7 are each equipped with two electrodes 13, 14, 15, 16 which are respectively in contact against one and the other of the large faces of said varistor 6, 7. The electrode 13 of the varistor 6, that is to say the one which is disposed on the large face opposite to the varistor 7, is electrically connected to a positive connection terminal 20, that is to say the one intended to be electrically connected to the positive line + of the electrical installation.Similarly, electrode 16 of varistor 7, that is, the one located on the large face opposite varistor 6, is electrically connected to a negative connection terminal 21, that is, the one intended to be electrically connected to the negative line of the electrical installation. Varistors 6 and 7 are separated from each other by a first gap in which are housed the heat-sensitive disconnect device 5 and an arc-cutting device 22, which will be described later.

[0070] The two varistors 8, 9 of the Earth branch are arranged parallel to each other and against each other. Furthermore, these two varistors 8, 9 are arranged perpendicular to the planes of the varistors 6, 7 of the positive 2 and negative 3 branches and below them. The two varistors 8, 9 are separated from the varistors 6, 7 by a second gap. Advantageously, since the varistors 8, 9 are positioned against each other, an electrode 17, visible in particular in [Fig. 4], is common to the two varistors 8, 9 and positioned between them. This electrode 17 is electrically connected to an Earth connection terminal 23, that is to say, the one intended to be electrically connected to the grounding line of the electrical installation.

[0071] As shown in particular in [Fig. 4], the electrodes 18, 19, that is to say those which cover the large faces of the opposing varistors 8, 9, are connected to each other. To this end, said electrodes 18, 19 have folded portions 24, 25. The folded portions extend perpendicularly to the large faces of the varistors 18, 19 and protrude towards each other. One of the folded portions 24, 25 overlaps the other, and the folded portions 24, 25 are welded to each other in the overlapping area.

[0072] Returning to [Fig. 2], it can be seen that, in the embodiment shown, each of the positive 20, negative 21, and ground 23 connection terminals has a metal frame 26 intended to receive a stripped end of a cable from the corresponding line. The connection terminals 20, 21, and 23 each have a screw 27 mounted in a threaded bore 28 in the corresponding metal frame 26, which allows the stripped end of the corresponding cable to be clamped against the metal frame 26 to ensure an electrical connection.

[0073] The heat-sensitive disconnect device 5, connecting the positive 2, negative 3, and ground 4 branches, is particularly visible in Figures 3 and 5. In these figures, the heat-sensitive disconnect device 5 is shown in the connected state. The electrodes 14, 15 of the varistors 6, 7 each have a leg 29, 30 that protrudes towards the gap between said varistors 6, 7. The free end of the legs 29, 30 is folded back and oriented parallel to the planes of the varistors 6, 7. A lug 31 is inserted between the legs 29, 30 and is connected to said legs 29, 30 by a hot-melt connection. The lug 31 is fixed and electrically connected, for example by crimping, to the end of a braided cable 32. The braided cable 32 is soldered at its other end to the electrode 19 of the varistor 8. The hot-melt connection is a connection capable of degrading as soon as it is subjected to a temperature greater than or equal to a temperature threshold.This hot-melt joint can be achieved by any means and, for example, by hot-melt soldering. Hot-melt soldering is, for example, made from a tin alloy.

[0074] Thus, in the event of an overvoltage between the positive and negative lines or between one of the positive and negative lines and the ground line, one of the varistors 6, 7 heats up. The heating of the varistors 6, 7 causes an increase in the temperature of the thermal fuse connection. When the thermal fuse connection is raised to a temperature above its melting point, it melts and no longer secures the terminal 31 to the pins 29, 30. The terminal 31 then disengages from the connection position in which it provides an electrical connection between the positive 2, negative 3, and ground 4 branches, so that these branches are no longer electrically connected to each other. The thermally sensitive disconnect device 5 is then in the de- state connected.

[0075] The arc-cutting device 22 comprises a cassette 33 in which an insulating blade 34 is movably mounted between a retracted position, illustrated in [Fig. 8], and a deployed position, illustrated in [Fig. 9]. As will become apparent from the description below, the arc-cutting device 22 is particularly advantageous in that it is manufactured as a pre-assembled sub-assembly, which simplifies the production of the protective device 1.

[0076] As illustrated, for example, in Figures 3 and 6, the cassette 33 comprises two side walls 35, 36 which are fixed to one another and are arranged respectively on either side of the insulating strip 34. The side walls 35, 36 extend parallel to the planes of the varistors 6, 7 and are inserted into the gap between the varistors 6, 7. The cassette 33 also comprises two side wings 37, 38 which extend respectively from a lower end of each of the side walls 35, 36 and perpendicularly to them. Thus, one of the side wings 37 is arranged between the varistor 6 and the varistor 8, while the other side wing 38 is arranged between the varistor 7 and the varistor 8.

[0077] The cassette 33 is configured to attach to the varistors 6, 7 and 8 and thus provide a stiffening function for the connections between the varistors 6, 7 and 8. To this end, the side walls 35, 36 and the side wings 37, 38 are equipped with slides 39, 40, 41, 42, 43, 44 in which the electrodes 14, 15 and 19 are housed. More particularly, as illustrated for example in [Fig. 3], the electrodes 14 and 15 of the varistors 6 and 7 have projecting portions 45, 46, 47, 48 which protrude beyond the body of said varistors 6, 7, along two opposite edges of said varistors 6, 7 and which are housed in the slides. 39, 40, 41, 42 provided in the side walls 35, 36.Similarly, the electrode 19 of the varistor 8 has projecting portions 49, 50 which protrude beyond the body of the varistor 8 along two opposite edges of said varistor 8 and which are respectively housed in the slide 43, 44 provided in one and the other of the two lateral wings 37, 38. .

[0078] The slides 39, 40, 41, 42, 43, 44 extend parallel to each other and in directions which are parallel to the planes of the varistors 6, 7 and to the planes of the varistors 8, 9, which makes it possible to fix the cassette 33 of the arc-cutting device 22 to the varistors 6, 7, 8 after the latter have been fixed to each other.

[0079] Furthermore, the insulating blade 34 is mounted to move in translation within the cassette 33 between its retracted and extended positions. To achieve this, as shown in [Fig. 5], the insulating blade 34 has curved wings 51, 52 which are mounted to slide in guides 52, 53 formed inside the cassette 33, on the inner face of one of the side walls 36. Advantageously, the The insulating blade 34 is mounted to slide in a direction that is parallel to the directions of the slides 39, 40, 41, 42, 43, 44 in which the electrodes 14, 15, 19 are housed. This allows the insulating blade 34 to be moved towards its retracted position when assembling the arc-cutting device 22 with the varistors 6, 7, 8.

[0080] Furthermore, the arc-cutting device 22 includes at least one elastic element, also housed inside the cassette 33, arranged to return the insulating blade 34 to its deployed position. In the embodiment shown, the arc-cutting device 22 comprises two helical springs 54, 55, which are subjected to compression and each have one end bearing against a bearing surface of the cassette 33 and one end bearing against a bearing surface of the insulating blade 34. Advantageously, as illustrated in Figures 7 to 9, the insulating blade 34 includes centering pins 56, 57 around which the helical springs 54, 55 are threaded, preventing them from becoming misaligned. The centering pins 56, 57 are here provided in grooves made in the insulating blade 34.

[0081] The arc-cutting device 22 also includes a stop 58, visible in particular in [Fig. 9], against which the insulating blade 34 makes contact in the deployed position. Such a stop 58 is particularly advantageous in that it prevents the insulating blade 34 from escaping the cassette 33 before the arc-cutting device 22 is assembled with the other components of the protective device 1. Advantageously, the aforementioned stop 58 is formed by a two-state switch 59. The switch 59 includes a movable blade 60 configured to move when the insulating blade 34 moves from its retracted position to its deployed position and to change the state of the switch 59.The switch 59 is intended to be electrically connected to a remote signaling device capable of signaling, for example to a remote monitoring station, that the thermally sensitive disconnect device 5 is in the disconnected state and that, consequently, the protective device 1 must be replaced.

[0082] As illustrated in particular in Figures 3, 8 and 9, the side walls 35, 36 each have a slot 60, 61 through which passes the leg 29, 30 of one of the electrodes 14, 15 while a free space 62 is provided, in the lower part, between the two side walls 35, 36, through which passes the braided cable 32. The slots 60, 61 as well as the aforementioned free space 62 thus allow the heat-sensitive disconnect device 5 and more particularly the lug 31 to come against the insulating blade 34 and to push it towards its retracted position when the arc-cutting device 22 is assembled with the varistors 6, 7, 8, 9.

[0083] When the protective device 1 is in the assembled state and the heat-sensitive disconnecting device is in the connected state, the insulating blade 34 of the cutting device Arc 22 is in contact with the lug 31 and held in the retracted position by the latter. If one of the varistors 6, 7 overheats, causing the heat-sensitive element to melt, the lug 31 disengages from its connection position, where it connects the pins 29, 30 of the varistors 6, 7, thus disengaging the heat-sensitive disconnect device 5. The insulating blade 34 is then free to move to its extended position under the effect of the restoring force exerted by the helical springs 54, 55. As it moves to its extended position, the insulating blade 34 enters between the pins 29, 30, thereby preventing the formation of an electric arc between them.

[0084] The main steps of the assembly process of the protection device 1 described above are now detailed.

[0085] Initially, two sub-assemblies are made. On the one hand, the varistors 6, 7, 8, 9 are electrically connected to each other; and on the other hand, the arc-cutting device 22 is assembled, the insulating blade 34 and the helical springs 54, 55 being mounted inside the cassette 33.

[0086] In particular, when making the subassembly comprising the varistors 6, 7, 8 and 9 and the thermosensitive disconnection device 5, the pins 29, 30 of the varistors 6, 7 are connected to the lug 31 by a hot-melt connection, for example by means of a hot-melt solder.

[0087] In a second step, the arc-cutting device 22 is assembled with the varistors. To do this, the arc-cutting device 22 is positioned relative to the varistors 6, 7, 8, 9 so that the side walls 35, 36 of the cassette 33 are positioned opposite the gap between the varistors 6, 7 and each of the side wings 37, 38 are positioned opposite the gap between one of the varistors 6, 7 and the varistor 8. Subsequently, the arc-cutting device 22 is moved relative to the varistors 6, 7, 8, 9 by a sliding movement in a direction parallel to the planes of the varistors 6, 7 and to the planes of the varistors 8, 9 until it reaches a final mounting position. The protruding portions 45, 46, 47, 48, 49, 50 then slide in the guides 39, 40, 41, 42, 43, 44.During this sliding movement, the heat-sensitive disconnect device 5, and more specifically the lug 31, comes into contact with the insulating blade 34 and pushes it towards its retracted position, thus supplying elastic potential energy to the helical springs 54, 55. Thus, when the arc-cutting device 22 has reached its final mounting position, the insulating blade 34 is in its retracted position and the helical springs 54, 55 have stored potential energy allowing the insulating blade 34 to return to its deployed position, in which it is located between the legs of the varistors 29, 30, as soon as the heat-sensitive disconnect device 5 switches to the disconnected state.

[0088] The arc-cutting device 22 and the varistors 6, 7, 8, 9 thus assembled can then to be mounted inside the housing 10.

[0089] Figures 10 and 11 illustrate a surge protection device according to a second embodiment. This embodiment differs from that described above in relation to Figures 1 to 9 in that the positive branch 2 and the negative branch 3 are each equipped with two protective elements in series, namely a varistor 6, 7 and a gas discharge tube 63, 64. Such an embodiment is advantageous in that it prevents leakage currents between either the positive or negative lines and earth, as well as between the positive and negative lines.

[0090] Figures 12 and 13 illustrate a surge protection device according to a third embodiment. This embodiment differs from that described above in relation to Figures 1 to 9 in that the Earth branch 4 comprises a gas discharge tube 65 instead of the two varistors 8, 9 arranged electrically in parallel with each other. This reduces the size of the protection device and prevents leakage currents between either the positive or negative lines and earth.

[0091] Figures 14 and 15 illustrate a surge protection device according to a fourth embodiment. This embodiment differs from that described above in relation to Figures 1 to 9 in that, on the one hand, the positive branch 2 and the negative branch 3 are each equipped with two varistors 6, 7, 66, 67 in series, and, on the other hand, the Earth branch 4 has a gas spark gap 65 instead of the two varistors 8, 9 arranged electrically in parallel with each other. The two varistors 6, 7, 66, 67 in series on each of the positive 2 and negative 3 branches increase the maximum discharge current that can be evacuated, while the gas spark gap 65 in place of the two varistors 8, 9 in parallel reduces the size and avoids leakage currents between one of the positive or negative lines and earth.

[0092] Figures 16 and 17 illustrate a surge protection device according to a fifth embodiment. This embodiment differs from that described above in relation to Figures 1 to 9 in that, on the one hand, the positive branch 2 and the negative branch 3 are each equipped with a varistor 6, 7 and a gas spark gap 63, 64 in series, and, on the other hand, the Earth branch 4 has a gas spark gap 65 instead of the two varistors 8, 9 arranged electrically in parallel with each other. The varistor 6, 7 and the gas spark gap 63, 64 in series on each of the positive 2 and negative 3 branches prevent leakage currents between one of the positive or negative lines and earth and between the positive line and the negative line while the gas spark gap 65 in place of the two varistors 8, 9 in parallel reduces the size. a sixth embodiment. This embodiment differs from that described above in relation to figures 1 to 9 in that, on the one hand, the positive branch 2 and the negative branch 3 are each equipped with two varistors 6, 7, 66, 67 and a gas spark gap 63, 64 in series, and, on the other hand, the Earth branch 4 has a gas spark gap 65 in place of the two varistors 8, 9 arranged electrically in parallel with each other. The two varistors 6, 7, 66, 67 in series allow the maximum discharge current that can be evacuated to be increased, the gas spark gaps 63, 64 on the positive 2 and negative 3 branches allow leakage currents to be avoided between one of the positive or negative lines and earth and between the positive line and the negative line while the gas spark gap 65 in place of the two varistors 8, 9 in parallel allows the size to be reduced.

[0094] Although the invention has been described in connection with several particular embodiments, it is clearly evident that it is by no means limited to them and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0095] The use of the verb "comprise", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or other steps than those stated in a claim.

[0096] In the claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

Demands

1. A method for manufacturing a surge protection device (1) comprising the following steps: - provide at least one first protective element (6) and one second protective element (7) each comprising a first electrode (14, 15) and a second electrode (13, 16); - electrically connect the first electrode (14) of the first protective element (6) to the first electrode (15) of the second protective element (7) by means of a thermosensitive disconnection device (5), the thermosensitive disconnection device (5) being capable of switching, when said thermosensitive disconnection device (5) is subjected to a temperature exceeding a threshold, from a connected state to a disconnected state in which the first electrode (14) of the first protective element (6) and the first electrode (15) of the second protective element (7) are disconnected from each other; said process being characterized in that it further comprises the following steps: - provide a pre-assembled arc-cutting device (22) comprising a cassette (33), an insulating blade (34) mounted movable inside the cassette (33) between a retracted position and a deployed position and at least one elastic element (54, 55) which is arranged to recall said insulating blade (34) relative to the cassette (33) in the direction of the deployed position, the cassette (33) having slides (39, 40, 41, 42); - move the arc-cutting device (22) relative to the first and second protective elements (6, 7) and the heat-sensitive disconnect device (5) until it reaches a final mounting position in which the heat-sensitive disconnect device (5) rests against the insulating blade (34) and pushes said insulating blade (34) towards the retracted position, the insulating blade (34) being, in said final mounting position of the arc-cutting device, capable of being moved relative to the cassette (33) towards the deployed position and of being inserted between the first electrodes (14, 15) of the first and second protective elements (6, 7), when the heat-sensitive disconnect device (5) transitions to the disconnected state, during said movement of the arc-cutting device (22) relative to the first and second protective elements (6, 7) and the disconnect device. heat-sensitive connection (5), protruding portions (45, 46, 47, 48) of the first electrode (14) of the first protective element (6) and of the first electrode (15) of the second protective element (7) sliding in the rails (39, 40, 41, 42) of the cassette (33); - mount, in a housing (10), the first protective element (6), the second protective element (7) and the arc-cutting device (22) in the final mounting position.

2. A manufacturing method according to claim 2, wherein the insulating blade (34) is mounted to slide inside the cassette (33) between the retracted position and the deployed position in a direction that is parallel to the slides (39, 40, 41, 42).

3. Overvoltage protection device (1) obtainable by the method according to claim 1 or 2 and comprising: - a housing (10); - at least a first protection element (6) and a second protection element (7) housed in the housing (10) and each comprising a first electrode (14, 15) and a second electrode (13, 16), the first electrode (14) of the first protection element (6) and the first electrode (15) of the second protection element (7) being connected by means of a temperature-sensitive disconnection device (5), the temperature-sensitive disconnection device (5) being capable of switching, when said temperature-sensitive disconnection device (5) is subjected to a temperature exceeding a threshold, from a connected state to a disconnected state in which the first electrode (14) of the first protection element (6) and the first electrode (15) of the second protection element (7) are disconnected from each other;said protective device is characterized in that it comprises a pre-assembled arc-cutting device (22), housed in the casing (10) and comprising a cassette (33), an insulating blade (34) mounted movable inside the cassette (33) between a retracted position and a deployed position and at least one elastic element (54, 55) which is arranged to return said insulating blade (34) relative to the cassette (33) in the direction of the deployed position; said arc-cutting device being positioned relative to the first and second protective elements (6, 7) and the heat-sensitive disconnection device (5) so that the insulating blade rests against the heat-sensitive disconnection device (5) and is held by it in the retracted position, said insulating blade being configured to be moved relative to the cassette (33); towards the deployed position and to enter between the first electrodes (14, 15) of the first and second protective elements (6, 7), when the heat-sensitive disconnecting device (5) switches to the disconnected state; the cassette (33) having slides (39, 40, 41, 42) in which are housed protruding portions (45, 46, 47, 48) of the first electrode (14) of the first protective element (6) and of the first electrode (15) of the second protective element (7).

4. Protective device (1) according to claim 3, wherein the arc-cutting device (22) includes a stop (58) intended to stop the movement of the insulating blade (34) in the deployed position.

5. Protective device (1) according to claim 4, wherein the stop (58) is formed by a switch (59) intended to be electrically connected to a remote signaling device.

6. A protective device according to any one of claims 3 to 5, further comprising a third protective element (8) having a first electrode (19) and a second electrode (17), the first electrode (19) of the third protective element (8) being connected to the first electrode (14) of the first protective element (6) and to the first electrode (15) of the second protective element (7) by the heat-sensitive disconnection device (5).

7. A protective device according to claim 6, wherein the first protective element and the second protective element are respectively a first varistor (6) and a second varistor (7) extending parallel to each other and wherein the third protective element is selected from a third varistor (8) extending perpendicularly to the first and second varistors (6, 7) and a gas burster (65).

8. A protective device according to claim 6 or 7, wherein the heat-sensitive disconnecting device (5) comprises: - a lug (31) which, in the connected state, is positioned between a first leg (29) belonging to the first electrode (14) of the first protective element (6) and a second leg (30) belonging to the first electrode (15) of the second protective element (16), said lug (31) being fixed to the first leg (29) and to the second leg (30) by a hot-melt connection; and - a braided cable (32) having a first end connected to the lug (31) and a second end electrically connected to the first electrode (19) of the third protective element (8).

9. Protective device according to claim 8, in which the cassette (33) comprises a first side wall (35) and a second side wall (36) which are fixed to each other, disposed respectively on either side of the insulating blade (34) and positioned in a gap provided between the first protective element (6) and the second protective element (7), the cassette (33) further comprising a first side wing (37) and a second side wing (38) which extend respectively from an end of the first side wall (35) and the second side wall (36), perpendicular to said first and second side walls (35, 36), the first side wing (37) being positioned between the first protective element (6) and the third protective element (8) and the second side wing (38) being positioned between the second protective element (7) and the third protective element (8).

10. Protective device according to claim 9, in which the first side wall (35) and the second side wall (36) each have a slot (60, 61) through which respectively pass the first tab (29) and the second tab (30), the cassette further having a free space (62) between the first side wall (35) and the second side wall (36) and through which passes the braided cable (32).

11. Protective device (1) according to any one of claims 6 to 10, further comprising a fourth protective element (9) which comprises a first electrode (18) and a second electrode (17), the first electrode (18) of the fourth protective element (9) being electrically connected to the first electrode of the third protective element.

Images