EP1826793A1 - Device for protection against overvoltage with thermal disconnector with double contact surface - Google Patents

Abstract

The device has a disconnecting unit (4) ensuring the disconnection of a varistor (3) from an electrical installation. The unit is recalled from a close configuration in which the varistor is connected to the installation to an open configuration in which the varistor is disconnected from the installation. A blocking unit (6) retains the unit (4) in the close configuration and has fusible elements, where the unit (4) has two contact surfaces secant with respect to each other. The elements adhere to the surfaces, respectively, when the unit (4) is in the close configuration. An independent claim is also included for a method of manufacturing an electrical installation protection device.

Description

The present invention relates to the general technical field of protective devices for installations and electrical equipment against electrical surges, particularly transient, especially due to lightning.

The present invention more particularly relates to a protection device of an electrical installation against overvoltages comprising at least one protection component intended to be connected to the electrical installation, and a disconnection means adapted to ensure the electrical disconnection of said component. for protecting the installation, said disconnecting means being capable of being recalled from a closure configuration in which the protection component is connected to the electrical installation to an opening configuration in which the protection component is disconnected of the electrical installation.

The present invention also relates to a method of manufacturing a device for protecting an electrical installation against overvoltages comprising at least one protection component intended to be connected to the electrical installation, as well as a means of disconnection capable of ensuring the electrical disconnection of said protection component of the installation, said disconnection means being capable of being recalled from a closure configuration in which the protection component is connected to the electrical installation to an opening configuration in which the protective component is disconnected from the electrical installation.

It is known to use protective devices capable of protecting electrical or electronic devices against overvoltages that may for example result from lightning phenomena.

These protection devices generally comprise one or more overvoltage protection components, such as, for example, a varistor or a spark gap. When the protection component or components are exposed to voltages higher than a predetermined threshold value, they are able to discharge the fault current to ground while limiting the overvoltage to a value compatible with the carrying capacity of the installation and the equipment connected to it.

In the event of a failure, especially at the end of their life, the protection components are likely to be subject to significant heating up which can cause serious damage to the installation and present risks for the user, for example by triggering a fire. This is the reason why overvoltage protection devices are generally provided with thermal disconnection means. These thermal disconnection means are intended to isolate the protection component of the electrical installation to be protected in the event of overheating of said component in order to suppress the source power source of the heating and thus prevent the appearance or limit the consequences. harmful to a significant rise in temperature.

In order to give the thermal disconnection means their sensitivity to raising the temperature of the protection component, it is known to use a fuse element whose state may be modified by the heat generated by the protective component. . In particular, it is known to use a fusible solder to make the junction between one of the power supply terminals of the protection component and a movable conductive element, such as a slider or a disconnection blade, which is generally subjected to mechanical stress tending to move it away from said supply terminal. Thus, when excessive heating of the protective component causes the solder to melt, the movable conductive member deviates from the power supply terminal of the protection component, thereby isolating the latter from the installation to be protected.

In order to prevent a dangerous heating of the component, the disconnection should occur before the temperature of the latter reaches a critical threshold. For this purpose, the fusible elements are generally made using specific metal alloys whose melting point is relatively low. Usually, the alloys used for this purpose contain lead and often other toxic materials such as cadmium.

In the short term, health regulations provide for the prohibition of the use of certain toxic materials, particularly lead, as a constituent material of electrical and electronic products.

Thus, it appears necessary to give up the lead alloys used until now to achieve the fusible elements of thermal disconnection means in favor of lead-free alloys whose melting temperature is at least as low.

If such alloys are known, such as certain tin-bismuth alloys, the replacement of the identical fusible elements in the existing overvoltage protection devices is impossible, since the known lead-free alloys do not have the same mechanical characteristics. , and in particular not the same resistance to stress as lead alloys.

In particular, this lower mechanical strength exposes the weld joint to a premature rupture that may occur under the effect of electrodynamic forces exerted on the conductive elements of the protection device when it is traversed by a discharge current corresponding to the clipping of an overvoltage as part of its normal operation. In other words, the use of a lead-free fuse solder is likely to reduce the discharge capacity of the protective device, that is to say degrade its performance by reducing the maximum intensity of the fault current that said device can flow several times in succession without suffering damage.

Thus, the replacement of the lead-fuse elements by lead-free fusible elements faces two major difficulties: the first consisting in keeping a melting point sufficiently low to guarantee the safety of operation, that is to say the triggering sufficiently rapid thermal disconnection means, the second being to ensure sufficient mechanical strength of the junction made by the fuse element, particularly not to disturb the normal operation of the device by an unexpected disconnection when the flow of a discharge current.

The objects assigned to the invention therefore seek to remedy the various disadvantages listed above and to propose a new device for protecting an electrical installation against overvoltages whose thermal disconnection means have improved mechanical strength.

Another object of the invention is to provide an overvoltage protection device that is particularly respectful of the environment.

Another object of the invention is to propose a new surge protection device whose design is particularly simple, inexpensive and reliable.

Finally, another object of the invention is to provide a method of manufacturing an overvoltage protection device for improving the mechanical strength of the means for disconnecting said device.

The objects assigned to the invention are achieved by means of a protection device of an electrical installation against overvoltages comprising at least one protection component intended to be connected to the electrical installation, as well as a means of disconnection adapted to ensure the electrical disconnection of said protection component of the installation, said disconnection means being capable of being recalled from a closure configuration in which the protection component is connected to the electrical installation to a configuration of opening in which the protective component is disconnected from the electrical installation, characterized in that said device comprises at least a first fuse element and a second fuse element able to retain the disconnection means in the closed configuration, and in that the means for disconnecting comprises at least a first contact surface and a second sensitive contact surface which respectively adhere to each other and to which the first and the second fuse element respectively adhere when said disconnection means is in the closed configuration, so as to distribute the stresses exerted on said fuse elements and thus to reinforce the holding mechanical means of said disconnection means.

The objects assigned to the invention are also achieved by means of a method of manufacturing a device for protecting an electrical installation against overvoltages comprising at least one protection component intended to be connected to the electrical installation. , as well as a disconnection means adapted to ensure the electrical disconnection of said protection component of the installation, said disconnection means being able to be recalled from a closure configuration in which the protection component is connected to the electrical installation to an opening configuration in which the protective component is disconnected from the electrical installation, characterized in that it comprises a step (a) of developing the disconnection means at the wherein said disconnecting means is provided with at least a first contact surface and a second contact surface substantially intersecting with each other, and an assembly step (b) during which sets up within said device at least a first fuse element and a second fuse element so that they can hold the disconnection means in the closed configuration and that these respectively adhere to said first and second contact surfaces when said disconnection means is in the closed configuration, so as to distribute the stresses exerted on said fusible elements and thus reinforce er the mechanical strength of said disconnection means.

• la figure 1 illustre, selon une vue schématique, un dispositif de protection conforme à l'invention connecté à une installation électrique à protéger.
• La figure 2 illustre, selon une vue en coupe de face, un dispositif de protection conforme à l'invention dans sa configuration de fermeture.
• La figure 3 illustre, selon une vue en coupe de face, le dispositif de la figure 2 dans sa configuration d'ouverture.
• La figure 4 illustre, selon une vue partielle en coupe de dessus selon la ligne M-M, le dispositif de la figure 2.
• La figure 5 illustre, selon une vue partielle en coupe de dessus, le dispositif de la figure 3, le plan de coupe étant le même que celui de la figure 4.
• La figure 6 illustre, selon une vue de détail agrandie, la partie de la figure 4 délimitée par un cercle.
• La figure 7 illustre, selon une vue en coupe en perspective, une variante de réalisation d'un dispositif conforme à l'invention.

Other features and advantages of the invention will appear in more detail on reading the description which follows, and with the aid of the accompanying drawings given purely by way of illustration and non-limiting, among which:

• Figure 1 illustrates, in a schematic view, a protection device according to the invention connected to an electrical installation to be protected.
• Figure 2 illustrates, in a front sectional view, a protection device according to the invention in its closure configuration.
• Figure 3 illustrates, in a front sectional view, the device of Figure 2 in its opening configuration.
• FIG. 4 illustrates, in a partial sectional view from above along line MM, the device of FIG. 2.
• FIG. 5 illustrates, in a partial view in section from above, the device of FIG. 3, the section plane being the same as that of FIG. 4.
• Figure 6 illustrates, in an enlarged detail view, the portion of Figure 4 delimited by a circle.
• Figure 7 illustrates, in a perspective sectional view, an alternative embodiment of a device according to the invention.

The protection device 1 of an electrical installation 2 against overvoltages according to the invention is intended to be connected bypass (or " parallel ") to said electrical installation 2 to protect the latter against overvoltages, as illustrated Figure 1.

The term " electrical installation " refers to any type of device or network powered electrically and likely to experience voltage disturbances, including transient overvoltages due to lightning.

The protective device 1 can therefore advantageously constitute a surge arrester.

The protection device 1 against overvoltages according to the invention is advantageously intended to be disposed between a phase of the installation to protect 2 and the earth. It is also conceivable, without departing from the scope of the invention, that the device 1, instead of being connected bypass between a phase and the earth, is connected between the neutral and the earth, between the phase and the neutral or between two phases to form a differential protection.

The protection device 1 according to the invention comprises at least one protection component 3 intended to be connected to the electrical installation 2 and protect it against overvoltages, especially transient. In the remainder of the description, it is considered that each protection component 3 against overvoltages is formed by a varistor, it being understood that the use of a varistor is only indicated by way of example and does not constitute any a restriction of the invention.

In other words, the protection device 1 comprises one or more overvoltage protection components which, when exposed to voltages higher than a predetermined threshold value, are able to discharge the fault current to earth. while clipping the surge to a value compatible with the holding of the installation.

Preferably, said varistor 3 is in the form of a substantially flat rectangular parallelepiped and provided with two feed terminals 12, 14.

The protection device 1 also comprises a disconnection means 4 capable of ensuring the electrical disconnection of the protection component 3 of the electrical installation 2, in particular in the event of failure of said protection component 3. Preferably, the disconnection means 4 is which can be recalled from a closure configuration in which the protection component 3 is connected to the electrical installation, as illustrated for example in FIG. 2, to an opening configuration in which the protection component 3 is disconnected from the electrical installation, as illustrated for example in Figure 3.

Preferably, at least part of the disconnection means 4 is movable, preferably in rotation, between a closed position in which said disconnection means 4 provides the electrical connection of the varistor 3 to the electrical installation 2, and a opening position in which said disconnecting means 4 separates the varistor 3 from said installation 2. Thus, the closing and opening positions correspond to the closing and opening configurations respectively.

In a particularly preferred manner, the disconnection means 4 is mounted prestressed when it is in its closed position, that is to say that its movable part is mounted in stress in its closed position and subjected to a force of elastic return F which tends to propel it to its open position. This elastic return force may be external, for example provided by the compression of a spring which is in mechanical connection with the disconnecting means 4, or internal, if the disconnection means 4 is itself elastic. Even more preferably, the disconnecting means 4 is formed by an electrically conductive spring blade 5, for example metal, of which a free end is pre-stressed, for example in flexion, when it is in the closed position. In what follows, we will assimilate for simplicity the disconnection means 4 to a spring blade 5, also called " disconnection blade " without this being a limitation of the invention.

According to a preferred embodiment, the device 1 also comprises a locking means 6 adapted to hold the disconnection blade 5 in its closed position and, under certain conditions, to release the latter to enable it to pass into the open position .

According to the invention, the locking means 6 comprise at least a first fuse element 7 and a second fuse element 8, each of which exerts an elementary retaining force, the combination of which makes it possible to obtain a resultant holding force sufficient to maintain the average disconnection 4 in the closed configuration.

Said first and second fusible elements 7, 8 are in particular sensitive to the heat that can be released from the protective component 3. In In particular, said fusible elements 7, 8 are arranged in such a way that their rupture takes place under the effect of the heat generated by the protection component 3 and result in the release of the spring blade 5. The disconnection means 4 can therefore advantageously constitute a means of thermal disconnection.

By " rupture " is meant any loss of cohesion of the fusible element, which may consist for example of a decrease in its adhesion, in a ductile tearing, in particular due to a softening under stress, in a brittle fracture under the effect shock or partial or total fusion.

More particularly, to ensure their retaining function, said first and second fusible elements 7, 8 will preferably perform, when the disconnection means 4 is in the closed configuration, a mechanical junction type embedding between a fixed element relative to the protection component 3 and the disconnection blade 5.

Thus, the protection device according to the invention comprises at least a first fuse element 7 and a second fuse element 8 able to hold the disconnection means 4 in the closed configuration.

Advantageously, the closure configuration therefore corresponds to a preferentially unstable state of the protection device 1, in which the protection component 3 is electrically connected to the electrical installation 2, and therefore capable of being powered and traversed by an electric current. , in particular a discharge current. The opening configuration corresponds to a state of the device 1 preferably stable in which the disconnection means 4 is in a return position in which it ensures the electrical separation between the protection component 3 and the installation 2, that is to say the isolation of said protection component.

According to an alternative embodiment, the opening configuration may correspond to an isolation state of the protection component 3 as to an isolation state of the device 1 with respect to the electrical installation 2. In particular, the configuration of opening will preferably avoid short-circuiting the electrical installation 2.

Although it is conceivable, without departing from the scope of the invention, that one and / or the other fusible elements are engaged with an auxiliary mechanism indirectly blocking the disconnection blade 5 when it is in in the closed position, said first and second fusible elements will preferably be in direct contact with the disconnecting means 4.

To this end, according to an important feature of the invention, the disconnecting means 4 preferably comprises at least a first contact surface 4A and a second contact surface 4B substantially intersecting with respect to each other and to which adhere respectively the first fuse element 7 and the second fuse element 8 when said disconnection means 4 is in the closed configuration.

Thus, it is possible to distribute the stresses exerted by the disconnection means 4 on said first and second fuse elements 7, 8 and to reinforce the mechanical strength of said disconnection means 4, in particular with respect to the electrodynamic forces which appear during the normal flow of lightning currents through the device 1.

According to a preferred embodiment, said contact surfaces 4A and AB will be substantially perpendicular.

Preferably, said first fuse element 7 and / or said second fuse element 8 comprise a solder. Even more preferably, the first and the second fuse element are each formed by a solder.

It is appropriate to use for making said solders filler materials whose melting temperature is less than or equal to the critical temperature considered as the dangerous threshold in case of heating of the varistor 3.

According to a preferred embodiment, the fuse elements 7, 8 will be made using a tin-bismuth alloy, in particular an alloy containing 43% tin and 57% bismuth. As an indication, the melting temperature of such an alloy is of the order of 138 ° C while that of an alloy comprising 50% tin, 18% cadmium and 32% lead is around 145 ° C. .

Preferably, the fuse elements 7, 8 will therefore comprise, as a filler metal used to make said solder or solders, a metal or an alloy containing less than 0.1% by weight of lead, thus considerably limiting the use of harmful substances.

Particularly advantageously, this use of an alloy whose intrinsic mechanical strength is lower than that of some lead alloys of the prior art is made possible by virtue of the particular configuration, according to the present invention, of fusible elements.

By " contact surfaces " is meant surface elements intended to be positively joined to contact with the fusible elements. In particular, when the corresponding fuse element is formed by a solder, the contact surface will correspond to the zone intended to be wetted by the filler metal to ensure the adhesion thereof. Of Preferably, when the disconnecting means 4 is in the closed configuration, the first contact surface 4A will extend substantially orthogonal to the direction corresponding to the thickness of the first fuse element 7. Similarly, the second contact surface 4B then will preferably extend substantially orthogonal to the direction corresponding to the thickness of the second fuse element 8. In other words, the contact surfaces will preferably correspond to the main directions of extension of the fuse elements which are respectively associated with them.

The term " substantially intersecting " refers to the fact that the contact surfaces 4A, 4B, or at least their extensions in space, meet at a line of intersection, which may be straight or arbitrary. Moreover, depending on whether said surfaces are contiguous or separate, for example staggered, said intersection line may be materialized or not.

More particularly, the first contact surface (4A) preferably extends in a first mean extension plane (P ₁ ), when the disconnection means 4 is in the closed configuration.

Similarly, the second contact surface (4B) preferably extends along a second mean extension plane (P ₂ ), when the disconnection means 4 is in the closed configuration.

By " mean plane of extension " is meant the fact that each contact surface extends essentially in two main directions of space and that it is possible to define two secant middle lines, corresponding for example to a straight line of linear regression of the constituent points of the respective profiles of the surface according to each of these two main directions, the mean extension plane being the area generated by these two mean lines.

Moreover, the mean extension planes (P ₁ ) and (P ₂ ) constitute fixed reference planes associated with the closure configuration and to which reference is made to define the geometry and the movements of the constituent elements of the device.

Of course, the first contact surface 4A and / or the second contact surface 4B may have substantially substantially planar, curved, corrugated, irregular or even a smooth or streaked without departing from the scope of the present invention.

Preferably, the first contact surface 4A or the second contact surface 4B is substantially planar, and particularly preferably, the first and the second contact surfaces 4A, 4B are both substantially planar.

According to an important characteristic of the invention, the disconnection means 4 is preferably able, when passing from the closed configuration to the opening configuration, to move substantially parallel to said first mean extension plane P ₁ . In other words, the disconnection blade 5 will tend to slide flat along said first mean extension plane P ₁ as it moves from its closed position to its open position.

Thus, the return force F will preferably tend to urge the first fuse element 7 in shear, especially at the interface of adhesion between said first fuse element and the first contact surface 4A.

According to another important characteristic of the invention, the disconnection means 4 is preferably able, when it passes from the closed configuration to the opening configuration, to deviate substantially frontally from said second mean extension plane ( P ₂ ).

Thus, the return force F will preferably tend to urge the second fuse element 8 in tension, or tear, in particular at the interface of adhesion between said first fuse element and the second contact surface 4B.

Geometrically, this combination of shearing and tearing localized movements and effects can be obtained by orienting the first mean extension plane P ₁ and the second mean extension plane P ₂ so that they form an angle between 70 ° and 110 °. Preferably, as illustrated in FIGS. 2, 4 and 6, said first and second extension planes will be substantially orthogonal.

Moreover, as illustrated in FIGS. 2, 4 and 6, the first mean extension plane P ₁ will preferably be substantially parallel to one of the faces of the varistor 3 while the second average extension plane P ₂ will preferably be substantially normal to the tangent at the start of the path taken by the disconnection blade 5 to move from its closed position to its open position.

Particularly advantageously, the arrangement of the contact surfaces 4A, 4B according to the invention makes it possible to use the three dimensions of the space to increase the useful surface density in a given volume.

By " useful surface " means a surface effectively contributing to the maintenance of the disconnection means 4 when it is in the closed configuration. Thus, the first contact surfaces 4A, 4B constitute, not exclusively, useful surfaces. According to a preferred embodiment, a useful area will correspond to a wetted area by a filler metal, which has an influence on the maximum allowable stress by the junction thus produced by brazing.

In addition, the arrangement of the contact surfaces according to the invention makes it possible to diversify the nature of the stresses to which the fuse elements are subjected, and in particular to combine shearing and tearing so as to make the most of the mechanical strength capabilities of said elements. fuses.

More particularly, it may advantageously seek to favor a respective arrangement of fusible elements and associated contact surfaces in which the mechanical stress of at least one of said fuse elements, which results from the flow of lightning current (or, in to a lesser extent, the restoring force F ), mainly results in the form (pure shear, for example) with respect to which said fuse element is the most resistant, and / or in which the resulting stress can be minimized by over-sizing the area (section) to which the said solicitation applies.

In other words, the above-mentioned construction arrangements make it possible to reinforce the mechanical strength of the blocking means 6 while having a small overall size.

It is particularly remarkable that this reinforcement of the mechanical strength of the locking means 6 is also likely to allow the device 1 to tolerate violent electrodynamic effects, that is to say in particular to resist the flow of currents of particularly high intensities.

According to an alternative embodiment, the disconnection means 4 comprises a first junction element 10 having two branches, the first and second contact surfaces extend respectively on one and the other of the two branches. Preferably, said branches are arranged in L, for example to form an angle.

Preferably, said first junction element 10 is integral with the disconnection blade 5, which may in particular be provided for this purpose with one or more bent tabs, in particular protruding at right angles to the extension plane. principal of said blade 5.

Preferably, the device 1 according to the invention also comprises a second junction element 11 which is fixed relative to the protection component 3 and which has a shape substantially conjugate to the first junction element 10.

Particularly advantageously, said second joining element 11 can be fixed to, or even preferably integral with, one of the power supply terminals 12, 14 of the varistor 3.

According to a preferred embodiment, when the disconnecting means 4 is in the closed configuration, the first and second fusible elements 7, 8 can be sandwiched between the first joining element 10 and the second connecting element 11. As shown in FIG. 2, 4, 6, it is thus possible to make a direct mechanical and electrical connection between the disconnection blade 5 and the first supply terminal 12 of the varistor 3, by an overlap of the contact surfaces 4A, 4B and corresponding useful surfaces of the fixed elements, formed in this case by the outer surfaces 11A, 11B of the branches of the second joining element 11.

Advantageously, the implementation of an arrangement according to the invention is possible in different configurations of presentation of the supply terminals 12, 14 of the varistor 3. However, a varistor 3 will preferably be used, of which at least one supply terminals protrude from one of its main extension faces, as is the case of the first terminal 12 in FIGS. 2 to 5 and FIG. 7, so as to be able to exploit an extended useful area without significantly increasing the size of the device 1.

Of course, the invention is not limited to a configuration in which the first joining element 10 has a concave shape vis-à-vis the fuse elements. In other words, it would be conceivable to reverse the geometries illustrated in FIGS. 4 and 6, that is to say to make a first projecting junction element 10 bearing against the first and second fuse elements themselves. disposed in the hollow of a second joining element 11 reentrant.

According to an alternative embodiment shown in FIG. 7, the first supply terminal 12 may notably form a kind of seat whose seat would support the first fuse element 7, the backrest of which would support the second fuse element 8 and against which would come to rest the disconnection blade 5 when the latter is in the closed position. Advantageously, in the variant embodiment shown in FIG. 7, said first supply terminal 12 is substantially in the center of one of the main extension faces of the varistor 3, so that the disconnection blade 5, when it pivots to move from its closed position to its open position, can have a large deflection without this increasing the size of the device 1, said displacement being particularly likely to be substantially in a space bounded by the contours of said varistor 3.

Although they can be separated, the first fuse element 7 and the second fuse element 8 are, according to a preferred embodiment, contiguous and form a monolithic assembly 7, 8 when the disconnection means 4 is in the closed configuration. In particular, the filler material seal may be substantially continuous and continuously fill the entire gap formed between the first joining element 10 and the second joining element 11. Similarly, it is possible to drown in the filler material of the portions of the connecting elements which extend beyond the useful surfaces, so as to form, for example, a large drop of solder in which is implemented an arrangement according to the invention .

Furthermore, the device 1 according to the invention may advantageously comprise an insulating casing 20 of standardized format, in which the protective component 3 is in particular mounted. Preferably, the device 1 will also comprise two connection pads 21, 22 allowing to realize the electrical connection interface between the outside and the inside of the housing 20.

Finally, it is perfectly conceivable to employ indifferently a means of disconnection 4 movable in translation, such as a slider, or in rotation without departing from the scope of the invention. Similarly, it is conceivable to provide a more complex blocking means 6, not being limited to a direct soldering of the disconnection blade 5 but comprising, for example, abutment means, such as notches, capable of holding the disconnecting means. 4, said locking means 6 being able to deviate from the path of said disconnecting means 4 to release the movement thereof to its open position.

A method of manufacturing an overvoltage protection device according to the invention will now be described.

Said method of manufacturing a protection device 1 of an electrical installation 2 against overvoltages comprising at least one protection component 3 intended to be connected to the electrical installation, as well as a disconnection means 4 capable of providing the electrical disconnection of said protection component of the installation, said disconnection means being capable of being recalled from a closure configuration in which the protection component 3 is connected to the electrical installation to an opening configuration in which the protection component 3 is disconnected from the electrical installation 2, preferably comprises a step (a) for generating the disconnection means 4 during which said disconnecting means is given at least a first contact surface 4A and a second contact surface 4B substantially intersecting relative to each other.

Preferably, the disconnecting means will be realized in the form of a metal disconnection blade. Advantageously, said blade may be cut and then folded, or stamped, so as to have different portions defining said first and second contact surfaces.

In particular, step (a) may comprise a sub-step (a ') during which a first junction element 10 having two branches on which it is made is preferably produced by cutting and folding a metal blade. extend respectively the first and the second contact surface 4A, 4B.

Preferably, said manufacturing method also comprises a step (b) of assembly during which the set up within the device 1 at least a first fuse element 7 and a second fuse element 8 so that they can hold the disconnection means 4 in the closed configuration and that these respectively adhere to said first and second contact surfaces 4A, 4B when said disconnecting means 4 is in the closed configuration.

Preferably, step (b) will comprise a phase (b ₁ ) during which a protection component 3 will be put in place in the housing 20, one of the supply terminals 12, 14 of which will have a second element of junction 11 of form substantially conjugate to the first junction element 10. Preferably, as is illustrated in Figures 2, 4, 6 and 7, for this purpose the first power supply terminal 12 of the varistor 3 is to form an L-shaped angle iron

Preferably, step (b) will comprise a phase (b ₂ ) during which the disconnection blade 5 is fixed within the housing, such that said blade 5 is electrically connected to one of the connection pads 21, 22 of the device, for example to the first connection pad 21 as shown in Figures 2 and 3.

According to a preferred embodiment, the introduction of the fuse elements 7, 8 will consist of brazing with a low melting point filler material to fix the free end of the disconnection blade 5 at the corresponding terminal 12 of the varistor 3.

More specifically, step (b) will preferably comprise a phase (b ₃ ) in which the first joining element 10 of the second joining element 11 is brought together by bending the free end of the disconnection blade 5 until said joining elements overlap partially delimiting a gap, then a phase (b ₄ ) during which said gap is filled with the aid of the melt filler material.

The steps of the manufacturing process described above are not limiting and their numbering does not constitute a restriction as to their order of execution. For example, it is conceivable to coat filler material with one or other of the joining elements 10, 11 before proceeding with the phases b ₁ , b ₂ , b ₃ , and to cause a simple re-fusion filler material when securing the blade 5 to the first supply terminal 12.

Advantageously, the device according to the invention makes it possible to reinforce the mechanical strength of the thermal disconnection means, by oversizing the junction made by the fusible elements, by multiplying the useful surfaces and by extending their areas, which makes it possible to spread out the filler metal over a wider area of overlap and therefore improve the adhesion of the fasteners. In a particularly advantageous manner this oversizing does not significantly increase the overall size of the device, since it optimizes the useful surface density in a given available volume.

Finally, the device according to the invention advantageously makes it possible to moderate and / or distribute the stresses exerted on the fuse elements, so that it is possible to use non-polluting lead-free alloys to make the said fuse elements substantially maintaining the discharge power of the device, that is to say the maximum intensity of the current that can be passed several times in succession by said device without degradation thereof.

Claims (14)

- Protection device (1) of an electrical installation (2) against overvoltages comprising at least one protection component (3) intended to be connected to the electrical installation, and a disconnection means (4) adapted to electrical disconnection of said protection component of the installation, said disconnection means being capable of being recalled from a closure configuration in which the protection component (3) is connected to the electrical installation to a configuration of opening in which the protection component (3) is disconnected from the electrical installation (2), characterized in that said device (1) comprises at least a first fuse element (7) and a second fuse element (8) adapted to retain the disconnection means (4) in the closed configuration, and in that the disconnecting means (4) has at least a first contact surface (4A) and a second contact surface (4B) substantially secant with respect to each other and to which the first and the second fuse element respectively adhere when said disconnection means (4) is in a closed configuration, so as to distribute the stresses exerted on said fuse elements and thereby reinforce the mechanical strength of said disconnecting means. - Device according to claim 1 characterized in that the first contact surface (4A) extends in a first mean extension plane (P ₁ ) and in that the disconnection means (4) is suitable, when passes from the closure configuration to the opening configuration, to move substantially parallel to said first average plane of extension (P ₁ ). - Device according to one of claims 1 or 2 characterized in that the second contact surface (4B) extends along a second mean plane of extension (P ₂ ), when the disconnecting means is in the closed configuration , and in that the disconnecting means (4) is able, when it passes from the closed configuration to the opening configuration, to deviate substantially frontally from said second mean extension plane (P ₂ ). - Device according to one of the preceding claims characterized in that the first contact surface (4A) and / or the second contact surface (4B) is substantially flat. - Device according to claims 2 and 3 characterized in that the first mean extension plane (P ₁ ) and the second mean extension plane (P ₂ ) form an angle of between 70 ° and 110 °, and preferably are substantially orthogonal. - Device according to one of the preceding claims characterized in that the disconnecting means (4) comprises a first connecting element (10) having two branches, said branches preferably being arranged in L, and in that the first and second contact surfaces extend respectively on one and the other of the two branches. - Device according to claim 6 characterized in that it comprises a second connecting element (11) which is fixed relative to the protective component (3) and which has a shape substantially conjugated to the first connecting element (10), and in that when the disconnecting means (4) is in the closed configuration, the first and second fusible elements (7, 8) are sandwiched between the first connecting element (10) and the second connecting element ( 11). - Device according to one of the preceding claims characterized in that the first fuse element (7) and the second fuse element (8) are contiguous and form a monolithic assembly (7, 8) when the disconnecting means (4) is located in closed configuration. - Device according to one of the preceding claims characterized in that the first fuse element (7) and / or the second fuse element (8) comprises a solder. - Device according to claim 9 characterized in that the filler metal used to produce said solder or brazing contains less than 0.1% by weight of lead. -Dispositif according to one of the preceding claims characterized in that the protection component (3) is formed by a varistor. - Device according to one of the preceding claims characterized in that it constitutes a surge arrester -Process of manufacturing a protection device (1) of an electrical installation (2) against overvoltages comprising at least one protection component (3) intended to be connected to the electrical installation, as well as a means of disconnection (4) capable of ensuring the electrical disconnection of said protection component of the installation, said disconnection means being capable of being recalled from a closure configuration in which the protection component (3) is connected to the installation an opening configuration in which the protection component (3) is disconnected from the electrical installation (2), characterized in that it comprises a step (a) for generating the disconnection means (4) at the during which said disconnecting means is given at least a first surface of contact (4A) and a second contact surface (4B) substantially intersecting with respect to each other, and a step (b) of assembly during which the set up within said device (1 ) at least a first fuse element (7) and a second fuse element (8) so that the fuse element (8) can hold the disconnection means (4) in the closed configuration and that these respectively adhere to said first and second surfaces contact (4A, 4B) when said disconnection means (4) is in the closed configuration, so as to distribute the stresses exerted on said fuse elements and thus enhance the mechanical strength of said disconnecting means. - Manufacturing method according to claim 13 characterized in that the step (a) of developing the disconnecting means (4) comprises a substep (a ') during which is carried out, preferably by folding of a metal blade, a first connecting element (10) having two branches on which respectively extend the first and the second contact surface (4A, 4B).

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