EP0691668A1 - Thermic sub-assembly for circuit breaker - Google Patents

Abstract

The subassembly includes a single member (4) cut from a bimetallic plate such that one portion consists entirely of copper (4A) and a second portion (4B) is entirely steel. The copper portion (4A) has two legs one of which (31) is a sliding fit in an adjustable (7) contact box (6). The second copper leg is soldered to the base (9) of a bimetallic strip (3) whose upper end is in turn connected to a moving switch contact (5). The steel portion (4B) of the member (4) acts as an arcing horn for the circuit breaker. <IMAGE>

Description

The present invention relates to the field of circuit breakers.

As is well known, a circuit breaker comprises one or more isolated circuits, each of these circuits extending between an input terminal and an output terminal and comprising a fixed contact-movable contact couple associated with an extinguishing chamber d 'bow. At least one of these circuits includes one or more trip units associated with a circuit breaker mechanism controlling the movements of the mobile contacts of the circuit breaker. These triggers, well known per se, can be either bimetal thermal triggers, or electromagnetic triggers with excitation coil.

The present invention relates to circuit breaker circuits comprising at least one bimetal thermal trip device. It relates more particularly to circuit breakers whose elements are concentrated in a small box.

This is particularly the case for single-pole and neutral circuit breakers for which the phase and neutral circuits are arranged one next to the other in the housing with an insulating partition. In this type of circuit breaker only the phase circuit includes trip devices. In general, it is a bimetal thermal trip device and an electromagnetic trip device with excitation coil. An example of such a unipolar and neutral circuit breaker is given in the European patent published under the number 403358.

An advantageous arrangement of a phase circuit which can be integrated into such a single-pole and neutral circuit breaker is as follows: one of the terminals is connected to the bimetal strip which is itself connected, on the one hand, to a training horn d 'arc, and, on the other hand, to the mobile phase contact; the other terminal is connected to one end of the excitation coil, the other end of which is connected to another arc-forming horn on which the fixed contact is installed. Here are called arcing horns the two metal plates between which forms and then propagates the electric arc opening of said circuit, the corresponding arc extinguishing chamber intervening between these horns.

Thus, the phase circuit of such a circuit breaker breaks down into a first sub-assembly, called an electromagnetic sub-assembly, comprising one of the terminals, the excitation coil and an arcing horn carrying the fixed contact. , and a second sub-assembly, called thermal sub-assembly, comprising the other terminal, the bimetallic strip, the other arc-forming horn and the movable contact. The latter is also integral with the circuit breaker mechanism of the circuit breaker which is located in a part of the housing covering the parts reserved for the phase and neutral circuits.

The thermal subassembly which has just been defined can be integrated not only into the phase circuit of a single-pole and neutral circuit breaker but also into any circuit breaker circuit comprising a bimetal thermal trip device.

The present invention relates more particularly to such a thermal sub-assembly.

In a known thermal sub-assembly, the terminal comprises a cage crossed by a clamping screw and in which there is a rigid connection on which the end of a braid is welded, the other end of this braid being welded on a large faces of the foot of the bimetallic strip. The other large face of the foot of the bimetallic strip is welded to the corresponding arc-forming horn, the latter extending locally parallel to said bimetallic strip. A second braid is welded, on the one hand, to the upper part of the bimetallic strip and, on the other hand, to the corresponding movable contact.

Such a sub-assembly is not rigid, the two braids which it comprises forming joints. This complicates the installation of this sub-assembly in the circuit breaker housing, since it is necessary to maintain both the bimetal-horn assembly, the terminal and, finally, the movable contact. Above all, this thermal sub-assembly has eight elements, the assembly of which requires five welds. Its assembly is therefore relatively complicated.

A thermal sub-assembly similar to the previous one has also been proposed, except that the rigid connection of the terminal is larger and is directly welded to the foot of the bimetallic strip, extending locally parallel to the latter. The base of the bimetallic strip is thus sandwiched between this connection and the arc-forming horn.

With this arrangement, the terminal, the bimetallic strip and the lower arc-forming horn form a rigid assembly which is easy to install in the case of the circuit breaker. In addition, this sub-assembly no longer comprises only seven elements, the assembly of which requires only four welds.

However, in practice, it is very complicated to weld both the arc-forming horn on one of the large faces of the foot of the bimetallic strip, and the rigid connection coming from the terminal on the other large face.

It has also been envisaged to have a piece of cut and folded sheet metal in a circuit breaker so as to serve both as a connection terminal, a bimetallic strip support and an arc-forming horn. This is the case, in particular, in the circuit breakers described by the French patents published under Nos 2 434 474 and 2 580 861.

However, in this case, this part must be made of steel. Indeed, the arcing horns must be made of this metal to ensure formation and guidance of the arc adapted to its extinction in the arc extinguishing chamber.

However, steel is not a suitable material as regards the connection between the terminal and the bimetallic strip. In fact, this material is not a good conductor enough to avoid local heating problems when the current is strong. Thus, we realized that the arrangement of a steel part playing both the role of connection between the bollard and the bimetallic strip and that of an arc-forming horn was not conceivable, in particular for circuit breakers whose the operating current is greater than 16 amps.

In addition, the fact that the part serving as a bimetal support is connected to the terminal gives rise to a risk of imbalance of the bimetallic strip when manipulating the clamping screw with a view to installing an electric wire in the terminal. Indeed, the action of the tightening screw on this wire will be reflected, through this part, towards the bimetallic strip. However, the latter, to properly perform its function, must not be moved from the position in which it has been adjusted.

For these reasons, only thermal sub-assemblies have been industrially developed for which the part connecting the terminal to the bimetallic strip and that serving as an arc-forming horn are separate parts. The problem of simplifying the mounting of the circuit breaker has therefore not been resolved.

The object of the present invention is in particular to solve all of the problems which have just been mentioned.

To this end, the invention provides a thermal sub-assembly adapted to be integrated into a circuit breaker of the type comprising, in a housing, one or more isolated circuits, each of these circuits extending between an input terminal and a terminal. output and comprising a fixed contact-movable contact pair associated with an arc extinguishing chamber, at least one of these circuits comprising one or more trip devices associated with a circuit breaker mechanism controlling all of said movable contacts, said circuit being formed by the association of said thermal sub-assembly, comprising a terminal, a bimetal thermal trip device, an arc-forming horn and a movable contact, and of another sub-assembly, comprising at least one terminal, a arc-forming horn and a fixed contact, the corresponding arc-extinguishing chamber located between the respective arc-forming horns of these two sub-assemblies, said thermal sub-assembly comprising a part m onoblock simultaneously forming an arc-forming horn, electrical connection between the terminal and the bimetallic strip and support for the bimetallic strip, the latter being welded to said one-piece piece, said thermal sub-assembly being characterized in that said one-piece piece is obtained by cutting out '' a bimaterial plate, of which a first material is a good conductor and the second is suitable for the good formation of an electric arc, then folding so that a first part of this part, entirely resulting from said first material, forms electrical connection between the terminal and bimetallic strip, and a second part of this part, entirely from said second material, forms an arc-forming horn.

Advantageously, this plate will be a strip of two-material copper / steel material. Strips of this material are indeed commercially available comprising a copper strip and a steel strip welded side by side by electron bombardment.

There is thus a simplified thermal sub-assembly, since it is no longer composed of only six parts, the assembly of which requires only three welds, said sub-assembly can nevertheless be installed in a circuit breaker, the current of which functioning is important.

According to another aspect of the present invention, a circuit breaker housing adapted to receive a thermal sub-assembly, as defined above, is characterized in that it comprises means for immobilizing the one-piece part of the thermal sub-assembly, at least two of said immobilization means acting on said one-piece piece between the terminal and the cut support portion of the bimetallic strip, at different places along the length of said piece.

These immobilization means make it possible to prevent stresses exerted on the one-piece part of the thermal sub-assembly by the terminal clamping screw from causing a disturbance of the bimetallic strip. It is necessary that there be at least two immobilization means operating at different locations along the length of the one-piece piece between the terminal and the bimetallic strip support. Indeed, if there is only one, the action of the clamping screw on the piece can cause its local deformation by bending around said immobilization means, causing a disruption of the bimetallic strip.

• la figure 1 est une vue en perspective d'un sous-ensemble thermique selon la présente invention ;
• la figure 2 est une vue en élévation d'une partie du sous-ensemble thermique de la figure 1 installé sur une pièce médiane d'un boîtier ;
• la figure 3 est une vue en perspective d'une pièce monobloc du sous-ensemble thermique de la figure 1 ;
• la figure 4 est une vue en plan de la pièce monobloc de la figure 3 avant pliage ;
• la figure 5 est une vue en plan d'une pièce monobloc avant pliage d'un sous-ensemble thermique selon une variante de la présente invention ;
• la figure 6 est une vue en perspective d'une pièce monobloc d'un sous-ensemble thermique selon une variante de la présente invention.

The characteristics and advantages of the invention will become apparent from the description which follows, with reference to the accompanying drawings, among which:

• Figure 1 is a perspective view of a thermal sub-assembly according to the present invention;
• Figure 2 is an elevational view of part of the thermal sub-assembly of Figure 1 installed on a middle part of a housing;
• Figure 3 is a perspective view of a single piece of the thermal sub-assembly of Figure 1;
• Figure 4 is a plan view of the one-piece part of Figure 3 before folding;
• Figure 5 is a plan view of a single piece before folding of a thermal sub-assembly according to a variant of the present invention;
• Figure 6 is a perspective view of a single piece of a thermal sub-assembly according to a variant of the present invention.

A first embodiment of the present invention will now be described with reference to FIGS. 1 to 4. It is, as can be seen in FIG. 1, a thermal sub-assembly 1 comprising a terminal 2, a thermal trip device with bimetallic strip 3, a lower arc-forming horn 4B and a movable contact 5 connected to said bimetallic strip by a braid 8.

This thermal sub-assembly 1 is adapted to be integrated into the phase circuit of a single-pole and neutral circuit breaker.

The various elements of a single-pole and neutral circuit breaker and their operation being well known, they will not be detailed here.

Let us simply recall that such a circuit breaker comprises a phase circuit and a neutral circuit extending one next to the other between respective input and output terminals, and each comprising a fixed contact-movable contact couple. associated with an arc extinguishing chamber, the phase circuit comprising a bimetal thermal trip device and an electromagnetic trip device with excitation coil associated with a circuit breaker mechanism operating above the phase and neutral circuits, said phase mechanism controlling the movable phase and neutral contacts.

• une borne est connectée au pied du bilame, ce bilame s'étendant sensiblement verticalement de manière à ce que son extrémité intervienne au niveau du mécanisme coupe-circuit, ledit bilame étant connecté par ailleurs, d'une part, à une corne inférieure de formation d'arc, et, d'autre part, audit contact mobile ;
• l'autre borne, elle, est connectée à une extrémité de la bobine d'excitation, cette bobine s'étendant au-dessus des circuits de phase et de neutre à proximité du mécanisme coupe-circuit, l'autre extrémité de la bobine étant connectée à une corne supérieure de formation d'arc sur laquelle est installé le contact fixe ; et
• la chambre d'extinction d'arc correspondante intervient entre lesdites cornes inférieure et supérieure de formation d'arc.

It should also be noted that the phase circuit to which the thermal subassembly advantageously adapts according to the present invention is arranged as follows:

• a terminal is connected to the foot of the bimetallic strip, this bimetallic strip extending substantially vertically so that its end intervenes at the level of the circuit breaker mechanism, said bimetallic strip being also connected, on the one hand, to a lower training horn arc, and, on the other hand, said mobile contact;
• the other terminal is connected to one end of the excitation coil, this coil extending over the phase and neutral circuits near the circuit breaker mechanism, the other end of the coil being connected to an upper arc-forming horn on which the fixed contact is installed; and
• the corresponding arc extinguishing chamber intervenes between said lower and upper arcing horns.

Thus, the phase circuit of such a circuit breaker will be formed by the association of the thermal sub-assembly 1 according to the present invention, of another sub-assembly, called the electromagnetic sub-assembly, comprising a terminal, the coil of excitation and the upper arc-forming horn carrying the fixed contact, and the arc extinguishing chamber.

As can be clearly seen in FIG. 1, the thermal sub-assembly 1 comprises a single piece 4, one end of which is engaged with a stirrup 6 forming a movable cage of the terminal 2, and on which the bimetallic strip 3 is welded.

This single piece 4 is shown alone in Figure 3. As seen in this figure, this piece is formed by an elongated plate folded several times, so that it has two parts 4A and 4B.

As shown in FIG. 3, the first part 4A of the one-piece part 4 extends first of all horizontally then substantially vertically downwards, finally, going back upwards by describing a U.

The horizontal portion of this first part 4A of the part 4 forms a first sub-part 31. As can be seen in FIG. 3, two lateral projections 30 are formed on the free end of this subpart 31.

This sub-part 31 of the first part 4A of the part 4 is, as can be seen in FIG. 1, adapted to cooperate with the stirrup 6. More precisely, this sub-part 31 crosses the stirrup 6, its width being adapted to the interior width of said stirrup, so that sub-portion 31 and stirrup 6 can slide vertically relative to one another. The end of a clamping screw 7, acting along the height of the stirrup 6, is adapted to be worn on this subpart 31 in order to fix the relative height of said part and of said stirrup. The projections 30 and an additional lateral projection 12 formed on one side of the sub-part 31 limit the longitudinal movement of the stirrup on said sub-part.

After this first sub-part 31 of the first part 4A, the part 4 is bent downwards, so that said part 4A has a second sub-part 32 extending downwards in a generally vertical direction. The latter is provided with two lateral projections 33. As can be seen in FIG. 3, this second sub-part is slightly folded below the projections 33, so that its lower part is slightly offset longitudinally.

As can be seen in FIG. 4 showing the part 4 before folding, the first part 4A of the part 4, after the second sub-part 32, continues with a third sub-part 34 offset laterally relative to the sub-parts 31 and 32. As can be seen in FIG. 3, this sub-part 34, after the transverse section which connects it to the sub-part 32, extends first downwards along a first vertical branch 34A, then, after a bend , extends upwards along a second vertical branch 34B.

As can be seen in FIG. 4, at the level of this second vertical branch 34B, the part 4 is again bent laterally so as to approach its longitudinal axis AA.

As seen in Figures 3 and 4, the vertical branch 34B of the sub-part 34 ends in a branch transverse 37 centered relative to the longitudinal axis AA, said vertical branch 34B being on one side of this axis. On the other side of the latter, a tab 35 starts from the transverse branch 37. As can be seen in FIG. 4, when the piece 4 is not yet folded, the tab 35 extends substantially parallel to the end of the sub-part 34. As can be seen in FIG. 3, after folding, this tab 35 extends downwards, in a substantially straight line, with a certain inclination, so that its end is close to the lower end of the first vertical branch 34A of the sub-part 34.

As seen in Figure 3, the end 36 of the tab 35 is folded so as to be offset from the rest of said tab. It is on this end 36 of the lug 35 that the bimetal strip can be welded, as seen in FIG. 1.

Of course, the tab 35 is an integral part of the part 4. It is simply a portion of said part which is cut so that only one end of this portion is linked to the rest of said part, as is see it well in Figure 4.

After the transverse branch 37, the part 4 is bent towards the horizontal and has a second part 4B. As can be seen in FIG. 3, after a short horizontal branch 38A, this part 4B extends first downwards with a certain inclination, forming a branch 38B, then horizontally, forming a branch 38C. This part 4B is centered relative to the longitudinal axis AA of the part 4.

The part 4 before folding, as shown in FIG. 4, is obtained by cutting a plate of two-material copper / steel material.

As explained above, strips of this material, comprising a copper strip and a steel strip welded side by side by electron bombardment, are commercially available. Generally, the separation between the two materials corresponds to the median longitudinal axis of the strip in question.

The part 4 is cut transversely in the strip of bi-material material, that is to say that its longitudinal axis AA corresponds to a width of said strip. It is cut so that its first part 4A is entirely of copper and its second part 4B is entirely of steel. In Figure 4, we see the line 40 of separation between the copper strip and the steel strip.

A housing which can advantageously receive the thermal sub-assembly 1, and of which only a middle part 10 is shown here, has, in conventional manner, a generally parallelepiped shape. A front part of this box is reserved for the circuit breaker circuit breaker mechanism, the rest of the box being shared between the neutral circuit and the phase circuit which extend one next to the other, parallel to the large faces. side of the housing, between their respective terminals acting on the small side faces of the housing.

This housing consists of the assembly of two half-shells acting on either side of a longitudinal plane, and of the central part 10 taken between said half-shells. The central part 10 comprises an insulating partition 11 separating the phase and neutral circuits of the circuit breaker. On either side of the housing, between the housings of the phase and neutral terminals, two parts 11A of this partition 11 extend in the median plane of the housing. The remaining part 11B of the partition 11, connecting the two parts 11A, is offset with respect to the latter towards the large lateral face of the housing corresponding to the compartment of the neutral circuit. The phase circuit is therefore installed in the larger of the two compartments delimited on either side of the partition 11.

Advantageously, the phase circuit will be installed on the central part 10 and then covered by the corresponding half-shell. This piece 10 comes from the molding of the reliefs and hollows forming means for positioning and / or fixing the various elements of said phase circuit. The corresponding half-shell has reliefs and hollows complementary to those of part 10, making it possible to complete the fixing of the various elements.

We see in Figure 2, showing a part of the middle piece 10, the way in which the thermal sub-assembly 1 is installed on the middle piece 10. The movable contact 5 and the braid 8 have not been shown in this figure .

The stirrup 6 forming a movable cage of the terminal 2 is installed in a half-housing 14, delimited by the side wall 18 of the part 10, a lower transverse partition 15 and a lateral transverse partition 19. At this half-housing 14 is associated a complementary half-housing (not shown) formed on the corresponding half-shell to form a housing in which the stirrup 6 can slide vertically. The screw 7 is also placed in a half-housing of the part 10 adapted to be associated with a complementary half-housing (not shown) of the corresponding half-shell.

The part 4, of which the sub-part 31 of the part 4A, forming a fixed conductive part of the terminal 2, is located inside the stirrup 6 with the screw 7 which bears on its upper face, is installed on the middle part 10 in the manner which will now be described.

As can be seen in FIG. 2, a lateral portion of the end of this sub-part 31, including one of the lateral projections 30, is introduced into a housing 21 formed in the side wall 18 of the part 10, at the top a notch 16 intended to form, in cooperation with a complementary notch of the corresponding half-shell, an access port to the terminal 2.

On the other hand, the second sub-part 32 of this part 4A is in abutment against the lower part of the transverse partition 19 whose upper part, slightly offset with respect to said lower part, limits as we have seen the caliper housing 6. One of the lateral projections 33 is engaged with a housing 22 formed in the partition 11.

The lateral offset occurring between the second sub-part 32 and the third sub-part 34 of the part 4B of the part 4 corresponds to the offset between the parts 11A and 11B of the partition 11, the part 11A extending in a median plane of the circuit breaker, and the part 11B being offset towards the compartment reserved for the neutral circuit. Thus, this third sub-part 34 remains close to the partition 11, leaving a large free space in which the bimetallic strip can be struggled.

This sub-part 34 passes between two transverse walls 20 and 23 which delimit a passage extending first vertically, then horizontally, as can be seen in FIG. 2. In the vertical part of this passage, two pins 27 and 28 are formed one above the other on the opposite walls respectively 20 and 23, said lugs being adapted to deform elastically when the vertical branch 34A of the sub-part 34 is introduced into said vertical passage, so as to immobilize said branch. The transverse wall 23 is of a height such that it does not touch the tab 35 opposite which it is located, as can be seen in FIG. 2.

Behind the transverse wall 20, and passing through the latter, there is a suitable half-housing 17, with another half-housing (not shown) formed in the corresponding half-shell, to receive a bimetal adjustment screw. As can be seen in Figure 2, this screw will be located opposite the foot of the bimetallic strip and can therefore bear against it.

As can be seen in FIG. 2, the top of the vertical branch 34B of the sub-part 34 is in abutment against a transverse relief 25. The part 4B of said part 4 first passes over this transverse relief 25 and below a relief 26, then follows a transverse wall 24 which extends said relief 25, as seen in FIG. 2.

Thus installed, the part 4 forms bimetallic support, by means of the tab 35 on which the bimetallic strip is welded.

Part 4A of this part provides the electrical connection between, on the one hand, the bimetallic strip and, on the other hand, the terminal of which it forms the fixed conductive part. This part 4A is entirely of copper, a good conductive material.

Finally, part 4B of this part forms a lower arc-forming horn of the circuit circuit of the circuit breaker. This part is entirely made of steel, a material suitable for the formation of an electric arc.

When, once the elements of the phase circuit are installed on the central part 10, the half-shell forming the cover of the compartment reserved for the phase circuit is installed on said central part, the lateral portion of the end of the sub-part 31 of part 4A of part 4 which is outside the housing 21 will be installed in a housing formed on said half-shell (not shown), complementary to said housing 21. The housing thus formed, in which is taken the end of the sub-part 31, forms a first means of immobilizing the part 4.

Similarly, the lateral projection 33 still free from the sub-part 32 will be installed in a housing (not shown) formed in this half-shell. The two projections 33 will thus be trapped in respective housings which together form a second means of immobilizing the one-piece part 4 in the case of the circuit breaker.

To these first and second immobilization means are added the pins 27 and 28 which immobilize the first vertical branch 34A of the third sub-part 34 of the part 4A, forming together a third means of immobilizing the monobloc part 4 in the circuit breaker box.

These three immobilization means cooperate to immobilize the single piece 4 inside the housing.

There is no need to multiply the means for immobilizing the part 4, this running the risk of complicating the installation of the thermal sub-assembly in the housing. At most, we could consider adding a fourth immobilization means operating at the free end of part 4B of part 4.

In any case, it is essential that the part of the thermal sub-assembly which carries the bimetallic strip retains a certain flexibility in order to allow the latter to be adjusted. Here, the support of the bimetallic strip, that is to say the tab 35 which is connected to the rest of the part 4 only by one end, is flexible enough to allow the adjustment of said bimetallic strip.

It should be noted that the second and third immobilization means intervene between terminal 2 and the bimetallic strip support leg 35 in two different places along the length of said part.

These second and third immobilization means make it possible to prevent transmission to the lug 35 of disturbances due to stresses exerted on the part 4 by the screw 7. The arrangement of at least two immobilization means intervening between the terminal and the bimetal support avoids local deformation by bending of the part 4.

It should also be noted that, in the example which has just been described, the tab 35 carrying the bimetallic strip is connected to the rest of the part 4 in a part of the latter very far from the terminal 2 and, therefore, of any disturbances which may arise from the action of the screw 7.

Finally, the numerous bends in part 4 also contribute to attenuating the propagation of these disturbances. In the example shown, the immobilization means intervene on either side of the first downward bend as described in part 4, on the one hand, and on either side of the first lateral bend of this part, on the other hand. This arrangement advantageously contributes to the attenuation of the disturbances propagating on the part 4 between the terminal and the bimetallic strip support.

For market requirements, it is necessary to have two different versions of circuit breaker, one for which the phase circuit is located to the right of the circuit breaker in front view and the other for which this circuit is located at left of the circuit breaker in front view. Depending on whether it is to be integrated into a phase circuit acting on the right or on the left of the circuit breaker, the one-piece part of the thermal sub-assembly must be different.

FIG. 4 shows a part 4 intended to be integrated into a phase circuit acting on the right of the circuit breaker. FIG. 5 shows a part 104 intended to be integrated into a phase circuit acting on the left of the circuit breaker. As can be seen, the parts located in FIGS. 5 and 6, to the right of the transverse axis BB of parts 4 and 104, are identical. As for the parts of these parts located to the left of the axis BB, they are symmetrical with respect to the longitudinal axis AA. Thus, the same tool can be used to carry out the folding operations allowing the production of parts 4 and 104.

Finally, it should be noted that the ends 36 and 136 of the lugs 35 and 135 of the parts 4 and 104 are both centered relative to the longitudinal axis AA of the part 4. This makes it possible to facilitate the automated welding operations of the bimetallic strip, axis AA, which is the median axis of part 4B of part 4, which can be taken as a reference axis.

As is well known, a unipolar and neutral circuit breaker can be converted into the circuit breaker part of a unipolar and neutral differential circuit breaker by a few adjustments to its structure. In particular, the primary neutral and phase windings of the differential part must be connected in series on the corresponding circuits of the circuit breaker part. It has been proposed that the connection of the primary phase winding to the circuit circuit of the circuit breaker is made by two transverse connections, one of which is engaged with a connection connected to the bimetallic strip and the other engaged with a connected connection. at the terminal. Thus, to adapt the thermal sub-assembly described here to the circuit breaker part of a unipolar and neutral differential circuit breaker, it suffices to cut the one-piece part 4 in the manner shown in FIG. 6, that is to say remove the sub-part 31 and a large portion of the sub-part 32 from the part 4A of this part 4. On what remains of the sub-part 32 can be welded the transverse connection from the primary phase winding and to be connected to the bimetallic strip.

Claims (10)

Thermal sub-assembly adapted to be integrated in a circuit breaker of the type comprising, in a housing, one or more isolated circuits, each of these circuits extending between an input terminal and an output terminal and comprising a couple of fixed contact- mobile contact associated with an arc extinguishing chamber, at least one of these circuits comprising one or more trip devices associated with a circuit breaker mechanism controlling all of said mobile contacts, said circuit being formed by the association of said sub -thermal assembly, comprising a terminal, a bimetal thermal trip device, an arc-forming horn and a movable contact, and of another sub-assembly, comprising at least one terminal, an arc-forming horn and a fixed contact, the corresponding arc extinguishing chamber located between the respective arcing horns of these two sub-assemblies, said thermal sub-assembly comprising a single piece simultaneously forming a corn e of arcing, electrical connection between the terminal and the bimetallic strip and support for the bimetallic strip, the latter being welded to said one-piece piece, said thermal sub-assembly being characterized in that said one-piece piece (4) is obtained by cutting d '' a bi-material plate, of which a first material is a good conductor and the second is suitable for the good formation of an electric arc, then folding so that a first part (4A) of this part, entirely resulting from said first material, form electrical connection between the terminal (2) and the bimetallic strip (3), and a second part of this part (4B), entirely resulting from said second material, form horn of arc formation. Thermal sub-assembly according to claim 1, characterized in that said first material of said bi-material plate is copper and the second material of this plate is steel. Thermal sub-assembly according to claim 1 or 2, characterized in that a portion (35) of the first part (4A) of said one-piece piece (4) is cut so that only one end of this portion is linked the rest of said part, the bimetallic strip (3) being welded to said cut portion. Thermal sub-assembly according to claim 3, characterized in that the end of the junction with the rest of the monobloc piece (4) of the cut portion (35) is located near the junction between the first (4A) and second ( 4B) parts of said one-piece part. Thermal sub-assembly according to claim 3 or 4, characterized in that the end (36; 136) of said cut portion (35; 135) is centered relative to the longitudinal axis (AA) of said second part (4B ; 104B) of the one-piece part (4; 104). Thermal sub-assembly according to any one of claims 3 to 5, characterized in that said first part (4A) comprises a first sub-part (31), extending horizontally and adapted to cooperate with a terminal cage (6 ), then, after a bend downwards, a second substantially vertical sub-part (32), then, offset laterally, a third sub-part (34) describing a U open upwards, said cut portion being linked to the end of the latter. Thermal sub-assembly according to claim 6, intended to be integrated into the phase circuit of a single-pole and neutral circuit breaker, characterized in that the direction of the lateral offset between said second (32; 132) and third (34; 134) sub-parts of the first part (4A; 104A) of the one-piece part (4; 104) is chosen as a function of the position to the right or left with respect to the circuit breaker of said phase circuit, and a portion of said one-piece part, extending from one side of a transverse axis (BB) and centered with respect to a longitudinal axis (AA), remains identical whatever the position of said phase circuit, while the portion of said piece extending from the other side of said transverse axis (BB) is offset on one side or the other of said longitudinal axis (AA), symmetrically, according to the position to the right or to the left of the phase circuit. Circuit breaker housing adapted to receive a thermal sub-assembly according to any one of claims 3 to 7, characterized in that it comprises means for immobilizing (21, 22 and 27, 28) of said one-piece piece (4) , at least two (22 and 27,28) of said immobilization means acting on said one-piece piece between the terminal (2) and the cut-out portion (35) for supporting the bimetallic strip, at different places along the length of said piece. Circuit breaker box according to claim 8 adapted to receive a thermal sub-assembly according to claim 6, characterized in that said immobilization means (21, 22 and 27,28) intervene at the level of the first part (4A), a first immobilization means (21) acting on the first sub-part (31) thereof, a second immobilization means (22) intervening on its second sub-part (32) and a third immobilization means (27 , 28) intervening on its third sub-part (34). Monobloc piece for thermal subassembly according to any one of Claims 1 to 7, characterized in that, by cutting out a portion (31, 32) of said first part (4A) of this piece, it can be integrated into the phase circuit of a unipolar and neutral differential circuit breaker, in which it plays both the role of bimetallic strip support and that of arc-forming horn, a transverse connection resulting from the primary phase winding of said differential circuit breaker can be welded to the free end of the remaining portion (32, 34) of said first part (4A) of the part.

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