FR2999793A1 - MOBILE CONTACTS SUPPORT SHAFT IN AN ELECTRIC CURRENT CUTTING APPARATUS, AND CURRENT CUTTING APPARATUS COMPRISING SAME, IN PARTICULAR A CONNECTION CIRCUIT BREAKER. - Google Patents

Abstract

The present invention relates to a shaft (8) for supporting the movable contacts (7) in an electric current breaking device, said apparatus being housed in an insulating housing and comprising at least one unipolar assembly (2,3,4,5) and a control mechanism (1), said unipolar assembly having a break chamber enclosing a fixed contact, a movable contact (7) supported by said shaft (8), an arc extinguishing device, said shaft (8) can be brought by said control mechanism (1), manually or automatically, in an open position of the movable contacts of the different subsets in which position the fixed contacts and the movable contacts are separated, or a so-called closed position of the apparatus in which the movable contacts are respectively in contact with the fixed contacts, this shaft (8) being characterized in that it comprises an elongated monobloc piece forming a shaft, said piece being made in one insulating material, said shaft (8) being articulated relative to the base of the apparatus about an axis extending substantially parallel to its longitudinal direction, said shaft (8) having mechanical connection means (45,46) to the above-mentioned control mechanism (1), said shaft (8) comprising, for each phase or neutral subassembly (2,3,4,5), means for holding and positioning (20 to 24) the contact mobile (7) and holding means and positioning (34 to 37) of the contact pressure spring (18) associated with the movable contact (7).

Description

MOBILE CONTACTS SUPPORT SHAFT IN AN ELECTRIC CURRENT CUTTING APPARATUS, AND CURRENT CUTTING APPARATUS COMPRISING SAME, IN PARTICULAR A CONNECTION CIRCUIT BREAKER.

TECHNICAL FIELD The present invention relates to low-voltage electrical power cut-off devices in general, and in particular electrical power cut-off devices installed at home and commonly known as "branch circuit breakers".

STATE OF THE PRIOR ART Devices for breaking the electrical current are known, said apparatuses being housed in an insulating casing and comprising at least one unipolar assembly and a control mechanism, said unipolar assembly comprising an insulating base supporting a breaking chamber intended for ensuring confinement of the cut-off, said chamber containing a fixed contact, a movable contact supported by a movable contact-carrier shaft, an arc extinguishing device, said control mechanism being able to be brought manually or automatically into a position of opening of the contacts via a trip bar, said control mechanism comprising a shaft adapted to drive the movable contacts between a so-called open position of the apparatus in which the fixed contacts and the movable contacts are separated, and a so-called closed position of the apparatus in which the fixed contacts are respectively in contact with each other. c mobile contacts.

On current products, the shaft supporting the movable contacts is constituted by several parts each providing different functions. These parts comprise a square section axis, metallic, intended to ensure the transmission of forces between the different subassemblies, a part called "neutral coil" mounted around said axis and carrying the neutral moving contact and the neutral contact pressure spring. this piece also supporting the fixing of the mechanical return spring of the axis in the open position of the contacts, this part also ensuring the bearing function with the base of the device on the left side. These parts also include one to three pieces called "bobina phase" (one for the single-phase version, three for the three-phase version), each of these parts carrying a phase moving contact and a phase contact pressure spring, as well as a piece of transmission of forces supporting a linkage, this part also ensuring the function to overcome with the base of the device on the right side, and finally one to three parts for the reset of the thermal trip units (one for the single-phase version and three for the three-phase version.All these pieces represent a total of five to nine pieces.This large number of parts generates a high cost, mounting games penalizing the chains of dimensions, dispersions, and a complicated assembly of the In addition, the fact of transmitting the forces by a metal axis causes isolation problems.

SUMMARY OF THE INVENTION The present invention solves these problems and proposes a support shaft of the movable contacts as well as a device for breaking the electric current comprising it, in particular a branch circuit breaker, said shaft being of simple design, presenting a cost of reduced manufacture, and whose assembly is facilitated. For this purpose, the subject of the present invention is a shaft for supporting the movable contacts in an electrical breaking device, this apparatus being characterized in that it comprises an elongated monobloc piece forming a shaft, said part being made of an insulating material. , said shaft being articulated relative to the base of the apparatus about an axis extending substantially parallel to its longitudinal direction, said shaft having mechanical connection means to said control mechanism via transmission means said shaft comprising, for each phase or neutral subassembly, means for holding and positioning the moving contact and means for holding and positioning the contact pressure spring associated with the moving contact.

Thanks to these characteristics, a single piece is used to perform several functions, resulting in a simplified design of the apparatus, a reduction in the number of mounting sets, which favors the side chains, a reduction of the dispersions, as well as easier mounting of the device.

According to a particular characteristic, this shaft comprises so-called resetting means constituted by particular forms of the shaft, able to allow rearming after an opening on a fault, of the different thermal triggers respectively belonging to the different phase subsets mentioned above. Thus, according to these characteristics, the number of parts used is further decreased, a single piece being used to replace the five to nine pieces of the previous solution. According to another characteristic, this shaft comprises on each side of each of the zones intended to receive a movable contact and its associated contact pressure spring, portions whose shape is intended to perform a baffling intended to reinforce the isolation. between the different electrical phases of the device. According to another characteristic, this shaft comprises, on either side of each of the zones intended to receive a movable contact and its associated contact pressure spring, parts whose shape is intended to ensure the rigidity of the shaft and the transmission of the mechanical torque throughout the shaft. According to another characteristic, the aforementioned mechanical connection means are located in the vicinity of one end of said shaft. Thus, the point of application of the efforts of the mechanics has been positioned at best to distribute the forces and limit the bending of the shaft.

According to another characteristic, the aforementioned mechanical connection means comprise an axis belonging to the shaft, around which is rotatably mounted one of the ends of a connecting rod whose opposite end is mechanically connected to the control mechanism.

According to another characteristic, the above-mentioned holding and positioning means of each movable contact comprise a recess provided in the shaft intended to receive the movable contact, means of articulation of the movable contact with respect to the aforementioned shaft, provided in FIG. part on the shaft and partly on the movable contact, and a contact pressure spring placed inside the shaft so as to be supported by one of its ends on the shaft, and by its opposite end, on the movable contact so as to exert the aforementioned contact pressure, and retaining means provided in part on the shaft and in part on each movable contact capable of preventing relative movement between the movable contact and the shaft after mounting said spring, in a direction substantially parallel to the longitudinal direction of the main part of the movable contact and in a direction substantially perpendicular to the plane of this part main.

According to another characteristic, the or each movable contact comprises, in the vicinity of one of its ends, and on either side of said movable contact, a substantially ergonomically shaped pin portion adapted to cooperate with a recessed portion of shape. substantially corresponding to the shaft, except that one of the sides of the recess is formed by a portion having a substantially rounded surface, such that after the insertion of the lugs of said movable contact in the corresponding recess in a direction inclined relative to the surfaces of the recess, followed by a slight rotation of the movable contact around this rounded surface until the walls of the lugs are brought in abutment against the corresponding surfaces of the recess, then commissioning of the contact pressure spring in the shaft, the aforementioned relative displacement of the movable contact relative to the shaft is prevented.

According to another characteristic, the positioning and holding means of each contact pressure spring comprise for each spring, a recess provided in the shaft located opposite the associated moving contact, and wherein said spring is intended to be introduced, and a stud belonging to the shaft around which is intended to be mounted one of the ends of said spring whose other end is intended to be brought to bear on said movable contact. The present invention also relates to an electrical apparatus for breaking the current, this apparatus being characterized in that it comprises a support shaft 10 of the movable contacts having the aforementioned characteristics taken alone or in combination. According to another characteristic, this apparatus comprising a thermal protection device comprising, on the one hand, an active bimetal capable of producing a heating when an overcurrent occurs above a certain level above the value of the nominal intensity, this heating leading to a thermal release of the control mechanism of the device so as to cause an opening of the contacts, on the other hand, a so-called compensation bimetal, intended to compensate for the variations that the changes In the temperature of the circuit, ambient temperature determines the bimetallic strip being mounted in rotation about a fixed axis, said first one, belonging to a support of the device, the two bimetals being secured to one another at one of their ends by means of a coupling device, this coupling device being deactivated during the occurrence of an overcurrent, this deactivation leads to actuation by the compensation bimetallic strip of the control mechanism, as well as resetting means able to return the hooking device to the activated position when the contacts are opened, this apparatus is characterized in that the axis of rotation of the movable contact carrier shaft and the axis of rotation of the compensating bimetallic strip are brought close to one another and extend substantially parallel to each other, and the movable contact-carrying shaft comprises a so-called first part cooperating with a so-called second part which is integral in rotation with the compensating bimetallic strip, these two parts being arranged relative to each other in such a way that after a tripping of the mechanism, during driving of the movable contact shaft in the direction of the opening of the contacts, the so-called first part rotates the so-called second part and thus the compensating bimetal in a direction opposite to that having triggered the mechanism, until the two bimetallic strips are re-latched relative to one another. According to another characteristic, this apparatus comprises a sub-assembly of cut-off of the neutral and respectively one, two or three subsets of phase cutoff.

According to a particular characteristic, the mechanical connection means are located on the subassembly of cutoff of the neutral. According to a particular characteristic, this device is a branch circuit breaker intended to be located between a meter and a distribution board and is intended to connect a particular to the electrical network. BRIEF DESCRIPTION OF THE FIGURES But other advantages and features of the invention will become more apparent in the detailed description which follows and refers to the accompanying drawings given solely by way of example and in which: FIG. 1 is a partial perspective view , illustrating a plate on which are fixed the various components of a branch circuit breaker according to the invention, - Figure 2 is a perspective view, illustrating a support shaft of the movable contacts of the device, said shaft being equipped with movable contacts, FIG. 2a illustrates the moving contact alone, FIGS. 3, 4 and 5 are perspective views, showing the shaft according to the invention without the moving contacts, respectively in several different orientations, FIG. 6 is a perspective view illustrating the plate of the apparatus, after the mounting of the shaft, FIG 7 is a perspective view, illustrating the shaft according to the invention equipped with movable contacts and contact pressure springs, viewed from below with respect to FIG. 2, FIGS. 8 and 9 illustrate the mounting of the movable contacts in the shaft, respectively for the two figures during assembly and assembly being completed. FIG. 10 is a perspective view illustrating the shaft mounted on the plate and its mechanical connection with the control mechanism; FIG. 11 is a perspective view of the transmission rod alone. FIGS. 12, 13 and 14 are perspective views, illustrating the resetting of the thermal trip units by a support shaft of the moving contacts according to the invention, respectively in the closed position of the apparatus, during rearming of the apparatus and in the reset position of the apparatus, and FIG. 15 is a view identical to FIGS. 12 to 14, but in another orientation showing the contact pressure springs. DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION In FIG. 1 is shown a plate P on which are mounted the various elements of an electrical protection device such as a branch circuit breaker enabling an individual to to be connected to the electrical network, said circuit breaker being intended to be located between a meter and an electrical panel. This assembly is intended to be mounted in an insulating housing (not shown), this housing having an opening for the passage of a lever M for the operation of the apparatus and having access openings to input terminals and to output terminals intended to be electrically connected respectively to the meter and to the electrical panel. This device is of the multipole type and mainly comprises a control mechanism 1 and, according to this particular embodiment, four unipolar assemblies 2, 3, 4, 5 comprising three assemblies 2, 3, 4 intended to cut a phase and an assembly. unipolar 5 for the neutral cut, each of these sets being associated an input terminal and an output terminal. Each unipolar assembly 2, 3, 4, 5 comprises a fixed contact not shown electrically connected by a conductor in the form of a braid to one of the terminals, and a movable contact 7 electrically connected by a flexible conductor to the other of the terminals. This movable contact 7 is supported by a shaft 8 movable contact holder common to all unipolar assemblies, and adapted to be rotated by a control mechanism 1 between a position in which the fixed and movable contacts 7 are open and a position in which the fixed and mobile contacts are closed. The control of the opening of the contacts can be effected either manually by the operation of a lever M belonging to the control mechanism 1, or automatically by means of a protective device comprising a magnetic protection device 9 against instantaneous overloads of electric current, and a thermal protection device 10 against prolonged overloads of electric current. Thus, each unipolar phase assembly 2,3,4 comprises an electric circuit comprising, mounted in series with the fixed and movable contacts 7, a thermal protection device 10 and a magnetic protection device 9, these two protection devices being able to be mounted in series or in parallel depending on the size. These two protection devices 9, 10 each comprise an actuator able to act on a so-called transfer bar 11, said bar extending substantially parallel to the alignment direction of the unipolar assemblies 2, 3, 4 and being intended to transmit the triggering order or opening of the contacts to the control mechanism 1 so as to drive the shaft 8 movable contact carrier in an open position of the contacts 7 of all unipolar assemblies. This apparatus also comprises a differential protection device 13 comprising a differential relay capable of sending an opening command to the control mechanism 1 during an imbalance caused by a receiver having a fault current.

According to the invention, and as illustrated in FIGS. 2 to 5, this shaft 8 is constituted by a one-piece part made of an insulating material such as plastic, this shaft being intended to be rotatably mounted on a plate P, such illustrated in Figure 6, by means of two bearing shafts 14,15 located at both ends of said shaft, and intended to cooperate respectively with two openings 16 provided in two supports belonging to the plate. This shaft 8 comprises, located opposite each sub-assembly neutral cutoff or 2,3,4,5 phase when the shaft 8 is mounted on the plate P, means for positioning and maintaining a contact mobile 7 as well as means for positioning and maintaining a contact pressure spring 18 associated with said moving contact 7. As illustrated in FIG. 2a, each moving contact 7 comprises a first so-called main portion 7a from which extends a second so-called secondary portion 7b, extending in a plane substantially perpendicular to the plane of the first portion, this first portion having at one of its ends, a contact pad 19, and at its opposite end, two pins 20,21 extending on either side of this end, these two lugs 20,21 being intended to cooperate with two corresponding openings 22,23 provided in the shaft 8 as will be explained in the following. These positioning and holding means comprise, for each movable contact 7, a recess 24 intended to receive the main parts 7a and 7b of the secondary mobile contact 8, and two recessed portions 22, 23 of complementary shape provided in the shaft 8 and intended to cooperate with the two aforementioned lugs 20,21 so as to firmly hold the movable contact 7 in its housing 24 after mounting the corresponding contact pressure spring 18 in the shaft 8. Thus, the two lugs 20,21 present a substantially parallelepipedal shape and are intended to cooperate respectively with the two aforesaid openings or recess portions 22,23 of substantially complementary shape to those of the aforementioned pins, these two recess portions being provided in the shaft 8 and each having three successive walls 26,27,28 (FIG. 8) intended to be placed in abutment against three successive walls 29,30,31 of the corresponding pin in positio n rise of the movable contact 7, position in which the movement of this movable contact 7 in the longitudinal direction of the movable contact 7 and in a direction perpendicular to the plane of the surface of the main part 7a of the movable contact 7 in one direction only is blocked , the displacement of the movable contact 7 in the other direction being prevented by a retaining element 32 adapted to bear against another wall 33 of the lug when the movable contact 2 is put in place. The surface 32a of this retaining element 32 intended to cooperate with the aforementioned wall 33 of the corresponding lug 20,21 is rounded, so as to allow a slight rotation of the movable contact 7 with respect to this surface during its introduction, as this will be explained in the following.

Thus, during assembly of the movable contact, the lugs 20, 21 are introduced into the corresponding recessed portions 22, 23 diagonally, as illustrated in FIG. 8, that is to say in a direction inclined with respect to 26,27,28 walls of the recessed portions, then when the lugs 20,21 are completely introduced into the corresponding recessed portions 22,23, a slight rotation is made to the moving contact 7 with respect to the rounded surface 32a of the elements retaining 32, to bring the first three aforementioned surfaces 29,30,31 lugs 20,21 bearing against the three corresponding surfaces 26,27,28 of the recessed portions, said lugs then being retained inside the parts recessed by the elasticity of the retaining elements 32, as shown in Figure 9. Then, a contact pressure spring 18 is introduced into a recess 34 (Figs.2 and 15) provided for this purpose in the tree 8 and located at the top the upper part of the shaft when it is mounted on the plate P. As illustrated in Figure 3, inside each recess 34 provided in the shaft 8 to receive the spring 18, is provided a stud 36 intended to receive one 18a of the ends of the spring 18, the other end 18b is intended to bear on a particular shape located on the movable contact, this second end 18b being mounted around a boss 37 located on the face the moving contact opposite to that receiving the pellet 19, so as to achieve the contact pressure. As this is also illustrated in FIG. 3, this shaft 8 comprises, on either side, zones of the shaft 8 intended to receive the movable contacts 7, forms 38 effecting a baffling of the shaft 8 intended to realize the electrical sealing between the phases. As illustrated in Figure 4, this shaft 8 also comprises between the aforementioned zones, parts 39 whose shape is intended to ensure the rigidity of the shaft 8 and the transmission of torque all along the shaft. As illustrated in FIG. 5, this shaft 8 also comprises, in the abovementioned zones, nozzle portions 40 capable of cooperating with parts 41 integral respectively with the different bimetals of compensation so as to carry out the resetting of the thermal trip devices after the contact opening following an overcurrent, as will be explained in more detail in the following with reference to FIGS. 12 to 14.

In Figure 12, the mechanism 1 of the apparatus is in the closed position not triggered. In this position, the two bimetals 42,43 are secured by an attachment device 44, and the two reset parts respectively 40 and second 41 first, are distant from each other. When an overcurrent occurs which exceeds the mentioned calibration limit, but does not reach the excessively high values as is the case for overconsumption in the controlled installation, said overcurrent causes a greater heating of the bimetal 43. this results in a differential deflection between the active bimetal 43 and the bimetallic strip 42 which makes it possible to deactivate the attachment device 44. The return spring comes into action so as to drive the part supporting the bimetallic bimetallic strip and thus the bimetallic strip compensation, in rotation about the axis said first, to a position in which it acts on the transfer bar. In this position illustrated in FIG. 13, the so-called first 40 and second 41 parts are in a close position, but not in contact, which corresponds to an instantaneous position in which the part 41 integral with the compensating bimetallic strip 42 has finished act on the transfer bar 11, but that the opening of the contacts 7 has not yet occurred. This has the effect of triggering and rotating the contact carrier 8 towards a position in which the contacts are open, this position being illustrated in FIG. 14. During this rotation of the movable contact holder shaft 8 in the counterclockwise, towards the open position of the fixed and movable contacts 7, the so-called first piece 40 comes into contact with the so-called second piece 41 and drives the latter and thus the compensating bimetallic strip 42 in a clockwise rotation up to to restore the attachment between the two bimetals 42,43, which corresponds to a reset position of the bimetallic strip shown in FIG. 14. As illustrated in FIGS. 5 and 10, this shaft 8 for supporting the movable contacts 7 is connected mechanically to the control mechanism 1 of the apparatus via a transmission rod 45, illustrated in Figure 11, this connecting rod being connected in an articulated manner by one of its ends, to an axis 46 belonging to the shaft 8 located opposite a movable contact 7, and being connected at its opposite end mechanically to the control mechanism. In this particular embodiment of the invention, the mechanical connection between the shaft 8 and the mechanism 1 is made on a part of the shaft comprising the movable contact corresponding to the subassembly of neutral 5. Thus, according to the invention, one piece supports all the functions, namely the positioning and the maintenance of the contacts, the positioning and the maintenance of the contact pressure springs, the linkage, the left and right bearings, the transmission of forces and according to a particular embodiment of the the invention the resetting of the thermal trip units.

Of course, the invention is not limited to the embodiment described and illustrated which has been given by way of example. Thus, the invention applies to any electrical switching device comprising a support shaft of the movable contacts. On the contrary, the invention comprises all the technical equivalents of the means described and their combinations if they are carried out according to its spirit.

Claims (14)

REVENDICATIONS1. Supporting shaft for movable contacts in an electrical switchgear, said apparatus being housed in an insulating housing and comprising at least one unipolar assembly and a control mechanism, said unipolar assembly comprising a breaking chamber, said chamber enclosing a fixed contact, a movable contact supported by said movable contact support shaft, and an arc extinguishing device, said movable contact support shaft being movable by said control mechanism, manually or automatically, into an open position movable contacts of the different subassemblies in which position the fixed contacts and the movable contacts are separated, or a so-called closed position of the apparatus 15 in which the movable contacts are respectively in contact with the fixed contacts, characterized in that it comprises an elongated monobloc piece forming a shaft, said part being made of an insulating material said shaft (8) being articulated relative to the base of the apparatus about an axis extending substantially parallel to its longitudinal direction, said shaft (8) having mechanical connection means (45, 46) to said control mechanism (1) via transmission means (45), said shaft (8) comprising, for each phase or neutral subassembly (2,3,4,5), means for holding and positioning (20 to 24) the movable contact (7) and means for holding and positioning (34,35,36,37) the contact pressure spring (18) associated with the movable contact (7). 2. Shaft according to claim 1, characterized in that it comprises so-called resetting means (40,41) constituted by particular shapes of the shaft (8), able to allow resetting after a fault opening, different thermal triggers respectively belonging to the various subset of said phase (2,3,4). 3. Shaft according to claim 1 or 2, characterized in that it comprises on each side of each of the areas intended to receive a movable contact (7) and its associated contact pressure spring (18), parts (38) whose shape is intended to perform a baffling to enhance the electrical isolation between the different electrical phases of the device. 4. Shaft according to any one of claims 1 to 3, characterized in that it comprises, on either side of each of the areas for receiving a movable contact (7) and its associated contact pressure spring ( 18), portions (39) whose shape is intended to ensure the rigidity of the shaft (8) and the transmission of the mechanical torque along the shaft. 5. Shaft according to any one of the preceding claims, characterized in that the aforementioned mechanical connection means (45) are located in the vicinity of one end of said shaft (8). 6. Shaft according to any one of the preceding claims, characterized in that the aforementioned mechanical connection means (45) comprise an axis (46) belonging to the shaft (8), around which is rotatably mounted one of ends of a connecting rod (45) whose opposite end is mechanically connected to the control mechanism (1). 7. Shaft according to any one of claims 1 to 6, characterized in that the above said holding and positioning means of each movable contact (7) comprise a recess (24) provided in the shaft (8) intended to receive the movable contact (7), hinge means (32,33) of the movable contact relative to the aforementioned shaft, provided in part on the shaft and in part on the movable contact, and a contact pressure spring (18) placed inside the shaft so as to be supported by one of its ends on the shaft, and by its opposite end, on the movable contact so as to exert the above-mentioned contact pressure, and retaining means (26 to 32) provided in part on the shaft (8) and in part on each movable contact (7) able to prevent relative movement between the movable contact and the shaft after mounting said stress (18). ), in a direction substantially parallel to the longitudinal direction of the main portion cipal (7a) of the movable contact (7) and in a direction substantially perpendicular to the plane of this main part (7a). 8. Shaft according to claim 7, characterized in that the or each movable contact (8) comprises, in the vicinity of one of its ends, and on either side of said movable contact, a pin portion (20, 21) of substantially parallelepipedal shape adapted to cooperate with a recess portion of substantially corresponding shape (22,23) of the shaft (8), except that one of the sides of the recess is formed by a portion (32). ) having a substantially rounded surface (32a), such that after insertion of the lugs (20,21) of said movable contact (7) into the corresponding recesses in a direction inclined with respect to the surfaces of the recess (26). , 27,28), followed by a slight rotation of the movable contact (7) around this rounded surface until the walls (29,30,31) of the lugs (20,21) are brought in abutment against the corresponding walls (26,27,28) of the recessed parts (22,23), then a commissioning of the press spring ion contact (18) in the shaft (8), the aforementioned relative displacement of the movable contact (7) relative to the shaft is prevented. 9. Shaft according to any one of claims 1 to 8, characterized in that the means for positioning and holding each contact pressure spring (18) comprises for each spring, a recess (34) provided in the shaft (8), located opposite the associated moving contact (7), and wherein said spring is intended to be introduced, and a stud (36) belonging to the shaft (8) around which is intended to be mounted one of ends of said spring (18) whose other end is intended to be brought into abutment on said movable contact (7). Electrical apparatus for breaking the current, characterized in that it comprises a shaft (8) for supporting the movable contacts according to any one of the preceding claims. 11. Apparatus according to claim 10, comprising a thermal protection device comprising, on the one hand, a bimetal said active (43) capable of producing a heating when overcurrent occurs above a certain level beyond- above the value of the nominal intensity, this heating leading to a thermal release of the control mechanism of the apparatus so as to cause an opening of the contacts, on the other hand, a bimetal said compensation (42), intended to to compensate for the variations that the changes in the ambient temperature determine in the temperature of the circuit, the bimetallic strip being mounted in rotation about a fixed axis, said first belonging to a support of the apparatus, the two bimetallic strips (42,43) being secured to one another at one of their ends by means of a coupling device (44), this coupling device being deactivated during the occurrence of an overcurrent, this deactivation e resulting in actuation by the compensating bimetallic strip (42) of the control mechanism (1), as well as resetting means (40,41) able to return the hooking device (44) to the activated position during the opening characterized in that the axis of rotation of the movable contact-carrying shaft (8) and the axis of rotation of the compensating bimetallic strip (42) are brought into proximity with one another and extend substantially parallel to each other, and in that the movable contact-carrying shaft (8) comprises a so-called first piece (40) cooperating with a so-called second piece (41) integral in rotation with the bimetal the two parts (40,41) being arranged relative to each other in such a way that after a triggering of the mechanism (1), during driving of the shaft movable contacts (8) in the direction of the opening of the contacts, said first part (40) rotates said second part (41) and thus the compensation bimetallic strip (42) in a direction opposite to that which triggered the mechanism, until the two bimetallic strips (42, 43) are re-latched relative to one another. 12. Apparatus according to claim 10 or 11, characterized in that it is of the bipolar, three-pole or four-pole type, and in that it comprises a sub-assembly of cut-off of the neutral (5) and respectively one, two or three subsets of phase cleavage (2,3,4). 13. Apparatus according to claim 12, characterized in that the mechanical connection means (45,46) are located on the neutral cutoff subassembly (5). 14. Apparatus according to any one of claims 10 to 13, characterized in that it is a branch circuit breaker intended to be located between a meter and a distribution board and intended to connect a particular electrical network. 10 15 20 25 30