EP0996959A1

EP0996959A1 - Circuit breaker for low voltage alternating electric installation

Info

Publication number: EP0996959A1
Application number: EP99919323A
Authority: EP
Inventors: Roger Dumont
Original assignee: Socomec SA
Current assignee: Socomec SA
Priority date: 1998-05-14
Filing date: 1999-05-12
Publication date: 2000-05-03
Anticipated expiration: 2019-05-12
Also published as: CN1118838C; DE69920370D1; FR2778789A1; WO1999059177A1; EP0996959B1; FR2778789B1; CN1269052A; US6278619B1

Abstract

The invention concerns a disconnecting appliance, such as a switch, a fuse-disconnecting switch or breaker-reversing switch, having a novel arrangement of fixed and moving contacts promoting contact surface self-cleaning and increasing contact force for the same contact force applied by the cam. Moreover, it comprises a newly designed cam for actuating the mobile contacts to optimise to the maximum the operating conditions when engaging and releasing. Said appliance is characterised in that the moving contacts (35, 36) comprise two contact surfaces (38) arranged in substantially perpendicular planes, corresponding with those (27) of the fixed contacts (31, 31' and 33, 33'), each moving contact (35, 36) moving in radial translation relative to the control shaft (23) along a direction (F) substantially perpendicular to a straight line passing through its two contact surfaces (38). The cam (50) comprises a flow track (56) and a return track (57), respectively corresponding to engaging and releasing, to guide a driving pin (45) integral with a moving element (40) coupled to said moving contacts, said moving element being arranged to be translated radially relative to the control shaft (23). The invention is applicable to any industrial electrical installation.

Description

ELECTRICAL SWITCHING APPARATUS FOR LOW-VOLTAGE ELECTRICAL INSTALLATION

The present invention relates to an electrical cut-off device for a low-voltage AC electrical installation provided with at least two phase conductors with or without neutral conductor, comprising a cut-off module per conductor and a control module provided with a mechanism actuation of said breaking modules, each breaking module comprising at least one input terminal connected to a fixed contact, one output terminal connected to one fixed contact, two other fixed contacts connected to each other by a bridge or a fuse and forming with the other fixed contacts two pairs of fixed contacts and two movable contacts respectively associated with a pair of fixed contacts, an engaged position and a triggered position, the control module comprising at least one control axis coupled to an operating handle, this axis passing through said cut-off modules and carrying at least one cam coupled to at least one mobile unit in blow translation lé to said movable contacts to be moved from a first stable position called the engaged position to a second stable position called the triggered position.

These breaking devices commonly called switches, fuse switches or change-over switches are intended to distribute energy to electrical installations or to control industrial equipment in low AC voltage, for example 380 V, and in a current range of a few tens to a few thousand amps. The so-called double breaking devices have two movable contacts per pole or breaking module. Most often, the mobile contacts consist of a rectilinear bar which performs between its two stable positions a pure translational movement and the fixed contacts of the same pair are arranged in the same plane parallel to said mobile contact. The translational movement of the movable contacts is traditionally obtained by a cam integral at its center with the control axis of the cut-off modules. The cam may have an almost oval shape and have a guide path on its edge. In this case, each movable contact is connected to a movable assembly provided on either side of the control axis and applied against the edge of the oval cam by means of a spring. The rotation of the cam generated by the rotation of the control axis drives the moving element in a radial translational movement transmitted simultaneously to the corresponding moving contact. The almost oval shape of the cam is generally optimized to allow a sudden cut and an optimal maneuvering effort. The cam can also have a round shape on which the moving parts are fixed at eccentric points, thus forming a connecting rod-wheel system. Thus, the rotation of the cam also causes the radial translation of the moving element which is transmitted to the corresponding moving contact.

The known breaking devices described briefly above have many drawbacks. Because the movable contacts perform a pure translational movement, there is no friction between the movable contacts and the fixed contacts at the time of engagement and tripping. Therefore, there is no self-cleaning of the contact surfaces. This lack is detrimental to the quality of the electrical contact. In particular, the contact resistance increases with the number of operations carried out and the number of electric arcs being established between the fixed and mobile contacts. The deterioration in the quality of the electrical contact causes heating of the contact surfaces and of the device in general, inducing losses by the Joules effect, as well as a reduction in the service life of both the contacts and the device. On the other hand, in conventional devices, the number of parts is relatively large. It is necessary, in particular, to have several intermediate conductive parts to make the complete circuit from the input terminal to the output terminal. These parts being commonly made of copper, the cost price of the cut-off modules remains relatively high. Furthermore, the force applied to the movable contact corresponds to that applied by the cam secured to the control pin itself secured to the operating handle. However, the fact that each rectilinear movable contact cooperates with two fixed contacts arranged in the same plane, the force applied to each fixed contact corresponds to half of the force transmitted by the cam. This implies, to increase the force at the contacts, to increase the maneuvering force on the handle, which is opposite to the objective sought upon engagement. In addition, in conventional switching devices, the speed and the distance of movement of the movable contacts as a function of time are identical to the engagement and the triggering, which is detrimental to an optimization of the physical conditions in one and the 'other stable positions. In fact, when switching on, we are looking for the lowest possible maneuvering effort as well as the fastest possible switching speed. On the other hand, when triggered, an abrupt cut-off is sought to avoid as much as possible the appearance of electric arcs as well as good resistance to a effort equal to three times the operating effort, commonly called 3F and defined by an international standard.

Some publications describe electrical switching devices arranged to create friction between the fixed and movable contacts at the time of engagement.

This is the case, in particular, in the publications EP-A-252,285, EP-A-105,817 and CH-A-352,024. However, none of them provides for a particular arrangement of the contacts making it possible to increase the effort of contact between them, nor different paths of the movable contacts for switching on and off in order to optimize the operating conditions.

In publication EP-A-252,285, it is a circuit breaker limited to low currents (less than 32A) for domestic applications and provided with a single breaking module and not with an industrial switch provided with several cut-off modules. In addition, the contact surfaces provided on the fixed contact and the movable contact are coplanar. It is the movement transmission mechanism between the circuit breaker lever and the movable contact that generates a friction movement between the two contacts.

In publication EP-A-105 817, it is a multi-stage switch limited to currents from 25 to 32A and the cam mechanism of which is solely intended to ensure self-cleaning of the contacts by means of an auxiliary cam which controls a carriage moving the movable contacts by friction on the fixed contacts. The contact surfaces provided on these fixed and mobile contacts are also coplanar.

In publication CH-A-352 024, it is a switch with two movable contacts, the contact surfaces of which are also coplanar, controlled by a rotary central cam. The approach movement of the movable contacts is made at an angle of 20 to 30 ° which induces, at the time of contact, a pressure and a self-cleaning friction on the contacts.

The object of the present invention is to overcome these drawbacks by proposing a switching device having a new geometry of fixed and mobile contacts promoting self-cleaning of the contact surfaces but above all increasing the contact force for the same force applied by drug. In addition, the switching device proposed has a newly arranged cam to meet the various characteristics required for switching on and off so as to optimize the operating conditions as much as possible.

This object is achieved for a switching device as defined in the preamble and characterized in that each movable contact comprises two contact surfaces arranged in substantially perpendicular planes, in that the fixed contacts of the same pair are arranged in planes substantially perpendicular so that their respective contact surface is placed opposite the corresponding contact surface provided on said movable contact when it is in the engaged position and in that each movable contact moves in radial translation relative to the control axis in a direction substantially perpendicular to a straight line passing through its two contact surfaces.

In a preferred embodiment, each movable contact comprises two end branches arranged on either side of a middle branch and forming an angle of approximately 45 ° relative to said middle branch, the contact surfaces being provided on the two end branches.

The movable assembly advantageously consists of a substantially rectangular frame extending transversely through said cut-off modules and arranged in an inclined plane substantially parallel to the control axis.

The frame may include at least two parallel walls, oriented radially with respect to the control axis and arranged to slide along two corresponding walls made in the housing of said device to guide said frame in translation.

In the preferred form of reahsation, the frame comprises, for each corresponding movable contact, a window oriented substantially perpendicular to the control axis and a return spring housed in this window to urge said movable contact towards the fixed contacts.

The frame also comprises at least one notch intended to receive said cam, at least one wall of this notch comprising a drive finger substantially parallel to the control axis and engaged in at least one track provided in said cam.

Preferably, the cam comprises, for each movable assembly, a non-circular groove, delimited by an internal wall close to the control axis and an external wall remote from the control axis, these walls being arranged to guide said finger drive, respectively on switching on and off.

The bottom of the groove advantageously comprises different reliefs arranged to define, respectively with the internal and external walls, two separate tracks, namely a forward track for engagement and a return track for triggering.

In the preferred form of reaction, the outward track comprises a first substantially straight portion and a second circular portion of small radius eccentric relative to the control axis and the return track comprises a first circular portion of constant radius centered on the axis and a second circular part whose radius is less than said constant radius.

Advantageously, the second part of the outward track communicates with the first part of the return track by a shoulder.

This cam advantageously comprises a central barrel integral in rotation with the control axis and sliding on the latter and the notch provided in the frame of the moving assembly has a width greater than that of the cam allowing it to be moved axially corresponding to the differences in relief of the back of the throat.

In the preferred reahsation, the barrel has at least one of its free ends a cam profile cooperating with at least one lug provided at least in the housing of said device and oriented radially with respect to the control axis and the axis of control carries a return spring arranged to maintain the cam profile in abutment on said lug.

In a variant of reahsation, the groove can be extended, in a direction opposite to that of the outward and return tracks, by a test track, framed by the walls internal and external, this track being circular, close to the control axis, of constant radius centered on this axis.

In this variant, the cam has on its rear face a circular groove close to the control axis and centered on this axis and the frame of the mobile assembly comprises a guide shoe 46 disposed opposite the drive finger 45 and arranged to be housed in said groove when the device is in the test position.

The present invention and its advantages will be better understood in the following description of a form of reahsation given by way of nonlimiting example and with reference to the appended drawings, in which:

FIG. 1 represents a perspective view of a switching device according to the invention, the cover being removed, the device being in the tripped position,

FIG. 2 is a partial plan view, the main elements being shown in transparency, the apparatus being in the released position,

FIG. 3 is a partial perspective view of the device in the triggered position,

FIG. 4 is a partial plan view, the main elements being shown in transparency, the apparatus being in the engaged position,

FIG. 5 is a partial perspective view of the device in the engaged position,

FIG. 6 is a partial plan view, the main elements being shown in transparency, the apparatus being in the test position,

FIG. 7 is a partial perspective view of the apparatus in the test position,

FIG. 8 is a partial perspective view showing the rear of the cam, and

- Figure 9 is a partial perspective view showing a detail of the housing. With reference to FIG. 1, the switching device 1 according to the invention comprises, in the example shown, a control module 2 and three switching modules 3. This device is intended for a three-phase electrical installation, ie provided with three phase conductors, but could be adapted to any other installation. The cut-off modules 3 are either made up of independent boxes, juxtaposed and assembled by any known means, or grouped together in a single box 4. Each cut-off module 3 is associated with a conductor of said installation and comprises in a known manner a terminal input 30 connected to a fixed contact 31, an output terminal 32 connected to a fixed contact 33, two other fixed contacts 31 ', 33' (not shown in this figure) secured to the cover of the device, connected to each other by a conductive bridge 34 (not shown in this figure) or a fuse and forming with the other fixed contacts 31, 33 two pairs of fixed contacts, as well as two movable contacts 35, 36 each associated with a pair of fixed contacts 31, 31 'and 33, 33 'and having two stable positions, an engaged position and a triggered position. Fixed contacts 31, 31 ',

33, 33 ′ each have a contact surface made up of a contact pad 37 and the movable contacts 35, 36 each have two contact surfaces made up of contact pads 38 arranged to bear against the contact pads 37 when the switchgear 1 is in the engaged position. The movable contacts 35, 36 are mounted respectively in two identical movable equipment 40, arranged symmetrically with respect to the axis A of said switching device 1 and movable in translation in two opposite directions and substantially perpendicular to said axis A.

The control module 2 comprises, in a known manner, a housing 20, a transmission axis 21 connected to an operating handle (not shown) accessible outside said housing and coupled by toothed pinions 22, constituting a bevel gear, to a control axis 23 of the movable contacts 35, 36, disposed in the axis A and passing through the cut-off modules 3. Nevertheless, the operating handle can be directly coupled to one of the ends of the control axis 23 according to the configuration which it is desired to give to said switching device. This assembly is possible because, as will be seen below, the operating clearance is located at the level of the control mechanism of the cut-off modules and no longer at the level of the control module. The control axis 23 is connected to each movable contact 35, 36 in order to control them simultaneously in a synchronous and abrupt manner. This control module 2 also includes a snap action device 24 by energy accumulation, connected to said control axis 23 and arranged to cause rapid engagement and tripping of the movable contacts relative to the fixed contacts. This snap action device 24 makes it possible, in a known manner, to avoid the stagnation of electric arcs on tripping, the early initiation of arcs on latching and comprises a spring mounted in such a way that all of the intermediate positions between the latched positions and tripping of the switching device are unstable.

The control axis 23 carries two identical cams 50 each mounted on a barrel 51 which can slide axially with respect to said axis 23. These cams 50 are pushed towards the control module 2 by means of a return spring 52 disposed on the control shaft 23 between a side wall of the housing 4 and the nearest barrel 51. Each cam 50 is arranged to cooperate with the two moving parts 40 so as to move the moving contacts 35, 36 synchronously from their tripped position to their engaged position and vice versa.

Figures 2 to 7 partially illustrate the switching device 1 showing the main parts which constitute the present invention, in different positions. In Figures 2, 4 and 6, the parts are shown in transparency, seen from the end of the control axis 23. In Figures 3, 5 and 7, these parts are shown in perspective. The parts making up said cutting device 1 are almost all symmetrical about the axis A.

The input 30 and output 32 terminals are respectively connected to the fixed contacts 31 and 33. These fixed contacts 31, 33 each consist of a conductive bar folded at right angles, one of the branches being housed in the corresponding terminal and l 'other branch carrying a contact pad 37 for example riveted. The other two fixed contacts 31 ′, 33 ^* consist of a conductive bar folded twice at right angles to form a stair step, one of the branches being housed in the cover of the apparatus and the other branch carrying a contact pad 37. The fixed contacts form two by two pairs of fixed contacts 31, 31 'and 33, 33' whose contact pads 37 are arranged in perpendicular planes. Fixed contacts 31 ', 33' are connected together either by means of a bridge forming a single switch, or by means of a fuse cartridge forming a fuse switch.

The movable contacts 35, 36 consist of a conductive bar comprising two end branches arranged on either side of a middle branch and forming with it an angle of substantially 45 °. Each end branch carries a contact pad 38, for example riveted. The contact pads 38 of the same movable contact are arranged in perpendicular planes and are intended to be in contact with the contact pads 37 of the pair of corresponding fixed contacts, in the engaged position. The movable contacts 35, 36 are mounted respectively in the movable assemblies 40 arranged to move them simultaneously, synchronously, in translation in a direction F perpendicular to a straight line passing through the two contact pads 38.

The bent or possibly rounded shape of the movable contacts 35, 36 as well as the 45 ° docking of the movable contacts relative to the fixed contacts make it possible to ensure, at each engagement and initiation, self-cleaning of the contact pads 37, 38. Indeed, the contact pads 38 are positioned on the contact pads 37 or deviate from them according to the translational movement F which is broken down into a horizontal component FI and a vertical component F2, each component generating friction between the pads 37, 38. Furthermore, the operating force G transmitted to the movable contacts 35, 36 affects the fixed contacts 31, 33 according to the horizontal component Gl and the fixed contacts 31 ', 33' according to the vertical component G2. The angle of said maneuvering force G being 45 °, since it is parallel to the direction F, the components Gl and G2 have a value equal to G / V2, that is to say greater than G / 2 as in the state of the art. So for the same maneuvering effort, the contact effort is increased by 40%. This results in an improvement in the electrical characteristics: the breaking capacity and the short-circuit withstand are substantially improved. On the other hand, the particular construction of the fixed contacts and of the movable contacts makes it possible to halve the total length of copper required, which leads to a reduction in the cost price of the whole of the switching device 1.

The moving parts 40 each consist of a substantially rectangular frame 41 extending in the three cut-off modules and arranged in a plane 10

inclined passing through the control axis 23. This frame 41 has three rectangular windows 42, oriented radially with respect to the control axis 23 and intended to receive the movable contacts 35, 36 of said modules. The width of the windows 42 is slightly greater than that of the movable contacts 35, 36 so as to provide said operating clearance mentioned above. Therefore, the frame 41 is slightly floating relative to the rest of the mechanism. A return spring 43 is provided in each window 42 to hold said movable contacts 35, 36, in their planar central branch, bearing against said frame 41 outward, that is to say distant from the control axis 23, in the direction of the fixed contacts. These springs 43 are centered relative to their window 42 by means of a stud (not visible) provided on the frame 41. This frame 41 also includes two housings 44 also rectangular, intended to receive the two cams 50. On the walls in look of each housing 44 are respectively provided a drive finger 45 oriented parallel to the axis A and a guide shoe 46, each cooperating with the opposite faces of the corresponding cam 50. The width of the housings 44 is approximately equal to twice that of the cams 50, thus allowing them an axial clearance D which will be detailed below. This frame 41 is extended outwards by at least two transverse walls 47 arranged to slide against corresponding transverse walls 48 provided in the housing 4 of the cut-off modules 3 so as to guide said movable element 40 in its translational movement. Each moving element 40 is thus driven by its two fingers 45 guided in the two cams 50 so as to guarantee its displacement in radial translation parallel to the axis A.

Each cam 50 comprises a barrel 51 slidably mounted on the control axis 23 corresponding to the axial clearance D mentioned above. The free end of this barrel

51 has a left cam profile 53 cooperating with two facing lugs 54 respectively provided on the housing 4 (cf. FIG. 9) and the cover (not shown) of said device 1, on the side of the control module 2. This profile of cam 53 allows on the one hand the mechanical coupling of two consecutive drums 51 when two cams 50 are mounted on the control axis 23 and on the other hand the axial movement D of said cams, the function of which will be specified below. The return spring 52 (cf. FIG. 1) maintains this cam profile 53 in abutment on the lugs 54. The cams 50 are arranged to move simultaneously, in synchronism and in translation along F the two moving parts 40 and comprise, at this effect, on the side of the drive fingers 45 two non-circular grooves 55, that is to say the distance to the axis A varies in 11

depending on the angle of rotation, these two grooves being identical and angularly offset by 120 °. The detail which follows relates to a single groove 55 cooperating with the drive finger 45 of a single mobile assembly 40 associated with a single set of mobile contacts 36.

This groove 55 is defined laterally by an internal wall 55a close to the axis A and an external wall 55b remote from the axis A, these walls having the function of guiding the drive finger 45. The bottom of the groove 55 comprises different rehefs defining, respectively with the internal walls 55a and external 55b, two separate tracks 56, 57, also having the function of guiding the drive finger 45: a go track 56 for guiding the finger 45 from the position triggered to the engaged position and a return track 57 for guiding finger 45 from the engaged position to the triggered position.

The operation of the cam 50 associated with the drive finger 45 is detailed with reference to Figures 2 and 3 showing the triggered position and Figures 4 and 5 showing the engaged position.

During the engagement, that is to say to pass from the triggered position (cf. Fig. 2 and 3) to the engaged position (cf. Fig. 4 and 5), one seeks to obtain an operating force as low as possible and to ensure good electrical contact between the movable contacts and the fixed contacts. The outward track 56 therefore has two parts (see for clarity in FIG. 4 in which the parts are hatched): a first substantially straight part 56a and a second circular part 56b of small radius. In the first part 56a of the outward track 56, the stroke carried out by the operating handle of the switching device 1 generates a proportional displacement of the moving element 40 and therefore of the moving contacts 36. In the second part 56b and at from the point of equilibrium between the parts 56a and 56b, the stroke carried out by the operating handle causes rapid displacement and bringing together of the mobile assembly 40 having the effect of very rapid positioning and tightening of the mobile contacts 36 on the corresponding fixed contacts 33, 33 '. The outward track 56 has a variable depth, increasing in the direction of rotation, then an abrupt change in level caused by a shoulder 56c. Thus, at the end of rotation, the cam 50 moves axially by a value equal to the difference in depth, by relaxing the return spring 52. This 12

axial movement of the cam 50 has the advantage of positioning the drive finger 45 immediately in the return track 57.

When triggering, that is to say to pass from the engaged position (cf. Fig. 4 and 5) to the triggered position (cf. Fig. 2 and 3), an attempt is made to achieve the most abrupt separation between the moving contacts and the fixed contacts. The return track 57 therefore comprises two parts (see for clarity in FIG. 4 in which the parts are hatched): a first circular part 57a of constant radius centered on the axis A and a second circular part 57b of which the radius is much smaller than said constant radius. In the first part 57a of the return track 57, the stroke carried out by the operating handle of the switching device 1 has no effect on the movement of the moving element 40 and therefore on that of the moving contacts 36. Nevertheless, the energy is stored in the snap action device 24. In the second part 57b and from the point of equilibrium between the two parts 57a and 57b, the stroke made by the operating handle results, in combination with the action device abrupt 24, rapid movement and removal of the moving element 40 and therefore of the moving contacts 36 having the effect of an abrupt cut. The return track 57 has a variable depth which decreases in the direction of rotation. Thus, during this rotation, the cam 50 moves axially by a value equal to the difference in depth, by compressing the return spring 52. This axial movement of the cam 50 has the advantage of positioning the drive finger 45 immediately at the starting point, in the runway 56.

The outward and return tracks 56 have different shapes so as to ensure safe guiding of the drive finger 45 in the correct track so that it is guided, during engagement, by the internal wall 55a of the groove and , when triggered, by the external wall 55b. Furthermore, to avoid excessive forces on the drive fingers 45 of the moving parts 40, the axial displacement of the cams 50 induced by the relief of the outward and return tracks, is helped by the adapted cam profile 53 provided on the barrel. 51. This cam profile 53 rests on the lugs 54 integral with the housing 4 and the cover of the device 1 and helps the cams 50, in association with the spring 52, to move axially during their rotation. 13

The outward and reverse tracks 56 and 57 can have other curvatures and rehefs so as to optimize the switching on and off conditions for each switching device 1.

This switching device 1 also includes a test position illustrated in FIGS. 6 to 8. This test position makes it possible to actuate auxiliary contacts arranged for example on the control module 2 to test their control circuits making it possible to check the engaged state. or triggered by the switching device. This test position is obtained by turning the handle of the device by an angle of 60 to 90 ° in the opposite direction to that of the engagement. At the time of this rotation, the moving parts 40 must not move, the switching device 1 having to remain in the tripped position. Each groove 55 is extended by a test track 58, framed by the internal 55a and external 55b walls, this track being circular, close to the control axis 23, of constant radius and of center the axis A and ending in a imprint 59 corresponding to the end of the drive finger 45 in the test position.

On the rear face of the cam 50 is provided a circular groove 60 close to the control axis 23 and centered on the axis A. This circular groove 60 is intended to receive the guide shoe 46 provided on the moving parts 40 in look of the drive finger 45. It ensures the guiding of the moving parts 40 relative to the cams 50 so that, when the test phase is complete, the drive finger 45 is repositioned in the right track, namely the runway 46.

In FIG. 8, it can be seen that the cam 50 has a peripheral zone of reduced thickness 61, the function of which is twofold. First of all, it allows the mounting of the cam 50 in the frame 41 of the movable assembly 40, between the drive finger

45 and the guide shoe 46. It then allows automatic locking of the cover (not shown) of the switching device 1 when the latter is in the engaged position, by means of an additional device provided on said cover.

From the following description, it will be noted that the invention achieves all the aims mentioned. In conclusion, it makes it possible to significantly lower the manufacturing cost of the cut-off modules and therefore of the cut-off device while improving its technical performance. In addition, apart from the conductive parts which are made for example of copper, almost all of the parts of the mechanism 14

for driving the movable contacts can be produced by molding in a technically suitable material, such as thermoplastic or thermoset.

The present invention is not limited to the example of reahsation described but extends to any modification and variant obvious to a person skilled in the art. Of course, the number of breaking modules depends on the number of phases of the installation with the presence or not of a neutral. Therefore, the number of fixed contacts, mobile contacts, cams, windows and notches provided in the context of mobile equipment is adapted accordingly. Similarly, the shape of the different parts making up said mechanism for controlling the movable contacts can vary while remaining within the protective field defined in the claims. In particular, the geometry of the outward, return and test tracks illustrated and described is given only by way of example.

Claims

15 Claims

1. Electrical cut-off device (1) for low-voltage AC electrical installation provided with at least two phase conductors with or without neutral conductor, comprising a cut-off module (3) per conductor and a control module (2) common provided with a mechanism for actuating said cut-off modules, each cut-off module comprising at least one input terminal (30) connected to a fixed contact (31), one output terminal (32) connected to a fixed contact (33), two other fixed contacts (31 ', 33') re-connected together by a bridge or a fuse and forming with the other fixed contacts two pairs of fixed contacts and two movable contacts (35, 36) associated respectively with a pair of fixed contacts, the control module (2) comprising at least one control axis (23) coupled to an operating handle, this axis passing through said cut-off modules (3) and carrying at least one cam (50) coupled to at least one crew (40) movable in translation and coupled to said movable contacts (35, 36) for moving them from a first stable position called the engaged position to a second stable position called the tripped position, characterized in that each movable contact (35, 36) has two contact surfaces (38) arranged in substantially perpendicular planes, in that the fixed contacts (31, 31 'and 33, 33') of the same pair are arranged in substantially perpendicular planes so that their respective contact surfaces (37) are placed opposite the corresponding contact surfaces (38) provided on said movable contact (35, 36) when it is in the engaged position and in that each movable contact (35, 36) moves in radial translation relative to the axis of control (23) in a direction (F) substantially perpendicular to a straight line passing through its two contact surfaces (38).

2. Apparatus according to claim 1, characterized in that each movable contact (35, 36) comprises two end branches arranged on either side of a middle branch and forming an angle of approximately 45 ° relative to said middle branch, the contact surfaces (38) being provided on the two end branches.

3. Apparatus according to claim 1, characterized in that the movable assembly (40) consists of a frame (41) substantially rectangular extending through said modules of the cutoff (3) and arranged in an inclined plane parallel to the control shaft (23). 16

4. Apparatus according to claim 3, characterized in that the frame (41) has at least two parallel walls (47), oriented radially with respect to the control axis (23) and arranged to slide along two walls ( 48) corresponding formed in the housing (4) of said apparatus for guiding said frame

(41) in translation.

5. Apparatus according to claims 2 and 3, characterized in that the frame (41) comprises, for each movable contact (35, 36) corresponding, a window (42) oriented substantially perpendicular to the control axis (23) and a return spring (43) housed in this window (42) to solicit said movable contact (35, 36) in the direction of the fixed contacts (31, 31 'and 33, 33').

6. Apparatus according to claim 3, characterized in that the frame (41) comprises at least one notch (44) intended to receive said cam (50), at least one wall of this notch comprising a drive finger (45) substantially parallel to the control axis (23) and engaged in at least one track (56, 57) provided in said cam (50).

7. Apparatus according to claim 6, characterized in that the cam (50) comprises, for each movable assembly (40), a groove (55) non-circular, delimited by an internal wall (55a) close to the control axis (23) and an outer wall (55b) remote from the control axis (23), these walls being arranged to guide said drive finger (45), respectively on engagement and release.

8. Apparatus according to claim 7, characterized in that the bottom of the groove (55) comprises different rehefs arranged to define, respectively with the internal walls (55a) and external (55b), two separate tracks (56, 57) either a forward track (56) for switching on and a return track (57) for triggering.

9. Apparatus according to claim 8, characterized in that the outward track (56) comprises a first part (56a) substantially rectilinear and a second part (56b) circular of small radius eccentric relative to the control axis (23) and the return track (57) comprises a first circular portion (57a) of constant radius centered on 17

the control axis (23) and a second circular part (57b) whose radius is less than said constant radius.

10. Apparatus according to claim 9, characterized in that the second part (56b) of the outward track (56) communicates with the first part (57a) of the return track (57) by a shoulder (56c).

11. Apparatus according to claims 1 and 8, characterized in that the cam (50) comprises a central shaft (51) rotating in rotation of the control shaft (23) and sliding thereon and in that the notch (44) provided in the frame (41) of the movable assembly (40) has a width greater than that of the cam (50) allowing it an axial clearance (D) corresponding to the relief differences in the bottom of the groove (55 ).

12. Apparatus according to claim 11, characterized in that the barrel (51) has at least one of its free ends a cam profile (53) cooperating with at least one lug (54) provided at least in the housing (4 ) of said device and oriented radially with respect to the control axis (23) and in that the control axis (23) carries a return spring (52) arranged to hold the cam profile (53) in contact with said lug (54).

13. Apparatus according to claim 8, characterized in that the groove (55) is extended, in a direction opposite to that of the outward tracks (56) and return (57), by a test track (58), framed by the walls internal (55a) and external (55b), this track (58) being circular, close to the control axis (23), of constant radius centered on this axis.

14. Apparatus according to claim 13, characterized in that the cam (50) has on its rear face a groove (60) circular near the control axis (23) centered on this axis and in that the frame (41 ) of the movable assembly (40) comprises a guide shoe (46) disposed opposite the drive finger (45) and arranged to be housed in said groove (60) when the device is in the test position.