SWITCH-OFF DEVICE WITH KEYING MEANS

Abstract

CUTTING DEVICE A cutting device comprising movable contacts carried on a first end of at least two contact arms mounted around a pivot (21) to allow pivoting of said contact arm towards a closed position of said contacts, said device comprising contact pressure means having two torsion springs (31, 32) acting on each of said contact arms, each torsion spring having a second strand (41, 42), each contact arm (15', 19') comprising a keying means adapted so that, when the second strand (41', 42') is incorrectly positioned, then a torsional force exerted on the contact arm (15', 19') is insufficient to move the contact arm (15', 19') into its closed position. (Figure 2)

Description

Title of the invention: cutting device with foolproofing means TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates in particular to a switching device with an insulating casing containing movable contacts, including at least one movable phase contact and one movable neutral contact carried by a first end of at least two contact arms respectively, each contact arm being mounted around a pivot to at least allow pivoting of said contact arm towards a position for closing said contacts, said device comprising contact pressure means acting on said contact arms to exert a contact pressure force on said contact arms.

[0002] The invention relates more specifically to an improvement of the device described in French patent application No. 10 00821 filed on March 1, 2010 and published under publication number 2,956,922. STATE OF THE ART

[0003] Patent application EP0042778 describes a single-pole and neutral circuit breaker comprising two movable contacts of respectively a phase circuit and a neutral circuit, said contacts being carried by contact arms made of insulating material pivotally mounted around an axis carried by a plate-shaped support of an operating mechanism, said support being pivotally mounted on a fixed axis. A spiral contact pressure spring is mounted around the pivot axis of the contact arms and makes it possible to urge said contact arms into the closing position of the movable contacts.

[0004] A disadvantage of the circuit breaker described in patent application EP0042778 is that the dimensioning and arrangement of the contact pressure spring are not optimized.

[0005] A disadvantage of the device described in French patent application No. 10 00821 is that care must be taken when placing torsion springs during assembly of the device. Incorrect positioning of a torsion spring can reduce the contact pressure force, thus ensuring a contact of too high impedance. Statement of the invention

[0006] The invention aims to remedy the drawbacks of the cut-off devices of the prior art by proposing a cut-off device with an insulating housing containing movable contacts, including at least one movable phase contact and one movable contact neutral carried by a first end of respectively at least two contact arms, each contact arm being mounted around a pivot to at least allow pivoting of said contact arm towards a closed position of said contacts, said device comprising contact pressure means acting on said contact arms to exert a contact pressure force on said contact arms, the contact pressure means comprising two torsion springs acting independently on respectively said contact arm carrying the movable phase contact and said contact arm carrying the movable neutral contact, each torsion spring exerting a torsion force around an axis of rotation of said spring, each torsion spring being arranged relative to the contact arm on which it acts so that the axis of rotation of said spring is offset towards a second end of said contact arm, relative to the axis of said pivot,each torsion spring comprising a first strand bearing against a stop of the support lever and a second strand acting on one of the contact arms, the cut-off device being characterized in that each contact arm comprises a keying means adapted so that, when the second strand, acting on the contact arm to exert a contact pressure force on said contact arm, is incorrectly positioned, then a torsion force exerted on the contact arm is insufficient to move the contact arm into its closed position.

[0007] According to one embodiment of the invention, the keying means comprises a recess located at the end of the contact arm, the recess being adapted to receive the end of the second strand when the second strand is incorrectly positioned.

[0008] According to one embodiment of the invention, the support lever comprises a positioning stop.

[0009] Preferably, the device comprises a control mechanism provided with a support lever carrying the pivot around which the contact arms are mounted, said support lever being articulated to move the contact arms between an open position and the closed position of said movable contacts, each torsion spring being arranged between the contact arm on which said torsion spring acts and said support lever.

[0010] Preferably, the support lever is articulated around an axis which coincides with the axis of the pivot.

[0011] According to one embodiment, each torsion spring comprises a first strand (35, 36) bearing against a stop of the support lever and a second strand acting on one of the contact arms. Preferably, the second strand of each torsion spring cooperates with a stop of the contact arm on which said torsion spring acts, said stop being offset relative to the pivot towards the second end of said contact arm. Preferably, the stop of the contact arm is provided on the second end of said contact arm.

[0012] According to one embodiment, the first strand of each contact spring has a length greater than the length of the second strand of said contact spring. Preferably, the length of the first strand is greater than at least twice the length of the second strand.

[0013] According to one embodiment, the first strands of the torsion springs are connected to form an elastic assembly comprising said two torsion springs.

[0014] Preferably, the control mechanism further comprises: - a lever pivotally mounted on the insulating box to control the opening and closing of the moving contacts, - transmission means arranged between said lever and the contact arms including a breakable mechanical connection, and - a trigger lever coupled to trigger means for detecting the presence of an electrical fault, said trigger lever being designed to actuate the movement of the contact arms into the open position by causing a break in said breakable mechanical connection. BRIEF DESCRIPTION OF THE FIGURES

[0015] Other advantages and characteristics will emerge more clearly from the following description of particular embodiments of the invention, given as non-limiting examples, and represented in the appended figures.

[0016] [Fig.l] is a view inside a circuit breaker according to the invention showing most of the elements of the control mechanism.

[0017] [Fig. 2] is a partial view of the control mechanism, in which one of the contact arms has been dismantled to allow the support lever and the contact pressure means to be viewed.

[0018] [Fig. 3] is a view of the control mechanism, in which most of the elements of the kinematic chain between the operating handle and the moving contacts are represented.

[0019] [Fig.4] corresponds to [Fig.3], in which one of the contact arms has been dismantled to allow the contact pressure means to be viewed.

[0020] [Fig.5] is an exploded view of the contact arms, the support lever and the contact pressure means.

[0021] [Fig.6] is an exploded view of the control mechanism and the trigger mechanism.

[0022] [Fig.7] is a view of the support lever illustrating a correctly positioned second strand and a poorly positioned second strand.

[0023] [Fig.8] comprises a partial view of a contact arm of a phase cut-off circuit according to the prior art and a partial view of a contact arm of a phase cut-off circuit according to the invention.

[0024] [Fig.9] comprises a partial view of a contact arm of a breaking circuit neutral according to the prior art and a partial view of a neutral cut-off circuit contact arm according to the invention.

[0025] [Fig. 10] illustrates a partial view of a device according to the invention when a second strand is incorrectly positioned.

[0026] [Fig. 11] is a detail of [Fig. 10], showing the second strand incorrectly positioned. DETAILED DESCRIPTION OF AN EMBODIMENT

[0027] As can be seen in [Fig.l], the circuit breaker 1 comprises an insulating casing 3 essentially formed by two half-shells, the upper half-shell having been removed to allow the interior of said circuit breaker to be viewed. The casing 3 has a generally parallelepiped shape corresponding to a modular system. The casing 3 has a rear face 5 for fixing to a rail and a front face 7 having a passage opening for a control handle 9. The circuit breaker 1 comprises a neutral cut-off circuit and a phase cut-off circuit arranged respectively on either side of an insulating partition 11 inserted between the two half-shells and extending parallel to the main faces of the casing 3. In [Fig.l], only the phase cut-off circuit is visible, the neutral cut-off circuit being arranged behind the insulating partition 11.

[0028] The phase cut-off circuit comprises a movable phase contact 13 carried by a first end of a contact arm 15. In the same way, the neutral cut-off circuit comprises a movable neutral contact 17 carried by a first end of another contact arm 19. The contact arms 15, 19 are made of an insulating material and are pivotally mounted on a pivot 21.

[0029] The circuit breaker 1 comprises an operating mechanism housed in the upper part of the housing 3, above the insulating partition 11. This operating mechanism is common to the moving phase contact 13 and to the moving neutral contact 17. The pivot 21 for articulating the contact arms 15, 19 is carried by a support lever 23 ([Fig.5]) in the form of a plate, often called a plate, said support lever being pivotally mounted on the housing. In this case, the support lever 23 is pivotally mounted around an axis parallel to and coincident with the axis of the pivot 21 for articulating the contact arms 15, 19. The pivot axis of the support lever 23 and the pivot for articulating the contact arms 15, 19 are embodied by a shaft 21 secured to said support lever 23. The ends of the shaft 21 are mounted in bearings provided in the half-shells of the housing 3.The contact arms 15, 19 also comprise bearings allowing said contact arms 15, 19 to be fitted onto the shaft 21 respectively. on either side of the support lever 23.

[0030] The pivoting mounting of the support lever 23 on the housing 3 allows the movement of the contact arms 15, 19 between an open position of the movable contacts 13, 17 and a closed position of said movable contacts. The support lever 23 carries stops capable of cooperating with the contact arms 15, 19 to drive them in rotation around the shaft 21 towards the closed position of the movable contacts 13, 17. A spring 90 mounted between the housing and the support lever 23 makes it possible to urge the support lever 23 in rotation around the shaft 21 towards the open position of the movable contacts 13, 17.

[0031] The pivoting mounting of the contact arms 15, 19 on the support lever 23 allows, for its part, a limited movement of said contact arms, in particular when the support lever 23 has been pivoted into the closed position of the movable contacts 13, 17.

[0032] Each of the contact arms 15, 19 comprises a screen 26 which prevents particles generated by the electric arc from entering the control mechanism. The screen 26 is arranged to slide along a fixed wall 61 in order to ensure the screen function during at least the start of the opening of the contacts. The faces of the screen 26 and the fixed wall 27 facing each other are arranged sufficiently close to each other to allow said fixed wall to scrape the face of said screen exposed to the electric arc, which prevents any accumulation of deposit.

[0033] The control mechanism comprises contact pressure means acting on the contact arms 15, 19 to exert a pressure force on said contact arms and to force said contact arms into the closed position of the movable contacts 13, 17. The contact pressure means comprise two torsion springs 31, 32 acting respectively on the contact arm 15 carrying the movable phase contact 13 and on the contact arm 19 carrying the movable neutral contact 17. Each torsion spring 31, 32 is provided with an axis of rotation about which it exerts a torsion force. The torsion springs 31, 32 are mounted so that their respective axes of rotation are offset relative to the shaft 21 towards a second end of the contact arms. This second end of the contact arms 15, 19 is in this case opposite relative to the first end of said arms carrying the movable contacts 13, 17.This positioning of the springs 31, 32 and their respective axes of rotation makes it possible to multiply the force exerted by said springs on the contact arms 15, 19 and therefore on the movable contacts 13, 17 carried by said contact arms. This positioning of the springs 31, 32, and in particular the positioning of their respective axes of rotation, also makes it possible to reduce their dimensions.

[0034] More specifically, each torsion spring 31, 32 is arranged between the contact arm 15, 19 on which said torsion spring acts and the support lever 23. In this way, the torsion springs 31, 32 are dimensioned to exert a closing pressure movable contacts 13, 17 allowing limited pivoting of the contact arms 15, 19 relative to the support lever, depending on the state of wear of said contacts. The torsion springs 31, 32 are not dimensioned to pivot the contact arms 15, 19 from the open position to the closed position of the contacts 13, 17, this function being fulfilled by the support lever 23. The dimensioning of the torsion springs 31, 32 is therefore carried out with respect only to the contact pressure force to be exerted, and the dimensions of said springs are therefore reduced.

[0035] As can be seen in Figures 2 and 4, the torsion springs 31, 32 used are coil springs. Each torsion spring 31, 32 comprises a first strand 35, 36 bearing against a stop 39 of the support lever and a second strand 41, 42 acting on one of said contact arms 15, 19. The second strand 41, 42 of each torsion spring 31, 32 cooperates with a stop 45, 46 of the contact arm 15, 19 on which said torsion spring acts. This stop 45, 46 is offset relative to the shaft 21, materializing the pivot of the contact arm 15, 19, towards the second end of said contact arm opposite relative to the first end carrying the movable contacts 13, 17. In this case, the stop 45, 46 of the contact arm 15, 19 is arranged on the second end of said contact arm. Thus, the contact pressure exerted by the torsion springs 31, 32 is maximized.

[0036] The turns of the torsion springs 31, 32 surrounding the axis of rotation of said springs are offset relative to the shaft 21. In this way, in addition to increasing the contact pressure force and reducing the dimensions of the contact pressure means 31, 32, the size of the control mechanism at the shaft 21 is reduced. Given the complexity of the control mechanism concerning the articulations around the shaft 21, this offset of the turns of the torsion springs 31, 32 relative to the shaft 21 makes it possible to simplify said control mechanism and to facilitate its assembly.

[0037] In the embodiment shown, the first strands 35, 36 of the torsion springs 31, 32 are connected together to form a single elastic assembly integrating said torsion springs. As can be seen in Figures 2 and 4, the first strand 35, 36 of each torsion spring 31, 32 has a length greater than the length of the second strand 41, 42 of said torsion spring. More precisely, the length of the first strand 35, 36 is greater than at least twice the length of the second strand 41, 42. This arrangement makes it possible in particular to facilitate the assembly of the control mechanism, in particular thanks to the length of the strands which allows the bending necessary for mounting on the axes of the springs.

[0038] The circuit breaker control mechanism may be such as that described in European patent application EP0295158.

[0039] In the embodiment shown, the control mechanism comprises transmission means arranged between the lever 9 and the contact arms 15, 19, or more precisely between said lever and the support lever 23. These transmission means make it possible to move the support lever 23 between the open position and the closed position of the movable contacts 13, 17.

[0040] As can be seen in [Fig. 6], a trip lever 53 coupled to tripping means makes it possible to detect the presence of an electrical fault and to act on the control mechanism to open the contacts of the circuit breaker. The tripping means include an electromagnetic trip 55 and a thermal trip, in this case a bimetallic strip 57. The trip lever 53 is pivotally mounted on an axis 59 carried by the support lever 23, with a predetermined offset relative to the pivot 21. The trip lever 53 is designed to actuate the movement of the contact arms 15, 19 into the open position by causing the rupture of a breakable mechanical connection 61 of the transmission means (Figures 1 and 2).

[0041] The transmission means include a transmission link 51 coupled to an internal base of the lever to form a knee joint whose articulation is eccentric relative to a pivot axis 63 of said lever. The breakable mechanical connection 61 is provided between the transmission link 51 and the support lever 23. In the locked position, the breakable mechanical connection 61 allows manual control of the control mechanism using the lever 9. The movement of the trigger lever 53 to a triggered position under the action of the trigger 55 causes the mechanical connection 61 to break momentarily, resulting in the automatic triggering of the control mechanism, independently of the lever 9.The trigger lever 53 is associated with a return spring (not shown) intended to ensure the automatic reestablishment of the mechanical connection 61 when the handle 9 is actuated towards the open position, following triggering of the control mechanism on fault.

[0042] As can be seen in [Fig. 6], the breakable mechanical connection 61 comprises a hook 65 pivotally mounted on an axis 67 of the support lever 23. Opposite the axis 67, the beak 69 of the hook cooperates in the locked position of the connection 61 with a retaining notch 71 located on the upper arm of the trigger lever 53. The transmission link 51 is coupled to the hook 65 at a point of articulation capable of moving during triggering in a slot in the support lever 23. This slot is blind or open, and is shaped as a circular sector centered on the axis 67. The point of articulation is located between the axis 67 and the beak 69 of the hook. The breakable mechanical connection 61 constitutes a reduction stage in the kinematic chain of the control mechanism, allowing a reduction in the triggering force from the magneto-thermal trigger.

[0043] As can be seen in Figures 2 and 6, the bimetallic strip 57 of the thermal trip device cooperates with the trip lever 53 by means of a rotary slide 81 with unidirectional transmission. The slide 81 is formed by a bent lever having one end freely coupled to the lower arm of the trip lever 53 at a hinge point 83. The curved intermediate part of the transmission lever bears on a boss 85 of the trip lever 53 so as to drive the latter towards the tripped position during the deflection to the right of the bimetallic strip 57 in the event of an overload current flowing in the pole. During this thermal trip phase, the slide 81 constitutes a rigid kinematic connection between the bimetallic strip 57 and the trip lever 53. The hinge point 83 is arranged between the boss 85 and the pivot axis 21 of the trip lever 53.The purpose of this arrangement of the pivot axis 83 as close as possible to the pivot axis 21 is to minimize the displacement of the axis 83 along an arc of a circle centered on the axis 21, or even to make it zero, when the magnetic trigger 55 propels the support lever 23.

[0044] When the control mechanism is actuated manually or automatically towards the open position, the end 87 of the drawer 81 opposite the articulation point 83 is likely to come into abutment against a protuberance of the housing, with rupture of the kinematic connection with the trigger lever 53. The support lever 23 can pivot around the pivot 21 in the trigometric direction, and the intermediate zone of the drawer 81 is spaced from the boss 85. The articulation point 83 of the drawer 81 could of course be confused with the pivot axis 21 of the trigger lever 53.

[0045] The operation of such a control mechanism is well known to specialists, and there is no need to describe it in more detail. This operation is also described in patent application EP0295158.

[0046] As can be seen in [Fig. 5], when assembling the device 1, the torsion springs 31, 32 are first placed on the support lever 23. The support lever 23 comprises a positioning stop 100 for assembly. Each second strand 41, 42 is placed in abutment against the positioning stop 100 adapted to facilitate the assembly of the support lever 23 with the contact arms 15, 19. The second strand 41, respectively the second strand 42, is placed in abutment against the stop 100 on the support lever 23, allowing its correct positioning against the stop 45, respectively the stop 46, when assembling with the contact arm 15, respectively the contact arm 19.

[0047] [Fig. 7] is a view of the support lever 23 illustrating a correctly positioned second strand 41 and a mispositioned second strand 42. [Fig. 7] illustrates the support lever 23 of [Fig. 5] seen from another angle and allows the stop 100 to be visualized against which the two strands 41 and 42 are normally pressed as illustrated in [Fig. 5]. In [Fig. 7], the strand 41 is in its correct position, pressing against the stop 100. On the other hand, the strand 42 is poorly positioned, having passed behind the stop 100.

[0048] [Fig. 8] comprises a partial view of a contact arm 15 of a phase cut-off circuit according to the prior art and a partial view of a contact arm 15' of a phase cut-off circuit according to the invention. The contact arm 15' according to the invention differs from the contact arm 15 by the presence of a keying means 110. The contact arm 15' thus comprises a stop 45' similar to the stop 45 of the contact arm 15.

[0049] The keying means 110 is adapted so that, when the second strand 41, acting on the contact arm 15' to exert a contact pressure force on said contact arm 15', is incorrectly positioned, then the torsion force exerted on the contact arm 15' is insufficient to move the contact arm 15' into its closed position. This is advantageous compared to the contact arm 15 not comprising a keying means because it avoids obtaining a closed position with a high impedance contact due to insufficient pressure. This requires setting up complicated tests to detect this situation. The keying means 110 ensures that in the event of incorrect positioning of the strand 41, the contact arm 15' cannot reach the closed position. It is then easy to detect a device comprising a poorly positioned torsion spring, thus reducing the time spent on the functional test of each device.

[0050] [Fig. 9] comprises a partial view of a contact arm 19 of a neutral cut-off circuit according to the prior art and a partial view of a contact arm 19' of a neutral cut-off circuit according to the invention. The contact arm 19' according to the invention differs from the contact arm 19 by the presence of a keying means 120. The contact arm 19' thus comprises a stop 46' similar to the stop 46 of the contact arm 19.

[0051] The keying means 120 is adapted so that, when the second strand 42, acting on the contact arm 19' to exert a contact pressure force on said contact arm 19', is incorrectly positioned, then the torsion force exerted on the contact arm 19' is insufficient to move the contact arm 19' into its closed position. The keying means 120 has the same function as the keying means 110 described previously.

[0052] The keying means 110, 120 may be a recess 110, 120, or hole, located at the end of the contact arm 15', 19', the recess being adapted to receive the end of the second strand when the second strand 15', 19' is incorrectly positioned.

[0053] Without the presence of the recesses 110, 120, a strand 41, 42 poorly positioned against the stop 100 would come into contact against the corresponding part of the contact arm and would allow the torsion spring to maintain a certain torsion force, sufficient to allow the closing position to be reached, but insufficient to allow a low impedance contact in the closed position. The functional test of such a device is therefore complicated to set up. The presence of the recess makes the functional test easy and quick to carry out, a contact, even of high impedance, can no longer be made in the closed position in the event of an incorrect position of a strand 41, 42.

[0054] [Fig. 10] illustrates a partial view of a device according to the invention when a second strand is incorrectly positioned. It is thus visible in part B of [Fig. 10] that, although the device is shown in the closed position, contact is not made. Part A of [Fig. 10] is illustrated in [Fig. 11].

[0055] [Fig. 11] corresponds to detail A of [Fig. 10], showing the second strand 41 incorrectly positioned and then protruding through the recess 110 of the contact arm 15', which in fact prevents said strand 41 from being supported, thus preventing the corresponding torsion spring 31 from exerting a force on the contact arm 15'. As illustrated in part B of [Fig. 10], contact in the closed position is not made due to insufficient force on the contact arm 15'. The operation of the invention is identical with the contact arm 19' thanks to the recess 120.

Claims

Claims

1. Cut-off device (1) with an insulating housing (3) containing movable contacts, including at least one movable phase contact (13) and one movable neutral contact (17) carried by a first end of respectively at least two contact arms (15', 19'), each contact arm being mounted around a pivot (21) to at least allow pivoting of said contact arm towards a position for closing said contacts, said device comprising contact pressure means acting on said contact arms to exert a contact pressure force on said contact arms, the contact pressure means comprising two torsion springs (31, 32) acting independently on respectively said contact arm carrying the movable phase contact and said contact arm carrying the movable neutral contact, each torsion spring exerting a torsion force around an axis of rotation of said spring,each torsion spring being arranged relative to the contact arm on which it acts so that the axis of rotation of said spring is offset towards a second end of said contact arm, relative to the axis of said pivot, and in that it comprises a control mechanism provided with a support lever (23) carrying the pivot (21) around which the contact arms are mounted, said support lever being articulated to move the contact arms between an open position and the closed position of said movable contacts, each torsion spring (31, 32) being arranged between the contact arm (15', 19') on which said torsion spring acts and said support lever, • each torsion spring (31, 32) comprising a first strand (35, 36) bearing against a stop (39) of the support lever (23) and a second strand (41, 42) acting on one of the contact arms (15', 19'), • the cutting device (1) being characterized in that each contact arm (15', 19') comprises a keying means adapted so that, when the second strand (41', 42'), acting on the contact arm (15', 19') to exert a contact pressure force on said contact arm (15', 19'), is incorrectly positioned, then a torsion force exerted on the contact arm (15', 19') is insufficient to move the contact arm (15', 19') into its closed position.

2. Device according to the preceding claim, characterized in that the keying means comprises a recess (110, 120) located at the end of the contact arm (15', 19'), the recess being adapted to receive the end of the second strand when the second strand (15', 19') is incorrectly positioned.

3. Device according to any one of the preceding claims, characterized in that the support lever (23) comprises a positioning stop (100).

4. Device according to any one of the preceding claims, characterized in that the support lever (23) is articulated around an axis coincident with the axis of the pivot (21).

5. Device according to any one of the preceding claims, characterized in that the second strand (41, 42) of each torsion spring (31, 32) cooperates with a stop (45, 46) of the contact arm (15', 19') on which said torsion spring acts, said stop being offset relative to the pivot (21) towards the second end of said contact arm.

6. Device according to the preceding claim, characterized in that the stop (45, 46) of the contact arm (15', 19') is provided on the second end of said contact arm.

7. Device according to any one of the preceding claims, characterized in that the first strand (35, 36) of each contact spring (31, 32) has a length greater than the length of the second strand (41, 42) of said contact spring.

8. Device according to the preceding claim, characterized in that the length of the first strand (35, 36) is greater than at least twice the length of the second strand (41, 42).

9. Device according to any one of the preceding claims, characterized in that the first strands (35, 36) of the torsion springs (31, 32) are connected to form an elastic assembly comprising said two torsion springs.

10. Device according to any one of the preceding claims, characterized in that the control mechanism further comprises: • a lever (9) pivotally mounted on the insulating housing (3) to control the opening and closing of the movable contacts (13, 17), • transmission means arranged between said lever and the contact arms (15, 19) including a mechanical connection breakable (61), and a trigger lever (53) coupled to trigger means (55, 57) for detecting the presence of an electrical fault, said trigger lever being adapted to actuate the movement of the contact arms (15', 19') into the open position by causing a break in said breakable mechanical connection.

Images