Switching device with keying means

Abstract

A switching device comprising movable contacts carried by a first end of at least two contact arms mounted around a pivot (21) to permit pivoting of said contact arm towards a closing position of said contacts, said device comprising contact pressure means comprising two torsion springs (31, 32) acting on each of said contact arms, each torsion spring comprising 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 closing position.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates in particular to an insulating housing switching device 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 a pivoting of said contact arm towards a closing 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.

[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, neutral circuit breaker comprising two movable contacts, one for a phase circuit and one for a neutral circuit. These contacts are carried by contact arms made of insulating material, pivotally mounted about an axis supported by a plate-shaped control mechanism. This support is itself pivotally mounted on a fixed axis. A spiral contact pressure spring is mounted around the pivot axis of the contact arms, allowing them to be forced into the closed position of the movable contacts.

[0004] One drawback of the circuit breaker described in patent application EP0042778 is that the sizing and arrangement of the contact pressure spring are not optimized.

[0005] One drawback of the device described in French patent application no. 10 00821 is that care must be taken when positioning the torsion springs during assembly. Incorrect positioning of a torsion spring can reduce the contact pressure force, resulting in excessively high impedance contact.

[0006] Furthermore, patent application FR 2 956 922 A1 describes an insulating housing switching device 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 permit a pivoting of said contact arm towards a closing 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. DESCRIPTION OF THE INVENTION

[0007] The invention aims to remedy the drawbacks of prior art switching devices by proposing a switching device with an insulating housing 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 a pivoting of said contact arm towards a closing 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 said contact arm carrying the movable phase contact and said contact arm carrying the movable neutral contact respectively,each torsion spring exerting a torsional force about an axis of rotation of said spring, each torsional spring being arranged relative to the contact arm on which it acts such 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 torsional 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 cutting device being characterized in that each contact arm includes a means of error correction 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 torsional force exerted on the contact arm is insufficient to move the contact arm into its closed position.

[0008] According to one embodiment of the invention, the error-proofing 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.

[0009] According to one embodiment of the invention, the support lever includes a positioning stop.

[0010] Preferably, the device includes 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 disposed between the contact arm on which said torsion spring acts and said support lever.

[0011] Preferably, the support lever is articulated around an axis coinciding with the axis of the pivot.

[0012] In one embodiment, each torsion spring comprises a first strand (35, 36) bearing against a stop on 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 on the contact arm on which the torsion spring acts, said stop being offset from the pivot towards the second end of said contact arm. Preferably, the stop on the contact arm is provided on the second end of said contact arm.

[0013] In one embodiment, the first strand of each contact spring is longer than the second strand of said contact spring. Preferably, the length of the first strand is at least twice the length of the second strand.

[0014] According to one embodiment, the first strands of the torsion springs are connected to form an elastic assembly comprising said two torsion springs.

[0015] Preferably, the control mechanism also includes: a pivotally mounted handle on the insulating housing to control the opening and closing of the moving contacts, transmission means arranged between said handle and the contact arms including a breakable mechanical link, and a release lever coupled to release means to detect the presence of an electrical fault, said release lever being designed to actuate the movement of the contact arms into the open position by causing a breakage of said breakable mechanical link. BRIEF DESCRIPTION OF THE FIGURES

[0016] Other advantages and features will become clearer from the following description of particular embodiments of the invention, given by way of non-limiting examples, and represented in the attached figures. There figure 1 is a view inside a circuit breaker according to the invention, representing most of the elements of the control mechanism. figure 2 This is a partial view of the control mechanism, in which one of the contact arms has been removed to allow visualization of the support lever and the contact pressure means. figure 3 This is a view of the control mechanism, showing most of the elements of the kinematic chain between the operating handle and the moving contacts. figure 4 corresponds to the figure 3 in which one of the contact arms was removed to allow visualization of the contact pressure means. figure 5is an exploded view of the contact arms, the support lever, and the contact pressure means. figure 6 is an exploded view of the control and triggering mechanisms. figure 7 is a view of the support lever illustrating a second strand correctly positioned and a second strand incorrectly positioned. figure 8 includes a partial view of a contact arm of a phase-cutting circuit according to the prior art and a partial view of a contact arm of a phase-cutting circuit according to the invention. figure 9 includes a partial view of a contact arm of a neutral disconnect circuit according to the prior art and a partial view of a contact arm of a neutral disconnect circuit according to the invention. Figure 10 illustrates a partial view of a device according to the invention when a second strand is incorrectly positioned. figure 11 is a detail of the Figure 10 showing the second strand is incorrectly positioned. DETAILED DESCRIPTION OF A METHOD OF IMPLEMENTATION

[0017] As can be seen on the figure 1 The circuit breaker 1 comprises an insulating housing 3 essentially formed by two half-shells, the upper half-shell having been removed to allow visualization of the interior of the circuit breaker. The housing 3 has a generally parallelepiped shape corresponding to a modular system. The housing 3 has a rear face 5 for mounting on a rail and a front face 7 with an opening for a control handle 9. The circuit breaker 1 includes a neutral breaking circuit and a phase breaking circuit arranged respectively on either side of an insulating partition 11 interposed between the two half-shells and extending parallel to the main faces of the housing 3. On the figure 1 , only the phase switching circuit is visible, the neutral switching circuit being located behind the insulating partition 11.

[0018] The phase-cutting circuit includes a movable phase contact 13 carried by a first end of a contact arm 15. Similarly, the neutral-cutting circuit includes 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.

[0019] The circuit breaker 1 has a control mechanism housed in the upper part of the casing 3, above the insulating partition 11. This control mechanism is common to the phase moving contact 13 and the neutral moving contact 17. The pivot 21 for articulating the contact arms 15, 19 is supported by a support lever 23 ( figure 5) in the form of a plate, often called a mounting plate, the support lever being pivotally mounted on the housing. In this case, the support lever 23 is pivotally mounted about an axis parallel to and coinciding with the axis of the pivot 21 of the contact arms 15, 19. The pivot axis of the support lever 23 and the pivot of the contact arms 15, 19 are formed by a shaft 21 integral with the support lever 23. The ends of the shaft 21 are mounted in bearings formed in the half-shells of the housing 3. The contact arms 15, 19 also have bearings allowing the contact arms 15, 19 to be fitted onto the shaft 21 on either side of the support lever 23.

[0020] The pivoting mounting of the support lever 23 on the housing 3 allows the contact arms 15, 19 to move between an open position of the moving contacts 13, 17 and a closed position of said moving contacts. The support lever 23 has stops that cooperate with the contact arms 15, 19 to rotate them around the shaft 21 towards the closed position of the moving contacts 13, 17. A spring 90 mounted between the housing and the support lever 23 causes the support lever 23 to rotate around the shaft 21 towards the open position of the moving contacts 13, 17.

[0021] 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 closing position of the moving contacts 13, 17.

[0022] Each of the contact arms 15, 19 includes a screen 26 that prevents particles generated by the electric arc from entering the control mechanism. The screen 26 is arranged to slide along a fixed wall 61 to ensure its screening function during at least the initial opening of the contacts. The faces of the screen 26 and the opposite fixed wall 27 are positioned sufficiently close to each other to allow the fixed wall to scrape the face of the screen exposed to the electric arc, thus preventing any buildup of deposits.

[0023] The control mechanism includes contact pressure means acting on the contact arms 15, 19 to exert a pressure force on said contact arms and to constrain said contact arms to 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 phase movable contact 13 and on the contact arm 19 carrying the neutral movable contact 17. Each torsion spring 31, 32 is provided with an axis of rotation around which it exerts a torsional force. The torsion springs 31, 32 are mounted such 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 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 multiplies 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 reduces their dimensions.

[0024] More specifically, each torsion spring 31, 32 is positioned between the contact arm 15, 19, on which the torsion spring acts, and the support lever 23. In this way, the torsion springs 31, 32 are sized to exert a closing pressure on the movable contacts 13, 17, allowing limited pivoting of the contact arms 15, 19 relative to the support lever, depending on the wear of said contacts. The torsion springs 31, 32 are not sized to pivot the contact arms 15, 19 from the open to the closed position of the contacts 13, 17; this function is performed by the support lever 23. The sizing of the torsion springs 31, 32 is therefore determined solely by the contact pressure force to be exerted, and the dimensions of said springs are consequently reduced.

[0025] As can be seen on the figures 2 And 4The torsion springs 31, 32 used are coil springs. Each torsion spring 31, 32 has 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, which forms the pivot of the contact arm 15, 19, towards the second end of said contact arm opposite the first end carrying the movable contacts 13, 17. In this case, the stop 45, 46 of the contact arm 15, 19 is located at the second end of said contact arm. Thus, the contact pressure exerted by the torsion springs 31, 32 is maximized.

[0026] The coils 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 overall size of the control mechanism at the shaft 21 is reduced. Given the complexity of the control mechanism with regard to the joints around the shaft 21, this offset of the coils of the torsion springs 31, 32 relative to the shaft 21 simplifies the control mechanism and facilitates its assembly.

[0027] In the embodiment shown, the first strands 35, 36 of the torsion springs 31, 32 are connected together to form a single elastic assembly incorporating said torsion springs. As can be seen in the figures 2 And 4The first strand 35, 36 of each torsion spring 31, 32 is longer than the second strand 41, 42 of said torsion spring. More precisely, the length of the first strand 35, 36 is at least twice the length of the second strand 41, 42. This arrangement facilitates the assembly of the control mechanism, particularly because the length of the strands allows for the necessary flexing for mounting on the spring shafts.

[0028] The circuit breaker control mechanism may be such as that described in European patent application EP0295158.

[0029] In the embodiment shown, the control mechanism includes transmission means arranged between the handle 9 and the contact arms 15, 19, or more precisely between said handle and the support lever 23. These transmission means allow the support lever 23 to be moved between the open position and the closed position of the movable contacts 13, 17.

[0030] As can be seen on the figure 6A trip lever 53 coupled to tripping means allows the presence of an electrical fault to be detected and the control mechanism to be activated to open the circuit breaker contacts. 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 from 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 linkage 61 of the transmission means ( Figures 1 And 2 ).

[0031] The transmission means include a linkage 51 coupled to an internal base of the control lever to form a toggle joint whose articulation is offset relative to a pivot axis 63 of said control lever. The breakable mechanical linkage 61 is provided between the linkage 51 and the support lever 23. In the locked position, the breakable mechanical linkage 61 allows manual control of the control mechanism using the control lever 9. Movement of the trigger lever 53 to a triggered position under the action of the trigger 55 causes the momentary breakage of the mechanical linkage 61, resulting in the automatic triggering of the control mechanism, independently of the control lever 9.The trigger lever 53 is associated with a return spring (not shown) intended to ensure the automatic restoration of the mechanical link 61 when the handle 9 is actuated towards the open position, following a triggering of the control mechanism on fault.

[0032] As can be seen on the figure 6The breakable mechanical linkage 61 includes a hook 65 pivotally mounted on an axis 67 of the support lever 23. Opposite the axis 67, the hook's beak 69 cooperates, in the locked position of the linkage 61, with a retaining notch 71 located on the upper arm of the release lever 53. The transmission link 51 is coupled to the hook 65 at a pivot point that can move during release within a slot in the support lever 23. This slot is either blind or open and is shaped as a circular sector centered on the axis 67. The pivot point is located between the axis 67 and the hook's beak 69. The breakable mechanical linkage 61 constitutes a reduction stage in the kinematic chain of the control mechanism, allowing a reduction in the release force from the thermal-magnetic release.

[0033] As can be seen on the figures 2 And 6The bimetallic strip 57 of the thermal trip unit cooperates with the trip lever 53 by means of a rotary spool 81 with unidirectional transmission. The spool 81 is formed by a bent lever having one end freely coupled to the lower arm of the trip lever 53 at a pivot point 83. The curved intermediate portion of the transmission lever bears against a boss 85 of the trip lever 53 so as to drive the latter to the tripped position when the bimetallic strip 57 deflects to the right in the event of an overload current flowing through the pole. During this thermal tripping phase, the spool 81 constitutes a rigid kinematic link between the bimetallic strip 57 and the trip lever 53. The pivot point 83 is located 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.

[0034] When the control mechanism is manually or automatically actuated to the open position, the end 87 of the drawer 81 opposite the pivot point 83 is liable to come into contact with a protrusion of the housing, breaking the kinematic link with the trigger lever 53. The support lever 23 can pivot around the pivot 21 in a counterclockwise direction, and the intermediate area of ​​the drawer 81 is separated from the boss 85. The pivot point 83 of the drawer 81 could, of course, coincide with the pivot axis 21 of the trigger lever 53.

[0035] The operation of such a control mechanism is well known to specialists, and it is unnecessary to describe it in further detail. This operation is also described in patent application EP0295158.

[0036] As can be seen on the figure 5 During the assembly of device 1, the torsion springs 31, 32 are first placed on the support lever 23. The support lever 23 includes a positioning stop 100 for assembly. Each second strand 41, 42 is placed against the positioning stop 100, which is adapted to facilitate the assembly of the support lever 23 with the contact arms 15, 19. The second strand 41, or the second strand 42 respectively, is placed against the stop 100 on the support lever 23, allowing its correct positioning against the stop 45, or the stop 46 respectively, during assembly with the contact arm 15, or the contact arm 19 respectively.

[0037] There figure 7is a view of the support lever 23 illustrating a second strand 41 correctly positioned and a second strand 42 incorrectly positioned. figure 7 illustrates the support lever 23 of the figure 5 seen from another angle and allows visualization of the stop 100 against which the two strands 41 and 42 are normally pressed as illustrated in the figure 5 In the figure 7 Strand 41 is in its correct position, resting on stop 100. However, strand 42 is incorrectly positioned, having passed behind stop 100.

[0038] There figure 8includes a partial view of a contact arm 15 of a phase-cutting circuit according to the prior art and a partial view of a contact arm 15' of a phase-cutting 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 includes a stop 45' similar to the stop 45 of the contact arm 15.

[0039] The error-correction 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 torsional force exerted on the contact arm 15' is insufficient to move the contact arm 15' into its closed position. This is advantageous compared to a contact arm 15 without an error-correction means because it avoids obtaining a closed position with a high-impedance contact due to insufficient pressure. This would necessitate complicated tests to detect such a situation. The error-correction 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 containing a misaligned torsion spring, thus reducing the time spent on the functional testing of each device.

[0040] There figure 9 includes a partial view of a contact arm 19 of a neutral disconnect circuit according to the prior art and a partial view of a contact arm 19' of a neutral disconnect 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 includes a stop 46' similar to the stop 46 of the contact arm 19.

[0041] The error-correction 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 torsional force exerted on the contact arm 19' is insufficient to move the contact arm 19' into its closed position. The error-correction means 120 has the same function as the error-correction means 110 described previously.

[0042] The error-proofing means 110, 120 can 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.

[0043] Without the presence of the recesses 110, 120, a strand 41, 42, if incorrectly positioned against the stop 100, would come into contact with the corresponding part of the contact arm, allowing the torsion spring to maintain a certain torsional force, sufficient to reach the closed position, but insufficient to allow low-impedance contact in the closed position. Functional testing of such a device is therefore complicated. The presence of the recess makes functional testing quick and easy, as even high-impedance contact can no longer be made in the closed position if a strand 41, 42 is incorrectly positioned.

[0044] There Figure 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 the Figure 10 that, although the device is shown in the closed position, no contact is made. Part A of the Figure 10 is illustrated in the figure 11 .

[0045] There figure 11 corresponds to detail A of the Figure 10 , showing the second strand 41 incorrectly positioned and protruding through the recess 110 of the contact arm 15', which effectively prevents said strand 41 from bearing weight, thus preventing the corresponding torsion spring 31 from exerting a force on the contact arm 15'. As illustrated in part B of the Figure 10 The 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

1. Breaking device (1) with an insulating housing (3), comprising 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 about a pivot (21) 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 (31, 32) independently acting on said contact arm carrying the movable phase contact and said contact arm carrying the movable neutral contact, respectively, each torsion spring exerting a torsional force about an axis of rotation of said spring, each torsion spring being arranged with respect to the contact arm on which it acts in such a way that the axis of rotation of said spring is offset towards a second end of said contact arm with respect to the axis of said pivot, and said device comprising a control mechanism provided with a support lever (23) carrying the pivot (21) about 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 located 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 stopper (39) of the support lever (23) and a second strand (41, 42) acting on one of the contact arms (15', 19'), • the breaking device (1) being characterized in that each contact arm (15', 19') comprises 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 torsional 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 comprise 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 either 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 about 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) interacts with a stop (45, 46) of the contact arm (15', 19') on which said torsion spring acts, said stop being offset with respect 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 formed 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 that is 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 furthermore comprises: • a handle (9) that is mounted on the insulating housing (3) so as to be able to pivot, in order to control the opening and closing of the movable contacts (13, 17), • transmission means arranged between said handle and the contact arms (15, 19) including a breakable mechanical connection (61), and • a tripping lever (53) coupled to tripping means (55, 57) to detect the presence of an electrical fault, said tripping lever being designed to prompt the contact arms (15', 19') to move into the open position by causing said breakable mechanical connection to break.

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