EP0393566B1 - Circuit breaker - Google Patents

Description

The present invention relates to an electric circuit breaker comprising a fixed contact and a movable contact linked to a pivoting support articulated around a first axis secured to a housing, a manual control lever being pivotally mounted around a second axis of the housing, said lever being maneuverable between an open position and a closed position and being provided with a first return spring in the open position, a connecting rod for transmitting the closing movement of said lever to said pivoting support, having a first end driven by a lever arm of said lever and a second end pressing, during the closing movement, against a bearing surface of said pivoting support, causing the rotation of said support around said first axis and the closing of the contacts, a lever of locking being articulated on said pivoting support, ensuring the maintenance of said second end of said connecting rod against lad ite bearing surface of said support during the closing movement and during the closed position of the contacts, means for unlocking said locking lever acting, in the event of an electrical fault, against a second return spring of said lever, allowing the automatic opening of the circuit breaker, independently of the operation of the control lever, by authorizing the breaking of the support between said second end of the connecting rod and said bearing surface of said support, said breaking being ensured by a third spring causing sliding of said second end of said connecting rod against said surface, and causing the opening of the contacts, said same third spring ensuring, in the closed state of the contacts, the contact pressure.

Such a circuit breaker is described for example in the German document DE-A-2 943 696.

In this document, the pivot axis of the pivoting support is located at its opposite end with respect to the point of contact and the bearing surface of the pivoting support against which rests the second end of the connecting rod is located between the contact point and said axis.

Furthermore, the pivoting support is articulated on this axis, called the first first articulation axis above, by a light ensuring play and thus allowing a certain displacement of this end of the support relative to the fixed axis. Finally, the third spring, which ensures the opening of the contacts and also the contact pressure in the closed state of the circuit breaker, tends to rotate the pivoting support around the fixed point which constitutes, in this state, the second end of the connecting rod. The play in the articulation of the support allowing a certain wear of the contacts.

However, in this arrangement, this clearance is a drawback in the case of automatic opening of the circuit breaker due to a fault because it delays the opening of the contacts. Indeed, when the support of the connecting rod breaks against the pivoting support, the third spring will cause, before the rotation of the pivoting support around its articulation axis, the adjustment of the clearance, delaying the separation of the contacts. This delay is obviously harmful and is commonly called: contact decay time.

The object of the present invention is to overcome this drawback and to produce a circuit breaker with very rapid opening in the event of a fault appearing actuating the means for unlocking the locking lever, without the actual opening of the contacts being dependent on '' a time of contact decenetration.

The invention thus relates to an electrical circuit breaker of the type defined above in the introduction, characterized in that said pivoting support is articulated, without play, around said first axis located between said movable contact and said bearing surface of the second end of said connecting rod, in that said first end of the connecting rod which is driven by a lever arm of the control handle, is linked to this arm by a third articulation axis with the possibility of a small translation of said connecting rod with respect to said arm, in the closed position of the circuit breaker, in a direction substantially merging with the line joining said third axis to said fulcrum of the second end of the connecting rod against said bearing surface of said pivoting support, said third spring having a first end hooked on said pivoting support, between said first axis and said bearing surface and the second end of which exerts a force on said connecting rod.

According to a preferred embodiment of the invention, the second end of said third spring is hooked on a pivoting plate articulated around a fourth axis linked to the housing, said pivoting plate having a guide means securing said first end of the connecting rod, the force of said third spring on said connecting rod being exerted by means of said guide means, the point of attachment of said third spring on said pivoting plate being chosen so that the force exerted on the first end of the rod by said guide means is amplified relative to the force of the spring on its attachment point.

According to another characteristic of the invention, a latching lever is pivotally mounted on said fourth axis, the end of said latching lever comprising a hook coming to bear, during the closing phase of the circuit breaker, against a stop for attaching said pivoting support, stopping the rotation of said support before approaching the contacts, the continued actuation of the control lever in the closing direction causing, by the rotation of said pivoting plate, driven by the first end of the connecting rod, the rotation of said latching lever by pressing one side of the pivoting plate against a stop of said latching lever, allowing the lever to unhook and the abrupt closure of the contacts by the action of said third spring causing a longitudinal displacement of the connecting rod.

• La figure 1 est une vue générale d'un disjoncteur électrique selon l'invention, avec la partie supérieure du boîtier ôtée.
• La figure 2 est une vue agrandie d'une partie de la figure 1 montrant le mécanisme de fonctionnement, dans la position ouverte.
• La figure 3 est également une vue montrant le mécanisme de fonctionnement mais dans une position intermédiaire au cours d'une manoeuvre de fermeture du disjoncteur.
• La figure 4 montre le même mécanisme de fonctionnement à la fin de la phase de fermeture, et correspond à la position représentée sur la figure 1.
• La figure 5 montre un état intermédiaire du mécanisme lors d'une ouverture automatique du disjoncteur, indépendamment de toute action sur la manette 16.

We will now give the description of an example of implementation of the invention, given below with reference to the appended drawing in which:

• Figure 1 is a general view of an electric circuit breaker according to the invention, with the upper part of the housing removed.
• Figure 2 is an enlarged view of part of Figure 1 showing the operating mechanism, in the open position.
• Figure 3 is also a view showing the operating mechanism but in an intermediate position during a closing circuit breaker maneuver.
• FIG. 4 shows the same operating mechanism at the end of the closing phase, and corresponds to the position shown in FIG. 1.
• FIG. 5 shows an intermediate state of the mechanism during an automatic opening of the circuit breaker, independently of any action on the lever 16.

Referring now to the figures, the circuit breaker shown comprises a housing 1, of which only the lower part is seen, the upper part being removed to allow the mechanism to be seen.

This box has terminals 2 and 3 for input and output connection of the circuit breaker.

Inside the housing are housed a movable contact 4 and a fixed contact 5. The fixed contact 5 is electrically connected to terminal 2 by a conductor 6. To this fixed contact 5 is connected a first arcing horn 7 which extends to an arc extinguishing chamber 8 constituted by a stack of sheets.

The opposite side of the arc extinguishing chamber 8 is delimited by a second arcing horn 9 connected to the connection terminal 3. The movable contact 4 is connected to this second arcing horn 9 by a flexible braid 10 then by a conductor 11 heating a bimetallic strip. To the fixed and mobile contacts are fixed contact pads 12 and 13.

The movable contact 4 is linked to a pivoting support 14.

The movable contact 4 and its pivoting support 14, pivot around a first fixed axis 15 secured to the housing 1.

A manual control lever 16 is pivotally mounted around a second fixed axis 17 of the housing 1.

This control handle is operable between an open position as shown in FIG. 2 in solid solid line and a closed position as shown in FIG. 1 and 4. This control handle 16 is provided with a first return spring 18 acting in the direction of the return of the lever to the open position of the circuit breaker.

A connecting rod 19 has a first end provided with a third hinge pin 20 which is engaged in an oblong opening 21 of the control handle 16. The handle 16 constitutes a lever of which a first arm is constituted by the part external to the housing and on which an operator can act and whose part which goes from the second axis 17 to the lumen 21 constitutes a second lever arm. Thus, the connecting rod 19 can pivot about its axis 20 while this axis 20, integral with the connecting rod, can itself undergo a small translation in this light 21. The connecting rod 19 has a second end provided with an axis of support 22 which, during the manual opening and closing operation of the circuit breaker and during the closed position of the circuit breaker, bears against a support surface 23 of the pivoting support 14. This second end of the connecting rod 19 is also supported by the support axis 22 against a second support surface 24 of the pivoting support 14. This second support face prevents the rod from rotating around the third articulation axis 20, in the clockwise direction , when the circuit breaker is in the open position (Figure 2).

The first fixed axis 15 is located between the movable contact 13 and the bearing surface 23 of the pivoting support 14. On this fixed axis 15, the pivoting support 14 is articulated without play.

When the circuit breaker is in the closed position, as shown in FIGS. 1 and 4, it can be seen that the oblong opening 21, which is moreover open at its peripheral end, is directed in a direction which substantially merges with the line which joins the third articulation axis 20 and the support axis 22. In addition, in this same position, the angle made by the support face 23 with this direction is slightly obtuse.

A locking lever 25 is articulated on the pivoting support 14 around the same first fixed axis 15. This locking lever 25 maintains the second end of the connecting rod 19, by its bearing axis 22 against the bearing surfaces 23 and 24 by preventing the sliding of the support axis 22 against the oblique support surface 23. This lever 25 is subjected to a second return spring 26 acting in the direction of closing of this lever against the face d support 23 of the pivoting support 14.

Means for unlocking the locking lever 25 are provided: it is a thermal trip device constituted by the bimetallic device 11 secured to an unlocking pull tab 27, the left end of which passes under the mechanism and has a rim. In the event of an electrical overload, this device moves to the right and the flange of the tongue 27 comes to bear against the lower end of the locking lever 25 thus allowing the connecting rod 19 to escape from the bearing surface under the action of a third spring 28 whose exact function will be described later. A second unlocking means is provided, it is an electromagnetic trip device 29 comprising a piston 30 and a pusher 31 which, in the event of a short circuit also pushes the lower end of the locking lever 25.

The third spring 28 cited above is on the one hand hooked on the pivoting support 14 while its other end exerts a force on the connecting rod 19. In the example described, this traction on the connecting rod 19 is exerted by the intermediate a pivoting plate 32 articulated around a fourth axis 33 linked to the housing 1. This plate 32 has a guide light 34 securing the third axis 20 of the first end of the connecting rod 19. It is by the support from the upper end of this lumen 34 of the plate 32 against the axis 20 of the end of the connecting rod that the spring 28 exerts its tensile force on the connecting rod.

The attachment point 35 of the spring 28 on the plate 32 is located at a greater distance from the axis 33 than the distance separating this axis 33 from the upper end of the light 34 which bears, in the closed position of the circuit breaker, figures 1 and 4, against the axis 20, located at the first end of the connecting rod 19, thus creating, at this end, a force greater than that exerted by the spring on its attachment point 35. This plate 32 therefore has on the first end of the connecting rod 19 an amplifying effect of the action of the spring on its attachment point 35.

On the other hand, the point of attachment 36 of the spring 28 on the pivoting support 14 is located at a shorter distance from the first axis 15 than the distance separating this axis 15 from the bearing surface 23 of the pivoting support 14.

Thus, in the closed position of the circuit breaker, the force exerted by the support face 23 of the pivoting support 14 against the support axis 22 of the second end of the connecting rod 19 is reduced relative to the force exerted by the spring on its attachment point 36.

Thus, in the closed position of the circuit breaker, the spring 28 exerts on the connecting rod 19 two opposite but unequal forces, creating a differential force having the result of pushing the connecting rod 19 towards the bearing surface 23 of the pivoting support 14. This effort s exerts directly on the face 23 because the axis 20 of the first end of the connecting rod 19 is not fixed but located in an oblong opening 21 of the lever 16. This differential force ensures the contact pressure.

This differential force, in the direction indicated above, only exists as long as the second end of the connecting rod is in abutment, by its bearing axis 22, against the bearing surface 23. Thus, if an electrical fault occurs product, short-circuit or overload, the corresponding unlocking means, the electromagnetic trip device 29 for example, causes the locking lever 25 to tilt, which allows the axis 22 to escape by sliding on the oblique support face 23 As soon as the exhaust is produced, which is almost instantaneous, this differential force disappears immediately and the force of the spring then makes the pivoting support 14 pivot about its axis 15, thus ensuring the separation of the contacts.

It can thus be seen that, thanks to the proposed device of the invention, the opening of the contacts in the event of a fault is very rapid because, as soon as the support at 22, 23 breaks, the force of the spring 28 acts directly to tilt the pivoting support 14, without there being any catch-up time for "contact decenetration".

FIG. 5 shows an intermediate state of the mechanism during such an automatic triggering.

We see that the locking lever 25 has tilted, pushed by the pusher 31. The connecting rod 19 has escaped from its support 23, the contacts 4, 5 are separated.

At the end of the opening phase, we are in the position shown in FIG. 2, the return spring 18 has caused the lever 16 to tilt to the right in the open position, the connecting rod 19 has been driven to the left by the light 21 of the lever and its other end 22 is dropped on the face 24.

During manual opening of the circuit breaker, by action on the lever 16, there is no break in the support of the connecting rod 19 at 22, 23, the locking lever 25 not being actuated. The axis 20 of the first end of the connecting rod 19 is driven by the lumen 21 of the lever 16.

The movement of the axis 20 in the lumen 34 of the plate 32 brings all the parts back to the position of FIG. 2.

Finally, the mechanism further comprises a system allowing, when the circuit breaker closes, the abrupt closing of the contacts.

To this end, an attachment lever 37 is pivotally mounted on the fourth axis 33. The end of this lever carries a hook 38 (clearly visible in FIG. 3) which comes to bear during the closing phase of the circuit breaker, against a hooking stop 39 of the pivoting support 14. The mechanism is then in the intermediate position shown in FIG. 3. The further operation of the lever in the direction of the arrow F drives the axis 20 by the light 21, the support pivoting 14 can no longer pivot because of the hook 38 which prevents it, the support of the axis 20 against the upper wall of the lumen 34, causes the rotation 32 of the plate 32 about its axis 33 In this rotation, a bearing face 40 of the plate 32 comes lean against a stop 41 of the latching lever 37, causing in its rotation the latching lever 37. At the end of the course of the lever 16 (FIG. 4) the axis 20 of the first end of the connecting rod is at the upper end of the lumen 34 and the hook 38 escapes its hooking stop 39. An abrupt rotation of the pivoting support 14 then takes place thanks to the differential force described above which pushes the connecting rod 19 longitudinally. The abrupt closure of the contacts is thus obtained.

At the end of the maneuver, the locking of the axis 20 of the connecting rod 19 on the plate 32 is obtained by a recess at the end of the lumen 34, the axis 20 thus locked makes it possible to position the lever 16 in the closed position by its light 21.

The plate 32 has a stop 50 which, in the open position of the circuit breaker, limits its rotation.

When the lever 16 is moved to the closed position, the pivoting support 14 is caused to rotate, by means of the connecting rod 19. As soon as the pivoting support 14 is stopped in its rotation by the hooking stop 39 , the continuation of the action on the lever 16 causes the rotation of the plate 32 which leaves its stop 50 on the axis 17. It is at this instant that there are two different forces exerted by the spring 28 on the ends of the connecting rod 19 mentioned above.

Claims (3)

1. Circuit breaker comprising a fixed contact (5) and a mobile contact (4) joined to a support (14) pivoting about a first pin (15) fixed to a casing (1), a manual operation lever (16) pivoting about a second pin (17) of the casing, said lever being manoeuvrable between an open position and a closed position and being provided with a first return spring (18) biasing it towards the open position, a link (19) for transmitting closing movement of said lever (16) to said pivoting support (14) having a first end (20) driven by a lever arm of said lever and a second end (22) bearing during the closing movement against a bearing surface (23) of said pivoting support (14) causing rotation of said support about said first pin (15) and closure of the contacts (4, 5), a locking lever (25) being articulated to said pivoting support (14), holding said second end (22) of said link (19) against said bearing surface (23) of said support during the closing movement and in the closed position of the contacts, means (11, 27, 29) for unlocking said locking lever (25) operating in the event of an electrical fault against a second return spring (26) of said lever, enabling automatic opening of the circuit breaker, independent of the operation of the manual operation lever (16) by enabling breaking of the bearing engagement between said second end (22) of the link (19) and said bearing surface (23) of said support (14), said breaking being achieved by a third spring (28) causing sliding of said second end (22) of the link against said surface (23) and causing opening of the contacts (4, 5), said third spring (28) providing the contact pressure when the contacts are closed, characterised in that said pivoting support pivots without clearance on said first pin between said mobile contact and said bearing surface at the second end of said link, in that said first end (20) of the link (19) which is entrained by a lever arm of the operating lever (16) is joined to this arm by a third pivot pin (20) with the facility (21) for slight movement in translation of said link (19) relative to said arm, when the circuit closed, in a direction substantially coincident with the line joining the third pin (20) to said point at which the second end (22) of the link bears against said bearing surface (23) of said pivoting support, said third spring (28) having a first end joined to said pivoting support between said first support (15) and said bearing surface (23) and whose second end exerts a force on said link (19).
2. Circuit breaker according to claim 1 characterised in that the second end of said third spring is attached to a plate (32) pivoting on a fourth pin (33) joined to the casing (1), said pivoting plate (32) having guide means (34) controlling said first end (20) of the link, said third spring (28) exerting force on said link (19) through the intermediary of said guide means (34), the attachment point (35) of said third spring (28) to said pivoting plate (32) being such that the force exerted on the first end (20) of the link by said guide means (34) is amplified relative to the spring force at its attachment point (35).
3. Circuit breaker according to claim 2 characterised in that a detent lever (37) pivots on said fourth pin (33), the end of said detent lever comprising a hook (38) bearing, during closing of the circuit breaker, against a detent abutment (39) of said pivoting support (14), stopping rotation of said support before interengagement of the contacts, further movement of the operating lever (16) in the closing direction causing, by virtue of rotation of said pivoting plate (32) entrained by the first end (20) of the link (19), rotation of said detent lever (37) relative to a surface (40) of the pivoting plate (32) against an abutment (41) of said detent lever, enabling release of the lever and sharp closing of the contacts by the action of said third spring (28) causing longitudinal displacement of the link (19).

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