EP1505619B1 - Ameliorated lock mechanism for circuit breakers and circuit breaker incorporating such lock - Google Patents

Description

The present invention relates to the general technical field of electrical appliances and more particularly to the field of modular devices, circuit breakers type for a line protection or switches for personal protection.

The present invention relates in particular to a lock mechanism for a circuit breaker magneto-thermal circuit breaker or switch or similar device, especially for phase circuit breaker. It also relates to circuit breakers equipped with this mechanism.

The line protection circuit breakers comprise, in a housing, an electrical circuit extending between two terminals and comprise a thermal trip bimetallic strip for the protection of the line against overloads and an electromagnetic disjunction element comprising a coil with a plunger core. associated with a striker, to ensure, in the event of a short circuit, disjunction by opening a movable contact cooperating with one or more fixed contacts. The phase and neutral circuit breakers comprise, in addition to the phase stage as described, a neutral stage with fixed and movable contacts, the moving neutral contact being actuated jointly with the moving phase contact.

The actuation of the movable contact is generally carried out by a lock mechanism, of the knee-type, usually comprising a lever-type control member, operable manually and driving a rod tending to push back a pivoting contact holder which carries one or more movable contacts. to bring them each into pressure contact against a fixed contact, to a position in which the return in the opposite direction, to the contact opening, is normally prevented by a pawl prohibiting the rod, kneeling support on the door -contacts, to escape and to release this one. Manual opening is done by pressing the lever in the opposite direction. The disjunction is generally caused by action of the bimetallic strip or striker of the coil against a trigger lever so as to cause the release of the pawl and thus the escape of the rod, thereby opening the electrical contact.

Such a lock mechanism is described for example in the European patent EP-0 570 647 B1 .

For example, there is known a lock mechanism actuating at least one movable electrical contact, moving relative to a fixed electrical contact between two stable positions respectively corresponding to an opening and closing of an electrical circuit, said lock mechanism comprising a bimetallic thermal trip.

Known lock mechanisms also have disadvantages. Indeed, electrical devices, and in this case the circuit breakers incorporating such a lock mechanism are subject, depending on the geographical installation areas at varying atmospheric humidity.

These are responsible for dimensional variations of the hydrophilic plastic materials of internal organs making in particular supports for the lock mechanism or for other functional parts. These variations, corresponding to a relative displacement of the bimetallic strip and the lock mechanism, can affect the tripping times of the circuit breaker.

The purpose of the present invention is therefore to overcome these drawbacks and to achieve a circuit breaker whose release times are not affected by moisture problems, deformation of the functional parts.

First, for this purpose, the thermal trip bimetal is fixed on a carcass, on which is mounted the movable electrical contact. Such a configuration is apparent from the document U.S. 2,209,352A .

It is thus possible to eliminate the plastic casing of the kinematic chain of the thermal release of the bimetallic strip. The housing does not influence this release, and the use of a hydrophilic material is possible.

The bimetallic strip can also be integrated in the lock mechanism without increasing its bulk. This releases a volume in the circuit breaker for other features. Mounting bimetallic directly on the lock mechanism also simplifies the constituent parts of a circuit breaker and in particular to reduce the number of its constituent elements.

Such a configuration also makes it possible to maintain the same tripping threshold for the bimetallic strip, regardless of any deformation or relative displacement, of parts constituting the lock mechanism. No intervention, during the lifetime of an apparatus incorporating the lock mechanism according to the invention, is necessary to readjust the trip threshold of the thermal trip bimetallic.

A subassembly incorporating the bimetallic strip is obtained which does not alter the distance between the free end of the bimetallic strip and a drive member integral with a release and capable of being actuated by the bimetallic strip.

The carcass, which is metallic or plastic, consists of two flanges respectively lower and upper.

According to the invention, the lock mechanism comprises a trigger pivotally mounted on the carcass and able to actuate the moving electrical contact, the trigger comprising a drive member cooperating with the free end of the bimetal and capable of rotating said trigger under the action of the thermal trip bimetallic strip.

The trigger and the drive member are for example made in one piece of plastic material.

According to an exemplary embodiment, the lock mechanism comprises means of catch-up comprising a pivoting mounting of the movable contact on the carcass, and this against an elastic return means generating a displacement of said movable contact resiliently biased by relative to said carcass when establishing the electrical connection with the fixed contact.

The invention also relates to an electric line protection device or protection of persons comprising a lock mechanism as presented above.

• un boîtier extérieur en matière plastique, présentant une configuration en deux demi-coquilles,
• des moyens d'assemblage des demi-coquilles,
• des moyens de fixation sur un support du type rail,
• au moins deux bornes de connexion électrique,
• un organe d'actionnement déplaçable entre deux positions stables,
• un sous-ensemble magnétique comportant un percuteur permettant d'interrompre la liaison électrique,
• et un mécanisme de serrure tel que décrit ci-dessus.

The present invention also relates to a circuit breaker comprising:

• an outer casing made of plastic, having a configuration in two half-shells,
• means for assembling the half-shells,
• fastening means on a support of the rail type,
• at least two electrical connection terminals,
• an actuating member movable between two stable positions,
• a magnetic subassembly comprising a striker for interrupting the electrical connection,
• and a lock mechanism as described above.

• la figure 1 est un exemple de réalisation, en vue éclatée, d'un mécanisme de serrure conforme à l'invention ;
• les figures 2 et 3 sont vues en coupe du mécanisme de serrure de la figure 1, dans des états de fonctionnement différents ;
• les figures 4 et 5 sont des représentations schématiques et partielles d'un disjoncteur conforme à l'invention, avec respectivement une liaison électrique fermée et ouverte ;
• les figures 6 et 7 sont des vues extérieures partiellement découpées d'un disjoncteur conforme à l'invention.

Other features of the invention will also emerge from the detailed description given below, by way of non-limiting example, with reference to the drawings in which:

• the figure 1 is an exemplary embodiment, exploded view, of a lock mechanism according to the invention;
• the Figures 2 and 3 are sectional views of the lock mechanism of the figure 1 in different operating states;
• the Figures 4 and 5 are schematic and partial representations of a circuit breaker according to the invention, with respectively a closed and open electrical connection;
• the figures 6 and 7 are partially cut out external views of a circuit breaker according to the invention.

The lock mechanism, according to the invention, shown in exploded view at the figure 1 is intended to be integrated in an electrical appliance, for example a circuit breaker. The lock mechanism actuates a movable electrical contact (1) intended to bear on a fixed electrical contact (2) represented for example in Figures 4 to 7 .

The lock mechanism also comprises a bimetallic strip (3) for thermal tripping, integral with a constituent element of said lock mechanism. The lock mechanism consists for example of a lower flange (4) surmounted by an upper flange (5) on which is fixed the bimetal (3). The latter is for example fixed on the upper flange (5) by one or more points of welding. The lower flanges (4) and upper (5), assembled by any known mechanical means, are made with electrically conductive materials for example copper type.

This construction is particularly advantageous insofar as it does not increase the size of the lock mechanism. In addition, no means or additional mounting or fixing member for the bimetallic strip (3) is necessary. The latter is therefore an integral part of the lock mechanism. The lower flanges (4) and upper (5) thus constitute a carcass of the contact carrier, with which is secured the bimetallic strip (3) thermal trip. The carcass is for example metallic.

The lower flange (4) is also provided with an axis (6) on which is mounted pivoting a trigger (7). The latter is made of an electrical insulating material. The trigger (7) separates the mobile electrical contacts (1) and fixed (2) in case of overcurrent and thanks to its pivoting allowing it to cause the movable electrical contact (1). One end of the release (7) is supported on the movable electrical contact (1) so as to rotate the latter and separate it from the fixed electrical contact (2).

The movable electrical contact (1) is advantageously mounted in or on the metal carcass consisting of the lower flanges (4) and upper (5). This assembly is obtained by means of a pivot axis (1 a) engaged in corresponding openings (5 a) even in the lower flanges (4) and upper (5).

A return spring (8) is for example mounted with its ends between the movable contact (1) and the lower flange.

The movable contact (1) can therefore pivot relative to the carcass on or in which it is mounted.

The trigger (7) comprises a drive member (9) capable of pivoting said trigger (7) under the action of the bimetallic strip (3) thermal trip. The drive member (9) is located at one end of the trigger (7) and extends substantially orthogonal to the direction of longitudinal extension of said trigger (7). The drive member (9) has a clearance (10) through which the movable electrical contact (1) and the free end of the bimetallic strip (3) pass. This clearance (10) is delimited by a first support edge (7a) and a second support edge (9a). The first support edge (7a) is intended to come into contact with the movable contact (1) and drive the latter to obtain the opening of the electrical connection. The second support edge (9a) provides a support for the bimetallic strip (3), which, by deforming, drives the drive member (9) and consequently also a trigger (7) ready to release the electrical contact. fixed (2) by pivoting the movable electrical contact (1) in the same manner as previously described.

The figure 4 represents a closed electrical connection between the movable (1) and stationary (2) electrical contact and a corresponding positioning of the lock mechanism. The bimetallic strip (3) is in its inactive, undistorted position.

On the figure 5 the deformed bimetallic strip (3), for example as a result of an overcurrent, displaces the drive member (9), and consequently the trigger (7), so as to separate the movable (1) and fixed (2) electrical contacts. ).

The lock mechanism also comprises wear stroke compensating means. The means of catching the wear race comprise a pivoting mounting of the movable contact (1) on the carcass. This pivoting assembly is carried out by means of an elastic return means, against a restoring force biasing the movable contact (1) relative to the carcass and generating a displacement of said movable contact (1) relative to the carcass when establishing the electrical connection with the fixed contact (2). It absorbs and variations of dimensions or shapes related to moisture or expansion / contraction of certain parts by deformation of the housing, related to hygrometry.

The circuit breaker according to the invention also comprises an actuating member (11) movable between an active stable position ( figure 4 ) and an inactive stable position ( figure 5 ). The actuating member (11) is automatically returned to its inactive position when the trigger (7) is pivoted as shown in FIG. figure 5 .

The trigger (7) and the drive member (9) are for example made in one piece, for example plastic.

The circuit breaker according to the invention shown in Figures 4 to 7 comprises an outer casing (12) of plastic material and fastening means (13) on a support of the rail type (not shown). The circuit breaker comprises the actuating member (11), movable between two stable positions, the active one represented at figure 4 and the other inactive represented at the figure 5 , for manually controlling the activation of said circuit breaker.

The outer casing (12) comprises for example two half-shells. Assembly means of the two half-shells are also provided.

The circuit breaker comprises a magnetic subassembly (14) comprising a striker (15) which separates the movable contact (1) from the fixed contact (2). The magnetic subassembly (14) is associated with the fixed electrical contact (2) via an induction coil (16).

The circuit breaker according to the invention also comprises a lock mechanism as described above. The latter is represented for example in figures 6 and 7 in two positions respectively corresponding to a separation and closure of the fixed (2) and movable (1) electrical contacts. In the first position represented in figure 6 , the lock mechanism is switched to an inactive position following the deformation of the bimetallic strip (3) or to a thrust exerted on the trigger (7) by the striker (15). The bimetallic strip (3) thermal trip is shown for clarity in its two positions, one deformed, the other undistorted, to figures 6 and 7 .

The circuit breaker according to the invention also comprises two connection terminals (17), the first of which is directly connected to the induction coil (16) at one of its ends and the second of which is directly connected via a connecting wire (18) bimetallic strip (3) thermal trip.

When the actuating member (11) is reset (return to its active position), the latter causes the lock mechanism to tilt in a position corresponding to the closing of the fixed (2) and movable (1) electrical contacts. Actuation of the lock mechanism via the actuating member (11) is achieved by means of a link (19) connecting said actuating member (11) to the lock mechanism.

The rod (19) has a U-shape, a first leg (19a) is engaged in the control member (11), and eccentrically relative to the pivot axis (11a) of said control member (11), and a second branch (19b) is engaged in a slot (4a) of the lower flange (4).

The forms and operation of an exemplary embodiment of such a lock mechanism are described for example in the document EP-0 570 647 .

The second branch (19b) can move in a slot (4a), in particular during the pivoting of the control member (11). The light (4a) also has an inclined portion (4b) in which the second leg (19b) is held, and this, thanks to a pawl (7b) formed by the other end of the trigger (7).

If the electrical contacts (1 and 2) are in the closed position ( figure 2 ), a deformation of the bimetal (3), pushes the drive member (9) in the trigonometric direction, and causes the trigger (7) to pivot. The pivoting of the trigger (7) ( figure 3 ) moves the pawl (7b) and releases the second leg (19b). An inclined portion (4b), associated in particular with an additional return spring mounted for example between the lower flange (4) and the housing (12), causes the second branch (19b) to escape into the lumen (4a) and the pivoting of the metal casing in the trigonometric direction, leading to the opening of the electrical contacts (1 and 2).

The connecting wire (18) consists for example of a conductive braid.

The lock mechanism, and therefore the circuit breaker according to the invention, has the significant advantage that the bimetallic strip (3) is only associated with a single conductive braid connecting it to a connection terminal ( not shown), the other electrical connection being via the metal frame consisting of the lower flanges (4) and upper (5) and carrying the contact carrier.

In the exemplary embodiments in accordance with the invention, the dimensional or shape variations related to the humidity, wear or expansion / contraction of certain parts are thus absorbed, and the tripping threshold of the bimetal (3). remains unchanged.

Claims (6)

1. Lock mechanism activating at least one movable electrical contact (1), which moves relative to a fixed contact (2) between two stable positions corresponding respectively to the opening and closing of an electric circuit, said mechanism comprising a bimetallic strip (3) for thermal tripping which is fixed onto a body formed by two shields, a lower shield (4) and an upper shield (5), and on which body the movable electric contact (1) is mounted, characterised in that it comprises a tripping device (7) mounted pivotably on the body and being able to activate the movable electric contact (1), the tripping device (7) comprising a drive unit (9) cooperating with the free end of the bimetallic strip (3) and being able to pivot said tripping device from the action of the bimetallic strip (3) for thermal tripping.
2. Lock mechanism according to claim 1, characterised in that the tripping device (7) and the drive unit (9) are made in one piece from plastic material.
3. Lock mechanism according to any of claims 1 to 2, characterised in that the body is made of metal or plastic.
4. Lock mechanism according to any of claims 1 to 3, characterised in that it comprises means for adjusting the course comprising the pivotable mounting of the movable contact (1) on the body, such that it is against an elastic return means causing the displacement of said movable contact (1) applied elastically relative to said body during the establishment of the electrical connection with the fixed contact (2).
5. Electrical device for protecting the power line or protecting people comprising a lock mechanism according to any of claims 1 to 4.
6. Circuit breaker comprising:

   - an outer casing (12) made of plastic material having the form of two half shells,

   - means for assembling the two half-shells,

   - securing means (13) for fixing onto a rail type support,

   - at least two electric connecting terminals

   - an actuator (11) which can be displaced between two stable positions,

   - a magnetic subassembly (14) comprising a striker (15), making it possible to separate the movable contact (1) from the fixed contact (2),

   - and a lock mechanism according to any of claims 1 to 4.

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