IL193201A

IL193201A - Mobile-spindle lock mechanism

Info

Publication number: IL193201A
Application number: IL193201A
Authority: IL
Original assignee: Hager Electro Sas
Priority date: 2006-02-03
Filing date: 2008-08-03
Publication date: 2011-10-31
Also published as: CN101410926B; BRPI0706900B1; PL1816665T3; DE602006009369D1; MY143594A; IL193201A0; ATE443921T1; ES2333156T3; EP1816665A1; AU2007211406B2; EP1816665B1; WO2007088284A1; RU2398305C2; RU2008135162A; CN101410926A; BRPI0706900A2; AU2007211406A1; ZA200807400B; HK1126570A1

Abstract

The mechanism has movable contacts (4) connected rigidly to a contact holder (17) and pivoted between two positions of a fixed contact. A movable trigger (5) has a ratchet (9) maintaining a connecting rod (3) by supporting against the holder in locking and unlocking positions. A spiral spring (6) is constituted of end branches (16a, 16b), where the branch (6b) is connected to the holder by a welded portion to displace a pivoting axle with respect to support zones of the contacts. The branch implements a pressure support for each movable contact on the fixed contact.

Description

53552 mx.

MOBILE-SPINDLE LOCK MECHANISM yj†>$ X)vn ^mn Tiny TDJOO Mobile spindle lock mechanism The present invention concerns a lock mechanism for electrical appliance for protecting lines and people of the circuit breaker type comprising at least one mobile contact designed to cooperate with one or several fixed contacts. A mechanism of this type is mobile between a locked position for closing and an unlocked position for opening the line(s) controlled by the electrical appliance.

This electrical appliance comprises an operating member which makes it possible to control a change of position of the lock mechanism and, if applicable, corresponds to any unlocking thereof, for example due to the occurrence on at least one line of electrical conditions incompatible with the maintenance of the locked position. The operating member is traditionally linked to the lock mechanism using a link rod.

Traditionally, a lock mechanism comprises at least one mobile contact supported by a contact holder pivoting along a first axis between two positions bearing on and away from a fixed contact, respectively. During locking of the mechanism, a stress coming from one end of the link rod, stemming from the operating member, is transmitted to the contact holder(s).

The lock mechanisms serve to mechanically amplify the energy provided by measurement systems, and their amplification principle rests on a mechanical system fed by a spring, the unstable equilibrium of which is ensured essentially through frictional stresses. These are implemented in particular at the aforementioned end of the link rod and the contact holder(s).

In case of a problem on the line, a mobile trigger passes on information to the mechanism which is provided by one of the measurement systems, usually magnetic or thermal, in order to unlock it when it is in the closed position of the contacts. This trigger comprises a member allowing maintenance of the link rod bearing on the contact holder(s), in the locking phase and the locked position.

When the trigger moves and releases the end of the link rod, the frictional stable mechanical relationship mentioned above is undone, allowing unlocking of the mechanism.

Means for returning the contact holder to the open position of each mobile contact, i.e. away from a fixed contact, are implemented once the link rod is released.

To ensure the stability of the lock mechanism in the closed position, it must comprise a deformable structure. The possibility of deformation is, in known locks, ensured by elastic means which in general allow a relative movement between several pieces and implementation of a bearing pressure of each mobile contact on a fixed contact.

Other than the mechanical stability of the lock in the closed position, these elastic means make it possible to ensure sufficient pressure to avoid electrical problems upon closing of the circuit, making the circuit breaker much more reliable and avoiding the progressive deterioration of the fixed and mobile contacts. These means also enable the absorption of wear of the contacts.

In certain known configurations, the means for returning the contact holder to the open position, mobile contact away from the fixed contact, and the elastic means for implementation of a bearing pressure of one on the other, are ensured by two separate springs.

There are, however, also configurations in which a single spring simultaneously performs both functions. This is the case for the system described in patent EP 0 506 503, in the applicant's name.

In both scenarios, the assembly of the lock unit, involving a particular positioning of the spring(s), is in general not easy to automate, and is therefore less economically favorable in terms of industrialization of the assembly of electrical appliances.

In the case where a spring is inserted between the mobile contact and the contact holder(s), the structure is more complex, in particular due to the number of pieces to be assembled according to mobile connections, and because the installation of the springs requires locking of their ends so that they perform their return function. This complexity has a direct impact on the production cost of the product.

This assembly problem of the ends of the spring is also found in the solution described in document EP 0 506 503 for the single spring implemented.

One of the objectives of the present invention is to decrease the cost of the industrialization of appliances, and therefore to simplify the lock mechanism itself as much as possible, as well as its assembly in appliances. An original configuration was designed to meet this objective.

One of the major advantages resulting from the new design is avoiding adjustments once the lock mechanism is mounted in the case.

To meet these objectives, and others which will become clear upon reading the following description, the lock mechanism according to the invention is primarily characterized in that each mobile contact is rigidly linked to the contact holder(s), and in that the elastic means for implementing the bearing pressure of each mobile contact on a fixed contact are linked to the contact holder through a link ensuring the movement of the first pivot axis in relation to the mobile contact / fixed contact bearing area(s) once said bearing takes place.

The rigidity of the mobile contact / contact holder link allows a considerable simplification of the technical solution, as well as the industrialization process which then only manages a rigid and compact assembly instead of several separate pieces constituting the lock mechanism as in most of the solutions of the prior art.

To ensure the stability of the lock in the locked position, according to a completely original solution, it is the initial pivot axis itself of the contact holder which moves in relation to the mobile contact / fixed contact bearing area. In other words, instead of providing a first movement of the mechanism to bring the contacts against each other, then a deformation around the same axis to engage the bearing as in most of the solutions of the prior art, said deformation takes place in relation to the contact area. This solution allows a significant technological simplification of the lock mechanism.

This mechanism can then comprise means for guiding the movement of the first pivot axis.

According to a first variation, these elastic means are made up of a hairpin spring with a branch of rectilinear bearing whereof one end is fixed to the case of the electrical appliance, and whereof the other end is bent perpendicularly to said branch and provides the pivot for the rotation of the contact holder along the first axis through running fit of the bend portion in an orifice of the contact holder(s).

In this scenario, the guiding is provided by the spring itself, whereof the length of the branch is obviously invariable. There is therefore no need to add external guide elements.

Advantageously, this bent portion can also serve as a pivot for the trigger.

Moreover, the means for returning each mobile contact away from a fixed contact can be made up of a hairpin spring with one branch whereof one of the ends is fixed to the case of the electrical appliance, said branch bearing on the contact holder and exerting an action on it antagonistic to that of the link rod.

These return means are then formed in the same way as the elastic means authorizing the movement of the first pivot axis, from which they are, however, separate.

This analogy is also found in the end of said branch, which is bent substantially perpendicularly to the plane of movement of each mobile contact, the bent end portion this time being housed in a slide channel formed in the contact holder(s).

The interest of the slide channel resides in the possibility of reorienting the stresses in relation to the branch of the spring, so that the latter works over its entire length and not in compression, for which the stiffness is very high and unproductive.

Preferably, the hairpin springs respectively of the elastic means for implementing the bearing pressure and of the return means for each mobile contact on and away from a fixed contact, respectively, are a single piece, and are connected at the level of their fixing to the case.

There then remains only one location for fixing to the case, for a single component, which further simplifies the assembly.

Also preferably, said springs can be connected by an additional branch. This can then have a rectilinear bearing, developing substantially in the direction of movement of the free end of each mobile contact.

In this scenario, fixing to the case is facilitated in particular because the spring, now in a single piece, can be clipped in an outgrowth of the case provided for this purpose.

The contact holder / mobile contact assembly is therefore no longer pivoting directly in relation to the case, but can be considered "floating" in relation to the latter, provided with the possibility of moving according to a complex movement not limited to simple pivoting.

According to another variation, the elastic means for implementation of an elastic bearing of each mobile contact on a fixed contact consist of a spring comprising a hairpin branch whereof one end is connected to the case of the electrical apparatus, said branch being positioned at rest so as to be deformed by the contact holder in movement during locking once a mobile contact / fixed contact bearing takes place, the contact holder being connected to the case by a contact link inserted in a housing or a groove authorizing its pivoting along the first axis and guiding its movement in relation to the mobile contact / fixed contact bearing area.

In this scenario, the branch of the hairpin spring is not used to guide the movements of the contact holder(s), which is provided by the contact link / housing or groove.

At this stage, there is no question of the elastic means allowing a mobile contact / fixed contact bearing pressure.

The same branch can, however, be positioned at rest so as to be deformed by the contact holder during all of its movement, in order also to serve as means for returning each mobile contact away from a fixed contact.

As in the preceding configuration, the same spring is then used to realize the means for returning each mobile contact away from a fixed contact on one hand, and the elastic bearing pressure means on the other hand.

According to one scenario, one of the ends of the hairpin branch is fixed to the case.

It is also possible for the hairpin branch to constitute one of the end branches of a spiral spring whereof the spiral central portion surrounds a contact and the other end branch permanently bears against a relief exceeding the case. In this case, the mechanical link of the hairpin branch with the case is certainly more complicated but has, as will be clearer later, advantages during assembly.

According to one possibility, the contact holder comprises a journal inserted according to a running fit and sliding in a housing of the case.

This link makes it possible to provide the mechanical functions belonging to this link, namely a pivoting along a first axis and a later movement, the characteristics of said link having to be combined with the return means described above for a return to the initial position in case of unlocking of the mechanism.

The housing or groove provides guiding of the journal, according to a movement which may be curvilinear and, if applicable, allow a friction of the mobile contact on the fixed contact.

This housing comprises, according to one possibility, walls erected in a U shape oriented such that the opening of the U opens in the direction of the mobile contact. Said housing is therefore not completely closed, which can be seen as an additional advantage during assembly.

Also preferably, the spiral central portion of the spring surrounds the U-shaped housing.

In such a configuration, the location of the complex mechanical link described above is also used as one of the attachment points of the spiral spring.

According to one possibility, the hairpin branch is driven by a pin exceeding the contact holder(s).

The pivot of the trigger in relation to the contact holder can be freely arranged on the contact holder(s), on the condition that the function provided by the trigger is provided. In this case, preferably, the trigger pivots around a coaxial contact at the journal mobile in the housing of the case, said contact exceeding from the surface opposite the contact holder(s).

There is therefore a single axis for the different pivots involved in the links of the contact holder with the cases on one hand, and the triggers with the contact holder on the other hand.

The contact holder can traditionally comprise a ramp whereon one of the ends of the link rod bears, said ramp cooperating with a ratchet of the trigger to maintain the end of the link rod bearing on the ramp in the locking phase and in the locked position.

It is through this ramp that the stress transmitted by the link rod during locking is transmitted to the lock mechanism. The existence of the ratchet makes it possible to maintain the end of the link rod in contact with this ramp, and therefore to transmit the effort.

According to one possibility, the mobile contact(s) is/are a single piece with the contact holder(s). In other words, there are no longer really contact holders, but a mechanism reduced to one or several mobile contacts on which the stresses necessary for the realization of the mechanism's functions are applied.

According to one possible configuration, a bimetallic strip can be rigidly made integral at the end of the mobile contact or one of the mobile contacts opposite its bearing area against a fixed contact.

Alternatively, the bimetallic strip can be a single piece with a mobile contact, which also simplifies the mobile assembly by removing one of its components.

In this scenario, the bimetallic strip / mobile contact is made integral with the contact holder in the vicinity of the mobile contact / fixed contact bearing area, and comprises a bending section whereof the free end is arranged across from an outgrowth of the trigger. The bending section develops, from the securing means to the contact holder(s), to opposite the contact area along a certain length allowing sufficient bending to actuate the trigger.

Preferably, the outgrowth of the trigger is then placed in the vicinity of the member or ratchet enabling maintenance of the link rod bearing against the contact holder(s).

The lock mechanism, in its purest form comprising one or several mobile contacts, a bimetallic strip and a trigger, becomes extremely compact and easy to assemble, and is suitable from an assembly automation perspective. The mechanism, mounted floating thanks to the particular links which connect it to the case, no longer requires any later specific adjustment.

Finally, the sharing of certain functions, such as the pivot axis, the return spring and the elastic means for pressure bearing in the first configuration, make it possible to obtain a lock mechanism which is extremely interesting economically.

The invention will now be described in more detail by way of non-limiting example only, with reference to the appended figures, in which: - figure 1 shows, in perspective view, the lock mechanism according to the first version with an operating member for its control; - figure 2 shows, in perspective view, the solution of figure 1 installed in a circuit breaker-type electrical appliance; - figures 3a and 3b show another configuration of the version of the preceding figures, installed in a circuit breaker in the closing and opening positions of the contacts, respectively; - figure 4 is a flattened perspective view of a second variation based on a spiral spring; - figures 5a and 5b illustrate two views of the mechanism from figure 4, front and rear, respectively, the contacts separated and with a magnetic motor; - figures 6a and 6b correspond to the preceding figures, with the fixed and mobile contacts engaged in pressure bearing; and - figures 7a to 7c show an alternative in which the mobile contact and the bimetallic strip are a single and same piece.

With reference to figure 1 , the lock mechanism, designated by the general reference 1 , is connected to an operating member 2 via a link rod 3. The mechanism 1 is primarily made up of a mobile contact 4, a trigger 5 and a spring 6. The latter is made up of three branches 6a, 6b, 6c and ends with two bent portions 7a, 7b.

The portion 7b serves as pivot axis for the mobile contact 4 and for the trigger 5. The bent portion 7a cooperates with the mobile contact 4 via a slide channel 8 parallel to the contact 4.

The trigger 5 comprises, at one of its ends, a ratchet 9 intended to block the end 3a of the link rod 3 bearing against a ramp 11 of the mobile contact 4. At its opposite end, the trigger comprises a shank 10 designed to cooperate with a thermal bimetallic strip.

The lock mechanism illustrated in figure 1 is intended to be mounted in the case of an electrical apparatus, for example by clipping, the fixing preferably being done at the level of the rounded part separating the portions 6b, 6c from the spring 6.

The assembly of figure 1 appears, from the opposite side and installed in the case B of an electrical appliance, in figure 2. The operating member 2 is positioned such that the link rod 3 exerts an action, via its end 3a, against a ramp 11 of the mobile contact 4 so as to cause it to pivot bearing against a fixed contact 12. This movement is done against the spring 6, and particularly its branch 6a, bearing via the bent portion 7a, in the slide channel 8, in the vicinity of the action area of the end 3a of the link rod 3.

Once the mobile contact 4 is bearing against the fixed contact 12, the deformation of the system, necessary for the mechanical stability of the locking, is done through elastic movement of the branch 6b of the spring 6, and as a result through movement of the bent end 7b.

All of the lock mechanism 1 moves inside the case (B) of the electrical appliance once the mobile contact 4 is made to bear on the fixed contact 12. This movement makes it possible on one hand to achieve correct contact pressure between the fixed and mobile contacts, and also, if necessary, to make up for wear of the electrical contacts.

As also appears in figures 3a and 3b, the trigger 5 is mounted free in rotation on the mobile contact 4 around the pivot 7b to release the end 3a of the link rod 3 through movement of the ratchet 9 in the event of an over-current or a short circuit on the line. In case of short circuit, for example, the striker 14 of a traditional magnetic motor (M) can cause it to pivot counterclockwise, causing the release of the link rod 3, then the separation of the mobile 4 and fixed 12 contacts under the effect of the branch 6a of the spring 6. The mobile contact 4 also comprises a thermal bimetallic strip 13 which is rigidly fixed to its end opposite that which can bear on the fixed contact 12.

When an over-current takes place in the circuit, the bimetallic strip 13 deforms and comes into contact against the shank 10, which it drives while also causing a rotation of the trigger 5 in the same direction as previously, and a release of the link rod 3, or the opening of the circuit.

The assembly of the lock mechanism 1 according to the invention, which makes it possible to ensure the pressure bearing of the mobile contact 4 on the fixed contact, is done using a protuberance 15 coming out from the case (B) and which is clearly shown in figure 3b. This protuberance 15, in which the spring is clipped, for example, is located at the level of the rounded part separating the bent portions 6b, 6c from the spring 6.

Another version of the device according to the invention appears in figures 4 to 6. The same references are kept when they concern the same components. In reference to figure 4, an operating member 2 is connected via a link rod 3 to a contact holder 17 to which the mobile contact 4 is rigidly connected, a trigger 5 being mounted pivoting around a pivot 18 exceeding the contact holder 17.

In this version, the spring 16 is a spiral spring comprising two end branches 16a and 16b, respectively, the latter being locked bearing on a relief 19 exceeding the case B, the latter in this case being symbolized by a rectangular portion of the envelope.

The other end 16a of the spiral spring 16 cooperates with a contact 20 exceeding the contact holder 17 which stresses the spring 16 when the contact holder turns clockwise.

The central portion of the spiral spring 16 is wound around a housing 21 in the shape of a reversed U serving to house a journal 22 exceeding the contact holder 17. This journal 22 is coaxial to the contact 18 around which the trigger 5 pivots.

Figures 5a and 5b show, according to two opposite effects, the operation of the lock mechanism, the mobile contact 4 here being away from the fixed contact 12.

In figure 5a, in particular, the case (B) portion as well as the U-shaped housing 21 are shown transparently for explanatory purposes. In this figure, the lock mechanism is unlocked, and the mechanical link between the contact holder 17 and the case (B) is defined by the journal 22 / housing 21 system. An action on the control lever 2, in order to close the circuit, leads the end 3a of the link rod 3 to exert an action against the ramp 11. The contact holder 17 / mobile contact 4 / trigger 5 assembly pivots clockwise, the journal 22 being free in rotation in the housing 21.

In reference to figure 5b, as the angular movement increases from the above starting position, the end branch of the spring 16 bends. Given the bearing of the other end 16b against the contact 19, the spring 16 then stores energy.

Once the mobile contact 4 arrives bearing against the fixed contact 12, as illustrated in figures 6a and 6b, and given that the operating lever 2 and, as a result, the link rod 3 continue their movement before definitive blocking in the locked position, the journal 22 moves in the housing 21 in the direction of the outlet of the U. The path is, however, limited and remains inside the U-shaped wall. All of the mechanism then moves in the same way.

As in the version from figures 1 to 3, a bimetallic strip 13 is mounted rigid on the mobile contact 4. Its deformations allow, through contact with the shank 10, the pivoting of the trigger 5, and as a result the release of the end 3a of the link rod 3. Said pivoting can also be triggered by the striker 14 of the magnetic motor M.

The energy stored in the spring 16 during the preceding rotation, for locking, is then released, and the device returns to its initial position as illustrated in figures 5a and 5b.

According to an alternative appearing in figures 7a to 7c, the bimetallic strip 13 and the mobile contact 4 then only constitute a single piece 4' performing both fractions. In this case, for the bending of the strip to be able to take place under good conditions, the fixing 23 to the contact holders 17 must be done near the mobile contact 4' / fixed contact 12 bearing area.

The bending is done toward the operating lever 2, and the trigger 5 now comprises not a shank 10, but a protuberance 10' located at the level of the shaft of this lever, near the link rod 3 / ramp 11 bearing area.

As for the preceding versions with a bimetallic strip 13 fixed to the mobile contact 4, this configuration makes it possible to free oneself from all adjustments of the position of the bimetallic strip after assembly of the product.

Claims

193201/2 CLAIMS:

1. Lock mechanism for electrical apparatus of the circuit breaker type protecting lines and individuals, comprising at least one mobile contact intended to cooperate with one or more fixed contacts, the said mechanism being mobile between a locked position closing the line or lines controlled by the electrical apparatus and an unlocked position opening them, a member for operating it, making it possible to induce a position change of the mechanism and revealing any unlocking due to the occurrence on at least one line of electrical conditions incompatible with keeping it closed, the said operating member being connected via a rod to the said locking mechanism, which comprises: - at least one mobile contact supported by a contact holder and pivoting about a first axis between two positions, respectively bearing on and at a distance from a fixed contact, a force coming from one end of the rod being transmitted to the contact holder with a view to locking the mechanism; - a mobile trigger sending to the lock mechanism the information given by a magnetic or thermal measurement system with a view to unlocking it when it is in the position closing the contacts, the said trigger having a member for keeping the rod bearing against the contact holder in the locking phase and in the locked position; - means for returning the contact holder into the position opening each mobile contact at a distance from a fixed contact in the event of the rod being released, leading to the mechanism being unlocked; and - resilient means for making each mobile contact bear with pressure on a fixed contact in order to absorb the wear of the contact; characterised in that each mobile contact is rigidly connected to the contact holder, and the resilient means for making each mobile contact bear with pressure on a fixed contact are connected' to the contact holder by a connection which displaces the first pivoting axis with respect to the mobile contact/fixed contact bearing zone or zones as soon as the said bearing takes place. 193201/2

2. Lock mechanism according to the preceding claim, characterised in that it comprises means for guiding the displacement of the first pivoting axis.

3. Lock mechanism according to one of the preceding claims, characterised in that the said resilient means consist of a hairpin spring having a branch with a straight shape, one end of which is fixed to the housing of the electrical apparatus and the other end of which is bent perpendicularly to the said branch and provides the pivot for the rotation of the contact holder about the first axis by rotational fitting of the bent portion into a hole of the contact holder.

4. Lock mechanism according to the preceding claim, characterised in that the bent portion serves as a pivot for the trigger.

5. Lock mechanism according to one of the preceding claims, characterised in that the means for returning each mobile contact to a distance from a fixed contact consist of a hairpin spring with a branch one of the ends of which is fixed to the housing of the electrical apparatus, the said branch bearing on the contact holder and exerting there an action antagonistic to that of the rod.

6. Lock mechanism according to the preceding claim, characterised in that the free end of the said branch is bent substantially perpendicularly to the displacement plane of each mobile contact, the bent end portion being accommodated in a slideway formed in the contact holder.

7. Lock mechanism according to one of Claims 3 to 6, characterised in that the hairpin springs of the resilient means for making each mobile contact bear with pressure on a fixed contact, and of the means for returning each mobile contact to a distance from a fixed contact, respectively, are integral and are connected where they are fastened to the housing.

8. Lock mechanism according to the preceding claim, characterised in that the said springs are connected by an additional branch. 193201/2

9. Lock mechanism according to the preceding claim, characterised in that the branch has a straight shape extending substantially in the displacement direction of the free end of each mobile contact.

10. Lock mechanism according to one of Claims 1 and 2, characterised in that the resilient means for making each mobile contact bear resiliently on a fixed contact consist of a spring having a hairpin branch one end of which is connected to the housing of the electrical apparatus, the said branch being positioned at rest so as to be deformed by the contact holder being displaced during locking as soon as mobile contact/fixed contact bearing takes place, the contact holder being connected to the housing by a stud connection inserted into a socket or a groove allowing it to pivot about the first axis and guiding its displacement with respect to the mobile contact/fixed contact bearing zone.

11. Lock mechanism according to the preceding claim, characterised in that the said branch is positioned at rest so as to be deformed by the contact holder throughout its full movement, with a view to also acting as means for returning each mobile contact to a distance from a fixed contact.

12. Lock mechanism according to one of Claims 10 and 11 , characterised in that one of the ends of the hairpin branch is fixed to the housing.

13. Lock mechanism according to one of Claims 10 to 11 , characterised in that the hairpin branch constitutes one of the end branches of a coil spring, the coiled central portion of which encloses a stud and the other end branch of which bears permanently against a projection protruding from the housing.

14. Lock mechanism according to one any of Claims 10 to 13, characterised in that the contact holder comprises a journal inserted with a rotational and sliding fit into a socket of the housing.

15. Lock mechanism according to the preceding claim, characterised in that the said socket has walls erected in a U-shape so that the opening of the U faces in the direction of the mobile contact. 193201/2

16. Lock mechanism according to Claims 13 to 15, characterised in that the central coiled portion of the spring encloses the U-shaped socket.

17. Lock mechanism according to one of Claims 10 to 16, characterised in that the hairpin branch is driven by a pin protruding from the contact holder.

18. Lock mechanism according to one of Claims 14 to 17, characterised in that the trigger pivots about a stud coaxial with the mobile journal in the socket of the housing, the said stud protruding from the opposite face of the contact holder.

19. Lock mechanism according to any one of the preceding claims, characterised in that the contact holder comprises a ramp on which one of the ends of the rod bears, the said ramp cooperating with a catch of the trigger in order to keep the end of the rod bearing on the ramp in the locking phase and in the locked position.

20. Lock mechanism according to any one of the preceding claims, characterised in that the mobile contact(s) is or are integral with the contact holder.

21. Lock mechanism according to any one of the preceding claims, characterised in that a bimetallic strip is secured rigidly to the end of the mobile contact or one of the mobile contacts, opposite to its zone bearing against a fixed contact.

22. Lock mechanism according to any one of Claims 1 to 19, characterised in that the bimetallic strip is integral with a mobile contact.

23. Lock mechanism according to the preceding claim, characterised in that the bimetallic strip/mobile contact is secured to the contact holder in the vicinity of the mobile contact/fixed contact bearing zone and comprises a bending segment, the free end of which is arranged facing an outcrop of the trigger. 193201/2

24. Lock mechanism according to the preceding claim, characterised in that the outcrop of the trigger is placed in the vicinity of the member for keeping the rod bearing against the contact holder. For the Applicants, AND GOLLER