Electricity: circuit makers and breakers – Toggle mechanisms
Reexamination Certificate
2001-02-13
2002-12-10
Luebke, Renee (Department: 2833)
Electricity: circuit makers and breakers
Toggle mechanisms
C200S425000
Reexamination Certificate
active
06492607
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a mechanism for the rapid closure of electrical contacts on modular electrical apparatuses, particularly circuit-breakers and differential circuit-breakers. The mechanism is equally suitable for use with single pole, neutral phase, and multi-polar apparatuses.
BACKGROUND OF THE INVENTION
Rapid electrical contact closure mechanisms, such as is disclosed in European Patent EP-0224396, have previously been known. That mechanism principally includes two components, which pivot with a hand operated lever and movable electrical contacts respectively. The components move along paths, which coincide during a fraction of the combined rotation of the components. These components are provided to cooperate in order to lock the movable electrical contact at a distance from the fixed electrical contact during a portion of rotation, before rapid release at the end of the phase of cooperation, and subsequent closure of the contacts at a speed which is independent of the speed applied to the hand lever.
In the system described in EP-0224396, the combined rotational movement between the hand operating lever and the sub-assembly carrying the movable electrical contact causes an individual rotation of each component in the same direction of rotation. Their axes being offset, the components situated one at the periphery of the hand lever and the other at the edge of the sub-assembly carrying the movable electrical contact, advance in opposite directions in the zone in which their trajectories interfere.
To diagram and visualize their movements, the example is used of two circular paths meeting along two lines developing in opposite directions. In this case, the paths intersect twice, in the zone of first contact and in the zone of disengagement leaving the interference zone.
The system disclosed in patent EP-0224396 is based on such a configuration, which has the consequence that when the components intersect, their disengagement results naturally from the opposite directions of the paths of the components.
SUMMARY OF THE INVENTION
The mechanism of the present invention comprises at least one movable electrical contact provided to cooperate with at least one fixed electrical contact, the movable electrical contact being arranged pivotably relative to a contact support, their relative positioning at rest being determined by the action of a contact spring which maintains a correct pressure in order to keep the electrical contacts in a closed position, even when they are worn.
The contact support itself moves with a rotational motion permitting positioning of the movable electrical contact alternatively against and at a distance from the fixed electrical contact, in particular by manual action on a hand operating lever pivoting between two stable positions and causing the rotation of the contact support through a conventional mechanical toggle system.
In the present invention, a control lever, which may be manually actuated, and a movable electrical contact are given a rotational movement in opposite directions, which causes the intersection of the respective paths of two components which converge and move in the same direction.
In this configuration, it is not easy to produce a second intersection of the paths with a view to disengaging the components from one another, due to the limited space which typically exists in the casing of a modular electrical apparatus and because each component is on the path of the other. This is also the result of the existence of an angular travel of given length for the control lever and also for the contacts.
The rapid closure mechanism of the invention meets these particular constraints and consequently has a specific configuration, which is suited to the above-mentioned, particularly kinetic, constraints.
The components of the invention participating in the rapid closure function consist of a cam driven by the hand operating lever, arranged free to rotate through a limited range relative to the latter, and of a finger, which is fixedly attached to the movable electrical contact, the positioning of which relative to the cam and the movable electrical contact respectively is such that the finger and the cam enter into contact when the fixed and movable electrical contacts are spaced by a predetermined residual distance, the cam having an outer surface along which the finger slides when the rotation of the hand lever takes place, of such length and shape that the finger remains locked in rotation during a fraction of rotation of the hand lever less than its residual travel to reach its stable position of closure of the contacts.
The contact support for its part continues its travel, while the contact spring accumulates energy, which it releases rapidly when the cam/finger contact stops, in the final portion of the travel of the hand lever. The cam can then pursue its rotation relative to the hand lever, the angular range being limited by a stop of the hand lever, an elastic element being interposed between the cam and this stop.
Functionally, the relative positioning of the finger and of the cam, their respective shapes and, in particular, the length of the outer surface of the cam, only permit locking of the movable electrical contact or contacts to be obtained.
The possibility for the cam of a residual rotation relative to the hand lever in particular permits absorption of contact wear and also plays a role in their opening.
The same is true of the elastic element which is interposed between the stop and the cam when the latter comes into the proximity of the former, permitting retraction of the cam on opening of the contacts, and preventing failure of rapid closure on their closure.
More precisely, the cam includes a barrel of hollow cylindrical form turning about a central spindle fitted to the center of a drum provided with a radial lever and forming the hand lever, the drum including an aperture arranged substantially opposite the lever and permitting the passage of a radial projection of the cam extending from the barrel, the free end of which broadens and includes an outer surface coaxial with the cylindrical surface of the barrel, the edges of the aperture parallel with the generatrix of the drum forming the stops between which the cam is free to rotate.
This cam, quite simply added to an already existing hand lever and lock structure, can in the same manner be removed if the rapid closure function is not required.
Preferably, the elastic element consists of a leg fixed to the outer surface of the barrel and diverging progressively from it in the direction of its free end, and placed on the side of the cam entering firstly into contact with the finger on closure of the contacts.
This configuration does indeed render the final portion of relative rotation of the cam relatively to the hand operating lever, in the direction of closure of the contacts, elastic. As will be seen in more detail below, this proves necessary to retract the cam on opening of the contacts.
In this case, in fact, as mentioned above, the end of the finger is in the theoretical trajectory assumed by the cam on the opening movement and is able to form an obstacle to the return movement. If this possibility of retraction did not exist, there would therefore be a forced engagement between these two components, risking damaging the system, or at least causing with time wear incompatible with the function to be fulfilled.
Again preferably, the finger, which is fixedly attached to the movable electrical contact is situated between the latter and the hand operating lever and is formed by overmolding the conductive movable electrical contact with an insulating material.
When the rapid closure mechanism is used in a neutral phase product, there is not therefore an insulation problem in the zone of rapid closure, managed in the circumstances by a single cam, and which imposes a certain closeness between the mobile equipments.
In such a neutral phase apparatus, the cam is identical to that of a single phase product, the uter surface of the cam
Bruckert Didier
Diebold Francis
Duez Olivier
Sitz Thierry
Abelman, Frayne & Schawab
Hager Electro
Luebke Renee
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