EP1194943B1 - Fuse-holder clip and fuse-holder equipped with same - Google Patents

Abstract

A fuse-holder clip including two lugs designed to define a space for receiving a fuse cartridge with circular cross-section. The lugs are folded along lines parallel to a central axis of the cartridge when the cartridge is placed in the clip such that each lug forms two electrical and mechanical lines of contact for engaging and supporting the cartridge with the two lines being globally parallel to the axis.

Description

The invention relates to a jaw for a fuse holder and a fuse holder equipped with at least one such jaw. Such a jaw is described for example in US-A-4176906.

In the field of plant protection electric, it is known to use fusible cartridges cylindrical, that is to say of which the two terminals or capsules are cylindrical, these terminals or capsules being intended to be received in jaws, themselves connected to power lines. Jaws of the devices known include rounded parts intended for to marry globally part of the circumference of the cylindrical capsule of a fuse. The contact between the jaws and the capsule is thus surface.

Moreover, to resist a repulsion effort created during an overcurrent, between the capsule of a fuse and the jaw in which it is received, the standards provide that the force of support or pressure of a jaw on a capsule of fuse must be in the range of several tens of Newton. For example, in the case of a fuse whose terminals have a diameter of 27 mm, the supporting force must be greater or equal to 45 Newton. If such a force is useful when the fuse is in place in the jaw, she opposes the setting in place and extracting the fuse from the jaw, such so that the efforts that an operator must make to these occasions are intense to the point that wrong maneuvers can be generated. So, it is not uncommon that when extract a fuse from a known jaw, the effort to exert, who must overcome the friction generated at the surfaces of contact, is so important that it induces a tearing violent fuse "jumps" from its slot in the fuse holder, and falls to the ground.

In addition, in known devices, contacts between the cylindrical capsule of a fuse and the two legs of a jaws can be concentrated in two divided areas of both sides of the capsule, so that the sizing jaws should be provided considering that the current of breakdown is divided in two at the level of each jaw. This imposes the constitution of thick jaws, therefore rigid, and induces additional difficulties when setting up or extracting a fuse.

In the devices of the prior art, it is common to plan to maneuver several fuses in parallel, a rocker being provided for this maneuver. take in account the important efforts to be made on the fuses during these maneuvers, the rocker must be able to support a very important effort which leads to its over-sizing, this which increases all the cost of a fuse holder.

It is these disadvantages that are particularly remedy the invention, by proposing a jaw of the aforementioned type wherein a circular section fuse capsule is effectively maintained and which allows for an introduction and easy extraction of such a capsule.

In this spirit, the invention relates to a jaw for fuse holder comprising two legs intended to define between they a space of reception of a capsule of fuse with section circular, characterized in that these tabs are folded according to parallel directions to a central axis of the capsule in place in the jaw, so that they form each two lines of electrical contact and mechanical support on the radial surface of this capsule, these two lines being overall parallel to this axis.

Thanks to the invention, the contact between each of the legs of the jaw and the capsule of a fuse is exerted according to two lines, so that the friction forces that must be defeated when setting up or extracting of a fuse are generated only between these lines and the outer radial surface of the capsule. They are therefore less important than in the case of surface contacts such obtained with the devices of the state of the art. A the capsule in place in the jaw, this one is effectively maintained through the cooperation of the four lines contact formed by the two jaws. These four lines of contact also result in a division into four of the breakdown current, or even three in case of imperfection geometric result in a capsule support on three of the four lines of contact formed by the two jaws. The maximum current flowing in each of the contact areas is thus equal to a quarter or a third of the breakdown current of the fuse, which makes it possible to dimension the jaws based on this value, and not according half of the breakdown current as in the devices of the state of the art. The invention also allows appropriately dimension the rockers intended for the joint operation of several fuses, since the efforts that they have to bear are significantly less important than in the devices of the state of the art.

• Les traces des deux lignes de contact électrique et d'appui mécanique dans un plan perpendiculaire à la surface radiale de la capsule sont comprises dans un secteur, centré sur la trace de cet axe central dans ce plan, d'angle au sommet inférieur à 30°. On peut, en particulier, prévoir que cet angle au sommet est compris entre 20 et 28°, de préférence de l'ordre de 24°. Grâce à cette construction, les deux lignes de contact électrique et d'appui mécanique formées sur chaque patte sont relativement proches l'une de l'autre et le caractère linéique du contact peut être garanti dans la mesure où la surface radiale externe de la capsule ne peut pas pénétrer entre ces lignes au point de générer un contact surfacique.
• Chaque patte comprend, entre les lignes de contact, une zone déformée vers l'extérieur par rapport à un plan principal de la patte. Cette construction permet de réaliser les deux lignes de contact de façon particulièrement simple. La zone déformée comprend avantageusement deux surfaces inclinées par rapport au plan principal de chaque patte et l'une par rapport à l'autre. Dans ce cas, l'angle au sommet de cette zone déformée, qui est défini par les deux surfaces inclinées, est avantageusement compris entre 80 et 100°, de préférence de l'ordre de 90°.
• Les extrémités des pattes sont divergentes par rapport à un axe médian de la mâchoire. On peut prévoir que l'angle de divergence de ces extrémités est compris entre 16 et 24°, de préférence de l'ordre de 20°. Grâce à cette disposition, les extrémités des pattes forment un cône de glissement lors de l'introduction de la capsule du fusible dans la mâchoire, d'où une progressivité de l'effort que doit exercer l'opérateur pour la mise en place de la capsule, cette progressivité étant ressentie par l'utilisateur comme un confort supplémentaire. De plus, les extrémités évasées assistent le mouvement d'extraction de la cartouche fusible car elles exercent sur la capsule un effort élastique d'éjection par rapport à la mâchoire. Les pattes de la mâchoire de l'invention travaillent ainsi à la fois en flexion et en friction lors des mouvements de mise en place et d'extraction du fusible.
• Un ressort externe de maintien est prévu en appui sur les pattes de la mâchoire au niveau des zones déformées vers l'extérieur, par rapport à un plan principal de chaque patte, ces zones étant définies entre les lignes de contact. Ce ressort extérieur assure l'effort de serrage axial de la capsule de fusible lorsque celle-ci est en place dans la mâchoire.

According to advantageous aspects of the invention, the jaw incorporates one or more of the following features:

• The traces of the two lines of electrical contact and mechanical support in a plane perpendicular to the radial surface of the capsule are included in a sector, centered on the trace of this central axis in this plane, with an apex angle less than 30 °. In particular, it is possible to provide that this apex angle is between 20 and 28 °, preferably of the order of 24 °. Thanks to this construction, the two lines of electrical contact and mechanical support formed on each leg are relatively close to each other and the linear nature of the contact can be guaranteed insofar as the outer radial surface of the capsule can not penetrate between these lines to the point of generating a surface contact.
• Each tab comprises, between the contact lines, a zone deformed outwardly with respect to a main plane of the tab. This construction makes it possible to make the two contact lines in a particularly simple manner. The deformed zone advantageously comprises two surfaces inclined with respect to the main plane of each leg and one relative to the other. In this case, the apex angle of this deformed zone, which is defined by the two inclined surfaces, is advantageously between 80 and 100 °, preferably of the order of 90 °.
• The ends of the tabs are divergent with respect to a median axis of the jaw. It can be provided that the angle of divergence of these ends is between 16 and 24 °, preferably of the order of 20 °. With this arrangement, the ends of the tabs form a sliding cone during the introduction of the fuse capsule into the jaw, resulting in a progressive effort required by the operator for the implementation of the capsule, this progressivity being felt by the user as additional comfort. In addition, the flared ends assist the extraction movement of the fuse cartridge because they exert on the capsule an elastic force of ejection relative to the jaw. The legs of the jaw of the invention thus work both flexibly and frictionally during the movements of introduction and extraction of the fuse.
• An external holding spring is provided in abutment on the tabs of the jaw at the outwardly deformed areas, with respect to a main plane of each tab, these areas being defined between the nips. This outer spring ensures the axial clamping force of the fuse cap when it is in place in the jaw.

The invention also relates to an equipped fuse holder at least one jaw as previously described. Such fuse holder is easier to handle for a user while remaining reliable and of moderate cost price.

• la figure 1 est une vue en perspective d'une mâchoire conforme à l'invention ;
• la figure 2 est une vue de face de la mâchoire de la figure 1 au repos ;
• la figure 3 est une vue analogue à la figure 2 alors qu'une capsule est dans une première étape d'introduction dans la mâchoire ;
• la figure 4 est une vue analogue à la figure 2 alors que la capsule est dans une seconde étape d'introduction dans la mâchoire ;
• la figure 5 est une vue analogue à la figure 2 alors que la capsule est en place dans la mâchoire et
• la figure 6 est une vue partielle en perspective d'un porte-fusible conforme à l'invention.

The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of an embodiment of a jaw for fuse holder and a fuse holder according to its principle, given purely by way of example and with reference to the appended drawings in which:

• Figure 1 is a perspective view of a jaw according to the invention;
• Figure 2 is a front view of the jaw of Figure 1 at rest;
• Figure 3 is a view similar to Figure 2 while a capsule is in a first step of introduction into the jaw;
• Figure 4 is a view similar to Figure 2 while the capsule is in a second step of introduction into the jaw;
• FIG. 5 is a view similar to FIG. 2 while the capsule is in place in the jaw and
• Figure 6 is a partial perspective view of a fuse holder according to the invention.

The jaw 1 visible in FIGS. 1 to 6 comprises a base 2 extending by a tongue 3 to be connected to an electrical conductor 4 schematized by a center line and belonging to a line to be connected to a fuse 5 shown in phantom lines in Figures 1 to 5 and in lines full in Figure 6.

The base 2 is extended by two legs 21 and 22 which extend in a direction generally perpendicular to the base 2 and define between them a receiving space E of a cylindrical capsule 6 forming one of the end terminals fuse 5.

X _{1 is} the axis of symmetry of the capsule 6, this axis X ₁ being disposed in a median plane P of the space E when the capsule 6 is in place in the jaw 1, as shown in Figures 1 and 5. We denote by D ₆ the diameter of the capsule 6.

P _{21 is} a plane generally parallel to the plane P which constitutes a central plane of the lug 21 in its lower part. In the same way, we note P ₂₂ an equivalent plan for the tab 22.

According to the invention, the tab 21 is folded outwardly of the plane P ₂₁ with respect to the space E, about an axis A ₂₁ generally parallel to the axis X ₁ in the configuration of FIGS. From the axis A ₂₁ , the lug 21 forms a zone 21 b which is deformed outwards with respect to the plane P ₂₁ and which is concave in the direction of the space E because it is folded around a second axis C ₂₁ parallel to the axis A ₂₁ , and in an opposite direction. The tab 21 is also folded along an axis D ₂₁ parallel to the axis A ₂₁ and approximately in the plane P ₂₁ . Respectively 21 and 21 is noted e f surfaces defined between the axes A ₂₁ and C ₂₁ on the one hand, C ₂₁ and D ₂₁ on the other. Area 21b is formed of surfaces 21e and 21f .

Beyond the line 21 d , the tab 21 is extended by an end 21 g folded outwardly of the plane P ₂₁ .

Α is the angle at the top of the zone 21 b in the plane of Figures 2 to 5 and β the angle of inclination outwardly of the end 21 g of the lug 21, that is to say say its angle of divergence with respect to the plane P.

In the same way, the tab 22 is folded about axes A ₂₂ , C ₂₂ and D ₂₂ parallel to the axes A ₂₁ , C ₂₁ and D ₂₁ and comprises two surfaces 22 e and 22 f extending outside the plane P ₂₂ with respect to the space E and defining an outwardly deformed zone 22b between the axes A ₂₂ and D ₂₂ . As previously, the end 22 g of the tab 22 is folded outwards with respect to the plane P ₂₂ .

As is more particularly apparent from FIG. 5, when the capsule 6 is in place in the jaw 1, it is formed on the inner surface of the lugs 21 and 22 facing the space E and respectively at the axes A ₂₁ , D _21, a ₂₂ and D _22, four lines 21 a, 21 d, 22 a and 22 d of electrical contact and mechanical support between the legs 21 and 22 and the outer radial surface 6a of the cartridge 6, the lines of contact being generally parallel to the axis X ₁ .

Thus, and as is more particularly apparent from FIG. 5, the elastic bearing force of the jaw 1 on the surface 6 a is decomposed into four elementary forces F A ₂₁ , F _{D 21} , F A ₂₂ and F _{D 22} , these forces being globally directed to the X axis ₁ .

In practice, the lines 21a and 22a are formed by the generatrices of the inner faces of the lugs 21 and 22 at the pins A ₂₁ and A _22, these generatrices being defined at the join respectively between the inner face of each leg 21 or 22 in its portion 21c or 22c parallel to the plane P ₂₁ or P ₂₂ and the surface 21 e or 22 e . The lines 21 d and 22 d are formed by the generatrices of the inner faces of the lugs 21 and 22 at the axes D ₂₁ and D ₂₂ , these generatrices being defined respectively at the junction of the inner faces of the surfaces 21 f and 21 g or 22 f and 22 g .

In the plane of FIGS 2 to 5, the traces of the lines 21 a, 22 a, 21 d and 22 d are included in two angular sectors Δ ₂₁ and Δ ₂₂ in which there is the apex angle γ. The angle γ is of the order of 24 °, this value giving satisfactory results over a range of between 20 and 28 °.

This relatively low angle value γ corresponds to fact that the legs 21 and 22 are relatively little deformed in flexion when setting up and extracting the capsule 6. Efforts to overcome therefore retain a value relatively low, resulting in ease of use when setting up and fuse extraction 5.

With this arrangement, the contact lines 21 a, 22 a, 21 d and 22 d are sufficiently close to each other so that the surface 6a of the cartridge 6 is not likely to penetrate into areas 21b and 22 b to the point that surface contact occurs between the surface 6a and the inner surface of the areas 21 b and 22 b. In other words, the geometry of the tabs 21 and 22 ensures a double linear contact between these tabs and the capsule 6, including in case of slight dimensional defects of the jaw 1 or the capsule 6.

Thanks to the invention, the maximum current capable of transiting between the fuse 5 and the conductor 4 is divided into four at lines 21 a, 22 a, 21 d and 22 d. If geometrical default of the capsule 6, one of the aforementioned lines may not be in contact with the surface 6a, maintaining however being properly ensured thanks to the three other contact line defining, with the cartridge 6, a isostatic system. In all cases, it can be considered that the maximum current flowing on a line of contact between the surface 6a and a lug 21 or 22 is at most equal to one-third or one quarter of the fuse breakdown current, so that the thickness e of the legs 21 and 22 can be defined according to this parameter.

The introduction of the cartridge 6 in the jaw 2 is shown in Figures 3 and 4. At the beginning of the introduction, the outer radial surface 6a of the jaw 6 rests against the inner surface of ends 21 g and 22 g of the tabs 21 and 22. The thrust force exerted by a user is represented by the arrow F ₂ and is reported at the level of the contact zone between the surface 6 a and the ends 21 g and 22 g , as represented by the arrows F ₃ . These forces F ₃ have the effect of bending the tabs 21 and 22, as represented by the arrows F ₄ , while a friction force represented by the arrow F ₅ is generated at the surfaces in contact, 6 a , 21 g and 22 g in the configuration of Figure 3. The tabs 21 and 22 therefore work in both flexion and friction. In the configuration of FIG. 4, the effort F ₂ that the user must exert is essentially intended to move the lugs 21 and 22 by flexion, as represented by the arrows F ₄ , because the friction force is substantially reduced by the fact that essentially linear contact which then takes place between the lines 21 d and 22 d and the surface 6 a . This effort is not much greater than the effort that must be exerted in the configuration of Figure 3, even as the legs 21 and 22 are more bent.

Is reached at the position of Figure 5 where the forces F _{A21, D21} F, F _A22 and F _D22 exerted along the four lines 21a, 21c, 22a and 22c are directed towards the axis X ₁ and border the two sectors Δ ₂₁ and Δ ₂₂ with angles at the apex γ in the plane of FIG. 5. The capsule 6 is then firmly immobilized, all the more so since a holding spring 7 can be used, as shown in FIG. Figure 6.

Note d ₁ the distance between the lines 21 a and 22 a on the one hand, 21 d and 22 d on the other hand, in the configuration of Figure 5. Given the relatively low value of the angle γ, the distance d ₁ is slightly less than the diameter D ₆ , which corresponds to the fact that the tabs 21 and 22 are only slightly deformed in flexion during the placement of the capsule 6.

When it is appropriate to extract the fuse 5, it suffices to exert on it a force in the opposite direction of the force F _2, contact between the surface 6a and the lines 21a and 22a are then removed , so that only the linear contacts at the lines 21 d and 22 d remain, a movement that can be generated without too much effort, so that the fuse must not undergo any efforts or accelerations that may result in its fall outside the fuse holder.

As shown in FIG. 6, two jaws 1 and 1 'can be used in a fuse holder being arranged, in opposition, at the level of the two capsules 6 and 6' of a fuse 5. Each jaw 1 or 1 'is connected by a leg 3 or 3 'to a conductor 4 or 4'. Each jaw is associated with a spring 7 or 7 ', in the form of a clamp, provided to exert on the legs 21 and 22 a pinching force F ₅ of the capsules 6 or 6'. The force F ₅ may be relatively large, especially so that the fuse holder complies with the standards in force, without interfering with the installation and extraction of the fuse, because this effort F ₅ is transmitted to the capsules 6 and 6 'by the line contact achieved in the lines 21 a, 22 a, 21 d and 22 d.

In the configuration of Figure 6, the movement of introduction and extraction of the fuse 5 in the jaws 1 is a pivotal movement about a transverse axis Y, this movement being represented by the arrow F ₆ . Given the direction of this movement and to limit the contact forces, the ends 21 g and 22 g each comprise an edge at an angle 21 h , 22 h .

Claims (10)

1. Fuse holder clip comprising two lugs which are intended to define between them a space for receiving a fuse capsule with a circular section, characterised in that said lugs (21, 22) are folded according to the directions (A₂₁, C₂₁, D₂₁, A₂₂, C₂₂, D₂₂) parallel to a central axis (X₁) of said capsule (6) in place in said clip (1), such that they each form two lines (21a, 21d, 22a, 22d) of electrical contact and mechanical support on a radial surface (6a) of said capsule, said two lines being overall parallel to said axis.
2. Clip according to claim 1, characterised in that the traces of said two lines (21a, 21d, 22a, 22d) of electrical contact and of mechanical support in a plane perpendicular to said radial surface (6a) of said capsule are included in a sector which is centred on the trace of said central axis (X₁) in this plane and has an angle at the top (γ) less than 30°.
3. Clip according to claim 2, characterised in that said angle at the top (γ) is between 20 and 28°, preferably of the order of 24°.
4. Clip according to one of the preceding claims, characterised in that each lug (21, 22) comprises, between said lines of contact (21a, 21d, 22a, 22d), a zone (21b, 22b) which is deformed towards the exterior with respect to a main plane (P₂₁, P₂₂) of said lug.
5. Clip according to claim 4, characterised in that said deformed zone (21b, 22b) comprises two surfaces (21e, 21f, 22e, 22f) which are inclined with respect to said plane (P₂₁, P₂₂) and with respect to each other.
6. Clip according to claim 5, characterised in that the angle at the top (α) of said deformed zone (21b, 22b) defined by said two inclined surfaces (21e, 21f, 22e, 22f) is between 80 and 100°, preferably of the order of 90°.
7. Clip according to one of the preceding claims, characterised in that the ends (21g, 22g) of said lugs (21, 22) are divergent with respect to a median plane (P) of said clip (1).
8. Clip according to claim 7, characterised in that the angle of divergence (β) of said ends (21g, 22g) is between 16 and 24°, preferably of the order of 20°.
9. Clip according to one of the preceding claims, characterised in that it is associated with an external retaining spring (7) which abuts on said lugs (21, 22) at the level of the zones (21b, 22b) which are deformed towards the exterior, with respect to a main plane (P₂₁, P₂₂) of each lug, said zones being defined between said lines of contact (21a, 21d, 22a, 22d).
10. Fuse holder equipped with at least one clip (1) according to one of the preceding claims.

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