EP0093056B1 - Electrical connection device - Google Patents

Description

The present invention relates to electrical connection devices and more specifically relates to such a device which allows the stripping of the insulation at the same time as the connection of the conductor.

The usual technique of connecting electrical conductors to contact or distribution elements such as those used in distribution or sub-distribution installations is done either by welding, or by screwing, or by winding the conductor around a terminal. square or rectangular section. All these methods use a stripping operation of the conductor carried out prior to the actual connection, which significantly increases the implementation time. In order to remedy this drawback, use has been made, especially for distribution installations, of connection means constituted by terminals known as "insulation displacement" or "self-stripping connection". Connection devices of this type comprise two lips, each having a cutting edge which cuts the insulation when the conductor is introduced between the lips. The conductor is then pinched between the sharp lips, which ensures both its mechanical retention and the electrical contact (See for example Be-A-648 254).

Such devices also have drawbacks due to the fact that the edges are in contact with each other in the absence of the conductor and that the latter must be force-fitted between the edges. Due to the pressure exerted by the two branches of the fork, the driver undergoes aggression which can lead to the appearance of a certain number of operating faults. During the introduction, the conductor undergoes a rolling aggravated by a planing, which has the main effect of reducing the section of the conductor at the connection point. The pressure unevenly distributed around the circumference of the conductor creates stresses in the metal and can cause incipient fractures detrimental to the good behavior of the connection, in particular in vibratory regime. If the conductor is a wired conductor, there is a risk of cutting a certain number of strands, thereby reducing the cross-section of the conductor and increasing the current density.

The object of the present invention is precisely to eliminate these drawbacks by proposing a connection device allowing the stripping of the conductor at the same time as the introduction of the latter without creating undue stresses at the connection point.

According to the main characteristic of the device which is the subject of the invention, it, of the type comprising at least one fork, the branches of which each have a sharp edge, the conductor to be connected being force-fitted and pinched between the sharp edges, is characterized by that each branch of the fork is extended by an arm and in that the device further comprises a part for inserting and extracting the conductor to be connected, the latter having a shape such that by spreading the ends of the arms during the insertion of the conductor it keeps them apart at a value such that the spacing of the cutting edges at the level of the conductor is slightly less than the diameter of the latter.

Thus, since the distance between the cutting edges of the fork is kept at a value slightly less than the diameter of the conductor, the latter is not laminated in the contact zone during insertion.

According to another characteristic of this device, each of the arms comprises, at its end opposite to the fork, a semi-circular boss.

• - deux plans inclinés aptes à écarter progressivement les extrémités des bras lorsque la pièce est introduite entre ces derniers,
• - deux plans parallèles se raccordant sur lesdits plans inclinés, et
• - deux concavités, se raccordant aux plans parallèles par deux autres plans inclinés et aptes à recevoir lesdits bossages afin d'assurer le maintien de la pièce d'insertion et d'extraction.

According to a preferred embodiment, the insertion and extraction part comprises two cheeks framing a central part, each of the cheeks having a notch making it possible to grasp the conductor to be connected and the central part having a shape as it has on the slice:

• - two inclined planes capable of gradually spreading the ends of the arms when the part is inserted between them,
• - two parallel planes connecting to said inclined planes, and
• - Two concavities, connecting to the parallel planes by two other inclined planes and able to receive said bosses in order to maintain the insertion and extraction part.

In an alternative embodiment, each cutting edge has, at one of its ends, a spoiler making it possible to cut the insulation surrounding the conductor to be connected.

Optionally, each cutting edge has a notch so as to define a housing for the conductor to be connected, said housing possibly being of square or circular section.

One can also have side by side several devices according to the invention, the branches of the different forks all being connected to a single current supply.

• - un corps d'outil,
• - un support relié par un premier ressort au corps d'outil et mobile en translation par rapport à ce dernier, et
• - un deuxième ressort fixé au support et apte à maintenir la pièce d'insertion et d'extraction dans un logement ménagé dans le support.

To operate the insertion and extraction part, a special tool is required. The latter essentially comprises:

• - a tool body,
• a support connected by a first spring to the tool body and movable in translation relative to the latter, and
• - A second spring fixed to the support and able to hold the insertion and extraction part in a housing provided in the support.

Advantageously, this tool further comprises a blade having a cutting edge, this blade being integral with the tool body and capable of sliding on one face of the support in order to cut the end of the conductor after the introduction of the latter.

Finally, the tool may comprise at one of its ends two bosses capable of cooperating with two notches formed in the insertion and extraction part in order to facilitate the extraction of the latter.

• - la figure 1 est une vue schématique en élévation d'un premier mode de réalisation du dispositif objet de l'invention montrant separement la pièce comportant la fourche et la pièce d'insertion et d'extraction,
• - la figure 2 est une vue schématique semblable à la figure 1 illustrant un deuxième mode de réalisation du dispositif,
• - la figure 3 est une vue schématique montrant la pièce d'insertion et d'extraction en place dans le dispositif illustré à la figure 1,
• - la figure 4 est une vue schématique semblable à la figure 3 et montrant la pièce d'insertion et d'extraction en place dans le dispositif illustré à la figure 2,
• - la figure 5 est une vue schématique en élévation montrant comment on peut rélier plusieurs dispositifs conformes à l'invention à une seule et même arrivée de courant,
• - la figure 6 est une vue schématique en élévation et partiellement en coupe montrant l'outil utilisé pour manipuler la pièce d'insertion et d'extraction, et
• - la figure 7 est une vue schématique en coupe suivant la ligne VII-VII de la figure 6.

The invention will appear better on reading the description which follows, given purely by way of illustration and in no way limiting, with reference to the appended drawings in which:

• FIG. 1 is a diagrammatic elevation view of a first embodiment of the device which is the subject of the invention, showing separately the part comprising the fork and the insertion and extraction part,
• FIG. 2 is a schematic view similar to FIG. 1 illustrating a second embodiment of the device,
• FIG. 3 is a schematic view showing the insertion and extraction part in place in the device illustrated in FIG. 1,
• FIG. 4 is a schematic view similar to FIG. 3 and showing the insertion and extraction part in place in the device illustrated in FIG. 2,
• FIG. 5 is a schematic elevation view showing how several devices according to the invention can be connected to a single current supply,
• FIG. 6 is a schematic view in elevation and partially in section showing the tool used to handle the insertion and extraction part, and
• - Figure 7 is a schematic sectional view along line VII-VII of Figure 6.

In Figure 1 we see the connecting part bearing the general reference 1 and whose central part 3 is a fork whose two branches 2 and 4 are limited by cutting edges 6 and 8 respectively defining a slot 9 into which is introduced the conductor to be connected. At the end of the latter, two inclined planes 13 and 15 are provided to facilitate centering of the conductor and its introduction into the slot 9 during insertion. The edges 6 and 8 are in contact with each other in the absence of a conductor. In order to increase the elasticity of the connecting piece 1, an opening 10 is made between the current inlet 12 and the fork 3. This arrangement has the effect of rejecting the stresses due to the pressure of the branches 2 and 4 on the conductor in the area 11 located between the current supply 12 and the opening 10. According to the invention, the branches 2 and 4 are extended by arms 14 and 16 respectively which terminate with semicircular bosses 18 and 20. The radius of each of these bosses must be equal to the radius of the largest conductor that the connecting element can accept.

• - deux plans inclinés 30 dont le rôle est d'écarter progressivement les bossages 18 et 20 des bras 14 et 16 afin d'assurer l'ouverture de la fente 9 préalablement à l'introduction du conducteur;
• - deux plans parallèles 32 servant à maintenir constant grâce aux bossages 18 et 20 l'écartement des bras 14 et 16 pendant l'introduction du conducteur dans la fente 9, dont l'écartement est ainsi réglé à une valeur légèrement inférieure au diamètre du conducteur, et
• - deux concavités 34 permettant de libérer les bossages 18 et 20 en fin de course lorsque le conducteur est en place et servant à maintenir la pièce d'insertion et d'extraction entre les bras 14 èt 16. Les plans parallèles 32 se raccordent aux concavités 34 par l'intermédiaire de deux plans inclinés 33. Il est bien entendu que la pièce d'insertion et d'extraction 21 reste en place une fois que le conducteur est raccordé et qu'il faut autant de pièces différentes que de diamètres de conducteur; en outre, la distance entre les plans parallèles 32 est telle que, une fois le conducteur placé en position définitive, il subsiste un jeu entre ces plans et l'intérieur des bras 14 et 16. On voit encore sur la figure 1 que la pièce d'insertion et d'extraction 21 peut comporter à son extrémité opposée à l'encoche 28 deux encoches 36 servant à l'extraction et dont le rôle sera précisé plus loin au cours de cette description.

Figure 1 shows, above the connecting piece 1, the insertion and extraction part used for the introduction of the conductor. The latter, bearing the general reference 21, consists of two cheeks 22 and 24 framing a central part 26. For greater clarity, the cheek 22 has been partially torn off in the drawing. Each of the cheeks 22 and 24 has at one end a notch 28 in which the conductor is placed before its introduction into the connection piece 1. In the figure, it can also be seen that the central piece 26 successively comprises from below, at the top:

• - Two inclined planes 30 whose role is to gradually move the bosses 18 and 20 of the arms 14 and 16 to ensure the opening of the slot 9 prior to the introduction of the conductor;
• - Two parallel planes 32 serving to maintain constant thanks to the bosses 18 and 20 the spacing of the arms 14 and 16 during the introduction of the conductor into the slot 9, the spacing of which is thus adjusted to a value slightly less than the diameter of the conductor , and
• - two concavities 34 making it possible to release the bosses 18 and 20 at the end of the race when the conductor is in place and serving to hold the insertion and extraction part between the arms 14 and 16. The parallel planes 32 are connected to the concavities 34 by means of two inclined planes 33. It is understood that the insertion and extraction part 21 remains in place once the conductor is connected and that as many different parts as there are conductor diameters are required. ; in addition, the distance between the parallel planes 32 is such that, once the conductor is placed in the final position, there remains a clearance between these planes and the interior of the arms 14 and 16. It can also be seen in FIG. 1 that the part insertion and extraction 21 may include at its end opposite the notch 28 two notches 36 used for extraction and whose role will be clarified later in this description.

FIG. 2 illustrates a second embodiment of the device which is the subject of the invention in which there is the connecting piece 1, the central part 3 of which is a fork composed of the two branches 2 and 4 extended by the arms 14 and 16 which end the bosses 18 and 20. However, in the case of FIG. 2, the edges 6 and 8 end in spoilers 38 and 40 respectively whose role is to strip the conductor and tear off the insulation therefrom at the time of introduction. In addition, in the middle of each of the edges 6 and 8 are provided notches 42 and 44 respectively serving to define a housing 45 of square section for the conductor to be connected. In this case, when the conductor is in place, the edges 6 and 8 are less spaced apart than in the case of FIG. 1 since the conductor is locked in the housing 45 whose side is slightly less than the diameter of this conductor.

Figures 3 and 4 show the device once the conductor is in place. For clarity, the cheek 22 of the insertion and extraction part 21 has not been shown in FIGS. 3 and 4. In FIG. 3, we see the bosses 18 and 20 of the arms 14 and 16 in place in the concavities 34 of the insertion and extraction part. We also see driver 46 pinched between the lips 6 and 8 of the slot 9 which remain separated from one another. It can also be seen that the conductor 46 is pressed against the upper part of the notch 28 formed in the cheek 22 of the part 21. The arms 14 and 16 move apart enough when the conductor is inserted so that the edges of the slot 9 are kept apart at a value such that the spacing of the lips 6 and 8 is only slightly less than the diameter of the conductor 46. This prevents rolling of the latter during its introduction into the slot and subsequently it is maintained efficiently while avoiding the constraints that could be detrimental to its mechanical strength in service.

Figure 4 is a view similar to Figure 3 showing the conductor in place in the connecting piece illustrated in Figure 2. The operating principle is the same but instead that it is the lips 6 and 8 of the slot 9 which cut the insulation when the conductor is inserted, this operation. is carried out by the spoilers 38 and 40. On the other hand, the lips 6 and 8 of the fork remain only a small amount apart, not shown in the figure, since the conductor is held in the housing of square section 45 This arrangement, although different from that of FIG. 3, offers the same advantages as regards the absence of mechanical stresses on the conductor 46 at the connection point.

FIG. 5 illustrates a variant, given by way of example, in which several devices in accordance with the invention are connected to a single current supply. The device is in the form of a single large connecting piece 48 in which are formed two openings 10a and 10b extended, on the side opposite to the current supply 12, by two slots 49 and 51 respectively. The part 48 comprises, at its end opposite to the current inlet 12, two lateral arms 52 and 54 terminated by semicircular bosses 56 and 58 and a central arm 60 terminated by two semicircular bosses 62 and 64. On therefore sees that the left part of the part 48 is similar to the connecting part illustrated in FIG. 1 while the right part is similar to the connecting part illustrated in FIG. 2.

The operation of the device illustrated in FIG. 5 is identical to the operation of the device illustrated in the preceding figures. It is understood that, if the part illustrated in this figure allows the connection of two conductors on a single current inlet 12, it is conceivable to connect any number of conductors to a single current inlet using a such device. It suffices to give the different arms such as 52, 60 and 54 the elasticity necessary for them to move apart under the action of the insertion and extraction part 21, for example by providing additional slots in the arms such as 60 which have two bosses such as 62 and 64.

In order to facilitate the installation and extraction of the part 21, a special tool is necessary. In Figure 6, we see that this tool, bearing the general reference 65, consists essentially of a tool body 66 having at one of its ends two bosses 67 intended to cooperate with the notches 36 of the part d 'insertion 21 (see Figure 1) to facilitate the extraction thereof. At the other end of the tool body is a support 70 connected by a spring 71 to the tool body and movable in translation relative to the latter. At the end of the support 70 opposite to that on which the spring 71 is fixed is a housing 72 capable of receiving the insertion and extraction part. A leaf spring 74 serves to hold the latter in the housing 72. At the end of the support 70 furthest from the tool body is a notch 75 for receiving the cable to be connected. We also see in Figures 6 and 7 a blade 76 secured to the tool body 66 and able to slide on one face of the support 72 when the latter moves relative to the tool body 66 during compression or relaxation of the spring 71. This movement is allowed by an opening 77 formed in the blade 76 and through which a retaining screw 78 passes. At the end of the blade 76 closest to the notch 75 of the support 70 is a ridge cutting 79 for cutting the end of the cable after the introduction thereof into the connecting piece.

The installation of the insertion and extraction part using the tool 65 takes place in the following manner: first the insertion and extraction part is introduced into the housing 72 where it is held by the spring 74, its position being such that the notch 28 of the cheeks 22 and 24 corresponds to the notch 75 of the support 70. The conductor is then introduced into these notches. The operator then places the assembly above the connecting piece and begins to introduce the insertion and extraction part between the bosses 18 and 20. The introduction of the insertion and extraction part takes place done in the manner which has been described above but when the latter reaches the end of the travel (blocking by the bosses 18 and 20 which penetrate into the concavities 34), the operator continues to push on the tool. The part 21 being held in the housing 72, the support 70 remains fixed but the tool body 66 continues to descend, which has the effect of compressing the spring 71. On the other hand, the blade 76, which is integral with the tool body and movable relative to the support 70, begins to descend and passes in front of the notches 28 and 75. The edge 79 then cuts the protruding end of the conductor. When the tool is removed, the spring 71 relaxes and the insertion and extraction part is automatically released from the housing 72 since it is blocked by the bosses 18 and 20. To extract the insertion part and d extraction, just present the other end of the tool, the bosses 67 making it possible to grip the part 21 via the notches 36 provided at the end of the latter.

The device according to the invention has many advantages, the first of which is to lengthen the life of the conductor since it prevents planing of the latter during introduction and the stresses which are exerted on it are much more weak than with the devices of the prior art. In addition, this device is very simple and very easy to implement since, even if it requires as many different insertion and extraction parts as diameters of conductor to be connected, their manufacture is inexpensive due to their simplicity. Finally, the device can be applied to any connection installation and in particular to distribution or sub-distribution installations since it is possible to connect several devices according to the invention to a single current supply.

Claims (12)

1. Electrical connection device for a cylindrical conductor, this device comprising at least one fork (3), the arms (2,4) of which each have a cutting edge (6, 8), the conductor to be connected being inserted, with force, and gripped between the cutting edges, each arm (2, 4) of the fork (3) being extended by an arm (14, 16), characterized in that the device also composes a part (21) for inserting and removing the conductor to be connected, the said part having a shape such that is able to separate the ends of the arms (14, 16) when the conductor is inserted and keep them separated at a distance such that the distance between the cutting edges than the diameter of the latter.

2. Device according to Claim 1, characterized in that each of the arms (14, 16) has a semi-circular boss (18, 20) at its end opposite the fork (3).

3. Device according to Claim 1, characterized in that the said insertion and removal part (21) comprises two cheeks (22, 24) enclosing a central part (26), each of the cheeks (22, 24) having a notch (28) for gripping the conductor to be connected and the central part having a shape such that it has on the cross-section:

- two inclined surfaces (30) designed to gradually separate the ends of the arms (14, 16) when the part (21) is inserted between the latter;

- two parallel surfaces (32) which are connected to the said inclined surfaces (30); and

- two concave portions (34) which are connected to the parallel surfaces (32) by inclined surfaces (33) and are designed to receive the said bosses (18, 20).

4. Device according to Claim 1, characterized in that each cutting edge (6, 8) has, at one of its ends, a beak-like portion (38, 40) for cutting the insulating material surrounding the conductor to be connected.

5. Device according to Claim 1, characterized in that each cutting edge (6, 8) has a notch (42,44) so

- as to define a seat (45) for the conductor to be connected.

6. Device according to Claim 5, characterized in that the said seat (45) has a square cross-section.

7. Device according to Claim 5, characterized in that the said seat (45) has a circular cross-section.

8. Device according to any one of Claims 1 to 7, characterized in that it comprises at least two forks, the arms of which are connected to a single and same source of current.

9. Device accord to Claim 1, characterized in that it comprises a tool (65) used for manipulating the insertion and removal part (21).

10. Device according to Claim 9, characterized in that the tool (65) comprises:

- a tool body (66),

- a support (70) connected by a first spring (71) to the tool body (66) and movable in translation relative to the latter, and

- a second spring (74) fixed to the support (70) and desinged to keep the insertion and removal part (21) in a seat (72) provided in the support (70).

11. Device according to Claim 10, characterized in that the tool (65) also comprises a blade (76) having a cutting edge (79), this blade (76) being integral with the tool body (66) and being able to slide on a support surface (70) so as to cut the end of the cable when the latter is inserted.

12. Device according to Claim 9, characterized in that the tool (65) has, at one of its ends, two bosses (67) designed to co-operate with two notches (36) provided in the insertion and removal part (21) so as to facilitate removal of the latter.

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