EP0951094B1 - Connection arrangement with insulation displacement connector - Google Patents

Description

The present invention relates to a self-stripping connection device for an electric cable consisting of a conductive core and an insulating sheath.

Such a device makes it possible to connect an electric cable to a conductive piece without the need to first strip one end of the electrical cable. The self-stripping connection device performs local stripping of the cable, for example by cutting the insulating sheath surrounding the conductive core, before making contact electric between the conductive core thus locally stripped and the part conductive.

A device having the characteristics of the preamble of claim 1 is described in document DE-A- 38 18 548.

European patent EP 0 247 360 discloses a device for self-stripping connection comprising a conductive connection piece which has a slot intended to receive the cable to be connected and which is mounted in an insulating housing having at least one opening allowing the introduction of the cable to be connected, as well as means allowing to strip the electric cable locally. In this device, the conductive piece has a core stripping and retaining slot of the cable. This slot, which is rectilinear, is longitudinally formed at the along a profile-shaped part which is obtained for example from of a flat blank, by stamping causing its cutting, folding and possibly localized thinning. The profiled part of the piece conductive has a hollow polygonal cross section which corresponds to a U whose free ends have been obliquely and also folded towards each other. The profiled part thus obtained has two folds end corresponding to the free ends obliquely and also folded up mentioned above. These two folds line the slit they delimit. A stripped mouth of the conductive part is formed at one end of the slot. It is obtained by oblique cutting symmetrical pleats bordering the slot at one of their ends. This oblique cut to obtain a flared mouth. The folding subsequent folds, relative to the walls which carry them creates an edge upper sufficient to start the sheath of the cables pushed in this mouth.

A special tool with a tip adapted to the shape of the conductive part is provided for introducing an electric cable in the conductive part. The insulating housing in which the conductive part is configured to fit the tool.

This connection device allows to realize, without stripping good electrical contact between the conductive part and the core conductive of a cable. The same conductive part can receive cables of different diameters within a determined diameter range.

One drawback of this connection device is that it requires the use of a specific tool. Without this tool it is very difficult to make a connection.

The conductive part of this connection device must be made of special materials to ensure both good stripping and good electrical contact and as it appears from the brief description above, the realization of this conductive part is quite complex. This makes this connection device cost-effective quite high.

The object of the present invention is therefore to propose a new self-stripping connection device. This device may preferably be used without a specific tool and will advantageously cost comes back low.

For this purpose, the self-stripping connection device for a electric cable consisting of a conductive core and an insulating sheath, which it proposes comprises a conductive connecting part which has a slot intended to receive the cable to be connected as well as means allowing to strip the electric cable locally.

According to the invention, the means for stripping locally the electric cable are made on a separate part of the conductive part and face the slot of the latter, and means movement are provided to move the cable from a position in which the bare cable is introduced into the device to a connection position in which the cable is located in the slot of the conductive part and in which the core of the cable is in electrical contact with the conductive part, the cable passing through the means making it possible to strip it locally during this movement.

In such a device, the stripping and connection are ensured by separate parts. This results in parts fairly simple to manufacture and can be made of materials "Ordinary".

This device can for example take place in a case insulation which has an opening allowing the introduction of the cable to Connect.

We can foresee various ways of acting on the means of displacement. We can thus consider a pusher such as for example described in patent FR-2 503 464 and which allows the introduction of a cable in a self-stripping jaw.

In a preferred embodiment, the conductive part of connection is mounted in an insulating box having at least one opening allowing the introduction of the cable to be connected, and the means of displacement comprise an elastic blade provided with means electric cable drive, the cable drive means facing the slot of the conductive part in the rest position of the elastic blade and facing the opening for introducing the cable into the insulating housing in the preloaded position of the elastic blade. For make a cable connection, all you have to do is prestress the blade elastic, introduce a cable to connect and release the elastic blade which then tends to return to its rest position, and which then drives with it the cable to the slot of the conductive part.

In this embodiment, an opening is advantageously provided in the insulating housing so as to allow the passage of a tool, such as a screwdriver blade, to prestress the blade elastic.

To achieve good guidance of the cable to be connected, the means preferably have a window in which can pass this cable. In some configurations, it may be sufficient to have a fork between the teeth of which the cable is placed.

In order to limit the number of parts of the device and thus facilitate its mounting, the means of movement and the means for strip the cable locally are advantageously made on the same room.

In this case, the device according to the invention has for example a part made in an elastic blade folded so that its two ends are substantially parallel to each other, one end being provided with two stripping lips and the other end being provided with cable drive means, such as example a window.

The elastic blade, on the side of the stripping lips, then rests preferably on the conductive part whose shape it follows, the lips stripping being inclined relative to the elastic blade so that the stripping part of these lips is well in front of the slot of the conductive part. We thus achieve a good positioning relative between the stripping lips and the conductive part. this is important so that the part exposed by the lips is well at level of the edges of the slot made in the conductive part, thus ensuring good contact between the stripped part and the conductive part.

To improve cable guidance during stripping, the cable drive means preferably include lugs guide substantially resuming the shape of the stripping lips.

To make a good electrical connection, the slot intended to receive the cable to be connected advantageously has an opening in the shape of a V and is extended, on the side of the point of the V, by two edges substantially parallel.

The present invention also relates to a terminal block of connection comprising an insulating box and a conductive part intended to be electrically connected to at least one electrical cable, terminal block which is provided with at least one self-stripping connection device as described above.

Figure 1 est une vue en perspective éclatée d'un bornier comportant deux dispositifs de connexion selon l'invention,

Figure 2 est une vue en perspective à échelle agrandie d'un ressort utilisé pour un dispositif de connexion selon l'invention,

Figure 3 est une vue de dessus d'une pièce conductrice, et

Figures 4 à 6 sont des vues de face du bornier de la figure 1 au cours de trois étapes de la connexion d'un câble.

In any case, the invention will be clearly understood with the aid of the description which follows, with reference to the appended schematic drawing, representing by way of nonlimiting example a preferred embodiment of a device according to the invention.

FIG. 1 is an exploded perspective view of a terminal block comprising two connection devices according to the invention,

FIG. 2 is a perspective view on an enlarged scale of a spring used for a connection device according to the invention,

Figure 3 is a top view of a conductive part, and

Figures 4 to 6 are front views of the terminal block of Figure 1 during three stages of the connection of a cable.

Figure 1 shows a terminal block fitted with two connection. This terminal block includes an insulating housing 2, two springs 4, as well than a conductive part 6.

The insulating housing 2 is a piece of synthetic material obtained for example by molding. The shape of its base is such that it can be fixed on standard fixing rails provided for this purpose. A housing 8 is provided for each spring 4 and each end of the conductive part 6. The upper face of the housing 2 has at each housing each time an opening 10 intended to receive a cable to be connected and an opening 12 intended to receive the blade of a screwdriver.

The conductive part 6 is shown in perspective on the Figure 1 and in top view in Figure 3. This part 6 can receive two electrical cables, one at each end. This piece conductive 6 is made from a metal blade, for example by copper.

At each end of the blade is made a slot 14 whose shape is visible in Figure 3. Each slot 14 is formed on the axis longitudinal median of the blade. At the end of the blade, the slot 14 has a V-shaped zone 16, the point of the V lying inside of the blade. The slot 14 is extended by a zone 18 in which the edges of the slot are substantially parallel. So each end of the conductive part is in the form of a fork, each of which arm has a certain elasticity, thanks to which the slot 14 can receive cables of different diameters while ensuring a excellent electrical contact.

The edges of the slot 14, both at the level of the V-shaped zone 16 that at the level of the zone 18 where the edges are parallel, are thinned. This thinning does not give the slit the cutting function but is made to fit the dimensions of the cutout that is made at level of the springs 4 and which will be described later.

The blade constituting the conductive part 6, once provided with each of its ends of a slot 14, is then folded so as to present at each of its ends a shape reminiscent of a collar swan, as we can see it for example in figure 1.

A tongue 20 is produced substantially in the middle of the part conductive to allow it to snap into the insulating housing 2.

Figure 2 shows in more detail a spring 4. Such a spring is formed from an elastic blade which can also be, for example, copper. This elastic blade is folded so as to form a spring. The width of the elastic blade used is substantially equal to the width of the blade used to make the conductive part 6. After folding, the two ends of the elastic blade are substantially parallel to each other the other. The central area of the elastic blade is folded so as to form an arc of a circle over a little more than 180 °. So the ends substantially parallel to the spring can move elastically one compared to each other. In the rest position, represented in FIG. 1 by example, the two ends of the elastic blade are offset one by compared to each other.

A first end of the elastic blade is folded so that you can come and take the swan neck shape from one end of the conductive part 6. As can be seen in FIGS. 4 to 6, each spring 4 comes to take place in its housing 8 on one end of the conductive part 6. The rounded central part of the spring 4 is placed at the base of the swan neck shape of one end of the conductive part 6. The spring 4 follows the upper face of the entire end in the form of gooseneck of the conductive part 6 and one end of this spring protrudes from the conductive part 6. The other end of the spring 4 comes place over this first end.

The end of the spring 4 which rests on the conductive part 6 is provided with a window 22. On the side of the end of the spring 4, this window 22 has a space 24 of sufficient size to receive a electric cable to connect. Inside window 22 is also two stripping lips 26. These lips 26 extend in a transverse direction relative to the elastic blade forming the spring 4 and are inclined opposite the other end of the spring. So these lips protrude from the elastic blade on the side of the conductive part 6 when the spring 4 is mounted on this conductive part 6 (FIGS. 4 to 6). The ends of the lips 26 are spaced apart from each other so to cut the insulating sheath of an electric cable which moves longitudinally relative to the elastic blade forming the spring 4 without damage the conductive core of this cable. Window 22 also shows a space 28 intended to receive a cable once it has been locally stripped by stripped lips 26.

The spring 4 is placed on the conductive part 6 so that that the stripping lips 26 abut against the end of the part conductive 6. The lips 26 are then in front of the slot 14. We ensures that the stripping area of the lips 26 is at the level of the thinned edges of the slot 14.

The other end of the spring 4 is also provided with a window 30. The latter is intended to receive an electric cable to connect and guide it to get it from space 24 of the first window 22 through the stripping lips 26 to bring it into space 28 for receiving a connected cable. Window 30 shows a substantially square shape with two longitudinal edges and two edges transverse to the elastic blade forming the spring 4. The two transverse edges are each provided with a lug 32. Each lug 32 extends towards the other end of the spring 4. These lugs resume substantially the shape of the stripping lips 26. There are thus lugs in V shape, each branch of the V being inclined substantially the same so that the lips 26 are inclined. In this way, the pins 32 allow good guidance of a cable to be connected to pass this cable between the stripping lips 26. The cable to be stripped and connected is then guided over the entire height of the lug and not just on the thickness of the elastic blade 4.

In the rest position of the spring 4, the window 30 is substantially above the space 28 of the window 22. In position window 30 is located above space 24 of the window 22. A tongue 34 is provided on each spring 4 in order to properly hold it on the conductive part 6. The tongue 34 can by example cooperate with the end of a slot 14 opposite the end having a V-shaped zone 16

Figure 4 shows a conductive part 6 and two springs 4 at rest in the insulating housing 2. The springs 4 and the shaped ends of the swan neck of the conductive part 6 are each placed in a housing 8. For proper positioning of these parts, stops 36 are provided inside the housings 8. There is thus a stop 36 placed inside the rounding of the spring 4 and another stop 36 allowing the correct positioning of one end of the conductive part 6.

The operation of a connection device according to the invention is described below with reference to FIGS. 4 to 6.

Figure 4 shows the two connection devices in position rest. Each space 24 intended to receive a cable to be connected is is located opposite an opening 10 of the housing. Windows 30 for the movement of a cable are erased relative to these openings 10. A first operation to perform to allow the connection of a cable is to prestress the spring 4. This is achieved by introducing the end of a tool, for example a screwdriver blade, through a opening 12 of the housing 2. The blade 38 of the screwdriver meets the spring 4 and is deflected towards a wall 40 of the housing 8. The shape of this wall 40 is such that by fully inserting the screwdriver into opening 12 until that the blade 38 of the screwdriver comes to the bottom of the housing 8, or more precisely comes into abutment against the conductive part 6, the spring either deformed so that the window 30 of the spring comes facing the space 24 of window 22 of the spring intended to receive a cable 42 to be connected.

Figure 5 shows the spring 4 in its pre-stressed position thanks to the action of the screwdriver blade 38 and also shows the end of a cable 42 which has been introduced through an opening 10 in the box 2. This end of cable 42 encounters no obstacle and first crosses the window 30 of the spring then the space 24 of the window 22 of this spring. The cable 42 consists of a conductive core and an insulating sheath.

The end of the cable 42 is now introduced into the case 2, the screwdriver blade 38 can be removed from this case 2. The spring 4 is then released. The energy stored by this spring during its deformation by the screwdriver blade is restored and used to pass the end of the cable 42 through the stripping lips 26 and to carry out the connection at the conductive part 6. The end of the cable 42 is guided over the entire height of a lug 32 when it passes between the lips 26. When passing between these lips, the insulating sheath of the cable is cut transversely to the axis of cable 42 thus exposing locally the conductive core of the cable. The shape of the lips 26 gives them a elasticity which allows them to adapt to the diameters of cables found within a predetermined diameter range. For each diameter of cable in this range, the lips 26 cut the insulating sheath so to locally expose the conductive core without, however, damaging it.

Once stripped, the end of the cable is brought into the slot 14 of the conductive part 6. The stripped area of the end of the cable 42 then slides at the level of the thinned edges of the slot 14. The end of the cable 42 is housed at the base of the zone 16 in the form of V. The spring is then not in its rest position. A constraint elastic is therefore still exerted on the cable 42 via including lug 32. This constraint promotes good contact electric between the conductive core of the cable 42 and the conductive part 6.

It goes without saying that the invention is not limited to the form of embodiment described above by way of nonlimiting example; she in on the contrary embraces all variants.

So for example, in the above embodiment, the means for moving the end of the cable to be connected and the means for locally stripping it are carried out on a same piece, the spring. As appears from the description above, we note that part of this spring is fixed and does not move during any the connection operation. It is therefore quite possible to have a fixed part at which the stripping of the end of the cable and a moving part to allow movement thereof.

The shapes of the various components of the device described are given by way of example and are not limiting. This is there preferred embodiments. So other forms can be chosen for the spring, for the stripped lips, for the window displacement, the conductive part, the slot thereof, etc.

Applying the connection device to another device electric than a terminal block is of course also possible. Such connection device can be used for connecting a cable to various types of electrical equipment. This device can also be used without the presence of an insulating box.

Claims (9)

1. Insulation displacement connection device for an electric cable, made up of a conductive core and an insulating sheath, comprising:

   a conductive connecting part (6) which has a slot (14) intended to receive the cable (42) to be connected, and

   means (26) enabling the electric cable to be stripped locally, and

   displacement means (30, 32) are provided to displace the cable from a position of introduction in which the unstripped cable (42) is introduced into the device to a connection position in which the cable is located in the slot (14) of the conductive part and in which the core of the cable is in electrical contact with the conductive part (6), the displacement means (30, 32) being designed to pass the cable through the means (26) enabling it to be stripped locally in the course of the displacement,

      characterised in that the means (26) enabling the electric cable to be stripped locally are realised on a part (4) that is separate from the conductive part (6) and facing the slot (14) of the latter.
2. Device according to Claim 1, characterised in that the displacement means (30) and the means (26) enabling the cable (42) to be stripped locally, are realised on the same part (4).
3. Device according to Claim 2, characterised in that the part (4) comprising the stripping means (26) and the displacement means (30) is realised in the form of a spring (4) obtained by folding a spring strip so that the two ends are substantially parallel to each other, one first end being provided with two lips (26) forming the stripping means and the other end being provided with cable transport means, such as a window (30), for example.
4. Device according to Claim 3, characterised in that the spring (4) at the side of the stripping lips (26) rests on the conductive part (6) whose shape it adopts, the stripping lips (26) being inclined with respect to the spring (4) in such a way that the stripping part of these lips (26) is located right opposite the slot (14) of the conductive part (6).
5. Device according to one of Claims 3 or 4, characterised in that the cable displacement means comprises guide lugs (32) substantially taking the shape of the stripping lips (26).
6. Device according to one of Claims 1 to 5, characterised in that the slot (14) intended to receive the cable to be connected has a V-shaped opening (16) and is extended at the side of the point of the V by two substantially parallel sides.
7. Device according to one of Claims 1 to 6, characterised in that the displacement means have a window (30) through which a cable (42) to be connected may pass.
8. Connecting terminal block comprising at least one insulating housing provided with at least one opening (10) intended to receive a cable to be connected, characterised in that it includes, in relation to each opening (10), at least one insulation displacement connection device according to one of the Claims 1 to 6.
9. Connecting terminal block according to one of Claims 8 or 9, characterised in that the insulating housing includes an opening (12) provided to allow the passage of a tool, such as a screwdriver blade (38), to pre-stress the spring strip (4).

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