GB2369254A

GB2369254A - Connection device for two or more electrical cables.

Info

Publication number: GB2369254A
Application number: GB0127403A
Authority: GB
Inventors: Ambroise Mercier-Gallay; Sebastien Cote
Original assignee: Entrelec SAS
Current assignee: ABB France SAS
Priority date: 2000-11-15
Filing date: 2001-11-15
Publication date: 2002-05-22
Also published as: FR2816764B1; DE10155924A1; GB0127403D0; FR2816764A1

Abstract

The device for connecting at least two electrical cables to an interconnection plate comprises clamping means actuated by a single operating member in order to simultaneously press the two conducting ends of the two electrical cables against two opposed faces of the plate.

Description

The invention relates to the technical field of connection devices intended to provide electrical connection between at least one electrical cable and an interconnection plate by clamping the conduction end of the cable against the plate.

In the above field, it is known to use devices in which the connection is made by means of a screw, by clamping the conducting end of the cable against the interconnection plate.

Such devices are generally satisfactory when they are used to connect only a single electrical cable to the plate.

However, it has been found that such connection devices cannot satisfactorily ensure electrical connection and mechanical immobilization of the end of several cables on or against the same interconnection plate. This drawback of the devices according to the prior art is further accentuated when the cables to be connected have different diameters.

To remedy this drawback, the prior art has therefore recommended the use of as many connection devices as there are cables to be connected so as to ensure optimum clamping of each of the cables.

However, this solution does not appear to be completely satisfactory insofar as it increases the manufacturing cost of the connection device and requires the operator, charged with connecting the various cables to the device, to clamp or actuate as many operating members as there are cables to be connected.

There is therefore a need for a connection device which has a lower manufacturing cost and is simpler to implement by the user charged with connecting the cable or cables.

To satisfy this need, Patent Applications DE 3 314 919 and DE 4 102 581 have proposed a device for connecting two electrical cables to an interconnection plate. The device proposed comprises clamping means actuated by a single operating member in order to simultaneously press, against two opposed faces of the plate, the two conducting ends of the two electrical cables.

The clamping means are then made in the form of a clamping yoke which can move with respect to the plate and has: - a branch, called the clamping branch, lying on one side of the plate in order to define, with one face of the plate, a connection housing for the conducting end of a first electrical cable and a branch, called the operating branch, lying on the opposite side of the plate and having a tapped bore provided, as operating member, with a locking screw, the bearing end of which is oriented towards the plate in order to define, with the other face of the plate, a connection housing for the conducting end of a second electrical cable.

Although such a device allows two cables to be connected together, it does, however, have the drawback of not allowing three cables to be connected together while offering sufficient guarantees that the cables are effectively immobilized and that the electrical connection is of high quality.

There therefore seems to be a need to have a device which allows three cables to be connected together while offering good guarantees of mechanical retention and high-quality electrical connections.

To achieve this objective, the invention relates to a device for connecting at least two electrical cables to an interconnection plate of the type comprising

clamping means actuated by a single operating member in order to simultaneously press, against two opposed faces of the plate, the two conducting ends of the two electrical cables, characterized in that it comprises, as clamping means: - a clamping yoke which can move with respect to the plate and has, on the one hand, a branch called the clamping branch, lying on one side of the plate in order to define, with one face of the plate, a connection housing for the conducting end of a first electrical cable, and, on the other hand, a branch, called the operating branch, lying on the opposite side of the plate and having a tapped bore provided, as operating member, with a locking screw, the bearing end of which is oriented towards the plate for the conducting end of the second electrical cable; and an intermediate plate which is linked, upon slackening, to the locking screw and is placed between the end of the locking screw and the interconnection plate in order to define two connection housings for the end of a second electrical cable and of a third electrical cable, respectively.

Use of the intermediate plate, combined with the clamping yoke and the interconnection plate, makes it possible to define three separate housings for the ends of the three cables.

Thus, the invention advantageously makes it possible to ensure optimum clamping of each of the cables independently of the dimensions thereof. In addition, the device according to the invention also makes it possible to ensure optimum clamping of a single cable against one or other of the sides of the plate in the absence of another cable to be connected.

According to another feature of the invention, the connection device includes a clamping plate linked translationally to the locking screw and interposed between the bearing end of the locking screw and the intermediate plate. Use of the clamping plate makes it possible to ensure better distribution of the pressure exerted by the screw on the conducting end of the cable placed in the corresponding housing.

The invention also relates to a terminal block and to an electrical apparatus incorporating at least one connection device according to the invention.

Various other features of the invention will become apparent from the description given in conjunction with the drawings below, which present non-limiting illustrative examples of the invention.

Figure 1 is a cross section illustrating one embodiment of a connection device according to the invention, incorporated into a terminal block.

Figure 2 is a cross section on the line II-II in Figure 1.

Figure 3 is a cross section similar to Figure 1, showing another embodiment of a connection device according to the invention.

As is apparent from Figures 1 and 2, the connection device according to the invention, denoted in its entirety by the reference 1, comprises clamping means 2 actuated by a single operating member 3 making it possible to simultaneously press the conducting ends of two electrical cables 5 and 6 against the two opposed faces of an interconnection plate 4.

According to the preferred embodiment illustrated, the connection device comprises, as clamping means 2,

firstly a clamping yoke 8 which can move with respect to the plate 4. The clamping yoke 8 has, in a preferred but not strictly necessary manner, on the one hand, a clamping branch 9 which lies on one side of the plate 4 and, on the other hand, an operating branch 10 lying on the opposite side of the plate while being joined to the clamping branch 9 by two webs 11 located on each side of the plate. According to the example illustrated, the clamping branch 9 and the operating branch 10 are approximately parallel to the large faces of the interconnection plate 4 and the webs 11 of the yoke which join them, lie along the interconnection plate 4, being approximately perpendicular to the large faces of the latter. Thus, the yoke has, in longitudinal cross section, an approximately rectangular shape which gives the yoke good mechanical strength. Of course, the yoke could be any other shape suitable for its function, such as for example a Ushape.

The operating branch 10 has a tapped bore 12 provided, as operating member with a locking screw, the bearing end 13 of which is oriented towards the plate 4. Thus, the clamping branch 9 and the bearing end 13 define, together with each corresponding large face of the plate 4, a housing 15 and 16 for the conducting end of a respective cable 5 and 6.

It should be noted that the interconnection plate is, of course, made of an electrically conducting material, whereas the clamping yoke 8 and the locking screw 3 are made of a material having mechanical strength properties suitable for their use, as will become apparent below. Preferably, the yoke 8 is made of an electrically conducting material.

The connection device according to the invention, and made in this way, may be used in the following manner.

When it is desired to connect two electrical cables 5 and 6 to the interconnection plate 4, the conducting ends of these cables are each placed, on each side of the interconnection plate 4, in a connection housing 15 or 16. Next, the operating member or screw 3 is actuated, by the operator charged with making the connection, in the direction of screwing up the screw 3 into the tapped bore 12. This screwing movement therefore causes the clamping branch 9 to move towards the corresponding face of the interconnection plate 4, as indicated by the arrow Fi whereas the bearing end of the locking screw 3 moves towards the opposite face of

the interconnection plate, as indicated by the arrow F2.

Thus, the conducting ends of the electrical cables 5 and 6 are pressed simultaneously against the two opposed faces of the interconnection plate 4. Given the independent nature of the connection housings 15 and 16, the clamping produced by means of the locking screw 3 is independent of the respective dimensions of the cables 5 and 6 so that the device according to the invention ensures optimum clamping of the conducting ends of the cables 5 and 6 irrespective of the dimensions thereof. In addition, the connection device according to the invention makes it possible to ensure effective connection of a single cable to the interconnection plate 4, even in the absence of another cable in one or other of the connection housings 15 or 16.

According to a preferred feature of the invention, in order to ensure optimum clamping of the electrical cable 6 located in the connection housing 16 defined by the bearing end 13 of the locking screw and the corresponding face of the interconnection plate, the invention makes provision to interpose, between the interconnection plate and the bearing end 13, a clamping plate 17 which is linked translationally to the locking screw 3. This translational link guarantees that the clamping plate 17 follows the movements of the

locking screw 3 perfectly, during clamping or slackening of the cable or cables located in the connection housings 15 or 16.

In the example illustrated, the clamping plate 17 is formed by one of the branches of a U-shaped clip 20.

This branch 17 bears against the end in contact with the bearing end 13, whereas the other branch 22 has a bore in which the head 23 of the locking screw 3 engages, which screw also has a flange 24 against which the branch 22 bears. Thus, the clip 20, and more particularly the clamping plate 17 formed by one of its branches, follows all the movements of the locking screw 3. The clip 20 is made of an insulating material or preferably an electrically conducting material.

The connection device 1 according to the invention is more particularly, but not exclusively, provided so as to be used in a terminal block, as illustrated in Figure 1, which comprises an insulating casing 30 in which at least one connection chamber 31 is made. The interconnection plate 4 then lies in the connection chamber 31 and the connection device 1 is fitted into the latter so that the clamping means 2, formed by the clip 8 and actuated by the operating member consisting of the locking screw 3, can move translationally in a direction perpendicular to the large faces of the interconnection plate 4. Thus, the connection device 1 mounted so as to float in the casing 30 makes it possible to ensure that one or more electrical cables are clamped against the interconnection plate, as explained above.

Of course, the casing 30 furthermore includes at least one passage 33 towards the connection chamber 31 in order to place the conducting ends of the two cables 5 and 6 into relationship with the interconnection plate 4. The casing also includes an access port 34 for a

screwdriver for example, so as to operate the head 23 of the locking screw 3. Of course, such a terminal block may be used autonomously or may form an integral part of an electrical apparatus.

The connection device according to the invention can be used to electrically connect more than two cables to the interconnection plate 4. However, according to a preferred feature, the invention recommends defining as many connection housings as there will be cables to be connected to the interconnection plate 4.

Thus, Figure 3 illustrates another embodiment of the invention in which three cables 5,6 and 40 can be connected to the interconnection plate 4. In order to define a third connection housing 42, the invention provides the use of an intermediate plate 43 which is placed between the end 13 of the locking screw and the interconnection plate in order to define two connection housings 16 and 42 for the ends of the two electrical cables. The intermediate plate 43 is then linked to the locking screw 3, at least upon slackening. Preferably, this linkage upon slackening is provided by a leg 44 of the intermediate plate 43. This leg 44 is intended to cooperate with that face of the clamping plate 17 on the opposite side from the intermediate plate 43. As Figure 3 shows, the operating leg 44 is then placed between the clamping plate 17 and the operating branch 10 of the clamping yoke 8. When the screw 3 has been tightened, the plate 17 bears against the end of the cable 40 in the direction of the arrow F3. The cable 40 then bears on the intermediate plate 43, which presses the end of the cable 6 against the corresponding face of the interconnection plate 4. Simultaneously with this movement, the end of the cable 5 is pressed by the clamping branch 9 against the opposite face of the interconnection plate 4.

On the other hand, when slackening the screw, the clamping plate 17 pulls on the operating leg 44, so as, upon slackening, to return the intermediate plate 43 and thus release the end of the cable 6. Moreover, slackening the screw 3 also releases the ends of the cables 5 and 40.

To ensure that the various cables 5,6 and 40 are properly clamped and electrically connected to the interconnection plate 4, provision may be made, on the intermediate plate 43, on the clamping branch 9 of the yoke 8 and on one or other or both faces of the interconnection plate 4, one or more protruding elements 45. It should be noted that the protruding elements 45 may also fulfil a stripping function, by perforating the protective sheath possibly surrounding the end of the electrical cables 5,6 and 40.

The invention is not limited to the above examples, since various modifications may be made thereto without departing from its scope.

Claims

1. Device for connecting at least two electrical cables (5,6) to an interconnection plate (4) of the type comprising clamping means (2) actuated by a single operating member (3) in order to simultaneously press the two conducting ends of the two electrical cables against two opposed faces of the plate (4), characterized in that it comprises, as clamping means (2) : a clamping yoke (8) which can move with respect to the plate and has, on the one hand, a branch (9) called the clamping branch, lying on one side of the plate in order to define, with one face of the plate, a connection housing (15) for the conducting end of a first electrical cable (5), and, on the other hand, a branch (10), called the operating branch, lying on the opposite side of the plate and having a tapped bore (12) provided, as operating member (3), with a locking screw, the bearing end (13) of which is oriented towards the plate (4) for the conducting end of the second electrical cable (6); and - an intermediate plate (43) which is linked, upon slackening, to the locking screw and is placed between the end (13) of the locking screw (3) and the interconnection plate (4) in order to define two connection housings (16,42) for the end of a second electrical cable and of a third electrical cable (40), respectively.

2. Connection device according to Claim 1, characterized in that it includes a clamping plate (17), linked translationally to the locking screw (3) and interposed between the bearing end (13) of the screw (3) and the intermediate plate (4).

3. Connection device according to Claim 1 or 2, characterized in that the intermediate plate (43)

has an operating leg (44) intended, upon slackening, to co-operate with that face of the clamping plate (17) which is located on the opposite side from the intermediate plate (43).

4. Connection device according to one of Claims 1 to 3, characterized in that the interconnection plate (4) includes, on one of its faces, a protruding element (45) intended to improve the clamping of the end of an electrical cable and the electrical connection between this end and the plate.

5. Connection device according to one of Claims 1 to 4, characterized in that the intermediate plate (43) or the clamping plate (17) includes, on at least one of its faces, a protruding element (45) intended to improve the clamping of the end of an electrical cable and the electrical connection between this end and the plate.

6. Terminal block for at least two electrical cables, characterized in that it comprises: an insulating casing (30); at least one connection chamber (31) made in the casing ;

an interconnection plate (4) lying in the connection chamber (31) ; a device (1) according to one of Claims 1 to 5, for connecting at least two cables (5, 6) to the interconnection plate (4); at least one passage (33) towards the connection chamber (31) in order to place the conducting ends of the two electrical cables (5,6) in relationship with the interconnection plate (4) and the connection device (1); and an access port (34) for access to the operating member (3) of the connection device (1).

7. Electrical apparatus comprising a terminal block according to Claim 6.