DE2042692A1 - Device for making cable branches - Google Patents

Description

SOCIETE INDUSTRIELLE DE CONSTRUCTION D'APPAREILS ET DE MATERIEL ELECTRIQUES

Device for making cable branches

Around branches on distribution networks with pre-assembled insulated cables perform, especially on networks that supply consumer connections, there are several types of connections, in particular from a piece of existing branch connection, which is the subject of French patent specification 1,195,439 of May 19, 1959.

One of the essential characteristics common to all such compounds is that the main cable must be stripped to an exact length for attachment. On this part of the Cable, whose metallic core is stripped, the branch cable is connected by means of the connection.

The stripping of the main cable, which is in a pre-assembled bundle of including multiple cables is tedious and therefore costly and inconvenient for the following reasons:

1. The stripping, which depends on the dimensions of the connection , must be carried out to an exact length. In fact for the Safe Clear leeches countries that the entire branch under a

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insulating protective cap is brought. It is therefore important that the The length of the stripped part of the cable does not exceed the dimensions of the protective cap.

2. Despite the use of special clamping tools, it is inconvenient to strip one of the conductors that is difficult to get out of the bundle lets out, of which he is a part. To do this, used mostly wooden wedges, which after the introduction into the bundle on both sides of the point to be stripped, a relative clearance of the Cable that you want to work on. Obviously, the use of such methods is not always without serious dangers

necessary for insulation, as it should be emphasized that these cables are only one have a single thin insulating layer.

3. The preliminary stripping of the insulation from the main cable can be carried out in spite of the aforementioned inconveniences, taking precautionary measures on a network without electrical voltage. In view of the dangers that arise, it becomes practically impracticable when the network is in operation, ie when it is under electrical voltage . This disadvantage constitutes a very serious disadvantage if the more and more desired continuity of the electrical energy supply is required in order to carry out interventions in the network as much as necessary without interrupting the power supply.

There is a connection that is hardly available in stores that can be used without

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Previous stripping allows branches to be attached to above-ground, preassembled, insulated cable harnesses, and their use is spreading very quickly, especially in the case of cables with a conductive core made of aluminum. This connection consists of two massive pieces, each drawn from a profile and which are put together by a dovetail-shaped hook means. The inner part, which is in the shape of a cradle, has two cutting projections, i

which rest on the metallic core of the cable by clamping - i penetrate the insulation. A hole provided in this lower part accommodates the branch cable, which is fastened there with the aid of a simple pointed screw.

The upper part has, whose flat end having substantially the shape of an inverted V, the basic transmits a ^{n H} Threaded bolt, which is nothing but an ordinary screw has a rather large and a fairly deep slot. As previously stated, "

this part with the lower part by dovetail guide rails put together.

The function of the facility is simple. Passing the stripped end of the branch cable in the intended channel for this purpose in the lower part of the compound a and pulls on the clamping screw. So you put the two parts of the connection on the unstripped main cable,

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Holding them by sliding them on the dovetail, the milling screw that first comes into contact with the insulation is screwed tight, furthermore it is destroyed by the combined action of the pressure of the screw and its rotation, whereby the cutting edge of the slot of the screw act like two rotating knives and separate shavings from the insulation, then the edges of the screw slot produce the same effect on the metallic core of the cable, which thus comes into contact with the milling screw, i.e. with the upper part of the Connection, then with its lower part and finally with the branch cable. During the period of clamping penetrate the two cutting edges which are transverse to the main cable, and which are located at the lower part of the connection, in order to obtain a firm grip on the metallic core of the cable the insulation, thus the untimely release of the connection avoided which could result in closing as a result of softening due to heating of the insulating jacket .

This connection has serious disadvantages :

Since it consists of solid parts, it does not have the elasticity of the clamping, which is essential to ensure long-term contact.

As a result of the curvature of the cable, which can be locally strong because of it

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consists of small diameter wires, the effect of the pressure of the screw arranged in one plane on the strongly convex metallic core can only result in a "contact line" ¹ or possibly a small "contact area" if the milling screw is actuated sufficiently while taking the fact into account continues that this activity, which produces metal chips, locally weakens the cross-section of the metal core, so that for cables that are exposed to mechanical tension, there are consequences in electrical terms as well as for the mechanical operation.

The path of the current in the connection is unnecessarily long and contains in particular a secondary contact in the guide rails of the arrangement, which it must traverse.

The insulating chips collect and contaminate the slot of the screw milling machine. Moreover, if the cutting system is not perfect, the insulation will be eaten away so that burrs or lift-offs of insulating material can remain between the screw and the metallic core , the contact zone of which is uncontrollably reduced.

Finally, attachment is not very convenient because the connection does not consist of one piece.

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The object of the invention is to provide a one-piece To create a connection which does not have the disadvantages of the previous connection and which allows a branch to be made in a convenient manner on an insulated cable without stripping the cable.

To this end, the invention proposes a connection for connecting electrical conductors, which is characterized in that it consists of a cutting element which is arranged so that it at least partially surrounds a cable covered with an insulating layer and a stripped part of a branch conductor, furthermore from an intermediate piece of electrically conductive material which is arranged so that it can be brought between the cable and the part of the conductor and which is provided with knives on the slot which is arranged opposite the cable, furthermore by means around the to clamp the following elements against each other, namely the cable, the intermediate piece and the part of the conductor and in order to allow the knife to penetrate the insulating layer in the course of the clamping and to bring it into contact with the metallic core of the cable.

According to the invention, the electrical contact with the core of the insulated cable arises from the fact that the knives of the intermediate piece penetrate the insulating layer. There is no removal of the insulating material, and it should be noted that this is the case

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helps to maintain the clamping pressure, provided that for it Care is taken that the flow of the material is avoided.

The invention also proposes measures with the aim of to counteract this flow.

According to one embodiment, such a connection, which is made from electrically conductive materials, includes a bracket which is adapted to engage over a cable to be connected, and a locking means for the bracket which is adapted to bridge between its forms a pressure medium with sharp knives, which are intended to rest through the insulation on the metallic core of the cable, wherein the pressure medium lies on the closure means with the help of a pressure screw, furthermore an intermediate piece that is slidably connected to the bracket, one of which Surface is adapted to the shape of the base of the bracket and the other surface is provided with tall and strong blades designed to make electrical contact with the metallic core of the cable, after having penetrated the insulation under the action of the pressure that is transmitted by the pressure medium, and finally Means for attaching the stripped end of a branch cable to the bracket .

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According to an exportation. is ^ άηη locking device rotatable • mounted on one arm of the bracket and has means that allow it to automatically lock rrsit the -. *, other arm.

According to an application example, the base part of the bracket is provided with a through hole which the abisc .be ¹ ".e 5; ends of the branch cable can measure, - by clamping this between the base part and the intermediate piece. ih the pressure screw can be held.

Such a connection is particularly easy to make: after the stripped end of the branch cable has been inserted through the hole in the base of the cable and the wires spread out on both sides of the hole, the intermediate piece is brought into its place in the bracket, then the insulated and non-stripped mains

cable into the bracket, it is then sufficient to bring the locking means into its locked position in order to then put the pressure medium into operation, which is formed by the pressure screw and its jaw, which is attached to the end of the screw to rotate freely. Under the action of the pressure, the knives of the intermediate piece penetrate the insulation and thus establish a direct electrical contact between the metallic core of the cable and the expanded wires of the branch cable , which are fixed

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wedged between the intermediate piece and the lower part of the bracket are. It should better be noted that with the help of suitable insulating tools, the connection can be made very conveniently without to break the current in the main conductor .. In fact, the conductor will energized only in the last phase of installation, when the pressure screw is clamped at the moment when the knives of the pressure jaw or those of the intermediate piece come into contact with the metallic core of the cable.

According to a preferred embodiment of the invention, the bracket is produced by cutting out of metallic and drawn sheet metal. This design is simple and robust, although the bracket should be light. Its arms have a certain elasticity, which is favorable for performing the automatic locking of the closure means. Indeed, the locking means of the locking means advantageously comprise hooks provided at the free end of the locking means, the hooks being adapted to engage between the elastic arms of the bracket with windows provided on the locking arm. It should also be noted that the curvatures of the bracket in the lower part are designed so that they always leave a certain play between the arms of the bracket and the cables to be clamped. One receives in

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Moment of clamping an elastic deformation of these curvatures, which results in a remarkable ability of the connection, the clamping force and thus the quality of the contact made on the Maintain duration.

The invention is described below with reference to the accompanying drawings. Show it:

Fig. 1 is a front elevational view in the longitudinal direction of the connection;

2 shows a section of the closed connection in the direction of the width;

Figure 3 is a rear elevation;

Figure 4 is a widthwise elevation with the joint open and the adapter removed;

Fig. 5 is a perspective view of the intermediate piece; FIG. 6 shows a modification of FIG. 5;

Fig. 7 is a section in the width direction of another embodiment the compound of the invention;

8 shows the last-mentioned embodiment as a front elevation in the longitudinal direction.

In the following explanation, the word "cable" is intended to mean a conductor with a full core or a conductor whose core is stranded or made up of

»
reren metallic cores is composed, denote.

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According to the embodiment selected and shown in FIGS. 1-5, a connection according to the invention consists of a bracket 5 which is cut out and pressed from a metal sheet, such as bronze, and whose base part has a hole 21 through which the stripped end of the branch cable is inserted can be, whose veins 22 are spread out and regularly distributed on both sides of the hole. The base part of the bracket 5 has curvatures 26 which always have a certain amount of play in relation to the parts to be clamped in such a way that significant elastic deformation of the curved rings is possible for the clamp. The bracket 5 has two eyelets 6 on one of the arms, each of which has an axis bore 7. Two rectangular windows 8 are provided on the other arm. The eyelets c serve to accommodate the axis of rotation 12 of a pawl 10, which consists of a profile piece made of brass or bronze. This pawl 10 contains two hooks 9 on the side opposite the hinge axis 12, which hooks are arranged so that they automatically come into engagement with the windows 8 when closing thanks to the elasticity of the arms of the bracket 5. In practice , the rotatable attachment of the pawl 10 causes an engagement - the axis 12 comes into engagement with the bore 11 of the pawl, while this axis 12 can rotate freely in the bore 7 of the eyelets 6 . Advantageously , the axis consists of a brass or bronze wire. The pawl 10 also includes a threaded hole 13,

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which comes into engagement with a hexagonal screw 14. One jaw 15, which consists of a profile piece made of brass or bronze, has sharp knives on its lower surface and along its entire length 17 on. It has a milled hole 16 in the middle which engages with the end of the screw 14, this end with play on the The jaw is attached so that the screw 14 is free in the jaw can turn. The upper part of the jaw has bevels 27, which when the screw 14 is screwed all the way up in the operating pawl 10, to the abut complementary slopes 25 of the recess which is provided over the entire length of the lower surface of the pawl 10 such that the jaw 15 can no longer rotate in relation to the pawl 10 and thus automatically when the pawl 10 is closed is right in relation to the arms of the bracket 5.

The intermediate piece 18, which is made from a profile piece made of brass or bronze, has a lower shape which is adapted to the shape of the base part of the bracket such that when the connection is clamped, the spread out wires 22 of the branch cable are pinched, even if they have one have a very small diameter. The upper surface contains knife 19 over its entire length , which are sufficiently high and very sharp . The intermediate piece 18 is somewhat larger than the width of the arms such that retaining claws 20 can be provided at the ends of the piece, which the intermediate piece 18 on the bracket 5

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so that it can slide along the arms of the bracket.

The connection is used as follows: With the pawl 10 open (position of FIG. 4) and the intermediate piece 18 lifted up, the stripped end of the branch cable is inserted through the hole 21 into the interior of the bracket 5, then on both sides of the hole 21 the Cores 22 of the cable, brings the intermediate piece 18 in place by inserting it through the upper part of the arms of the bracket 15 and sliding it until it touches the cores 22 of the branch cable. The mains cable 24 is then brought inside the bracket 5 without stripping it. This is easy to do, although the cable can be part of a bundle made up of several cables, since the very thin arm of the connection 5 can easily be inserted between the cables of the Bundle can be introduced. The pawl 10 is allowed to rotate which, with its rotation, entrains the screw 14, which is completely unscrewed, and the jaw 15, which cannot rotate in the bevels 25 until the hooks 9 of the pawl 10 come into engagement with the windows by themselves, with the pawl 10 is automatically locked with the bracket 5. So far, all of the operations described have been carried out without touching the insulation of the power cord and consequently without the risk of electric shock. It is now sufficient to screw in the pressure screw 14 , preferably with the aid of an insulating wrench.

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The knife 17 of the pressure jaw 15 penetrate the insulation 24 of the Power cable 23 and are independent of the plastic property of the jacket 24 on the metallic core of the cable. Penetrate at the same time the knife 19 of the intermediate piece 18 also the insulating jacket and clamp the wires 22 of the branch cable, which between the Intermediate piece 18 and the base of the bracket 5 lie. As soon as the knives 19 touch the metallic core of the cable, electrical contact is established between the mains cable 23 and the branch cable with the aid of the intermediate piece 18.

As can be seen from FIGS. 2 and 5, the knives 19 are straight and arranged parallel to the axis of the power cord, the cutting edges being on a cylindrical surface, the diameter of which is substantially equal to the diameter of the core of the cable, so that the contact with the cable can be made in several lines can.

Likewise, the knives 17 of the pressure jaw advantageously provide the power cord parallel straight edges.

In the variant of FIG. 6, the two lateral knives 19 of the intermediate piece 18 are straight cutting edges, while the two middle knives 19 * represent a toothed cutting edge with triangular notches 32, between which cutting parts 33 remain, the one

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ORIGINAL INSPECTED

Sequence of quasi-punctiform contact zones with insulation covered soul of the cable. With an aluminum core, these point-like contacts make it easier to destroy the non-conductive ones Aluminum oxide layer that forms on the surface of the aluminum. They also favor the penetration of the very thin but resistance ~ capable tape, which is often placed between the conductive metallic core and the insulating jacket.

On the other hand, in the same figure is the inner surface of the intermediate piece 18 with longitudinal grooves 34 low in height, but with straight or toothed Provide cutting edges, which are intended to destroy the aluminum oxide skin of the veins of the branch conductor, if the core of the conductor is made of aluminum.

Appropriately, each of the contact zones 33 extends over one Length from 0.5 to 1.5 mm.

The embodiment of FIGS. 7 and 8 is particularly suitable for branches on insulated underground cables and even more so on cables to which conductors with a solid core in the form of a section of a circle are to be connected, which are often formed by a solid profile made of aluminum that has the shape a section of a circle, instead of conductors consisting of veins that spread out on the base of the bracket .

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This embodiment also facilitates the execution of tangential Branches where the branch cable exits parallel to the main cable and reducing the size of the metallic casing allow, in which the branch arrangement is included, this contains as many connections as phases plus those of the neutral conductor.

In FIGS. 7 and 8, in which the elements which correspond to the elements of FIGS. 1 to 5 are denoted by the same numbers, the edges 21 'which delimit the hole 21 formed by the base part 5' of the bracket 5 are bent upwards. The base part 5 ¹ has the shape of a V, on the two arms of which the two flat surfaces of a main cable with the shape of a section of a circle rest. This can have variable dimensions and, for example, one of the two profiles 30 and 31 ¹ , which are shown in dash-dotted lines, or an intermediate profile, with a play remaining between the cable and the inner curved surfaces 5 "of the bracket surface a series of knives which are parallel to the axis of the cable or 31 are arranged and their cutting edges point downwards. in the upper surface of the intermediate piece 18 is a sleeve in the form of a V there is provided a seat for the stripped portion of a branch cable 28 with a round shape. On the other hand , the two

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Areas 18 'of this groove serve as a support for the two flat surfaces of a branch cable 29 with the shape of a section of a circle. The jaw 15 has on its lower surface a concave portion 15 'of rounded shape which is arranged to facilitate good contact between the jaw and the branch cable 28 or 29. The screw is provided with a locking nut ^{14 l.}

The commissioning of the device of FIGS. 7 and 8 consists in that the pawl 10 is opened, that the bracket 5 is placed over the insulated main cable 30, that the intermediate piece 18 slides along the two arms of the bracket from top to bottom to lie on the Harptkö, -el that in the V-shaped groove of the intermediate piece of the stripped part of the branch cable 28 or 29 is brought, which is parallel to the cable 30, 31, that then the pawl 10 is brought into the closed position and that the screw 14 is rotated to clamp the intermediate piece 18 of electrically conductive material between the main cable and the branch cable, the blades 18 penetrate through the insulating layer of the main cable until their cutting edges come into contact with the metallic core of the cable. The clamping also causes the upstanding edges 21 'of the hole 21 to penetrate the same insulating layer, which adds to the strength of the assembly. Before geous enough, at least some of the knives 19 have serrated cutting

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2ÜA2692 * id

edges of the type described above, furthermore, the contact surfaces of the elements 15 and 18 with the branch cable have a corrugation (which is not shown and which is arranged parallel to the conductor 28 or 29, for example is), which is intended to be the non-conductive aluminum oxide layer to break through if the branch cables have an aluminum core.

K In general, this arrangement can be used both on main cables with full soul

as well as applied to cables that have a twisted metallic Soul are provided.

With the compounds according to the invention, it is expedient to take special measures in order to avoid the phenomenon of aging of the electrical contact caused by repeated periods of heating and cooling. It has been found that if the volume of the insulation of the main cable is excessively compressed in the grooves between the blades during the start-up of the connection, the insulation will tend to flow due to the heating caused by the current, which is a substantial drop in the Clamping pressure and thus a deterioration in the quality of the electrical contact.

In order to avoid this disadvantage , the contact knives are dimensioned according to the invention so that the ratio of the mean width of the grooves between the knives to the mean width of the knives has a value of

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has at least 2.5: 1. The ratio of the height of the knife to the thickness of the The insulating layer should advantageously be at least 2: 1. So are knives with a height of 4 mm that have an average width or thickness of 1 mm and which are separated by grooves with an average width of 2.5 mm, suitable for cables with a diameter of up to 14 mm, which are covered with an insulating jacket 1 to 2 mm thick made of PRC (reticulated polyethylene) or PVC (polyvinyl chloride).

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Claims (22)

to claims 1.7 Connection for electrical connections between a main cable, which is covered with an insulating layer and the stripped part of a branch cable, characterized in that it consists of a cutting element consists, which is arranged so that it at least partially surrounds the cable, further from an intermediate piece of an electrically conductive Material which is arranged in such a way that it can be brought between the connection zones of the said cables and that it can be cut with knives is provided on its surface facing the main cable, further from a means which rests on the cutting element to a Put pressure on the cables by clamping them against the intermediate piece and push the knives through the insulating layer to the metallic one Lets penetrate the soul of the main cable. 2. A compound according to claim 1, characterized in that the knife are arranged parallel to the longitudinal direction of a main cable which is surrounded by the cutting element. 3. A compound according to claim 2, characterized in that the ratio mean width of the space between the knives to the mean thickness of the knives is at least 2.5: 1. 1 0 9 8 1 3/1 A 8 8 4. Connection according to one of the preceding claims, characterized in that that at least some knives have a cutting edge of a serrated shape. 5. A compound according to claim 4, characterized in that the tips of the teeth have a length between 0.5 and 1.5 mm. 6. Connection according to one of the preceding claims, characterized in that that the cutting element consists of a bracket which is provided with a means which is arranged to be selective comes into a closed position, in which it forms a bridge between the two arms of the bracket, so that a closed frame is created, wherein the pressure means consists of a screw which is arranged on the closure means and which is adapted to be by screws approaching or moving away from the base of the bracket when it is closed. 7. A compound according to claim 6, characterized in that the bracket is made by cutting out of a metal sheet and that its deformation is carried out by pushing or pulling according to a U-profile will. 109813/1488 8. A compound according to claim 6 or 7, characterized in that a clamping jaw which is rotatably mounted on the axis of the screw is provided at the end of the screw opposite the base of the bracket. 9. A compound according to claim 8, characterized by a recess, which is formed on a surface of the closure means, then is located opposite the bottom of the bracket and which is arranged so that it can accommodate the jaw to lock its rotation relative to the screw in a predetermined direction. 10. A compound according to claim 8 or 9, characterized in that the jaw is provided with knives on its surface opposite the base of the bracket. 11. A connection according to claim 10, characterized in that the knives of the jaw are arranged so that they are parallel to the longitudinal direction of a main cable which is surrounded by the bracket. 12. A compound according to claim 8 or 9, characterized in that the jaw has a concave surface opposite the base of the bracket. 109813 / U88 originally inspected 13. A connection according to any one of claims 6 to 12, characterized in that that the intermediate piece consists of means which are able to hold the intermediate piece in the bracket, while it is along the arms of the Bracket can slide. 14. A compound according to any one of claims 6 to 13, characterized in that that the surface of the intermediate piece is opposite that of the surface provided with knives, has a profile that corresponds to the profile the bottom of the bracket coincides. 15. A compound according to any one of claims 6 to 13, characterized in that that a V-shaped groove is provided on the surface of the intermediate piece opposite the surface provided with knives. 16. A compound according to any one of claims 6 to 15, characterized in that that the closure means is rotatably arranged on one of the arms of the bracket, the other arm of the bracket and the closure means represent complementary means that can hold the closure means in its position by deformation and expansion of the arms of the bracket. 17. Connection between a main cable covered with insulation and a branch cable with metallic cores, thus identifiable 109813/1488 indicates that a connection according to claim 8 is put into operation, wherein the main cable between the knives of the intermediate piece and bumps formed on the jaw are clamped, the Stripped ends of the metallic wires penetrate the base of the bracket and spread out on the inner surface of the base to between to be clamped to the bracket and a surface having a profile fc corresponding to the intermediate piece. 18. Connection between a branch cable and a main cable in Shape of a section of a circle with a full core or a core consisting of veins, characterized in that a connection according to Claim 8 is put into operation, wherein the main cable rests by means of its flat surfaces on the two levels of the bottom of the bracket and is clamped between the base and the knife of the intermediate piece, while the branch cable, which is parallel to the main cable, stripped one Has part which is clamped between a concave surface of the jaw and a V-shaped groove on the intermediate piece. 19. Compound according to claim t8, characterized by a corrugation, which is formed on the clamping surfaces of the branch cable. 20. A compound according to claim 18 or 19, characterized by unevenness which are formed on the inner surface of the base of the bracket . 1 0 9 8 1 3 I U 8 8 . "■ .- ■ · ■■ ·: jv. · ■ '■: ■■; ■■■■ 2Ü42692 g "/ J 21. A compound according to any one of claims 17 to 20, characterized through a game between the arms of the stirrup and those to be joined Cables is provided. 22. Connection according to one of claims 17 to 21, characterized in that that the height of the knives of the intermediate piece is at least equal to twice the thickness of the insulation of the main cable. 109813/1488