EP0700126B1 - Plug for a multiconductor cable - Google Patents

Abstract

Each core (2) of the cable (1) is connected electrically to a pin (11) of the plug by way of a terminal block (7) and a fastening element (8) with cut-and-grip connection tags (10). The pins are accessible from outside via an opening (35). The wire braid forming the screen (3) is joined to an external earth connection by a ring (12) of pref. highly conductive material slid over the end of the cable sheath (4) and laid ina circumferential groove (16.1) when the plug is closed. This arrangement provides strains relief and solderless connection for charge dissipation.

Description

The present invention relates to an arrangement of a plug and a cable with a plurality of wires, which are jointly enclosed by a metal shield which runs within a cable sheath, with a plug housing, with a first device for electrically connecting the wires to one in the housing arranged connector pole, the connector poles for establishing an electrical connector are accessible from outside the housing, and with a second device for electrically connecting the shield to a ground or ground connection.

In particular, the plug according to the invention is designed as a plug socket and is intended for class D and future class E building cabling, in particular for RJ 45 type interfaces. The classes determine the transmission quality of entire transmission links or transmission systems from one plug socket to another plug socket. Appropriate standards such as EN 50173, for example, set limits for maximum attenuation, for crosstalk, for reflections, etc., as well as for the maximum permissible frequencies. In class D transmission systems, for example, this is 100 MHz. For class E, the specification of which has not yet been finalized, it is planned to work with frequencies up to 300 MHz.

It is in the trend of technical progress to no longer create building cabling separately for telephones, EDP systems, video systems etc. in the future, but only to provide a single building cabling network via which the information and data can be transmitted from all relevant services will. A start has been made with ISDN (Integrated Services Digital Network).

It is also in the trend of technical progress to transfer ever larger amounts of data, faster and faster. For this purpose, ever higher demands are being made on cables and plugs to achieve certain electrical limit data. This applies in particular to the connection of the cable shield to the plug. Today, this is usually the case metal clips, rings or connecting lugs are placed around the shield end of a cable end inserted into a connector using tools and pressed around the shield using a crimping or other tool. To lead the shield out of the plug housing to an earth connection, the clip, for example, which is placed around the end of the shield, can itself have a connection lug directed radially to the cable, which is intended for connecting a cable lug to a ground or earth line. It can also be provided that a wire is inserted between the end of the shield and the part pressed around the shield, which may have been previously soldered to the shield and is led out of the plug as a ground wire. A drain wire that is present in many cables and runs parallel to the screen can also be used.

A tool is required for all of these connection technologies for the shield, which are only mentioned as examples. By pressing, pressing on or enclosing the shield at the end of the cable with the techniques mentioned, a radially directed pressure is exerted on the wires of the cable, which pressure can change the electrical properties of the cable. The shield tap led out of the connector usually goes from a single point on the shield. In particular, the latter two points are not conducive to a further increase in the maximum transmission frequency, as is provided, for example, in a future class E cabling system.

It is therefore the object of the present invention to provide a connector in which the shield connection for the cable of the type mentioned at the beginning is improved in such a way that the disadvantages mentioned above do not occur.

This object is achieved with a connector of the type mentioned at the outset, which is characterized in that the second device has a ring with at least one metal outer jacket surface, which is placed loosely over the cable end inserted into the connector, that the from the to the Area of the ring distant cable sheath protruding shield is guided over the outer surface of the ring and that within the housing essentially along the entire outer surface and opposite to it there is an electrical contact element which is electrically connected to the ground or ground connection.

The ring which is provided for the loose pushing over the cable end can be designed such that an annular air gap is formed between the shield surrounding the wires and the ring or between the cable jacket and the ring. The shield can be guided around the outer circumferential surface of the ring without the aid of a tool. It is preferably provided that the ring is located approximately above the jacket end and the screen is folded back around the ring against the inserted cable. No cross pressures are generated on the cable. The cable end is not deformed.

The fact that the shield of the cable, which usually has a wire mesh, is distributed in the radial direction as evenly as possible over the entire circumference of the ring over its outer circumferential surface, the properties with regard to electromagnetic compatibility (EMC) can be improved.

Instead of the at least metal outer jacket surface, the ring is preferably produced as a metal ring made of an electrically highly conductive material. However, a metal ring or a plastic ring can also be provided, the surface of which is made of an electrically highly conductive material. is completely covered.

The housing of the plug is designed such that the outer circumferential surface of the ring is preferably completely surrounded by an electrically conductive contact element or an electrically conductive contact track. This contact track is directed against the outer lateral surface and, in the case of the ring arranged in the housing, presses against the screen fabric which is guided as uniformly as possible in the circumferential direction over the outer lateral surface of the ring. This provides electrical contact between the ring, the screen fabric and the contact track, which extends around the entire circumference of the ring. In a modified version could also it should be provided that the electrical contact path, which usually corresponds approximately to the ring width, would be made less wide than the latter. It could also have one or more break points along its circumference.

Advantageously, the electrical contact element is simultaneously designed as a stop element in such a way that the ring is thereby held stationary within the housing with respect to the longitudinal axis of the cable. In an advantageous embodiment, this can be achieved in that a groove extending along the circumference of the ring is present within the housing, into which the ring with the folded-up screen extends. At the same time, this relieves the strain on the cable relative to the connector. An additional cable tie, which is wrapped around the cable end, generates disadvantageous radially directed forces thereon, and is provided for connectors belonging to the prior art for strain relief of the cable relative to the connector, is not necessary in the connector according to the invention because of the aforementioned construction.

The housing of the plug, which essentially comprises a base part and a cover with which the base part, which is at least partially open for connecting the wires, can be closed, can be made of metal. The metal could be suitable to shield electromagnetic fields. The ring inserted into the said groove with the flipped-over screen would lie against the inner wall of the metal housing and establish an electrical contact that extends along the entire groove with the housing. Due to the complexity of the housing parts, these are preferably created as a plastic injection molded part. The entire surfaces of the housing parts are provided with a metal coating by means of a galvanic process which is known. A first layer is an electrically highly conductive layer made of copper, which is also used to shield electromagnetic fields. A second layer of nickel is used primarily to protect against corrosion. In this case too, the ring is connected to the housing by an electrical contact track that extends over the entire circumference of the ring.

The ground or ground connection, which is preferably designed as a cylindrical connecting tongue, can be attached to the outside of the housing and is connected to the aforementioned contact path via the metal coating of the housing. The earth or earth connection is molded directly onto one of the latter when the housing parts are manufactured. It can be on the base or on the cover.

Since different masses or groundings or mass systems or grounding systems are often present in electrical systems, it has proven to be advantageous to provide a second ground or ground connection on the outside of the plug housing. In this way, additionally installed plugs can easily be looped into existing ground or earthing systems. It is also easily possible to change from a grounding or earthing system to another grounding or earthing system without having to do any soldering. All that is required is to plug in connectors, preferably in the form of round sleeves that are plugged onto the cylindrical connecting tongues. This direct connection without solder connections guarantees a very good transition contact from the connecting tongue to the earth or earth wire to which the connector is connected.

• Fig. 1 eine isometrische Darstellung eines erfindungsgemässen Steckers, ohne Kabel, bei dem ein zweiteiliges Gehäuse geöffnet und ein Ring angehoben ist,
• Fig. 2 Teile des erfindungsgemässen Steckers gemäss der Fig. 1, insbesondere eine Grundplatte mit Schneid-Klemm-Anschlussfahnen, welche innerhalb dem Steckergehäuse montiert ist, ein Klemmblock mit in dafür vorgesehenen Öffnungen eingeführten Adern eines Kabels, welcher von der Grundplatte mit den Schneid-Klemm-Anschlussfahnen abgehoben ist, sowie den Ring, der lose über das Kabelende geschoben ist, und
• Fig. 3 eine Aufsicht auf den Stecker gemäss der Fig. 1, wobei das Kabel angeschlossen und der Stecker ohne Gehäuseabdeckung gezeichnet ist.

An embodiment of a connector according to the invention is described in more detail below with reference to figures. Show it

• 1 is an isometric view of a connector according to the invention, without a cable, in which a two-part housing is opened and a ring is raised,
• 2 parts of the connector according to the invention according to FIG. 1, in particular a base plate with insulation displacement terminal lugs, which is mounted inside the connector housing, a terminal block with wires of a cable inserted into openings provided for this purpose, which Clamp connection lugs is lifted off, as well as the ring, which is loosely pushed over the cable end, and
• Fig. 3 is a plan view of the connector according to FIG. 1, the cable being connected and the connector being drawn without a housing cover.

1, 2 and 3, an embodiment of a connector according to the invention is shown. In the isometric view of FIG. 1, the plug, which is encompassed by a two-part plug housing 5, 6, is shown without a cable and in the open state. The two-part housing consists of a base part 5 and a cover 6, which snaps onto the base part when it is placed on it. To this end, a snap-in rib 36 is provided on the long side of the base part and a snap-in tongue 37 is provided on the cover. When the cover 6 is placed on the base part 5, the latching tongues snap over the latching ribs, as a result of which the cover is held on the base part.

The two parts of the connector housing 5, 6 are preferably made of plastic. In particular, they are made as injection molded parts from a thermoplastic. The two parts of the connector housing are coated on all sides with a metal layer. The coating is created in a known manner using a galvanic process. A first coating comprises a copper layer which conducts electricity well and, as described further below, is intended for the electrical connection of a screen of a cable inserted into the plug to a ground or ground connection 13, 17 arranged on the plug connection side. The copper layer also shields the inside of the connector from electromagnetic fields. A nickel layer, which is primarily intended to protect against corrosion, is applied over the copper layer.

In the interior of the plug housing, in the base part 5, there is a part 8 with insulation displacement terminal lugs, which are not visible in FIG. 1, and with a module 33 with plug poles. Part 8 comprises a printed circuit board 9. The insulation displacement terminal lugs and the module 33 are soldered to the printed circuit board 9. The module 33 has an insertion opening 35 in which the plug poles are accessible and when a corresponding plug counterpart is plugged in with the plug poles of the latter electrical connection. The connector shown as an embodiment is provided to establish an electrical connection according to the RJ 45 standard. The module 33 is usually shielded from electromagnetic fields by means of a sheet metal encapsulation.

A part 7, a terminal block, is placed over the connection lugs, not shown, which are arranged on the printed circuit board 9 between the module 33 and a cable insertion opening 32. This is preferably also made as a plastic injection molded part made of a thermoplastic. In the example shown, it is essentially cuboid in shape, has a base area which, when plugged in, faces the printed circuit board 9 and rests thereon. First openings 18, into which the terminal lugs protrude when the terminal block 7 is in place, extend continuously from the base to a top surface of the terminal block 7. The first openings 18, one per terminal lug, have a cross section which is essentially similar to that of the terminal lugs is. In the example shown, this is a rectangular cross section. The clamping block 7 furthermore has second openings 19.1, 19.2 which extend from one of the cable entry openings 32 facing insertion surface 20 of the clamping block 7 completely through the latter, to a rear side opposite the insertion surface 20 or to the side surfaces of the clamping block. A second opening 19.1, 19.2 each intersects a first opening 18 at approximately a right angle. In the longitudinal direction of the first openings 18, the second openings 19.1, 19.2 are arranged offset in height from one another in several, preferably in two positions. The printed circuit board 9 is closer to a first layer of second openings, which are designated by 19.1. These extend from the insertion surface 20 parallel to a longitudinal axis of the plug to the rear of the terminal block. A further distance from the printed circuit board 9 of second openings, which are designated by 19.2, extend from the insertion surface 20 at an acute angle with respect to the longitudinal axis of the plug towards the side surfaces of the terminal block. A partial area of the insertion surface 20, the area in which the second layer of the second openings 19.2 is located, is designed as a concavely curved partial surface 24 facing the cable insertion opening 32. In the example shown, this partial area is trapezoidal. It has two side areas, the are marked with 24.1 and 24.2. Two second openings 19.2 each extend from each of the side regions in the direction of the adjacent side surfaces of the clamping block 7.

The circuit board 9 with the insulation displacement terminal lugs attached to it and with the module 33 is generally designated as part 8 and the terminal block as part 7 of a first device 7, 8 for electrically connecting the wires of a cable, each with a plug pole arranged in the housing.

For precise guidance when the clamping block 7 is placed over the connecting lugs, insertion grooves 30 are provided in the side walls of the base part 5 of the plug housing, into which insertion ribs 29 (FIG. 2) of the clamping block 7 can be inserted.

Adjoining an end face 31.1 of the base part 5 facing the cable to be connected to the plug, in which the cable insertion opening 32 is arranged, a semicircular groove 16.1 is provided which extends at right angles to the longitudinal axis of the plug. An identical semicircular groove 16.2 is subsequently present in an end face 31.2 in the cover 6 facing the cable to be connected to the plug. When cover 6 is placed on base part 5 of the connector housing, groove 16.1, 16.2 is circular. Inserted into this groove is a ring 12, which is generally named as a second device 12 for electrically connecting the shield of a cable to the ground or ground connection 13, 17. The ring 12 is preferably made of an electrically highly conductive material. However, another material, metal or plastic, could also be provided. It is essential that the outer circumferential surface of the ring 12, designated 14, is electrically good conductive. In the case of a plastic ring, this can be achieved, for example, with a metal coating, similar to that described above. The groove 16.1, 16.2 is dimensioned such that the ring has some play both in its longitudinal axis and in the direction of its diameter.

The cylindrical connecting tongues 13, 17 are provided for receiving connecting plugs, in particular round sleeves 39, to which earth or earth wires 38 are connected.

Now that the individual parts of the connector according to the invention and their arrangement have been described, the procedure for connecting the connector to a cable will be described with reference to FIG. 2. For this purpose, only the first device 7, 8 for electrically connecting the wires 2 of a cable 1 with plug poles of the plug and the second device 12 for electrically connecting a shield 3 of the cable 1 with the above-mentioned ground or ground connection are shown in FIG. 2.

The first device 7, 8 comprises the terminal block 7 and that part of the printed circuit board 9 with the insulation displacement terminal lugs 10 arranged thereon. The terminal block 7 is drawn in a state lifted from the terminal lugs 10.

The second device comprises the ring 12 with the above-mentioned outer surface 14 which is a good electrical conductor. The cable 1 to which the connector according to the invention is to be connected comprises the multiple wires 2, in the example shown eight wires which are twisted in pairs (not visible from the figure) ) run inside a cable jacket 4. The shield 3 is present between the inner surface of the cable jacket 4 and the wires 2. The shield 3 has a layer of wire mesh that completely surrounds the wires. Several wire mesh layers or further layers made of a metal foil, in particular an aluminum foil, are also conceivable.

To connect the plug to the cable, the sheath 4 is removed from the latter in an end region, the exposed position of the wire mesh of the shield is folded back over the remaining sheath and any further shields are removed such that the wires 2 are exposed from the end of the sheath. The ring 12, which has been pushed over the jacket beforehand, or is pushed over the jacket over the inverted wire mesh of the screen 3, is now arranged such that it is in the region of the jacket end comes to rest, the wire mesh of the screen being placed over the outer jacket surface 14 of the ring 12. This should be done in such a way that the wire mesh extends away from the cable in the radial direction as evenly as possible, so that the outer circumferential surface of the ring is covered by the wire mesh over the entire circumference of the latter as far as possible. The ring 12 is loose with respect to the jacket 4 of the cable, ie an annular gap can be formed between the inner jacket surface of the ring and the outer jacket surface of the cable. In any case, the ring sits so loosely over the end of the cable that it does not exert any radial forces on the latter.

The individual wires 2 of the cable 1 are now inserted from the insertion surface 20 of the clamping block 7 into the second openings 19.1, 19.2 such that they all protrude from the latter on the other sides of the clamping block. The distance between the end of the jacket 4 of the cable 1 and the insertion surface 20 of the clamping block 7 is now approximately adapted to the position of the groove in the housing relative to the connection lugs. All the protruding ends of the wires 2 are then cut off with a side cutter. The remaining ends 27 of the wires 2 are then practically flush with the side surfaces from which they previously protruded. For the wires 2 which protrude into the second openings 19.1 of the position closer to the printed circuit board 9, this is the rear side 23 of the clamping block 7 opposite the insertion surface 20 and for the wires 2 which protrude into the second openings 19.2 of the higher position with respect to the printed circuit board 9 , these are the side surfaces 21 and 22 of the terminal block 7. Prepared in this way, the terminal block 7 is now placed on the connecting lugs 10. One of the connection lugs protrudes into one of the first openings 18. When the terminal block is pressed down in the direction of the printed circuit board 9, the individual wires are pressed into the slots 28 of the insulation displacement terminals. The relatively sharp slot edges cut open the insulation of each of the wires. The wire which is now bare in the area of the slot is then clamped between the two resilient tabs of the connecting lug 10 between which the slot 28 is formed.

The assembled state of the plug on the cable can be seen in a top view from FIG. 3. The cover 6 is not yet installed there. When the clamping block 7 is depressed, the ring 12 with the wire mesh of the shield 3 which is turned over it lies in the groove 16.1 of the base part. The play of the groove to the ring is such that there is just enough space to accommodate the screen. By the direction of the second openings 19.1, 19.2 and by the dimension of the terminal block 7, when the terminal block 7 is attached, both the course and the direction of each individual wire and the length of each individual wire within the connector are defined and the same for each connector.

When the cover 6 is in place, the ring 12 is then located in the circumferential groove 16.1, 16.2 together with the shield 3 of the cable which is turned over its outer circumferential surface 14. The screen 3 is distributed over the entire circumference of the groove on the end faces and on the outer surface of the groove. The metal coating of the connector housing 5, 6 acts as a contact element or electrical contact path for establishing an electrical connection between the ring 12, the shield 3 and the connector housing 5, 6, in particular the connecting tongues 13, 17, for the ground or earth connections the outside of the cover 6 are arranged (Fig. 1).

Through the groove 16.1, 16.2, the ring is held stationary with respect to the longitudinal axis of the connector. The groove acts as a stop element for the ring. The groove thus not only makes electrical contact between the shield and the plug tongues 13, 17, but together with the ring is also responsible for the strain relief of the cable 1.

Reference number 11 denotes the connector poles which are arranged in the module 33 and are accessible from the insertion opening 35. Each of the plug poles is connected to a conductor track 34 on the printed circuit board 9 with an associated insulation displacement terminal lug 10. From Fig. 3 the fixedly specified guidance of the individual wires and the defined length of the latter within the connector housing 5, 6 can be seen very nicely. In particular through the trapezoidal partial surface 24 of the insertion surface 20 and the second openings arranged in the side regions of this partial surface 19.2, a defined acute-angled routing of certain wires with respect to the longitudinal axis of the connector is deliberately achieved.

Finally, it should be noted that the first device 7, 8 for electrically connecting the wires 2 of the cable 1 to the plug poles 11 of the plug is not limited to designs with a shielded cable. The advantages mentioned, which are achieved with the terminal block 7, in that the wires are inserted into the corresponding second openings 19.1, 19.2 in the terminal block 7 via the insulation displacement terminal lugs 10 before the terminal block 7 is pressed on, also remain in the case of cables without shielding receive. However, other strain relief must then be ensured.

Claims (10)

1. Configuration of a connector and a cable with several wires (2), which are jointly enclosed by a metallic shield (3) which runs inside a cable jacket (4), with a connector housing (5, 6), with a first device (7, 8) for electrical connection of the wires (2) with one connector pole (11 ) each disposed in the housing, the connector poles being accessible from outside the housing to establish an electrical plug connection, and with a second device (12) for electrical connection of the shield (3) with a ground or earth connection (13, 17), characterised in that the second device has a ring (12) with at least a metallic outer generated surface (14), which ring is placed loosely over the cable end introduced into the connector, in that the shield (3) emerging from the cable jacket (4), removed up to the area of the ring (12), is led over the outer generated surface (14) of the ring (12), and in that there is an electrical contact element (16.1, 16.2) inside the housing, essentially along the entire outer generated surface and opposite thereto, which contact element is connected electrically to the ground or earth connection (13, 17).
2. Configuration according to claim 1, characterised in that the ring is a metal ring (12) made of a material that conducts electricity well, or a plastic ring (12) provided with a surface covering made of a material that conducts electricity well.
3. Configuration according to claim 1 or 2, characterised in that the electrical contact element is a stop element (16.1, 16.2) with which the ring (12) is held stationary inside the housing (5, 6) with respect to the longitudinal axis (15) of the cable (1), the stop element being preferably a groove (16.1, 16.2) provided in the housing (5, 6) extending along the circumference of the ring (12).
4. Configuration according to one of the claims 1 to 3, characterised in that the housing (5, 6) is made of a plastic, the entire surface of the housing being provided with a metallised covering which preferably contains copper.
5. Configuration according to claim 3 or 4, characterised in that the housing comprises at least two parts (5, 6), a base part (5) and a cover (6), with which the at least partially opened base part (5) is closable, and in that the groove (16.1, 16.2) runs partially through the base part (5) and partially through the cover (6).
6. Configuration according to one of the claims 1 to 5, characterised in that the ground or earth connection (13) is disposed on the outside of the housing (5, 6) and is designed preferably as the connection tongue.
7. Configuration according to claim 6, characterised in that further, preferably a second, ground or earth connection (17) is, or respectively are, disposed on the outside of the housing (5, 6).
8. Configuration according to claim 7, characterised in that the ground or earth connection (13, 17) is disposed on the cover (6).
9. Configuration according to one of the claims 1 to 8, characterised in that the shield of the cable (1), the shield usually having a wire mesh (3), is led over the outer generated surface (14) of the ring (12) in radial direction distributed as evenly as possible over said ring circumference.
10. Configuration according to one of the claims 1 to 9, characterised in that an annular air gap is formed between the inner generated surface of the ring (12) and the jacket (4) of the cable (1 ) and/or the shield (3) of the cable (1).

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