IE53548B1 - A distributor strip for a telephone exchange - Google Patents

Abstract

1. A distributor strip with wire guide elements (3) and function elements (4) supported in a trough-like, metallic, earthed receptacle (1) alternately arranged in layers, where the function elements (4) are equipped with components possessing clamping elements (11, 12, 15, 16) and contact elements, which respectively form a separating or switching contact so as to be adjacent to one another for incoming and outgoing a-lines and b-lines (9, 10) to be connected to the external clamping elements (11, 12, 15, 16) and wherein a metallic, earthed screening plate (26) is inserted between two planes of mutually crossing wire guide channels (5) of a wire guide element (3), characterised in that a cable (8) which envelopes the a-lines and b-lines (9, 10) with a metallic screen is connected to the clamping elements (11, 12, 15, 16) with the screen of the cable in contact with a further clamping element (14, 17) adjacent to the clamping elements (11, 12, 15, 16) assigned to the a-lines and b-lines (9, 10), and is connected to an earthing bar (21) arranged on the function element (4), and that said screening plate (26) has lugs (25) mutually offset which come into contact with the metallic receptable (1).

Description

This invention relates to a distributor strip for a telephone exchange and comprising wire guidance and function assemblies which are contained in a trough-like metallic channel member. The function assemblies comprise clamping members and switches arranged to provide isolation or switch-through contact for incoming and outgoing connection wires connected to the clamping members.

In order that known distributor strips of this kind can be made suitable for transmitting higher frequencies, e.g. for the transmission of PCM signals or a high-speed data flow between calculating or data processing systems, it is necessary to introduce measures which result in the least possible transmission loss and interference' between incoming and outgoing lines. In such distributor strips it is already known to arrange screening plates between the wire guidance and function assemblies in order to reduce static interference between the individual assemblies.

It is an aim of the invention to provide measures for inhibiting mutual interference between the current carrying components of such distributor strips.

According to this invention there is provided a distributor strip for a telephone exchange and comprising a generally U-sheped cross-section metallic, earthed channel nentoer arranged for receiving, transversely of the channel, plate25 like assemblies comprising wire guidance assemblies and function assemblies alternately along the channel, the function assemblies providing clamping members for clamping connection wires so as to make electrical contact with the wires, said function assemblies also being arranged to provide -253548 isolating or switch-through contact for the wires, the wire guidance assemblies comprising two planar arrangements of wire guidance channels serving to guide cables containing said connection wires to the clamping members, each said cable having a metallic screen around the connection wires, said screen being connected electrically with a further clanping matter adjacent clamping members for the connection wires of the relevant cable, said screen clamping member being connected to an earth bar of the relevant function assembly, and a metallic, earthed screening plate being disposed betseen the two planar arrangements of wire guidance channels of each said wire guidance assembly, said screening plate having spaced lugs making electrical contact with the metallic channel member.

By using a screened cable, the incoming and outgoing wires are firstly surrounded by a metallic screen so that .when higher frequencies are transmitted the wires supported in the wire guidance assemblies cannot affect one another. The cable screen connected to the clamping member is connected to an earth bar of the function assembly and which is contacted for example via a spring earth plate to the chassis earth of the metallic channel member.

Although the individual wires arranged in a wire guidance plane are already electro-statically screened by the screen of the cable, since the wire guidance planes of a wire guidance assembly are adjacent one another, it is desirable to provide additional screening by inserting the metallic screening plate between these wire guidance planes.

An embodiment of the invention will now be described, by way of example, with reference to the accompany-3ing drawings in which:Fig. 1 is a front view of a portion of a' distributor strip embodying this invention; Fig. 2 is a plan view of the arrangement shown. in Fig. 1; Fig. 3 is a schematic front view of a portion of the arrangement shown in Fig. 1; Fig. 4 is a view of the arrangement shown in Fig. 3 rotated by 90°; Fig. 5 is a perspective view of a part of the distributor strip shown in Fig. 1 and; Figs. 6 and 7 are schematic diagrams of features of the part shown in Fig. 5.

The distributor strip illustrated in Figs. 1 and 15 2 comprises a (trough-like) metallic generally U-shaped cross section channel member 1 provided with cable supports 2 arranged in an angular portion of its base. Within guidance grooves plate-like wire guidance assemblies 3 are inserted into this trough-like channel member 1 and are secured there by means of notches in the channel member 1. Plate-like function assemblies 4 are inserted between these wire guidance assemblies 3 and support themselves by means of projections which engage recesses in the wire guidance assemblies. The function assemblies 4 can consist of isolating or switch25 through elements (e.g. switches) with special equipment in them.

The function assemblies 4 each possess components which are arranged in pairs in rows and each of which pairs, at the end projecting from the front side (out from the plane -453348 of Fig. 1), is designed as a clamping member for the connection, without the stripping of insulation, of connection wires which lead to the individual connection points and which serve for example as speech eignal conductors, whereas a contact component arranged inside the function assembly may be designed so that it can be used as an isolating or switch-through contact.

The wire guidance assemblies 3 each comprise two planes of wire guidance channels 5 which extend in arcs from the front side, which comprises the clamping members, to a respective one of the two lateral surfaces so that the two sets of arcs intersect one another in plan view (Fig. 2). The coplanar arcuate channels 5 which extend from the front side to one lateral surface are separated-from one another by walls 6, whereas the two planes containing the channels to the two respective lateral surfaces for each wire guidance assembly are separated from one another by an intermediate layer made of insulating material.

In order that systems of this kind can be rendered suitable for conveying high frequency signals e.g. for the transmission of PCM signals or a high-speed data flow between calculating systems, it must be ensured that the least possible transmission loss and interference between adjacent lines occur.

In the embodiment represented here, as regards an incoming screened cable 8, firstly the a- and b-wires 9 and 10 are connected to clamping members 11 and 12 arranged adjacent one another, whereas the screen 13 of the cable 8 is connected to further clanping nenber 14 which is adjacent the -553548 clamping members 11 and 12. The cable 8 can extend in known manner through one of the wire guidance channels from the front side to the lateral surface of the wire guidance assembly 3 and can subsequently be threaded through one of the cable supports 2 of the base of the metallic channel member 1.

An outgoing-cable 18 is connected to clamping members 15,16 and 17, which are adjacent to the clamping members 11,12 and 14, and extends in the same way as the cable 8 through one of the wire guidance channels 5 to the cable support 2.

The screen 13,19 of the cable 8,18 which is connected to the further olanping member 14, 17 respectively is electrically connected via an earthing wire 20 to an earth bar 21 arranged in the function assembly 4. This earth bar 21 is in turn connected to a chassis earth 23 via a spring earth plate 22.

Additional screening is provided by screening plates 26 arranged between the respective planes of the wire guidance channels of a wire guidance assembly. These screening plates 26 are provided with spaced spring lugs 25 (Figs. 5-7) which are offset relative to cne another and which establish contact via the guide grooves with the metallic trough-like channel member 1.

As can be seen from Fig. 3 and Fig. 4, the earthing points of the screening plates 26 are located in the regions 27,28 of the outer walls of the trough-like channel member 1, and, as indicated by the circle 29, the a- and b-wires are each surrounded by the screen 13 of the relevant cable. -653548 In Fig. 5 a portion of a wire guidance assembly is referenced 3, whereas the front surface arranged in a plane with the clamping members is referenced 30, and one of the two lateral outlet surfaces is referenced 31. As shown in Figs. 6 and 7, the U-shaped lugs 25 are arranged at the inner end of the screening plate and provide electrical contact with the metallic trough-like channel member.

If a magnetic earth screen is required between the individual wire guidance planes this can be achieved by the use of screens of magnetic material.

Claims (5)

1. A distributor strip for a telephone exchange and ' conprising a generally U-shaped cross-section iretallic, earthed channel member arranged for receiving, transversely of the channel, 5 plate-like assemblies conprising wire guidance assemblies and function assemblies alternately along the channel, the function assemblies providing clamping members for clamping connection wires so as to make electrical contact with the wires, said function assemblies also being arranged to provide 10 isolating or switch-through contact for the wires, the wire guidance assemblies comprising two planar arrangements of wire guidance channels serving to guide cables containing said connection wires to the clamping members, each said cable having a metallic screen around the connection wires, said 15 screen being connected electrically with a further clanping menber adjacent clamping members for the connection wires of the relevant cable, said screen clamping member being connected to an earth bar of the relevant function assembly,, and a metallic, earthed screening plate being disposed between the two 20 planar arrangements of wire guidance channels of each said wire guidance assembly, said screening plate having spaced lugs making electrical contact with the metallic channel member.

2. A distributor strip as claimed in claim 1, wherein 25 the further clanping menber which is oonnected to the screen of the cable is connected via an earthing wire to the earth -853548 bar which is contacted via a spring earth plate to a chassis earth of the metallic channel member.

3. A distributor strip as claimed in claim 1 or claim 2 wherein the channels in each of the two planes of each wire 5 guidance assembly extend between a front side of the distributor strip, corresponding to the open side of the channel member, and a respective lateral portion of the channel member through which said screened cables can extend.

4. A distributor strip as claimed in any one of the pre10 ceding claims wherein a screen of magnetic material is also provided between the wire guidance planes of each wire guidance assembly.

5. A distributor strip for a telephone exchange according to claim 1 and substantially as described herein 15 with reference to the accompanying drawings.