NO166369B - PROCEDURE FOR THE PREPARATION OF MUCOPOLYSACCARIDES WITH HIGH ANTITROMOBOTIC ACTIVITY. - Google Patents

Description

Cable, preferably for transmission of telecommunication signals, and method

for the production of this.

The present invention relates to a cable of the type which is preferably used for the transmission of telecommunications signals, and which comprises a plurality of insulated conductors arranged in one or more groups. The term "cable" is used here in its broadest sense. Thus, e.g. wires, cords belonging to such, overhead lines, etc. The invention also includes a method for producing such a cable.

Symmetrical circuits are mainly used for the transmission of telecommunication signals over cable. In the simplest version of such a cable, each group of conductors contains only two conductors, i.e. a pair. The two conductors in the pair are arranged below so that they have identical characteristics in relation to their surroundings, e.g. earth, cable jacket or an adjacent pair in the cable. To achieve this, both conductors are not only produced with one and the same conductor diameter, but also have geometrically and electrically similar insulation layers. Furthermore, the conductors in such a cable are twisted in each pair, partly to achieve a unit that is held together, partly to ensure that the voltages, respectively currents, which are induced in the two conductors by foreign electric and magnetic fields, will remain in the main equal in size and equally directed in the two conductors, so that no resulting disturbance current or voltage occurs in the pair. In order for interference, so-called crosstalk, not to occur between different pairs in one and the same cable, it is required that the twist pitch is different at least for adjacent pairs.

A signal transmitted on a pair of conductors is weakened or attenuated along the length of the cable. The size of the attenuation depends primarily on the resistance of the conductors, but also on the capacity between the conductors, the size of which is a function of the distance between them. Closely joined conductors thus have higher damping than those that have a large gap available. It has been shown that for a given cable cross-section, lower attenuation can be achieved for each pair of conductors by combining the conductors into groups in a special way. Instead of arranging the leaders in groups of two leaders, it has therefore been proposed to combine these into groups of four leaders.

The simplest version of such a group consisting of four conductors is a so-called star four. Freedom from interference between the two pairs of conductors in a four is thereby achieved by each pair being formed by conductors located diagonally opposite each other in the four. An investigation of the electric and magnetic fields

produced by currents flowing through one pair shows that these fields cannot cause any resultant induced disturbance in the other pair.

In addition to the fact that, with a given dimensioning of the cable, lower attenuation is achieved when the cable consists of a number of so-called star-fours, than when it consists of a number of conductors twisted in pairs, with a cable consisting of fours, you can also achieve an even better output utilization of both space and the total number of conductors. In such a four-way cable, a third circuit, a so-called fan-empty circuit, can be introduced, one conductor part of which is formed by the two conductors in one pair and the other conductor part is formed by the two conductors in the other pair. A more detailed description of the connection and application of the phantom circuit does not seem to be necessary in this context.

As previously mentioned, the attenuation also depends on the capacity of the respective pairs of conductors. It has been found that there is a definite relationship between the capacities of the pairs and the phantom circuit in the case of a four-wire cable. Especially when using pupinisation, transmission of the same frequency band results in significantly higher attenuation in the phantom circuit than in the pair circuits. This is a definite disadvantage,

since of course you usually want to achieve one and the same attenuation in all circuits in the cable. It has been mentioned above that with pair winding, quadrature etc. it is possible to prevent or eliminate interference from the outside, or between different circuits in one and the same cable. However, this is valid only in purely ideal cases. Thus, in practice, complete symmetry is never achieved. It has proven to be particularly difficult to get good interference freedom between the phantom circuit and the pair circuits in a star quad. This, together with the fact that the attenuation in the phantom circuit is relatively large compared to the attenuation in the pair circuits, has meant that the phantom circuit in the star four is rarely used.

There is also a further well-known type of four arrangement, namely the so-called Dieselhorst-Martin four or DM four. This consists of two conductor pairs that are twisted separately in the usual way, which in turn are twisted together to form a four. Each pair thereby has a pitch which is different from the pitches in the other pair and in the four arrangement, and which is also different from the pitch of at least the nearest adjacent fours. It has been shown that the practically achievable freedom from interference is better with the DM quadruple than with the star quadruple. In the case of the DM four, the attenuation of the phantom circuit is also somewhat lower than that of the pairs. This relationship, together with the more favorable cross-talk values of this quad type, has meant that the DM quad is the one of the aforementioned two quad types that has come into greatest use in connection with the utilization of the phantom circuit.

In order to eliminate the difficulties in reducing the transmission between different pairs that particularly occur when producing cables that contain a number of pairs or fours, respectively a number of cords, it has been proposed that when the conductors are twisted to form a pair or a four, respectively a cord, an arbitrary variation of the twisting or cabling pitch along the length of the wire is produced, at least within certain limits. E.g. in a cord made in this way, however, pairs or fours that lie next to each other in a certain section will also come to lie next to each other in every other section along the length of the cord. The danger of crosstalk between adjacent pairs or fours is therefore still great even with cables designed in this way.

To reduce cross-talk within a management group or between adjacent management groups, it has been proposed to alternate the position of certain managers, or pairs of managers, along a shorter distance, which is determined by measuring the cable's electrical characteristics. This precaution makes it possible to achieve a reduction of the crosstalk between certain pairs of managers. However, it is obvious that this method does not lead either

an almost complete elimination of hearings within a management group, or between different management groups. Before this can be achieved, it is required that all conductors within such a conductor group must have identical electrical properties.

The purpose of the invention is to provide a cable that meets the aforementioned requirement. A cable made according to the invention is primarily characterized by the mutual positions of the conductors within at least one group containing at least three conductors, and/or the mutual positions of at least three groups within the cable, alternate in such a way along the length of this that for a given length in relation to the distance between successive exchange points. cable length is the sum of the sections along which two arbitrarily selected conductors within said group, respectively two arbitrarily selected groups, are immediately adjacent to each other, approximately constant and independent of how the respective conductors, respectively groups, are selected.

In the case of a cable with conductors intertwined into groups according to the invention in the manner indicated above, the partial capacities between the different conductors within each group will be equal, whereby all conductors within the group become completely equivalent. One can thus select two arbitrary leaders within a group to form a pair. If the group consists of four leaders, the second pair is thus formed from the other two leaders. This leads to three options when it comes to the leaders' combination into pairs. One of the advantages of a cable constructed in this way,

by which one can combine the conductors of pairs in three different ways, the increased possibility of obtaining a pair with low crosstalk, respectively a pair that is well suited for combining with another cable to reduce the total crosstalk. With previously known cable types, there is no such option.

the visibility that there is an equally large overhearing value in the other cable, but with the opposite polarity, is thus three times greater than with the known quad types. The possibility of providing a cable system with very low crosstalk values is therefore great. It should also be emphasized that the most troublesome crosstalk, namely that between the phantom and pair circuits, has been shown to be low with a cable designed according to the invention. Furthermore, a cable according to the invention also has the advantage that relatively small deviations between the attenuation values for the pair circuits and the phantom circuits are achieved. In a cable whose cable bundle is made up of conductor groups whose mutual positions vary in the above-described manner along the length of the cable, all groups have essentially the same properties, e.g. in relation to the cable's jacket and other parts or components of the cable. In addition, low crosstalk values are achieved between the groups, as these are not adjacent to each other along the entire length of the cable. This is not achieved when the groups are arranged in concentric layers in a previously known manner.

It must also be stated that the invention allows the use of an arbitrarily high number of conductors within each group. In automatic switching technology, it is therefore desired, e.g. often to introduce a group with a speech circuit consisting of a pair and one or more conductors for relay operation. The relay currents can below be transferred with e.g. earth as a feedback conductor, without there therefore needing to be overhearing of the speech circuit. A cable constructed in accordance with the invention may optionally also contain one or more differently constructed fours or pairs or one or more coaxial cables,

like for example. can form a core around which a number of fours or groups designed according to the invention are arranged.

When the idea of the invention is applied to the construction of cord cables, the various cords can possibly be formed either by groups or conductors constructed according to the invention or by pairs or fours with conventional design, or also by both conventional conductor groups as such constructed according to the invention.

As previously mentioned, the invention also includes a method for producing a cable of the type described above, in which at least three insulated conductors, respectively groups of such conductors, are each placed on a supply coil etc. , is unwound from the supply coils and brought together into a bundle which is wound on a collection drum. According to the invention, this manufacturing method is characterized in particular by the fact that in connection with the bringing together of the conductors, respectively the groups, to the mentioned bundle, the mutual position of these is alternated along its length in such a way that for a given in relation to the distance between consecutive switching points along the length of the cable is the sum of the sections along which two arbitrarily selected conductors within said group, respectively two arbitrarily selected groups, are immediately adjacent to each other, approximately constant and independent of how the respective conductors, respectively groups, are selected.

According to the invention, they can lead, respectively groups

of conductors that are brought together to form a bundle, a twist is imparted about the longitudinal axis of the bundle in connection with their winding on the collection drum.

The invention will be described in more detail below with reference to the drawings, in which: fig. 1 shows a perspective view of a device for manufacturing

of a cable according to the invention while

fig. 2 and 3 show detailed drawings that illustrate the control of the holders that carry the supply coils in the aforementioned device,

°9 produced»

fig. 4 schematically shows a cable/using the device on

fig. 1.

At the one in fig. 1 device shown, there are four supply coils 1 which carry the conductors, respectively conductor groups, which are designed to be included in the finished cable. The supply coils 1 are supported by fork-like holders 2 which, with reference to fig. 2, consists of an upper part 3 designed as a U-shaped hoop, in which a supply coil 1 is stored freely rotatable, and a lower part 4 designed as a circular pin, hereinafter referred to as a guide pin. The spool holders 2 are guided by their vertical guide pins 4 in horizontal guide tracks 5,6,7 and 8 in a stand 10 which rests on a horizontal base 9. This stand consists of a horizontal plate 10a which is supported at a certain distance above the base 9 by means of vertical legs 10b and in which the aforementioned guide grooves 5,6,7 and 8 are designed. It appears from fig. 1 that the grooves 5 and 6 are circular and located at opposite ends of the plate 10a, while the grooves 7 and 8 together form an ellipse which is tangent to the first-mentioned grooves. The stand plate 10a is divided by the guide grooves 5,6,7 and 8 into four separate parts, namely two cylindrical plates 11 and 12, an elliptical ring-shaped part 13 which forms the outer peripheral part of the plate 10a, and an inner elliptical plate 14 which at each end is designed with circular recesses. Parts 11, 12, 13 and 14 of the parts 11, 12, 13 and 14 adjacent to the grooves 5, 6, 7 and 8 form sliding surfaces on which the holders 2 rest by means of ring-shaped flanges 15 which are firmly placed on the guide pins 4 (see fig. . 2). The spool holders 2 are prevented from tipping over in the guide grooves by means of locking rings 16 which are placed on the guide pins 4 immediately below the stand plate 10a..

The circular plates 11 and 12 each carry a pivot arm 17 and 18, respectively, which are stored centrally on the relevant plate and extend diametrically in relation to the plate and are provided at each end with a gripping member 19 adapted to influence the coil holders 2, which member is articulated with the pivot arm 17 and 18 respectively and at its free end has a U-shaped recess for receiving the guide pin 4 on a spool holder 2. Each of the gripping members

19 is spring-loaded in the direction towards an inner end position, in which the member's outlet is located at a distance from the pivot axis of the pivot arm 17, respectively 18, corresponding to the radius of the circular grooves 5 and 6. Furthermore, each gripping member 19 is provided on its underside with a track 20 which is arranged to cooperate in a more detailed manner with a pin 21 which is actuated by an electromagnet 22 arranged to shoot said pin up through a hole in the outer annular part 13 of the stand plate 10a, depending on supplied control signals. Such a pin 21 for cooperation with the slot 20

in the gripper 19, with the associated electromagnet, is firstly arranged at the transition between the tracks 6 and 8, and secondly at the transition between the tracks 5 and 7. The two pins 21 are arranged so that they are in the raised position when cooperating with the track 20 in a passing gripper 19, causes this to be swung radially outwards to such a position that a spool holder 2 which is displaced by the gripper along the circular, guide track 5 or 6, is transferred to the guide track 7, respectively 8.

For the transfer of the coil holders 2 between the circular grooves 5 and 6 along the groove 7, respectively 8, there is arranged a special transport organ in fig. 3 shows, for example, an embodiment of such a body, consisting of a belt conveyor in the form of one inner belt 2 3 and an outer belt 24, the former of which rests against support rollers 25 which are evenly distributed along the length of the relevant track 7, respectively 8 , which support rollers are rotatably stored in the edge part of the plate 14 which borders the groove, while the other belt 24 extends radially outside the inner one. When a spool holder 2 with its guide pin 4 is introduced between the two belts 23 and 24, it is caught and transported by these to the far end of the transfer track 7, respectively 8, where it is then gripped by the first passing gripper 19.

The conductors placed on the coils 1, respectively conductor groups 26, are unwound or released from them during cable production. whereby they pass through a collector ring 27 and a turntable 28

both of which are carried by a boom 29. For the forward feeding of the cable formed by the conductors 26, separate bodies are arranged which consist of two double-track line sheaves 31 supported by a fixed holder 30, from which sheaves the cord is fed to a collection drum 32 which is rotatably stored in a frame 33 which in turn is rotatably supported by two holders 34 and 35. In the bearing pin for the frames 33 which rests in the holder 34, a central hole is designed

through which the cable passes into the collection drum 32, which is rotatable by the frame 33 in a plane that includes the drum's axis of rotation.

The operation of the device described above will be explained in more detail below.

The conductors placed on the coils 1 are unwound from them under the influence of the line sheaves 31 and the collection drum 32, whereby they are brought together by the collector ring 27 to form a bundle of conductors which forms the finished cable. At the same time, the coil holders 2 affected by the gripping means 19 are caused, together with the coils 1 on them, to move in pairs along the circular guide tracks 5 and 6, whereby the aforementioned movement is provided by the rotary arms 17 and 18 being given a rotary movement by a suitable drive device -gear which is not shown in the drawing. The conductors 26 will thereby be twisted together in pairs into two cable parts, which in turn are twisted together as a result of the frame 33 being given a rotational movement. The two pivot arms 17 and 18 can be driven at different speeds, so that the two cable parts will exhibit mutually different twist pitches. Upon energization of the electromagnets 22, the pins 21 are regularly caused to shoot up to deflect a coil holder 2 from each of the circular guide tracks 5 and 6 to the transfer tracks

7 and 8, respectively, which connect these to each other, along which transfer tracks the spool holders 2 and the supply spools 1 on these are transferred to the following of the circular guide tracks, where they are again gripped by a free gripper 19 and moved in rotation along the latter guide track. As a result of this repeated movement of the coils 1 from one circular guide track to the other, both conductors in each cable part will alternate successively along the length of the finished cable. In order to ensure that the deflection of the coil holders 2 from a circular guide track 5 respectively 6 to a transfer track 7 respectively 8 will take place in the desired order, the device must be provided with means that allow energization of the electromagnets 22 only when desired coil holders approach the deflection or change - the connection point between the aforementioned tracks. These bodies can e.g. be arranged to sense the length of the guide pins 4, as indicated by dash-dotted lines in figures 2 and 3 where the length may be different for the different spool holders.

In fig. 4 schematically shows a cable produced according to the description above, which cable consists of four conductors a, b, c and d which are twisted together. As can be seen from this figure, the cable consists of two pairs of conductors with alternating composition along the length of the cable. The cable thus exhibits in the lower section of fig. 4 two pairs formed by conductors a and b, respectively c and d, while corresponding pairs in the middle cable section consist of conductors d and b respectively a and c, and in the upper section of conductors b and c respectively a and d. In fig . 4, for the sake of clarity, the different pairs within h<y>er group are not shown intertwined with each other, which they are, however, in reality.

According to the invention, the relative positions of the conductors and/or groups of conductors are alternated along the length of the cable in such a way that for a given length of the cable the sum of the lengths of the cable pieces along which two arbitrarily chosen conductors in the group, respectively two arbitrarily chosen groups, lie immediately next to each other, almost constantly and independently of how the respective leaders or groups are selected. This means that you can select two arbitrary conductors and/or groups and measure the sub-sections of a given cable length along which these two selected conductors and/or groups lie next to each other, and add up these sub-sections and you then select two others arbitrary conductors and/or groups and measure the sub-sections of the same cable length along which these conductors and/or groups lie next to each other and add up these latter sub-sections, whereby it is found that the sums in both cases are essentially the same. The prerequisite is that the given cable length is sufficiently long, dys. many times longer than the normal distance between immediately following exchange points. With a sufficiently large length, you thus get several sub-sections where two arbitrarily chosen conductors and/or groups lie next to each other. In the cable, cable elements that can be made up of e.g. of a number of single wires or possibly of individual wires, lie in an arbitrary sequence in relation to each other, whereby the relative position of the cable elements in relation to each other varies along the length of the cable.

The device described above can possibly be modified in many different ways for reasons of, among other things, different wishes and goals regarding the structure of the cable, such as e.g. number of leaders in this, which can be chosen arbitrarily large.

When producing a cable consisting of e.g. of five conductors, by means of the above-mentioned device, this can be designed so that the supply coils 1 and the holders 2 for these during the transfer along the tracks 7 and 8 are held in one of these during a twisting moment. Thereby, there is always a supply coil which is located in a transfer track, while the other four supply coils are displaced along = the circular tracks 5 and 6.

When producing a pot according to the invention, it can

in certain cases, it may be necessary to intervene in the manufacturing process in order, after measuring the cross-talk or the capacity between different conductors, to compensate for such imbalances in the cable's electrical characteristics which can be caused e.g. of variations in the thickness of the conductors' insulation. Necessary compensation can thereby be provided by suitably changing the program according to which the leaders are intertwined or intertwined.

As a summary, the following specific advantages of a cable designed according to the invention must finally be mentioned.

No conductors or groups of conductors will lie adjacent to each other along any major combined portion of the cable's length. Thereby, cross-talk between different couples, or between different groups, is greatly reduced. Suitable circuits within a group can be selected in many different ways.

No conductors or groups of conductors are particularly exposed to sheath currents, but such disturbances are distributed equally among all circuits and thereby reduced.

The capacity uniformity of a cable designed according to the invention is significantly better than with previously known cable types, since all conductors, respectively groups of conductors in the cable are completely equivalent.

With a group, respectively cable, consisting of four conductors and constructed according to the invention, a significantly better agreement is achieved between the attenuation values for pair and phantom circuits than with any previously known cable type.

Cross-examination within groups with a different number of managers is eliminated.

Claims (6)

1. Cable, preferably for the transmission of telecommunications signals, comprising a plurality of conductors isolated from each other which are arranged in one or more groups, characterized in that the relative positions of the conductors within at least one group containing at least three conductors, and/ or the relative positions of at least three groups within the cable, alternate along its length in such a way that for a given length of cable in relation to the distance between successive switching points, the sum of the sections along which two arbitrarily chosen conductors within said group, respectively two arbitrarily chosen groups are immediately adjacent to each other, almost constantly and independently of how the relevant leaders, respectively groups, are selected. 2. Method for producing a cable according to claim 1, in which at least three insulated conductors, or groups of such conductors which are each placed on a supply coil or similar, are unwound from the supply coils and brought together into a bundle which is wound on a collection drum, characterized by the fact that in connection with the joining of the conductors, respectively the groups, to the mentioned bundle, the mutual positions of these are switched in such a way that for a given length of cable in relation to the distance between successive switching points, the sum of the pieces along which two arbitrarily chosen leaders within said group, respectively two arbitrarily chosen groups, lie immediately next to each other, almost constantly and independently of how the relevant leaders, respectively groups, are selected. 3. Method according to claim 2, characterized in that the bundled leaders, respectively groups, in connection with the winding on the collection drum, a twist is given about the longitudinal axis of the bundle. 4. Method according to claim 3, characterized in that the aforementioned twisting of the bundle is provided by the collection drum being given a twisting movement in a plane containing the drum's axis of rotation. 5. Method according to one of claims 2 to 4, characterized in that the aforementioned variation of the relative positions of the conductors, respectively the groups, is provided by varying the relative positions of the supply coils during the production of the cable. 6. Method according to one of claims 2 to 5, characterized in that the conductors, respectively the conductor groups, in connection with the joining of these into a bundle are intertwined or twisted into two or more smaller bundles with regularly varying composition during the course of production, whereby the latter bundles together are brought to form the former bundle.