DE2355624A1 - METHODS TO REDUCE ELECTRICAL COUPLINGS IN MESSAGE CABLES - Google Patents

Description

Method for reducing electrical coupling. in e-communication cables

In the manufacture of symmetrical communication cables, i.e. cables whose cable cores are stranded in pairs or fours Cores are built up, is usually already during the stranding process an electrical decoupling of the transmission circuits formed from the wires is carried out. This is mainly done with the help of different twist for the individual stranding units such as pairs or fours as well as for the stranding groups formed from these stranding units such as bundles or stranding layers and also through changes in twist during the stranding of the stranding units or stranding groups.

These measures to reduce the electrical coupling are also used in the so-called SZ stranding is used, in which stranding elements alternate with a left-hand twist in successive longitudinal sections (S-twist) and a right-hand twist (Z-twist). at Stranding of this type, the stranding elements to be stranded run off stationary pay-off racks, with further processing the SZ stranding units formed from the stranding elements can be connected in the same operation. In general, two stranding processes previously carried out separately, but in particular the stranding of cores, are involved Pairs or star fours and the stranding of the pairs or star quads into a basic bundle in a single operation summarized.

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To carry out the recently developed SZ stranding are used in dex * as a rule, revolving stranding devices that one Cache included. In this case, buffers with fixed memory contents can be used, those with section by section rotate with changing speed or direction of rotation, while the throughput speed of the stranding elements is constant. The buffers with fixed memory contents can also be used with constant speed and direction of rotation, while the throughput speed of the stranding elements in sections will be changed. Another possibility is to change the memory content while the rotary movement of the intermediate memory remains constant to increase or decrease alternately. It is also known to work with fixed buffers, which are flown around by wire brackets. In addition, SZ stranding methods are known in which, instead of intermediate stores is worked with stranding heads, which are guided within the stranding device in a stretched state Enclose the material to be stranded from the outside in a non-positive manner, whereby at intervals either the rotary movement, the local position or the frictional connection of one or more stranding heads or the throughput speed of the material to be stranded or the length of the length formed between the stranding heads and the associated stranding points Stranding sections are changed at intervals (magazine "Draht" 22 (1971), issue 9, pages 619/625). All of these known The common SZ stranding process is that one odex several which determines the lay length of the manufactured SZ stranding units Process variables, for example speed or direction of rotation of the stranding device or take-off speed the stranding elements or the rate of change of the memory content, is changed or reversed at intervals.

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In order to use the It has already been proposed to reduce electrical coupling (German Auslegeschrift 2 213 693), the lay lengths s the SZ stranding and / or the distance T between the reversal points of the Twist direction constantly changing, with this change should be at least $ 0.5 of size (- + - ^). There the lay length s is usually about two orders of magnitude smaller than the distance T between the twist change points relatively large for stranding with a constant echo length s Changes to the distance T of the twist change points are necessary.

The invention is also based on the object Communication cables, the cores of which are stranded to form SZ stranding units reduce the electrical coupling. In order to achieve this object, however, the invention takes a different approach. The invention is based on a · method in which the Reduction of the electrical coupling by influencing the stranding process in the same operation two-stage stranding of cores to form stranding units and of stranding units to form stranding group, with the strands closed Stranding units with alternating twisting directions at intervals T, which are continuously changed during stranding are stranded and here within a section of constant twisting direction constant different from one another Get lay lengths ε .., Sp ... ß, and where a Number Z of such stranding units stranded to form a stranding group will. According to the invention, the distance T of the reversal parts becomes the twist direction within a range T to (T + I *) continuously enlarged and reduced, where T .. is at least as big as the size

^ß n · ^s m '■ "

² · < ⁸ n ^{+ s} m>

with η not equal to m and n, m = 1 ... Z.

With regard to the envisaged within the scope of the invention

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Modulation of the distance between the reversal points of the twist direction the invention is based on the knowledge that the couplings occurring between adjacent stranding units do not arise at discrete points in the longitudinal direction of the stranding units, but that the stranding units unite have so-called coupling coating, with which the continuous distribution of the couplings over the length is referred to. This coupling coating, the integral of which gives the respective couplings, is now not uniform over the length of the stranding elements distributed, but rather follows a sin or cos function with the period duration as a first approximation

S ₁ S ₂
P = ö — ττ— j where s., And s _{o are} the lay lengths of the two

fa Ji T Sp I C.

are each considered stranding units. The coupling— integral of a section of length 1 accordingly follows a law

K = K ₀ . are (2 IC. 1 5 ^ 7-sf ⁺ * o>

In the case of SZ stranding with constant -twist change intervals I = T, there are now residual couplings in each S or Z section of length T, which, depending on the initial phase # ( _0, lie between ο and - K _Q. These residual couplings have in all successive S-sections have the same amplitude and the same sign and therefore add up in proportion to their length. The same applies to the behavior of the Z-sections with one another.

In the measure provided within the scope of the invention, which provides for a constant variation of the distance between the reversing parts, it is now ensured that the residual couplings occurring in each S or Z section have opposite signs, which leads to a subtraction of the residual coupling and thus to a reduction in the total coupling. The special advantage

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part of this measure is to be seen in the fact that the reduction electrical couplings with relatively small changes the distance between the reversal points is achieved.

In the context of the invention, it has proven to be particularly expedient to continuously increase and decrease the distance T of the reversal points of the twisting direction in a equally large steps of width Δ Τ or to let the distance T become larger or smaller in a equally large steps and after
Reaching the upper or lower limit value to jump back to the other limit value, whereby the step width

ss
Δ Τ is smaller or larger than the quantity η · ^ ·.

^B n ^{+ s} m
The larger the tfert a is chosen, the better it is

with the variation of the distance achieved decoupling of the verses units.

By varying the distance between the reversal points
To further improve the decoupling effect achieved in the twisting direction, it is expedient that a-times the step width Δ T is equal to or approximately equal to e-times

ss
of size "■ · - & ■ , where a and e are integers and

^s n ^{+ s} .m.

a not equal to 1 applies.

A particularly effective decoupling of the stranding units can be achieved if the step width A T is equal to or
approximately equal to half the period of the coupling coating, i.e. equal to or approximately equal to the size

..— - , choose. In this case, the coupling

² K ^{+ s} m> ₇

integral with constant amplitude of an S resp.

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Z-section to the next in each case the sign.

As already mentioned, "the stranding groups formed during the production of communication cables always consist of several, in particular five, stranding units such as star fours However, in order to obtain sufficiently small systematic couplings for all stranding units within the stranding group, the lay lengths of the stranding units are expediently chosen in such a way that the coupling period η. m with the step width / \ T over-

^B n ^{+ s} m

agrees. A sufficiently large number a of stages in the modulation process then ensures that the sign of the residual couplings in the various S and Z sections change continuously and thus the compensation effect achieved occurs.

The new method for decoupling the stranding units from communication cables can be used with different SZ stranding techniques be applied. Particularly suitable for this, however, is SZ stranding with constantly rotating intermediate stores, whose Memory contents can be reduced and enlarged alternately. It is recommended that the intermediate storage units rotate at different speeds from one another and that their storage contents is synchronously decreased and increased alternately, the variation of the distance T being effected by the times of the Memory content reduction or enlargement within a Range t to (t + t ..) continuously become smaller and larger. In order to carry out this measure, the German Offenlegungssehrift 1 941 611 described SZ-Verseilvor-

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Direction suitable for stranding cores to form a stranding unit, which contains two intermediate storage units arranged one behind the other, their storage contents changing in opposite directions, rotating at different speeds and each consisting of two roller groups, the second roller group of the first intermediate storage unit and the first roller group of the second intermediate storage unit are rotatably mounted in a frame that runs uniformly back and forth in the direction of the stranding axis with a minimal stroke movement b. To carry out the new method with such a device it is provided in a further development of the invention that the lifting movement of the frame at a distance of 0.5. (b + r. Δ Xr) or - 0.5. (b + r. Ab) is reversible with respect to the 'middle position, the number r after each complete back and forth movement by' one jumping successively assumes the values 0, 1, 2, 3 to a and then jumps back to zero. . . .

The variation in the stroke movement of the frame and therefore the variation the distance between the reversal points of the twisting direction expediently takes place with the aid of a length pulse generator and one Pulse counter which is sent to the reversing device of the frame act. For this purpose, the length pulse generator is designed in such a way that that it is per unit length of a stranding unit to be produced emits a voltage pulse. The pulse counter is designed in such a way that it records the length pulses of the pulse generator only counts when the frame, which can be moved to and fro, from * its center position is at a distance of + 0.5 b or - 0.5 b and that he has traveled in successive stages after each O, 1, 2, 3 ... a pulses the reversal of the stroke

..- / ■ - controls the movement of the frame. . ·.

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A numerical example is given below to explain the new decoupling method. A diagram that schematically, the relationships on an SZ stranding unit produced using this example are illustrated in the figures 1 and 2 reproduced.

It is assumed that the decoupling measure in a stranding process is carried out, with the 20 wires to 5 star fours and in the subsequent operation these 5 star quads be stranded into a basic bundle. The stranding of the cores to the stranding units takes place according to claim 6 in each case with two buffers arranged one behind the other, the contents of which are varied in opposite directions.

The individual for stranding and to reduce the electrical Couplings to be considered are selected as follows:

1. Lay lengths of the ζ = 5 stranding units S ₁ = 100 in Sp = 110 mm s ~ = 120 mm

s. = 130 mm Sr = ^ AfO mm

Based on these lay lengths, the following coupling periods p are obtained:

ρ 52.5 mm

^ medium 60.0 mm 67.5 mm

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2) Distance and variation of the reverse parts of the twist direction

T ₀ = 4- m.

T = 30 mm, with the number of variation steps each reversal parts of the twist direction and thus on each reversal point of the reciprocating frame 16 is. The number a of levels is then 32. From this surrendered

T .. = 960 mm. This fourth is according to claim 1 greater than the half value of the maximum coupling period. With regard to what is described in DT-AS 2 213 693 Method can be calculated that due to the intended variation of the distance between the reversal points, the sums d + a and d - a can be varied by less than 0.57 *.

Pig. 1 initially shows schematically a stranding unit V, whose twisting direction changes in sections. The distances between the reversal points of the twist direction are with the Value T given. Such a stranding unit would be obtained if you see the reversal points of the SZ stranding and moveable frame would not vary.

Pig. 2 shows a schematic representation of a stranding unit V-j, in which the distance between the reversal points is gradually increased by the value AT at each reversal point.

2 figures ■

7 claims

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Claims (7)

VPA 73/4739 - 10 - claims 1. Method for reducing electrical coupling in. Specialist cables. · by influencing the stranding process in the same Two-stage stranding of cores to .setting units and of stranding units to .setting group, in which the cores to stranding units alternating at intervals T, which are continuously changed during stranding Twisting direction are stranded and here within a section of constant twisting direction constant, different lay lengths s-, Sp, ... s, and in which a number ζ of such stranding units is stranded to form a stranding group, characterized in that. that at each reversal part of the twisting direction, the distance T of the reversal parts within a range T to (T _Q + T ^) is continuously increased and decreased, where T ^ is at least as large as the size ^s n · ^s m with_n_ not equal to m and. . . . η, ra = 1 .; .ζ. 2. The method according to claim 1, characterized in that * * the distance ϊ of the reversal points of the twisting direction in a equally large steps of width Δ Τ is continuously increased and is reduced or that the distance T is larger or smaller in a steps of the same size and after reaching the upper one -11- 50 9820/0 539 VPA 73/4739 - 11 - or lower limit value jumps back to the other limit value, the step width Δ Τ being smaller or larger than the size ^s n - ^s m
⁸ n ^{+ 8} m 3. "The method according to claim 2, characterized in that the a times the step width Δ T is the same or approximately the same s * s e times the size ■, where a and e are integers ■. ^s n ^{+ s} m. and a is not equal to 1. 4. The method according to claim 3, characterized in that the step width Δ T is equal to or approximately equal to the size ^s n · ^s m .
² * t ^s n ⁺ V 5. The method according to any one of claims 1 to 4, characterized in that that the variation of the distance T with the help of Intermediate storage takes place, which rotate at a constant, mutually different speed, whereby the memory contents the buffer memory is alternately reduced and reduced in size are increased by the times of the memory content reduction or enlargement within a range t to (t + t ..) keep getting smaller and bigger. 6. Apparatus for performing the method according to claim 5, each for stranding wires to form a stranding unit two arranged one behind the other, their memory contents opposite contains changing, with different speeds rotating intermediate storage, each of two Role groups exist, the second role group of the first buffer and the first roller group of the second 509820/0539 - 12 - VPA 73/4739 - 12 - Intermediate storage is rotatably mounted in a frame that moves uniformly back and forth in the direction of the stranding axis with a minimal stroke movement b,
characterized, that the lifting movement of the frame is at a distance of + 0.5. (b + r. A ^)) or -0.5. (b + r. A b) is reversible with respect to the middle position, whereby the number r takes on the values O, 1, 2, 3, up to a one after the other after each complete back and forth movement, jumping back to O and then jumps back to O. 7. The device according to claim 6, which has a length pulse generator, which emits a tension pulse per unit length of a stranding unit to be produced and contains a pulse counter, characterized by a pulse counter that counts the pulses of the length encoder counts down after the frame from the center position from the distance + 0.5 b or - 0.5 b has traveled, and after 0,1,2,3 ... a pulses the reversal of the Lifting movement of the frame 'controls'. 509820/0539