GB1586821A

GB1586821A - Cables

Info

Publication number: GB1586821A
Application number: GB4093277A
Authority: GB
Original assignee: Phillips Cables Ltd
Current assignee: Phillips Cables Ltd
Priority date: 1976-12-08
Filing date: 1977-10-03
Publication date: 1981-03-25
Also published as: CA1079503A

Description

(54) IMPROVEMENTS RELATING TO CABLES (71) We, PHILLIPS CABLES LIMITED, of King Street West, Brockville, Ontario K6V 5W4 Canada, a Canadian company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a cross-stranding machine and a method which is particularly useful in the production of telephone cables.

The invention also includes within its scope a cable when formed in such a machine or by such a method.

The production of twisted cables usually requires the utilization of a machine by which a multiplicity of wires or twisted groups of wires are fed into a die. The die forms the cable to the required core diameter and round configuration.

The individual wires or twisted groups of wires fed to the die normally are fed through holes in a guide plate, from individual spindles or other wire feeding apparatus.

Either the plate or a twisting die (if used) oscillates about its axis to provide periodic reversing of the direction of stranding.

Transposition of the wires or pairs rather than continuous twisting in a single direction is required in order to reduce the capacitance between wires or pairs, which capacitance can cause crosstalk or imbalance.

The present invention is directed to a cablestranding machine in which the noted transposition of wires can be obtained.

The invention provides a cross-stranding machine comprising: a guide plate, oscillatorily rotatable about an axis, having a separate guide for guiding, in use of the machine, each of at least three strands so that they traverse the guide plate orthogonally: a forming die for forming said strands into a cable, placed downstream of the guide plate; and a first and a second roller located between the guide plate and the die, the top surface of the first roller being positioned so as, in use of the machine, to relatively bias all the strands outwardly from a line joining the axes of the guide plate and the die, and the bottom surface of the second roller being positioned so as, in use of the machine, to relatively bias the strands in a direction opposite to the bias of the first roller after they leave the top surface of the first roller.

The rollers preferably have their axes substantially perpendicular to said line.

The invention also relates to a method of forming a cable, said method comprising drawing a multiplicity of strands, each through a separate guide in a rotationally oscillating guide plate, over the top surface of a first roller and under the bottom surface of a second roller and through a cable-forming die, the top surface of said first roller being positioned so as to relatively bias all the strands outwardly from a line joining the axes of the guide plate and the die, and the bottom surface of the second roller being positioned so as to relatively bias all the strands in a direction opposite to the bias of the first roller after they leave the top surface of the first roller.

Each strand may comprise a pair of wires.

While previously proposed apparatus provides stranding of the wires, such prior art apparatus often results in mutual capacitance values of fairly wide variation. This is believed to result from wires or pairs lying adjacent to the same group of wires or pairs throughout the cable length. The present invention provides mutual capacitance values of consistently closer grouping than if stranded by the prior art apparatus, which close grouping is an important attribute of the consistency of the resulting cable. The improved cable results from the imposition of the aforenoted roller between the oscillating guide plate and the die, which rollers retain the wires in relative position more accurately, following transposition by the oscillating guide plate.

It is intended that the word "wire" in this specification denotes not only single strands of wire, but also twisted pairs.

A better understanding of this invention will be obtained by reference to the following description of an examplary embodiment of the invention, and to accompanying diagrammatic drawings, in which: Figure 1 is a schematic view in perspective of the basic elements of the machine; Figure 2 is a side elevation of the machine in Figure l; Figure 3 depicts the face plate orientation and resulting wire locations on the surface of the first roller; and Figure 4 depicts a section of a three wire cable produced by the machine.

Turning first to Figure 1, a guide plate 1 contains a multiplicity of apertures 2, equidistant from the centre of rotation of the guide plate 1, and preferably with guide eyelets (not shown) through which are drawn wires 3 so that they traverse the guide plate 1 orthogonally. It should be noted that apertures 2 serve as guides, and other kinds of guide means may be provided, such as wire loops, etc. The formation of a three wire cable is shown.

A die 4 is provided, through which the wires 3 pass, which forms the wires into a cable. Upon leaving the die the cable can be wound upon a spool, or can be passed to succeeding processing stages.

Located between the die 4 and the guide plate 1 are a pair of rollers 5 and 6. The rollers are located so that the wires pass over the top surface of the first rdller 5 and under the bottom surface of the second roller 6; the axes of the rollers are preferably substantially perpendicular to a line joining the axes of the guide plate and the die, or approximately transverse to the wires.

'The'top surface of the roller 5 is positioned so that all the wires are biased outwardly 'from said line, and the bottom surface of the rdller 6 is positioned so that all the wires are biased in the opposite direction -after they leave the top surface df;the first roller.

This structure can be seen more clearly in side elevation in Figure 2. The wires 3 all pass over the top -of roller 5 and under the bottom of roller 6 and into die 4, from which they emerge as a three wire cable.

Bach of the wires can be twisted pairs of Wires, and be treated in similar fashion to a single strand, in order that cables with a larger count of wires may be fabricated.

in operation, the guide plate 1 is rotatably oscillated through a minimum of 90 in either direction. Each ofthe wires is thus displaced relative to the other, and rollers 5 and 6 serve to securely maintain the relative displaced positions. When the die forms the three wires into a cable, their sequence of positions which would ordinarily be similar along the length of the cable will be displaced in accordance with the oscillation of guide plate 1.

A drive means such as an oscillating motor driven gear:train can be coupled to the guide ;pláte to effect the oscillation. The design of the drive means is presumed to be within the expected skill df someone skilled in the art, as it can be of conventional design.

For a better understanding of the mecha nism of transposition, reference is now made to Figure 3. Guide plate 1 contains three apertures labelled as A, B, and C. As the wires pass over roller 5, the rollers stabilize them in positions shown by the three wires in section, with wire A in the middle, wire B to the left and wire C to the right.

Guide plate 1 is then rotated,say, through 1200 clockwise. Wire B then takes the central position, wire C the left-hand position and wire A the right-hand position.

The guide plate may then be rotated counterclockwise until it achieves a position 1200 counterclockwise of the central position, whereupon wire C takes the centre position, wire A the left-hand position and wire B the right-hand position.

Figure 4 shows a cable in section as it emerges from the die 4, at various points in time. In the first cable position at the left, the first point in time, wire A is central and wires B and C to the lower left and right respectively, all spaced 1200 from each other with respect to the cable axis. Since the wires are being twisted clockwise, once a 1200 twist is effected, wire B will have rotated to the central position and wires C and A to the lower left and right-hand positions respectively. A further 1200 twist clockwise will bring wire C to the central position and wires A and B to the lower left and right-hand positions respectively, and a further 1200 twist clockwise brings the wire locations back to their initial positions as shown at the extreme right hand position.It.should be noted that after a predetermined number of turns, the wires will be rotated counterclockwise in order to facilitate continuous running, as described earlier.

The imposition of the pair of roller has been found to improve the positioning of the wires prior to entering the die, resulting in what is believed to be a more precise positioning of the transposition points. The initial capacitance has been found to be consequently decreased and of closer -grouping than the prior art cabling apparatus, without the rollers.

WHAT WE CLAIM IS 1. A cross-stranding machine comprising: (a) a guide plate, oscillatorily rotatable about an axis, having a separate guide for guiding, in use of the machine, each of at least three strands so that they traverse the guide plate orthogonally; (b) a forming die for forming said strands into a cable, placed downstream of the guide plate; and (c) a first and a second roller located between the guide plate and the die, the top surface of the first roller being positioned -so as, in use of the machine, -to relatively bias all the strands outwardly from a line joining the axes of the guide.plate and the die, and the bottom surface of the second -roller being -positioned so as, in use of the machine, to relatively bias the strands in a direction oppo

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Figure 2 is a side elevation of the machine in Figure l; Figure 3 depicts the face plate orientation and resulting wire locations on the surface of the first roller; and Figure 4 depicts a section of a three wire cable produced by the machine. Turning first to Figure 1, a guide plate 1 contains a multiplicity of apertures 2, equidistant from the centre of rotation of the guide plate 1, and preferably with guide eyelets (not shown) through which are drawn wires 3 so that they traverse the guide plate 1 orthogonally. It should be noted that apertures 2 serve as guides, and other kinds of guide means may be provided, such as wire loops, etc. The formation of a three wire cable is shown. A die 4 is provided, through which the wires 3 pass, which forms the wires into a cable. Upon leaving the die the cable can be wound upon a spool, or can be passed to succeeding processing stages. Located between the die 4 and the guide plate 1 are a pair of rollers 5 and 6. The rollers are located so that the wires pass over the top surface of the first rdller 5 and under the bottom surface of the second roller 6; the axes of the rollers are preferably substantially perpendicular to a line joining the axes of the guide plate and the die, or approximately transverse to the wires. 'The'top surface of the roller 5 is positioned so that all the wires are biased outwardly 'from said line, and the bottom surface of the rdller 6 is positioned so that all the wires are biased in the opposite direction -after they leave the top surface df;the first roller. This structure can be seen more clearly in side elevation in Figure 2. The wires 3 all pass over the top -of roller 5 and under the bottom of roller 6 and into die 4, from which they emerge as a three wire cable. Bach of the wires can be twisted pairs of Wires, and be treated in similar fashion to a single strand, in order that cables with a larger count of wires may be fabricated. in operation, the guide plate 1 is rotatably oscillated through a minimum of 90 in either direction. Each ofthe wires is thus displaced relative to the other, and rollers 5 and 6 serve to securely maintain the relative displaced positions. When the die forms the three wires into a cable, their sequence of positions which would ordinarily be similar along the length of the cable will be displaced in accordance with the oscillation of guide plate 1. A drive means such as an oscillating motor driven gear:train can be coupled to the guide ;pláte to effect the oscillation. The design of the drive means is presumed to be within the expected skill df someone skilled in the art, as it can be of conventional design. For a better understanding of the mecha nism of transposition, reference is now made to Figure 3. Guide plate 1 contains three apertures labelled as A, B, and C. As the wires pass over roller 5, the rollers stabilize them in positions shown by the three wires in section, with wire A in the middle, wire B to the left and wire C to the right. Guide plate 1 is then rotated,say, through 1200 clockwise. Wire B then takes the central position, wire C the left-hand position and wire A the right-hand position. The guide plate may then be rotated counterclockwise until it achieves a position 1200 counterclockwise of the central position, whereupon wire C takes the centre position, wire A the left-hand position and wire B the right-hand position. Figure 4 shows a cable in section as it emerges from the die 4, at various points in time. In the first cable position at the left, the first point in time, wire A is central and wires B and C to the lower left and right respectively, all spaced 1200 from each other with respect to the cable axis. Since the wires are being twisted clockwise, once a 1200 twist is effected, wire B will have rotated to the central position and wires C and A to the lower left and right-hand positions respectively. A further 1200 twist clockwise will bring wire C to the central position and wires A and B to the lower left and right-hand positions respectively, and a further 1200 twist clockwise brings the wire locations back to their initial positions as shown at the extreme right hand position.It.should be noted that after a predetermined number of turns, the wires will be rotated counterclockwise in order to facilitate continuous running, as described earlier. The imposition of the pair of roller has been found to improve the positioning of the wires prior to entering the die, resulting in what is believed to be a more precise positioning of the transposition points. The initial capacitance has been found to be consequently decreased and of closer -grouping than the prior art cabling apparatus, without the rollers. WHAT WE CLAIM IS

1. A cross-stranding machine comprising: (a) a guide plate, oscillatorily rotatable about an axis, having a separate guide for guiding, in use of the machine, each of at least three strands so that they traverse the guide plate orthogonally; (b) a forming die for forming said strands into a cable, placed downstream of the guide plate; and (c) a first and a second roller located between the guide plate and the die, the top surface of the first roller being positioned -so as, in use of the machine, -to relatively bias all the strands outwardly from a line joining the axes of the guide.plate and the die, and the bottom surface of the second -roller being -positioned so as, in use of the machine, to relatively bias the strands in a direction oppo

site to the bias of the first roller after they leave the top surface of the first roller.

2. A cross-stranding machine as defined in Claim 1, in which said rollers have their axes substantially perpendicular to said line.

3. A cross-stranding machine as defined in Claim 1 or Claim 2, further including drive means coupled to the guide plate for rotating the guide plate clockwise and counterclockwise through a minimum of 90" in either direction.

4. A cross-stranding machine as defined in any one of the preceding claims in which the guides are comprised of eyelets located in holes in the guide plate, equidistant from the centre of rotation of the guide plate.

5. A cross-stranding machine construc- ted, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated in, the accompanying diagrammatic drawings.

6. A method of forming a cable, said method comprising drawing a multiplicity of strands, each through a separate guide in a rotationally oscillating guide plate, over the top surface of a first roller and under the bottom surface of a second roller and through a cable-forming die, the top surface of said first roller being positioned so as to relatively bias all the strands outwardly from a line joining the axes of the guide plate and the die, and the bottom surface of the second roller being positioned so as to relatively bias all the strands in a direction opposite to the bias of the first roller after they leave the top surface of the first roller.

7. A method of forming a cable as defined in Claim 6, wherein each strand comprises a pair of wires.

8. A method of forming a cable, said method being substantially as hereinbefore described with reference to the accompanying diagrammatic drawings.

9. A cable which has been formed in a cross-stranding machine according to any one of Claims 1 to 5, or by a method according to any one of Claims 6 to 8.