GB2032482A

GB2032482A - A Method and Apparatus for Producing Stranded Wire

Info

Publication number: GB2032482A
Application number: GB7933640A
Authority: GB
Original assignee: Drahtseilwerk Saar GmbH
Current assignee: Drahtseilwerk Saar GmbH
Priority date: 1978-10-19
Filing date: 1979-09-28
Publication date: 1980-05-08
Also published as: LU81587A1; GB2032482B; GR71197B; PT70167A; NO792602L; NL7906390A; IT1123895B; SE7908605L; DE2845487A1; BE878325A; ES484891A1; IT7926580A0; FR2439262A1; BR7906734A; DE2845487C2; FR2439262B1; NL184484C; NL184484B; CH640585A5; DK442279A

Abstract

To increase the filling factor of stranded wire, there is provided a frame (1) of a pressing tool comprising a set of rolling rolls (8) through which the stranded wire (17) is drawn. As a result of a decrease in sliding friction between rolls (8) and the stranded wire (17), the inwardly-directed component of compression force acting on the stranded wire (17) is large compared to the rearwardly- directed component of the compression force acting thereon. Hence, there is a greater increase in the filling factor than would be obtainable without the use of rolls. To achieve a more uniform compression of the stranded wire (17), the frame (1) may be provided with a second pressing tool comprising a set of rolling rolls (6) angularly offset relative to the first pair of rolling rolls. <IMAGE>

Description

SPECIFICATION A Method and Apparatus for Producing Stranded Wire The invention relates to a method of producing stranded wire, for example parallel lay stranded wire, in which the stranded wire is compressed by being passed through a pressing tool.

Furthermore, the invention relates to apparatus for carrying out the method, and to the use of stranded wires produced in accordance with the method, for example in wire rope.

In the production of stranded wire drawing plates or drawing dies are known from wire drawing, are used as the pressing tool. The increase in the filling factor i.e. the proportion of metal in the cross-section, which has been achievable by the use of drawing stones as the pressing tool is limited. For example, in the case of single-ply 1+6 stranded wire which has an original filling factor of 0.77, the increase in the filling factor is limited to around 0.84 to 0.85 and, in the case of a parallel-lay two-ply 1+7(7+7)+14 stranded wire, which has a comparatively high original filling factor of 0.83, the increase in the filling factor is limited to about 0.88. Even upon further compression it is hardly possible to get beyond these limits.

The problem underlying the invention is to increase the compression further.

To solve this problem, the present invention provides a method of producing stranded wire, for example parallel-lay stranded wire, in which the stranded wire is compressed by being passed through a pressing tool, characterised in that, to produce an increased compression, the pressing tool comprises a set of rooling rolls which are arranged in radially-symmetrical manner with regard to one another.

Compressions approaching a filling factor of 1.00 are thereby achievable.

This increase in the filling factor is due to the fact that, with use of drawing plates as the pressing tool, in increasing compression of the stranded wire the proportion of the rearwardlydisplaced material of the stranded wire rises relative to the proportion of the radially inwardly displaced material, and finally the material is no longer displaced inwardly but rearwardly only. In other words the material is no longer compressed.

However, in the employment of the rolling rolls as the pressing tool, as a result of a decrease in sliding friction between the rolling rolls and the stranded wire the compression forces exerted on the stranded wire have a larger component radially inwards as compared with the rearwardlydirected component and in this way the compression of material inwardly is large in comparison with the displacement of material rearwardly. Hence, the greater increase in the filling factor is achieved.

In order to make this ratio as favourable as possible, the rolling rolls can be selected as large as possible, so that the stranded wire contacts them at a correspondingly acute angle, in other words the pressing surfaces are largely turned to one another.

Furthermore, in addition to or instead of drawing the stranded wires through the rolling rolls by means of a draw-off device the rolling rolls can be provided with a drive in order, as a result of the frictional force between the rolling rolls and the stranded wire, to force the material between the rolling rolls.

In addition to this, the relatively slight length stretching of the material has the advatnage that fairly large changes in the properties of the material, in particular the elasticity, are avoided.

This is of considerable importance insofar as such changes in the properties of the material vary between the different wire plies of the stranded wire, but differences in elasticity between the individual wires of a stranded wire have to remain rather limited, so that, with increasing loading, the magnitude of the forces acting on individual wires of the stranded wire does not vary to such an extent that one wire breaks, whilst the others are strained very little. Moreover heating of the material, which used to occur when the pressing tool was in the form of drawing plates, is abolished as a result of the decrease in sliding friction.

Finally, the rolling rolls in the set can be adjustable radially with regard to one another and thus be drawn apart for the introduction of the stranded wire. This enormously simplifies the introduction of the stranded wire as compared with the threading into a drawing stone.

Preferably the stranded wire is passed successively through two mutually angularly offset sets of rolling rolls. Thus a more uniform compression is achieved and only a few pronounced burrs remain on the stranded wire.

In order if possible to avoid burrs it is advantageous to pass the stranded wire, after it has been through the rolling rolls, additionally through a drawing stone which is preferably rotating. The rotation increases the sliding speed of the stranded wire in the drawing stone, by adding a circumferential movement to the longitudinal movement of the stranded wire in the drawing stone; this reduces the coefficient of friction. Moreover, the stranded wire structure, possibly loosened upon the passage through the rolling rolls, is consolidated once more by rotation.

The stranded wire can, in this way, be compressed at will. A stranded wire having an original filling factor of 0.77 will be compressed to a filling factor of at least 0.88 and a stranded wire having an original filling factor of 0.83 will be compressed to a filling factor of at least 0.89. A stranded wire having an original filling factor from 0.77 to 0.83 will be compressed to corresponding values. Preferably the stranded wire is compressed no matter from what original filling factor, to a filling factor of 0.90 to 0.94, preferably 0.91 to 0.93. In this range it displays a particularly long useful life.

Apparatus for carrying out a method in accordance with the invention accordingly comprises a machine frame having a pressing tool comprising a set of rolling rolls which are arranged in radially-symmetrical manner relative to one another and means for passing stranded wire through the pressing tool so as to be compressed thereby.

Advantageously, the set of rolling rollers comprises 2 or 4 rolling rollers. It is desirable to have the machine frame adjacent a stranding machine.

Somewhat similar apparatus are in principle known, for example for the roll drawing of wires and for the embossing of profiles. In the known devices however a compression of the stranded wire is not effected.

The invention will be described further, by way of example with reference to the accompanying drawing, wherein the single figure is a side view of a preferred embodiment of apparatus for carrying out the method in accordance with the invention, it being understood that the following description is illustrative and not limitative of the scope of the invention.

In the drawing a preferred embodiment of the apparatus comprises a machine frame 1, carrying on three uprights, 2, 3 and 4 a firstrolling roll set 5, a second rolling roll set 5, a second rolling roll set 6 and a drawing plate or drawing die 7 which is mounted for rotation in a housing.

The rolling rolls 8 of the two rolling roll sets 5 and 6 are in each case mounted between two parallel levers 9 which are hinged to brackets 10 of the upright 2 or 3 respectively at 11. The two parallel levers 9 are in each case provided with an abutment 12 for a thrust bolt 13, which penetrates the upright 2 or 3 respectively and is held in a threaded part 14 and is adjustable to set a desired rolling pressure.

In the first rolling roll set 5, two rollers 8 are arranged perpendicularly; in the second rolling roll set 6 they are arranged horizontally.

The drawing plate 7 is driven by a motor 15 by way of a gearing 16.

The apparatus is arranged between a stranding machine and a draw-off device neither of which is shown. From the stranding machine, a stranded wire 1 7 runs in the direction shown by the arrow 18 of the first rolling roll set 5 and the rolling rolls 8 of the second rolling roll set 6, through the upright 3 and finally through the drawing plate 7.

In the first rolling roll set 5, the stranded wire 17 is compressed predominantly in one transverse direction and in the second rolling roll set 6 in the other transverse direction. Burrs compressed by the first rolling roll set 5 are eliminated by the second rolling roll set 6. The second rolling roll set 6 compresses only smaller burrs, which are then removed by the drawing plate 7.

From the drawing it can be seen that the rolling rolls 8 have, at their periphery, a groove profile which corresponds to the desired stranded-wire circumference. Furthermore, the direction of rotation of the drawing stone corresponds with the lay direction of the stranded wire.

Claims

1. A method of producing a stranded wire, for example parallel-lay stranded wire, in which the stranded wire is compressed by being -passed through a pressing tool, chracterised in that, to produce an increased compression, the pressing tool comprises a set of rolling rolls which are arranged in radiallysymmetrical manner relative to one another.

2. A method as claimed in claim 1, characterised in that the stranded wire is drawn through the rolling rolls.

3. A method as claimed in claim 1 or 2, characterised in that, for further increase in the compression, the rolling rolls are at least partly driven.

4. A method as claimed in claim 1, 2 or 3, characterised in that the stranded wire is passed successively through two mutually angularly offset sets of rolling rolls.

5. A method as claimed in any preceding claim characterised in that the stranded wire is passed, after the rolling rolls, through a rotating drawing stone.

6. A method as claimed in any preceding claim, characterised in that a stranded wire having an original filling factor of 0.77 is compressed to a filling factor of at least 0.86 to 0.87.

7. A method as claimed in any preceding claim characterised in that a stranded wire having an original filling factor of 0.83 is compressed to a filling factor of at least 0.88 to 0.89.

8. A method as claimed in any preceding claim characterised in that a stranded wire having an original filling factor between 0.77 and 0.83 is compressed at least to a corresponding filling factor.

9. A method as claimed in claim 6, 7 or 8 characterised in that a stranded wire is compressed to a filling factor of 0.90 to 0.94.

10. A method as claimed in any preceding claim characterised in that the stranded wire is compressed to a filling factor of 0.91 to 0.93.

11. Apparatus for carrying out the method claimed in any preceding claim comprising a machine frame having a pressing tool comprising a set of rolling rolls which are arranged in radiallysymmetrical manner relative to one another, and means for passing a stranded wire through the pressing tool so as to be compressed thereby.

12. Apparatus as claimed in claim 11 characterised in that the machine frame is adjacent a stranding machine.

13. Apparatus as claimed in claim 11 or 12 characterised in that the pressing tool comprises a second set of rolling rolls which is angularly offset with regard to the first set of rolling rolls, and through which the stranded wire can be passed.

14. Apparatus as claimed in claim 11, 12 or 13 characterised in that from the second set of rolling rolls the stranded wire is passed through a drawing plate.

1 5. Apparatus as claimed in any preceding claim characterised in that the drawing plate is rotatabie.

16. Apparatus as claimed in any preceding claim comprising a draw-off device.

1 7. Apparatus as claimed in any preceding claim characterised in that the or each rolling roll set are provided with a drive.

18. Apparatus as claimed in any preceding claim characterised in that the or each set of rolling rolls have 2 or 4 rolling rolls.

1 9. Apparatus as claimed in any preceding claim characterised in that the rolling rolls in the or each set are adjustable radially relative to one another.

20. Use of a stranded wire, produced in accordance with the method of any of claims 1 to 7, to produce a wire rope.

21. Apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.

22. A method of producing stranded wire substantially as hereinbefore described with reference to the accompanying drawing.

23. Stranded wire produced by the method of any of claims 1 to 7 or claim 1 7.

24. A wire rope incorporating the stranded wire claimed in claim 18.