EP3775367B1 - Stranding machine - Google Patents

Description

The present invention relates to a stranding machine for producing a strand from a plurality of wires. In the stranding machine, several such wires are stranded together by twisting, i.e. processed into a strand. The wires are preferably made from a copper alloy, particularly preferably from a copper-magnesium or copper-tin alloy, for example with a proportion of 0.2 or 0.3% magnesium or tin, or also preferably from a copper-silver alloy.

A stranding machine of the type in question has a stranding device for stranding the wires.

Preferably, the stranding device has a rotating rotor which has an elongated rotor bracket which is curved radially outwards and is rotatably mounted at both ends. The majority of the wires are fed to the rotor and guided over the rotor bracket, whereby the wires are twisted at one or more stranding points.

Preferably, the stranding machine has a rotatably mounted pull-off disk for pulling the strand from the stranding device. Preferably, the pull-off disk is driven in order to generate the required tension for pulling the strand.

After the strand has been pulled off the stranding device, the strand is preferably wound onto a spool using a suitable winding device or is processed further directly. If the strand is wound onto a spool, this generally has a cylindrical spool core for winding the strand and a disc-shaped flange at each end of the spool core to prevent the windings from slipping off the spool core. While the strand is being wound onto the spool, the spool generally rotates around the longitudinal axis of the spool core (hereinafter referred to as the "spool axis").

Particularly in the case of stranding machines of the type described above with a rotor bow, which are operated as double-twist stranding machines, the take-off disk and possibly also the winding device and the spool for winding the strand are preferably arranged within the rotation volume of the rotor bow, i.e. within the space around which the rotor bow rotates. Therefore, only a limited amount of space is available for the take-off disk, the winding device and/or the spool. The spool axis can be arranged essentially at a right angle to the rotor axis, essentially parallel to the rotor axis or at another angular position relative to the rotor axis. The strand preferably emerges from the rotor along the rotor axis.

The problem with the manufactured strand is that it can have a twist. In addition, the strand tends to bend, "curl" and "roll over" when not under load, ie to form loops.

This is problematic during further processing of the stranded wire, especially when winding it onto a spool, when assembling it and when crimping, i.e. when clamping connectors onto the stranded wire.

This also makes extrusion more difficult, i.e. the casting of plastic insulation around the strand in an extrusion process. In particular, the phenomena mentioned during extrusion hinder the use of so-called bag extrusions, which work continuously, instead of rotating tangential extrusions, which do not work continuously and only allow a much lower feed rate of the strand.

Finally, the twist and the tendency of the strand to "curl" reduce the possible number of bending cycles, i.e. the number of bending cycles that can be carried out without material fatigue or failure.

From the EN 26 11 938 A1 is a device for twisting threads, in particular wire ropes or strands, with a friction disk mounted between two guides of the unwinding thread so as to be freely rotatable about an axis adjustable at an angle to the guide path, with a circumferential groove widening from the inside to the outside, the flanks of which form contact surfaces for the thread in variable diameter ranges. At least one of the guides can be arranged so as to be adjustable transverse to the direction of the thread's unwinding, so that the thread within the guide path can be additionally influenced and, in addition to the twisting, a straightening effect can also be exerted, for example.

A stranding machine according to the preamble of claim 1 is known from DE102015001430 A1 known.

It is the object of the present invention to provide a stranding machine and a method for producing a strand such that the strand produced has at most a slight twist and a slight tendency to "curl".

This object is achieved by the stranding machine and the method for producing a strand according to the independent claims. Advantageous embodiments of the invention are contained in the dependent subclaims.

The invention is based on the observation that the twist and the tendency of the strand to "curl" can be reduced by a movement in the direction of the torsion of the strand resulting from the stranding, hereinafter referred to as "strand torsion", preferably in conjunction with a stretching of the strand, ie a stretching which leads to a plastic deformation of the strand.

In the stranding machine according to the invention and the method according to the invention for producing a strand, at least one measure is therefore implemented which takes this observation into account.

A stranding machine according to the invention has at least one rotatably mounted deflection roller for deflecting the strand and at least one guide device for guiding the strand, wherein the guide device is arranged such that the strand can be guided in a straight line from the guide device to the deflection roller in such a way that the strand is pressed against a first flank of the deflection roller.

The deflection roller has a standard design, with the running surface for the strand on the front face of the deflection roller having a wedge-shaped depression in cross section. This wedge-shaped depression has a first and a second flank that is directed radially inwards at an angle to the center plane of the deflection roller. The area near the inner edges of the two flanks, where the radius of the running surface is smallest, is called the roller base.

When the strand is deflected by the deflection roller, it moves from the first flank of the deflection roller into the base of the roller on its way from the entry point to the exit point. In other words, the strand "slides" down the first flank into the base of the roller. The strand experiences a movement that occurs with or against the strand torsion. By selecting the first flank from the two flanks of the running surface of the deflection roller accordingly, it can be achieved that the strand moves with the strand torsion, which reduces the tendency of the strand to "curl".

In a preferred embodiment of the invention, a pulling device is additionally arranged behind the deflection roller in the direction of movement of the strand, which is suitable for exerting a pulling force on the strand running off the deflection roller. This causes the strand to stretch, ie Stretching, which leads to a plastic deformation of the strand, which also reduces the tendency of the strand to "curl".

Preferably, the pulling device is a winding device. Such a winding device is already provided in many stranding machines in order to wind up the strand produced. The winding device can be used to exert the desired pulling force on the strand running off the deflection roller, in particular by means of a driven spool axis in the winding device.

In a further preferred embodiment of the invention, a strand contact point on the guide device, from which the strand can be guided in a straight line to the deflection roller in such a way that the strand is pressed against the first flank of the deflection roller, is offset from the center plane of the deflection roller. As a result, the strand runs off-center onto the deflection roller and is thus automatically pressed against the first flank of the deflection roller without the need for an additional pressing device.

According to the invention, the guide device is arranged in such a way that the strand can be guided in a straight line from the guide device to the deflection roller in such a way that the strand is pressed against a second flank of the deflection roller that is different from the first flank. The strand is thus pressed either against the first or against the second flank of the deflection roller. This selection can be made depending on the lay direction of the strand, i.e. the direction in which the individual wires are twisted together during stranding and on which the strand torsion also depends. A distinction is made here between the so-called S-lay, in which the wires are wound around each other anti-clockwise, and the so-called Z-lay, in which the wires are wound around each other clockwise, whereby this property is invariant with respect to the direction in which the strand is viewed.

According to the invention, the guide device is movable relative to the deflection roller, in particular essentially perpendicular to the center plane of the deflection roller. In this way, the strand contact point on the guide device can be set precisely relative to the deflection roller. According to the invention, this also makes it possible to select the flank of the deflection roller against which the strand is to be pressed.

In addition, the selection of the flank of the pulley against which the strand is to be pressed can also be made by guiding the strand around on different sides of the guide device.

In a further preferred embodiment of the invention, the guide device is a rotatably mounted guide roller. This allows the friction of the strand against the guide device to be reduced.

The invention further relates to a method for producing a strand from a plurality of wires, carried out on a stranding machine according to the invention. In the method, the wires are stranded in the stranding device, the strand is guided from the stranding device to the guide device, the strand is guided in a straight line from the guide device to the deflection roller in such a way that the strand is pressed against the first flank of the deflection roller, the strand is deflected by the deflection roller, and the strand is guided away from the deflection roller.

When deflected by the deflection roller, the strand preferably moves from the first flank into the roller base of the deflection roller.

By guiding the strand in this way, the twist and the tendency of the strand to "curl" are reduced due to the mechanisms described above.

An advantageous embodiment of the invention is shown in the accompanying drawing in conjunction with the following description.
Fig.1 a perspective view of a section of a stranding machine according to the invention with the course of the strand.

In Fig.1 the course of the strand 1 is shown by a stranding machine according to the invention, which in the exemplary embodiment is preferably a double-twist stranding machine. The stranding machine has a stranding device in which a rotor with a rotor bracket (not shown) rotates. Inside the rotation volume of the rotor bracket, a housing 2 is suspended at its left and right ends by means of two rotor shaft bearing housings on two separate rotor shaft sections (both not shown).

The strand 1 runs through an opening 3 in the housing 2 to a driven pull-off disk 4, which pulls the strand 1 off the stranding device by applying a tensile stress. The pull-off disk 4 and a lifting roller 5 arranged above the pull-off disk 4 and parallel to it each have a plurality of grooves through which the strand 1 is alternately guided, so that the strand 1 alternately runs through the pull-off disk 4 and the lifting roller 5 several times in total. The pull-off disk 4 and the lifting roller 5 function as a first torsion lock.

The strand 1 then passes through two deflection rollers 6 and 7 and is deflected by a total of 270 degrees. The deflection roller 7 is slightly angled so that the strand running off the deflection roller 7 does not collide with the strand running onto the deflection roller 6.

The strand 1 then runs along one side - in the example on the left - of a rotating guide roller 8, the axis of which runs approximately vertically. The guide roller 8 causes the strand 1 to be slightly deviated from its path. is deflected and does not run onto the following deflection roller 9 in the middle, but is pressed against a flank 9a of the deflection roller 9 - in the embodiment against the left-hand side as seen in the direction of travel of the strand 1. The position of the guide roller 8 relative to the deflection roller 9 can be precisely adjusted by a vernier 12. With the help of the vernier 12, the axis of the guide roller 8 can be moved back and forth essentially orthogonally to the center plane of the deflection roller 9.

The strand 1 wraps around the deflection roller 9 by a little less than 180 degrees. On its way from the entry point onto the deflection roller 9 on the left flank 9a to the exit point, the strand 1 moves from the flank 9a into the roller base 9b. The strand 1 moves with the strand torsion, which reduces the tendency of the strand to "curl" as described above.

The stranding machine also has a laying device 16 with the further deflection rollers 10 and 11, which can be moved along a laying axis on a spindle (not shown). The spindle is divided into two (in Fig.1 The spindle is supported by bearings 13, 14 (shown cut-away) and is driven by a drive wheel 15 (also shown cut-away). The spindle runs parallel to the spool axis of the winding spool of a winding device (also not shown).

The strand 1 runs parallel to the spindle of the laying device 16 from the deflection roller 9 and thus always runs at the same angle onto the deflection roller 10 of the laying device 16, regardless of the travel position of the laying device 16. The strand 1 is again deflected by the deflection rollers 10 and 11 in order to finally be guided to a winding device and there wound onto a winding spool (both not shown) at the axial position of the winding spool predetermined by the travel position of the laying device 16.

The driven winding spool exerts a tensile force on the strand 1, whereby the strand 1 is pressed against the deflection roller 9, preferably with a high contact force, and is thus slightly stretched between the deflection roller 9 and the winding spool, typically by 2 to 3%. In this way, the helical structure that the strand experiences through the stranding is further minimized or even completely removed. The deflection roller 9 functions as a (second) torsion lock.

List of reference symbols

1

Strand

2

Housing

3

opening

4

Trigger disc

5

Lifting roller

6, 7

Pulleys

8th

Leadership role

9

Deflection pulley

9a

first flank

9b

Roll base

10, 11

Pulleys

12

Vernier

13, 14

camp

15

drive wheel

16

Laying equipment

Claims (9)

1. Stranding machine for producing a cord (1) from a plurality of wires comprising a stranding device for stranding the wires with at least one rotatably supported deflecting roller (9) for deflecting the cord (1), characterized by at least one guiding device (8) for guiding the cord (1), wherein the guiding device (8) is arranged in such a way that the cord (1) can be guided on a straight line from the guiding device (8) to the deflecting roller (9) in such a way that the cord (1) is selectively pressed against a first flank (9a) or against a second flank which is different from the first flank (9a) of the deflecting roller (9), wherein the guiding device (8) is movable relative to the deflecting roller (9) and the flank of the deflecting roller (9) against which the cord (1) is to be pressed can be selected in this way.
2. Stranding machine according to claim 1, characterized in that the guiding device (8) is movable relative to the deflecting roller (9) substantially orthogonally to the central plane of the deflecting roller (9).
3. Stranding machine according to one of the preceding claims, characterized in that a pulling device is arranged behind the deflecting roller (9) in the direction of movement of the cord (1), which is suitable for exerting a tensile force on the cord (1) running off the deflecting roller (9).
4. Stranding machine according to claim 3, characterized in that the pulling device is a winding device.
5. Stranding machine according to one of the preceding claims, characterized in that a contact point of the cord on the guiding device (8), from which the cord (1) can be guided on a straight line to the deflecting roller (9) in such a way that the cord (1) is pressed against the first flank (9a) or against the second flank, respectively, of the deflecting roller (9), is offset with respect to the central plane of the deflecting roller (9).
6. Stranding machine according to one of the preceding claims, characterized in that the guiding device is a rotatably supported guiding roller (9).
7. Method of producing a cord (1) from a plurality of wires carried out on a stranding machine according to one of the preceding claims, wherein the guiding device (8) is moved relative to the deflecting roller (9), whereby a first flank (9a) or a second flank which is different from the first flank (9a) of the deflecting roller (9) against which the cord (1) is to be pressed is selected, the wires are stranded in the stranding device, the cord (1) is guided from the stranding device to the guiding device (8), the cord (1) is guided on a straight line from the guiding device (8) to the deflecting roller (9) in such a way that the cord (1) is pressed against the first flank (9a) or against the second flank, respectively, of the deflecting roller (9), the cord (1) is deflected by the deflecting roller (9) and the cord (1) is guided away from the deflecting roller (9).
8. Method according to claim 7, characterized in that the guiding device (8) is moved relative to the deflecting roller (9) substantially orthogonally to the central plane of the deflecting roller (9).
9. Method of producing a cord (1) according to claim 7 or 8, characterized in that the cord (1) moves from the first flank (9a) or from the second flank, respectively, into the roller base (9b) of the deflecting roller (9) during the deflection by the deflecting roller (9).

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