Method and apparatus for stranding individual cables

Abstract

The invention relates to a method and a device (400) for stranding single cables (11, 12) about a stranding axis (V). The single cables (11, 12) extend along cable axes (v1, v2) and have wires (11a, 12a) stranded in a strand stranding direction (S, Z) to form strands, each single cable (11, 12) further having a first cable end (15, 16) and a second cable end (17, 18). In each case, the first cable end (15, 16) is held by a single wire rotating unit (41, 42), respectively. The second cable end (17, 18) is held by a stranding unit (30). The second cable ends (17, 18) are jointly rotated about the stranding axis (V) counter to the strand stranding direction (S, Z) to form a stranded cable bundle (10). During the joint rotation, the first cable ends (15, 16) are individually rotated about the cable axes (v1, v2) of the respective single cable (11, 12) in the same direction of rotation as the joint rotation. Thereby, the torsion of each single cable is eased.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for stranding single cables, particularly for stranding single cables into pairs to form cable bundles. Background Technology

[0002] Cable bundles, composed of individual cables twisted together (hereinafter referred to as cable bundle stranding), are required in various industrial applications. Each individual cable has strands, which are formed by stranded wire (hereinafter referred to as strand stranding). Insulation layers surround the individual strands of each cable. Before the cable bundle is stranded, the individual cables are cut to a certain length, i.e., trimmed, and optionally, they can be assembled, i.e., contact components are installed.

[0003] EP1032095A2 discloses a stranding device for simultaneously processing three conductor pairs. A pair of conductors, i.e., a pair of single cables, is held between a holding unit and a stranding head. The stranding head rotates about a stranding axis, thereby performing the stranding process. The resulting shortening of the conductor pairs is compensated by the movement of the stranding head parallel to the stranding axis. The stranding device disclosed in EP1032095A2 is used for assembling and stranding cables (hereinafter referred to as automated production). In known variations, the stranding device is used only for stranding and not for assembling cables (hereinafter referred to as semi-automatic production). In the case of the variant device, the shortening associated with the stranding of the conductor pairs is compensated, for example, by the movement of the holding unit parallel to the stranding axis.

[0004] WO2013 / 068990A1 discloses a twisting device similar to the twisting device disclosed in EP1032095A2, wherein it is provided with two twisting heads that rotate in opposite directions.

[0005] WO98 / 06155A1 discloses a stranding device similar to the stranding device disclosed in EP1032095A2, wherein, in each case, a detwisting unit is provided for each cable end, thereby replacing the holding unit, the detwisting unit rotating in the same direction of rotation as the stranding head during the stranding process.

[0006] Technical problems that need to be solved

[0007] The specific properties of a cable bundle obtained by stranding include, for example, the required lay pitch or stranding pitch, and the required number of twists or stranding twists. Lay pitch is generally understood as the distance or average distance between two adjacent, identical intersections of a single cable when projected onto a plane. Therefore, the number of twists is equal to the sum of these intersections.

[0008] Cable bundles obtained by stranding always possess a certain degree of elasticity around the stranding axis. In the case of cables obtained by stranding according to EP1032095A2 or WO2013 / 068990A1, the cable bundle (here: cable pair) tends to untwist again in the opposite direction to the stranded state after the stranding process ends, thus at least partially untwisting again. Therefore, the number of twists and / or the lay length may vary unacceptably or may deviate from the specified values. It is well known that this phenomenon is counteracted by ensuring that the stranding process lasts longer than the duration required for the desired lay length and / or number of twists (“over-stretching”). A subsequent rotational movement in the opposite direction (“reverse stranding”) can then reduce or decrease the elastic deformation of the cable bundle, respectively. High torsional forces may be generated due to over-stretching, which may be unnecessary or unacceptable, especially for cables with small strand cross-sections.

[0009] WO98 / 06155A1 attempts to avoid excessive torsional forces by using a detwisting unit for torsional compensation during the stranding process. Since the cable ends are no longer rotatably fixed in the detwisting unit relative to the stranding head, a guide unit in the form of a drill shuttle is provided to specify the lay pitch. This guide device separates the two cables by pins and moves from the stranding head to the detwisting unit during stranding.

[0010] However, for cable bundles obtained according to WO98 / 06155A1, the lay pitch is dispersed in an unacceptable manner; that is, the lay pitch deviation between two identical cable bundles and the lay pitch deviation within the same cable bundle may be unacceptably high. For cable bundles obtained according to the technique of WO98 / 06155A1, the distance between intersections is sometimes large, which also forms between individual cables (so-called large openings), reducing the quality of the obtained cable bundle.

[0011] In view of the above problems, the object of the present invention is to provide an improved option for stranding single cables to form cable bundles. Summary of the Invention

[0012] According to one aspect, the present invention provides a method for stranding a single cable around a stranding axis. Each single cable extends along a cable axis. Each single cable has multiple wires that are stranded in a stranding direction to form strands. Each single cable also has a first cable end and a second cable end. The method includes holding the first cable end and holding the second cable end respectively, and then rotating the second cable end together about the stranding axis in a direction opposite to the stranding direction to form a stranded cable bundle including a specified or specifyable number of twists and / or a specified or specifyable strand pitch. During the common rotation, each first cable end rotates about the cable axis of its respective single cable, i.e., in the same direction of rotation as the common rotation, to release tension in each single cable.

[0013] According to another aspect, an apparatus is provided configured to perform the method described herein. The apparatus has a single-wire or separate rotating unit and a stranding unit. The single-wire rotating unit is configured to hold a corresponding one of the first cable ends. The stranding unit is configured to hold a second cable end. The single-wire rotating unit and the stranding unit are arranged such that they hold a single cable substantially parallel to the stranding axis. Attached Figure Description

[0014] Further details regarding the implementation methods, including their features, advantages, and effects, can be gleaned from the following description in conjunction with the accompanying drawings.

[0015] in:

[0016] Figure 1 A schematic diagram of the cable bundle area is shown to explain the terminology used herein;

[0017] Figure 2 A schematic diagram of a stranding device including a stranding unit and a holding unit is shown;

[0018] Figure 3 A schematic diagram of a twisting device is shown, comprising two twisting units arranged opposite each other.

[0019] Figure 4 A schematic diagram of a stranding device is shown, including stranding units and corresponding single-wire rotating units for each individual cable.

[0020] Figure 5 A schematic diagram of a cable bundle including a single cable is shown to explain the strand twisting direction and the cable twisting direction;

[0021] Figure 6 A figure is shown illustrating the manufacturable area of ​​the cable bundle for "co-directional twisting" in the alternative embodiment; and

[0022] Figure 7 A figure is shown, illustrating the manufacturable area of ​​a cable bundle used for "anti-twist stranding" in an alternative implementation. Detailed Implementation

[0023] Figure 1 A schematic diagram of a region of a cable bundle is shown, the region being generally indicated by 10. The cable bundle consists of single cables 11 and 12 as cable pairs. It should be noted that the number of two single cables 11, 12 is exemplary and non-limiting, and the aspects and features described herein can be applied in whole or in part to cable bundles having more than two single cables 11, 12, producing the same or similar effects. In an embodiment, two single cables 11, 12 can still be used in a single cable bundle 10.

[0024] exist Figure 1 In this embodiment, the first cable end 15 of the single cable 11 and the first cable end 16 of the single cable 12 are located on the same side. For example, the first cable ends 15 and 16 have already been assembled. In this embodiment, the first cable end has a contact 13a and a swivel 13b, and the second cable end 16 has a contact 14a and a swivel 14b. Each single cable has strands formed of stranded wire, which will be referred to below. Figure 5 To explain in more detail. Figure 1 In the area to the right of the dashed line marked B, single cables 11 and 12 are twisted together; therefore, in the projection plane, for example, in... Figure 1 In the drawing plane, there are points where single cables 11 and 12 intersect. When there are single cables of the same order at two intersection points in a direction perpendicular to the projection plane, there are identical intersection points in the projection plane. The distance between two adjacent identical intersection points is called the twist pitch, or simply the twist pitch, denoted by 'a'. Two eyelets 19 are formed in the projection plane between two adjacent identical intersection points, and for high-quality cable bundles 10, they should be as small as possible.

[0025] Also used in the following paragraphs Figure 1 The terminology used in this context will not be repeated here.

[0026] Figure 2A schematic diagram of a conventional stranding device 200 is shown, comprising a cable bundle 10 holding two single cables 11, 12. The second end 17 of the single cable 11 is located opposite the first end 15 of the single cable 11. Therefore, the second end 18 of the single cable 12 is located opposite the first end 16 of the single cable 12. The second end 17 and the second end 18 are jointly clamped into a stranding unit 30. The first end 15 is clamped into a first holding unit 21. The first end 16 is clamped into a second holding unit 22. The stranding unit 30 is configured to rotate about a stranding axis V to perform a stranding process in the stranding direction P. To compensate for the shortening of the single cables 11, 12 twisted together during the stranding process, the stranding unit 30 is capable of moving substantially parallel to the stranding axis V in the direction u. As used herein, the direction extending parallel to the stranding axis V also includes the direction of the stranding axis V itself.

[0027] Figure 3 It shows according to Figure 2 The twisting device 200 and the twisting device 300 are described above. Unlike the twisting device 200, the holding units 21 and 22 are not present in the twisting device 300. Instead, another twisting unit 31 is provided. The front ends 15 and 16 are jointly held in the other twisting unit 31. The twisting unit 30 is configured such that it can rotate about the twisting axis V while performing the twisting process in the twisting direction P, while the other twisting unit 31 is configured such that it can rotate about the twisting axis while performing the twisting process in the opposite direction Q.

[0028] for Figure 2 and Figure 3 The stranding devices 200 and 300 shown form a substantially uniform lay length 'a' over a sufficiently large area of ​​the cable bundle, resulting in adequate mechanical prestress in the individual cables 11 and 12. The lay length depends largely on the material properties of the individual cables 11 and 12 and the number of rotations of the stranding unit 30 and optionally another stranding unit 31 during the stranding process. Especially with smaller strand cross-sections, torsion of the individual cables 11 and 12, i.e., high mechanical prestress in the individual cables, is undesirable.

[0029] Figure 4 It shows something similar to Figure 2 and Figure 3 The stranding device 400 can be used to perform the methods disclosed herein according to embodiments. The stranding device 400 and... Figure 1The stranding device 100 differs in that, for example, a single-wire rotating unit (a separate rotating unit) 41 is provided for clamping a first end 15 of a single cable 11, and a single-wire rotating unit 42 is provided for clamping a second end 16 of a single cable 12. The single-wire rotating unit 41 is configured such that it holds the first end 15 of the clamped single cable 11 along its cable axis v1 on the first end 15. The single-wire rotating unit 42 is configured such that it holds the first end 16 of the clamped single cable 12 along its cable axis v2 on the first end 16. The two single-wire rotating units 41, 42 are also configured such that they hold the single cables 11, 12 substantially parallel to the stranding axis V at their respective first ends 15, 16.

[0030] exist Figure 4 In this winding device 400, a guide device 35 is also included for at least partially separating the individual cables 11, 12. The guide device 35 can move substantially parallel to the winding axis V in the x-direction. Through the guided or controlled movement of the guide device 35 during winding, the lay pitch a can be kept constant or varied as needed.

[0031] According to Figure 2 and Figure 3 The situation is similar for the twisting devices 200 and 300. Figure 4 The stranding device 400, whose stranding unit 30 can also rotate at least along the stranding direction P about the stranding axis V, that is, it can be driven in a rotational manner about the stranding axis. The single-wire rotating unit 41 can optionally rotate back and forth about the cable axis v1. This is achieved through... Figure 4 The double arrow Q1 in the diagram represents this. Therefore, the single-wire rotating unit 42 can optionally rotate back and forth about the cable axis v2. This is due to... Figure 4 The double arrow Q2 in the diagram represents...

[0032] The method disclosed herein specifies that, for example, the first cable ends 15, 16 are via... Figure 4 The individual single-wire rotating units 41, 42 of the device 400 are held separately. This holding represents, for example, the state before the stranding process begins, when the individual cables 11, 12 are clamped into the device 400, i.e., the stranding process is performed after holding.

[0033] During the stranding process, the second cable ends 17 and 18 rotate together around the stranding axis V, thereby forming a stranded cable bundle 10 with a specified or predeterminable number of twists and / or a specified or predeterminable twist length a.

[0034] Compared to methods known in the prior art, this common rotation about the strand axis V occurs in the opposite direction to the strand twisting direction, as will be explained below. Figure 5 Further description.

[0035] Again, compared to methods known in the prior art, each of the first cable ends 15, 16 rotates about its respective cable axis v1, v2 during the common rotation, that is, rotates in the same direction of rotation as the common rotation. This is achieved, for example, by driving the corresponding single-wire rotating devices 41, 42 in the appropriate direction of rotation Q1 or Q2 respectively. As a result, the corresponding single cables 11, 12 are de-twisted.

[0036] As used herein, the release of torsion includes, for example, reducing or eliminating the torsional force or torque generated by the common rotation in each individual cable 11, 12. To achieve the advantages described herein, the release or de-torsion need not occur completely. This means that, during stranding, the (total) rotation angle of the torsion unit 30 can be less than the (total) rotation angle of the single-wire rotation units 41, 42.

[0037] In the case described herein, reverse twisting occurs. Reverse twisting thus indicates the reversibility between the (rotating) cable stranding direction and the (rotating) strand stranding direction.

[0038] Figure 5 The diagram schematically illustrates, for example, a cable bundle 10 of two single cables 11, 12 and the corresponding strands in two alternative schemes: in alternative scheme A ( Figure 5 (Left side), viewed from the cable end, the strand twisting direction is clockwise (strand twisting direction S). Therefore, in Alternative Option A, the stranded wires 11a and 12a that form the strands extend from the upper left to the lower right in the projection plane shown. Therefore, in Alternative Option A, the individual cables 11 and 12 that form the stranded cable bundle 10 extend from the lower left to the upper right in the projection plane shown (cable twisting direction Z). In Alternative Option B ( Figure 5 (On the right side), viewed from the cable end, the strand twisting direction is counterclockwise (strand twisting direction Z). Therefore, in Alternative Scheme A, the stranded wires 11a and 12a that form the strands extend from the lower left to the upper right in the projection plane shown. Therefore, in Alternative Scheme A, the individual cables 11 and 12 that form the stranded cable bundle 10 extend from the upper left to the lower right in the projection plane shown (cable twisting direction S).

[0039] It has been shown that the method described herein can yield stranded cable bundles 10 with very low differences or deviations in lay pitch and number of twists, and with very small apertures. Furthermore, according to the method of the present invention, each individual cable 11, 12 is only slightly twisted. The resulting cable bundle 10 has no tendency to untwist or only a minimal tendency to untwist.

[0040] Figure 6A diagram is shown in which a qualitative comparison is made between the strand pitch a (cable pitch) and the wire strand pitch b, that is, during stranding in the same direction (equal pitch), according to the prior art. Figure 7 A figure is also shown, in which a qualitative comparison is made between the strand pitch 'a' (cable travel length) and the strand pitch, i.e., during reverse twisting (anti-twist) stranding as described herein. In each case, the area where the cable bundle exhibits good quality characteristics is indicated by reference numeral 50. The area where the cable bundle no longer has optimal quality characteristics under various conditions is indicated by reference numeral 60. The area where cable bundles can no longer be produced under various conditions is indicated by reference numeral 70. It has been shown that the reverse twisting method according to the method described herein achieves significant process improvements.

[0041] Other alternatives and implementations will now be described in conjunction with the accompanying drawings, which have been described in more detail above.

[0042] According to one embodiment, the method further includes: each of the first cable ends 15, 16 is individually rotated about the cable axis v1, v2 of the corresponding individual cable before common rotation to perform pre-twist. As used herein, pre-twist involves systematically applying torsion to the corresponding individual cable before the stranding process. The pre-twist is performed in such a manner that torsion-related damage to the corresponding individual cable is avoided. The pre-twist has similar effects to over-stretching and subsequent reverse stranding described above with reference to the prior art. However, it has been shown that the strain of the strands is smaller. It has also been shown that, with the method of pre-twist extension, the individual cables 11, 12 are closer together in the pre-stretched cable bundle 10, and the eyelet size is reduced without increasing the prestress. The stranded cable bundle 10 also maintains higher dimensional stability. The tendency for automatic untwisting of the unstretched cable ends 15, 16; 17, 18 is further reduced.

[0043] In an alternative embodiment, the individual rotation for pre-twisting is performed in each case along the strand stranding directions S and Z. In this alternative embodiment, the helical geometry of the stranded cable bundle 10 can be compensated in the respective individual cable x, thereby reducing or even completely eliminating the twist in the stranded cable bundle 10.

[0044] In another alternative embodiment, the individual rotation for pre-twisting is performed in each case in the opposite direction to the strand stranding directions S and Z. In this alternative embodiment, the formation of large holes can be further reduced. Furthermore, in this alternative embodiment, the tendency for automatic untwisting of the unstretched cable ends 15, 16; 17, 18 is further reduced.

[0045] According to one embodiment, the individual rotation of each of the first cable ends 15, 16 for pre-twisting is performed about a rotation angle, which is at most 10% of the total rotation angle, and this total rotation angle is necessary for the second cable ends 17, 18 to reach the number of twists. It has been proven that this pre-twisting of at most 10% of the number of twists is sufficient to achieve the effects and advantages described herein.

[0046] According to one embodiment, the method further includes repeatedly determining a variable related to the torque or torsional stress of at least one of the individual cables. The first cable end is rotated individually about the cable axis of the respective individual cable until the determined variable falls below a preset or presettable threshold.

[0047] According to one embodiment, the method further includes trimming a single cable. In alternative or other embodiments, the method further includes attaching one or more contact components 13a, 13b, 14a, 14b to at least one of the first cable ends 15, 16 and the second cable ends 17, 18.

[0048] According to one embodiment, the method further includes moving the first and second cable ends toward each other. This can compensate for stranding-related shortening of the cable bundle. For example, for this purpose, the stranding unit 30 is movably arranged parallel to the stranding axis V. In alternative or other embodiments, for this purpose, all the single-wire rotating units 41, 42 are movably arranged parallel to the stranding axis V. For this purpose, the device 400 is configured, for example, to move the first and second cable ends 11, 12 toward each other by the movably arranged stranding unit 30 and / or single-wire rotating units 41, 42 to compensate for stranding-related shortening of the cable bundle.

[0049] According to one embodiment associated with device 400, the stranding unit 30 is movably arranged parallel to the stranding axis V. In alternative or other embodiments, all single-wire rotating units 41, 42 are movably arranged parallel to the stranding axis V. Device 400 is configured to apply a tension substantially parallel to the stranding axis V to extend individual cables 11, 12 and / or cable bundles 10. This extension can be performed before and / or during stranding. This can further improve the uniformity of the stranded cable bundles 10, especially the uniformity of the lay length a.

[0050] According to one embodiment related to device 400, device 400 includes a guide device 35 for at least partially separating individual cables 11, 12. The guide device 35 is movable in the x-direction substantially parallel to the stranding axis V. Device 400 is configured such that the guide device 35 moves substantially synchronously in the x-direction with the rotation-related variables of the stranding unit 30 at the first cable ends 15, 16. This can further improve the uniformity of the stranded cable bundle 10, especially the uniformity of the lay length a.

[0051] It should be noted that the aspects, features, and implementations described herein can be combined as needed in the context of the actions of those skilled in the art, and / or individual features can be varied or omitted. The described implementations are exemplary, and their features can be modified or adjusted, and combined and / or omitted as appropriate, without departing from the scope of the invention as defined by the claims.

Claims

1. A method for stranding a single cable around a stranding axis, wherein, The individual cables extend along the cable axis and include wires, which are twisted together to form strands in the stranding direction. Each individual cable includes a first cable end and a second cable end. The method sequentially includes the following processes: Keep the first cable end and the second cable end respectively; The second cable end rotates around the stranding axis in a direction opposite to the strand stranding direction to form a stranded cable bundle including a specified number of twists and / or a specified strand pitch; and During the common rotation: the first cable end rotates individually about the cable axis of the corresponding single cable in the same rotation direction as the common rotation, so as to alleviate the tension of the corresponding single cable; The method further includes: Prior to the common rotation, the first cable end is rotated individually about the cable axis of the respective single cable for pre-twisting.

2. The method according to claim 1, characterized in that: In each case, the individual rotation for the pre-twist is performed in the strand strand twisting direction.

3. The method according to claim 1, characterized in that: In each case, the individual rotation for the pre-twist is performed in the opposite direction to the strand twisting direction.

4. The method according to any one of claims 1-3, characterized in that: Each first cable end for the pre-twisting is individually rotated about a rotation angle, which is at most 10% of the total rotation angle, the total rotation angle being necessary for the second cable end to achieve the stated number of twists.

5. The method according to any one of claims 1-3, characterized in that: Also includes: Repeatedly determine the variables related to the torque or torsional stress of at least one of the individual cables; Specifically, the first cable end is rotated individually around the cable axis of the corresponding single cable until the determined variable is reduced to below a preset or presettable threshold.

6. The method according to any one of claims 1-3, characterized in that: The cable bundle comprises two single cables.

7. The method according to any one of claims 1-3, characterized in that: Also includes: Repairing a single cable; and / or One or more contact components are attached to at least one of the first cable end and the second cable end of the single cable.

8. The method according to any one of claims 1-3, characterized in that: Also includes: Prior to the common rotation, a tension force is applied substantially along the stranding axis to extend the individual cable and / or the cable bundle.

9. The method according to claim 1, characterized in that: Also includes: The first cable end and the second cable end are moved toward each other to compensate for the shortening of the cable bundle related to twisting.

10. A device for stranding a single cable around a stranding axis, wherein, The individual cables extend along the cable axis and include wires, which are stranded to form strands in the stranding direction. Each individual cable includes a first cable end and a second cable end. The device includes: A single-wire rotating unit is used to hold one of the respective ends of the first cable. A stranding unit, used to hold the second cable end; The single-wire rotating unit and the stranding unit are configured such that they keep the single cable substantially parallel to the stranding axis. The device is configured to perform: Keep the first cable end and the second cable end respectively; The second cable end rotates around the stranding axis in a direction opposite to the stranding direction to form a stranded cable bundle including a specified number of twists and / or a specified stranding pitch; Prior to the common rotation, the first cable end is rotated individually about the cable axis of the respective individual cable for pre-twisting; and During the common rotation: the first cable end rotates independently about the cable axis of the corresponding single cable in the same rotational direction as the common rotation, so as to alleviate the tension of the corresponding single cable.

11. The apparatus according to claim 10, characterized in that: The twisting unit can be driven to rotate around the twisting axis.

12. The apparatus according to claim 10 or 11, characterized in that: The stranding unit or all the single-wire rotating units, or the stranding unit and all the single-wire rotating units are also movably arranged substantially parallel to the stranding axis, and the device is configured such that it moves the first cable end and the second cable end toward each other to compensate for the stranding-related shortening of the cable bundle.

13. The apparatus according to claim 10 or 11, characterized in that: The stranding unit or all the single-wire rotating units, or the stranding unit and all the single-wire rotating units are also movably arranged substantially along the stranding axis, and the device is configured to apply a tension substantially parallel to the stranding axis before the common rotation to extend the single cable and / or cable bundle.

14. The apparatus according to claim 10 or 11, characterized in that: It also includes a guide device disposed between the single-wire rotating unit and the stranding unit, wherein the guide device is configured to separate the single cable at least in certain areas.

15. The apparatus according to claim 14, characterized in that: The device is configured such that the guide device moves substantially synchronously with the rotational variables of the stranding unit in the direction of the first cable end.

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