GRIPPER JAW AND CONDUCTOR GRIPPER FOR A PAIR OF ELECTRICAL OR OPTICAL CONDUCTORS

Abstract

A gripper jaw (G) for a conductor gripper (GA) for a pair of electrical or optical conductors (L1, L2), such as wires, cables, cable bundles or optical fibers. The conductor gripper (GA) has at least one gripper jaw (G) which is movable, by a drive assembly, relative to a second, oppositely positioned gripper jaw. The gripper jaw comprises at least one plate (1) having a gripper surface (2). The at least one plate (1) having a gripper surface (2) is mounted so as to be rotatable relative to a section that is secured against rotation (3) about an axis that is orientated perpendicularly to the gripper surface (2) and extends substantially through a middle of the gripper surface (2). The fixed section (3) is connected to the drive assembly or constructed therewith.

Claims

1-13. (canceled)

14. A gripper jaw (G) for a conductor gripper (GA) for a pair of electrical or optical conductors (L1, L2), and at least one gripper jaw (G) of the conductor gripper (GA) is movable by a drive assembly relative to a second, oppositely positioned gripper jaw, wherein the gripper jaw (G) comprises at least one plate (1) having a gripper surface (2), the plate (1) with the gripper surface (2) is rotatable relative to a section that is secured against rotation (3) about an axis that is orientated perpendicularly to the gripper surface (2) and extends substantially through a middle of said gripper surface (2), and the fixed section (3) is connected to the drive assembly or constructed therewith.

15. The gripper jaw (G) according to claim 14, wherein the plate (1) with the gripper surface (2) is passively rotatable.

16. The gripper jaw (G) according to claim 14, wherein at least one elastic element (6) is clamped between the plate (1) with the gripper surface (2) and the section that is secured against rotation (3), and the at least one elastic element (6) exerts a restoring force on the plate (1) so that the gripper surface (2) is aligned substantially transversely to the connecting line with the oppositely positioned gripper jaw (G).

17. The gripper jaw (G) according to claim 16, wherein at least one compression spring is used as an elastic element (6) between the plate (1) and the section that is secured against rotation (3).

18. The gripper jaw (G) according to claim 16, wherein the elastic element (6) is aligned substantially parallel to the connecting line with the oppositely positioned gripper jaw (G).

19. The gripper jaw (G) according to claim 16, wherein at least one further elastic element is arranged between the plate (1) with the gripper surface (2) and the section that is secured against rotation (3).

20. The gripper jaw (G) according to claim 14, wherein the rotating plate (1) with the gripper surface (2) and the section that is secured against rotation (3) form a unit that can be handled together and can be connected to the drive assembly or a fixed bearing.

21. The gripper jaw (G) according to claim 14, wherein the rotating plate (1) comprises at least two gripper surfaces (9) which are mounted in the plate (1) so as to be rotatable relative thereto, and axes of rotation of the rotating gripper surfaces (9) and an axis of rotation of the rotating plate (1) are aligned substantially parallel to one another.

22. The gripper jaw (G) according to claim 21, wherein the at least two gripper surfaces (9) are mounted so as to be passively rotatable in the plate (1).

23. A conductor gripper (GA) for a conductor processing line, for a pair of electrical or optical conductors (L1, L2), wherein the line includes at least two conductor grippers, each of which has at least one gripper jaw (G), the conductor grippers are movable relative to one another and substantially perpendicularly to positions of the conductors (L1, L2) by at least one drive assembly, and at least one of the gripper jaws (G) is designed according to claim 14.

24. The conductor gripper (GA) according to claim 23, wherein the drive assembly comprises at least one elastic element which exerts a force on at least one conductor gripper (GA) or at least one gripper jaw (G) away from the opposing conductor gripper or the opposing gripper jaw.

25. The conductor gripper (GA) according to claim 23, wherein the drive assembly comprises at least one controllable electrical, magnetic or fluid drive, which is able to cause at least movement of the conductor gripper (GA) or the gripper jaw (G) away from the opposing conductor gripper or the opposing gripper jaw.

26. The conductor gripper (GA) according to claim 25, wherein a measuring device is connected to a controller for the drive assembly at least to determine indirectly tensile tension in the conductors, and a control circuit is implemented in the controller for specifying a user-definable tensile tension.

27. The gripper jaw (G) according to claim 16, wherein the elastic element (6) comprises at least two compression springs which are each aligned substantially parallel to the connecting line with the oppositely positioned gripper jaw (G).

28. The gripper jaw (G) according to claim 16, wherein in particular at least two elastic elements are arranged symmetrically about the axis of rotation.

29. The gripper jaw (G) according to claim 14, wherein at least the rotating plate (1) with the gripper surface (2), the at least one elastic element (6), and the section that is secured against rotation (3) form a unit that can be handled together and can be connected to the drive assembly or a fixed bearing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In the drawing:

[0029] FIG. 1 is a perspective view of an embodiment of a gripper jaw according to the invention,

[0030] FIG. 2 is an exploded view of the gripper jaw of FIG. 1,

[0031] FIG. 3 is a sectional view through the gripper jaw of FIG. 1 in a plane transverse to the connecting line with the opposing gripper jaw,

[0032] FIG. 4A is a schematic representation of two conductors of different lengths clamped in gripper jaws according to the invention before the length compensation, seen from above,

[0033] FIG. 4B is a view corresponding to FIG. 4A of the conductors and gripper jaws after the length compensation by moving the gripper jaws apart,

[0034] FIG. 5 is a perspective view of a further embodiment of a gripper jaw according to the invention,

[0035] FIG. 6 is an exploded view of the gripper jaw of FIG. 5,

[0036] FIGS. 7A to 7E are diagrammatic views of the conductor ends before, during and after the length compensation and the twisting process, with a further embodiment of the invention, and

[0037] FIG. 8 shows a twisting head with a conductor gripper corresponding to an embodiment according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] FIG. 1 shows a perspective view of a gripper jaw G, as is used in conductor grippers GA that clamp the conductors L1, L2 to be twisted in twisting heads V for example (see FIG. 8) for the twisting process. Conductor grippers GA of such kind may also be provided for pulling the conductors L1, L2 in drawing in devices or for transferring conductors L1, L2 to twisting heads or the like, for example, via transfer devices. Conductors L1, L2 may be electrical or optical conductors, such as wires, cables, cable bundles or optical fibres.

[0039] For the twisting operation within the more precisely defined meaning, that is to say twisting the mutually opposite conductor ends relative to each other, at least one gripper jaw G is movable relative to a second, opposing gripper jaw by means of a drive assembly. The two gripper jaws G are advantageously of the same construction. Both gripper jaws G are fastened to a carrier frame or the twisting head V on which said gripper jaws G are mounted is fastened to a carrier frame, wherein at least one gripper jaw G and/or twisting head V is/are movable not only rotationally but also towards and/or away from the opposing gripper jaw G and/or the opposing twisting head V.

[0040] The gripper jaw G according to the invention comprises at least one plate 1 with a gripper surface 2, wherein plate 1 with gripper surface 2 is rotatable relative to a section that is secured against rotation 3, for example a base body of gripper jaw G, about an axis of rotation which is aligned perpendicularly to gripper surface 2 end extends substantially through the middle of said gripper surface 2. Plate 1 is connected rotatably to fixed section 3 via a bolt 4, so that the axis of rotation of plate 1 is determined by the central axis of bolt 4. Fixed section 3 may be fastened to twisting head V for example, at any rate fastened detachably to enable repairs or adaptations to different conductors to be made.

[0041] Rotation out of the resting position is preferably carried out passively, i.e. solely as a result of the forces that are exerted when conductors L1, L2 are placed under pretension due to the differing conductor lengths. Fixed section 3 is typically designed in such manner that it can be replaced, or connected to the drive assembly and detached again, for example via a connecting structurefor which bolts 4 may also be usedor it is integrated in said drive assembly itself. In principle, active rotation of plate 1 via actuators of any kind is also conceivable, but this then typically requires an additional sensor system as well in order to synchronize the extent of the rotation precisely with the current assembly in each case.

[0042] The exploded representation of FIG. 2 and the cross sectional view of FIG. 3 show clearly that of least one elastic element 6 is clamped between plate 1 with gripper surface 2 and the section that is secured against rotation 3. Preferably, two elastic elements 6 are arranged symmetrically on either side of the axis of rotation and of bolt 4, transversely relative to the connecting line between the mutually opposing gripper jaws G. A restoring force is exerted on plate 1 via the one or more elastic elements 6, preferably in the form of compression springs, aligning plate 1 and therewith also gripper surface 2 substantially transversely to the connecting line between the opposing gripper jaws G when no other force is acting on plate 1 or gripper surface 2. The one or more compression springs as elastic element 6 is/are preferably aligned parallel to the connecting line between the mutually opposing gripper jaws G.

[0043] FIG. 2 and FIG. 3 further show that bolt 4 is held in place in fixed section 3 via two threaded pins 7 which may be screwed into said fixed section 3, wherein said threaded pins 7 engage in boreholes on the bottom end of bolt 4, for example. The relative rotatability of plate 1 and fixed section 3 is assured via an axial ball bearing 8 for example.

[0044] Provided the fixed section 3 which is secured against rotation is not provided as part of the drive assembly for gripper jaws G, the connection between plate 1 and said fixed section by means of bolt 4 and threaded pins 7 has the additional advantage that plate 1 and section 3 are held together as a unit which can be manipulated together and connected to a fixed bearing, particularly on twisting head V or the drive assembly.

[0045] By virtue of the construction explained previously, plate 1 and therewith also gripper surface 2 may be swiveled through a few degrees of rotation from the plane aligned perpendicularly to the connecting line between the mutually opposing gripper jaws G. The resting or initial position which is parallel to this plane is determined by the restoring action of elastic elements 6.

[0046] Before the actual twisting operation during the overall twisting process, the conductors L1, L2 to be twisted are clamped at the same distance between gripper surfaces 2 on both sides of the twisting axis, which coincides with the connecting line between gripper jaws G that passes through bolt 4. Then, the specified axial tensile force is introduced into conductor pair L1, L2 before the actual twisting operation is performed. Ideally, both conductors L1, 12 are of equal length between the clamping points on both gripper jaws G (then, no swiveling movement of plates 1 with gripper surfaces 2 is necessary). Normally, however, the lengths of conductors L1 and L2 are slightly different, as is shown in FIG. 4A and emphasised by the length indicators 56 for L1 and 60 for L2. When the axial tensile force for pretensioning conductors L1 and L2 is applied by moving gripper jaws G apart via the drive assembly, plates 1based purely mechanically on the balance beam principleswivel out automatically depending on the length difference between L1 and L2 until the same tensile forces are present in both clamped conductors L1 and L2, which is represented in FIG. 4B,or until a possible swivel limit stop between plate 1 and fixed section 3 is reached.

[0047] The horizontal swiveling of plate 1 and gripper surfaces 2 with the clamped ends of conductors L1 and L2 even through very few degrees of rotation, has the effect of causing the clamped conductor end to swivel through the the same angle as well. Moreover, as the degree of twisting of conductors L1, L2 progresses, the V-shaped end region of the conductor pair is altered in such manner that the angle between the conductor ends widens continuously, wherein an additional bending load is generated on the conductor ends.

[0048] Although the advantages according to the invention are also obtained if only one of the gripper jaws G is rotatable, it is preferable if both gripper jaws G are furnished with rotatable gripper surfaces 2, as is evident from FIGS. 4A and 4B.

[0049] The further embodiment of the invention according to FIGS. 5 and 6 therefore provides that rotating plate 1 comprises of least two separate gripper surfaces 9 which can be rotated independently of each other, and which are mounted in swiveling plate 1 so as to be rotatable relative thereto and again preferably passively. For this purpose, gripper surfaces 9 are fastened to bolts 10, which are guided in axial ball bearings 11 for example and retained in plate 1 by means of threaded pins 12 that may be screwed into plate 1. The axes of rotation of the rotatable gripper surfaces 9 which are defined by the central axes of bolts 10 and the axis of rotation plate 1, which is defined by the central axis of bolt 4, are orientated substantially parallel to each other. In this way, the issue of reliably preventing buckling at the conductor ends during the twisting process is effectively addressed, as represented diagrammatically in FIG. 7A to FIG. 7E. The twisting process is carried out at relatively high rotating speeds. During the process, corresponding centrifugal forces are generated. Gripper surfaces 9 and their mountings must be designed so that only the tensile forces acting in conductors L1, L2 have an effect on the angular position of the gripper jaws, and that the centrifugal forces are neutralised.

[0050] The gripper jaw G is preferably implemented as part of a twisting head V such as is represented in FIG. 8. The entire gripper jaw G is preferably replaceable, particularly as a replacement for the gripper jaw pairs used conventionally and is arranged in the corresponding section of conductor grippers GA.

[0051] Twisting head V is typically part of a twisting device which, among other elements, is equipped with a drive motor 13 which drives twisting head V with the conductor gripper GA that comprises a plurality of assemblies via a drive belt 14 for example. The actual gripper jaws G are supported for example in linear guides in the front region of a twisting head housing 15. In order to replace the gripper jaws G, a front face end plate 16 on twisting head V is designed to be removable. The movement of the mutually facing gripper surfaces 2 of gripper jaws G for clamping and releasing the conductor ends is initiated by a preferably fixed position drive 17, possibly a pneumatic cylinder mounted on the carrier frame, via a lever 18, an axial roller bearing/thrust collar assembly 19 and a rod-lever assembly 20 which extends along the twisting head housing 15.

LIST OF REFERENCE SIGNS

[0052] 1 Rotating plate [0053] 2 Gripper surface [0054] 3 Fixed section [0055] 4 Bolt [0056] 5 Connecting structure [0057] 6 Elastic element [0058] 7 Threaded pin [0059] 8 Axial ball bearing [0060] 9 Rotating gripper surface [0061] 10 Bolt [0062] 11 Axial ball bearing [0063] 12 Threaded pin [0064] 13 Drive motor [0065] 14 Drive belt [0066] 15 Twisting head housing [0067] 16 Front face end plate [0068] 17 Drive for gripper jaws [0069] 18 Lever [0070] 19 Axial bearing/thrust collar assembly [0071] 20 Rod-lever assembly [0072] G Gripper jaw [0073] GA Conductor gripper [0074] V Twisting head [0075] L1, L2 Conductors