CABLE ALIGNMENT APPARATUS AND METHOD FOR ALIGNING ASSEMBLED CABLE ENDS OF TWO CABLES OF A CABLE HARNESS IN THE CORRECT ROTATIONAL POSITION AS WELL AS ARRANGEMENT FOR ASSEMBLING PLUG HOUSINGS WITH CABLE ENDS WITH THE CABLE ALIGNMENT APPARATUS

Abstract

A dual cable alignment apparatus (10) for rotationally aligning assembled cable ends of two cables (3,4) of a twisted cable harness (2), the cable alignment apparatus (10) comprising two clamping jaws (7,8) and a central web (9) disposed between the clamping jaws (7,8). Each of the two clamping jaws (7,8), which can be moved towards one another in the closing direction (s), can clamp a cable (3,4) between the central web (9) and the clamping jaws (7,8). The clamping jaws (7,8) are further designed to be movable laterally past the central web (9) for changing the rotational position by rolling the cable (3,4) clamped between them. The clamping jaws (7,8) can be moved independently of one another in the lateral direction by means of their own lateral drives (16,17), ensuring that each cable (3,4) can be brought precisely and reliably into the desired rotational position.

Claims

1. Cable alignment apparatus (10) for aligning assembled cable ends of two cables (3, 4) of a cable harness (2), in particular a twisted cable harness, in the correct rotational position, comprising the cable alignment apparatus (10): two clamping jaws (7, 8) and a central web (9) arranged between the clamping jaws (7, 8), wherein one cable (3, 4) in each case can be clamped between the central web (9) and one of the clamping jaws (7, 8), and wherein for changing the rotational position at least one of and preferably both clamping jaws (7, 8) is or are designed to be movable laterally past the central web (9).

2. Cable alignment apparatus (10) according to claim 1, characterized in that a separate lateral drive (16, 17) is provided for at least one laterally movable clamping jaw (7, 8).

3. Cable alignment apparatus (10) according to claim 1, characterized in that the clamping jaws (7, 8) and the central web (9) each have clamping surfaces (20, 21, 22, 23) running parallel to one another, wherein the clamping surfaces (20, 21, 22, 23) are preferably profiled and wherein the clamping surfaces (20, 21, 22, 23) are particularly preferably each provided with a profiling preferably formed by grooves or slots (24, 34).

4. Cable alignment apparatus (10) according to claim 3, characterized in that the clamping jaws (7, 8) and the central web (9) are made of metallic materials which is roughened in the area of the clamping surfaces (20, 21, 22, 23) or that the clamping jaws (7, 8) and the central web (9) are coated in the area of the clamping surfaces (20, 21, 22,

23.

5. Cable alignment apparatus (10) according to claim 1, characterized in that the central web (9) comprises a tapering inlet portion (25) adjoining a clamping surface (22, 23)

6. Cable alignment apparatus (10) according to claim 1, characterized in that the central web (9) has web segments separated from one another in a step-like manner for selectively presetting different clamping surfaces (22, 23, 22′, 23′, 22″, 23″).

7. Cable alignment apparatus (10) according to claim 6, characterized in that at least one clamping segment of the central web (9) has grooves or slots (34′, 34″) which cooperate with corresponding grooves or slots (24′, 24″) of the clamping jaws (7, 8) in such a manner that, during a lateral motion, the clamping jaws (7, 8) and the central web (9) can be retracted in a partially interlocking manner.

8. Cable alignment apparatus (10) according to claim 1, characterized in that the clamping jaws (7, 8) and/or the central web (9) are equipped with sensors (26, 27) for determining the torsional moment applied to the clamped cable (3, 4).

9. Cable alignment apparatus (10) according to claim 1, characterized in that it further comprises a preferably optical detection apparatus (11) for determining the respective rotational position of the cables (3, 4).

10. Arrangement (1) for handling cables, having a cable alignment apparatus (10) for aligning assembled cable ends of two cables (3, 4) of a cable harness (2), in particular a twisted cable harness, in the correct rotational position in particular a cable alignment apparatus (10) according to claim 1 and an assembly gripping unit (12) with two individually controllable cable grippers (30, 31) for gripping and feeding to plug housings or to cells of a plug housing the assembled cable ends (14, 15) of the cables (3, 4) aligned in the rotational position.

11. Method for aligning assembled cable ends of two cables (3, 4) of a cable harness (2), in particular a twisted cable harness, in the correct rotational position, preferably using the cable alignment apparatus (10) according to claim 1, and optionally for assembling plug housings (20) with assembled cable ends of two cables (8, 9) of the cable harness, in particular a twisted cable harness, characterized in that: each of the cables (3, 4) is clamped between engagement means (7, 8, 9), and the clamped cables (3, 4) are set into a cable rolling motion by the engagement means (7, 8, 9) moving past one another, whereby the rotational position of the assembled cable ends of the cables (3, 4) is changed and thus the respective assembled cable end (14, 15) is aligned.

12. Method according to claim 11, characterized in that only one of the engagement means (7, 8) is moved per cable (3, 4) and the other engagement means (9) remains stationary.

13. Method according to claim 11, characterized in that the rotational position of the assembled cable ends is monitored by means of an optical detection apparatus (11) which uses a shadow image of the two contact elements (5, 6) of the cable ends (14, 15) for position detection, wherein, when determining the rotational position of the assembled cable ends (14, 15), the area of the shadow image at which an overlap of the shadow contours of the two contact elements (5, 6) occurs is excluded from the examination.

14. Method according to any of claim 13, characterized in that the assembled cable ends (14, 15) are pre-aligned and only thereafter the rotational position of the assembled cable ends (14, 15) is determined by means of the preferably optical detection apparatus (11).

15. Method according to claim 11, characterized in that the assembled cable ends (14, 15) assume different heights during or after the alignment procedure, and in that the ready-aligned assembled cable ends (14, 15) are respectively gripped by cable grippers (30, 31) at the different heights and brought to the desired one for assembling.

Description

DETAILED DESCRIPTION

[0061] FIG. 1 shows a cable alignment apparatus 10 for aligning the cable ends of two cables 3, 4 of a twisted cable strand 2 extending along a longitudinal axis L in the correct rotational position. Therefore, for simplicity, the term “dual cable alignment apparatus” is also used below for the cable alignment apparatus 10 handling two cables 3, 4. The respective cable is usually an electrical cable containing, for example, a solid conductor made of copper or steel or stranded wire and insulation as a sheath for the conductors.

[0062] The Cartesian coordinate system shown in FIG. 1 is used to assist in understanding the directions and major motions of the components of the dual cable alignment apparatus 10. The dual cable alignment apparatus 10 comprises two clamping jaws 7 and 8 movable transversely to the longitudinal axis L, in opposite directions between an initial or open position and a closed position in the y-direction. The longitudinal axis L also corresponds to the direction in which the respective longitudinal cable axes of the cable ends of cables 3, 4 extend. The closing motion for creating the closed position is indicated by arrows s. The dual cable alignment apparatus 10 further comprises a central web 9 arranged between the clamping jaws 7, 8. In the closed position shown in FIG. 1, the two cables 3, 4 extending approximately parallel to the axis are held in place by the cable alignment apparatus 10. One cable 3, 4 is clamped between the central web 9 and one of the clamping jaws 7, 8.

[0063] The cable alignment apparatus 10 shown here is used in particular with regard to the subsequent assembling of plug housings with assembled cable ends. In this example, crimp contacts are attached as contact elements 5, 6 to the respective stripped cable ends of the twisted cable harness 2.

[0064] As can be seen from FIG. 1, the assembled cable ends of cables 3, 4 are not aligned and are skewed with respect to the vertical and horizontal. The dual cable alignment apparatus 10 described in detail below can be used to align the cable in the correct rotational position. FIG. 2 shows a cable harness 2 with the assembled cable ends of the cables 3, 4 aligned in this manner, but with the cable ends with the contact elements 5, 6 lying on a common horizontal plane.

[0065] The twisted pair cable harness 2 shown in FIG. 2 is a so-called UTP cable. Contact elements 5, 6 with rectangular or diamond-shaped outer contours in cross-section are attached to the free ends of the cables 3, 4. However, the contact elements 5, 6 could also have other shapes that are non-circular in cross-section. Round contact elements usually do not require alignment of their rotational position. Further, grommets 35 are attached to the ends of the cables 3, 4 by way of example. Of course, grommets can also be dispensed with as required. The twisted area of the cable harness 2 is designated by 13. The short untwisted area with the assembled cable ends of cables 3, 4 adjoins this twisted area 13 at the front. Areas of the cables 3, 4 in which the clamping jaws 7, 8 and the central web 9 act on the respective cable are designated by 14, 15. However, the dual cable alignment apparatus 10 can also be used to process untwisted cable harnesses composed of two cables.

[0066] The basic structure and operation of the dual cable alignment apparatus 10 can be seen in FIGS. 3a to 3c. FIG. 3a shows the dual cable alignment apparatus 10 in an initial position. In this position, the cable ends of the cable harness can be inserted into the dual cable alignment apparatus 10. One cable 3, 4 each is then located between one of the clamping jaws 7, 8 and the centrally arranged central web 9. The two clamping jaws 7, 8 are then moved towards one another by means of feeding drives (not shown here). The corresponding closing directions or motions are indicated by arrows s1 and s2. For closing the clamping jaws 7, 8, it is advantageous to provide two feeding drives in such a manner that the feeding can be performed individually for each clamping jaw 7, 8. This also has the advantage that cables of different thicknesses can be processed if necessary. FIG. 3b shows the situation after infeed. In the closed position, the cables 3, 4 are each clamped between the central web 9 and one of the clamping jaws 7, 8.

[0067] After creating the closed position, the assembled cable ends of cables 3, 4 are usually not yet in the correct rotational position. The corresponding misalignments are indicated in FIG. 3b with angles α.sub.1 and α.sub.2. For alignment, the clamping jaws 7, 8 are now moved in lateral direction, while the central web 9 remains stationary. The corresponding lateral motion of the clamping jaws 7, 8 is indicated by arrows w.sub.1 and w.sub.2. In the case shown here, the clamping jaws 7, 8 perform a motion in opposite directions, but not coupled. However, depending on the misalignment and the desired nominal position, motions in the same direction are also conceivable. Under certain circumstances, only one of the clamping jaws 7, 8 is moved.

[0068] The clamping jaws 7, 8 and the central web 9 each have clamping surfaces 20, 21, 22, 23 extending parallel to one another. The clamping surfaces 20, 21, 22, 23 are, for example, flat. As the engagement means 7, 9; 8, 9 move past one another, the clamped cables 3, 4 are set into a cable rolling motion. In order to enable the cable rolling motion, the cables have an outer contour which is approximately circular in cross-section and is predetermined by the cable sheath, for example. The opposing clamping surfaces 20, 22; 21, 23 each provide a kind of path along which the cables can roll. The cable 3 rolls downwards when the clamping jaw 7 is moved laterally in the w.sub.1 direction. The cable 4 rolls upwards when the clamping jaw 8 is moved laterally in the w2 direction. After the lateral method, the situation shown in FIG. 3c is obtained, in which the misalignments of the assembled cable ends of cables 3, 4 are eliminated. Obviously, cables 3, 4 are now no longer at the same height. As a result of the cable rolling movements, cables 3, 4 are displaced upwards or downwards.

[0069] The lateral motion by which the respective clamping jaws 7, 8 must be moved up or down depends substantially on the angle α1, α2. These angles can be detected using detection apparatuses to determine the rotational position of the cables. Such detection apparatuses are explained in more detail below. The cable diameter is often known in advance and does not necessarily have to be recorded specifically. Based on the knowledge of the actual condition, as on the basis of the angle value α.sub.1, α.sub.2, it can be calculated, taking into account the cable diameter, to what extent the cable must be rotated and consequently how large the traversing path required for this must be.

[0070] FIGS. 4a to 4c show the dual cable alignment apparatus 10 of FIG. 1 in the same positions as in FIGS. 3a-3c. FIG. 1 and FIGS. 4a to 4c also show the respective motions for moving the individual components. Feeding drives for closing and opening the clamping jaws 7, 8 are designated as 18, 19. The feeding drive 18, which is pneumatic or electromechanical, for example, moves the clamping jaw 7 for feeding in the S.sub.1 direction, and the feeding drive 19 moves the clamping jaw 8 for feeding in the s.sub.2 direction (FIG. 4a). The two clamping jaws 7, 8 are designed to move laterally past the central web 9 by means of lateral drives 16, 17 in order to change the rotational position of the assembled cable ends of the cables 3, 4. Each clamping jaw 7, 8 is assigned its own individually controllable lateral drive 16, 17 for lateral motion. The clamping jaws 7, 8 can be moved independently of one another in the w.sub.1 and w.sub.2 directions by means of their own drives 16, 17. This ensures that each cable 3, 4 is precisely and reliably brought into the desired rotational position. The lateral drives 16, 17 are exemplarily designed as threaded rod drives with threaded rods 36. Other linear drives such as those with linear motors can also be used for the lateral drives 16, 17. Pneumatic or hydraulic lateral drives are also conceivable.

[0071] The clamping jaws 7, 8 and the central web 9 have flat clamping surfaces for applying pressure to the cables 3, 4. To increase friction, the clamping jaws 7, 8 and the central web 9 can have coatings made of an elastomer, in such a manner that advantageous clamping surfaces are created which allow the cables 3, 4 to roll without slippage. As an alternative to coating, it is also conceivable to roughen the clamping jaws 7, 8 and the central web 9 made of metallic materials in the area of their clamping surfaces, which can also increase the friction for optimum cable rolling motions.

[0072] Further design details of the dual cable alignment apparatus 10 can be seen in FIGS. 5 and 6.

[0073] To check whether the assembled cable ends of cables 3, 4 are in the correct rotational position after the alignment procedure, the optical detection apparatus 11 shown in FIG. 7 can be used. However, this optical detection apparatus 11 can also be used to determine the actual states of the cable ends, i.e. the misalignments at the beginning of the alignment procedure (cf. FIG. 3b), which are substantially characterized by the angles α1, α2. The optical detection apparatus 11 comprises an image acquisition module having a scanning unit with line sensors. The optical detection apparatus 11 further comprises a cylindrical test head 40, exemplified here, which contains the line sensors and which can be rotated around its axis in a manner known per se. For this purpose, for example, an image capture module can be used, as has already become known from EP 1 304 773 A1. For details on the structure and the basic mode of operation, please refer to this document. The present optical detection apparatus 11 differs from the known detection apparatus primarily in that it is particularly well suited for detecting assembled cable ends of two cables. This aspect will be discussed in detail below, in particular with reference to FIGS. 23 to 25.

[0074] After the angular position has been set by the lateral method of the clamping jaw 7, 8, the rotational position of the assembled cable end is checked for each cable 3, 4 using the optical detection apparatus 11 to determine whether the nominal position has actually been adopted. Otherwise, the readjustment procedure must be repeated again.

[0075] As can be seen from FIG. 7, the cable alignment apparatus 10 is equipped with linear guides 37 that ensure lateral linear motion with high precision.

[0076] After completion of the alignment procedure, in which the assembled cable ends of the two cables 3, 4 were aligned in the correct rotational position by means of the dual cable alignment apparatus 10 described above, and the alignment of the assembled cable ends in the correct rotational position is determined or checked by means of the optical detection apparatus 11, the actual assembly can be carried out as the next work step. For assembling, the assembled cable ends of the cables 3, 4 are gripped by an assembly gripping unit 12 and guided to plug housings (not shown), which is shown in FIG. 8. For example, the contact elements 5, 6 are inserted into cells of a plug housing.

[0077] The dual cable alignment apparatus 10 is thus, in the present case, a component of an arrangement for handling cables, designated 1, which will be referred to hereinafter as the “assembly arrangement” for the sake of simplicity. The assembly arrangement 1 comprises the dual cable alignment apparatus 10, the optical detection apparatus 11, and the assembly gripping unit 12.

[0078] The assembly gripping unit 12 has two cable grippers 30, 31 for gripping the assembled cable ends of cables 3, 4 and for feeding the assembled cable ends, which have been aligned in the correct rotational position, to plug housings. Each of the cable grippers 30, 31 can be controlled individually and can each be moved in the x, y and z directions. The fact that the cable grippers 30, 31 can be moved independently of one another by means of corresponding actuators ensures that the cables, which are usually at different heights after the alignment procedure, can be gripped. A third gripper 32 is also provided for strain relief of the cable harness 2 during assembling.

[0079] Further details of the assembly gripping unit 12 for the assembly arrangement 1 can be seen in FIGS. 9 and 10. In FIG. 9, for example, the directions of motion of actuators are indicated by double arrows, which can be used to move the cable grippers 30, 31. By means of actuators designated as 50, the cable grippers 30, 31 can be moved up and down in the z direction in order to be able to grip the cables 3, 4 located at different heights. Actuators 49 are used to move the cable grippers 30, 31 in the x direction; actuators 51 are used to move the cable grippers 30, 31 in the y direction. Furthermore, actuators 48 for opening and closing the cable grippers 30, 31 can be seen in FIG. 9.

[0080] The cable grippers 30, 31 grip the cables 3, 4 in each case before the components acting on the cables (clamping jaws 7, 8, central web 9). Since these components 7, 8, 9 act on a comparatively large cable portion—with respect to the longitudinal cable axis L—for the cable rolling movements, the cable grippers 30, 31 have only little space to grip the cables 3, 4. Therefore, each of the cable grippers 30, 31 has cranked front parts 33 that connect the respective gripper jaws 38 of the cable grippers to the gripper supports 39. The cranked cable grippers 30, 31 are also clearly visible in FIG. 10.

[0081] To ensure reliable rolling movement of the cable during lateral method, the two clamping jaws 7, 8 and the central web 9 can be provided with profiled clamping surfaces. Clamping surfaces with such profiles formed by grooves or slots are shown in FIGS. 11 to 16. In the embodiment example according to FIGS. 11 and 12, the grooves of the profilings extend in the z direction, i.e. at right angles to the longitudinal axis L of the cable alignment apparatus 10. The profiling is formed by grooves extending parallel to one another. The grooves of the clamping surface 20 of the clamping jaw 7 are designated as 24; the grooves of the clamping surface 22 of the central web are designated as 34. The clamping surfaces 21 and 23 associated with the other cable are configured in the same manner. Obviously, the grooves 24, 35 of the opposing clamping surfaces 20 and 22—viewed in the y direction—cover one another. This arrangement can be seen particularly well in FIG. 12. As shown in the following FIG. 16 concerning a further embodiment, the grooves can also be arranged offset from one another in the cable alignment apparatus 10.

[0082] The clamping jaws 7, 8 shown in FIG. 11 are designed as one-piece components. The components, which are preferably made of metallic materials, comprise jaws containing the clamping surfaces 20 or 21, connecting arms 28 and connecting parts 29, wherein the connecting parts 29 form spindle nuts for the previously mentioned threaded rod drives.

[0083] It can then be seen from FIGS. 11 and 12 that the central web 9 comprises a tapered inlet portion 25 which is adjacent to the clamping surfaces 22, 23 and faces the twisted area 13 of the cable harness 2. The inlet portion 25 is formed by bevels that create a favorable inlet geometry.

[0084] FIGS. 13, 14 show an alternative embodiment of the profiling. The profiles of the clamping surfaces 20, 21, 22, 23 of the two clamping jaws 7, 8 and of the central web 9 also extend transversely to the longitudinal axis L, as in the previous embodiment, but here diagonally. As FIG. 13 shows, the diagonally extending grooves 24 of the clamping jaw 7 are oriented at right angles to the grooves 34 associated with the central web 9. The same applies with regard to the clamping jaw 8. Here, too, the grooves of the clamping jaw 8 are oriented at right angles to the grooves associated with the central web.

[0085] FIGS. 15 and 16 concern another arrangement with clamping jaws 7, 8 and central web 9 for the cable alignment apparatus 10. The central web 9 has web segments separated from one another in a step-like manner for selectively presetting different clamping surfaces 22, 23; 22′, 23′; 22″, 23″. The central web 9 is shaped as a stepped column in relation to a web axis running in the z direction. The clamping surfaces 22, 23 of the first web segment, the clamping surfaces 22′, 23′ of the second web segment and the clamping surfaces 22″, 23″ of the third web segment are spaced apart by different distances as can be seen. With such an arrangement, cables of different thicknesses can be aligned in the correct rotational position. By means of a drive not shown here, the central web 9 can be retracted between the clamping jaws 7, 8. The inward and outward motion of the central web 9 would be in the direction of the z axis. In FIG. 15, the clamping jaws 7, 8 are at the level of the first web segment of the central web 9. To move to the next larger level or the level after the next, the central web 9 must be shifted by a corresponding distance in the z direction. The clamping segment of the central web 9 has grooves 34 which cooperate with corresponding grooves 24 of the clamping jaws 7, 8 in such a manner that during an alignment procedure for aligning the assembled cable ends in the correct rotational position, the clamping jaws 7, 8 and the central web 9 can be retracted in a partially interlocking manner during a lateral motion in such a manner that the next larger level does not impede the motion of the clamping jaw 7, 8.

[0086] FIGS. 17 and 18 show a clamping jaw 8 equipped with sensors for determining the torsional moment applied to the cable. Of course, the second clamping jaw is normally configured in the same manner.

[0087] Thanks to such sensors, excessive torsion of the cable in the closed position can be prevented during the lateral traversing procedure to change the rotational position and thus undesirable twisting of the cable. In the embodiment shown in FIG. 17, strain gauges arranged on an upper side and a lower side of the connecting arm 28 are arranged as sensors. A recess is provided in the connecting arm 28 to make the deformation more visible to the strain gauges in such a manner that the force can be measured precisely in the z direction. This force can be used to infer the torsion of the cable during alignment. In the alternative embodiment shown in FIG. 18, the connecting arm 28 has integrated pressure sensors 27. The two-part clamping jaw 8 consists of the connecting arm 28 with the jaw formed thereon for predefining the clamping surface 21 and of the connecting part 29. The deformation of the gripper jaw 8 in the z direction can alternatively be determined, for example, by an actual/target comparison of the clamping surfaces of the outer jaws. The position of the clamping surface in the Z direction is measured and compared with the nominal position.

[0088] It may be that the measured deformation or force only allows a limited direct conclusion on the torsion of the cable end. Clamping the cable can deform the insulation, which causes the insulation to roll when the clamping jaw is moved in the z direction. In addition to the torsional moment of the cable, the fulling resistance can therefore also act against the force of the clamping jaw (force in the z direction). Such phenomena and how they can be countered are shown in FIGS. 19a to 19d, although this is explained here using the example of cable 3 on the left in the figures.

[0089] In FIG. 19a, the jaws 7, 8 are in the closed position where the jaw 7 is in contact with the cable 3. If the clamping jaw 7 is now moved further in the direction of the arrow s, the insulation of the cable sheath of the cable 3 is deformed (FIG. 19b). When the clamping jaw 7 is moved laterally in the direction of the arrow w, the cable 3 is set into a rolling motion during which fulling takes place. As FIG. 19c shows, the cable can be brought into the correct rotational position in spite of the flexing.

[0090] Another way provides for the clamping jaw 7 to be moved briefly in the opposite direction. This counter-motion is indicated by the arrow r in FIG. 19d. Since the flexing resistance always acts in the opposite direction to the direction of motion, the fulling resistance can be eliminated by moving back briefly. The retraction of the clamping jaw serves to isolate the torsional moment of the cable from the flexing resistance. This results in a sequence according to FIGS. 19a, 19b, 19c and 19d. If a threshold value for the force in the z direction is exceeded (FIG. 19c), the reverse motion (FIG. 19d) is triggered. After retraction, the motion can be continued in the w direction (cf. FIG. 19c). There may be a very small area where only the torsional moment of the cable 3 acts. What can always be seen, however, is a clear drop in the amount of force (i.e., a drop in F) and, as the return travel continues, a curve offset by twice the amount of flexing resistance.

[0091] Resistance from walking can be quantified in two ways.

[0092] First, the offset of the force/displacement curve can be considered. Such a force/path curve is shown in FIG. 20. Since the theoretical force/path curve of the cable (dash-dotted line) passes through the zero point, the offset is largely attributable to the fulling resistance. This is substantially the same as the sequence shown in FIGS. 19a, 19b, and 19c. A force/path curve for the sequence in accordance with FIGS. 19a, 19b, 19c and 19d is shown in FIG. 21. The outward journey is represented by a solid line and the return journey by a dashed line.

[0093] The rotational position of the assembled cable ends is monitored by means of an optical detection apparatus 11, which uses a shadow image of the two contact elements 5, 6 of the cable ends 14, 15 to detect the position. FIG. 22 shows an example of a test situation with a shadow image. The optical detection apparatus 11 comprises a light curtain 11 and a line sensor 42 opposite thereto. Between them are the assembled cable ends of the two cables, wherein the contact elements 5 and 6 are shown simplified as almost rectangular cross-sectional areas. In the present embodiment, the contact elements 5 and 6 have a diamond-shaped outer contour; in other words, the cross-sections of the contact elements 5 and 6 are drawn as parallelograms. The parallelograms are obviously not perpendicular to the light curtain, which is close to a real situation where the cable ends may be slightly tilted. The optical detection apparatus 11 is rotatable around an axis of rotation extending in the direction of the x axis. The line sensor 42 captures an image after each rotation of the optical detection apparatus 11, resulting in the composite shadow image shown in FIG. 22. The axis of the shadow image, denoted by w, corresponds to the angle of rotation of the optical detection apparatus 11.

[0094] For example, the method for aligning assembled cable ends of two cables of the UTP cable in the correct rotational position may be as follows: The finished UTP cable is inserted into the cable alignment apparatus 10 and at the untwisted cable ends the cables are clamped by the clamping jaws 7, 8 in the manner described above (closed position). For strain relief, the twisted area of the cable can be kept at a certain distance from the arrangement with the clamping jaws 7, 8 and the central web 9. The optical detection apparatus 11 is then moved to a test position (see previous FIG. 7). There, the optical detection apparatus 11 rotates the test head 40 around the contact elements 5, 6 and checks the rotational position of the contact elements. The test head 40 has the light curtain 41 and the associated line sensor 42 to generate shadow images of the contact elements 5,6. As the test head 40 rotates around the contact elements 5, 6, the captured shadow images are recorded. 44 indicates the shadow edges of the contact elements illuminated in this manner.

[0095] In a manner known per se, the shadow contour is examined for local minima 45 in order to determine the rotational position of the contact elements 5, 6. However, since there are now two contact elements 5, 6, the two shadow contours 43 overlap when the test head 40 rotates around the contact elements 5, 6. In accordance with a start position, however, the shadow edges can be assigned to the contact elements 5, 6. The area of anticipated overlap is excluded from the analysis. This is the range of angles of rotation of the test head 40 in which the contact elements 5, 6 are expected to lie on top of one another (from the point of view of the line sensor). This overlap area is designated as 46 in FIG. 22.

[0096] If the contact elements 5, 6 extend approximately parallel to the axis of rotation of the test head 40 and have a rectangular cross-section in the sectional plane of the light curtain 41, then the minima 45 of a contact part 5, 6 are offset from one another by 90°. In this ideal situation, the local minima repeat after 180°. Therefore, it is not necessary to search the whole area of 360° for the minima. If the contact elements 5, 6 with rectangular cross-section extend at a small angular amount (e.g. 5°) to the axis of rotation of the test head 40, the acquired cross-section may be distorted a little to a parallelogram if the tilting axis is diagonal.

[0097] As long as the minima 45 do not move too far away from 90°, this case can be compensated by the tolerance range of the cable alignment apparatus 10.

[0098] If the cross section of the rectangular contact element is strongly distorted to a parallelogram, the current rotation position can also be calculated. The subsequent assembling process could possibly be impeded by a bent cable tip and the preceding machining process therefore has a defect. Therefore, an error message is often preferred.

[0099] If there are problems in the detection of the minima 45, the affected contact element 5, 6 can be rotated a small amount by the cable alignment apparatus and the test head 40 scans the new shadow contour. The shadow contour of the rotated contact element 5, 6 has changed shape, shifting along the angular axis of the shadow diagram. This is shown in FIGS. 23 and 24. If a minimum 45 was in the area of overlap, it would now step out of it.

[0100] To shorten the test time, it is also conceivable that the test head 40 includes a (not shown) second light curtain with associated line sensor, wherein this second light curtain would be positioned offset by 90° from the first light curtain.

[0101] The cable alignment apparatus 10 rotates the cable ends to the desired angular position after testing. At the end of the alignment procedure, the contact elements 5, 6 can be rotated differently in relation to one another, depending on the slots provided.

[0102] After completion of the alignment in the correct rotational position, the assembly gripping unit 12 comprising two individually controllable cable grippers 30, 31 grips the cable ends at their respective z positions and the optical detection apparatus is moved away from the test position. Before or during moving away, scanning of the contact elements 5, 6 is performed to determine the positions of the tips of the contact elements in a known manner. Then the cable grippers 30, 31 insert the contact elements 5, 6 into the designated slots or cells on the plug housing, adapting the assembling procedure to the positions of the tips.

[0103] In another preferred embodiment of the alignment process, the contact elements can be fed to the cable alignment apparatus 10 in a pre-aligned manner. Thanks to this measure, the angular range by which the cable alignment apparatus 10 must be able to rotate the contact elements 5, 6 can be reduced to ±20°. The examination area of the test head 40 can also be reduced, since—as shown in FIG. 25—with pre-aligned contact elements 5, 6 a local minimum 45 per contact part is sufficient to determine the rotational position. In this manner, contact elements 5, 6 with an asymmetrical cross-section can also be easily processed.