METHOD AND DEVICE FOR STRIPPING A CABLE HAVING A MULTI-LAYERED SHEATH

Abstract

In a method for stripping a cable having a multi-layered sheath, first, an initial layer of the sheath of the cable is cut in a stripping device using at least one stripping blade. This is followed by cutting an inner layer of the sheath located opposite the first layer using a laser beam of a laser cutting device. The stripping process is completed by removal of the sheath that was cut using the stripping blade and the laser beam.

Claims

1. A method for stripping a cable having a multi-layered sheath comprising the steps of: at least partly mechanically separating at least one layer of the sheath of the cable; and at least partly separating another layer of the sheath of the cable by a thermal separation process.

2. The method for stripping a cable according to claim 1 including performing the mechanically separating step using at least one stripping blade of a stripping device and performing the thermal separation process step using a laser beam of a laser cutting device.

3. The method for stripping a cable according to claim 2 a) cutting a first layer of the sheath by performing one of the mechanically separating step and the thermal separation process step; b) cutting an inner layer of the sheath located opposite the first layer by performing another one of the mechanically separating step and the thermal separation step; and c) removing from the cable a portion of the sheath cut by the at least one stripping blade and the laser beam.

4. The method for stripping a cable according to claim 3 including repeating at least one of the mechanically separating step and the thermal separation step before performing the step c).

5. The method according to claim 3 including, after the step a) is performed, displacing a cut portion of the first layer to form a split exposing the inner layer to be cut.

6. The method according to claim 3 including between performing the steps a) and b), transferring the cable from the stripping device to the laser cutting device using a transfer device.

7. The method according to claim 6 including after the step b) is performed, returning the cable to the stripping device using the transfer device and moving the least one stripping blade of the stripping device to partly or fully remove the portion of the sheath.

8. The method according to claim 7 including forming a slit by the partly removing the portion of the sheath, and introducing into the slit the laser beam of the laser cutting device to cut an additional layer of the sheath.

9. A device for stripping a cable having a multi-layered sheath comprising: a stripping device with at least one stripping blade; and a laser cutting device wherein the stripping device and the laser cutting device are each positioned for selectively cutting different layers of the sheath.

10. The device according to claim 9 including a control device connected to the stripping device and to the laser cutting device for controlling the stripping device to cut at least one layer of the sheath and for controlling the laser cutting device to cut at least another layer of the sheath.

11. The device according to claim 9 including a transfer device for transferring the cable between the stripping device and the laser cutting device.

12. The device according to claim 11 wherein the control device automatically feeds the cable from the stripping device to the laser cutting device after the cutting of the at least one layer or feeds the cable from the laser cutting device to the stripping device after the cutting of the at least another layer.

Description

DESCRIPTION OF THE DRAWINGS

[0027] Further individual features and advantages of the invention are derived from the following descriptions of exemplary embodiments and from the drawings. Shown are:

[0028] FIG. 1 is a top view of a device according to the invention for stripping a cable having a multi-layered sheath,

[0029] FIG. 2 is an enlarged side view of a cable having a three-layered sheath with a stripped cable end,

[0030] FIG. 3 is a side view of a cable having a two-layered sheath with a first layer that has been cut by means of stripping blades and displaced to form a split,

[0031] FIG. 4 shows the cable from FIG. 3 during the cutting of a second layer by means of a laser beam,

[0032] FIG. 5 shows the cable after the laser cut of the second layer and with stripping blades retracted,

[0033] FIG. 6 shows the fully stripped cable and a two-layered sheath separated by means of stripping blades,

[0034] FIG. 7 is a side view of a cable having a three-layered sheath with the first layer cut by means of stripping blades and displaced to form a split for exposing a second layer,

[0035] FIG. 8 shows the cable according to FIG. 7 during the cutting of a second layer by means of a laser beam,

[0036] FIG. 9 shows the cable after the laser cutting of the second layer and with retracted stripping blades,

[0037] FIG. 10 shows the cable after the displacement of the second layer to form a split for exposing a third layer,

[0038] FIG. 11 shows the cable according to FIG. 10 during the cutting of the third layer by means of a laser beam,

[0039] FIG. 12 shows the cable after the laser cutting of the third player and with retracted stripping blades, and

[0040] FIG. 13 shows the fully stripped cable and a three-layered sheath separated using stripping blades.

DETAILED DESCRIPTION

[0041] FIG. 1 shows a device generally designated as 1 for stripping multi-layered cables 3. Device 1 has a feed unit 13 designed as a belt conveyor, by means of which cable 3 is brought to a swivel unit 9 along a longitudinal direction indicated as 15, which essentially corresponds to the machine longitudinal axis of device 1. Swivel unit 9 has a gripping means to hold cable 3; using the gripping means, it is possible to bring the cable in the longitudinal direction 15 to the stripping device indicated as 6.

[0042] Stripping device 6 is a known stripping device for cutting cables to length and stripping them using stripping blades (not shown here). A stripping station of this type is illustrated and described, for example, in EP 1 515 410 A2; reference is made to this document regarding details on the function and constructive design of stripping device 6. The stripping blades can be designed as V-blades, which have V-shaped cutting edges. Such V-blades are also known from EP 1 515 410 A2. The stripping blades can alternately be designed as V-blades, such as are known from EP 389 107 A1. Clearly, blades having different cutting edges and cutting geometries are also conceivable. Stripping blades having opposed cutting edges, such as those disclosed in U.S. Pat. No. 6,370,759, are tried and tested for separating layers of fabric material, in particular of glass fiber-reinforced plastics or textile fabrics. Stripping blades of this type have the advantage that the two blades are less strongly pressed apart in the cable direction.

[0043] In contrast to stripping device 6, which is arranged in the machine longitudinal axis, a second stripping station indicated with 8 is arranged next to the machine longitudinal axis. This stripping station 8 is designed as a laser cutting device. The sheath of the cable can be at least partly cut by means of a laser beam. Details of one possible embodiment of such a laser cutting device 8 can be deduced from US 2015/162729, for example.

[0044] Swivel unit 9 can be turned around a vertical axis. In the illustration according to FIG. 1, swivel unit 9 is in a tilted-out position in front of the laser cutting device 8. Swivel unit 9 thus clearly forms a transfer device by which cable 3 can be transferred from stripping device 6 to laser cutting device 8 (and, of course, also back) in a swiveling motion. By means of the two stripping stations 6 and 8, the leading cable ends of cable 3 can be stripped as described in detail in the following manner. A second swivel unit 9 and a second laser cutting unit 8 are provided for stripping the trailing cable ends of cable 3, wherein the already mentioned stripping device 6 can also be employed for the trailing cable ends.

[0045] Stripping stations 6, 8, 8 are arranged in the exemplary embodiment according to FIG. 1 on a common machine table or platform 16. Machine table or machine platform 16 can be designed as one or more pieces. Device 1 is executed in the manner of an oscillating machine, such as is already known and in use in conventional cable processing devices for assembling cables (see, for example, EP 1 447 888 A1). Device 1 for stripping multi-layered cables 3 can be designed as a linear transfer machine, for example, in which all stripping stations (6, 8, 8) are arranged along one machine longitudinal axis (15). A linear transfer machine of this type is known from EP 1 073 163 A1, for example.

[0046] In FIG. 1, device 1 has only the indicated stripping stations 6, as well as 8 and 8. It would also be conceivable to provide additional processing stations. Additional processing stations (not shown here) can be, for example, grommet stations, crimping stations and housing assembly stations.

[0047] Device 1 has a control device 17, which is connected to stripping device 6, laser cutting device 8 and swivel unit 9 as a transfer device. Control device 17 controls the respective cutting operations in stripping device 6 and laser cutting device 8. Control device 17 further controls transfer device 9 for the necessary transfer of the cable between the stripping device and the laser cutting device.

[0048] FIG. 2 shows a typical multi-layered cable 3 as is commonly used. Cable 3 encompassing one conductor 2 has a multi-layered sheath 5, which is composed of three layers here. The outer layer or layer 10 as seen from outside is an outer coating 10. This outer coating 10 can be made from PVC or another flexible plastic material and serves to insulate and protect the cable from the weather. The following, second layer, meaning the layer that lies inside, opposite first layer 10, is a fabric layer 11 or another reinforcement layer, which can be a glass cloth, for example. Finally, the third layer is formed of a thin film 12, which can consist of a plastic material. Film 12 can be designed as a screening foil. Conductor 2 here comprises a plurality of strands, which are usually made of copper or aluminum.

[0049] Individual method steps of a method according to the invention for stripping a cable 3 having a two-layered sheath 5 are illustrated in FIGS. 3 to 6. Sheath 5 of cable 3 basically corresponds to the coating structure of the cable from FIG. 2; in contrast to the cable illustrated in FIG. 2, this cable 3 lacks film (12).

[0050] The corresponding stripping method for stripping cable 3 having the two-layered sheath 5 is as follows: Cable 3 is first cut by two stripping blades 4 and 14 of a stripping device that can be moved toward each other. The respective cut depths are adjusted in such a manner that they correspond to the thickness of outer coating 10. The cutting occurs until it reaches the second layer, which is formed by fabric layer 11. The movement directions for the cutting process are each indicated with arrows e.sub.1. After cutting, stripping blades 4, 14 are displaced in longitudinal direction 15 with respect to cable 3. The displacement motion is indicated with arrows f.sub.1. The displacement can be executed by moving stripping blades 4, 14 and/or by moving cable 3 (by means of the gripping means of swivel unit 9 indicated in FIG. 1). The coating portion partly pulled off of outer coating 10 is indicated with 10.

[0051] A slit is created by means of this displacement, wherein second layer 11 is exposed by approximately the slit width s. The creation of the slit having slit width s permits the application of a laser beam for cutting second layer 11. Slit width s is dependent upon the cable to be processed and its dimensions and is typically 0.1 mm to 1 mm.

[0052] After cutting outer coating 10 and the limited displacement of this cut layer or of coating portion 10 in the stripping device, cable 3 can be brought to a laser cutting device 8 by means of a transfer device (not shown here). Control device (17) mentioned in connection with FIG. 1 is preferably designed to automatically feed cable 3 from stripping device 6 into laser cutting device 8 after the end of the cutting procedure.

[0053] The laser-cutting process is illustrated in FIG. 4. A laser beam 7 is directed against cable 3 in a radial direction by means of laser cutting device 8. By rotating the cable or by a rotation of the beam source for producing laser beam 7 around cable 3, a circumferential cut is created, by means of which fabric layer 11 is completely severed.

[0054] After cutting second layer 11 by means of the laser beam, stripping blades 4, 14 are again used. Stripping blades 4, 14 are positioned within the split between the outer coatings 10, 10 that are at a distance s apart from each other. FIG. 5 shows stripping device 6 having stripping blades 4, 14 positioned in such a manner. By the displacement of stripping blades 4, 14 in the direction f.sub.2, the fully cut sheath 10 can be pulled off of conductor 2. The fully stripped end of cable 3 is shown in FIG. 6. The separated sleeve portion of the sheath indicated with 5 is removed from the cable 3 by moving stripping blades 4, 14. Sleeve portion 5 comprises the separated coating portion 10 and the separated portion 11 of the second layer.

[0055] FIGS. 7 to 13 show a method for stripping a cable 3 having a three-layered sheath 5, which is constructed in the same way as the cable in FIG. 2. FIGS. 7 to 9 essentially correspond to FIGS. 3 to 5. Cable 3 is first partly cut by means of stripping blades 4, 14 (FIG. 7) and then partly withdrawn to about a slit width s.sub.1 (FIG. 8), then second layer 11 is cut by means of laser beam 7 (FIG. 8) and stripping blades 4, 14 are then repositioned in the slit (FIG. 9).

[0056] Stripping blades 4, 14 are now moved a small distancein contrast to the stripping process according to FIGS. 3 to 6in the direction of longitudinal direction 15 (arrows f.sub.2). In this manner, a slit is created around which the third layer 12 is exposed. FIG. 10 shows cable 3 after this displacement movement. The slit width, around which third layer 12 is exposed is indicated in FIG. 11 with s.sub.2.

[0057] The laser cutting device can now be used again. Laser beam 7 is moved in a rotational movement around cable 3 and film 12 is thus fully separated (FIG. 11). After cutting third layer 12 by means of the laser beam, stripping blades 4, 14 are positioned in such a manner that they laterally grip the shoulder of the coating 10 separated by means of the stripping blades (FIG. 12). As a result of the displacement of stripping blades 4, 14 in the f.sub.3 direction, the sheath can be completely pulled off. As shown in FIG. 13, sleeve portion 5 clearly comprises three layers, namely coating portion 10, portion 11 of the second layer, and a separated film portion that is indicated with 12.

[0058] In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.