GB2186389A

GB2186389A - Optical wave guide ribbon cable production using ultrasonic welding

Info

Publication number: GB2186389A
Application number: GB08702557A
Authority: GB
Inventors: Hans Schonfeld
Original assignee: Kabelmetal Electro GmbH
Current assignee: Kabelmetal Electro GmbH
Priority date: 1986-02-06
Filing date: 1987-02-05
Publication date: 1987-08-12
Also published as: GB8702557D0; DE3603713A1; JPS62187312A

Abstract

Optical wave guides 2 are passed, together with a ribbon-shaped carrier 3, through an ultrasonic welding unit 4, and in it are welded to the carrier 3. The completed ribbon cable 6 can be wound on to a reel 7. The optical waveguides have a primary coating of plastics material. The optical waveguides and the carrier may be welded with a continuous or an intermittent weld. <IMAGE>

Description

SPECIFICATION Optical wave guide ribbon cable production This invention relates to a method for producing a ribbon cable in which a plurality of optical wave guides extend substantially parallel with one other, which method comprises attaching the optical wave guides in a predetermined mutual position to at least one common ribbon-shaped carrier (German Offenlegungsschrift 2,81 5,514).

Optical wave guides, hereinafter called simply "OWGs", are being used more and more frequently in place ofthefamiliarmetallicconductors, notably in telecommunications engineering. Like the metallic conductors, they may be combined in cables, i.e. to form "OWG cables" . Here the OWGs can be present as solid cores or as hollow cores.

They can be processed individually or combined in bundles. It is also known to combine the OWGsto provide a single unit in the form of a ribbon cable as a preliminaryto further processing.

In the ribbon cable of the German Offenlegungsschrift 2,815,514 mentioned above, the OWGs are bonded to a ribbon-shaped carrier. For this purpose, an adhesive must be applied to the carrier. However, this entails not only an additional process step but also the risk of contaminating production equipment disposed downstream ofthe adhesive applying equipment. Moreover, such an adhesive layer also has disadvantagesforthe ribbon cable itself. Thus ifthe OWGs are placed closely together, on the carrier, the adhesive layer also penetrates between the OWGs, so that they become bonded not only to the carrier but also to each other.

As a result, detaching an individual OWG for through-connection is made considerably more difficult. If, on the other hand, the OWGs are spaced well apart on the carrier, as they are in this known ribbon cable, then large areas of the adhesive layer are left free, and this rapidly leads to a troublesome contamination of the ribbon cable.

It is an object of the present invention to provide a method for producing a ribbon cable containing OWGswhichcan be carried out in a single operation and which enables one to ensure that the OWGs are connected sufficiently firmly, but easily detachably, to the carrier, and indeed onlyto the carrier.

According to the invention, there is provided a method for producing a ribbon cable in which a plurality of optical wave guides extend substantialiy parallel with one other, which method comprises attaching the requisite optical wave guides in a predetermined mutual position to at least one common ribbon-shaped carrier; wherein the optical wave guides, provided with a primary coating, are passed together with the requisite carrier in a continuous operation through an ultrasonic welding unit in which the optical wave guides are welded to the carrier.

This method is distinguished by the ease with which it can be carried out. No other aids being required, it is only necessary to pass the OWGs and the carrierjointlythrough an ultrasonic welding unit, in which the OWGs are welded to the carrier in a continuous run. Since one needs here no separate fastening elements, and particularly no adhesives, an effective device can be of very simple design, and there is no risk of contaminating parts of the production equipment. When the OWGs and carrier are welded together, there is only a slight, locally limited and short-term development of heat, so that the heat-related stresses which occur in the ribbon cable produced are at most only slight; they may even be quite inconsiderable.

Ultrasonic welding offers the further advantage that the degree of adhesion between the OWGs and the carrier can be adjusted, by changing the intensity of the sonic field. It is thus possible to make the adhesion less firm, if (for instance) OWGs and carrier are required to remain joined only during the processing. The adhesion can again be made firmer, if the compound structure is required to be retained in the completed OWG cable, so that, for example, all of the OWGs attached to carrier can be simultaneously connected to some further entity, by means of suitable connectors.

In the description which follows, the method of the invention is explained morefullywith referenceto the accompanying diagrammatic drawings, in which: Figure lisa side view of a device for carrying out a method according to the invention, Figures 2 to 4 show th ree different embodiments of ribbon cables produced by the present method, in transverse section, Figure 5shows (again in transverse section) a product comprising two ribbon cables arranged above each other, and Figure 6shows (again in transverse section) a variant comprising a product from which several ribbon cables can be cut.

In the device of Figure 1, six reels (1) are shown on to which OWGs (2) have been wound. The reels (1) can be arranged beside one other, or above one other, or in any other operable manner. The number of reels (1) depends on the number of OWGs (2) to be combined in a ribbon cable. The OWGs (2) are guided,togetherwith a ribbon-shaped carrier (3), into an ultrasonicwelding unit (4), in which the OWGs (2) are welded to the carrier (3). Forthis purpose, the carrier (3) is pulled off from a reel (5).

The ribbon cable produced (6), consisting of carrier (3) and OWGs (2), can be wound on to a reel (7).

However, it can alternatively be further processed into or in an OWG cable, given suitable production facilities. The production device is shown only diagrammatically in Figure 1, only the parts essential to an understanding ofthe method having been drawn in. Guide rollers and guiding elements, for example, have been left out, for the sake of simplicity.

The ribbon-shaped carrier (3) is composed of a synthetic resin or "plastics" material, and necessarily a material is used which allows or is compatible with ultrasonicwelding. Thus if, for mechanical reasons, a material has to be used forthe carrier (3) which is not intrinsically amenable to being ultrasonically welded, then the carrier (3) can be provided in a preliminary operation with a coating which does conferweldability. Mechanical reasons which can be relevant here include, for example, reasons relating to tensile strength and notch impact strength. In this connection, the carrier (3) can actually be itself composed of tension-resistant material.However, it is also possibletouseforthe carrier (3) a ribbon which is provided with tension-resistant elements, for example polyaramidefibre elements.

The OWGs (2) consist of an optical fibre, usually a glass fibre, provided with a primary coating. This is a coating which is prepared from a plastics material andwhich is used to provide protectionforthefibre.

The fibre is welded tp the carrier (3) through this priming coating.

As shown in Figure 2, the six OWGs (2) welded to the carrier (3) may be placed closely together.

Although the OWGs (2) are then in contact with each other, they are not actually joined to each other, but only to the carrier (3), so that, if necessary, they can be easily detached from the latter. The strength of the adhesion of the OWGs (2) to the carrier (3) can be adjusted by changing the intensity of the sonicfield of the welding unit (4). Inthis arrangement, it is also possible to carry outthe welding optionally in the nearfield or in the farfield ofthe welding unit (4). If the OWGs (2) are to adhere firmly to the carrier (3) only during the processing of the ribbon cable (6), the adhesion is adjusted so as to be not unduly strong.If, on the other hand, a common through-connection of ail six ofthe OWGs (2) is desired, the processor can arrange forthe adhesion to the carrier (3) to be stronger.

As shown in Figure 3, it is possible to weld OWGs (2) to both sides of a carrier (3). For this purpose, it is only necessaryto draw a carrier (3) with the appropriate number of OWGs (2) on the two sides of itthrough the unit (4).

If increased protection isdesiredfortheOWGs(2), they can again be sandwiched between and welded to two ribbon-shaped carriers (3) and (8) as shown in Figure 4. In this case, in fact, the two carriers (3) and (8) have the OWGs (2) in between them.

As shown in Figure 5, the OWGs (2) can also be welded to the carrier (3) at a certain separation from each other. In this case, the distance between adjacent OWGs (2) welded to one and the same carrier (3) is advantageously at least incrementally greaterthan the external diameter of the OWGs (2). It is then possible to arrange two ribbon cables (6) one above the other in such a mannerthatthe OWGs (2) of one ribbon cable are interdigitated between the OWGs (2) of the other ribbon cable. This results in improved packing density, as may be seen from Figure 5.If the number of OWGs (2) per ribbon cable in this embodiment remains the same as in Figures 2 to 4,then the ribbon cablebecomeswider; with a reduced number of OWGs (2) and correspondingly reduced width, however, one can, in almostthe same space as is ordinarily required by one ribbon cable, accommodate two ribbon cables in the case of this embodiment.

In a particularly elegant specific method of production, illustrated in Figure6, it is possible to produce two or more ribbon cables (6) in one and the same operation, assuming that carriers (3) of the appropriate width are available. After the OWGs (2) and wide carrier (3) have been welded together, the wide carrier (3) can be separated, along the lines (9) indicated in Figure 6 with dots and dashes, by cuts extending in the longitudinal direction of the ribbon, resulting in the formation of two or more ribbon cables (6).

Inasmuch as the OWGs (2) and the carrier or carriers (3) are continuously pulled through the welding unit (4), welding can also be carried out continuously, so that the OWGs (2) are welded to the carrier (3) over their entire length. However, it is also possible to carry out the welding intermittently, so that the OWGs (2) are welded to the carrier (3) only in places; the welding points then follow one behind another in the axial direction of the OWGs (2). Such a construction can be of particular interest if increased flexibility is demanded of the ribbon cable (6).

If desired, the carrier (3) can have a structure which is not capable of transmitting longitudinal forces of any significant magnitude. Such a structure ofthe carrier can be achieved, for example, by the incorporation in it of fibres which extend in its transverse direction. There is then no possibility that any thermal loads which may affect the ribbon cable (6) will produce axial stressing of on the OWGs (2).

It will be understood that the invention has been described above purely byway of example, and that various modifications of detail can be made within the ambit of the invention.

Claims

1. Method for producing a ribbon cable in which a plurality of optical wave guides extend substantially parallel with one other, which method comprises attaching the requisite optical wave guides in a predetermined mutual position to at least one common ribbon-shaped carrier; wherein the optical wave guides, provided with a primary coating, are passed together with the requisite carrier in a continuous operation through an ultrasonic welding unit in which the optical wave guides are welded to the carrier.

2. Method according to claim 1, wherein the optical wave guides and carrier are welded together with a continuous weld.

3. Method according to claim 1, wherein the optical wave guides and carrier are intermittently welded together, with welding points which follow one behind another in the axial direction of the optical wave guides.

4. Method according to claim 1, 2 or 3, wherein the optical wave guides are ultrasonically welded to both of the opposite faces of the ribbon-shaped carrier.

5. Method according to any of claims 1 to 4, wherein the optical wave guides are welded to the carrier at a predetermined separation from each other, the distance between optical wave guides welded to the carrier being at least incrementally greaterthan the external diameter ofthe optical wave guides.

6. Method according to any of claims 1 to 3, wherein the optical wave guides are disposed between two ribbon-shaped carriers, and are ultrasonically welded to both of these carriers.

7. Method according to any of claims 1 to 6, wherein the carrier used comprises a plastics ribbon.

8. Method according to any of claims 1 to 7, wherein an intrinsicallytension-resistant plastics ribbon is used as the carrier.

9. Method according to any of claims 1 to 7, wherein a plastics ribbon provided with tension-resistant elements is used as the carrier.

10. Method according to anyof claims 1 to9, wherein a plastics ribbon provided with a layer of an ultrasonically weldable material is used as the carrier.

11. Method according to claim 1 ,substantially as described with reference to any Figure or Figures of the accompanying drawing.

12. An optical wave guide ribbon cable produced buy a method according to any of claims 1 toll.