Optical waveguides – Optical transmission cable – Loose tube type
Patent
1992-02-03
1993-06-08
Ullah, Akm E.
Optical waveguides
Optical transmission cable
Loose tube type
385113, G02B 644
Patent
active
052186598
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an optical communications cable with a tensile core and a plastic body (chambered body) that surrounds the core and has a number of closed chambers for accommodating one or more optical fibers, the outer boundary of the chambered body having grooves with locations of reduced wall thickness serving as rated break points or bead-like bulges forming the parts of the chamber outer walls.
2. Description of the Related Art
German Patent No. 25 23 735 discloses a communications cable in which a central core is surrounded by a plastic body that has a number of channels (chambers) for accommodating optical fibers. Tear strings for opening the chambers are provided in the wall bounding the chambers on their outwardly directed side.
EP-A1 0 169 647 discloses an optical cable in which the covers sealing the chambers are provided with a tear string. This tear string can have the form of a region with reduced wall thickness, and thus be peeled off. In this process, in all cases only a narrow subregion of the entire chamber cover is exposed, so that only a narrow slit is available for extracting optical fibers. Such a narrow slit does not facilitate the required ease of access nor, above all, the gripability of the optical fibers accommodated in the chamber interior.
EP-A1 0 169 647 exhibits depressions which serve as rated break points and are directed towards the bearing wall parts of the core, that is to say not towards the chamber opening. As a consequence, an unnecessarily large amount of material is removed during peeling of a part of the outer sheath situated between two rated break points. In this arrangement,two consecutive chambers have only one common rated break point. This arrangement presupposes that an outer layer (for example, a sheath) of material contrasting with the chambered body is provided.
SUMMARY OF THE INVENTION
It is the object of the invention substantially to improve the possibilities for simple opening of optical cables and thus for producing free access to the optical fibers situated in the chambers therein. According to the invention, in order to achieve this object in an optical communications cable of the type mentioned at the beginning the configuration is chosen such that the grooves or the bead-like bulges are arranged in each case on both sides of the chambers, and that the grooves or the bulges are directed towards the chambers and thus produce in each case a shell covering the chamber width.
The chambers thus closed facilitate particularly easy opening, since the rated break points or the beads that can be cut off are situated in each case on both sides of the chambers, and the entire chamber width can therefore be rendered easily accessible. In this process, no more of the material in the outer region of the cable is removed than is absolutely necessary. Moreover, the invention can be used both in the case of arrangements injection-molded in one part, and in the case of structures such as are designed with a plurality of layers, for example with an outer shell or outer sheath.
In embodying the invention, the bulges can be connected on both their sides via narrow webs to the compact chambered body. This renders it possible for such a cover to be peeled like the skin of a banana if it is desired to reach the interior of the chambers. This peeling possibility is further improved when the shell is produced from a harder or different, or else from a differently-colored material than the material of the central chambered body.
In order to prevent the simultaneously-inserted optical fibers from sticking to the hot chamber wall during the extrusion of the chambered body, the jacket of the optical fibers embedded in the chambers will be coated with a separator. As separator, use will preferably be made of a filler that is to prevent the longitudinal propagation of water in the chambers.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in detail with reference to the following description and ex
REFERENCES:
patent: 4038489 (1977-07-01), Stetson et al.
patent: 4786138 (1988-11-01), Buckley
patent: 4793686 (1988-12-01), Saito
patent: 5087110 (1992-02-01), Inagaki et al.
Siemens Aktiengesellschaft
Ullah Akm E.
LandOfFree
Optical communications cable does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical communications cable, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical communications cable will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1947977