FR2674032A1 - Method of manufacturing a fibre-optic ribbon cable and its application to the fanning-out of the ends of fibre-optic cables - Google Patents

Abstract

The method of manufacturing a fibre-optic ribbon cable and its application to the fanning-out of the ends of fibre-optic cables enable all cable-termination cabling operations to be carried out without fusion-bonded splices or connectors. This cable protects the fibres from tension and from compression, and its shape prevents it from being twisted. It can be separated into identified single-fibre elements. It is constituted by two adhesive tapes which, when pressed against each other, trap the fibre-optic ribbon between their adhesive faces. The method of manufacture includes a simple hand-operated apparatus which permits the guiding of the fibres by combs (4) and (7) and a fibre guide (6) and of two rollers (5) which press the tapes and drive them. For the application to the fanning-out of the ends of cables, a case transmits the tensile forces from the starting cable to the ribbon cable and protects the bare-fibre parts.

Description

 The present invention relates to fiber optic cables and more particularly the wiring of their ends.

 The optical fiber cable is essentially a simple mechanical protection, a "package" for fragile optical fibers.

The weak point of the installations is located at the ends of the cable, where the multiple optical fibers flourish towards their respective connections. Generally a box is fixed on the cable which protects a connection by welding, splice or connector of each bare fiber with a monofiber cable joining the final connection.

 Our process transforms the lengths of free fiber at the end of the cable into a ribbon cable ensuring the protection of each optical fiber in tension, compression and twist. This ribbon cable is also easily separable into single fiber cables.

 It consists of a coating in two parts in the form of adhesive tapes which are applied on either side of the fibers arranged in a sheet with regular spacing.

 Each adhesive tape consists in the outer part of a support tape printing the identification of the fibers. The inner part is made of a low modulus material (foam, putty.

unvulcanized elastomer, etc. ) in which the optical fiber will drown. The entire interior face is covered with adhesive product.

 The apparatus allowing this cable to be produced can be a simple hand tool consisting of a guide of the fibers and of two rollers pressing the ribbons one against the other while trapping the fibers. One of the rollers can be operated by a crank. For the realization of great lengths of this type of cable a motorized and more sophisticated device can be realized on the same principle.

For the flourishing of a cable end a box is fixed at the end of the mechanical protection of the cable. On another face of the box are fixed the ends of the two ribbons, the box thus transmitting the tensile forces of the original cable to the ribbon cable. The non-wired part of the optical fibers is thus protected in the box. The other end of the ribbon cable can be split by cutting with scissors or following a precut of the ribbons in elements of monofiber cable each leading to a connector.

 In the case where the ribbon cable must provide good protection in compression, two false plastic fibers may be placed on either side of the fiber with a diameter slightly greater than that of the fiber.

 Figure I shows the structure of the cable (a part comprising two fibers, scale 40).

 Figure 2 shows the cable structure in the version with false fibers.

Figure 3 shows the device for making the cable "in situ"
Figure 4 shows the connection box of the ribbon cable to the original cable.

 According to a particular embodiment, the warp yarns of the ribbons may be glass yarns in order to obtain a coefficient of expansion of the ribbons close to that of the optical fiber.

 The device may consist of a base (1) supporting a vertical plate (2) on which the following elements are fixed perpendicularly - Two combs (4) and (7). The comb (7) can slide horizontally to come opposite the comb (4). Inseparable from the combs, two pressers (3) and (8) pressing on the fibers to tension them when the combs are spread.

- A fiber guide (6) in two parts which can be erected one up, another down to allow the spacing of the comb (7).

- Two pressure rollers (5) which can move apart for the same reason as the fiber guide. The upper roller includes a crank (11) for driving the ribbons, - Two axes (9) and (10) on which the ribbon wafers will be fixed. They will be fitted with brakes to adjust the tension of the ribbons.

 The use can be done as follows - Immobilization of the original cable on the plate - Placement of fibers in the order of identification between the teeth of the combs (4) and (7) close together.

- Installation of the pressers - Spacing of the combs, tightening of the fiber guide and the rollers - Action on the crank to carry out the training of the ribbon cable.

 Our method for making a fiber optic cable from two adhesive tapes and with a simple material, it will be useful to avoid at the end of the cable the multiplication of welds, splices and connections which weaken the transmitted signals, but also to realize all optical wiring of equipment, with ribbon cable or in easily identifiable separate elements.

Claims (5)

 1) The method of manufacturing a fiber optic ribbon cable is characterized by two adhesive tapes pressed one against the other by a simple device and which trap the optical fibers arranged in a ribbon between their two adhesive faces.  2) The manufacturing method according to claim 1 characterized in that the ribbons comprise an outer support layer bearing in print the identification of the fibers, precut, and in the inner layer a low modulus material.  3) The manufacturing method according to claim 1 characterized by an apparatus comprising guiding the optical fibers by comb and fiber guide, the unwinding of the ribbons and their application on the fiber web by two rollers also responsible for driving the completed cable.  4) Application of the method according to claim 1 to the flourishing of the ends of optical fiber cables characterized by a box transmitting the tensile forces from the original cable to the ribbon cable and protecting the portions of bare fibers.  5) ribbon cable produced by the method according to claim 1 which may comprise on either side of each optical fiber, a false fiber with a diameter slightly greater than that of the optical fibers.