FR2670586A1 - Connection box for fibre-optic cables - Google Patents

Abstract

The present invention relates to the connection and/or the distribution of fibre-optic cables. The invention essentially consists in providing cassettes (4) receiving the splices, for example, of the same elementary cable, (module), the said cassettes then being stored in the grooves of a rack (1), the said rack (1) being carried by a frame (2, 3, 6) and possibly covered by a cap (cover) (7). Application to the modular design of the wiring and to a low-cost manufacture.

Description

 The present invention relates to the connection and / or distribution of optical fiber cables and more particularly to the production of such boxes according to a modular concept, compatible with a wide range of capacity and therefore of applications.

 The present invention applies in particular to the splicing of optical fibers or to their multiplexing, or even to the connection of optical fibers from a cable to couplers.

 Connection boxes or frames have already been described. Thus, the chassis described in French patent 2,633,061 of the Applicant allow the fiber to fiber connection, the coupling, the mixing in a very general way of optical fiber cables.

 But these junction boxes are extremely expensive, bulky and not conducive to wide applications.

 The invention proposes to overcome the drawbacks of connection boxes and in particular splicing of the prior art.

 The invention also consists in facilitating handling, both during installation and in the event of repairs.

 The invention essentially consists in providing cassettes cooperating with a chassis, said chassis being carried by a frame and possibly being covered by a cover, each cassette receiving a splice for example of the same elementary cable (module).

 The protective and storage cassette of the invention is essentially formed by two plates (41, 42) at least separated by a hinge 43, said plate 41 serving as a cover, the other plate 42 serving as the bottom, said hinge 43 allowing the opening of said cassette.

 According to a characteristic of the invention, the cassette comprises, near its center, a boss 48, said boss 48 being intended to receive said connection device (connectors, splices, couplers).

 According to another characteristic of the invention, the cassette comprises, near its center, also a core 49 intended to receive and protect the excess lengths of optical fibers joined by said connection device carried by said ribbon 48.

 According to another characteristic, on either side of the core 49, are placed jumpers I for hanging excess towers of optical fiber.

 Each tray (41, 42) of the cassette is further terminated by a tongue 44a (resp 44b), said tabs fitting together so as to close the bottom 42 and the cover 41 of the cassette.

 According to another characteristic, the cassette 4 is obtained by thermoforming of a plastic material, for example PVC.

 According to another characteristic, the cassette 4 of the invention is designed to fit into the grooves 133 of a chassis 1 grooved on two opposite faces, the grooves 133 cooperating in pairs and receiving the tongues (44a, 44b) and the hinge 43 in order to allow the cassette 4 to be held in the chassis and to be extracted by sliding in the grooves 13.

 The chassis 1 is a substantially rectangular box open along a plane perpendicular to said grooves 133 in order to allow the cassettes 4 to slide and be extracted.

 The chassis 1 has a number i of grooves 133, as a function of the number of cassettes and therefore of elementary cables mj to be connected and / or distributed.

 According to another characteristic, the chassis 1 is a substantially rectangular box open along a plane perpendicular to said grooves.

 In addition, the frame 1 is advantageously obtained by thermoforming of a plastic material such as PVC or the like.

 According to another characteristic, the chassis 1 is surmounted by a template 14 which is substantially curved towards the rear in order to apply to the modules (mi, mj) of incoming or outgoing optical fibers (m'i, m'j) a radius of suitable curvature, this template 14 comprising means for guiding said incoming and / or outgoing modules, grouping means, location means.

 In addition, the incoming and outgoing modules (mi, mj) and outgoing (m'i, m'j) are advantageously arranged in two grooves (re, rs) respectively, produced externally to said chassis 1 on the side opposite to the opening, said modules being introduced therein by elastic deformation of said chassis 1.

 Other advantages and characteristics will appear on reading the following description illustrated by drawings.

 Figure 1 shows a sectional view of a connection box for optical cables, according to the invention, for example fixed against a wall.

Figure 2 shows a front view in partial section along
DD 'of the connection box of figure 1.

 Figure 3 shows a top view of a cassette 4 according to the invention cooperating with the connection box.

 FIG. 4 represents a front view of the open cassette of FIG. 1 during a distribution operation of the optical fiber cables.

 FIG. 6 represents a top view of the pediment 14 of FIG. 1.

 FIG. 7 represents a splicing and organization operation according to the invention.

 FIG. 8 represents the final step of storing the cassette 4 in the connection box of FIG. 1.

Referring to Figure 1, the connection box for optical cables of the invention essentially consists of a frame 1 fixed against a plate 2 by means of screws (10, 11) arranged in the center of its bottom 130 backed by said plate 2. The plate 2 is substantially a square made integral with a base plate 3 receiving the cables A,
B, C with optical fibers. The cables A, B, C are received at the level of recesses 30 made in the base plate 3 to which they can be fixed and held in position by means of a mooring piece which is taken up on the outer envelope of the cable A, B or C. The optical cables can be of different types. These can be cables with a free structure or cables with a tight structure. The optical fibers are generally loosely arranged in tubes or in the grooves of a grooved rod. It can also advantageously be a fiber optic cable comprising a series of optical fibers arranged in an envelope like the cable described. in French patent application 9009627 filed by SILEC and the FRENCH STATE. Such a cable is formed of a plurality of modules surrounded by an envelope, each module comprising several optical fibers held by a retaining sheath. In this way, if each cable A, B or C comprises seven modules m for example, each module mj grouping five optical fibers for example, it is possible to fix the outer envelopes of the cables
A, B or C incoming and outgoing to the mooring pieces carried by the plate 3. Each module mj can advantageously have a particular color which will facilitate their identification as will appear in the following description.

 Referring to Figure 2, the frame 1 of the present invention is substantially like a rectangular parallelepiped, open on the side opposite to said face 130. Two faces (131, 132) adjacent to said bottom 13 of said frame 1, but being face, are internally provided with grooves 133, each upper and lower groove used for the insertion of a protective cassette 4 which will be detailed with the aid of FIGS. 3 and 4. The chassis 1 is surmounted by a template 14, curved backwards, placed above the open face of the chassis 1 in order to ensure that said modules mj have a minimum radius of curvature as will be explained later.

 The fiber optic junction box can be used for multiple applications, such as splicing, inserting couplers and coupling fibers, or multiplexing them. The junction box of the invention is advantageously placed in a vertical position but the lying or flat arrangements can be envisaged. The unilateral distribution of the box also makes it possible to circumscribe the sealing problems on one side of the outer envelope. It therefore reduces the size and cost.

 In addition, the frame 1 can be envisaged in PVC or in another plastic material, or even be produced for example by thermoforming.

 The protective cassette 4 is shown closed in FIG. 3.

It aims to receive the spliced optical fibers if it is a splicing box, or the couplers if it is a coupling box or any other type of connection. The cassette 4 is advantageously considered in PVC plastic or the like and produced for example by thermoforming. It is advantageously formed of two faces (41, 42) joined by a hinge 43. The two faces (41, 42) or plates are substantially rectangular, the face 41 serving as a cover, the face 42 serving as the bottom. On the side opposite to the hinge 43 is provided, for each face 41 and 42, a tongue (44a, 44b) fitting one into the other to ensure the closing of the cassette 4. The cassette 4 is bordered by a boss 45 along the periphery of each of its faces 41 and 42 in order to ensure the mechanical rigidity of each of its faces (41, 42). Bosses 46 and 47 can further improve the rigidity of the box.

 FIG. 4 represents a top view of an open cassette 4 according to the invention and therefore a detailed view of the other face 42 of this cassette. It also has a boss 45 on the periphery to also ensure the rigidity of this face and the bosses 48 and 49. The boss 48 is substantially placed at the center of the face 42 and extends perpendicular to the hinge 45 up to the vicinity of a core 49. This core 49 is substantially circular or oblong with a radius of curvature advantageously chosen to ensure the protection of the optical fibers in the cassette 4 by coiling around this core 49 for example.

On either side of the core 49, there are also provided jumpers
I for hanging excess fiber optic towers.

 The boss 48 on the contrary makes it possible to receive the splicing by bonding of a Velcro strip V as will be explained later. The tongues 44 and the hinge 45 of the closed cassette 4 slide in the grooves 133 of the chassis 1 thus ensuring the insertion of the splicing cassette 4 in the connection box.

 Figures 1 and 5 illustrate, after blooming of the modules m at the output of cables A, B or C, their distribution and access to the chassis 1. A simplification according to the invention of the distribution and identification of the input / output modules is due to the fact that the mid incoming modules are placed in a groove Re at the rear bottom of the chassis 1 while the outgoing modules mj are placed in a groove Rs at the rear bottom of the chassis 1. These two longitudinally extending grooves are separated by the chassis fixing strip 1 against the plate 2. More specifically, it is the plate 2 which closes the grooves Re and Rs in the rest position. The simple and modular design of the assembly offers the operator perfect accessibility during cabling and cable splicing operations.

 A simple elastic deformation of the chassis 1 allows the insertion or extraction of the modules (me, ms) as illustrated in the sectional view of FIG. 5 to access the groove Rs.

 At the outlet of the grooves (Re, R5), the modules (mi, m'j) emerge above the template 14 of the chassis 1. Then, the modules (mi, mj) are distributed by the operator by means of the grooved strip 140 carried by the template 14 illustrated in FIG. 6.

 Each groove 140k makes it possible to receive an input mk module and the output mBk module intended to be coupled (or else spliced or even multiplexed). A color identification system 141 makes it possible to group the modules (mi, mj) appropriately according to their destination.

A second locating means 142 makes it possible to identify the cables A, B, C, from which the modules originate or are intended.

 A return 20 of the plate 2 above the chassis 1 allows perfect protection of the modules until they are accessed in each cassette 4.

 According to a preferred embodiment of the invention, as illustrated in FIG. 8a, the operator then places the cassette 4 open on the support 5 held by a fixing bracket 61 which is unfoldable or orientable by 180 above the box. connection of the invention, this bracket 61 can for example be carried by the bracket 6 in its extension. This embodiment adapts in particular to a wall organization of the connection box, as suggested in FIG. 7.

 Its implementation can also be envisaged outside the splicing chamber, the bracket 61 being replaced by a tripod for example.

 The splice E is then made by the operator on the bench B simultaneously for the optical fibers of the same module mj as shown in FIG. 7a. The splice E is advantageously provided with a gripping strip V ′ which then easily hangs (FIG. 7b) on the strip V bonded to the boss 48 of the open cassette 4. These fixing tapes (V, V ') are, for example, of the type sold under the brand Velcro.

 The incoming module lengths m'j are then "coiled * around the core 49 and held by means of the jumper I, as shown in FIG. 7c, and the same operation is performed for the outgoing fibers (module mi) (see FIG. 7d In fact, a single coiling turn is sufficient. The cassette 4 can then be closed and stored in the frame 1, as illustrated in FIG. 8, by pivoting it in the vicinity of the fixing grooves 133 of FIG. tabs 44 and 43 then engage in two lower and upper grooves 133 of the chassis 1.

The cassette 4 is thus stored, occupying a minimum space and respecting an acceptable radius of curvature for the optical fibers (FIG. 8b).

 Optionally, it suffices to guide the excess modules (mi, m'i) length in the cassette 4 after the cassette 4 has been stored in the chassis. It naturally occupies the location around the core 49 which is intended for it.

 The compactness of the construction and the low cost of materials as well as the modularity of a connection box confer great flexibility of construction.

 In order to also meet the sealing requirements of such a storage and connection box, there is advantageously a cap 7 around the frame 1. This cap 7 is substantially a rectangular box open on a base 70. This base 70 comes s 'fit into the plate 3. In order to improve the seal, a tightening joint, not shown, and tightening screws allow the cover 7 to be closed.

 The junction box of the invention is characterized by simplicity of implementation and manufacturing at reduced cost.

Claims (12)

 1 - Protection and storage cassette for an optical fiber cable comprising means for receiving, for example, two ends of an optical fiber, means for storing the excess lengths of said optical fiber with an appropriate radius of curvature, cassette characterized in that it is essentially formed of at least two plates (41, 42), separated by a hinge (43), said plate (42) serving as the bottom, the plate (41) serving as a cover, said hinge (43) allowing the opening of the cassette (4).  2 - Cassette according to claim 1 characterized in that said bottom (42) comprises, in the vicinity of its center, a boss (48), said boss (48) being intended to receive the connection device.  3 - Cassette according to one of claims 1, 2, characterized in that said bottom (42) comprises, in the vicinity of its center, a core (49) intended to receive and protect the excess lengths of optical fibers.  4 - Cassette according to one of claims 1 and 2 characterized in that, on either side of the core (49), are arranged jumpers (I) for hooking excess lengths of optical fibers.  5 - Cassette according to one of claims 1 to 3, characterized in that each plate (41, 42) has a tongue (44a, 44b) on the side opposite the hinge (43) separating them, said tabs fitting to close the cassette (4).  6 - Cassette according to one of claims 1 to 4, characterized in that it is obtained by thermoforming of a plastic material such as PVC or other.  7 - Connection device for fiber optic cable allowing the shuffling and / or distribution of cables two by two, device characterized in that it essentially comprises a chassis (1) grooved (133) on two opposite faces, the grooves (133) cooperating in pairs to receive at least one cassette (4) according to one of claims 1 to 5, the tabs (44as 44b) and the hinge (43) allowing the cassette (4) to slide in the grooves (13) and to be held in the chassis (1).  8 - Device according to claim 6, characterized in that the frame (1) is a substantially rectangular box open following a plane perpendicular to said grooves (13) to allow the sliding and the extraction of cassettes (4).  9 - Device according to one of claims 6 and 7, wherein the number (i) of grooves (133) is a function of the number of cassettes (4) and therefore the number of elementary cables (mi) to be connected and / or distributed .  10 - Device according to one of claims 6 to 8, characterized in that the frame (1) is advantageously obtained by thermoforming of a plastic material such as PVC or other.  It - Device according to one of claims 6 to 9, characterized in that the chassis (1) is surmounted by a template (14) substantially curved towards the rear in order to apply to the modules (mi, mj) ( incoming elementary cables) or modules (m'i, m'j) (outgoing elementary cables) a suitable radius of curvature, this template (14) comprising means for guiding said incoming and / or outgoing modules, grouping means, means of location.  12 - Device according to one of claims 6 to 10, characterized in that the incoming and outgoing modules (mi, m'j) are advantageously arranged in two grooves (Re, Rs) respectively produced externally to said chassis (1) of the side opposite to the opening, said modules being introduced therein by elastic deformation of said chassis (1).  13 - Device according to one of claims 10 and 11 characterized in that the locating means comprise grooves (140k), each groove (k) corresponding to a module (k) of a fiber optic cable.