GB2354338A

GB2354338A - Fibre optic splice shelf with cable storage below

Info

Publication number: GB2354338A
Application number: GB9918152A
Authority: GB
Inventors: Alain Wambeke; Erik Peeters; Danny Thijs
Original assignee: Raychem NV SA
Current assignee: Commscope Connectivity Belgium BVBA
Priority date: 1999-08-03
Filing date: 1999-08-03
Publication date: 2001-03-21
Also published as: GB9918152D0

Abstract

A shelf for splicing and/or patching fibre optic cables (20) comprises a base plate (2) for mounting splicing means (3) and/or patching means (4). The shelf is provided with cable retainers (5) for retaining excess cable on the bottom side (B) of the base plate (2). Preferably, the cable retainers (5) comprise retaining plates (6) extending substantially parallel to the base plate (2) at a distance of less than two cable diameters.

Description

2354338 Fibre Optic Shelf With Cable Storage The present invention relates

to a shelf for splicing and/or patching fibre optic cables. More in particular, the present invention relates to a shelf for splicing and/or patching fibre optic cables, comprising a base plate for mounting splicing means and/or patching means on one side thereof.

Shelves of this kind are used in optical fibre distribution systems. Typically, the shelves are stacked in a rack and are arranged as drawers which can, at least partially, be pulled out of the rack so as to allow easy access to the devices installed on the shelf Such devices may for example comprise splice trays for splicing the cable into a plurality of constituent cables or fibres, or patching panels for connecting the cable(s) or fibres to so-called "pigtails" or further cables, or both splice trays and patching panels. The rack, typically accomodated in a housing so as to produce a fibre optic cable cabinet, often also comprises storage spools, splice supports and other auxiliary devices. Excess cable allowing the shelves to be pulled forward is stored in the rack behind the shelves.

The work involved in splicing and patching fibre optic cable requires great precision, as the optical fibres are thin and delicate. Also, incorrect splicing or patching leads to large signal losses, making the cable or fibre involved virtually useless. It is therefore imperative for an operator to gain easy access to the shelf he is working on. The drawer arrangement described above does allow access to the shelf. However, in such an arrangement the shelf remains within the rack or cabinet, as the cable (or sometimes cables) connecting the shelf to the rack (the so-called excess cable or cable slack) has a limited length. Consequently, the operator's working space is limited due to the presence of cable bundles, cable spools and other devices within the rack.

It follows that there is a need for easier access to fibre optic shelves. The present inventors have found that the limited access is primarily due to the restricted cable slack, which prevents the shelves from being taken out of the rack. That is, the length of excess cable which can be stored in the rack is necessarily limited due to space restrictions and the requirement of being able to bring a cable back into its stored position behind the shelf. However, the distance over which the shelf can be moved from its original position is determined by this length of excess cable. Prior art shelves do not offer a solution for this problem.

The invention seeks to overcome these and other disadvantages of the prior art and to provide a shelf for splicing and/or patching fibre optic cables, comprising a base plate for mounting splicing means and/or patching means on one side thereof, which shelf according to the present invention is characterised by cable retainers for retaining excess cable on the other side of the base plate.

By providing cable retainers which are capable of retaining excess cable on the side of the base plate not carrying the splice trays or patch panels, the free surface of the base plate may be used to accomodate the excess cable. In this way, it is possible to accomodate a greater length of excess cable than is possible in the rack. Therefore, by storing the slack cable at the shelf rather than in the rack, the shelf may be moved further from the rack, providing easier access. It will also be appreciated that the excess cable itself is much easier to access when stored at the shelf and may thus easily be uncoiled when the shelf is removed and coiled up when the shelf is placed back.

Preferably, the cable retainers are arranged for retaining successive cable loops along the plane of the base plate. That is, when the excess cable is stored in loops, these loops are stored flat against the surface of the base plate, providing a compact storage. In this way, the cable storage does not take up much space, resulting in a compact arrangement.

Advantageously, the cable retainers comprise retaining plates extending substantially parallel to the base plate at a distance of less than two cable diameters. The arrangement parallel to the base plate keeps the cable in the plane of the base plate, while the spacing of less than two cable diameters, and obviously at least one cable diameter, prevents the stacking of cable loops, thus ensuring a single layer storage. This, in turn, facilitates the coiling and uncoiling of the cable and ensures a compact arrangement.

Advantageously, a retaining plate is part of a hook mounted at an edge of the base plate. The hook, preferably constituted by a piece of material bent at least once over an angle of 90 degrees, comprises a retaining plate retaining the cable and a support plate supporting the retaining plate.

The support plate may be mounted on the particular side of the base plate, or on a side wall of the plate. Preferably, the cable retainers are comprised of hooks mounted near three edges of the base plate and a cable strap near a fourth edge.

Advantageously, the base plate is provided with a through hole for passing a cable from one side to the other side of the base plate. This obliterates the need for the cable to go around the edge of the base plate, thus providing better protection of the cable against damage and making the arrangement more compact. Preferably, the through hole is located near an edge of the base plate so as to allow the cable loop to use the surface of the base plate to the greatest extent possible without bending the cable.

Advantageously, a cable termination is located at the through hole, thus providing strain relief for the cable.

The present invention will further be described with reference to an exemplary embodiment illustrated in the accompanying drawings, in which:

Fig. I shows, in perspective, a shelf according to the present invention, Fig. 2 shows, in perspective, the shelf of Fig. I as seen from below, Fig. 3 shows, in side view, a cable retainer of the shelf of Fig. 1, Fig. 4 shows, in side view, an alternative cable retainer, Fig. 5 shows, in front view, a rack in which shelves are fitted.

The shelf I shown by way of non-limiting example in Fig. I comprises a base plate 2 on which, in this particular embodiment, both splice trays 3 and a patching panel 4 are mounted. As is well known in the art, the splice trays 3 serve to store and retain cable splices (not shown), while the patch panel 4 serves to accomodate connectors (not shown) for connecting the cable splices to further cables, which may include so-called "pig tails".

The base plate 2 has upstanding edges constituting side walls 9, a back wall 10 and a front wall 11.

These walls which are integral with the base plate 2 so as to create a box-like structure which can be used as a drawer in a optical fibre management rack. The patching panel 4 is accomodated in the front wall 11. Mounting brackets 12 are fixed to the side walls 9. The side of the base plate 2 on which the splice trays 3 are mounted, and which normally faces up when in use, is designated "A" in Fig. 1.

In accordance with the present invention, the shelf I is provided with cable retainers so as to be able to store a cable at the opposite or bottom side of the base plate 2 (the bottom side is designated "B" in Fig. 2). In the embodiment of Fig. 1, hook-shaped cable retainers 5 are mounted on the walls 9 and 10 of the base plate 2 and each comprises a retaining plate which extends parallel to the bottom side B of the base plate 2, as shown in Fig. 2. For practical reasons, no hook-shaped cable retainer is mounted on the front wall accomodating the patch panel 4. Instead, holes 13 are provided for fixing a cable strap. Of course it would be possible to replace all hook-shaped cable retainers 5 by cable straps and still provide a cable storage at the bottom side of the base plate, maintaining most of the advantages of the present invention. However, as will be explained later with reference to Figs. 3 and 4, the particular shape of the cable retainers influences the way a cable is stored and the dimensions of the shelf.

An opening or through-hole 14 is provided in the base plate 2 for passing a cable (not shown) from the bottom side B to (the splice trays 3 at) the other side A. Suitably, a cable termination 15 may be fitted at the through hole 14 and may preferably mounted on the base plate 2.

As shown in Fig. 3, in a preferred embodiment a cable retainer 5 is constituted by a piece of material, preferably metal but possibly plastic, bent over 90 degrees so as to form a hook-shaped or L-shaped retainer having a retaining plate 6 and a mounting plate 7. The retaining plate 6 extends substantially parallel to the base plate 2, while the mounting plate 7 is surface mounted on a wall 9.

This is the embodiment shown in Figs. I and 2. It will be seen from Fig. 3 that the retaining plate 6 extends over several (e.g. four) cable diameters, so as to be able to accomodate several cable loops.

The spacing between the retaining plate 6 and the base plate 2 is preferably chosen to lie between one and two times the diameter of the cable 20, more preferably about 1.5 times the diameter. This spacing allows the cable to be easily fitted between the retaining plate 6 and the base plate 2 while preventing cable loops to stack. The cable will therefore be accomodated in spiral loops and in a single layer, thus providing a very compact storage.

A compact storage may also be obtained by the cable retainers of Fig. 4, which are constituted by by a piece of material, preferably metal but possibly plastic, bent over 90 degrees twice so as to form a sharp hookshaped or U-shaped retainer having a retaining plate 6 and a mounting plate 7 which both extend substantially parallel to the base plate 2.

The rack schematically shown in Fig. 5 comprises several shelves 1, mounted on vertical bars 53 and 54. A further vertical bar 52 supports cable spools 5 1. In accordance with the present invention each shelf I is provided with a cable storage so as to allow the shelf to be taken out of the rack and be put on a work surface for easy access.

It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above and that many additions and modifications can be made without departing from the scope of the invention as defined in the appending claims.

Claims

Claims

I. Shelf for splicing and/or patching fibre optic cables (20), comprising a base plate (2) for mounting splicing means (3) and/or patching means (4) on one side (A) thereof, characterised by cable retainers (5) for retaining excess cable on the other side (B) of the base plate (2).
2. Shelf according to claim 1, wherein the cable retainers (5) are arranged for retaining successive cable loops along the plane of the base plate (2). 10
3. Shelf according to claim I or 2, wherein the cable retainers (5) comprise retaining plates (6) extending substantially parallel to the base plate (2) at a distance of less than two cable diameters.
4. Shelf according to claim 3, wherein a retaining plate (6) is part of a hook mounted at the 15 edge of the base plate (2).
5. Shelf according to claim 4, wherein the cable retainers (5) are comprised of hooks mounted at three edges of the base plate (2) and a cable strap at a fourth edge.
6. Shelf according to the preceding claims, wherein the base plate (2) is provided with a through hole (14) for passing a cable (20) from one side (B) to the other side (A) of the base plate.
7. Shelf according to claim 6, wherein the through hole (14) is located near an edge of the base plate (2). 25
8. Shelf according to claim 6 or 7, wherein a cable termination (15) is located at the through hole (14).
9. Shelf according to any of the preceding claims, wherein a splice tray (3) is mounted on the 30 base plate (2) on the side facing away from the cable retainers (5).
10. Shelf according to any of the preceding claims, wherein a patch panel (4) is mounted on the base plate (2) on the side (A) facing away from the cable retainers (5).
11. Shelf according to any of the preceding claims, wherein an optical fibre cable (20) is prefitted.
12. Rack (50) for fibre optic cable management, provided with a shelf (1) according to any of 5 the preceding claims.