Abstract:
The invention relates to a cable housing ( 1 ) for receiving optical fibers and fibers ( 28   b ) of a fiber optic cable ( 28   a ), comprising at least one locking element ( 15   a   , 15   b ) and at least one passage ( 16   a   , 16   b ) for the fibers ( 28   b ), wherein the locking element ( 15   a   , 15   b ) can be moved into at least one open and one closed state, wherein the fibers ( 28   b ) are held in the passage ( 16   a   , 16   b ) in the closed state, and a method for receiving optical fibers and fibers ( 28   b ) of a fiber optic cable ( 28   a ) in a cable housing ( 1 ), comprising the following process steps: a) disposing the locking element or elements ( 15   a   , 15   b ) in the open state; b) winding the fibers ( 28   b ) about the passage ( 16   a   , 16   b ); and c) disposing the locking element or elements ( 15   a   , 15   b ) in the closed state.

Description:
This application is a National Stage Application of PCT/EP2009/001304, filed 24 Feb. 2009, which claims benefit of Serial No. 2008901578, filed 2 Apr. 2008 in Australia and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. 
     BACKGROUND 
     The present invention relates to a cable housing and to a method for holding optical fibers or fibers of an optical fiber cable. 
     The process of binding together two ends of optical fibers is known as splicing, resulting in a “splice” being created between the two fibers. Splices are particularly susceptible to damage from shock, stress, dynamic loading and the like. Modern optical fiber networks can contain cables comprising hundreds of optical fibers and a correspondingly large number of individual splices each of which needs to be protected against the aforementioned mechanical disturbances. 
     Housings such as splice trays, for the containment of optical fibers and cables, particularly in the vicinity of splices, for their protection against undesirable mechanical disturbances, are known. However, handling difficulties arise during the placement of new cables into such housings with cables already placed therein. Further, devices used to retain cables within the housings tend to be obtrusive when placing cables onto the tray. 
     SUMMARY 
     The invention is based on the technical problem of providing a cable housing and a method for holding optical fibers or fibers of an optical fiber cable, by means of which the handling of optical fibers and fibers is improved. 
     For this purpose, the cable housing for holding optical fibers and fibers of an optical fiber cable has at least one latch and at least one passageway for the fibers, wherein the latch can be moved at least to an open condition and a closed condition, or position, wherein the fibers are held in the passageway in the closed condition. The change from the open condition to the closed condition preferably takes place in this case by movement of the latch transversely with respect to the passageway. In the open condition, the passageway represents an open channel, and in the closed condition it represents a closed channel, thus preventing undesirable movements of the fibers (for example upward). In order to accommodate new fibers, the latch is then moved to the open condition, the fibers are inserted, the latch is then moved back again to the closed condition. It should be noted that the wording “a least one latch” is also intended to cover just one latch, although the cable housing preferably has two latches. 
     In one preferred embodiment, the cable housing has a mount which is arranged on a base of the cable housing, wherein the latch is attached to the mount, and wherein the latch can be moved by means of a sliding movement along the mount transversely with respect to the passageway. 
     In a further preferred embodiment, the latch has a cover plate which, in the closed state, closes the passageway at the top. 
     In a further preferred embodiment, the latch has a connector for connection to the mount. 
     In a further preferred embodiment, the connector has grooves in the longitudinal direction and the mount has protrusions in the longitudinal direction, which allows the latch to be held detachably in intermediate positions between the open state and the closed state. In this case, it should be noted that the individual groove does not extend in the longitudinal direction, but that the grooves are arranged distributed in the longitudinal direction. Furthermore, it should be noted that, conversely, the connector may also have the protrusions, and the latch may have the grooves. 
     In one preferred embodiment, the passageway is bounded by a wall structure which projects from a base of the housing, wherein the wall structure comprises an inner wall and an outer wall, and wherein the inner wall is curved in order to guarantee a minimum bending radius for the fibers. 
     In a further preferred embodiment, the latch has a flange, which strikes against the inner wall in the closed state. The cable housing is preferably in the form of a splice cassette. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in more detail in the following text with reference to one preferred exemplary embodiment. In the figures: 
         FIG. 1  is a an exploded view of a cable housing; 
         FIG. 2  is a perspective view of the housing shown in  FIG. 1 ; 
         FIG. 3  is a top view of the housing shown in  FIG. 1 ; 
         FIG. 4  is a bottom view of the housing shown in  FIG. 2 ; 
         FIG. 5  is a perspective view of a latch of the housing shown in  FIG. 1 ; and 
         FIG. 6  is a further top view of the housing shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     A cable housing  1  is shown in  FIGS. 1 to 4  as including a substantially flat base  2  which defines a work area  3 , extending between side regions  4   a ,  4   b  and ends  5   a ,  5   b , adapted to retain cable thereon. 
     The housing  1  is provided with a number of anchoring sites  7  disposed at cable entry/exit regions  8 , which may be used with cable ties (not shown), or similar, to secure cables entering and exiting the housing. 
     The housing  1  is further provided with integrally formed side rails  9   a ,  9   b  extending along side regions  4   a ,  4   b  of the work area  3 . The rails  9   a ,  9   b  span substantially the length of, and are disposed along the edge of, the work area  3 . Opposite ends sections  10  of each rail  9   a ,  9   b  converge inwardly and merge into the anchoring sites  7 . The side rails  9   a ,  9   b  are provided with notches  11  adapted to mate with clips of an adjacent housing (not shown), enabling adjacent housings to be stacked and secured relative to each other. The side rails  9   a ,  9   b  of the housing  1  are provided with clips  12  (cf.  FIG. 2 ), at an underside  13  (cf.  FIG. 4 ), to engage in associated notches  11  of an adjacent housing. 
     The side rails  9   a ,  9   b  are also provided with protruding lips  14  extending inwardly over the work area  3  of the housing  1 . The protruding lips  14  assist in capturing optical fibers, for example, which may be looped around the work area  3 , to the housing  1 . 
     To further assist in securing the cable in place, the housing  1  is provided with latches  15   a ,  15   b  which are arranged to close off passageways  16   a ,  16   b  (cf.  FIG. 6 ), through which the fibers  28   b  pass. As particularly shown in  FIG. 5 , each latch  15   a ,  15   b  is formed of an arcuate cover plate  17 , arranged substantially parallel to the work area  3  of the base  2 , and an elongate connector  18  which is arranged to interfit with a mount  19  projecting upwardly from the base  2  of the housing  1 . The connector  18  and mount  19  have a series of interfitting grooves  20  and protrusions  21  that allow the latch  15   a ,  15   b  to be releasably held at different positions along the length of the mount  19 . 
     A grip pad  22  is provided on the latch  15   a ,  15   b  to facilitate sliding movement of the connector  18  with respect to the mount  19  between the different positions. Alternatively, the latch  15   a ,  15   b  could be lifted clear of the mount  19  and then moved to a new position and reconnected with the mount  19 . 
     In the arrangement shown in  FIG. 6 , a cable  28   a  is fastened to the anchoring site  7  by way of a cable tie (not shown), for example. The latches  15   a ,  15   b  are in an open condition, which allows fibers  28   b  of the cable  28   a  to be looped around the curved inner walls  23  and under the lips  14 . The lips  14  prevent the fibers  28   b  from lifting away from the base  2  and spilling over the side rails  9   a ,  9   b.    
     The fibers  28   b  are freely looped into the passageways  16   a ,  16   b . Each passageway  16   a ,  16   b  is defined by wall structure  25   a ,  25   b  which projects from the base  2  of the housing  1  and which includes an inner wall  23 , defining a minimum bend radius for fibers  28   b  passing through the passageway  16   a ,  16   b , and outer wall  24 . The outer wall  24  is located adjacent an end  5   a ,  5   b  of the housing  1 , while the inner wall  23  is positioned closer to a centre of the housing  1 . As can be seen in  FIG. 6 , the latches  15   a ,  15   b  have a relatively low profile relative to the base  2  and, additionally, are positioned inwardly of the wall structure  25   a ,  25   b  and away from a periphery of the housing  1 , which thereby allows the fibers  28   b  to be freely looped into the passageways  16   a ,  16   b  without obstruction. 
     Once the fibers  28   b  have been arranged in the described manner, the ends of the individual fibers  28   a  are joined together using optical fiber splicers (not shown). 
     With the fibers  28   b  seated in the passageway  16   a , for example, the latch  15   a  can be moved to close the passageway  16  by sliding the latch  15   a  along the mount  19  transversely to the passageway  16   a  and parallel to the base  2  so that the cover plate  17  covers the passageway  16   a  to thereby secure the fibers  28   b  to the housing  1 . The result is the arrangement shown in  FIG. 3 . The cover plate  17  is also provided with a flange  26  which abuts the inner wall  23  when the latch  15   a  is in the fully closed condition, in order to restrict further sliding movement of the latch  15   a . The flange  26  includes protrusions  32   a ,  32   b  (cf.  FIG. 5 ) arranged for resilient engagement with corresponding notches  6   a ,  6   b  of the inner wall  23  to resiliently secure the latch  15   a  to the inner wall  23 . 
     The latch  15   b  is essentially a mirror image of the latch  15   a  and like reference numerals are used to denote like parts. As can be seen, the latch  15   b  is shown in the open condition with the leading edge of the cover plate  17  abutting the inner wall  23  of the base  2  so that the passageway  16   b  is open to receive fibers  28   b.    
     The fibers from a second cable (not shown) are looped around the curved walls  23  in an opposite direction to that of the fibers  28   b  of the first cable  28   a  so that the fibers would present themselves to the splices at opposite ends of the cable housing  1 . 
     As may be appreciated from above, one particular advantage conveyed by the embodiments of the invention herein described, is that the latch  15   a ,  15   b  is slidably moveable between open, closed and semi-retracted conditions. The slidable movement removes the latch  15   a ,  15   b  from above the passageway  16   a ,  16   b , without it becoming an obstruction during the process of looping fibers  28   b  on or off the housing  1 . Furthermore, the semi-retracted condition provides partial restraint for cable  28   a  and the fibers  28   b  already within the passageway  16   a ,  16   b , whilst enabling access for the addition of more cables  28   a  and fibers  28   b  thereto. 
     Another advantage is provided by the inner walls  23 . Due to the fragility of some cables  28   a  and fibers  28   b , it is desirable that there be protection for cables  28   a  and fibers  28   b  against bending below its minimum design bend radius. The inner wall  23 , having a radius of curvature at least as large as the minimum bend radius of a cable or fiber placed thereagainst, should provide some protection for cable or fiber being secured to the housing. 
     The cable housing  1  also includes an outer cover plate  29  (cf.  FIG. 1 ) shaped to fit over the work area  3  of the body  2  to capture and protect the above-described components within the housing  1 . The outer cover plate  29  includes a planar body section  30  (cf.  FIG. 2 ) of corresponding dimensions to that of the work area  3 . The outer cover plate  29  includes opposed rails  31  that extend outwardly from the body section  30  in common directions, along respective sides of the plate  29 . The rails  31  are shaped to fit over respective rails  9   a ,  9   b  when the cover plate  29  is coupled to the cable housing  1 . The plate  29  includes protrusions (not shown) arranged for resilient engagement with corresponding notches  11  of the rails  9   a ,  9   b  to resiliently secure the cover plate  29  to the cable housing  1 . 
     The embodiments have been described by way of example only and modifications are possible within the scope of the invention. 
     Throughout this specification and claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. 
     The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavor to which this specification relates. 
     LIST OF REFERENCES 
     
         
           1 . cable housing 
           2 . base 
           3 . work area 
           4   a . side region 
           4   b . side region 
           5   a . end 
           5   b . end 
           6   a . notch 
           6   b . notch 
           7 . anchoring sites 
           8 . cable entry/exit regions 
           9   a . side rail 
           9   b . side rail 
           10 . end sections 
           11 . notches 
           12 . clips 
           13 . underside 
           14 . lips 
           15   a . latch 
           15   b . latch 
           16   a . passageway 
           16   b . passageway 
           17 . cover plate 
           18 . connector 
           19 . mount 
           20 . grooves 
           21 . protrusions 
           22 . ribbing 
           23 . inner wall 
           24 . outer wall 
           25   a . wall structure 
           25   b . wall structure 
           26 . flange 
           28   a . cable 
           28   b . fibers 
           29 . outer cover plate 
           30 . body section 
           31 . side rails 
           32   a . protrusion 
           32   b . protrusion