Abstract:
The invention relates to an apparatus ( 1 ) for sealing small tubes ( 11, 12 ) of a blown-fiber cable ( 10 ) on insertion into a collar ( 50 ), comprising a sealing element ( 2 ), a splitting element ( 3 ), a bundling element ( 4 ) and at least one covering element, with the sealing element ( 2 ) having a number of seals ( 24 ) corresponding to the number of small tubes ( 11, 12 ), with the splitting element ( 3 ) being arranged on the cable side before the sealing element ( 2 ), and with the bundling element ( 4 ) being arranged on the collar side behind the sealing element ( 2 ), and to an associated method.

Description:
[0001]    This application claims benefit of Ser. No. 10 2008 037 126.2, filed 8 Aug. 2008 in Germany and which application is incorporated herein by reference. To the extent appropriate, a claim of priority is made to the above disclosed applications. 
       BACKGROUND 
       [0002]    The invention relates to an apparatus and a method for sealing small tubes of a blown-fiber cable on insertion into a collar. 
         [0003]    Collars for glass fiber cables have two fundamentally different sealing systems, specifically elastomer cable seals in the housing lower part of the collar, or else shrink sleeves. 
         [0004]    Recently, novel types of glass fiber cables have been developed, so-called blown-fiber cables. These have a multiplicity of small tubes through which fibers can be blown subsequently by means of compressed air. These cables are extremely rigid, as a result of which their direct insertion into the collar leads to difficulties in subsequent movement of the collar. 
         [0005]    In order to solve the problem, it is feasible to partially strip the cable and to insert the small tubes directly into the collar. The small tubes could then be protected outside the collar by a flexible tube, which is then passed to the collar. However, this leads to sealing problems on the collar if the flexible tube is damaged. 
       SUMMARY 
       [0006]    The invention is based on the technical problem of providing an apparatus and a method for sealing small tubes of a blown-fiber cable on insertion into a collar. 
         [0007]    For this purpose, the apparatus for sealing small tubes of a blown-fiber cable on insertion into a collar comprises a sealing element, a splitting element, a bundling element and at least one covering element, with the sealing element having a number of seals corresponding to the number of small tubes, with the splitting element being arranged on the cable side before the sealing element, and with the bundling element being arranged on the collar side behind the sealing element. This makes it possible to seal each small tube including the core individually, in such a way that no moisture can penetrate into the collar along the small tubes. The spread-out cable is then combined again in a compact form, by the bundling element. In this case, the covering element is located at least over the sealing element, and extends as far as the collar. In this case, it should be noted that the sealing element may also have more seals than small tubes, in which case the unused seals must then be closed, for example by means of a membrane. The sealing element is preferably composed of an elastomer. Furthermore, the splitting element, the sealing element and the bundling element are preferably connected to one another, for example by latching, adhesive bonding or screwing. 
         [0008]    The seals are preferably arranged concentrically on the sealing element in which case, furthermore, at least two rings of seals preferably exist. This allows the small tubes to be routed sufficiently far apart from one another, thus simplifying the handing when passing the small tubes through the sealing element. 
         [0009]    In a further preferred embodiment, the seals have outward bulges in the form of truncated cones on the collar side. This results in a good sealing effect in a very simple manner, even if the small tubes have different diameters. Alternatively, the outward bulges can also be hollow-cylindrical. 
         [0010]    In a further preferred embodiment, the covering elements are in the form of two elements with a cap and a tubular attachment, with the caps surrounding the sealing element. The two caps can in this case be connected to one another in a moisture-tight manner for example by latching, screwing, adhesive bonding or in some other way. The tubular attachment on the collar side is in this case used for insertion into the collar, with the tubular attachment being sealed by means of an elastomer seal on insertion into the collar, with the tubular attachment on the cable side being used for connection by means of a shrink sleeve to the cable sheath or to a flexible tube which is pushed on instead of it. When using a flexible tube, a further shrink sleeve is then preferably used for connection of the cable sheath and flexible tube. 
         [0011]    The outer small tubes are preferably shorter than the inner small tubes, such that the inner small tubes are passed through the sealing element first of all followed by the outer small tubes, thus making handling easier. The small tubes are then cut to approximately the same length again within the collar at a later time. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0012]    The invention will be explained in more detail in the following text with reference to one preferred exemplary embodiment. In the figures: 
           [0013]      FIG. 1  shows an exploded illustration of an apparatus for sealing small tubes of a blown-fiber cable, 
           [0014]      FIG. 2  shows a perspective illustration of a blown-fiber cable, 
           [0015]      FIG. 3   a  shows a plan view of the cable side of a splitting element, 
           [0016]      FIG. 3   b  shows a side view of the splitting element, 
           [0017]      FIG. 3   c  shows a section illustration of the splitting element along the section X-X in  FIG. 3   a,    
           [0018]      FIG. 3   d  shows a plan view of the collar side of the splitting element, 
           [0019]      FIG. 3   e  shows a perspective illustration of the splitting element from the cable side, 
           [0020]      FIG. 3   f  shows a perspective illustration of the splitting element from the collar side, 
           [0021]      FIG. 4   a  shows a cable-side plan view of a sealing element, 
           [0022]      FIG. 4   b  shows a side view of the sealing element, 
           [0023]      FIG. 4   c  shows a collar-side plan view of the sealing element, 
           [0024]      FIG. 4   d  shows a perspective illustration of the sealing element from the cable side, 
           [0025]      FIG. 4   e  shows a perspective illustration of the sealing element from the collar side, 
           [0026]      FIG. 5   a  shows a cable-side plan view of a bundling element, 
           [0027]      FIG. 5   b  shows a sectional illustration along the section X-X shown in  FIG. 5   a,  and 
           [0028]      FIG. 6  shows a perspective illustration of the apparatus for sealing a blown-fiber cable on insertion into a collar. 
       
    
    
     DETAILED DESCRIPTION  
       [0029]    The apparatus  1  shown in  FIG. 1  for sealing small tubes  11 ,  12  of a blown-fiber cable  10  (see  FIG. 2 ) comprises a sealing element  2 , a splitting element  3 , a bundling element  4  and two covering elements, which are in the form of elements  5 ,  6  with a cap  7  and a tubular attachment  8 . The apparatus  1  is used to seal a blown-fiber cable  10  by means of elastomer seals, on insertion into a collar. 
         [0030]    In a first step, the blown-fiber cable  10  is partially stripped, with the outer small tubes  11  being cut off to be shorter than the inner small tubes  12 . By way of example, the distance D from the end face of the outer small tubes  11  to the sheath  13  of the blown-fiber cable  10  is approximately 2-3 m, while in contrast the distance d between the end faces of the inner small tubes  12  and the end faces of the outer small tubes  11  is about 0.1 m. 
         [0031]    The small tubes  11 ,  12  are then passed through a flexible tube  20  and two shrink sleeves  21  (see  FIG. 6 ). In this case, one shrink sleeve is used for connection of the sheath  13  of the blown-fiber cable  10  to the flexible tube  20 , and the other shrink sleeve  21  is used for connection of the flexible tube  20  to the tubular attachment  8  of the element  5 . 
         [0032]    In the next step, the small tubes  11 ,  12  are passed through the tubular attachment  8  of the element  5 . 
         [0033]    The inner small tubes  12  are then first of all passed into openings  31  in the splitting element  3 . The concealed, centrally located core of the blown-fiber cable  10  is passed through a central opening  32 . The openings  31  are in this case arranged concentrically around the opening  32 . Once the inner small tubes  12  have been passed through, the outer small tubes  11  are then passed through openings  33 . The openings  33  are likewise arranged concentrically around the opening  32 . Rounded half-open guide elements  34  are arranged before each of the openings  31 ,  33  and make it easier to insert the small tubes  11 ,  12  (see  FIGS. 3   a,    3   f ). As can be seen in particular from  FIG. 3   e,  the openings  31 ,  32  and  33  lie on three different planes. Cylindrical guides  35  are located behind the openings  32  and  31  and guide the core and the inner small tubes  12  to the plane of the openings  33 , as can be seen particularly well in  FIG. 3   f.  Furthermore, the splitting element  3  has a circumferential edge  36 , which clasps the sealing element  2 . 
         [0034]    In the next step, the inner small tubes  12  including the core, and then the outer small tubes  11 , are passed through seals  24 . The seal  24  for the core is in this case arranged centrally, with the seals  24  for the inner small tubes  12  being arranged concentrically around the seal  24  for the core. The seals  24  for the outer small tubes  11  are likewise arranged concentrically. For this purpose, the seals  24  have openings on the cable side, which openings are aligned with the openings  31 - 33  in the splitting element  3 . On the collar side, the seals  24  have outward bulges  25  in the form of truncated cones, which then surround the small tubes  11 ,  12  in a moisture-tight manner. The outward bulge  25 , which is in the form of a truncated cone, for the core is in this case somewhat longer than the outward bulges for the small tubes  11 ,  12 . In order to make it easier to insert the small tubes  11 ,  12  and the core, depressions  26  in the form of funnels are arranged before the openings on the cable side. The sealing element  2  is in this case preferably formed from an elastomer material. 
         [0035]    The small tubes  11 ,  12  including the core are then passed through the bundling element  4 . The bundling element  4  can in this case be in the form of a separate component, which is pressed into the element  6  (see  FIG. 1 ) or else may be in the form of an integral component of the element  6 . The bundling element  6  has webs  27  which support the bundling element  4  (see  FIG. 5   a ) on the cap  7  of the element  6 . Furthermore, the bundling element  4  has a central aperture opening  28 , into which the inner small tubes  12  are inserted. Furthermore, the bundling element  4  has annular segments  29  which are separated from one another by webs  30 , with the annular segments  29  tapering in the direction of the tubular attachment  8 , such that the outer small tubes  11  are guided more densely to the inner small tubes  12  in order then to continue as a compact bundle in the tubular attachment  8  (see  FIG. 5   b ). 
         [0036]    Finally, the two caps  7  are joined together and are connected to one another in a sealed form, and the tubular attachment  8  of the element  6  is inserted through an elastomer seal  40  of a collar  50 , a part of which is illustrated in  FIG. 6 . The collar  50  has a housing lower part  51  which has detachable attached annular segments  52 . A holding element  53  is screwed to the housing lower part  51  and comprises an annular section  54  through which the tubular attachment  8  is passed. The function of the holding element  53  is in this case, in particular, to mechanically hold the tubular attachment  8 . 
         [0037]    If moisture enters the flexible tube through one of the shrink connections or as a result of damage to the flexible tube, then the sealing element  2  prevents this moisture from entering the collar  50 . 
       LIST OF REFERENCE SYMBOLS 
       [0038]      1  Apparatus 
         [0039]      2  Sealing element 
         [0040]      3  Splitting element 
         [0041]      4  Bundling element 
         [0042]      5 ,  6  Elements 
         [0043]      7  Cap 
         [0044]      8  Tubular attachment 
         [0045]      10  Blown-fiber cable 
         [0046]      11  Outer small tube 
         [0047]      12  Inner small tube 
         [0048]      13  Sheath 
         [0049]      20  Flexible tube 
         [0050]      21  Shrink sleeve 
         [0051]      24  Seals 
         [0052]      25  Outward bulges 
         [0053]      26  Funnel-shaped depressions 
         [0054]      27  Webs 
         [0055]      28  Central aperture opening 
         [0056]      29  Annular segments 
         [0057]      30  Webs 
         [0058]      31 - 33  Openings 
         [0059]      34  Guide elements 
         [0060]      35  Cylindrical guide 
         [0061]      36  Circumferential edge 
         [0062]      40  Elastomer seal 
         [0063]      50  Collar 
         [0064]      51  Housing lower part 
         [0065]      52  Annular segments 
         [0066]      53  Holding element 
         [0067]      54  Annular section