Abstract:
A seal assembly is provided to seal the area between a cable, containing optic fibers for example, and the terminal end of a conduit through which the cable runs. The seal assembly comprises an area of a resilient material and a supporting structure. The seal assembly, encompassing a cable, fits into and seals a standard conduit opening/hole in a cabinet or enclosure.

Description:
CLAIMING BENEFIT OF PRIOR FILED U.S. APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 60/866,890 filed on Nov. 22, 2006. The contents of this document are hereby incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to improvements to apparatuses and methods for forming a seal around cables that are passed through an opening of a sealed enclosure. 
       BACKGROUND OF THE INVENTION 
       [0003]    Cables and particularly fiber optic cables have become a preferred transmission system for telecommunication and data communication. Fiber optic cables, for example, can contain many strands of optic fibers. These cables are generally installed underground inside a conduit. The conduit and the cable that runs through it are often laid in trenches and can extend for long distances. For purposes of maintenance, upgrading, and connection to the fiber optics, underground vaults are installed strategically along the path of the conduit and cable. Many cables and conduits may terminate or run through these vaults or other similar compartments. When a conduit terminates, but the cable continues its run, it is desirable to provide a seal between the cable and the conduit at the termination of the conduit. 
         [0004]    A technical problem solved with the present invention is that fiber and/or copper cables need to enter an environmentally protected electronics enclosure. Their entry point must not compromise the environmental seal. The main issues are typically protection from Wind Driven Rain (WDR—hurricane type) and insects. 
         [0005]    There are a number of solutions; however, none that meet all needs. For example:
       One type is the rubber grommet. It typically is made of a rubber membrane that needs to be sliced to allow cable passage. The membrane does seal the cable entry to some extent, but not well enough to keep tiny insects out or WDR that may ride up the cables. To insure a proper seal, users add a liquid sealant such as RTV/caulking to completely seal these grommets.   The more waterproof type only allows the cable to pass through. This does not work for cables that are pre-terminated/connectorized as are some in our case.       
 
         [0008]    A particular example of the art is described in U.S. Pat. No. 4,842,364. In this case, the seal is formed by a gasket and supporting structure. The gasket and its supports can slide axially over the cable and into the conduit. However, this is not the case if the end of the cable is not accessible. In this case the gasket and its supports must be split or halved in order to surround the cable. The device described requires intricate fabrication techniques that utilize split threaded devices used for producing compression force on a gasket, thus causing the gasket to expand. The threaded nut is made in two halves and must be assembled around the cable. During fabrication of this nut, significant effort must be given to the correct timing of the threads so that when assembled the mating halves will produce a continuous thread. Assembly of the split halves can be difficult. In this prior art, the majority of the assembly of the seal occurs at the installation site, in the confines of an underground vault, which is difficult because the pieces are small and intricate. If the threaded parts are made of plastic, the tooling to produce these parts is intricate, complicated, and expensive. The amount of compression of the gasket in this and possible other prior art is dependent on how tightly threaded members are torqued. Since this torque is generally uncontrolled in the field, large forces may be transmitted which may damage the conduit and/or cable. Conversely, if too little torque is applied, the gasket may not seal as intended. Further, some prior art device use metal fasteners as part of the scheme to compress a gasket. Metal may corrode after time. These designs are optimized for water submersion and sealing individual cables. They do not seal well around more than one cable due to the required durometer of the gasket. In addition, the structure of the mechanism has to fit within the conduit severely restricting the size opening available for cable or cable with connector. 
         [0009]    Accordingly, there remains a need for an improved device which can be easily installed around a fiber optic and/or copper cables before or after installation of the cables and can be as easily removed, and which has no corrodible components. Such a device limited tools to install and remove, and should be inexpensive, durable and efficient in sealing the cable from foreign substances. 
       SUMMARY OF THE INVENTION 
       [0010]    Accordingly, it is the object of this invention to provide a simple, cost effective means to seal the area around a cable and the conduit in which the cable resides. The advantages can include: (a) ease of installation, (b) low cost, (c) complete assembly ease prior to installation, (d) controlled force that is transmitted to the cable and conduit, (e) improved sealing between cable and conduit, (f) resistance to chemicals in its environment, and (g) inherent corrosion resistance. 
         [0011]    Still further objectives and advantages will become apparent from a consideration of the ensuing description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1A  shows a view of a cable entry seal device in an engaged position according to an embodiment of the present invention; 
           [0013]      FIG. 1B  shows a view of a cable entry seal device in an unengaged position according to an embodiment of the present invention; 
           [0014]      FIG. 2A  shows a view of a cable entry seal device in an engaged position according to another embodiment of the present invention; and 
           [0015]      FIG. 2B  shows a view of a cable entry seal device in an unengaged position according to another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Now referring to  FIGS. 1A-1B  of the drawings, a first embodiment of the present invention is schematically depicted therein. 
         [0017]    The seal assembly is a sandwich or squeeze box seal design that can be placed over a cable and snapped/connected together around it. A connected seal assembly is shown in  FIG. 1B . The two halves  11 ,  13  have some form of foam rubber or similar resilient material  12  that wraps around the cable(s), which pass through the nut  15  and between the halves  11 ,  13 , when compressed by the two halves  11 ,  13  coming together. The material is contained in each half  11 ,  13  and can be made from one or several layers and even pre-shaped if necessary. The closed unit  20  then fits into and seals a standard conduit opening/hole in a cabinet or enclosure and is fixed to the cabinet by the nut  15  and threading  21 . For an existing terminated cable, the nut currently applied around the cable is reused so that it is not required to disconnect the terminated cable. Standard size for the nut  15  and threading  21  is from the Approved American National Standard (ANSI) for electrical rigid conduit. This design lends itself to be used on any enclosure design that has standard conduit openings. Once tightened to the opening using a standard conduit fitting nut  15 , the unit  20  cannot be opened without loosening the nut  15 . This ensures less possibility for someone to tamper with the seal. 
         [0018]    Now referring more particularly to  FIG. 1A , the seal assembly  20  is shown in unassembled components. Each half of the assembly  11 ,  13  includes half of the standard threadings  17 ,  19  of the connected assembly thread  21  so when snapped/connected together a standard size nut can be screwed thereon. Each half  11 ,  13  can be made from plastic, metal, or any other ridged material. The two halves  11 ,  13  are held together by a snap assembly  14 ,  16 . One of the halves  11  includes a pair of flexible arms  14  connected on opposing sides of the half  11  and which extend therefrom. The other half  13  includes a pair of bosses  16  connected on opposing sides of half  13  and adapted for engagement with the flexible arms  14 . When the two halves are compressed together, the flexible arms  14  snap over the bosses  16 . Thereafter, the nut  15  can be screwed onto the combined threadings  17 ,  19 . 
         [0019]      FIGS. 2A-2B  illustrates another embodiment of the present invention.  FIG. 2B  shows a connected seal assembly  40  is shown in  FIG. 1B . The two halves  31 ,  33  have some form of foam rubber or similar resilient material  12  that wraps around the cable(s), which pass through the nut  15  and between the halves  31 ,  33 , when compressed by the two halves  31 ,  33  coming together. The material  12  is contained in each half  33 ,  33  and can be made from one or several layers and even pre-shaped if necessary. The closed unit  40  then fits into and seals a standard conduit opening/hole in a cabinet or enclosure and is fixed to the cabinet by the nut  15  and threading  21 . Again, the standard size for the nut  15  and threading  21  is from the Approved American National Standard (ANSI) for electrical rigid conduit. 
         [0020]    Now referring more particularly to  FIG. 2A , the seal assembly  40  is shown in unassembled components. In this embodiment, one half of the assembly  33  includes the full standard threading  21  wherein the standard size nut  15  can be screwed thereon. Each half  31 ,  33  can be made from plastic, metal, or any other ridged material. The two halves  11 ,  13  are held together by a snap assembly  34 ,  36 . One of the halves  31  includes a pair of jutted ends  34  extending from opposing sides walls of the half  31 . The other half  33  includes a pair of notched corners  36 , located on opposing sides of half  31  and further located on the further most end wall from the engaging other half  31 , for engagement with the jutted ends  34 . When the two halves are compressed together, jutted ends  34  snap into the notched corners  36 . Thereafter, the nut  15  can be screwed onto the combined threading  21 . 
         [0021]    The embodiments of the present invention can be differentiated from existing solutions in that it is a fast, very inexpensive way to get a watertight seal while still having the ability to use pre-terminated cables. 
         [0022]    Some available solutions are time consuming in that they require a liquid sealant which also makes re-entry messy where the present invention requires no liquid sealant. Many of these must be custom designed for the specific application. Prior styles do not allow pre-terminated, or bundled, cables and therefore are not an option where the present invention allows for pre-terminated or bundled cables. Others also require special bulkhead designs or split openings rather than standard conduit sized holes where the present invention is designed for a standard conduit opening. 
         [0023]    Various other modifications, changes, alterations and additions can be made in the improved assembly of the present invention. All such modifications, changes, alterations and additions as are within the scope of the appended claims form part of the present application.