Abstract:
An apparatus and method for connecting an end of a first fiber optic cable to an end of a second fiber optic cable, the apparatus comprising a first fiber optic cable comprising at least one plastic fiber, a second fiber optic cable comprising at least one plastic fiber, a first fitting have a cavity for securing the end of said first fiber optic cable, a second fitting for securing the end of said second fiber optic cable, and a connector for joining the first fitting to the second fitting to hold the end of the first fiber optic cable in alignment with the end of the second fiber optic cable to allow light to pass therebetween.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to fiber optic cables and more specifically, to a coupling apparatus and method for connecting one or more fiber optic cables to a second fiber optic cable. 
     An optical fiber is an elongated glass or plastic filament, or fiber or strand, having a core region surrounded by one or more layers of cladding, with the core having a higher index of refraction than the cladding so that light introduced at one end of the fiber will be internally reflected for transmission longitudinally within the core channel to the other end of the fiber. A fiber optic cable comprises a sheath surrounding a multiplicity of optical fibers. The size of the fiber optic cable may vary widely depending on the number and size of the optical fibers within the sheath. 
     Typically, one end of the fiber optic cable is coupled to a light source to receive light energy, and the other end is positioned to emit the received light energy in an area to be illuminated. In another application, light is emitted from one or a plurality of sides of the fiber optic cable. Because fiber optic cables are often used to illuminate outdoor areas, the cables are exposed to the elements since the cables are either left laying above the ground or are buried underground. Either because of the elements, or because of damage unintentionally inflicted upon the cable, such as inadvertently striking the cable with a shovel, a fiber optic cable may become damaged to the extent that the sheath is pierced and the individual strands are severed. 
     Currently, when a cable is damaged, the complete cable must be replaced. Sometimes, because of the complexity involved in laying the original cable, the cost to replace the damaged cable can be expensive, even more than the original cost. For example, if part of a cable is buried underneath a decking surface adjacent to a pool, replacing the damaged cable may involve removing and replacing the decking surface. 
     SUMMARY OF THE INVENTION 
     In view of the prior history, users of fiber optic cables would benefit from a coupling or splicing apparatus where a damaged part of a cable can be removed and the resulting ends spliced together. Although there is a loss of light energy through a splice, the amount of energy passing is sufficient for many lighting applications and the cost to splice the cable is less than replacing the cable. In view of this need, an apparatus is providing for connecting an end of a first fiber optic cable to an end of a second fiber optic cable is needed. The apparatus comprises a first fiber optic cable comprising at least one plastic fiber, a second fiber optic cable comprising at least one plastic fiber, a first fitting have a cavity for securing the end of the first fiber optic cable, a second fitting for securing the end of the second fiber optic cable, and a connector for joining the first fitting to the second fitting to hold the end of the first fiber optic cable in alignment with the end of the second fiber optic cable to allow light to pass therebetween. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features and advantages of the present invention will become apparent from the following detailed description of the invention when read with the accompanying drawings in which: 
     FIG. 1 is an exemplary embodiment of the present invention separated to illustrate each part; 
     FIG. 2 is an exemplary embodiment of the present invention where a first part and second part for receiving a cable are formed but not connected to the other; 
     FIG. 3 is an embodiment of the present invention as illustrated in FIG. 2 with a cable inserted in each part; and 
     FIG. 4 is an embodiment of the present invention fully connected. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Before describing in detail various aspects of the present invention, it should be observed that the present invention broadly comprises a novel combination of components configured to quickly and reliably meet the repair needs when a fiber optic cable or strand is damaged or severed. Accordingly, these components have been represented by components in the drawings, showing only those specfic details that are pertinent to the present invention, so as not to obscure the disclosre with structural details or operational interrelationships that will be readily apparent to those skilled in the art having the benefit of the description herein. With reference to the drawings, exemplary embodiments of the invention will now be described. 
     As illustrated in FIG. 1, the present invention offers an apparatus for connecting ends of a fiber optic cable together or for connecting a respective end from a first fiber optic cable to a respective end from a second fiber optic cable. In particular, FIG. 1 is an exemplary illustration of the components needed, separated into individual elements, but when completely connected form the apparatus. The first set of components, or first fitting,  10  includes a first strain relief  16 . In a preferred embodiment, the strain relief  16  has an opening through its center that extends the length of the strain relief  16 , forming a chamber. The opening is cylindrical in shape with a smaller diameter at a first end  24  and a larger diameter at a second end  26 . In a preferred embodiment, an outer surface of the second end  26  of the strain relief  16  is threaded to fit within an adapter  18 . Approximately midway between the first end and the second end of the strain relief  16 , a stopper element  20  is located on the outside surface of the strain relief  16 . As illustrated in FIGS. 3 and 4, the stopper element  20  defines a distance the adapter  18  will fit on the strain relief when the apparatus  5  is assembled. 
     In another preferred embodiment, the strain relief  16  comprises two parts. The strain relief  16  has a cap  22  that is removable from a basic stem  23 . The cap  22  may be attached to the stem  23  with mechanical connection such as a threaded connection or a snap connection. The stem  23 , which receives the cap  22  is segmented (not shown) so that when the cap  22  is connected to the stem, the tightening of the cap  22  onto the stem  23  causes the opening in the stem to be reduced in diameter. Thus, when a cable  30  is in place, as illustrated in FIGS. 3 and 4, the reduced opening at the first end  24  assists in securing the cable  30  in place. 
     An insert  28  fits within, or engages, the second end  26  of the strain relief  16 . The insert  28  has an opening that extends from a first end  32  to a second end  34  of the insert  28 . In a preferred embodiment, the opening at the first end  32  of the insert  28  has a funnel-like shape. The outer surface of the second end  34  has a stopper, or stopper device,  36  that defines a distance the insert will fit within the strain relief  16 . 
     The adapter  18  has a chamber that extends from a first end to a second end. Though not necessary, in a preferred embodiment, the diameter  40  of the chamber is constant from the first end to the second end. The interior wall  40  of the chamber is threaded to receive the threaded outer surface of the strain relief  16 . Thus, when connected as illustrated in FIG. 2, the insert  16  is secured within the strain  16  relief, and the strain relief  16  and adapter  18  are mated together by way of each component&#39;s respective threads. In another embodiment, neither the strain relief  16  nor adapter  18  have threads. Instead, the mated surfaces are smooth and glue or some other mechanical connection, such as a detent, is used to connect the pieces. 
     As further illustrated in FIG. 1, the second set of components, or second fitting,  12  includes a second strain relief  70 . As previously discussed, the second strain relief  70  can be one or two pieces. In a preferred embodiment, the first and second strain reliefs  16 ,  70  are identical, but there is no requirement for the first strain relief  16  to be identical to the second strain relief  70 . The second set of components, or second fitting,  12  includes a second insert  72  that fits within, or engages, the second end  74  of the second strain relief  70 . A clamp nut  42  fits over the second end  74  of the second strain relief  70 . The clamp nut  42  has an opening in its center, forming a chamber, where a first end  52 , closest to the strain relief  70 , is a smaller diameter than a second end  54 . The smaller opening at the first end forms a lip  75  on the inside of the chamber. A flange  44  fits within the clamp nut  42 . The flange  44  has a chamber formed through its center that extends from a first end  46  to a second end  48 . A stopper  50  is located on the outer surface of the second end  48 . On a base  56  of the stopper  50  on the flange  44  is a groove, or channel  58 . An O-ring  60  fits within the groove. In a preferred embodiment, the inner surface of the opening in the flange  44  is threaded to accept the threaded outer surface of the second strain relief  70 . A stopper device  80  on the outer surface of the second strain relief  70  defines a distance for connecting the flange  44  to the strain relief  70 . When the flange  44  is placed through the first end  52  of the clamp nut  42  and is then connected to the strain relief  70 , the stopper  80  on the flange  44  connects to the lip  75  on the inside of the clamp nut&#39;s chamber. 
     As illustrated in FIG. 4, the adapter  18  fits within the second end  54  of the clamp nut  42 , forming a connector  82 . In a preferred embodiment, the outer surface of the adapter  18  is threaded and is received within the second opening  54  of the clamp nut  42 , which is also threaded to receive the adapter  18 . In another preferred embodiment, the mated surfaces are smooth and glue or some other mechanical connection, such as a detent, is used to connect the pieces. 
     In another preferred embodiment (not shown), the first and second insert  28 ,  72  are segmented around the outer surface away from the stopper  34 ,  77 . When each insert  28 ,  72  is placed within its respective strain relief  16 ,  70 , the inner chamber at the first end  32 ,  78  decreases in diameter as the inserts  28 ,  72  are placed further into its respective strain relief  16 ,  70 . Thus, when either an individual strand  60 , a plurality of individual strands  60  from a fiber optic cable or a fiber optic cable  30  are placed within the inserts  28 ,  72 , the cable  30  or strands  60  are held in place once the diameter of the insert  28  is narrowed by its insertion into the strain relief  16 . Thus, as illustrated in FIGS. 3 and 4, either a fiber optic cable  30 , individual strands  60 , or a combination of a cable  30  and individual strands  60  can be spliced with the present invention. 
     In operation, once a cable  30  or strands  60  are damaged or severed, a user will cut out the damaged segment where the remaining ends are smooth and the cable ends have a flat planar surface, as illustrated in FIG.  3 . The ends may be cut either before placing the cable  30 , or strands  60 , in each respective fitting or after the cables are secured within each respective fitting  10 ,  12  or after the cables  30  or strands  60  are secured within each respective fitting  10 ,  12 . The cables may be cut with a hot knife  85  or another apparatus capable of producing a smooth planar cut of a fiber optic cable  30  or strands  60 . The cables should be cut so that the respective ends will be able to be secured flush with the other cable end when secured within the apparatus. 
     In general, a first fiber optic cable  30 , or strands  60 , are inserted in a first end of a first fitting  10 . The fiber optic cable  30  or strands  60  are secured in the first fitting  10  so that the ends of the fiber optic cable extending from a second end  83  of the first fitting  10  are flush with the end of the fitting  10 . Once both fittings  10 ,  12  have a fiber optic cable  30  or strands  60  secured, the fittings  10 ,  12  are connected together so that the respective ends of each fiber optic cable make contact. The ends of the fiber optic cables  30  that will eventually be connected to the other cable may be cut either prior to securing the cables in each respective fitting or after the cables are secured. 
     In more detail, the first cable  30 , or strands  60 , are inserted into the first strain relief  16  and into the first insert  28  until the end of the first cable  30  or strands  60  are flush with the second end of the insert  28 . The insert  28  is then fixed within the first strain relief  16 . The same procedure is followed for placing the second cable  30  or strands  60  within the second strain relief  70  and the second insert  72 . The adapter  18  is then connected to the first strain relief  16 , either using each component&#39;s respective threads, or by another connecting method discussed previously. The clamp nut  42  is placed over the second strain relief  70 . The flange  44  is then connected to the second strain relief  70 , either using each component&#39;s respective threads, or by another connecting method discussed previously. The O-ring  60  is fixed within the base  56  of the flange  44 . The adapter  18  is then connected to the clamp nut  42 , either by each component&#39;s respective threads, or using another connecting method discussed previously. As the adapter  18  connects with the clamp nut  42 , the O-ring  60  contacts the adapter  18  and creates a seal, preventing light energy from escaping from the apparatus  5  at the point the ends of the cable  30 , or stands  60 , are coupled together. 
     While the invention has been described in what is presently considered to be a preferred embodiment, many variations and modifications will become apparent to those skilled in the art. Accordingly, it is intended that the invention not be limited to the specific illustrative embodiment but be interpreted within the full spirit and scope of the appended claims.