Abstract:
A cold-shrink article having a chamber with an enlarged interior section to prevent the collapse of an end of a support core placed in the chamber.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to U.S. Provisional Patent Application 61/174,632, filed May 1, 2009. 
    
    
     TECHNICAL FIELD 
     This invention relates to a cold-shrink cable termination system. 
     BACKGROUND 
     A cable termination system typically includes a cable terminated with a metallic lug (i.e., cable connector), the cable connector and end portion of the cable being inserted into the housing of a connecting device, the cable connector being connected to a mating device within the confines of the housing. The housing needs to form a tight seal around the end portion of the cable to prevent contamination or corrosion of the connection. 
     A problem that arises with cable termination systems is that the internal diameter of the housing has to be adapted to the diameter of the cable. Cable sizes vary so it&#39;s necessary to have either several connecting devices of different sizes, each being designed to fit exactly the diameter of the particular cable, or several adapters of different thicknesses, each adapter enabling the housing to be adapted to a cable of a given diameter. These solutions are costly because they require a large number of connecting devices or adapters to adapt to a whole range of cables. 
     Another known solution is to provide a cold-shrink housing that can be expanded over almost its entire length to receive cables having a range of diameters. When a cold-shrink housing is used, a removable support core is placed within a portion of the housing. The removable support core has an outer diameter that is larger than the inner diameter of the housing portion when it is in a relaxed state. The removable support core holds the housing in an expanded state until the cable end and lug are inserted into the housing. The core is then removed, allowing the cold shrink housing to tighten around the cable. 
     A problem with the cold-shrink cable termination system is that the end of the removable support core placed within the housing cannot withstand the excessive pressure placed upon them by the expanded housing and will often collapse. Prior art references have sought to address this problem by reinforcing the ends of the removable support core. 
     SUMMARY 
     The present invention seeks to address the issue of core collapse caused by the excessive pressure of an expanded housing. However, unlike prior art solutions, the present invention focuses on the housing rather than the core. 
     The present invention features a novel article comprising a cold-shrink housing having a first chamber that intersects with a second chamber, the first chamber having a generally cylindrical shape with an upper portion nearest the second chamber, the upper portion having a diameter greater than the diameter of the remainder of the first chamber. 
     An advantage of at least one embodiment of the present invention is that it reduces the amount of pressure exerted on an end of a cold-shrink support core inserted furthest into a connecting device housing, thereby reducing the likelihood of core collapse. 
     Another advantage of at least one embodiment of the present invention is that the semi-conductive layer on the interior of the first chamber of the connecting device makes intimate contact with the cable connector. 
     An advantage of at least one embodiment of the present invention is that the outer semi-conductive layer provides an integrated ground because it makes contact with the cable metallic ground layer. 
     An advantage of at least one embodiment of the present invention is that the cold-shrink connecting device eliminates the need for a cable adapter. This eliminates an electrical interface, which can fail. 
     The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The Figures and detailed description that follow below more particularly exemplify illustrative embodiments. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  depicts a typical cable assembly suitable for use with the present invention. 
         FIG. 2  depicts an embodiment of the connecting device of the present invention. 
         FIG. 3  depicts an embodiment of the connecting device of the present invention with a removable support core loaded in the connecting device. 
         FIG. 4  depicts an embodiment of the connecting device of the present invention with a cable assembly in the connecting device. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof. The accompanying drawings show, by way of illustration, specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized, and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the invention is defined by the appended claims. 
       FIG. 1  shows a standard power cable assembly  20  which includes cable connector  22  attached to a cable  24 . Cable  24  includes cable conductor  26  concentrically surrounded by cable insulation  28 , cable insulation shield  30 , cable metallic ground  32 , and cable jacket  34 . To form cable assembly  20 , each of the cable insulation  28 , cable insulation shield  30 , cable metallic ground  32 , and cable jacket  34  are stripped back from and end of cable  24  to expose a portion of the underlying layer, down to cable conductor  26 . Cable connector  22  is then attached to the exposed portion of cable conductor  26  by any suitable means, typically by crimping. 
       FIG. 2  shows connecting device  100  which includes housing  102  that generally defines first chamber  104  and second chamber  106 . First chamber  104  and second chamber  106  intersect such that the interior of first chamber  104  is in communication with the interior of second chamber  106 . First and second chambers  104 , 106  may intersect to form a general T-shape as shown in  FIG. 2  or a general L-shape (not shown). First chamber  104  further includes an upper portion  108  located nearest to second chamber  106 . As can be seen in  FIG. 2 , the inner and outer diameter of upper portion  108  of chamber  104  are larger than the inner and outer diameters of the remainder of first chamber  104 . Housing  102  may further include an outer semi-conductive layer  110  and an intermediate insulating layer  112 , with the interior wall of first chamber  104  being at least partially covered by inner semi-conductive layer  114 . 
     Housing  102  may be made from any material suitable for cold-shrink applications. Most suitable are materials such as a highly elastic rubber material that has a low permanent set, such as ethylene propylene diene monomer (EPDM), elastomeric silicone, or a hybrid thereof. The semi-conductive and insulating materials may be made of the same or different types of materials. The semi-conductive and insulating materials may have differing degrees of conductivity and insulation based on the inherent properties of the materials used or based on additives added to the materials. 
     To enable cable assembly  20  to be inserted into first chamber  104  of connecting device  100 , a removable support support core  200  is first loaded into first chamber  104 , as illustrated in  FIG. 3 . Once loaded, removable support support core  200  typically extends from the end of the upper portion  108  nearest the second chamber  106  to beyond the open end  109  of first chamber  104  through which cable assembly  20  is inserted. When loaded into first chamber  104 , removable support support core  200  radially expands first chamber  104  to an inner diameter greater than the outer diameter of the largest portion of cable assembly  20  that will be inserted into first chamber  104 . 
     Removable support support core  200  may be made of any suitable material and in any suitable configuration, but typically consists of an extruded nylon or propylene ribbon that is helically wound. To remove removable support support core  200  from first chamber  104 , removable support support core is unraveled by pulling on a tab (not shown) extending from one end of the removable support support core  200  and causing separation of the core along the helical score line. Preferably, removable support core  200  is unraveled starting with the end in upper portion  108  nearest the second chamber  106  and ending with the end that extends beyond the open end  109  of first chamber  104 . Unraveling removable support support core  200  in this manner prevent the open end  109  of first chamber  104  from prematurely collapsing and obstructing the removal of removable support support core  200 . 
     When an end of a removable support support core is located in the interior of a chamber as in the present invention, it is possible that the pressure exerted by the expanded chamber on the end of the core in the chamber will cause the end of the removable support support core to collapse. The present invention addresses this issue by providing an upper portion  108  of the first chamber that has a larger inner and outer diameter than the remainder of the chamber. With this feature, the upper portion  108  of the first chamber is required to expand less than in a prior art connector devices not having this feature, and therefore, less pressure is exerted upon the end of the removable support core in the interior of the chamber, compared to similar prior art connector devices. 
     Preferably the inner diameter of the upper portion  108  of first chamber  104  is of a size in comparison to the outer diameter of a removable support core  200  inserted into first chamber  104  such that the maximum increase in the inner diameter of the upper portion  108  when removable support core  200  is loaded within first chamber  104  is less than 100%, and more preferably equal to or less than about 20% and greater than 0%, of the inner diameter absent removable support core  200  in first chamber  104 . 
     The difference in inner diameter of the upper portion  108  and remainder of first chamber  104  will typically cause the upper portion  108  and the remainder of the first chamber to experience a differential increase in inner diameter when a removable support core is loaded into the first chamber. In other words, the inner diameter of the upper portion  108  will be required to increase less than the inner diameter of the remainder of the first chamber to accommodate a removable support core  200 . This is particularly true when the removable support core  200  has a constant outer diameter, but may also be true when the removable support core has a tapered or stepped shape. Regardless of the shape of the removable support core  200 , it is desirable that the outer diameter of the removable support core  200  is larger than the inner diameters of both the upper portion and the remainder of the first chamber in its relaxed state so that inner surface of the first chamber  104  exerts at least a sufficient amount of pressure on the removable support core  200  to keep it from dislodging from the first chamber  104 . If the outer diameter of the removable support core  200  varies along its length, as with a tapered or stepped core, preferably the outer diameter of each portion of the removable support core  200  is greater than the inner diameter of the adjacent portion of the first chamber  104 . 
     Preferably, the maximum increase in the inner diameter of the upper portion when a removable support core is loaded within the first chamber is between about 100% and about, but greater than, 0% of the inner diameter absent the removable support core in the first chamber and the maximum increase in the inner diameter of the remainder of the first chamber when a removable support core is loaded within the first chamber is between about 150% and about 300% of the inner diameter absent the removable support core in the first chamber. 
     Once the removable support core has been loaded into the first chamber  104 , cable assembly  20  may be inserted into first chamber  104 . Typically, cable connector  22  will include an aperture  23  at its free end. The free end is positioned in the intersection of the first and second chambers,  104 ,  106  with the remainder of the cable connector residing in the upper portion, and an adjacent portion of chamber, of first chamber  104 . Once the cable assembly is correctly positioned, a stud (not shown) may be inserted through aperture  23  and one or more mating devices  42  may be inserted into second chamber  106  and attached to, or held in position against, cable connector  22  by the stud. Removable support core  200  may then be removed as described above to cause first chamber  104  to contract and form a tight seal around cable assembly  20 . 
     As shown in  FIG. 4 , when the connecting device has been fully assembled, the inner semi-conducting layer  114  on the interior wall of the first chamber  104  of the housing  102  makes intimate contact with the cable connector  22  of cable assembly  20 . Preferably, the inner semi-conducting layer  114  also makes intimate contact with the cable insulation  28  of cable assembly  20 . A portion of the interior wall of first chamber  104  is made of the intermediate insulating layer  112 . This portion preferably makes intimate contact with cable insulation  28 . A portion of the interior wall of first chamber  104  is made of outer semi-conducting layer  110 . This portion preferably makes intimate contact with cable insulation shield  30 , and typically also makes intimate contact with cable metallic ground  32 , which may be a tape or wire layer. The portion of the interior wall of first chamber  104  made of the outer semi-conducting layer  110  preferably also makes intimate contact with a portion of cable jacket  34  to prevent contaminants and/or moisture from entering the first chamber  104 . 
     Although specific embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the preferred embodiments discussed herein. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof