Patent Abstract:
A separable, flexible connection arrangement is provided for connection of two conductors. In one arrangement, the separable, flexible connection arrangement is utilized to provide an externally removable bushing for connecting an electrical component located within a sealed enclosure.

Full Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 60/418,083 filed on Oct. 11, 2002. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates generally to flexible connections and more particularly to an externally removable bushing that provides a flexible connection to components located within a switchgear.  
           [0004]    2. Description of the Related Art  
           [0005]    Switchgear for electrical power distribution systems commonly include enclosures defining contained environment desirable for circuit-interrupting functions of the enclosed components. In order to connect the enclosed components to external power cables, a bushing is utilized to provide a conductor through the sealed enclosure of the switchgear and to insulate the conductor from the enclosure. The bushing typically includes provisions for assembly with separable connectors which interface between the bushing and the power cables. The external portions of the bushing are subject to damage which may render the bushing unusable, requiring replacement of the bushing. This requires disconnection of the bushing from the enclosed components. If this disconnection of the bushing requires opening of the enclosure, the replacement of the bushing is not only time-consuming and difficult to perform in confined spaces, the design of the switchgear enclosure is also complicated thereby since opening features must be incorporated.  
           [0006]    U.S. Pat. Nos. 4,767,351 and 5,904,577 illustrate arrangements that provide an externally-separable bushing such that connection and disconnection to enclosed components may be accomplished external to the enclosure and not requiring opening of the enclosure. In U.S. Pat. No. 4,767,351, the conductor of that bushing arrangement includes a cylindrical rod which is permanently and rigidly attached to the enclosed component and a sleeve with annular passage that receives the rod. The bushing also includes provisions for threadably connecting the two conductor parts. Thus, the bushing is removed by unthreading of the bushing from the cylindrical conductor such that the remainder of the bushing may be removed. This arrangement also requires provisions for sealing the junction of the two conductor parts.  
           [0007]    While the prior art arrangements may be useful to provide connections to enclosed electrical components, it is always desirable to provide simplified manufacture and structure.  
         SUMMARY OF THE INVENTION  
         [0008]    Accordingly, it is a principal object of the present invention to provide an externally removable bushing connector that provides connection to an electrical component located within a switchgear enclosure while providing ease of use and a flexible connection to the electrical component.  
           [0009]    These and other objects of the present invention are efficiently achieved by the provision of a separable, flexible connection arrangement for two conductors. In one arrangement, the separable, flexible connection arrangement is utilized to provide an externally removable bushing for connecting an electrical component located within a sealed enclosure. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0010]    The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the specification taken in conjunction with the accompanying drawing in which:  
         [0011]    [0011]FIG. 1 is a perspective view of the connection arrangement of the present invention;  
         [0012]    [0012]FIG. 2 is a top plan view of FIG. 1 and including a switch blade assembly;  
         [0013]    [0013]FIG. 3 is a partial, sectional view taken generally from the line  3 - 3  of FIG. 2;  
         [0014]    [0014]FIG. 4 is a perspective view of a switch blade assembly to which connection is made by the present invention; and  
         [0015]    [0015]FIGS. 5 and 6 are respective front and right-side elevational views of a contact plate of the connection arrangement of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0016]    Referring now to FIGS.  1 - 6 , the connection arrangement  10  of the present invention provides a separable, flexible electrical connection between two conductors  12 ,  14 . In a specific illustration as shown in FIGS. 1 and 2, the conductor  12  of the connection arrangement  10  is the conductor of a bushing  16  that is externally removable with respect to a wall  18  of an enclosure  19  (FIG. 2). The conductor  14  provides electrical connection to an electrical component (not shown) housed in the enclosure  19 . The bushing  16  is removable from the wall  18  via a fastening arrangement, e.g. fasteners  15  that are carried by the wall  18  and pass through apertures  17  in the bushing  16 . Thus, when the bushing  16  is unfastened from the wall  18 , the bushing  16  may be disconnected from the conductor  14  and removed for replacement etc. The connection arrangement  10  is movable along the direction  60  for connection to and disconnection from the conductor  14 .  
         [0017]    The connection arrangement  10  includes a contact arrangement  20  that makes electrical connection with the conductor  12  and includes a separable contact  22  that is arranged for separable connection with the conductor  14 . In the illustrative example, the conductor  14  is a central hub portion of an overall switch blade assembly  24  that is carried on and rotates with an operating strut or shaft  26  about an axis  27  (FIG. 4). The separable contact  22  includes two parallel, opposed contact plates  28 ,  30  each of which including a y-shaped or yoke contact opening  32  along the leading edge thereof. The contact openings  32  interfit about the operating strut  26  while the plates  28 ,  30  engage the hub of the conductor  14  to provide the electrical connection thereof. As shown in FIG. 3, contact is made between the conductor  14  and the plates  28 ,  30  at protruding contact portions  34 ,  36  respectively provided at the upper and lower portions of the yoke contacts. In a preferred embodiment, the contact portions  34 ,  36  are elongated and tapered along an axial direction  60  of the bushing  16  while being generally curved in the direction transverse thereto as show in FIG. 6. The contact arrangement  20  includes generally spherical contact portions  40 ,  42  on the plates  28 ,  30  respectively to provide electrical connection with the conductor  12  at  43  via a slotted portion  44  of the conductor  12  and a rivet  46  that passes through apertures  41  in the spherical contact portions  40 ,  42 . The contact arrangement  20  also includes two spring members  48 ,  50  disposed on the outside of the plates  28 ,  30  respectively and a rivet  52  that passes through apertures  54  in the plates  28 ,  30  and apertures  56  in the spring members  48 ,  50 . The spring members are arranged to compress the spring members  48 ,  50  so as to provide a desired contact force, e.g. approximately  50  pounds. A spacer element  57  is provided about the rivet  52  and between the contact plates  28 ,  30 . Thus, the contact arrangement  20  is movable for rotation about the rivet  46 .  
         [0018]    In accordance with important aspects of the present invention, the connection arrangement  10  provides a stable connection arrangement with resilient and flexible characteristics to accommodate positional changes between the conductors  12  and  14  while maintaining desired electrical connection and contact pressure, and also permits the bushing  16  to be removed from the housing  19  without entering the interior of the enclosure  19  which is gas-filled in an illustrative embodiment. For example, the connection arrangement  10  prevents rotation of the contact plates  28 ,  30  away from the switch blade assembly  24  in the direction  58  via the engagement of the yoke portions around the operating strut  26 . Furthermore, the connection arrangement  10  is prevented from sliding away from the switch blade assembly  24  in the direction  60  via the mounting of the bushing  16  and the limited movement of the contact arrangement  20  in the direction  60 . Thus, the connection arrangement  10  provides separable, but definite orientation and stability.  
         [0019]    While there have been illustrated and described various embodiments of the present invention, it will be apparent that various changes and modifications will occur to those skilled in the art. Accordingly, it is intended in the appended claims to cover all such changes and modifications that fall within the true spirit and scope of the present invention.

Technology Classification (CPC): 7