Patent Publication Number: US-2004046385-A1

Title: Low profile junction box connector

Description:
FIELD OF THE INVENTION  
       [0001] The invention relates to a connector that interconnects a conduit containing electrical cables and wires to an electrical junction box. In particular, an improved connector that is easy to attach to an electrical junction box, has a low profile and allows ease in fastening and ease in mass manufacturing at a low cost.  
       BACKGROUND OF THE INVENTION  
       [0002] An electrical junction box provides an interface for electrical cables from a central power distribution center to customers throughout a building served by the junction box. Numerous cables and wires contained in a generally cylindrical conduit enter and exit a junction box through openings on the walls of the junction box.  
       [0003] Connectors are used to properly and fixedly position and connect a conduit containing cables and wires to the junction box in order to establish electrical contact between the terminals of various wires running through one or more conduits in the junction box. It is therefore essential that not only the conduit connector or connectors terminate in the junction box but that measures be taken to prevent axial pullout or dislocation of the connector from the junction box which will place a strain on the electrical connections between various conductors carried by the conduits. Further, since a large number of cables and wires are usually crammed into an electrical junction box that, it is essential that a connector has a low profile to conserve space within the junction box and is easy to attach to the junction box to facilitate the handling of the numerous cables and wires.  
       [0004] U.S. Pat. No. 5,165,735 issued on Nov. 24, 1992 to Pierre Nardi et al. describes a prior art connector which typically includes a cylindrical body which is attached to the junction box by inserting the externally threaded end of the tubular body through an opening of the junction box, which is then secured with a locknut. A conduit is secured to the opposite end of the tubular body with a clamp, screw and washer. Another similar prior art connector is shown in U.S. Pat. No. 3,333,501 issued on Aug. 1, 1967 to H. H. Pitcher. These prior art connectors contain multiple parts, are complicated to manufacture and assemble, difficult to use and have a high profile that may interfere with the cables and wires contained in the junction box. Also, since the majority of these prior art connectors are molded, they are susceptible to breakage, if receiving any blow.  
       [0005] Therefore, there is a need for a connector that is easy to attach to an electrical junction box, strong, has a low profile and allows ease in fastening and ease in mass manufacturing at a low cost.  
       SUMMARY OF THE INVENTION  
       [0006] The present invention provides a junction box connector having minimal parts that are easy to assemble and manufacture at a low cost and has a low profile when attached to a junction box.  
       [0007] The connector of the present invention comprises a tubular casing having a front and end sections of enlarged and reduced diameters, respectively, and a locknut that cooperatively mates with the enlarged section of the tubular casing. The enlarged end of the tubular casing is internally threaded to receive the locknut. The reduced section of the tubular casing is adapted to receive a wire carrying conduit. An internally threaded, radially positioned, opening at the end section of the tubular casing is adapted to accept a set screw for securing the wire carrying conduit received in the tubular casing. The locknut comprises a tubular body having a front and end sections, with a curved flange at the front section and an externally threaded end section which cooperatively mates with the enlarged section of the tubular casing. The end section of the locknut has an internally extending rim that is adapted to abut the wire carrying conduit received in the tubular casing.  
       [0008] With the front section of the tubular casing abutting one side of an opening on the junction box, the locknut is inserted through the opening from the opposite side of the opening to engagingly mate with the front section of the tubular casing. Thereby, sandwiching the wall of the junction box between the flange of the locknut and the front section of the tubular casing for securely attaching the connector to the junction with a low profile.  
       [0009] The tubular casing and locknut of the present invention are preferably stamped, extruded or molded for ease of manufacturing at a low cost. Further, the connector of the present invention being a one piece steel extrusion, is strong and can be subject to severe abuse with no effect. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0010] A preferred embodiment of the present invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings forming a part of the specification wherein:  
     [0011]FIG. 1 is a cross sectional view of the connector of the present invention.  
     [0012]FIG. 2 is a cross sectional view of the tubular casing of the present invention.  
     [0013]FIG. 3 is a side view taken from line  3 - 3  in FIG. 2.  
     [0014]FIG. 4 is a cross sectional view of the locknut of the present invention.  
     [0015]FIG. 5 is a side view taken from line  5 - 5  in FIG. 4.  
     [0016]FIG. 6 is a top view taken from line  6 - 6  in FIG. 5 illustrating the bend comers of each tooth of the locknut. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0017] With reference to the drawings, wherein the same reference number indicates the same element throughout, there is shown in FIG. 1 a cross sectional view of the connector  10  of the present invention attaching a wire carrying conduit  12  to an opening  14  on a wall  16  of a junction box  18 . As shown in FIG. 1, the connector  10  includes a tubular casing  20 , a locknut  30  and a set screw  40 .  
     [0018] As shown in FIGS. 2 and 3, the tubular casing  20  has a front section  22  with an enlarged diameter and an end section  24  with a slightly reduced diameter. The internal diameter of the end section  24  is sized to receive a corresponding wire carrying conduit  12  of a predetermined diameter (as shown in FIG. 1). The front section  22  is internally threaded to receive locknut  40  (as shown in FIG. 1). At the end section  24 , an internally threaded, radially positioned, opening  26  is provided to receive a set screw  40  for securing the conduit  12  (as shown in FIG. 1).  
     [0019] As shown in FIGS. 4 and 5, the locknut  30  has a tubular body with a front section  32  and an end section  34 . Extending radially from the front section  32  is a flange  36  comprising a plurality of teeth  38 . The flange  36  is slightly curved towards the end section  34 . The end section  34  is externally threaded which cooperatively mates with the internal threading of the enlarged front section  22  of the tubular casing  20  (as shown in FIG. 1). A rim  40  extends radially inward from the end section  34 . Rim  40  is adapted to abut the conduit  12  received in tubular casing  20  and is dimensioned to be slightly smaller that the predetermined diameter of the conduit  12  (as shown in FIG. 1) to prevent the conduit  12  from protruding into the junction box  18 .  
     [0020]FIG. 6 illustrates that each teeth  38  of the flange  36  has a bend corner that improves the handling of the locknut  30  when securing the locknut  30  to the tubing casing  20 .  
     [0021] As shown in FIG. 1, when the connector  10  is in use, the front section  22  of the tubular casing  20  is positioned adjacent the opening  14  on one side of the wall  16  of the junction box  18 , and the end section  34  of the locknut  30  is inserted through the opening  14  from the opposite side of the wall  16  to threadedly mate with the front section  22  of the tubular casing  20 . Thereby, sandwiching the wall  16  between the tubular casing  20  and the locknut  30  to secure the connector  10  to the junction box  18 . With the locknut  30  being threaded into the tubular casing  20 , the connector  10  has a low profile that converse space within the junction box  18 . The curved flange  36  advantageously provides improved contacts between the locknut  30  and the wall  16  of the junction box  18 . To interconnect a conduit  12  with the junction box  18 , the conduit  12  is inserted into the tubular casing  20  from the end section  24  until it abuts the rim  40  of the locknut  30 . The set screw  40  may be tightened to securely attached the conduit  12  within the tubular casing  20 .  
     [0022]FIGS. 7 and 8 illustrate an alternate locknut  30 ′ similar to the locknut  30  of FIGS. 4 and 5 with a slightly curved flange  36 ′ that radially extends from the front section  32 .  
     [0023] In view of the simple structure of the tubular casing  20  and lock nut  40 , the connector  10  of the present invention may be advantageously stamped or extruded from a tubular shaped material or molded. Thereby, substantially lowering the cost of manufacture.  
     [0024] The features of the invention illustrated and described herein is the preferred embodiment. Therefore, it is understood that the appended claims are intended to cover unforeseeable embodiments with insubstantial differences that are within the spirit of the claims.