Patent Publication Number: US-7915543-B2

Title: Isolator assembly, receptacle and method of operation

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electrical fittings and, more particularly, to electrical outlet boxes. 
     2. Description of the Related Art 
     Electrical power is distributed by networks of electrical conduits that terminate in electrical outlet boxes where the electrical power is accessed. Power from the electrical conduits is connected in the outlet boxes to electrical receptacles positioned on the boxes. The electrical receptacles have slots and apertures for receiving prongs of appliances and to connect to other electrical devices. Such networks are used in residential and commercial construction, as well as, in mobile structures such as trailers and motor homes. 
     Typically, the electrical conduits have a threaded stem that is fitted into an opening in an electrical outlet box. The stem is secured to the electrical outlet box by a threaded nut, for example, a Romex nut. Electrical wires within the electrical conduits are connected to the electrical receptacle by connectors within the electrical outlet box. 
     The threaded nut is located within the electrical outlet box and is accessed to secure the nut to the box by at least partially removing the electrical receptacle. After the electrical wires within the electrical conduits are connected to the electrical receptacle, the electrical receptacle is secured to the electrical outlet box. 
     The threaded nut may loosen with time, compromising the securement of the electrical receptacle to the electrical outlet box. Vibrations in environments, such as mobile structures, may hasten the loosening of the threaded nut. Further, the loosening of the threaded nut may progress until it comes off the stem and becomes loose within the electrical outlet box. The loose nut may contact wires or electrical connectors within the box. 
     What is needed in the art is an electrical box and receptacle assembly that is more reliable and secure. 
     SUMMARY OF THE INVENTION 
     The invention in one form is directed to an isolator assembly having an electrical receptacle housing. The housing defines an aperture extending inwardly from a first exterior wall of the housing and a longitudinal centerline of the aperture. The housing further has an internal cavity extending from the aperture and a slot spaced from the internal cavity and extending from a second exterior wall of the housing. The slot is generally perpendicular to the longitudinal centerline of the aperture. The isolator assembly also includes a plurality of terminals positioned in the housing, a nut sized for placement in the slot of the housing, a conduit fitting including a stem having a portion thereof sized for placement in the aperture of the housing and a flexible conduit. The conduit is connected to the conduit fitting and contains a plurality of electrical conductors connected to the plurality of terminals within the electrical receptacle housing. 
     The invention in another form is directed to a method for wiring an electrical receptacle. The method includes the step of providing an electrical receptacle housing. The housing has an aperture extending inwardly from a first exterior wall of the housing, an internal cavity extending from the aperture, and a slot. The slot is spaced from the internal cavity and extends from a second exterior wall of the housing. The method also includes the steps of providing a conduit fitting including a stem, providing a nut, placing the nut into the slot of the housing, inserting the stem into the aperture of the housing, and threading the nut onto the stem. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a side view of an embodiment of an isolator assembly of the present invention; 
         FIG. 2  is a bottom view of the electrical receptacle housing assembly of the isolator assembly of  FIG. 1 , showing the faceplate of the electrical receptacle housing assembly in greater detail; 
         FIG. 3  is a side view of the conduit fitting of the isolator assembly of  FIG. 1 , including the elbow clamp and the flexible conduit; 
         FIG. 4  is a plan view of the nut of the isolator assembly of  FIG. 1 ; 
         FIG. 5  is a side view of the electrical receptacle housing assembly of the isolator assembly of  FIG. 1 ; 
         FIG. 6  is a top view of the electrical receptacle housing assembly of the isolator assembly of  FIG. 1 , showing the hole in the top of the receptacle housing assembly; 
         FIG. 7  is a perspective view of the electrical receptacle housing assembly of the isolator assembly of  FIG. 1 , showing the slot for receiving the nut in greater detail; 
         FIG. 8  is a bottom view of the electrical receptacle clamp connection portion of the electrical receptacle housing assembly of the isolator assembly of  FIG. 1 , showing the surface for engagement with the electrical receptacle faceplate portion in greater detail; 
         FIG. 9  is a top view of the electrical receptacle faceplate portion of the electrical receptacle housing assembly of the isolator assembly of  FIG. 1 , showing the electrical conductor passages and the surface for engagement with the electrical receptacle clamp connection portion in greater detail; and 
         FIG. 10  is a flow diagram of a method for wiring an electrical receptacle, according to the present invention. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     According to the present invention and referring now to  FIG. 1 , an isolator assembly  10  is shown. The isolator assembly  10  includes an electrical receptacle housing  12 . A conduit fitting  14  connects a flexible conduit  16  to the electrical receptacle housing  12 . The isolator assembly  10  further includes a nut  18  placed in a slot  20  formed in the housing  12 . Electrical conductors  22  within the conduit  16  are connected to terminals  24  in the housing  12 . The electrical receptacle housing  12  defines an aperture  26  extending inwardly from a first exterior wall  28  of the housing  12 . The housing  12  defines a longitudinal centerline  30  of the aperture  26 . The housing  12  further defines an internal cavity  32  extending from the aperture  26 . The housing  12  also defines the slot  20  that is spaced from the internal cavity  32  and extends from a second exterior wall  36  of the housing  12 . The slot  20  is generally perpendicular to the longitudinal centerline  30  of the aperture  26 . The nut  18  is sized for placement in the slot  20  of the housing  12 . The conduit fitting  14  includes a stem  38  having a portion  40  of the stem  38  sized for placement in the aperture  26  of the housing  12 . 
     The slot  20  serves to keep the nut  18  from entering the internal cavity  32  of the electrical receptacle housing  12 . The nut  18  is trapped within the slot  20  and may not advance toward the internal cavity  32 . Thus, the slot  20  of the electrical receptacle housing  12  serves to mechanically and electrically isolate the nut  18  from the internal cavity  32  of the housing  12 . Thus, the nut  18 , if it becomes loose from the conduit fitting  14 , may not advance into the internal cavity  32  of the housing  12  and contact any of the plurality of terminals  24  or any of the plurality of electrical inductors  22 , therefore, assuring the safety of the isolator assembly  10 . 
     As shown in  FIG. 1 , the housing  12  includes a third wall  42  spaced from the first exterior wall  28  of the electrical receptacle housing  12 . The third wall  42  may, as shown, be parallel to the first exterior wall  28  of the electrical receptacle housing  12 . The slot  20  is positioned between the first exterior wall  28  and the second exterior wall  36 . The third wall  42  separates the slot  20  from the internal cavity  32  of the housing  12 . The aperture  26  extends inwardly from the third wall  42  and into the internal cavity  32 . The nut  18  is sized to prohibit passage of the nut  18  through the aperture  26  and into the internal cavity  32 . The nut  18  is further sized to permit rotation of the nut  18  within the slot  20 . 
     The slot  20  is a blind slot in that the slot  20  is partially formed by or terminates in a back wall  44  of the housing  12 . The slot  20  formed in the housing  12 , therefore, contains the nut  18  on three sides, facilitating the assembly of the nut  18  into the isolator assembly  10 . It should be appreciated, however, that the slot  20  may, alternatively, extend completely through the housing  12 . 
     As shown in  FIG. 1 , the housing  12  includes an electrical receptacle conduit connection portion or first portion  46  and a distal and an electrical receptacle faceplate portion or second portion  48 . The first portion  46  and the second portion  48  are removably secured to each other to form the housing  12 . The first portion  46  of the housing  12  defines the aperture  26  and the slot  20 , while the second portion  48  defines at least a portion of the internal cavity  32 . The internal cavity  32  is configured to receive at least a portion of the plurality of electrical conductors  22 . 
     The first portion  46  may be secured to the second portion  48  by, for example, fasteners  50  in the form of self-tapping screws. The conduit fitting  14  of the isolator assembly  10  of  FIG. 1  may, as shown, be in the form of an elbow clamp and may include external threads  52  formed on portion  40  of the stem  38  of the fitting  14 . The external threads  52  mate with internal threads  54  formed in the nut  18 . 
     The first portion  46  of the housing  12 , as shown in  FIG. 1 , includes internal face  56  of the first external wall  28 . The internal face  56  is perpendicular to longitudinal centerline  30  of the aperture  26 . The slot  20  is formed between the second exterior wall  36  and the internal face  56  of the first external wall  28 . As shown in  FIG. 1  the slot  20  receives the nut  18  and the nut  18  is used to secure the conduit fitting  14  against the internal face  56  of the first external wall  28  of the housing  12  and the first external wall  28  of the housing  12 . The electrical conductors  22  are fitted within flexible conduit  16  and pass through the conduit fitting  14  and the aperture  26 , extending into the internal cavity  32 . The electrical conductors  22  are connected to terminals  24  within the internal cavity  32 . 
     Referring now to  FIG. 2 , bottom face  58  of the second portion  48  of the housing  12  of isolator assembly  10  is shown. The bottom face  58  as shown is a faceplate in the form of an electrical duplex. The faceplate  58  includes a pair of grounding openings  60  as well as a pair of neutral slots  62  and a pair of hot slots  64 . One of the terminals  24  is associated with each of the grounding openings  60 , the neutral slots  62 , and the hot slots  64 . The faceplate  58  further includes a pair of opposed tabs  66  which extend from opposed arms  68  extending from the second portion  48  of the housing  12 . The tabs  66  are used to releasably secure the second portion  48  of the housing  12  from wall  70  of the living space at which the isolator assembly  10  is installed. While the faceplate  58  may be in the form of an electrical duplex, it should be appreciated that the faceplate  58  may be in the form of any electrical connection. For example, the faceplate  58  may be in the form of a light socket or a switch. 
     Referring now to  FIG. 3 , the conduit fitting  14  of the isolator assembly  10  is shown in greater detail. The conduit fitting  14  is secured to the flexible conduit  16  as well as to housing  12 . As shown, the conduit fitting  14  has a generally cylindrical cavity for receiving a generally cylindrical flexible conduit  16 . The conduit fitting  14 , as shown, includes an upper portion  72  and a lower portion  74  that are secured together by fasteners in the form of self-tapping screws  76 . The lower portion  74  includes the stem  38  having the external threads  52 . 
     Referring now to  FIG. 4 , the nut  18  is shown in greater detail. The nut  18  has cylindrical internal threads  54 , as well as a plurality of spaced-apart protrusions  78 . The protrusions  78  are used to tighten the nut  18  while it is fitted in the slot  20 . The nut  18  has six equally spaced apart protrusions  78 . Six protrusions  78  are sufficient to have at least one protrusion  78  in the open portion of the slot  20  at all times so that the nut  18  may be easily tightened and loosened. Alternatively, any other number of protrusions or any other feature on the nut may be provided to turn the nut. 
     It should be appreciated that the flexible conduit  16 , the conduit fitting  14 , and the nut  18  may be made of any suitable, durable material and may be made of electrically conductive material or an electrically insulative material. For example, the nut  18 , the conduit fitting  14 , and the flexible conduit  16  may be made of a suitable, durable metal. It should be appreciated that, alternatively, the conduit  16 , the conduit fitting  14  and the nut  18  may be made of a composite or of a polymer. 
     Referring now to  FIG. 5 , the first portion  46  and the second portion  48  of the housing  12  are shown connected to each other. The first portion  46  of the housing  12  defines the aperture  26  which includes a cylindrical opening or hole  80  through first external wall  28  of the housing  12  and a cylindrical hole or opening  82  through the third wall  42  of the first portion  46  of the housing  12 . 
     Referring now to  FIG. 6 , the first portion  46  of the housing  12  of the isolator assembly  10  is shown viewed from the top of the isolator assembly  10 . The first portion  46  includes openings  84  for receiving the fasteners  50  for securing the first portion  46  to the second portion  48 . 
     Referring now to  FIG. 7 , the slot  20  as shown is formed in the first portion  46  of the housing  12 . The slot  20  is defined and bounded by the internal face  56  of the first external wall  28 , second exterior wall  36 , third wall  42 , side walls  89 , and back wall  44  of the first portion  46  of the housing  12 . 
     Referring now to  FIG. 8 , the first portion  46  of the housing  12  of the isolator assembly  10  is shown viewed from the bottom. The first portion  46  includes a contact surface  86  for contact with the second portion  48 . The first portion  46  further includes a pair of transfer support ribs  88  for strengthening the first portion  46 . 
     Referring now to  FIG. 9 , the second portion  48  of the housing  12  of the isolator assembly  10  is shown with the second portion  48  including a plurality of pockets  90  for threadably receiving the screws  50  that are used to secure the first portion  46  of the housing  12  to the second portion  48  of the housing  12 . The second portion  48  includes a contact surface  91  of engaging contact surface  86  of the first portion  46 . 
     The second portion  48  of the housing  12  further includes a plurality of spaced-apart walls  92 . The plurality of spaced-apart walls  92  extend generally parallel to the longitudinal centerline  30  of the aperture  26 . The plurality of spaced-apart walls  92  form a plurality of spaced-apart passages  94  in the internal cavity  32  of the housing  12 . The plurality of spaced-apart passages  94  are configured to receive electrical conductors  22  and terminals  24 . The passages  94  are adapted to provide a location for the conductors  22  to be connected to the terminals  24 . 
     As shown in  FIG. 9 , a sufficient number of passages  94  are provided such that each terminal  24  may be electrically and mechanically isolated from each of the other terminals  24 . Similarly, the number of passages  94  may be sufficient such that only one electrical conductor  22  needs to be placed in a particular passage  94 . Therefore, the passages  94  serve to electrically isolate the electrical conductors  22  from each other and the terminals  24  from each other. It should be further appreciated that the spaced-apart walls  92  serve to further prohibit the passage of the nut  18  into the internal cavity  32  of the second portion  48  of the housing  12 . 
     The first portion  46  and the second portion  48  of the housing  12  may be made of any suitable, durable materials and may be made of electrically conductive materials or electrically insulative materials. Preferably, the first portion  46  and the second portion  48  of the housing  12  are made of electrically insulative materials, such as a composite or a polymer. The first portion  46  and the second portion  48  may be manufactured by a molding process. If, alternately, made of electrically conductive materials, the first portion  46  and the second portion  48  of the housing  12  may be made of a suitable, durable metal. 
     Referring now to  FIG. 10 , another embodiment of the present invention is shown as method  100  of wiring an electrical receptacle. The method  100  includes a step  102  of providing an electrical receptacle housing. The housing defines an aperture and a slot. The slot extends inwardly from a first electrical wall of the housing. An internal cavity extends from the aperture. The slot is spaced from the internal cavity and extends from a second exterior wall of the housing and terminates in a rear wall. 
     The method  100  further includes step  104  of providing a conduit fitting including a stem and step  106  of providing a nut. The method  100  further includes a step  108  of placing the nut into the slot of the housing and a step  110  of inserting the stem into the aperture of the housing. The method  100  further includes a step  112  of threading the nut onto the stem. 
     While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.