Patent Publication Number: US-10312643-B2

Title: Releasable electrical connector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/236,918 filed Oct. 4, 2015, hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Technical Field 
     The present invention relates generally to connectors for connecting electrical cables and flexible conduits to electrical panels, and more particularly to an improved connector that allows easier insertion of a cable into the trailing end of a connector and of the connector into a panel. 
     Background Art 
     The present invention relates to connectors for connecting electrical cables and flexible conduits to electrical panels. The intention of the invention is to make an improved connector that allows easier insertion of the electrical cables into the trailing end of the connector and into the electrical panel at the same time securing safe grounding. 
     Historically, armored cable (AC) or metal-clad cable (MC) has been connected to a panel by a tubular connector including a leading end having a threaded nose and a trailing end having a lateral screw mounted laterally through the connector wall or a set of strap and screws attached to the trailing end. The threaded nose was inserted into an aperture in the panel and a locknut tightened thereon to secure the connector to the panel. AC or MC cable was then inserted into the trailing end and the lateral screw or the strap screws tightened to secure the cable to the connector. It is important to secure grounding and since the connector is made out of metallic material it creates a good electrical continuity (grounding) between the electrical panel and the cable. 
     Typically electrical wiring a construction project weather it is a building or factory requires electrical contractors to make hundreds to thousands of such connections. Moreover, such installation necessitates using tools to achieve a secure connection, including a wrench on the lock nut and a screw on the laterally mounted screw. Therefore, it should be appreciated that completing all of these connections can be very time consuming, when contractors usually use such mentioned tools on each connection. 
     Recently several types of snap engagement connectors have been introduced as a means of connecting cables to electrical junction boxes in order to reduce the time and effort required for installation of connectors in electrical wiring. 
     Although using the aforementioned snap engagement connectors eliminates using tools for installation, they typically require a lot of effort to snap them on the junction box. Furthermore, if there is a need for a retrofit or disconnection of the connector, the contractors have no choice but using a tool to remove the snap engagement connectors and that in turns involves a lot of effort and force. 
     Therefore, what is needed is a connector for securing electrical cables to the junction box and the type that does not require the use of any tools for installing or removal, at either the leading or trailing end, and that allows the leading end to connect quickly and securely to the electrical junction box and the cable to be securely fitted into the trailing end. Such a connector would vastly reduce the time and effort involved for installing or removing electrical cables in a structure wiring. The desired connectors must be additionally designed to work with standard electrical panels, boxes, housings, etc., while allowing quick and easy connection with standard size knockout apertures. These and other advantages will become apparent by reading the attached summery in conjunction with reference to the attached drawings. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide an improved connector for connection of electrical cables to electrical junction boxes and panels. 
     Briefly, one embodiment of the present invention is a connector for connecting an electrical cable to an aperture in an electrical panel. The connector includes a spring ring, a shell, and a insulator that collectively have a longitudinal central axis when the connector is assembled. The spring ring has a base from which two insertion tabs bend at an angle around longitudinal central axis. Two more tabs further are bent from the far most ends of the insertion tabs around the longitudinal central axis joining in the middle and parallel with the base plate forming the gripping tabs. The two insertion tabs are perpendicular from the base plate and the two gripping tabs are parallel with the base plate. The four tabs form a square or rectangular profile conforming the shell housing. The two side insertion tabs each has a prong bent inward with jugged-in sections and free tips. The clamping tabs can have a plurality of barbs bent towards the axis with free end tips to better support gripping the cable. The insertion tabs are bent to form spring buttons. The spring buttons would pop out of the shell side openings to press and release the spring inside and out of the aperture hole. The insertion tabs have free end tips and each tip has two side extensions bent at an angle to form hook latches. The resilient insertion tabs push the hook latches against the inner wall of the panel. When the connector is pushed through the panel aperture, the hook latches slide over the edge of the opening against spring force of the insertion tabs and the latches snap into the aperture such that the side sections abut the panel around the aperture. And the hook latches are directed away from the axis to directingly extend into the aperture and snappingly lock the connector in the aperture. The spring base plate has a pressure tab extended toward the leading end along the axis with free end tip. The pressure tab has a pressure prong on the tab that is bent away from the axis with the free end tip either toward the trailing end (shown in this embodiment) or alternatively bent with the free end tip toward the leading end. The pressure tab pressure prong pushes against the shell nose and the resultant radial force provides better electrical conductivity and hence better grounding between the panel, shell, and spring. 
     These and other objects and advantages of the present invention will become clear to those skilled in the art in view of the description of the best presently known mode of carrying out the invention and the industrial applicability of the preferred embodiment as described herein and as illustrated in the figures of the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING(S) 
       The purposes and advantages of the present invention will be apparent from the following detailed description in conjunction with the appended figures of drawings in which: 
         FIG. 1  is an isometric view of an exemplary embodiment of an electrical connector according to the present invention that is aligned with a junction box or panel at a knock out hole or aperture and also aligned with an electrical cable prior to connection. 
         FIG. 2  is an isometric view of the electrical connector, junction box or panel, and cable of  FIG. 1 , wherein  FIG. 2  shows these elements after connection. 
         FIG. 3  is an exploded isometric view of the connector of  FIG. 1 . 
         FIG. 4  is exploded side view, shown on top and exploded top view, shown on bottom of the connector of  FIG. 3 . 
         FIG. 5  is back and top view of the spring on the left side and back and top view of the shell on the right side of the figure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of the present invention is an electrical connector with release and fit buttons. As illustrated in the various drawings herein, and particularly in the views of  FIGS. 1 and 2 , wherein the embodiment of the invention is depicted by the general reference character  10 .  FIGS. 1, and 2  depict one exemplary embodiment of an electrical connector  10  according to the present invention.  FIG. 1  is an isometric view of the connector  10  aligned with a knock out hole or aperture  2  in an electrical panel  1  and with an electrical cable  3  prior to connection.  FIG. 2  is an isometric view of the connector  10  after connection. As can be seen in these figures, the connector  10  secures into the aperture  2  of the panel  1  and securely receives the cable  3 . In practice, the cable  3  will support a plurality of electrical wires (not shown), which may be already present in the cable  3  or installed through the cable  3  later. 
     The transition from the pre-connection state in  FIG. 1  to the post-connection state in  FIG. 2  involves two operations. The cable  3  is pressed into locking engagement with the connector  10 , and then the connector  10  is snapped into locking engagement in the aperture  2  of the panel  1 . Alternately, the order of these operations can be reversed, snapping the connector  10  into the aperture  2  and then pressing the cable  3  into the connector  10 . How the connector  10  facilitates these snap and press together operations is discussed in detail, presently. It is helpful, however, to appreciate now and throughout this discussion that these operations are manual, here meaning that they can be performed entirely by hand and without any tools. The snap and press insertions here are also essentially linear operations, that is, not requiring any rotational screwing or locking together of pieces to employ the connector  10 . 
       FIG. 3  is an exploded isometric view of the connector  10 . As shown, the connector  10  here consists of three major components: a spring  12 , a shell  14 , and an insulator  16 . Collectively these components have a longitudinal axis  15 , as shown. 
     The spring  12  is preferably made of die-stamped and formed metal (e.g., from galvanized steel sheet), the shell  14  is preferably made of cast metal (e.g., aluminum, zinc, or pots metal), and the insulator  16  is preferably made of molded plastic (e.g., polycarbonate), although neither these particular materials or these manners of forming them are requirements.  FIG. 3  further shows the detailed features of each component. 
     The first major component of the connector  10  is the spring  12 . It is resilient and electrically conducting, and it has a base plate  58  that extends to form pressure tab  51  as the base support of the pressure prong  50 , and two insertion tabs  46  angled on the sides perpendicular to the base plate  58 . Two more tabs further are bent from the far most ends of the insertion tabs around longitudinal central axis joining in the middle and parallel with the base plate forming the gripping tabs  47 . The two insertion tabs are perpendicular from the base plate and the two gripping tabs are parallel with the base plate. The four tabs form a square or rectangular profile conforming the shell housing. The two side insertion tabs  46  each has one or more prongs bent inward with jugged-in sections and free end tips to form gripping prongs  42 . The base plate  58  also has a similar prong with a free end tip  48  bent at an angle towards the central axis  15 - 17 . The clamping tabs can have a plurality of barbs  44  bent towards the axis with free end tips to better support gripping the cable. The insertion tabs  46  are bent to form spring buttons  54 . The spring buttons would pop out of the shell side openings  32  to press and release the spring  12  inside and out of the aperture hole  2 . The insertion tabs have free end tips  41  and each tip has two side extensions barbs  40  bent at an angle to form hook latches. The resilient insertion tabs push the hook latches against the inner wall of the panel  1 . When the connector is pushed through the panel aperture  2 , the hook latches slide over the edge of opening against spring force of the insertion tabs  46 . When they pass the over the edge of aperture  2 , the spring force pushes and the latches snap into the aperture such that the side sections abut the panel around the aperture  2 . And the hook latches are directed away from the axis to directingly extend into the aperture and snappingly lock the connector  10  in the aperture  2 . The spring base plate  58  has a pressure tab  51  extended toward the leading end along the central axis with free end tip. The pressure tab has a pressure prong  50  on the tab that is bent away from the axis with the free end tip either toward the trailing end (shown in this embodiment) or alternatively bent with the free end tip toward the leading end. The spring  12  has two combined spring actions, wherein the insertion tabs  46  perform latching to the aperture  2  and the pressure tab  51  provides necessary pressure via prong  50  to securely ground the connector  10 . All insertion tabs  46  and pressure tab  51  together provide gripping cable  3  with the support of gripping tabs  47  while securing grounding continuation through cable  3 . 
     The base plate  58  and the extended side insertion tabs  46  nominally conform to the inner rectangular shape of the shell  14  to permit insertion of a cable  3 . The base plate  58  is at a defined trailing end of the connector  10 , thus also defining an opposite leading end of the connector  10  (on the insulator  16 , left most in  FIG. 3 ). 
     The two insertion tabs  46  can be the same in general shape. Each extends, as shown, from opposite sides of the base plate  58  at an angle of 90 degrees or less. The insertion tabs  46  have a extruded section that forms a fit/release button, described presently. The insertion tabs  46  are further each extended to form respective hook latch bases. The hook latch bases have two angled barbs  40  on the side of the tab end tip, as shown. As also shown, the barbs  40  can optionally have a triangular or curved cutout between adjacent pairs to permit better grip on the inner wall of a panel  1 . The corners of the barbs can also operate to penetrate through a paint or oxidation layer on the inner wall, to reach an underling metal wall material of the panel  1  and thus provide better electrical conductivity and grounding. 
     Two locking tabs  56  bend outward from the two insertion tabs  46  to secure the spring inside the shell from pulling out. Each insertion tab  46  provides a base from which one or more prongs extend at an angle less than 90 degree to form the side gripping prongs  42 . The two gripping prongs  42  can also have the same shape, but preferably there are minor differences to facilitate better engagement with the spiral or helix shaped sides of a cable  3 . An inward bent prongs from base plate  58  forms the gripping prong located on top  48 . In  FIG. 3  one of the insertion tabs  46  is clearly presented, whereas the other one is almost entirely hidden behind other structure along with the gripping tabs  47 . The respective prongs in each of these sets can also be the same in size and degree of inward bend, but preferably are slightly different, again to facilitate better engagement with the spiral or helix shaped sides of a cable  3 , and thus better securing the cable  3  inside the connector  10 , providing better electrical conductivity and grounding. 
     The second major component of the connector  10  is the shell  14 . It is rigid, typically also electrically conducting, and, as shown, it has a nominally square or rectangular cross section. The shell  14  has a base  27 , two support columns  26 , one trailing bridge  30 , and two trailing side bridges  33  forming the trailing opening  31 . Further the base  27  and two columns  26  terminate in to a perpendicular plate  28  forming a base for the leading nose  20 , two opening windows  32  through which spring buttons  54  extrude out, and an opening  29  on top shown in  FIG. 5  through which the spring pressure tab  51  passes. The leading nose  20  extends out of perpendicular plate  28  towards the leading end shown in  FIG. 3  forming a flat base  22  to support spring pressure tab  51 , two opening windows  21  through which the spring hook latch base and barbs  40  extends outwards. The leading nose  20  forms a collar that sits against the aperture  2  and it has an forward opening  25  through which the electrical conductors (not shown) of the cable  3  passes. The plate  28  also has a corresponding opening to the opening  25  to allow passage of the conductors through (not shown). The hole  25  further receives the insulator  16 . In the back of the plate  28 , facing the trailing end, there is a recessed cut  34  on which the insulator  16  snaps securely through a plurality of two or more snapping legs  70 , here  4  legs. 
     The third major component of the connector  10  is the insulator  16 . It has two guiding bodies  61  and  62  extending out of ring or base  60  having a circular or oval opening  68 . The guiding bodies  61  and  62  match the contour of the shell  14  and slide through hole  25 . The insulator  16  is completed by a plurality of snapping legs  70  (four here, two visible in  FIG. 3  and four visible in  FIG. 4 ). 
     To assemble the embodiment of the connector  10  depicted in  FIG. 3  the spring ring  12  is inserted in a first operation into the through opening  31  of the shell  14  and then the insulator  16  is inserted in a second operation into the through opening  25  of the shell  14 . 
     The first insertion operation includes inwardly displacing the press sections  54  of the insertion tabs  46  sufficient to permit passage of the insertion tabs  46  between the side bridges  33  of the shell  14 . At the same time, the pressure tab  51  slides underneath trailing bridge  30  and sits over flat area  22  of shell  14 . A final press slides the spring  12  tightly inside shell  14 . Once the spring  12  is brought to its final position in the shell  14 , the two locking tabs  56  snap out of openings  32  on shell  14  fitting spring  12  firmly inside shell  14  securing strong electrical conductivity and grounding between spring  12  and shell  14 . Once the spring  12  is brought to its final position in the shell  14 , the two spring buttons  54  pop out of two openings  32  and the insertion tab spring back displacement constrains base  41  on each insertion tab  46  against columns  35  of plate  28 , thus trapping the spring  12  in the shell  14 . In this manner the spring buttons  54  are used as fit buttons during assembly (and can be used as release buttons for disassembly). 
     The second insertion operation includes snapping the insulator  16  into the sub-assembly of the shell  14  and spring  12 . The insulator  16  is passed into the through opening  25 , sliding two guiding bodies  61  and  62  inside opening  25  with the snapping legs  70  of the insulator  16  against the recessed area  34  of the shell  14 , thus locking the insulator  16  within the sub-assembly of the shell  14  and spring  12 . 
     To connect the connector  10  to a panel  1 , the spring buttons  54  of the insertion tabs  46  are pressed, thus inwardly moving the hook latches barbs  40  enough to pass the leading end of the connector  10  into an aperture  2 . When then released, the insertion tabs  46  bounce back, outward, to grip into the inner wall of the panel  1  through barbs  40 . 
     To connect a cable  3  to the connector  10 , the cable  3  is pushed through the hole  31  at the trailing end of the connector  10 , until the cable  3  abuts against the insulator  16 , where it is then locked into place by the grip of the prongs (e.g., by the prongs  44  of clamping tab  47 , the prongs  44  of base plate  58 , and prongs  42  of insertion tabs  46 ). 
     To disconnect the connector  10  from the panel  1 , the spring buttons  54  of the insertion tabs  46  are again pressed, thus inwardly moving and disengaging the hook latches, disengaging barbs  40  enough to remove the leading end of the connector  10  from the aperture  2 . 
     To disconnect the connector  10  from the cable  3 , the connector  10  can be rotated counter-clockwise to unscrew the connector  10  from the cable  3  (since the prongs  44  of clamping tab  47 , the prongs  44  of base plate  58 , and prongs  42  of insertion tabs  46  are in screw-thread-like engagement with the spiral groove of the cable  3 ). 
     In summary, it can now be appreciated that the connecting and disconnecting of cables  3  to panels  1  with the connectors  10  can be entirely manual, requiring little effort and no tools. The linear connecting operations of squeezing and inserting a connector into knock out hole or aperture and pressing a cable into the connector permitted by the present connector  10  should especially permit time savings during electrical construction. Similarly, to the extent rarely ever needed, the linear disconnecting operation of squeezing and withdrawing the present connector  10  from a knock out hole or aperture and the rotational disconnecting operation of unscrewing the present connector  10  from a cable will also permit time savings over the use of other types of connectors. 
     The present invention offers a quick connect connector for an electrical junction box or panel that requires no tools for connection or removal of the connector. Moreover, it needs much less effort and force for installation or removal compared to the existing snapping connectors. Due to its unique design, there are large contact areas between the electrical junction box or panel, the connector, and the jacket of the electrical cable that in turn results in a very good electrical continuity and grounding. 
     While various embodiments have been described above, it should be understood that they have been presented by way of example only, and that the breadth and scope of the invention should not be limited by any of the above described exemplary embodiments, but should instead be defined only in accordance with the following claims and their equivalents.