Abstract:
An example electrical connector includes a non-electrically-conductive housing carrying at least a pair of opposed flexible, electrically-conductive push-in type contacts. The contacts each having a first end configured to receive and grip an electrical conductor, and a second end having a contact portion to releasable electrically couple with a corresponding conductive strip housed on opposite sides of an upper rail of a corresponding low voltage direct current grid member. In one example, a strain relief mechanism is coupled to the housing and is adapted to mechanically couple to the inserted electrical conductor and to assist in retaining the inserted electrical conductor in the push-in type contact. The housing may also define at least a pair of first interior spaces enclosing the first end of each of the contacts and for receiving and gripping the electrical conductor.

Description:
FIELD OF THE DISCLOSURE 
     The present description relates generally to electrical connectors and more particularly to a connector having a push-in termination for an electrically active grid. 
     BACKGROUND OF RELATED ART 
     Connectors and more particularly, connectors for making low voltage direct current electrical connection between conductive elements are known in the art. In particular, in one known application of a low voltage DC system, an electrified framework brings power and/or signals to an electrically powered device connected to the framework through specialized connectors. 
     For example, U.S. Pat. No. 7,997,910, hereby incorporated by reference in its entirety, describes an electrified framework system having a grid element which includes a top portion having a pair of conductors for distributing low voltage electricity disposed thereon. The conductors have opposing polarity and are disposed on opposing surfaces of the top portion of the grid element. The prior system also includes a connector which is mounted on the top portion of the grid element. The connector includes two conductive wire crimp contacts to provide a low voltage power connection between the pair of conductors and another conductive element capable of distributing low voltage electricity. 
     Meanwhile, U.S. Pat. No. 8,062,042, hereby incorporated by reference in its entirety, similarly describes an electrified framework for bringing low voltage direct current power to various connected devices. In this described example, the framework includes an electrified bus bar such as those commonly used in suspended ceiling systems utilizing lay-in panels. The example bus includes a pair of conductors disposed on opposing surfaces of the top portion of the bus, and a pair of longitudinally extending electrifiable conductors positioned inside a lower flange portion of the bus to form an internal bus bar. In the described example, an electrical connector straddles over top of the support grid member and includes a conductive material extending downwardly from the top portion o f the grid member until a second exposed portion can mate with the lower conductor through a predefined access slot. 
     The connector of U.S. Pat. No. 7,997,910 utilizes a wire crimp (e.g., a spring) to hold a wire in the connector housing. The spring does the work of holding the wire in the connector, and yet is subject to misalignment and disconnection due to movement and/or strain on the wire. Because the grid is typically utilized in confined spaces, the wire problems with the prior art are oftentimes exaggerated. 
     The connector of U.S. Pat. No. 8,062,042, meanwhile provides for a clamping type connection between the upper and lower conductors of the grid itself The example connector does not provide for an interface between the grid and an external electrical device. 
     Accordingly, there is an identifiable need for a connector that is adapted for use with a low-voltage DC power grid including an electrified grid framework. The disclosed example connector provides for a push-in type contact for securely accepting multiple conductor sizes, and/or a conductor types. The disclosed connector that provides for the proper seating of an inserted wire within the housing of the connector, as well as a strain relief to hold the wire securely within the connector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a section of a prior art grid member for use with an example connector in accordance with the present disclosure. 
         FIG. 2  is a perspective view of an example connector of the present disclosure attached to the grid member of  FIG. 1 . 
         FIG. 3  is an exploded perspective view of the example connector of  FIG. 2 . 
         FIG. 4  is a right side cross-sectional view of the example connector of the present disclosure taken along line  4 - 4  of  FIG. 2 . 
         FIG. 5  is a perspective cross-sectional view of the housing of the example connector of the present disclosure taken along line  5 - 5  of  FIG. 3 . 
         FIG. 6  is a perspective cross-sectional view of the example connector of the present disclosure taken along line  4 - 4  of  FIG. 2  with the grid member removed. 
         FIG. 7  is a perspective view of the cap of the example connector of the present disclosure. 
         FIG. 8  is a top plan view of the example cap of  FIG. 7 . 
         FIG. 9  is a perspective view of the example cap of  FIG. 7  showing an example strain relief mechanism in an open position. 
         FIG. 10  is a top plan view of the example clip of  FIG. 9 . 
         FIG. 11  is a perspective view of the example cap of FIG,  9  showing the example strain relief mechanism in a closed position. 
     
    
    
     DETAILED DESCRIPTION 
     The following description of example electrical connectors is not intended to limit the scope of the description to the precise forms detailed herein. Instead the following description is intended to be illustrative so that others may follow its teachings. 
     Referring now to  FIG. 1 , an example of a prior art grid member  2  for forming an electrified framework, such as a ceiling grid framework, is shown. The grid member  2  may be utilized in any system having a grid framework, including floors and wall. The grid member  2  is adapted to support decorative tiles, acoustical tiles, insulative tiles, lights, heating ventilation and air conditioning (HVAC) vents, other ceiling elements or covers and combinations thereof. Low voltage devices, such as light emitting diode (LED) lights, speakers, smoke or carbon monoxide detectors, wireless access points, still or video cameras, or other low voltage devices, may utilize the electrified ceiling for power and/or signal connectivity. 
     In the example grid member  2 , a conductive material is disposed on a surface of the grid member. Specifically, first and second conductive strips  4  and  4 ′ are disposed on the grid element  2 , and specifically, a top portion  6 , e.g. bulb portion thereof. The conductive strips  4 ,  4 ′ have opposite polarity, i.e. one is positive and one is negative. The grid member  2  includes a vertical web  7  extending between the top portion  6  and a lower portion  8 , such as a flange for supporting the tiles. The web  7  includes a plurality of keying slots  9 , which is angled, or sloping, and which is precisely positioned in the vertical web of the grid member at a pre-determined location. 
     One or more connectors is needed to provide low voltage power connections. For example, a connector is needed to bring power from a power supply to the conductive strips  4 ,  4 ′ disposed on the grid member  2 . Additionally, a connector is needed to provide an electrical connection between the conductive strips  4 ,  4 ′ on the grid member  2  and a device such as a light. The example connector described in greater detail below may provide is capable of supplying the power necessary. 
     Specifically, referring to  FIGS. 2-6 , an example connector  10  is illustrated as electrically and mechanically mated to the grid member  2 . The connector  10  provides a means for bringing power, or electricity, from a power supply to the conductive strips  4  and  4 ′ disposed on the grid member  2  or, in the alternative, from the already electrified conductive strip  4  and  4 ′ to various low voltage devices. 
     As best seen in  FIGS. 3 and 4 , the example connector  10  includes two conductive, push-in type, electrical contacts  12  and  12 ′, a nonconductive, insulative housing  14 , a cap  16 , and an outer clamp  18 . Each electrical contact  12 ,  12 ′ includes a first contact potion  20  and a second contacting portion  22 . The first contacting portion  20  of the contact  12 ,  12 ′ includes a resilient portion, such as for example, a spring finger for contacting, retaining, and electrically coupling with a wire  24  inserted through the cap  16 . The second contacting portion  22  of the contact  12 ,  12 ′ also includes a resilient portion such as a contact spring, which is compliant and upon installation is brought in contact with, i.e. taps, the conductive strips  4 ,  4 ′ disposed on the top portion  6  of the grid member  2 . Upon installation, together, the grid member  2  and the housing  14  enclose the second contacting portion  22  of each of the contacts  12 ,  12 ′. 
     In at least one example, the housing  14  and the cap  16  are formed of a non-conductive material such as, for example, a thermoplastic material. The housing  14  and/or the cap  16  may further be formed of a flexible material to allow the insertion of the cap  16  into the housing  14 , as will be described below, the insertion of the housing  14  over the grid member  2 . It will be appreciated by one of ordinary skill in the art, however, that the material used to form the housing  14  and the cap  16  need not be the same material, and furthermore, may be any suitable material including thermoplastic, thermoset, conductive, and non-conductive materials alike. 
     In this example, the connector  10  comprises an optional location/polarization feature. In particular, this feature is designed to assure that the connector  10  can only be installed and fully engaged at pre-determined locations on the grid member  2 . More specifically, the polarization feature, an example of which is shown in  FIG. 5  is a pair of molded, flexible wings  30  extending from the lower portion of the housing  14 . The wings  30  are sufficiently thin and/or flexible such that during installation, the wings  30  can separate such that the housing  14 , and thus the connector  10  can be inserted over the top portion  6  of the grid member  2 . A protrusion  32  on each wing  30  engages and passes through the keying slot  9 , which is angled, or sloping, and positioned in the vertical web  7  of the grid member  2  at pre-determined locations. Only when this protrusion  32  of the wing  30  is in proper alignment and seated in the sloping keying slot  9 , will the outer clamp  18  be capable of being fully seated on the connector housing  14 . 
     Referring to  FIGS. 5 and 6 , together, the housing  14  and the cap  16  partially enclose the two contacts  12 ,  12 ′ mounted in an interior space  40  defined by an upper portion of the housing  14 . The interior space  40  includes an open end  42  to receive the cap  16 . The housing  14  defines at least one aperture  44  proximate to the open end  42  of the interior space  20 . The aperture  44  is adapted to engage a corresponding hook  46  (see  FIGS. 7 ,  8 ) which protrudes from the cap  16  to retain the cap  16  in the housing  14 . Additionally, the example cap  16  has a pair of ports  48  extending through the cap  16 . These ports  48  provide access to, and guide the insertion of the wire  24  into the interior space  40  of the housing. 
     Still further, in the illustrated example, each of the hooks  46  includes a cammed surface and a stepped surface to securely engage the hooks  46  in a corresponding aperture  44  in a snap-fit arrangement. As will be appreciate by one of ordinary skill in the art, in the example shown, the proper seating of each of the hooks  46  in the proper aperture  44  will provide an externally visible confirmation of the proper seating of the cap  16  within the housing  14 . For instance, if the cap  16  is not properly seated, the cammed surface will force the housing  14  defining the opening  40  outwards from the cap  16 , providing a visual and physical indication that the cap  16  is improperly seated in the housing  14 . In still other examples, the hook  46  may be provided with a color indicator and/or other visual marker to identify when the cap  16  is properly retained in the housing  14 . 
       FIGS. 5-6  also illustrate the interior features of the housing  14 . In the illustrated example of  FIG. 5  both the contacts  12 ,  12 ′ and the cap  16  typically located within the housing  14  have been removed for ease of illustration, while in  FIG. 6 , the entire connector as assembled is illustrated in cross-section. In this example, the housing  14  generally defines two contact and wire receiving compartments  50 A and  50 B. Each of the compartments  50 A,  50 B includes an contact compartment  52  and a wire receiving compartment  54 . The contact compartment  52  is adapted to partially accept the contact  12 ,  12 ′ and more specifically, the second contact portion  22 . The wire receiving compartment  54 , meanwhile is generally a four-sided compartment sized to retain the first contact portion  20  and to accept the wire  24 , such as an  14  awg stranded wire, inserted through the ports  48  formed in the cap  16 . It will be understood by one of ordinary skill in the art that the ports  48  and the compartments  50 A,  50 B may be sized to accept any size and/or type of suitable contact and/or wire such as larger/smaller contacts and wires of larger and/or smaller gauge as well as stranded and/or solid wires. As illustrated in  FIG. 5 , the walls of the wire receiving compartments  54  may be tapered in cross section to pinch and/or otherwise constrict the wire  24  when inserted into the housing  14 . 
     In the illustrated example, dividing the contact compartment  52  and the wire receiving compartment  54  is a spring stop  60 . The spring stop prevents over-deflection of the first contact portion  20  and also cooperates with the walls of the wire receiving compartment  54  to properly seat the inserted wire  24  in the wire receiving compartment  54 . In operation, the wire receiving compartment  54  also constrains the wire  24  to a confined area which may be of particular importance for some conductors, such as for example, with stranded wire conductors because the confined seats prevent the conductors from flattening out or splaying, which if it occurred could cause a reduction in the holding force of the push-in type contact elements  12 ,  12 ′. As noted, the spring stop  60  may also limit deflection of the spring finger of the contact elements  24 . With the larger wire sizes it may be possible to cause plastic deformation of the first contact portion  20  during insertion of the wire  24 , and thus the spring stop  60  is disposed in the path of the first contact portion  20  to limit flexure of the first contact portion  20  to an amount no more than its elastic limit. 
     The outer clamp  18  can be used to secure the housing  14  on the grid member  2 . The example clamp  18  is made of rigid, yet somewhat resilient material, and snaps over the housing  14 . Although the clamp can be installed, or even pre-assembled, on the housing prior to attaching the connector to the grid element, the clamp can be installed in at least two other ways to minimize insertion forces. First, the clamp can be installed after fully seating the housing on the grid element to provide for low insertion forces. Alternatively, the clamp can be partially installed on the housing in an up position and then fully seated after the housing is in the fully mated position which also provides low insertion forces but require the clamp to be pre-assembled on the housing. In one example, the clamp  18  includes at least one aperture  62  adapted to engage a corresponding hook  64  which protrudes from the housing  14  to retain the clamp  18  on the housing  14  when the clamp is fully installed. 
     In one example, illustrated in  FIGS. 9 and 10  an alternative cap  16 ′ having means for relieving strain on the wire  24  may be utilized in place of the cap  16 . In this example, the cap  16 ′ is identical to the cap  16  but includes an addition of a strain relief mechanism  70 . In the illustrated example, the strain relief mechanism  70  is a ratchet-type retainer adaptable to mate with wires of various sizes. For instance, in this example, the strain relief mechanism  70  includes a rotatable arcuate portion  72  and a stationary ratchet  74 . The rotatable arcuate portion  72  includes a plurality of ratchet teeth  76  to contact and releasable engage the ratchet  74  when the rotatable portion  72  is rotated towards the ratchet  72 . In this example, the rotatable portion  72  is provided with a handle  78  to assist in the rotation of the rotatable portion  72  towards the ratchet  72 . 
     As will be appreciated, the ratchet  74  may include a release mechanism  80  that when depressed, provide a deflection of the ratchet  72  sufficient to allow the arcuate portion  74  to rotate away from the ratchet  72 . It will further be appreciated that in operation, the strain relief mechanism  70  is closed about the wire  24  to grip the outer surface of the wire  24  and provide a sufficient strain relief to avoid the unintended release of the wire  24  from the housing  14 . Additionally, it will be understood by one of ordinary skill in the art that while the strain relief mechanism  70  is described as a ratchet-type mechanism in the present disclosure, strain relief may be provided by any suitable mechanism including, for example, a spring, a clip, an overmould, a bushing, and/or any other suitable mechanism. 
     Still further it will be appreciated that while the example connector  10  is described as containing a pair of connectors maintaining a single wire in each contact, it will be appreciated that in some instances, their may be multiple connectors marinating multiple wires as desired. For example, in some instances, multiple wires may be inserted into a single finger. 
     Furthermore, it will be understood that throughout this description, relative designations such as “top”, “bottom”, “front”, “rear”, “down”, “up”, etc, are used herein for reference purposes only, as there is nothing inherent in the orientation of the example disconnects that would make a particular orientation necessary. 
     Although certain examples have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus, and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.