Patent Publication Number: US-9419352-B2

Title: Terminal block with ground strap, spring force terminals, and screw lug terminal

Description:
FIELD 
     The aspects of the present disclosure relate generally to terminal blocks for electrical power distribution. In particular, the aspects of the disclosed embodiments are directed to an improved terminal block for electrical power distribution to luminaires. 
     BACKGROUND 
     In the distribution of electric power, terminal blocks, also called distribution blocks are often employed. The applications for these terminal blocks can vary widely and include for example, luminaire test fixtures. A luminaire test fixture, which is generally used during a luminaire manufacturing process can include a source of electrical power, and a ballast. The terminal block is used to couple the electrical power to the ballast, or other driver for the luminaire. 
     Typically the terminal block includes a connection for a larger conductor cable or bus and a plurality of tap connections for smaller conductors. In a common application, the bare ends of the conductors are inserted in socket ports or holes in the distribution block. A clamp or binding screw is threaded into a hole perpendicular to the socket receiving the conductor to hold or secure the conductor in place, in an electrically conductive manner. In some cases push-on terminal flag type terminals or connectors can be used as the tap connections for the smaller conductors. The flag terminal end of the conductor is received on a flag terminal end disposed on the terminal block. 
     The use of the typical terminal block in the luminaire manufacturing process will generally require crimped connectors, additional leads, additional connectors, dedicated ground screws and additional ground eyelets. The power line leads providing the source of electrical power will be received in the socket ports and held in place when the screw is tightened down. The leads or conductors leading to the luminaire, referred to as “driver” leads will generally have the crimped terminal flag connectors that allow them to be connected to the terminal block. Very often, there will be multiple conductors per terminal flag connection. 
     It can be impractical during the manufacturing process to assemble crimp connectors to the driver leads, which requires additional leads to be manufactured with crimp terminals. When additional leads are required, it necessitates the need for additional connectors to connect driver/ballast leads. Also, a dedicated ground screw and additional round eyelet are required to ground the luminaire to the ground pole of the terminal block. It would be advantageous to provide a terminal block that eliminates the need for crimped connectors, additional leads and connectors, dedicated ground screws, and ground eyelets. 
     Accordingly, it would be desirable to provide a terminal block that addresses at least some of the problems identified above. 
     BRIEF DESCRIPTION OF THE DISCLOSED EMBODIMENTS 
     As described herein, the exemplary embodiments overcome one or more of the above or other disadvantages known in the art. One aspect of the exemplary embodiments relates to a terminal block assembly. In one embodiment, the terminal block assembly includes a housing, a housing retention member coupled to the housing, a plurality of screw lug terminal assemblies disposed within the housing, a plurality of push-in terminal assemblies disposed within the housing, wherein a push-in terminal of the plurality of push-in terminal assemblies includes a strain relief member, and a retention spring assembly comprising a finger member and a conductor member, the conductor member electrically coupling the finger member to a corresponding screw-lug terminal assembly, a bottom portion of the strain relief member engaging the conductor member of the retention spring assembly to retain the retention spring assembly within the housing, and a ground strap disposed within the housing and extending to the housing retention member, wherein the ground strap is electrically coupled to one screw lug terminal assembly of the plurality of screw lug terminal assemblies. 
     These and other aspects and advantages of the exemplary embodiments will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Moreover, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate presently preferred embodiments of the present disclosure, and together with the general description given above and the detailed description given below, serve to explain the principles of the present disclosure. As shown throughout the drawings, like reference numerals designate like or corresponding parts. 
         FIG. 1  is a perspective view of an exemplary terminal block assembly incorporating aspects of the disclosed embodiments; 
         FIG. 2  is a top view of the terminal block of  FIG. 1 ; 
         FIG. 3  is a side view of the terminal block of  FIG. 1 ; 
         FIG. 4  is a partial assembly view of the terminal block of  FIG. 1 ; 
         FIG. 5  illustrates the terminal block of  FIG. 1  with leads and a lead removal tool; 
         FIG. 6  is a cross-sectional view of the terminal block of  FIG. 1  taken along the line E-E; 
         FIG. 7  is a bottom view of the terminal block of  FIG. 1 ; 
         FIG. 8  is a cross-sectional view of the terminal block of  FIG. 1  taken along the line G-G; 
         FIG. 9  is a front view of the terminal block of  FIG. 1 ; 
         FIG. 10  is a cross-sectional side view of the terminal block of  FIG. 1 , taken along the line A-A of  FIG. 9 . 
         FIG. 11  illustrates an exemplary spring retention member incorporating aspects of the disclosed embodiments; 
         FIG. 12  is a perspective view of an exemplary terminal block assembly incorporating aspects of the disclosed embodiments; 
         FIG. 13  is a top view of the terminal block of  FIG. 12 ; 
         FIG. 14  is a partial assembly view of the terminal block of  FIG. 12 ; 
         FIG. 15  illustrates an exemplary retention spring assembly incorporating aspects of the disclosed embodiments; 
         FIG. 16  is a front view of the terminal block of  FIG. 12 ; and 
         FIG. 17  is a side cross-sectional view of the terminal block of  FIG. 12  taken along the line A-A of  FIG. 16 . 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THE DISCLOSURE 
       FIG. 1  illustrates a perspective view of one embodiment of a terminal block assembly  100  incorporating aspects of the present disclosure. The terminal block assembly  100  of the disclosed embodiment improve manufacturing efficiencies during the luminaire manufacturing process. For example, the improved terminal block assembly  100  of the disclosed embodiments may eliminates or reduce the need for components such as crimped connectors, additional leads, additional connectors, dedicated ground screws, and additional ground eyelet. While the aspects of the disclosed embodiments are generally described herein with respect to a luminaire manufacturing processes, the aspects of the disclosed embodiments are not so limited. In alternate embodiments, the terminal block assembly  100  can be implemented in any suitable application where electrical power is distributed. 
     As shown in  FIG. 1 , in one embodiment, the terminal block assembly  100  includes a housing  102 , one or more screw lug terminal assemblies  104 , one or more push-in terminal assemblies  106  and an integrated grounding strap  108 . In one embodiment, the housing  102  comprises a non-conductive, elastomeric material, as is generally understood. In the example of  FIG. 1 , the terminal block assembly  100  includes three screw lug terminal assemblies and three corresponding push-in terminal assemblies. In alternate embodiments, the terminal block assembly  100  can include any suitable number of screw lug terminal assemblies and corresponding push-in terminal assemblies, such as more or less than three. 
     In one embodiment, the housing  102  includes one or more retaining members  110 . Referring to  FIGS. 1 and 2 , there is a retaining member  110  on either side of the housing  102 . The retaining member  110  is generally configured to secure the terminal block assembly  100  to a fixture (not shown). In alternate embodiments, any suitable number of retaining members can be implemented in any suitable locations to secure the terminal block assembly  100  to any suitable fixture. 
     Referring to  FIG. 2 , for example, the retaining member  110  includes an aperture  112  that allows a fastener (not shown) to be inserted to secure the housing  102  to a corresponding fixture (not shown). In one embodiment, the retaining member  110  comprises a bracket portion of the housing  102 . 
     Referring also to  FIG. 4 , the screw lug terminal assembly  104  generally comprises a conductor receiving member  402  and a conductor retaining member  404 . The screw lug terminal assembly  104  comprises a conductive material, such as tin plated aluminum for example. In alternate embodiments, the screw lug terminal  104  can comprise any suitable conductive material, other than including tin plated aluminum. In the example of  FIG. 1 , there are three screw lug terminal assemblies  104 , one for each leg or phase of the power connection, such as L1, Ground and L2 or Neutral. In alternate embodiment, there can be any suitable number of screw lug terminals assemblies, such as two or four, for example. 
     In the example of  FIG. 4 , the conductor receiving member  402  comprises a conductive block, also referred to as a lug, with an opening or aperture  406 . The aperture  406  is configured to receive a stripped end of a conductor, as is generally illustrated in  FIG. 5 . The conductor retaining member  404  in the example of  FIG. 4  is a screw that engages a threaded portion  408  of the lug  402 . Once the stripped end of the conductor is inserted into the aperture  406 , the screw  404  is tightened to retain and electrically couple the conductor within the screw lug terminal assembly  104 . An example of this is shown in  FIG. 5 . 
     As is illustrated in  FIG. 5 , the terminal block  100  is a junction between field leads  502  and manufacturing leads  504 . In the examples describe herein, the field leads generally comprise electrical power leads. Typically, the field or power leads  502  will be, for example, #6 to #16 (Solid or Stranded) copper wire or #6 (Solid or Stranded) aluminium wire. In alternate embodiments, the screw lug terminal assemblies  104  can be configured to accept any suitably sized conductor leads, depending upon the specific application. Although a screw lug type of terminal assembly is illustrated as being used to couple the field leads  502  within housing  102  of the terminal block assembly  100 , in alternate embodiments, the field leads  502  can be electrically coupled and secured in any suitable manner, other than including a screw lug terminal. 
     The terminal block assembly  100  is configured to permit the stripped ends of the manufacturing leads  504  to be pushed directly into the push-in terminal assembly  106  without the need of tools or crimped connectors. Referring to  FIGS. 4, 6 and 10 , in one embodiment, the push-in terminal assembly  106  generally comprises a strain relief/wire cap member  410  and a retention spring member  420 . The push-in terminal assembly  106  is configured to allow the stripped end of a lead  504  to be inserted into one of the lead openings  414  in the strain relief member  410 . The strain relief member  410  generally comprises a thermoplastic or other suitable non-conductive material. 
     In one embodiment, the strain relief member  410  is removably retained in a corresponding opening in the housing  102 . As shown in  FIG. 4 , in one embodiment, the strain relief member  410  includes one or more tab members  412  on the side portions of the strain relief member  410  that are configured to allow the strain relief member  410  to “snap-in” the corresponding opening in the housing  102  without destroying or damaging a functionality of the strain relief member  410  and the terminal block assembly  100 . Although tab members are illustrated in the example of  FIG. 4 , in alternate embodiments, the strain relief member  410  can be retained in the housing  102  in any suitable manner that allows the strain relief member  410  to be inserted without damage to either the strain relief member  410  or housing  102 . 
     As shown in  FIGS. 4 and 5 , the top portion of the strain relief member  410  includes one or more lead openings  414 . The lead openings  414  are configured to accommodate the manufacturing leads  504 . In one embodiment, the one or more of the openings  414  have different sizes to accommodate different sized manufacturing leads  504 . In the example of  FIG. 4 , the strain relief member  410  includes an arrangement of four lead openings  414 . In alternate embodiments, the strain relief member  410  can include any suitable number of lead openings  414  in any suitable arrangement.  FIG. 13  illustrates another exemplary arrangement of lead openings  414  incorporating aspects of the disclosed embodiments. 
     The retention spring member  420  generally comprises a conductive spring member. In one embodiment, the retention spring member  420  comprises a tin plated copper alloy. In alternate embodiments, the retention spring member  420  can comprise any suitable conductive material, such as a tin plated phosphor bronze. 
     In the example shown in  FIG. 4 , the retention spring member  420  comprises one or more finger members  422 , a base portion  424  and a blade conductor portion or member  426 . The one or more fingers members  422  are coupled to or integrated with the base portion  424 . When a manufacturing lead  504  is inserted into a lead opening  414 , the stripped end of the manufacturing lead will engage a respective finger member  422  to secure the lead  504  within the push-in terminal assembly  106  as well as establish an electrical connection between the manufacturing lead  504  and the finger member  422 . 
     As is shown in  FIG. 4 , in one embodiment, there are finger members  422  on either side of the retention spring member  420  that define an opening or space  428  between the finger members  422  on each side. As will be described further below and is shown in  FIG. 6 , the opening  428  is suitably size to allow the blade portion  416  of the strain relief assembly  410  to be inserted therebetween. 
     The blade conductor member  426  of the retention spring member  420  is configured to engage a respective screw-lug terminal assembly  104  to electrically couple the retention spring member  420  to the respective screw-lug terminal assembly  104 . The blade conductor  426  provides the electrical continuity between the leads  504  and the screw lug terminal  106 . In the example shown in  FIG. 4 , the retention spring member  420  is a one piece assembly. Alternatively, such as in the embodiment shown in  FIG. 14 , the retention spring member  420  can comprise one or more parts that are electrically coupled together. 
     As is shown in  FIG. 4 , the blade portion  416  of the strain relief assembly  410  is narrower than the top portion of the strain relief member  410 . In alternate embodiments, the blade portion  416  can be any suitable size and shape. The blade portion  416  is configured to extend downwards and be received within the opening  428  between the fingers  422  of the retention spring member  420 . The bottom of the blade portion  416  will engage the blade conductor  426  to secure the retention spring member  420  in position within the housing  102 . 
     The cross-sectional view of  FIG. 6  shows the finger portions  422  of the retention spring member  420  pressing against the blade portion  416  of the strain relief assembly  410 . When the stripped end of the manufacturing lead  504  is inserted into a corresponding lead opening  414 , the stripped end of the lead  504  exerts pressure on the respective finger portion  422  to push the finger portions  422  away from the blade portion of the strain relief assembly  410 . The stripped end of the lead  504  is retained between the retention spring member  420  and the blade portion  416  of the strain relief member  410 . The retention spring member  420  is configured to maintain a constant pressure against the leads  504  and the blade portion  416 . 
     The finger portion  422  of retention spring member  420  corresponding to an opening  414  is configured to press the stripped end of the lead  504  against the blade portion  416  to securely retain the lead  504 . As is shown, there can be one or more lead openings  414  per strain relief member  410 , which allows one or more manufacturing leads  504  to be electrically coupled, via the respective retention spring member  420  to a respective screw-lug terminal  104 . 
     The terminal block assembly  100  of the disclosed embodiments is configured to allow the manufacturing leads  504  to be electrically coupled to the field leads  502  without the need for tools or crimped connectors. In one embodiment, the stripped end of a lead  504  is pushed through an opening  414  in the strain relief assembly  410 . The stripped end of the lead  504  will depress, push aside or otherwise move, the finger member  422  of the retention spring assembly  420 . In alternate embodiments, levers or push buttons can be used to depress the fingers member  422  before inserting the leads  504 , and then released to retain the leads  504  as described herein. 
     The movement of the finger member  422  will allow the stripped end of the lead  504  to slide between the blade portion  416  and finger member  422  of the retention spring assembly  420 . The flexible or spring like nature of the finger member  422  of the retention spring assembly  420  will allow the finger member  422  to maintain a substantially constant pressure against the stripped end of the lead  504 . Thus, the retention spring assembly  420  will be electrically coupled to the lead  504 . 
     The blade conductor  426  of the retention spring assembly  420  provides the electrical continuity between the leads  504  and the lug terminal  104 . When a field lead  502  is electrically coupled to the screw lug terminal  104 , the field lead  502  will be electrically coupled to the corresponding manufacturing lead  504 . As was noted, there can be one or more leads  504  per push-in terminal  106 , which are then electrically connected to the corresponding screw-lug terminal  104 . 
     Referring to  FIGS. 7 and 8 , for example, in one embodiment, the terminal block assembly  100  includes an integrated ground strap  108 . The ground strap  108  comprises a conductive member such as a tin plated copper alloy. In alternate embodiments, the ground strap  108  can comprises any suitable conductive material, such as a tin plated brass. The ground strap  108  is configured to provide an electrical ground path for the device, such as a luminaire, without the need for grounding straps. 
     As is shown in the cross-sectional views of  FIG. 8 , the ground strap  108  is over-molded in the housing  102 . When mounting the terminal block assembly  100  to the luminaire, or other device, an electrical ground path is established, without then need for additional conductors. For example, the ground strap  108  provides a ground path is in lieu of having to connect a green jumper ground lead from the ground terminal of the terminal block to the luminaire housing. 
     As is shown in  FIG. 8 , the ground strap  108  extends through the body of the housing  102 . A portion  802  of the ground strap  108  is disposed within the retaining member portion  110  of the terminal block assembly  100 . In one embodiment, the portion  802  of the ground strap  108  circumscribes the aperture  112 . When a conductive screw is inserted into the aperture  112  of the retaining member  110 , the screw makes electrical contact with the portion  802  of the ground strap  108 . The screw can be coupled to the electrical ground path of the luminaire to electrically couple the ground strap  108  to the electrical ground path. 
     As is shown in  FIG. 8 , the ground strap  108  extends through the body of the housing  102 , from one retaining member  110  to the other retaining member  110 . The grounds strap  108  is electrically coupled to the ground screw lug terminal  804 . In the example of  FIG. 8 , the ground screw lug terminal  804  is the center screw lug terminal  104 . In alternate embodiments, the ground screw lug terminal  804  can comprise any one of the screw lug terminal assemblies  104 , other than including the center terminal. 
     The ground strap  108  in  FIG. 8  includes a bent portion or connection point  806  that electrically engages the ground screw lug terminal  804 . The ground strap  108  is spaced apart from the other screw lug terminal assemblies  104  in a manner that prevents an electrical connection from being established. Thus, the ground strap  108  is configured to maintain electrical continuity only with the ground terminal of the terminal block assembly  100 , which in this example, is the center terminal  804  and is electrically isolated from the other screw lug assemblies  104 . 
     As noted above, in one embodiment, the stripped ends of the leads  504  can be inserted or pushed directly into the push-in terminals  106  without the need of tools or crimped connectors. As is illustrated in  FIG. 5 , a manufacturing lead release tool  510  can be used to depress the retention spring assembly  420  to release pressure on the manufacturing leads  504  and permit removal of the leads  504  from the push-in terminal assembly  106 . The manufacturing lead release tool  510  is inserted into a lead release opening  418 . The lead release tool  510  exerts pressure on the respective finger member  422  of retention spring assembly  420  which allows the lead  504  to be removed. 
       FIG. 11  illustrates one embodiment of a retention spring assembly  1120 . The retention spring assembly  1120  in this example is similar to the spring retention spring assembly  420  shown in  FIG. 4 . In this example, the finger member  1122  includes a retaining portion  1102  and a bent or angled portion  1104 . The retaining portion  1102  of the finger member  1122  will align with a respective lead opening  414  of the retention spring assembly  420 . The bent portion  1104  will generally align with a respective lead release opening  418 . In one embodiment, the bent portion  1104  is substantially parallel to the wall portion  1108  of the retention spring assembly  1120 . 
     In this example, the stripped end of the leads  504 , as was described above, will be retained between the blade portion  416  of the strain relief assembly  410  and the retaining portion  1102  of the finger member  1122 . The bent portion  1104  will provide a space between the finger member  1122  and the blade portion  416  of the strain relief assembly  410  when the finger member  1122  is pressed against the strain relief assembly  410 . 
     When the lead release tool  510  is inserted into the lead release opening  418 , the lead release tool  510  will engage the bent portion  1104  of the finger member  1122  and press the finger member  1122  away from the blade portion  416  of the strain relief assembly  410 . When the lead release tool  510  is removed from the lead release opening  418 , the space between the bent portion  1104  and the blade portion  416  will allow the tool  510  to be removed without catching on or otherwise engaging the retaining spring assembly  420 . 
       FIG. 12  illustrates an alternative embodiment of a terminal block assembly  1200  incorporating aspects of the present disclosure. In this example, the strain relief assembly or cap  1210  of the push-in terminal assembly  1206  is rotated approximately 90 degrees within the housing  1202  relative to the orientation of the strain relief cap  410  of  FIG. 1 . Thus, the alignment of the lead openings  1214  and lead release openings  1218  in each of the push-in terminal assemblies  1206  are arranged in an end to end configuration rather than the front to back configuration of the strain relief assemblies  410  shown in  FIG. 1 . 
       FIGS. 14-15  illustrate a component view of the strain relief cap  1210  and the retention spring assembly  1220  for the push-in terminal assembly  1206  of  FIG. 12 . In this example, the retention spring assembly  1220  comprises a two-piece assembly. As is shown in  FIGS. 14 and 15 , the retention spring assembly  1220  includes a finger member  1222  and a conductor member  1224 . The conductor member  1224  is configured to extend upward through the opening  1230  in the finger member  1222  when assembled. 
     Referring also to  FIG. 17 , the strain relief cap  1210  is configured to be disposed on top of the finger member  1222  and the conductor member  1224 . A top leg  1226  of the conductor member  1224  is received in a channel  1212  of the strain relief cap  1210 . The other leg  1228  of the conductor member  1224  is configured to engage a screw lug terminal  104 , in a manner as is generally described above with reference to screw lug terminals  104 . In this example, the leg  1228  is engaging the center ground terminal  804  and ground strap  108  as earlier described. 
     When the stripped end of a lead  504  is inserted into a lead hole  1214 , in this embodiment, the lead  504  will depress the finger portion  1222  of the retention spring assembly  1220  and be compressed between the finger portion  1222  and the conductor portion  1224 . The channel  1212  of the strain relief cap  1210  retains the conductor member  1224  in position within the opening  1240  for the strain relief cap  1210 . 
     Although the example of  FIGS. 4 and 14  illustrate the screw lug terminal assemblies and push-in terminal assemblies being inserted from the top of the terminal block housing, in one embodiment, the components could be inserted from the bottom of the terminal block housing. The bottom could then be capped, as opposed to inserting the components from the top and capping it from the top. 
     The aspects of the disclosed embodiments provide a terminal block assembly with screw lug terminals, push-in lead terminals and an integrated grounding strap. The terminal block of the disclosed embodiments permits stripped leads to be pushed directly into the push-in terminal without the need for tools or crimped connectors. As a result, the manufacturing process requires less labor and fewer components, resulting in overall lower total luminaire cost. 
     Thus, while there have been shown, described and pointed out, fundamental novel features of the invention as applied to the exemplary embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of devices and methods illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. Moreover, it is expressly intended that all combinations of those elements and/or method steps, which perform substantially the same function in substantially the same way to achieve the same results, are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.