Abstract:
A termination connector for a circuit breaker is disclosed. The termination connector preferably includes a plurality of single pole screw receiving members integrally attached by a molded housing for unitary attachment to a line or load end of a circuit breaker to assist in holding a nut or nut plate adjacent each screw hole in the circuit breaker&#39;s terminal straps. The molded housing preferably includes a line of perforations between each single pole screw receiving member so that the correct number of single pole screw receiving members can be retained and the others can be knocked off along the line of perforations. Provisions are disclosed for adaption of the connector to metric or English standard nut hardware. In addition, the termination connector and circuit breaker are provided with mating attachment devices for providing a simple yet secure connection.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to circuit breakers, and more particularly relates to a circuit breaker device which assists in installation. 
     During installation of a circuit breaker, terminal straps extending from either a line side or a load side of a circuit breaker must be connected to its source or load (such as to bus lines or cable lines). Connection may be accomplished by inserting a screw, or other rod-shaped connector, through a hole in the terminal strap and through an opening in a connector for the source or load. A nut, or equivalent receiving or tightening device, may then be attached to the screw for securing the connection between the terminal strap and the source or load. 
     When a screw is used to make the above-described connection, holding a nut for assembly of the load/source connector to the terminal strap is awkward and labor intensive. In some instances, holding the nut by hand is practically impossible and an alternative assembly method must be selected. 
     Threaded terminal straps are prone to being stripped if the proper screw is not used or if it is over-torqued. If they are stripped, then the entire circuit breaker may need to be replaced (at significant expense) or an alternate fastening method may be required. Furthermore, threaded terminal straps use threaded holes which do not allow for any misalignment of parts. 
     Individual terminal nut retainers exist which connect with a circuit breaker. These are somewhat inconvenient to use since each one needs to be connected individually. In addition, access to the terminals is limited since additional plastic is required to give each individual nut retainer the proper support. 
     SUMMARY OF THE INVENTION 
     In an exemplary embodiment of the invention, a multipole termination connector for holding a plurality of screw apertures adjacent a plurality of terminal straps extending from a circuit breaker is disclosed. The multipole termination connector comprises a molded housing, a plurality of single-pole screw accepting members, each screw accepting member having a molded portion integrally formed with the molded housing and a screw receiving portion located on the molded portion. An aperture in preferably provided in each screw receiving portion and an attachment device preferably extends from the molded housing and is adapted to attach the multipole termination connector to a circuit breaker. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a top perspective view of a circuit breaker for receiving the multipole termination connector of the present invention; 
     FIG. 2 shows a top perspective view of a multipole termination connector of the present invention; 
     FIG. 3 shows a top plan view of the multipole termination connector of FIG. 2; 
     FIG. 4 shows a bottom perspective view of the multipole termination connector of FIG. 2 before attachment to the circuit breaker of FIG. 1; 
     FIG. 5 shows a top plan view of a multipole termination connector of the present invention having four pole screw receiving members; 
     FIG. 6 shows a top plan view of the multipole termination connector of FIG. 5 with one screw receiving member removed; 
     FIG. 7 shows a right end view of the multipole termination connector of FIG. 5; 
     FIG. 8 shows a base side view of the multipole termination connector of FIG. 5; 
     FIG. 9 shows a connecting side view of the multipole termination connector of FIG. 5; 
     FIG. 10 shows a side cross-sectional view of a single pole screw receiving member of the multipole termination connector of FIG. 5; 
     FIG. 11 shows a top plan view of a circuit breaker load or line end with the terminal straps removed; 
     FIG. 12 shows a side cross-sectional view taken along line  12 — 12  of FIG. 11 with the multipole termination connector of FIG. 5 connected to the circuit breaker of FIG. 11; 
     FIG. 13 shows a top plan view of a screw accepting portion of a single pole screw receiving member for use with the multipole termination connector of FIG. 5; 
     FIG. 14 shows a top plan view of a screw accepting portion of a single pole screw receiving member for use with the multipole termination connector of FIG. 5; 
     FIG. 15 shows a partial and exaggerated top plan view of the opening of FIG. 14 before and after insertion of a nut therein; 
     FIG. 16 shows a side cross sectional view of the single pole screw receiving member of FIG. 13; 
     FIG. 17 shows a top plan view of a nut plate for use with the multipole termination connector of the present invention; and, 
     FIG. 18 shows a side cross-sectional view of the nut plate of FIG. 17 within a single pole screw receiving member for a multipole termination connector of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in FIG. 1, a multi-pole circuit breaker  10  is provided with a housing  12  including a top cover  14  through which an operating handle  16  may extend. The housing  12  may be made from molded plastic. Extending from line side end  22  and load side end  20 , is a plurality of upstanding walls  24 ,  26 , each extending from the housing  12  at an attached end  28  and to a free end  30 . The walls  24 ,  26  preferably extend substantially parallel to a sidewall  18  and substantially perpendicular to an end wall  19 . Exterior walls  24  extend substantially continuously from sidewalls  18  (only one sidewall  18  shown) while spacer walls  26  are provided at equal intervals between exterior walls  24  to divide the width w between the exterior walls  24  into three substantially equal segments. It should be noted that more spacer walls  26  could be used with a greater spacing between exterior walls  24  to create more segments for additional poles in the circuit breaker if desired. 
     The circuit breaker  10  shown in FIG. 1 is a three pole circuit breaker and is thus provided with three terminal straps  32  extending from the circuit breaker interior. Each terminal strap  32  is provided with a screw hole  34  for accepting a screw, or equivalent rod connector, to connect the terminal strap  32  with a connector end of a source or load (not shown). The screw hole  34 . in each terminal strap  32  may be oval shaped to allow for slight misalignment between the screw hole  34  and the screw hole of a nut or nut plate, which will be further described. 
     In order to secure the connection of the screw to the terminal strap  32  and associated source or load connector, a multipole terminal connector  40  may be used as shown in FIG.  2 . The multipole terminal connector z 40  includes a plurality of single-pole screw accepting members  42  extending from a molded housing  44 . The molded housing  44  is preferably molded from an insulative material such as plastic and includes a base portion  46  having a length l which is dimensionally as great or greater than the width w of the circuit breaker  10 . 
     Integral with the molded housing  44  are molded portions  48  of each screw accepting member  42 . The screw accepting members  42  further includes a screw receiving portion  50 . As shown in FIGS. 2 and 3, the screw receiving portion  50  may include a nut receiving plate  52  which may be integrally formed with the molded portion  48 . The nut receiving plate  52  includes an aperture  53  having a hexagonally shaped opening  54 . The opening  54  may have one or more longitudinal ribs or bumps  56  in its corner portions  55 . The bumps  56  provide the received nut  60  with a snug interference fit. The aperture  53  may further have a circular recess  58  below the hexagonally shaped opening  54  for receiving a stem of a screw (not shown). A platform  57  may be provided between the opening  54  and the recess  58  and for supporting the received nut  60 . 
     The screw receiving portion  50  includes a top surface  62  and a bottom surface (not shown), with the aperture  53  extending from the top surface  62  to the bottom surface. Below the bottom surface is an electrically insulative pocket  64 , a bottom portion of which is shown in FIG.  4 . The electrically insulative pocket  64  prevents a received screw stem from going to ground. 
     As further shown in FIG. 4, the molded housing  44  may include a plurality of apertures  66 , six in total, which surround the aperture  53  providing a substantially constant wall thickness of structural walls  68 . This arrangement saves on plastic material while providing the necessary structural rigidity and maintaining an aesthetically pleasing appearance. A line of perforations  82  preferably extends through the molded housing  44  between at least two adjacent single pole screw receiving members  42 . Thus, the multipole termination connector  40  may be molded as a unit with more than one pole where one of the poles may be broken off along the line of perforations  82  if it is not needed. For example, a four pole termination connector  40  as shown may have one of the poles broken away so that it can be used on the three pole circuit breaker  10 . This arrangement allows a single termination connector mold to make parts for multiple breaker configurations. Although only one line of perforations  82  is shown, it should be understood that a line of perforations  82  could be provided between each single pole screw receiving member  42 . Furthermore, although multipole termination connector  40  is shown with four poles, it is within the scope of this invention to mold the termination connector of the present invention with more or less poles. 
     Referring now to FIGS. 2 and 4, an attachment device for connecting the multipole terminal connector  40  to the circuit breaker  10  is shown. The attachment device may include a groove  70  and indent  72  on each side of each molded portion  48  for slidable and snap-fit engagment with a rib  74  and tab  76  protruding from each upstanding wall  24 ,  26 . Each wall  24 ,  26  may be provided with a ledge  78  for abutting engagement with a stop wall  80  formed on the molded housing  44  adjacent each molded portion  48 . When the multipole terminal connector  40  is to be attached to the circuit breaker  10 , one single pole screw receiving member  42  is aligned for each terminal strap and then slid in the direction indicated by arrow A with the groove  70  fitting over rib  74  until the tab  76  snaps into the indent  72  which corresponds to when the ledge  78  abuts with stop wall  80 . 
     Standard nuts for use with the present invention in its intended marketplace include both metric nuts and English nuts. One difference between a metric nut and an English nut is a slight difference in the dimension across the “flats”, that is, the distance from one hexagonal side of the nut to an opposite side of the nut. Also, the threading of an English nut and a metric nut may be slightly different. In one embodiment, the bumps  56  could be provided in each comer of the hexagonal shaped opening  54  to allow for an adjusted fit for either an English nut or a metric nut. 
     In another embodiment, as shown in FIG. 5, a multipole termination connector  90  may include a molded housing  92  having a plurality of single pole screw accepting members  94  extending therefrom. The screw accepting members include a molded portion  96  integral with the molded housing  92  and a screw receiving portion  98  having an aperture  100  therein. The aperture  100  is designed to accept either English standard nut hardware or metric standard nut hardware. The aperture  100  is formed from two overlapping hexagonal recesses to receive the standard nut hardware, where the two hexagonal recesses are rotated approximately 30-degrees from each other. The resultant aperture  100  thus includes a 24 sided opening. A first hexagonally shaped opening  102  is appropriately dimensioned to receive metric standard nut hardware, and the second hexagonally-shaped opening  104  is appropriately dimensioned to receive English standard nut hardware. One of the “points”  106  of either the metric or English hexagonal recesses  102 ,  104  is identified in the screw receiving portion  98  by alphanumeric character  108  identifying it as being the appropriate hexagonal recess for that particular standard nut hardware. For example, as shown in FIGS. 5 and 6, the letter “M” is used to identify the hexagonally shaped opening  102  as shaped to accept metric standard nut hardware. The other hexagonal recess  104 , 30-degrees rotated, would then be the appropriate hexagonal recess for the other standard nut hardware (in this case English). 
     As shown in FIGS. 8-9, the aperture  100  may further include a circular recess  110  below the  24  sided opening formed by hexagonal recesses  102 ,  104 . The circular recess  110  may receive a stem of a screw (not shown). A platform  112  may be provided between the opening  102 - 104  and the recess  110  for supporting a received nut (not shown). An electrically insulative pocket may be formed below the recess  110  for preventing the screw from going to ground. In some embodiments, where the screw may need to be attached by passing the stem through first the recess  110  and then the recesses  102 - 104 , such as when the multipole termination connector  90  is to be attached from the backside of the circuit breaker  130 , the recess  110  may pass all the way through the molded portion  96  rather than having a closed electrically insulative pocket. 
     As with multipole termination connector  40 , the multipole termination connector  90  may include at least one line of perforations  82  within the molded housing  92 . Thus, a four pole termination connector as shown in FIG. 5 could easily be converted to a three pole termination connector as shown in FIG. 6 by knocking off the leftmost single pole screw receiving member  94  along the line of perforations  82  which serves as a weakened connection area. 
     As further shown in FIGS. 5-6, an attachment device for connecting the multipole termination conlector  90  to the circuit breaker  130  (FIG. 11) is shown as including a dovetail projection  120  extending from the molded housing  92  between each single pole screw receiving member  94 . As shown in FIGS. 7-9, the dovetail projection  120  preferably extends the height h of the multipole termination connector  90 . As shown in FIG. 11, the circuit breaker  130  may be provided with a correspondingly shaped dovetail recess  132  within spacer walls  134  such that the dovetail projection  120  may be slidably received within dovetail recess  132 . 
     An additional attachment device for connecting the multipole termination connector  90  to the circuit breaker  130  is shown in FIGS. 5-10 as flange  140 . As most clearly shown in FIG. 10, flange  140  extends from the molded portion  96  at an attached end  142  to a free end  144 . The free end  144  is separated from the top of the molded portion  96  and adjacent the screw receiving portion  98  by a gap  146  which may be reduced when the free end  144  is pushed towards the screw receiving portion  98 . With reference to FIGS. 10-12, as multipole termination connector  90  is pushed into the circuit breaker  130  by sliding the dovetail projection  120  into dovetail recess  132 , the flange  140  abuts against the projection  150  extending from spacer walls  134  and compresses until the free end passes the projection  150 , at which point the flange  140  “snaps” back to its biased position shown in FIG.  10 . The multipole termination connector  90  is thus retained within the circuit breaker  130 . A support shelf  152  may be formed by projections extending from the spacer walls  134  to properly align the screw receiving portions  98  with the terminal straps (not shown) of the circuit breaker  130 . 
     Referring now to FIGS. 13 and 16, the aperture  100  may be provided with interference ribs  156  for providing a snug fit between the received nut and the aperture  100 . As a nut (not shown) is pressed into the aperture  100 , a portion of the rib or ribs  156  may be scraped off and forced downwardly. In order for the nut to maintain a proper fit against the platform  112 , the debris from the scraped off portions of rib or ribs  156  must be removed from the aperture  100 . As shown in FIG. 16, a clearance pocket  158  is provided directly below each rib  156  (where both rib  156  and clearance pocket  158  are exaggerated in size for clarity). Phantom line  156 ′ indicates where the rib  156  has been scraped off and its debris or scraped off portion has been deposited within the pocket  158 . 
     Referring to FIG. 14, one or more sawcuts  160  may extend from intersecting point s  162  between the hexagonally shaped opening  102  and hexagonally shaped opening  104 . As shown in FIG. 15, when a nut is pressed into the aperture  100 , the material, such as plastic, forming the connector  90  moves from the solid lines  164  to the dashed lines  166 , and closing the gap  168  formed by the sawcuts  160 . The sawcuts  160  thus provide a relief fit to a retained nut for preventing the material of the connector  90  from cracking. 
     Turning now to FIG. 17, a nut plate for use with a multipole terminal connector of the present invention comprises a metallic plate  170  having a threaded opening  172 . Separate nut plates could be provided for metric threads and English threads. The nut plates may then slide into grooves  174  in a single pole screw receiving member as previously described. Alternatively, the nut plates  170  could snap or press fit into a molded portion of a termination connector. The use of a nut plate  170  eliminates the need for separate standard nuts. In addition, the nut plate  170  could be provided with some leeway in movement to compensate for misalignment. 
     The multipole termination connectors of the present invention provides support for preventing terminal straps in circuit breakers from bending since the connector provides support under each strap. In addition the termination connector also provides structural support when installing cable or bus conductors and when torquing the terminal straps. Additionally, the mltipole termination connectors of the present invention provides support for the terminal straps under short circuit conditions where high magnetic forces are exerted between adjacent straps. 
     The termination connector of the present invention may be inserted from the bottom or top of the breaker. Additional variants would be to have clearance for connect on top and bottom. Clearance could either be variable or stopped by mechanical interference. 
     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.