Patent Document

BACKGROUND OF INVENTION  
         [0001]    A fuse holder includes a fuse carrier or fuse-carrier unit mounted within a receptacle or receptacle unit. In use, a fuse carrier bears an elongated fuse which has a pair of terminals. The fuse carrier releasably disposes the terminals for each fuse in tight electrical engagement with companion contacts of the receptacle.  
           [0002]    The fuse carrier commonly comprises a body of molded insulation and the receptacle has a base and a complementary cover, both of molded insulation. In use, fuse receptacles are fixed in place, as on a panel. The fuse carrier is pivotally joined to the receptacle.  
           [0003]    The pivotally joined carrier incorporates manual force-multiplied means for driving the fuse-carrier outward for releasing the tight grip of the contacts disposed within the receptacle on the fuse terminals. More specifically, the force-multiplying means in the described fuse holder is a lever pivotally disposed at one end of the fuse holder and acting against the other end of the fuse holder. The fuse terminals are forcibly released generally concurrently from the receptacle contacts. Once the carrier is pivoted outward, the fuse may be removed and replaced. Typically, each fuse holder contains one fuse, being a single-pole device for interrupting a single current path. A common form of circuit connection to the receptacle contacts of a fuse holder is by wires that enter the receptacle, joined to the receptacle contacts by screw-actuated wire fasteners.  
           [0004]    Presently, different current rated fuses have different diameters and lengths necessitating varying fuse carriers, thus requiring variably configured fuse carriers for each different fuse. In addition, the variably configured fuse carriers necessitate variably configured housings for each different fuse carrier. Thus, the costs associated with tooling, manufacture and inventory of different housings for different fuse carriers is increased.  
         SUMMARY OF INVENTION  
         [0005]    The above discussed and other drawbacks and deficiencies are overcome or alleviated by a fuse holder comprising: a fuse having a pair of fuse terminals; a housing configured to accept any fuse carrier selected from a plurality of fuse carriers, the housing defining an enclosed region adapted to accept the fuse; a pair of contacts within the housing at opposite ends of the enclosed region and configured to engage the fuse terminals; and a fuse carrier selected from the plurality of fuse carriers, the fuse carrier configured to support the fuse and position the fuse terminals in the enclosed region in electrical engagement with the pair of contacts.  
           [0006]    In an alternative embodiment, a method of assembling a fuse holder comprising a housing having a cavity therein for supporting a fuse carrier is also disclosed, the method comprising: selecting a fuse carrier from a plurality of fuse carriers, each fuse carrier of the plurality of fuse carriers configured to support a different fuse size, the selecting being based on a desired current rating for a fuse to be fitted within the housing; configuring the fuse carrier to accept and position the fuse for engagement with contacts disposed within the housing; configuring the cavity to accept the plurality of fuse carriers; and installing the selected fuse carrier in the housing. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0007]    Referring now to the drawings wherein like elements are numbered alike in the several Figures:  
         [0008]    [0008]FIG. 1 is a perspective view of an assembled single pole fuse holder;  
         [0009]    [0009]FIG. 2 is a perspective view of an assembled single pole fuse holder having a neutral connector;  
         [0010]    [0010]FIG. 3 is a perspective view of the fuse holder of FIG. 1 without a cover;  
         [0011]    [0011]FIG. 4 is a perspective view of a fuse carrier and fuse removed from a fuse holder;  
         [0012]    [0012]FIG. 5 is a perspective view of the fuse holder in FIG. 3 having a different fuse carrier configured with a shorter fuse;  
         [0013]    [0013]FIG. 6 is a partially exploded view of the fuse holder shown in FIG. 2;  
         [0014]    [0014]FIG. 7 is a perspective view of an exemplary cage holder used in the fuse holder shown in FIGS. 1 and 3;  
         [0015]    [0015]FIG. 8 is a perspective view of another exemplary cage holder used in the fuse holder shown in FIGS. 2 and 6;  
         [0016]    [0016]FIG. 9 is a perspective of a fuse holder shown in FIGS. 2 and 6 in an open position detailing a neutral connection;  
         [0017]    [0017]FIG. 10 is a table listing the fuse carrier types and corresponding fuse for each fuse carrier type;  
         [0018]    FIGS.  11 - 16  illustrate each fuse carrier type with a corresponding fuse listed in FIG. 10; and  
         [0019]    [0019]FIG. 17 is a schematic view of an electrical enclosure including a single pole fuse holder and a single pole fuse holder with a neutral connection. 
     
    
     DETAILED DESCRIPTION  
       [0020]    Referring to FIGS. 1 and 2, there is shown a fuse holder  24  including a housing  26  and a fuse carrier  28 . Housing  26  includes a base  54  and a cover  56  that are adapted to retain a single pole cage holder  50  (FIG. 1) or a two-pole cage holder  52  (FIG. 2). In FIG. 1, housing  26  retains a cage holder  50  that has a single terminal  25  for accepting a wire (not shown) from a phase of a power distribution circuit (not shown). FIG. 2 depicts housing  26  retaining a cage holder  52  having a phase terminal  25  and a neutral terminal  27 . Terminal  25  accepts a wire (not shown) from a phase of a power distribution circuit (not shown) and the terminal  27  accepts a neutral wire from the power distribution circuit.  
         [0021]    Base  54  and cover  56  of housing  26  define an enclosed region  29  therebetween and an opening  30  to region  29  in a side extension  32  of housing  26 . Fuse carrier  28  is pivotally mounted on housing  26  and is movable between a closed position (shown in FIGS. 1 and 2), and an open position (FIG. 9), in which a fuse can be inserted into carrier  28 . Fuse carrier  28  includes a lever  34  for pivotally opening and closing carrier  28  relative to housing  26 . A circuit indicator tag  36  is optionally disposed on lever  34  to identify the fuse rating of a fuse enclosed within housing  26 . On a top surface  40  of housing  26  are two apertures  42 ,  44  which allow a portion of cage holder  50 , or  52  to extend therethrough. Housing  26  also includes a first opening  46  and a second opening  48  disposed at opposite ends of fuse holder  24  and extending in planes generally perpendicularly oriented relative to top surface  40 . A portion of cage holder  50  or  52  extends through first and second openings  46  and  48 .  
         [0022]    Referring to FIG. 3, fuse holder  24  is shown absent cover  56 . Within enclosed region  29  of housing  26  are a pair of U-shaped contacts  64 ,  66  at opposite ends of the enclosed region  29  and spaced to engage end cap terminals  72 ,  74  on the ends of a fuse  80  when fuse  80  is moved within enclosed region  29 . Fuse carrier  28  is pivotally mounted on housing  26  via a pin (not shown) extending through an aperture  82  formed in fuse carrier  28 . Fuse carrier  28  is movable between a closed position (shown in FIG. 3), in which contacts  64 ,  66  electrically engage end cap terminals  72 ,  74 . Contacts  64 ,  66  are connected to terminals  68 ,  70 , respectively. Terminals  68 ,  70  are in turn received within cage holders  50  and are in electrical communication with electrical wires  71 , which are also received within cage holders  50 .  
         [0023]    Referring to FIG. 4, fuse carrier  28  defines fuse insertion region  88 . Fuse carrier  28  further includes an aperture  90  configured to slidably receive end cap terminal  74  when fuse  80  is inserted in fuse insertion region  88 . Fuse carrier  28  has shoulders  92 ,  94  at the lower end of region  88  to prevent further translation of fuse  80  through aperture  90 . The outside diameter of end cap terminal  74  rests against shoulders  92 ,  94 . As is best shown with reference to FIGS. 3 and 4, end cap terminal  72  fits within the other end of fuse insertion region  88  to allow fuse carrier  28  to pivot to a closed position without having end cap terminal  72  contacting side extension  32  that forms opening  30  (FIG. 3). Opening  30  to housing  26  is sized to permit closure of carrier  28  with fuse  80  carried therein.  
         [0024]    Referring to FIG. 5, fuse holder  24  shown in FIG. 3 includes an alternative fuse carrier  28  for holding a shorter fuse  80 . Shoulder  94  is disposed on fuse carrier  28  such that when fuse carrier  28  is in the closed position, terminal  64  is aligned with end cap terminal  72  of fuse  80 . Since fuse  80  is shorter in FIG. 5 than in FIG. 3, terminal  66  of FIG. 3 is not long enough to electrically connect to end cap terminal  74  of shorter fuse  80 . An alternative contact  166  is used to make an electrical connection with end cap terminal  74 . Contact  166  is generally C-shaped, and electrical contact is made between an outside surface  168  defining the C shape, end cap terminal  74 , and terminal  70 . Shoulder  94  prevents further translation of fuse  80  to the left. An end stop  93  disposed in a recess  97  formed in base  54  to receive end stop  93  prevents a bias of contact  166  from translating fuse  80  to the right as shown in FIG. 5. End stop  93  also guides fuse  80  into electrical communication with contacts  64 ,  66 ,  166  by positioning fuse  80  intermediate contacts  64 ,  66 ,  166  as fuse carrier  28  and fuse  80  are pivotally moved into enclosed region  29 .  
         [0025]    Referring to FIG. 6, an exploded view of fuse holder  24  with two pole cage holders  52  is illustrated. Cover  56  and base  54  are separated to reveal the interaction of fuse carrier  28  with cage holder  52 . Cover  56  and base  54  are configured to form a first cavity  96  and a second cavity  98 . Cavities  96 ,  98  are disposed at opposite ends of region  29 , and each cavity  96 ,  98  is configured to receive either cage holder  50  or cage holder  52 . In this manner, the same cover  56  and base  54  can be used for different cage holders  50 ,  52 . Two inside edges  97  depending from housing  26  and disposed in region  29  define cavities  96 ,  98 . Each edge  97  has slots  99  formed therein to receive terminals  68 ,  70  and allow electrical communication between single pole terminal  25  and neutral connection terminal  27  within cage holder  52  disposed at either end of fuse holder  24 .  
         [0026]    Referring to FIG. 7, cage holder  50  for use with a single pole without a neutral connection is illustrated. Cage holder  50  comprises a first half section  100  and a complementary second half section  102 . Both sections  100 ,  102  are configured to receivably retain a cage  104  within an interior portion  106  of cage holder  50 . Cage  104  is stamped from an electrically conductive material, such as copper, aluminum, or the like. Cage  104  includes a flange  108  extending generally perpendicular from a bottom side  110  of cage  104 . Flange  108  prevents rotation of cage  104  when cage  104  is disposed within interior portion  106  of cage holder  50 . More specifically, flange  108  extends through a forward facing slot  111  formed in a bottom surface  113  of cage holder  50 . In this way, bottom side  110  of cage  104  rests on bottom surface  113  of cage holder  50 . Cage  104  further includes a threaded opening  112  at a top side  114  for threadably receiving a screw  116 . An electrical wire (i.e., wire  71  in FIG. 3) is received in an enclosed area  118  defined by cage  104  and retained therein when screw  116  is tightened against terminals  68 ,  70  extending in cage  104  to retain wire  71  by clamping wire  71  between terminal  68 ,  70  and bottom side  110  of cage  104 .  
         [0027]    Referring to FIGS. 6 and 7, cage holder  50  includes a top surface  120  configured to fit within edges  121  defining apertures  42 ,  44 . Top surface  120  includes an opening for access to screw  116  for operatively turning screw  116  with a tool, such as a screwdriver. Cage holder  50  further comprises a front face  122  configured to fill openings  46 ,  48 , while providing a generally flush surface mount between housing  26  and front face  122 . Front face  122  includes a cutout  124  aligned with enclosed area  118  of cage  104  to allow connection of wire  71  with cage  104 .  
         [0028]    Referring to FIG. 8, cage holder  52  for use with a single pole including a neutral connection is illustrated. Cage holder  52  has a front face  130 , a rear face  132  and a dividing face  134  disposed intermediate faces  130 ,  132  and generally extending perpendicularly therebetween. Dividing face  134  and front and rear faces  130 ,  132  define a first cavity  136  and a second cavity  138  within cage holder  52 . One cage  104  is received in cavity  136  for a neutral connection by disposing cage  104  in between front face  130  and rear face  132  from a first side  140  of cage holder  52 . A slot  141  is disposed on rear face  132  and aligned with one cage  104  to provide access for a neutral strap terminal (not shown) to one cage  104 . Another cage  104  is received between front face  130  and rear face  132  from a second side  142  of cage holder  52 . Another slot  141  (shown in phantom) is disposed on rear face  132  and aligned with cage  104  in cavity  138  to provide access for terminals  68 ,  70 . Front face  130  includes a cutout  144  aligned with one cage  104  received in first cavity  136  and a cutout  146  aligned with another cage  104  received in second cavity  138 .  
         [0029]    Referring to FIGS. 6 and 8, cage holder  52  further comprises a top surface  148  configured to fit within edges  121  defining apertures  42 ,  44  formed in housing  26 . Top surface  148  is configured to divide each aperture  42 ,  44  to provide two openings in each aperture  42 ,  44  coinciding with cavities  136 ,  138  to allow access to screw  116  of each cage  104  disposed in each cavity  136 ,  138 . Likewise, front face  130  is defined by a front face edge  149  configured to fit within edges  123  defining openings  46 ,  48 . Front face edge  149  offers a generally flush surface mount between housing  26  and front face  130 .  
         [0030]    Referring to FIGS. 6 and 9, a description of fuse holder  24  having neutral connection terminal  27  follows. Neutral connection terminal  27  includes a pair of neutral straps  150  disposed between two pairs of raised ribs  152  configured in base  54 . An angled block  154  is disposed intermediate straps  150  separating one pair of raised ribs  152  from the other pair of ribs  152 . Block  154  is biased towards opening  30  by a spring  156  and is guided by ribs  152 . One end of spring  156  depends from base  54  while another end of spring  156  depends from a bottom surface of block  154 . Block  154  includes a conducting plate  158  positioned to provide electrical connection between neutral straps  150  when block  154  is moved towards opening  30 . Each neutral strap  150  includes a protrusion  160  pointing downward towards conducting plate  158  to make the electrical connection between neutral straps  150  and plate  158 .  
         [0031]    [0031]FIG. 9 illustrates fuse holder  24  with block  154  in the open position, thus breaking the electrical connection between neutral straps  150 . When fuse carrier  28  is pivoted about aperture  82  in a counterclockwise direction, an arm  161  depending from fuse carrier  28  contacts an angled surfacer  62  of angled block  154 . Further counterclockwise pivoting of fuse carrier  28  forces the block  154  downward, thereby breaking the electrical connection between a top surface of plate  158  and protrusions  160 . When fuse carrier  28  is fully opened as shown in FIG. 9, arm  161  contacts a top surface  164  of bock  154  biasing block  154  downward against the bias of spring  156 . It will be appreciated that arm  161  is configured to break the neutral circuit before the circuit carrying fuse  80  is broken when opening fuse carrier  28  from a closed position.  
         [0032]    To close fuse carrier  28  with fuse  80  inserted therein, fuse carrier  28  is pivoted clockwise about a pin (not shown) inserted in aperture  82 . When fuse carrier  28  is pivoted in a clockwise direction, arm  161  is tapered to allow block  154  to move upward under action of spring  156  as arm  161  is pivoted away to the left limiting contact with block  154 . Further clockwise pivoting of fuse carrier  28  allows block  154  to translate upward, thereby making the electrical connection between top surface of plate  158  and protrusions  160 . When fuse carrier  28  is fully closed as shown in FIG. 6, arm  161  no longer contacts top surface  164  of bock  154  biasing block  154  downward against the bias of spring  156  and fuse  80  is electrically connected with contacts  64 ,  66 .  
         [0033]    Turning to FIG. 10, a table  200  illustrates six different fuse carrier types  204  that can be inserted within housing  26 . A first column  202  lists a carrier type  204  (i.e., one through six). A second column  206  adjacent to first column  202  lists a fuse type  208  that is utilized in a carrier type  204 . For example, if “Carrier Type 2” is selected from first column  202 , a corresponding fuse type  208  in column  206  indicates that a NFC  210  and a BS  212  type fuse may be utilized in carrier type 2. “NFC” is a French standard for fuses and “BS” is a British standard for fuses. Table  200  shows a total of seven different fuse types  208  for use with six different fuse carriers  28 . Each different fuse carrier  28  can be installed in an identical housing  26 . A third column  214  lists the ampere ratings for fuses  80  that correspond with a selected fuse carrier type  204 , and vice versa. Columns  216 ,  218 , and  220  list fuse  80  dimensions corresponding to fuse length, fuse diameter, and fuse end cap terminal length, respectively, for a particular fuse  80  that can be utilized with a selected fuse carrier type  202 . Table  200  is provided as an example and is not to be construed as exhaustive, as it will be appreciated that other fuse carriers are optionally configured to accept differently dimensioned fuses for use with the same housing  26 .  
         [0034]    Referring to FIGS.  11 - 16 , a fuse carrier  28  representing each of the fuse carrier types  204  (i.e., 1-6) listed in table  200  are illustrated having fuse  80  of the corresponding fuse type  208  inserted therein. Each fuse carrier  28  in FIGS.  11 - 16  is configured to receive a corresponding fuse  80  and position fuse  80  in electrical communication with contacts  64  and  66  (FIG. 3) or  166  (FIG. 5) when fuse carrier  28  is inserted in housing  26  (FIGS. 3 and 5) and is pivoted about a pin disposed in aperture  82  to a closed position. Each fuse carrier  28  is configured to receive a particular fuse having specific dimensions. However, each fuse carrier  28  in FIGS.  11 - 16  is configured such that each carrier  28  may be inserted in a housing that is configured to be utilized with any one fuse carrier  28  in FIGS.  11 - 16 . Since housing  26  has a single configuration adapted to accept each fuse carrier  28  in FIGS.  11 - 16 , a separate base  54  and cover  56  are not necessary for each fuse type  208  having different dimensions utilized in fuse holder  24 .  
         [0035]    The fuse holder  24  provides the flexibility of achieving a fuse holder for different fuses having different dimensions utilizing the same base and cover, while only changing the fuse carriers that support the different fuses. By using the same base and cover for housing different fuse carriers supporting variably dimensioned fuses, costs associated with tooling and inventory are reduced. It will be appreciated that the present disclosure is not limited to single pole fuse holders and may be utilized with multiple pole fuse holders.  
         [0036]    Referring to FIG. 17, a schematic diagram illustrates a fuse system for fuse protection to a distribution circuit in an electrical enclosure  300 . Electrical enclosure  300  optionally includes a panel board. Electrical enclosure  300  receives electrical power from electrical wire  71  that is electrically connected to terminal  25  within cage holder  50  (shown in phantom lines) at one end of each fuse holder  24  attached to enclosure  300 . Another terminal  25  at an opposite end of each fuse holder  24  is connected to wire  71  that provides a path for electrical current to a protected circuit (not shown). The lower mounted fuse holder  24  shown in FIG. 17 includes a neutral line  302  received in neutral terminal  27  within cage holder  52  (shown in phantom) at one end of fuse holder  24 . Neutral line  302  exits fuse holder  24  from another neutral terminal  27  disposed in cage holder  52  at an opposite end of fuse holder  24  and provides a neutral line connection for a protected circuit (not shown).  
         [0037]    While the invention has been described with reference to an exemplary 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.

Technology Category: 5