Pullout fuse holder
FIELD OF THE INVENTION 
     This invention relates in general to pullout fuse holders and more particularly to an improved and more economical pullout fuse holder of the type adapted to interconnect a respective bus bar and load. 
     SUMMARY OF THE PRIOR ART 
     Pullout fuse holders usually include a base or holder carrying line and load terminals and receiving a cover carrying fuses. A pair of cover terminals detachably connected to each end of a respective fuse are adapted to connect to the base line and load terminals in response to insertion or assembly of the cover to the base. If it is desired to disconnect the lines from the load the cover is removed to disconnect the cover terminals from the line and load terminals. 
     A problem is then presented in storing the cover and fuses especially in industrial environments and since the base line terminal is then also exposed, a hazard exists, unless covered. 
     One advantageous solution to this problem is shown in U.S. Pat. No. 3,202,788, where the cover and base terminals are asymmetrically arranged relative to the cover and base respectively so that the cover in one orientation connects the fuses on assembly to the base and in another orientation misaligns the cover and base terminals to prevent the completion of a circuit therebetween. This arrangement while effective requires more material than desired in order to provide the asymmetrical arrangement of the parts. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a pullout fuse holder comprising a base and cover with the cover carrying a plurality of symmetrically arranged fuses, each having symetrically arranged identical terminals. 
     The cover is adapted to be received in a base having symmetrically positioned identical female line side and load side terminals for each fuse with the line side terminals adapted to be connected to respective bus bars. The bus bars are of rectangular cross-section arranged in a stacked array with spaced flat surfaces adapted to be engaged by jaws secured to the line side terminals and are of the type sold by the Square D Company under the trademark I-LINE busway. 
     A plurality of asymmetrically arranged stops are provided on the cover and a plurality of asymmetrically arranged stops are provided on the base. Therefore when the cover is assembled to the base in one orientation the symmetrically positioned terminals carried by the cover extend a connection through the respective fuses carried by the cover and if assembled to the base in another orientation, the stops engage to prevent engagement between the cover terminals and the holder terminals. Suitable indicia on the cover and holder indicate the connected or stored condition respectively of the fuses. 
     Thus the cover may be conveniently stored in the base and prevent inadvertent contact with the base terminals, while the male and female terminals may be of respective identical construction and symmetrically positioned relative each other. 
     It is therefore one object of the present invention to provide an improved pullout fuse holder containing means for conveniently and economically storing fuses in an associated base. 
     It is another object of the present invention to provide a more economical pullout fuse holder capable of retaining a cover in either a fuse connecting or fuse disconnecting position and for providing clear indicia of each condition. 
     Other objects of this invention will become apparent on examination of the following specification together with the claims and the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a pullout fuse holder incorporating the principles of the present invention. 
     FIG. 2 is a top elevational view of the fuse holder shown in FIG. 1. 
     FIG. 3 is a sectional view taken through the line 3--3 in FIG. 1. 
     FIG. 4 is a top elevational view of the base. 
     FIG. 5 is a sectional view taken through the line 5--5 in FIG. 3; and 
     FIG. 6 is a sectional view similar to FIG. 3, but showing the cover and fuses in stored condition. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIGS. 1 and 2 a pullout fuse holder or box is indicated by the reference character 10. The fuse holder comprises a housing or base 12 having a cover 14 carrying a plurality of spaced parallel cartridge type fuses 16. 
     The base 12 includes a bottom wall 20 having longitudinally extending spaced side walls 22 and spaced end walls 24 and 26 defining a perimeter wall for an opening or recess 28 of the base in which the cover 14 is received as best seen in FIGS. 3-6. 
     The wall 20 is provided with a plurality of spaced steps 30 adjacent wall 24 and a passage 32 in each step enables an L-shaped blade or male terminal 34 connected to a respective fuse flip 36 to engage between the spring fingers of female line side terminal or terminal means 38. Terminal 38 is connected to a respective bus bar terminal 40 and each is secured in common to a shelf wall 42. Terminal 40 has a pair of jaws 43 at the end opposite terminal 38 and the jaws project into a respective one of vertically spaced passageways 44, 44a, and 44b, for example, formed in a shroud 46. 
     Shroud 46 is secured to the corresponding end of base 12 and each passageway 44, etc. receives a respective one of a plurality of vertically stacked bus bars indicated by dashed lines 48 to enable the respective jaws 43 to connect thereto and receive incoming or line current of a respective phase. In addition an adapter 50 is secured to a depending portion of wall 20 adjacent the end of base 12 opposite shroud 46 and may serve to anchor the opposite end of the fuse holder. The jaws, adapter and shroud are similar to corresponding apparatus disclosed in U.S. Pat. Nos. 3,346,777, 3,588,619 and 3,842,322. 
     The fuse clip 36 together with terminal 34 are secured to the lower surface of cover 14 adjacent one end of the cover and the clip conventionally connects and secures one terminal of a respective cartridge fuse 16. The other terminal of the respective cartridge fuse 16 is connected and secured in a fuse clip 52 to suspend the respective fuse from the cover. A blade or male terminal 54 identical to terminal 34 and extending from the fuse clip 52 engages between spring fingers of a female load side terminal or terminal means 56 identical to terminal 38 to connect each fuse to a respective load terminal 58. The blade receiving end of terminal 56 is seated in a well or recess formed in the bottom wall 20 for engagement with terminal 54 and a shank portion thereof extends through a respective passage in end wall 26 for securement with the respective load terminal 58 to a shelf wall 60. Partition walls 62 extend between the respective load terminals 58 to minimize electrical leakage and the chance of inadvertent contact therewith. 
     As best seen in FIGS. 3, 5 and 6 the cover has a top wall 64 spanning the opening 28 to bottom on the top edge of base 12 with a handle 66 projecting upwardly therefrom. Indicia 68 and 70 reading ON and OFF respectively are formed on the upper surface of the cover adjacent a respective longitudinal end of the cover. The cover 14 also is provided with respective end walls 72 and 74 adjacent the respective indicia and longitudinally extending side walls 76 forming a perimeter wall adapted to be received in recess 28 in response to movement along the axis of the housing perimeter wall. 
     End wall 72 overlaps a portion of each blade 34, while wall 74 overlaps a portion of each blade 54. A spring detent 78 is secured in a recess of the shroud and projects through wall 24 to provide a retention force for the cover. Wall 74 is also provided with spaced projections or stop walls 80 best seen in FIG. 6 and projecting therefrom beneath a rim portion of cover wall 64. Walls 80 are engaged in the passage portion of wall 26 when the cover is arranged as shown in FIG. 3 in one orientation to align and engage each terminal 34 and 54 with a respective one of terminals 38 and 56 and the cover side walls 76 and end walls 72 and 74 with a respective housing side wall 22 and end walls 24 and 26 when the cover is in ON position. At that time the arrow indicated at indicia 82 on the top surface of holder 10 is directly adjacent the indicia ON of the cover 14 and the blade terminals 34 and 54 engage terminals 38 and 56 respectively to enable completion of a circuit from the bus bars 48 to respective load terminals 58. 
     In addition to the stop walls 80, a plurality of spaced partition walls 82 and 84 located between the fuses depend from the cover 14 and extend inwardly toward each other from walls 72 and 74 respectively. The walls 82 and 84 extend a respective preselected distance from the respective wall 72 or 74 into the recess 28. Each wall 82 is received in a respective recess 86 and each wall 84 is received in a respective recess 88 formed in the bottom wall 20 of the base 12. The walls 82 and 84 shield the fuse terminals from each other. Each recess receives a respective partition wall 82 and 84 to a depth sufficient to enable the terminals 34 and 54 to engage terminals 38 and 56 respectively when the cover 14 is in the ON position as shown in FIGS. 3 and 5 for example. Guide walls 90 are formed on wall 20 along each longitudinal edge of each recess 86. 
     When however it is desired to disconnect the circuits extending between terminals 38 and 56, the cover 14 is simply lifted and rotated 180° about the vertical axis along which the cover and housing move relative each other to align the indicia OFF on the cover 14 adjacent the arrow 82 and the cover reinserted into the opening 28. As neither the wall 24 or shroud 46 have passages to receive the stop walls 80, the stop walls 80 engage the top surface of the shroud as seen in FIG. 6 before the blade terminals 34 and 54 can engage the terminals 38 and 56 despite the alignment of terminal 34 with terminal 56 and terminal 54 with terminal 38. Substantially simultaneously lugs or stops 92 projecting upwardly from the bottom wall 20 in alignment with respective walls 82 and 84 engage the bottom stop edges of walls 82 as these walls extend into recess 28, a greater distance than walls 84. The fuses 16 are thus disconnected from the respective bus bars and stored in the housing with the stored condition clearly indicated by the alignment of indicia OFF with the arrow 82. It will be noted that the spring 78 engages in a recess of the cover side wall 74 to hold the cover assembled to the base 12. 
     It will be appreciated that the semi-circular spring type fuse clips 36 and 52 may be replaced by fuse clips of the type adapted to receive blade-like or knife-type terminals on the fuse ends. 
     The foregoing is a description of an improved pullout fuse holder whose inventive concepts are believed set forth in the accompanying claims. PG,8