Patent Publication Number: US-2023162940-A1

Title: Fuse module with clamped fuse installation

Description:
FIELD OF THE DISCLOSURE 
     The disclosure relates generally to the field of circuit protection devices and relates more particularly to a fuse module with fuses that can be easily clamped and unclamped for convenient installation and removal. 
     BACKGROUND OF THE DISCLOSURE 
     In the global automotive market there has been a trend toward implementing so-called “pre-fuse boxes” that are disposed within automobile engine compartments and connected to automobile battery terminals. The primary purpose of a pre-fuse box in an automobile is to prevent electrical damage to the automobile battery and connected loads that may otherwise result from short-circuiting in high-current-conducting wires, such as may occur in the event of a collision. 
     Existing pre-fuse boxes are typically quite large and require a great deal of space within an automobile engine compartment where space is already very limited. Additionally, fuses within existing pre-fuse boxes are typically secured using conventional mechanical fasteners (e.g., nuts, bolts, etc.) which contribute to the size of a pre-fuse box and can make the installation and removal of fuses cumbersome and time-consuming. 
     It is with respect to these and other considerations that the present improvements may be useful. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter. 
     A fuse module in accordance with an exemplary embodiment of the present disclosure may include a housing formed of an electrically insulating material, a busbar disposed within the housing adjacent an interior surface of a rear wall of the housing, a terminal extending through a front wall of the housing, the terminal having a fuse coupling portion disposed within the housing adjacent an interior surface of a front wall of the housing and a conductor coupling portion protruding from an exterior surface of the front wall of the housing, and a movable pushrod extending through the rear wall of the housing and having a head portion disposed adjacent a rigid portion of the busbar for moving the rigid portion of the busbar between a retracted position, wherein the rigid portion of the busbar is located near the interior surface of the rear wall, and an extended position wherein the rigid portion of the busbar is located further from the interior surface of the rear wall relative to the retracted position. 
     A fuse module in accordance with another exemplary embodiment of the present disclosure may include a housing formed of an electrically insulating material, a busbar disposed within the housing adjacent an interior surface of a rear wall of the housing, a terminal extending through a front wall of the housing, the terminal having a fuse coupling portion disposed within the housing adjacent an interior surface of a front wall of the housing and a conductor coupling portion protruding from an exterior surface of the front wall of the housing, and a fuse disposed within the housing, The fuse may include a mounting block formed of an electrically insulating material, and a fuse plate having a rear portion disposed on a rear surface of the mounting block, in a confronting relationship with the rigid portion of the busbar, a front portion disposed on a front surface of the mounting block, in a confronting relationship with fuse coupling portion of the terminal, and a fusible element disposed adjacent a top surface of the mounting block and connecting the rear portion of the fuse plate to the front portion of the fuse plate. The fuse module may further include a movable pushrod extending through the rear wall of the housing and having a head portion disposed adjacent a rigid portion of the busbar for moving the rigid portion of the busbar between a retracted position, wherein the rigid portion of the busbar does not engage the rear portion of the fuse plate, and an extended position wherein the rigid portion of the busbar engages the rear portion of the fuse plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  is a perspective view illustrating a fuse module in accordance with an exemplary embodiment of the present disclosure; 
         FIG.  1 B  is a top view illustrating the fuse module shown in  FIG.  1 A ; 
         FIGS.  2 A- 2 C  are a series of perspective views illustrating a fuse of the fuse module shown in  FIGS.  1 A and  1 B ; 
         FIGS.  3 A and  3 B  are top views illustrating fuses and a busbar of the fuse module shown in  FIGS.  1 A and  1 B ; 
         FIGS.  4 A and  4 B  are detail views illustrating a pushrod and a surrounding portion of a rear wall of a housing of the fuse module shown in  FIGS.  1 A and  1 B ; 
         FIGS.  5 A- 5 D  are a series of cross-sectional views illustrating a fuse of the fuse module shown in  FIGS.  1 A and  1 B  being installed and removed; 
         FIG.  6    is a perspective view illustrating an exemplary implementation of the fuse module shown in  FIGS.  1 A and  1 B . 
     
    
    
     DETAILED DESCRIPTION 
     A fuse module in accordance with the present disclosure will now be described more fully with reference to the accompanying drawings, in which preferred embodiments of the fuse module are presented. It will be understood, however, that the fuse module may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will convey certain exemplary aspects of the fuse module to those skilled in the art. 
     Referring to  FIGS.  1 A and  1 B , a perspective view and a top view illustrating a fuse module  10  in accordance with an exemplary, non-limiting embodiment of the present disclosure are shown. For the sake of convenience and clarity, terms such as “front,” “rear,” “top,” “bottom,” “side,” “above,” and “below” may be used herein to describe the relative placement and orientation of various components of the fuse module  10 , all with respect to the geometry and orientation of the fuse module  10  as it appears in  FIGS.  1 A and  1 B . Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
     The fuse module  10  may generally include an electrically insulating housing  12 , an electrically conductive busbar  14  disposed within the housing  12  adjacent a rear wall  15  of the housing  12 , a plurality of electrically conductive terminals  16  extending through a front wall  17  of the housing  12 , a plurality of fuses  18  disposed within the housing  12  between busbar  14  and respective terminals  16 , and a plurality of pushrods  20  extending through the rear wall  15  of the housing  12 . Each of the terminals  16  may include a conductor coupling portion  16   a  disposed on a shelf or flange  25  projecting from an exterior surface of the front wall  17  of the housing  12 , and a fuse coupling portion  16   b  disposed within the housing  12  immediately adjacent, and flatly abutting, an interior surface of the front wall  17 . Threaded mounting posts  19  may extend from the flange  25  through each of the conductor coupling portions  16   a  for facilitating connections to electrical conductors as further described below. The terminals  16  may be generally L-shaped (when viewed from the side) so that conductor coupling portion  16   a  and fuse coupling portion  16   b  of each terminal  16  are oriented perpendicular to one another. The present disclosure is not limited in this regard. The fuse module  10  may further include a cover (not shown) that may be removably coupled to the open top of the housing  12  for protecting components of the fuse module  10  from external elements. Notably, the term “fuse module” as used herein may refer to embodiments of the present disclosure with or without any fuses  18  disposed within the housing  12  between the busbar  14  and the terminals  16 . That is, all of the fuses  18  may be removed from the housing  12 , and the remaining structure may still be referred to as a “fuse module.” 
     Referring to  FIGS.  2 A- 2 C , several views illustrating one of the fuses  18  and its components are shown. It will be understood that all of the fuses  18  shown in  FIGS.  1 A and  1 B  are substantially identical to the fuse  18  shown in  FIGS.  2 A- 2 C , and that the illustrations of the fuse  18  provided in  FIGS.  2 A- 2 C , and the corresponding description of the fuse  18  provided below, shall apply to all of the fuses  18  shown in  FIGS.  1 A and  1 B . 
     In various embodiments the fuse  18  may be, or may be similar to, a commercially available fuse manufactured by LITTELFUSE, INC and sold under the name ZCASE. The present disclosure is not limited in this regard. The fuse  18  may include a mounting block  27  formed of an electrically insulating material, and an electrically conductive fuse plate  22  that extends around several surfaces of the mounting block  27 . Particularly, the fuse plate  22  (which is shown in isolation in  FIG.  2 C  for clarity) may include a rear portion  22   a  disposed on a rear surface  27   a  of the mounting block  27 , a front portion  22   b  disposed on a front surface  27   b  of the mounting block  27 , opposite the rear surface  27   a , and a fusible element  22   c  disposed on or adjacent a top surface  27   c  of the mounting block  27  and connecting the rear portion  22   a  to the front portion  22   b . The mounting block  27  may include a through hole  24  extending between and through the rear surface  27   a  and the front surface  27   b . The rear and front portions  22   a ,  22   b  of the fuse plate  22  may include respective first and second through holes  26   a ,  26   b  that are aligned with the through hole  24  of the mounting block  27 . The through holes  24 ,  26   a , and  26   b  are standard features of the commercially available ZCASE fuse sold by LITTELFUSE but are not relevant or necessary for the implementation of the fuse  18  within the fuse module  10  of the present disclosure. The through holes  24 ,  26   a , and  26   b  may therefore be omitted from the fuse  18  without departing from the scope of the present disclosure. The fuse  18  may further include an insulating cover  28  (shown in  FIG.  2 A  and omitted in  FIG.  2 B ) that fits over the fusible element  22   c  and attaches to the top surface  27   c  of the mounting block  27  (e.g., via snap fit, mechanical fasteners, etc.). 
     The fusible element  22   a  may be configured to melt, disintegrate, or otherwise open if current flowing through fuse plate  22  exceeds a predetermined threshold, or “current rating,” of the fuse  18 . In various examples, the fusible element  22   c  may include perforations, slots, thinned or narrowed segments, and/or various other features for making the fusible element  22   c  more susceptible to melting or opening than other portions of the fuse plate  22 . As shown in  FIG.  2 C , the fusible element  22   c  may have a generally X-shaped configuration. The present disclosure is not limited in this regard. 
     Referring to  FIGS.  3 A and  3 B , top views illustrating the busbar  14  and fuses  18  of the fuse module  10  in isolation are shown. The busbar  14  may include a plurality of rigid portions  14   a  and a plurality of flexible portions  14   b , wherein the flexible portions  14   b  extend between the rigid portions  14   a , and wherein the rigid portions  14   a  may be aligned with the fuses  18 . In various embodiments, the busbar  14  may be formed of a plurality of electrically conductive foils (e.g., copper foils) that are stacked together, wherein certain portions of the stacked foils are welded together (via molecular diffusion welding, for example) to define the rigid portions  14   a , and wherein the other portions of the stacked foils are not welded together to define the flexible portions  14   b . The flexible portions  14   b  may have a spring-like quality and may be biased toward a relaxed, planar state, wherein the rigid portions  14   a  are generally coplanar with the flexible portions  14   b  as shown in  FIG.  3 A . However, when a normal force is applied to the rigid portions  14   a  as indicated by the arrows in  FIG.  3 B  the flexible portions  14   b  may flex or bend, thereby allowing the rigid portions  14   a  to be moved into contact with the fuses  18  as further described below. When the normal force is removed, the flexible portions  14   b  may return to their relaxed, planar states shown in  FIG.  3 A . 
     Referring to  FIGS.  4 A and  4 B , detail views illustrating one of the pushrods  20  and a surrounding portion of the rear wall  15  of the housing  12  are shown (the pushrod  20  is omitted from  FIG.  4 B  and only an interior surface of the surrounding portion of the rear wall  15  is shown). It will be understood that all of the pushrods  20  and the corresponding, surrounding portions of the rear wall  15  shown in  FIGS.  1 A and  1 B  are substantially identical to the pushrod  20  and surrounding portion of the rear wall  15  shown in  FIGS.  4 A and  4 B , and that the illustrations of the pushrod  20  and surrounding portion of the rear wall  15  provided in  FIGS.  4 A and  4 B , and the corresponding description of the same provided below, shall apply to all of the pushrods  20  and surrounding portions of the rear wall  15  shown in  FIGS.  1 A and  1 B . 
     As shown in  FIG.  4 A , the pushrod  20  may have a cylindrical shaft portion  32  extending through an aperture  36  in the rear wall  15  of the housing  12 , and a cylindrical head portion  34  disposed within the housing  12 . The head portion  34  may have a diameter that is larger than a diameter of the shaft portion  32  and that is too large to fit through the aperture  36 . In various embodiments, the shaft portion  32  may extend through a tubular neck  33  that extends from a rear surface of the rear wall  15 , and an O-ring  35  (see  FIG.  5 A ) formed of a resilient material (e.g., rubber, plastic, etc.) may disposed radially intermediate an exterior surface of the shaft portion  32  and an interior surface of the neck  33  to form a seal therebetween. The present disclosure is not limited in this regard. 
     The head portion  34  may have a pair of diametrically opposed, rounded detents  38   a ,  38   b  extending from a rear surface thereof. Referring to  FIG.  4 B , the interior surface of the rear wall  15  may have a pair of diametrically opposed, curvilinear grooves  40   a ,  40   b  formed therein surrounding the aperture  36 . The curvilinear grooves  40   a ,  40   b  may extend along an imaginary circle having a diameter that is substantially equal to a distance between the rounded detents  38   a ,  38   b . The curvilinear grooves  40   a ,  40   b  may have floors  41   a ,  41   b  that are sloped such that each of the curvilinear grooves  40   a ,  40   b  gradually deepens in the clockwise direction from a shallow end  42   a ,  42   b  that is nearly coplanar with the interior surface of the rear wall  15  to a deep end  44   a ,  44   b  that is recessed from the interior surface of the rear wall  15  (e.g., having a depth equal to or greater than a height of the rounded detents  38   a , 38b). Dimples  46   a ,  46   b  may be formed in the shallow ends  42   a ,  42   b  of the curvilinear grooves  40   a ,  40   b , respectively. The dimples  46   a ,  46   b  made have a size and a shape adapted to accommodate tips of the detents  38   a ,  38   b  as further described below. 
     The pushrod  20  may be movable between a retracted position and an extended position relative to the interior surface of the rear wall  15 . In the retracted position, the detents  38   a ,  38   b  may be disposed within the deep ends  44   a ,  44   b  of the curvilinear grooves  40   a ,  40   b , respectively, and the head portion  34  of the pushrod  20  may be disposed in flat abutment with the interior surface of the rear wall  15 . To move the pushrod  20  from the retracted position to the extended position, the shaft portion  32  of the pushrod  20  may be rotated in the clockwise direction, causing the detents  38   a ,  38   b  to ride along the sloped floors  41   a ,  41   b  of the curvilinear grooves  40   a ,  40   b  and move from the deep ends  44   a ,  44   b  to the shallow ends  42   a ,  42   b , where the detents  38   a ,  38   b  may be received by the dimples  46   a ,  46   b , respectively. The pushrod  20  may thus be placed in the extended position (as shown in  FIG.  4 A ), wherein the head portion  34  of the pushrod  20  may be spaced apart from the interior surface of the rear wall  15 . The engagement between the detents  38   a ,  38   b  and the dimples  46   a ,  46   b  may hold or lock the pushrod  20  in the extended position by preventing the detents  38   a ,  38   b  from sliding back down the sloped floors  41   a ,  41   b  toward the deep ends  44   a ,  44   b  of the curvilinear grooves  40   a ,  40   b . To move the pushrod  20  back to the retracted position, the shaft portion  32  of the pushrod  20  may be rotated in the counterclockwise direction with sufficient force to unseat the detents  38   a ,  38   b  from the grooves  40   a ,  40   b  and rotate the detents  38   a ,  38   b  back to the deep ends  44   a ,  44   b  of the curvilinear grooves  40   a ,  40   b . In various embodiments, a rear end of the shaft portion  32  of the pushrod  20  may be adapted to receive or accommodate a tool to facilitate convenient, manual rotation of the pushrod  20 . For example, the rear end of the shaft portion  32  may have a slot  50  formed therein for accommodating a flathead screwdriver. The present disclosure is not limited in this regard. 
     Referring to  FIGS.  5 A- 5 D , a series of cross-sectional views illustrating the installation and removal of one of the above-described fuses  18  is provided. As shown in  FIG.  5 A , the fuse  18  may be inserted into the housing  12  between a rigid portion  14   a  of the busbar  14  and a fuse coupling portion  16   b  of one of the terminals  16 , with the rear portion  22   b  of the fuse plate  22  confronting, and parallel with, the rigid portion  14   a  of the busbar  14 , and with the front portion  22   b  of the fuse plate  22  confronting, and parallel with, the fuse coupling portion  16   b  of the terminal  16 . After the fuse  18  has been fully inserted into the housing  12 , the shaft portion  32  of the pushrod  20  may be rotated in the clockwise direction to move the pushrod  20  from the retracted position to the extended position as shown in  FIG.  5 B . When the pushrod  20  is extended, the pushrod  20  may push the rigid portion  14   a  of the busbar  14  into engagement with the rear portion  22   b  of the fuse plate  22  and may firmly clamp the fuse  18  between the rigid portion  14   a  and the fuse coupling portion  16   b  of the terminal  16 . An electrical pathway is thus established that extends through the busbar  14 , the rear portion  22   b  of the fuse plate  22 , the fusible element  22   c  of the fuse plate  22 , the front portion  22   b  of the fuse plate  22 , the fuse coupling portion  16   b  of the terminal  16 , and the conductor coupling portion  16   a  of the terminal  16 . As described above, the movement of the rigid portion  14   a  of the busbar  14  is facilitated by the flexure of the surrounding flexible portions  14   b  of the busbar  14  (see  FIG.  3 B ). 
     To remove the fuse  18  from the housing  12 , the shaft portion  32  of the pushrod  20  may be rotated in the counterclockwise direction to move the pushrod  20  from the extended position to the retracted position as shown in  FIG.  5 C . The fuse  18  is thereby unclamped and the electrical connection between the rigid portion  14   a  of the busbar  14  and the rear portion  22   b  of the fuse plate  22  is broken. The fuse  18  may thereafter be pulled or lifted out of the housing  12  without restriction as shown in  FIG.  5 D . 
     Referring to  FIG.  6   , an exemplary implementation of the fuse module  10  is shown. Ring terminals of electrical cables  52   a - e  may be fitted onto the threaded mounting posts  19  and may be secured the against the conductor coupling portions  16   a  of the terminals  16  with respective nuts  54  that may be tightened onto the mounting posts  19 . The electrical cable  52   c  may be coupled to a source of electrical power  56  (e.g., an automobile battery), and the other electrical cables  52   a , b, d, and e may be coupled to various electrical loads  58  (e.g., electrical systems within an automobile). Thus, when all of the pushrods  20  are moved to their extended positions, all of the electrical cables  52   a - e  may be placed in electrical communication with the busbar  14 . The fuse module  10  thereby provides fused electrical connections between the source of electrical power  56  and each of the loads  58 . Upon the occurrence of an overcurrent condition between the source of electrical power  56  and one or more of the loads  58 , the fusible element  22   c  in one or more of the fuses  18  may melt or otherwise separate, thereby arresting the flow of current therethrough to prevent or mitigate damage to connected electrical components. The blown fuses  20  may then be quickly and conveniently removed and replaced in the manner described above without requiring the removal or reinstallation of any removable fasteners (e.g., nuts, bolts, screws, etc.). 
     As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
     While the present disclosure makes reference to certain embodiments, numerous modifications, alterations and changes to the described embodiments are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claim(s). Accordingly, it is intended that the present disclosure not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.