Patent Publication Number: US-10325744-B2

Title: Hollow fuse body with notched ends

Description:
BACKGROUND 
     Field 
     The present invention relates generally to fuses. More specifically, the present invention relates to fuses that include a hollow fuse body. 
     Description of Related Art 
     Fuses are used as circuit protection devices and form electrical connections between sources of electrical power and components in circuits that are to be protected. A particular fuse design includes an electrically insulating, hollow fuse body, a fusible element disposed within the hollow fuse body, and electrically conductive endcaps coupled to ends of the hollow fuse body in electrical connection with respective ends of the fusible element. Typically, electrical connections are established between the endcaps and the ends of the fusible element by trapping or crimping the ends of the fusible element between exterior surfaces of the fuse body and interior surfaces of the end caps. A small amount of solder may be disposed within the endcaps prior to fitting the endcaps on the ends of the fuse body for securing the endcaps to the ends of the fuse body and improving the electrical connections with the fusible element. 
     Due to the tight tolerance between the hollow body and the endcaps and, very little solder flows around the fusible element. Generally, fuse endcaps fit onto the ends of a fuse body in a close clearance relationship therewith, with very little space between the exterior surfaces of the fuse body and the interior surfaces of the end caps. Thus, during assembly of the fuse, there may not be sufficient room between the endcaps and the fuse body to allow solder to reflow and achieve a consistent and reliable connection with the fusible element. It is with respect to these and other considerations that the present improvements may be useful. 
     SUMMARY 
     Hollow bodies and hollow body fuses are disclosed. Furthermore, methods to provide hollow bodies and hollow body fuses are disclosed. In one implementation, a hollow body includes a center portion and an end portion. An endcap may be coupled to the end portion. A cavity is formed between an inside surface of the endcap and an outer periphery of the end portion. A fusible element may be disposed within the hollow body, and may further be disposed within the cavity formed between the inside surface of the endcap and the outer periphery of the end portion, the fusible element extending along a substantially diagonal path through a center of the cavity. Solder may fill the cavity and surround the fusible element to create a resilient and durable solder connection to the fusible element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a fuse; 
         FIG. 2  illustrates an exemplary fuse endcap with solder disposed therein; 
         FIGS. 3-8  illustrate exemplary hollow body implementations. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a cross-sectional view of a fuse  300  in accordance with a non-limiting embodiment of the present disclosure. The fuse  300  may have a generally circular profile in cross-section, as viewed end-on from a bottom  302  or top  304  of the fuse  300 . Alternatively, the fuse  300  may have a generally rectangular profile in cross-section, as viewed end-on from the bottom  302  or the top  304  of the fuse  300 . The fuse  300  may be implemented as other shape profiles as well. The fuse  300  may have a hollow body  306 . The hollow body  306  may be ceramic, plastic, or other suitable electrically non-conducting material. A first endcap  308  may fit over a first end  310  of the hollow body  306  and a second endcap  312  may fit over a second end  314  of the hollow body  306 . 
     Solder  316  may be disposed within each of the endcaps  308  and  312 . Furthermore, as will be described in further detail below, the solder  316  may be disposed along a periphery of the hollow body  306 . The fuse  300  further includes a fusible element  318 , such as wire. The fusible element  318  may be disposed within the hollow body  306 . Furthermore, the fusible element  318  may extend along a bottom portion  320  of the first end  310 . The fusible element  318  may also extend along a top portion  322  of the second end  314 . 
     The hollow body  306  includes a central portion  324 . The central portion  324  has an outer cross-sectional profile of a first size. The hollow body  306  also includes a first end portion  326  that terminates at the first end  310 . The first end portion  326  has an outer cross-sectional profile of a second size, where the second size is less than the first size. Therefore, the first end portion  326  is narrower than the central portion  324 . In other words, depending on a shape of the hollow body  306 , an area, perimeter, diameter, circumference, or the like associated with the first size is greater than an area, perimeter, diameter, circumference, or the like associated with the second size. The hollow body  306  also includes a second end portion  328  that terminates at the second end  314 . The second end portion  328  has an outer cross-sectional profile of a second size, where the second size is less than the first size. Therefore, the second end portion  328  is narrower than the central portion  324 . In other words, an area, perimeter, diameter, circumference, or the like associated with the first size is greater than the area, perimeter, diameter or circumference associated with the second size. 
     The central portion  324  of the hollow body  306  integrally couples to the first end portion  326  at a shoulder  330  that extends inwardly to join to the first end portion  326 . Similarly, the central portion  324  of the hollow body  306  integrally couples to the second end portion  328  at a shoulder  331  that extends inwardly to join to the second end portion  328 . 
     The fusible element  318  extends through a cavity  332  that is defined between an outer periphery of the first end portion  326  and an inside surface of the first endcap  308 . The fusible element  318  extends along a substantially diagonal path through a center of the cavity  332  and terminates at an end  335  that is sandwiched between an inside surface of the first endcap  208  and an outer periphery of the central portion  324 . The cavity  332  enables the solder  316  to completely surround at least a portion of the fusible element  318  disposed within the cavity  332 . 
     Similarly, the fusible element  318  is disposed within a cavity  337  that is defined between an outer periphery of the second end portion  328  and an inside surface of the second endcap  312 . The fusible element  318  extends along a substantially diagonal path through a center of the cavity  337  and terminates at an end  339  that is sandwiched between an inside surface of the second endcap  312  and an outer periphery of the central portion  324 . The cavity  337  enables the solder  316  to completely surround at least a portion of the fusible element  318  disposed within the cavity  337 . 
     In one embodiment, the fusible element  318  does not come into direct contact with an outer periphery of the first end portion  326 . That is, the fusible element  318  is offset from the outer periphery of the first and portion  326 . Furthermore, in one embodiment, the fusible element  318  does not come into direct contact with an outer periphery of the second end portion  328 . That is, the fusible element  318  is offset from an outer periphery of the second and portion  328 . Rather, the solder  316  is disposed between the fusible element  318  and an outer periphery of the first end portion  326 , and the  316  is disposed between the fusible element  318  and an outer periphery of the second end portion  328 . 
       FIG. 2  illustrates and exemplary endcap  400  with solder  402  disposed therein. The endcap  400  may be substantially similar to the first and second endcaps  308  and  312  described above. In a process or method of manufacturing the fuse  300 , the endcap  400  may be at least partially fitted over the first end  310  of the hollow body  306 . Furthermore, another endcap  400  may be at least partially fitted over the second end  314  of the hollow body  306 . The fusible element  318  may be arranged within the interior and further arranged on the exterior of the hollow body  306 , as illustrated in  FIG. 1 , prior to the fitting of one or more of the endcaps  400 . The process of fitting the endcaps  400  over the hollow body  306  may include heating the endcaps  400  to melt the solder  402 . The process of melting the solder enables the solder to flow at least into the cavities  332 . 
       FIG. 3  illustrates an exemplary embodiment of a hollow body  500 . The hollow body  500  may be implemented as part of a fuse, such as the fuse  300  described above. The hollow body  500  has an outer square cross-sectional profile. The hollow body  500  may include a central portion  502 . The central portion  502  has an outer square cross-sectional profile. The central portion  502  has an outer cross-sectional profile of a first size. The hollow body  500  also includes a first end portion  504 . The first end portion  504  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, an area or perimeter associated with the first size is greater than an area or perimeter associated with the second size. The hollow body  500  also includes a second end portion  506 . The second end portion  506  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, an area or perimeter associated with the first size is greater than an area or perimeter associated with the second size. 
       FIG. 4  illustrates an exemplary embodiment of a hollow body  600 . The hollow body  600  may be implemented as part of a fuse, such as the fuse  300  described above. The hollow body  600  has an outer circular cross-sectional profile. The hollow body  600  may include a central portion  602 . The central portion  602  has an outer circular cross-sectional profile. The central portion  602  has an outer cross-sectional profile of a first size. The hollow body  600  also includes a first end portion  604 . The first end portion  604  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, a circumference or diameter associated with the first size is greater than a circumference or diameter associated with the second size. The hollow body  600  also includes a second end portion  606 . The second end portion  606  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, a circumference or diameter associated with the first size is greater than a circumference or diameter associated with the second size. 
       FIG. 5  illustrates an exemplary embodiment of a hollow body  700 . The hollow body  700  may be implemented as part of a fuse, such as the fuse  300  described above. The hollow body  700  has an outer square cross-sectional profile. The hollow body  700  may include a central portion  702 . The central portion  702  has an outer square cross-sectional profile. The central portion  702  has an outer cross-sectional profile of a first size. The hollow body  700  also includes a first end portion  704 . The first end portion  704  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, an area or perimeter associated with the first size is greater than an area or perimeter associated with the second size. The hollow body  700  also includes a second end portion  706 . The second end portion  706  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, an area or perimeter associated with the first size is greater than an area or perimeter associated with the second size. 
     The hollow body  700  illustrated in  FIG. 5  may include one or more notches  708 . The one or more notches  708  may be entirely or partially filled with solder when an endcap (e.g., endcap  400 ) is pressed onto an end portion (e.g., first end portion  704 ) of the hollow body  700 . Heat may be applied to the endcap to enable the solder to flow. Thus, the one or more notches  708  may aid in the retention of an endcap pressed onto an end portion of the hollow body  700 . More particularly, hardened solder in the one or more notches  708  may couple or be integral with hardened solder within the cavity  332 . Therefore, the hardened solder in the one more notches  708  serves as an anchor for the endcap pressed onto an end portion of the hollow body  700 . 
       FIG. 6  illustrates an exemplary embodiment of a hollow body  800 . The hollow body  800  may be implemented as part of a fuse, such as the fuse  300  described above. The hollow body  800  has an outer circular cross-sectional profile. The hollow body  800  may include a central portion  802 . The central portion  802  has an outer circular cross-sectional profile. The central portion  802  has an outer cross-sectional profile of a first size. The hollow body  800  also includes a first end portion  804 . The first end portion  804  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, a circumference or diameter associated with the first size is greater than a circumference or diameter associated with the second size. The hollow body  800  also includes a second end portion  806 . The second end portion  806  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, a circumference or diameter associated with the first size is greater than a circumference or diameter associated with the second size. 
     The hollow body  800  illustrated in  FIG. 6  may include one or more anchor ledges  808 . The one or more anchor ledges  808  may be entirely or partially surrounded with solder when an endcap (e.g., endcap  400 ) is pressed onto an end portion (e.g., first end portion  804 ) of the hollow body  800 . Heat may be applied to the endcap to enable the solder to flow around the one or more anchor ledges  808  and rigidly encapsulate the one or more anchor ledges  808  when the solder hardens. Thus, the one or more anchor ledges  808  may aid in the retention of an endcap pressed onto an end portion of the hollow body  800 . 
       FIG. 7  illustrates an exemplary embodiment of a hollow body  900  in cross-section. The hollow body  900  may be implemented as part of a fuse, such as the fuse  300  described above. The hollow body  900  may include a central portion  902 . The central portion  902  has an outer cross-sectional profile. The central portion  902  has an outer cross-sectional profile of a first size. The hollow body  900  also includes a first end portion  904 . The first end portion  904  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, an area, circumference or diameter associated with the first size is greater than an area, circumference or diameter associated with the second size. The hollow body  900  also includes a second end portion  906 . The second end portion  906  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, an area, circumference or diameter associated with the first size is greater than an area, circumference or diameter associated with the second size. 
     The hollow body  900  may include a layer of metallization  908  on each of the first end portion  904  and second end portion  906 . Solder (not shown) may come in contact with the layer of metallization  908  when an endcap (e.g., endcap  400 ) is pressed onto an end portion (e.g., first end portion  904 ) of the hollow body  900 . Thus, since the layer of metallization  908  is in contact with the solder and with portions of the fusible element  910  (as shown in  FIG. 7 ), the layer of metallization  908  may facilitate robust electrical conductivity between the solder, the fusible element  910 , and an endcap (e.g., endcap  400 ) that is pressed onto an end portion (e.g., first end portion  904 ) of the hollow body  900 . 
       FIG. 8  illustrates an exemplary embodiment of a hollow body  1000 . The hollow body  1000  may be implemented as part of a fuse, such as the fuse  300 . The hollow body  1000  has an outer circular cross-sectional profile. The hollow body  1000  may include a central portion  1002 . The central portion  1002  has an outer circular cross-sectional profile. The central portion  1002  has an outer cross-sectional profile of a first size. The hollow body  1000  also includes a first end portion  1004 . The first end portion  1004  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, a circumference or diameter associated with the first size is greater than an area or diameter associated with the second size. The hollow body  1000  also includes a second end portion  1006 . The second end portion  1006  has an outer cross-sectional profile of a second size, where the second size is less than the first size. In other words, a circumference or diameter associated with the first size is greater than an area or diameter associated with the second size. 
     Each of the first end portion  1004  and second end portion  1006  may have a generally concave or curved shape  1008 . In one implementation, the generally concave or curved shape  1008  of each of the first and portion  1004  and the second and portion  1006  allows for the elimination of the shoulders  330  described above with regard to the fuse  300  (see  FIG. 1 ). An exemplary fusible element  1010  is illustrated in  FIG. 8  to show that a cavity  1012  is at least formed between each of the portions  1004  and  1006  and the fusible element  1010 . Therefore, solder may and occupy the cavities  1012  and completely surround adjacent portions of the fusible element  1010  upon coupling endcaps to the hollow body  1000 . 
     While hollow body fuses and a method for manufacturing structurally hollow body fuses have been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the claims of the application. Other modifications may be made to adapt a particular situation or material to the teachings disclosed above without departing from the scope of the claims. Therefore, the claims should not be construed as being limited to any one of the particular embodiments disclosed, but to any embodiments that fall within the scope of the claims.