Patent Publication Number: US-10325747-B2

Title: In-line high current fuse holder assembly

Description:
FIELD OF THE DISCLOSURE 
     The disclosure relates generally to electrical protection devices, and more particularly, to an apparatus for securing electrical protection devices. 
     BACKGROUND OF THE DISCLOSURE 
     Electrical protection devices such as fuses have long been used in electrical devices for providing an interruptible electrical connection between a source of electrical power and a component in an electrical circuit that is to be protected. For example, upon the occurrence of an overcurrent condition in a circuit, such as may result from a short circuit or other sudden electrical surge, an element within the fuse may separate and interrupt the flow of electrical current to a protected circuit component, thereby preventing or mitigating damage to the component that would otherwise result if the overcurrent condition were allowed to persist. 
     A variety of different types of fuse holders are known to provide electrical interfaces for overcurrent protection fuses. One type of fuse holder is an inline fuse holder that electrically connects a ferrule fuse within an electrical system. Among several applications, the inline fuse holder may be used in solar photovoltaic systems. The inline fuse holder assembly typically comprises a holder body having two pieces that releasably attach to one another using a compression nut and define an interior space for receiving the fuse. 
     Typically, at least two contacts of the inline fuse electrically connect to the terminals of the fuse when the fuse is received in the fuse holder body. The contacts include wire connectors that extend outside the holder body. The wire connectors are connectable to (e.g., crimped onto) wires that are electrically connected to the electrical system. 
     SUMMARY 
     In view of the foregoing, what is needed is an inline high current fuse holder assembly for securing an electrical protection device (e.g., a fuse) therein. In one approach, an apparatus includes a conductor and a terminal coupling the conductor to the electrical protection device. The terminal may include an end cap having a cavity for receiving and securing the conductor, a set of contact elements extending from a base member, wherein the base member is coupled to the end cap, and wherein a body of the electrical protection device coupled to the base member. 
     In another approach, a fuse assembly includes a conductor and a plurality of terminals coupling the conductor to a fuse. Each of the plurality of terminals may include an end cap having a cavity for receiving and securing the conductor, and a set of contact elements extending from a base member, wherein the base member is coupled to the end cap. The fuse assembly may further include a cover adjacent the plurality of terminals, wherein the cover engages the set of contact elements in a closed position. 
     In yet another approach, a method of securing a fuse element includes providing a terminal coupling a conductor to a fuse, the terminal including an end cap having a cavity for receiving and securing the conductor, and a set of contact elements extending from a base member. The base member may be coupled to the end cap, and the base member may be coupled to a fuse body of the fuse. The method may further include providing a cover adjacent the terminal, wherein the cover engages the set of contact elements in a closed configuration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate exemplary approaches of the disclosed embodiments so far devised for the practical application of the principles thereof, and in which: 
         FIG. 1  is an isometric view of a fuse assembly according to an exemplary approach of the disclosure; 
         FIG. 2  is side view of the fuse assembly of  FIG. 1  according to an exemplary approach of the disclosure; 
         FIG. 3  is a side view of the fuse assembly of  FIG. 1  according to an exemplary approach of the disclosure; 
         FIG. 4  is an isometric view of a terminal of the fuse assembly of  FIG. 1  according to an exemplary approach of the disclosure; 
         FIG. 5  is a side view of the terminal of  FIG. 4  according to an exemplary approach of the disclosure; 
         FIG. 6  is side view of a fuse assembly according to an exemplary approach of the disclosure; 
         FIG. 7  is a perspective view of a fuse assembly with a cover according to an exemplary approach of the disclosure. 
         FIG. 8  is an end cross-sectional view of the fuse assembly and cover of 
         FIG. 7  according to an exemplary approach of the disclosure. 
         FIG. 9  is a perspective view of a first portion of the cover of  FIG. 7  according to an exemplary approach of the disclosure. 
         FIG. 10  is a perspective view of a second portion of the cover of  FIG. 7  according to an exemplary approach of the disclosure. 
         FIG. 11  is an end cross-sectional view of the fuse assembly and cover of 
         FIG. 7  according to an exemplary approach of the disclosure. 
         FIG. 12  is a flow chart illustrating an exemplary method according to an exemplary approach of the disclosure. 
     
    
    
     The drawings are not necessarily to scale. The drawings are merely representations, not intended to portray specific parameters of the disclosure. The drawings are intended to depict typical embodiments of the disclosure, and therefore should not be considered as limiting in scope. In the drawings, like numbering represents like elements. 
     Furthermore, certain elements in some of the figures may be omitted, or illustrated not-to-scale, for illustrative clarity. Furthermore, for clarity, some reference numbers may be omitted in certain drawings. 
     DETAILED DESCRIPTION 
     Embodiments in accordance with the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings. The system/circuit 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 be thorough and complete, and will fully convey the scope of the system and method to those skilled in the art. 
     For the sake of convenience and clarity, terms such as “top,” “bottom,” “upper,” “lower,” “vertical,” “horizontal,” “lateral,” and “longitudinal” will be used herein to describe the relative placement and orientation of various components and their constituent parts. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
     As used herein, an element or operation recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or operations, 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. 
     As stated above, described herein are approaches for securing an electrical protection device, such as midi and mega fuses, or a transient-voltage-suppression (TVS) diode. In one approach, an apparatus includes a conductor and a terminal coupling the conductor to the electrical protection device, wherein the terminal includes: an end cap having a cavity for receiving and securing the conductor; a set of (i.e., one or more) contact elements extending from a base member, the base member coupled to the end cap; and a body coupled to the base member, the body containing the electrical protection device. In some approaches, the electrical protection device is a fuse element having a fuse blade and fuse body, wherein the fuse blade is disposed between the set of contact elements. In some approaches, the apparatus further includes a cover adjacent the terminal, wherein the cover is configured to engage the contact elements to increase a contact force and electrical connection between the set of contact elements and the fuse blade. 
       FIGS. 1-3  illustrate an exemplary embodiment of an inline fuse assembly  100  in accordance with the present disclosure. As shown, the fuse assembly  100  may include one or more terminals  101 A-B coupled to an electrical protection device  102  (e.g., a fuse) having a fuse blade  104  and a fuse body  106 . The fuse assembly  100  may further include a conductor  108 , such as one or more wires, and a pair of electrically conductive end caps  110 A-B that electrically couple the conductor  108  to the fuse  102 . The conductor  108  may provide an electrical connection between the fuse  102  and various other circuit elements (not shown) for which the fuse  102  may provide protection against certain overcurrent conditions. 
     As shown, the terminals  101 A-B are disposed on opposite sides of the fuse  102 , and couple the conductor  108  to the fuse  102 . As further shown, the terminals  101 A-B include respective end caps  110 A-B, a set of contact elements  112 A-D coupled to and disposed on opposite sides of the fuse blade  104 , and a set of base members  116 A-B supporting the set of contact elements  112 A-D and the fuse body  106 . 
     The fuse blade  104  extends through the fuse body  106 , which may be formed of any suitable, electrically insulating material, including, but not limited to, glass, ceramic, plastic, and the like. The end caps  110 A-B may be formed of any suitable, electrically conductive material, including, but not limited to, copper, aluminum, brass, gold, silver, or other metallic conductors. The fuse blade  104  may be formed of any suitable electrically conductive material, including, but not limited to, copper, tin, nickel, and the like, and may be formed as a ribbon, wire, metal link, spiral wound wire, film, electrically conductive core deposited on a substrate, or any other suitable structure that is configured to separate or otherwise break the electrical connection between the end caps  110 A-B upon the occurrence of an overcurrent condition. As will be appreciated, the particular size, volume, configuration, and conductive material of the fuse blade  104  may all contribute to the rating of the fuse  102 . 
     As demonstrated in  FIG. 1 , the stripped end of the conductor  108  may be longitudinally inserted into a cavity  120  formed in the end cap  110 A. Although not shown, a similar conductor may be inserted into a cavity formed in opposite end cap  110 B. Once the conductor  108  has been inserted thusly, the end cap  110 A, which may be formed of a malleable material, may be crimped, crushed, bent, flattened, or otherwise deformed (hereinafter collectively referred to as “crimped”) so as to pinch and securely trap the end of the conductor  108  therein. Depending on its rigidity, the end cap  110 A may be crimped using a manual tool (e.g. pliers), by hand (e.g. manually pinched between fingers), or by various automated means. The conductor  108  may thereby be held in firm engagement with the terminal  101 A, and a secure electrical connection may be established therebetween without requiring additional fasters, adhesives, or the application of solder. 
     Referring now to  FIGS. 4-5 , one terminal of the fuse assembly  100  will be described in greater detail. As shown, the terminal  101 A includes the end cap  110 A integrally coupled to the base member  116 A, and first and second contact members  112 A-B extending from the base member  116 A. In some embodiments, the base member  116 A includes a reinforcement member  124  extending between the end cap  110 A and the first and second contact members  112 A-B. The base member  116 A further includes a first section  126  extending between the first and second contact members  112 A-B, and a second section  128  configured as a tab with an opening  130  formed therein. The second section  128  receives the fuse body  106  along a top surface  132  thereof, and the opening  130  may receive one or more mechanical fastening elements (not shown) of the fuse body  106  to secure the fuse body  106  adjacent to the first and second contact elements  112 A-B. 
     As further shown, the first and second contact elements  112 A-B respectively include first bowed sections  136 A-B, straight sections  137 A-B coupled to the first bowed sections  136 A-B, second bowed sections  138 A-B, and free ends  140 A-B. In some embodiments, the free ends  140 A-B are angled away from one another and define an opening  144  therebetween configured to receive the fuse blade  104 . The first and second contact elements  112 A-B extend from the first section  126 , and may be integrally formed with the base member  116 A. 
     Turning now to  FIG. 6 , another exemplary embodiment of an inline fuse assembly  200  in accordance with the present disclosure will be described in greater detail. The fuse assembly  200  may share similar features to that of the fuse assembly  100  depicted in  FIGS. 1-5 . As shown, the fuse assembly  200  may include one or more terminals  201 A-B coupled to an electrical protection device  202  (e.g., a fuse). The fuse assembly  200  may further include a conductor  208 , such as one or more wires, and a pair of electrically conductive end caps  210 A-B that electrically couple the conductor  208  to the fuse  202 . The conductor  208  may provide an electrical connection between the fuse  202  and various other circuit elements (not shown) for which the fuse  202  may provide protection against certain overcurrent conditions. 
     The terminals  201 A-B are disposed on opposite sides of the fuse  202 , and couple the conductor  208  to the fuse  202 . As shown, the terminals  201 A-B include respective end caps  210 A-B, a set of contact elements  212 A-B coupled to and disposed on opposite sides of the fuse blade  204 , and a set of base members  216 A-B supporting the set of contact elements  212 A-D and the fuse body  206 . 
     The conductor  208  may include an insulating jacket  209  and grommets  211  in some embodiments. Alternatively, it is contemplated that the insulating jacket  209  may be omitted and that the conductor  208  may include only one or more bare conductor(s). The conductor  208  may be formed of any suitable, electrically conductive material, including, but not limited to, copper, aluminum, brass, gold, silver, or other metallic conductors. The insulating jacket(s)  209  may be formed of any suitable, insulating material, including, but not limited to, polyethylene, polyvinyl chloride (PVC), polypropylene, TEFLON, and the like. 
     In this embodiment, the set of contact elements  212 A-B each include a plurality of finger-like contact strips  215  extending upwards from the base members  216 A-B, the contact strips  215  being provided to increase the number of contact points between the terminals  201 A-B and the fuse blade  204 . During assembly, the fuse blade  204  of the fuse  202  may be inserted between complementary and opposing fingers  215  of each contact element  212 A-B. 
     Turning now to  FIGS. 7-8 , an over-molding or cover  350  for use with a fuse assembly  300  according to exemplary embodiments will be described in greater detail. As shown, the cover  350  may be disposed over a protection device, such as fuse  102  and terminals  101 A-B shown in  FIG. 1 . The assembly  300  may further include a conductor (not shown) and one or more electrically conductive end caps  310  that electrically couple the conductor to the fuse. As shown, the cover  350  may include a first section  380  matingly engaged with a second section  381 , for example, by a set of overlapping tabs  382  and  383 . In some embodiments, the first and second sections  380 ,  381  are substantially equal halves of a hollow cylinder configured to house the protection device therein. The cover  350  may be injection molded, and may be made from plastic, rubber, or other durable, wear-resistant materials. 
     In some embodiments, one or more releasable fasteners  370  (e.g., a latch, clasp, hook tab and openings, etc.) may be used to further secure the first and second sections  380 ,  381  of the cover  350  in place. In the embodiment shown, each fastener  370  is a latch pivotably coupled at a first end to a pin  390 , which is secured between walls of a fastener housing  384  extending from an exterior surface  385  of the second section  381 . Each fastener  370  further includes a hook tab  386  disposed at a second end thereof for engagement within a recess  387  formed in an exterior surface  388  of the first section  380  of the cover  350 . As shown, each recess  387  may further define a recess hook tab  389  matingly engaged with the hook tab  386  of the fastener  370 . Each fastener  370  may be flexible or rigid, and once engaged about the first and second sections  380 ,  381 , effectively “locks” the fuse assembly  300  into a closed configuration/position. 
     Turning now to  FIGS. 9-11 , interior portions of the cover  350  according to exemplary embodiments will be described in greater detail. As shown in  FIG. 9 , the first section  380  includes a first set of protrusions  352  and a second set of protrusions  353 , each including a channel  354  provided therebetween. In exemplary embodiments, each of the first and second sets of protrusions  352 ,  353  extends from an interior surface  355  of the first section  380  towards the second section  381 . 
     As more clearly demonstrated in  FIG. 10 , the second section  381  includes a plurality of support ribs  360 A-D extending from an interior surface  361  thereof. Each of the plurality of support ribs  360 A-D may include a central recess  363  to receive the protection device, such as the fuse  102  and terminals  101 A-B shown in  FIG. 1 . In some embodiments, the fastener housing  384  extends from the interior surface  361  towards the first section  380 . As shown, the fastener housing  384  is provided adjacent support rib  360 A and support rib  360 D to provide a platform for each electrically conductive end cap  310 . 
     During use, the cover  350  may be brought from an open position to a closed position, for example as shown in  FIG. 11 , by securing the first section  380  atop the second section  381 . Once in place, an inner sloped surface  365  of the second set of protrusions  353  engage respective free ends  340 A-B of the first and second contact elements  312 A-B. More specifically, as the free ends  340 A-B move further into the channel  354  between the second set of protrusions  353 , the inner sloped surfaces  365  cause the first and second contact elements  312 A-B to be brought closer together. In exemplary embodiments, inner corners  366 A-B and straight sections  337 A-B make contact with the fuse blade  304 , as shown. Thus, the cover  350  is configured to increase a contact force and electrical connection between the first and second contact elements  312 A-B and the fuse blade  304 . When both the first and second contact elements  312 A-B are engaged and coupled to the fuse blade  304 , current can flow through the first and second contact elements  312 A-B via the fuse  302 . 
     As further shown, the support rib  360 D is configured to receive the first and second contact elements  312 A-B within the central recess  363 . For example, a recess base  392  may support the first section  326  extending between the first and second contact members  312 A-B. An inner sidewall  393  of the central recess  363  surrounds and/or is in abutment with the first bowed sections  336 A-B of the first and second contact members  312 A-B, respectively. As a result, the support rib  360 D may provide a mechanical/physical support or seating area, which increases the contact force and overall stability of the first and second contact elements  312 A-B and the fuse blade  304 . 
     Turning now to  FIG. 12 , a method for securing an electrical protection device within an assembly will be described in greater detail. The method  400  includes providing a terminal coupling a conductor to a fuse, as shown at block  401 . In some embodiments, the terminal includes an end cap having a cavity for receiving and securing the conductor, and a set of contact elements extending from a base member, wherein the base member coupled to the end cap. The terminal may further include a fuse body of the electrical protection device coupled to the base member, a fuse blade extending from opposite sides of the fuse body. 
     The method  400  further includes coupling the fuse to the base member, as shown at block  403 , wherein a fuse blade of the fuse extends between and engages the set of contact elements, as shown at block  405 . In some embodiments, the base includes an opening for engaging the fuse body. In some embodiments, the set of contact elements is bi-furcated or trifurcated to enable as much contact area as possible. In some embodiments, the set of contact elements may include a first contact element and a second contact element, each of the first and second contact elements having at least one bowed section, a straight section coupled to the at least one bowed section, and a free end for engaging a sloped surface of the cover. 
     The method  400  further includes causing a cover adjacent the terminal to engage the plurality of contact elements as the cover moves from an open position to a closed position, as shown at block  407 . In some embodiments, the set of contact elements may be biased together as in interior component of the cover engages a free end of each of the set of contact elements. In one embodiment, the cover may be opened to insert/remove the fuse. In one embodiment, the cover may include a first section matingly engaged with a second section, for example, by a set of overlapping tabs. In one embodiments, the first and second sections are substantially equal halves of a hollow cylinder configured to house the protection device therein. In one embodiment, the cover may be brought from an open position to a closed position, which causes an inner sloped surfaces of the cover to engage respective free ends of the first and second contact elements. As the free ends move further into a channel of the cover, the inner sloped surfaces cause the first and second contact elements to be brought closer together. In some embodiments, a plurality of support ribs are formed within a lower half of the cover, wherein the plurality of support ribs are configured to receive the first and second contact elements therein to provide a seating area for the first and second contact elements. 
     The method  400  may further include securing the set of contact elements together using a fastener around the cover. In some embodiments, the fastener is a releasable fastener (e.g., a latch, clasp, hook tab and openings, etc.) used to effectively “lock” the terminal into a closed position around the fuse. In some embodiments, each fastener is a latch element pivotably coupled at a first end to a pin, which is secured between walls of a fastener housing extending from an exterior surface of the second section. Each fastener may further include a hook tab disposed at a second end thereof for engagement within a recess formed in an exterior surface of the first section of the cover. In some embodiments, each recess may further define a recess hook tab that is matingly engaged with the hook tab of the fastener. 
     While the present disclosure has been described with reference to certain approaches, numerous modifications, alterations and changes to the described approaches are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claims. Accordingly, it is intended that the present disclosure not be limited to the described approaches, but that it has the full scope defined by the language of the following claims, and equivalents thereof. While the disclosure has been described with reference to certain approaches, numerous modifications, alterations and changes to the described approaches are possible without departing from the spirit and scope of the disclosure, as defined in the appended claims. Accordingly, it is intended that the present disclosure not be limited to the described approaches, but that it has the full scope defined by the language of the following claims, and equivalents thereof.