Abstract:
A circuit breaker adapter is disclosed for use in a fuse holder therein replacing a blade type fuse. The adapter includes a housing and a modified circuit breaker where pronged terminals are pivotally attached conductive articulable extensions. The housing is a contiguous block of material that receives the modified circuit breaker and gripping clips of the fuse holder. The housing has a center chute shaped section that holds the circuit breaker. In particular, the inside of the housing has a pair of accessible open cavities to receive the extensions similar to many fuses. The circuit breaker literally plugs into sockets on the housing, and the extensions are rotated outward into one of the accessible open cavities. The adapter may be placed into the fuse holder.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured and used by or for the Government of the United States of America for Governmental purposes without the payment of any royalties thereon or therefore. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to protective electrical circuit devices and more particularly to a circuit breaker adapter that enables a circuit breaker to be utilized in a fuse holder. 
     2. Background 
     The United States Navy and Coast Guard have a number of combat ships fitted with highly automated guns that utilize an electrically powered gun mount to control the gun. The Mark gun (MK-75) is a three-inch gun with a range of ten  10  nautical miles and can fire up to eighty rounds per minute. The high level performance guns are lightweight and have low manning requirements. The Mk-75 is well suited for installation on smaller combat vessels, frigates and cutters. 
     The first United States produced gun mount for the MK-75 was delivered in August 1978. Currently, MK-75 guns are on some guided missile frigates and some Navy hydrofoils. The Coast Guard&#39;s cutters are equipped with automated guns MK-75 guns, where the gun mount is remotely controlled. The gun mounts control the train and elevation of the gun, and the protective electrical devices that are a part of the electrically powered gun mount systems are starting to exhibit signs of aging, as evidenced by a higher incidence of blown fuses. This spike in demand has depleted the entire government stock of these legacy parts, which are SCR fuses. Furthermore, the cost and the time to replace are unacceptably too long and high in cost. The United States Navy and Coast Guard need a timely and cost effective solution to keep the electrically powered gun mounts operational. 
     SUMMARY OF THE INVENTION 
     The disclosed invention is an adapter that enables a circuit breaker to be installed in place of a fuse in a fuse holder on a vessel and in any other suitable application. Installation of a new fuse is commonly referred to “plug and play”, where a blown fuse is pulled-out of a pair of electrically conductive gripping clips in a fuse holder and the new fuse is pushed-in the pair of clips, therein reestablishing a closed, working, protected electrical circuit. One advantage of a circuit breaker is that with an overage current, the circuit breaker trips protecting the circuit but unlike a blown fuse, which must be replaced, the tripped circuit breaker only needs to be reset. Some circuit breakers are self-resetting. 
     Another advantage of the invented adapter is that the existing fuse panels may be used, obviating the cost and time needed to install a circuit breaker panel. The option to rewire gun control panels to accommodate circuit breakers is obviated. Installing a circuit breaker panel requires a lot of time, effort, and money. 
     An aspect of the invention is that the adapter is suitable for a single fuse holders and fuse holders that may hold a plurality of fuses. The adapter permits the simultaneous use of both circuit breakers and fuses. A fuse holder has an electrically insulating plate with one or more insular elongate bays, wherein each bay has a pair of clamping fuse clips. A common variation of a fuse clip has a pair of opposing electrically conductive contacts for clamping a knife-blade-end of a fuse. A fuse with a blade element, for example, an SCR fuse, includes a center section that is an elongate cylindrical element and a pair of outboard elongate sections that are similar in shape to a blade. The blade element has an overall length that extends lengthwise through the cylindrical element. The blade element has a center fusible portion that is enclosed within the cylindrical element. The elongate sections have a blade thickness, and the elongate sections project from opposing ends of the center elongate cylindrical element. 
     The fuse is positioned in the fuse holder by forcing the blade element into the clips, causing each clip to springedly widen as it receives the elongate section of the blade element. A gripping force is generated by the clips on the blade element, securing the fuse in the bay of the fuse holder. 
     The invented adapter enables the use of a minimally modified circuit breaker in a legacy fuse holder. The circuit breaker has a first pronged terminal and a second pronged terminal spaced by a separation length. A first arcuate conductive articulable extension is pivotally attached to the first pronged terminal. A second arcuate conductive articulable extension is pivotally attached to the second pronged terminal. The articulable extensions may be pivoted outwardly from an assembly position where they are closely aligned with the pronged terminals to a use position. The articulable extensions are nearly orthogonal to the pronged terminals, and aligned to be nearly longitudinal. The arcuate conductive articulable extensions have an individual thickness that is comparable to the thickness of the elongate sections of the blade element and an individual length that cumulatively spans a distance comparable to the overall length of the fuse minus the separation length of the pronged terminals. Depending on the selection of the circuit breaker, the individual length of the articulable extensions is usually about the length of the elongate sections of the blade element. The articulable extensions are arcuate to permit pivoting from the assembly position to the use position. 
     The adaptor further includes an electrical insulating chute shaped housing, where the housing is a contiguous block of material that receives the modified circuit breaker with the articulable extensions and the gripping clips. The housing has a first accessible open cavity and a second accessible open cavity, where each accessible open cavity is open on a bottom side (the bottom side of the housing covers the clips mounted on the fuse holder&#39;s electrically insulating plate). Each accessible open cavity is sufficiently large to accommodate a clip gripping an articulable extension. The top side of the housing is chute shaped, and it has two slotted sockets, where their center points are spaced by the separation length. Each socket extends to one of the accessible open cavities. The sockets provide passages large enough to accommodate the articulable extensions and terminals in the assembly position. 
     The circuit breaker adapter is assembled by plugging the articulable extensions into sockets in the chute shaped portion of the housing. The modified circuit breaker is seated in the chute section of the housing and the articulable extensions are protruding from the bottom side of the housing. Assembly is completed by pivoting the articulable extensions outboard to the use position, into the accessible open cavities of the housing. The chute shaped housing is locked onto the circuit breaker, and the extensions are positioned to engage the clips on a fuse holder. The housing has an overall length that may span the entire length of the bay of the fuse holder, but this extra length is generally not required. 
     Another advantage of the invented circuit breaker adapter is that a tripped reset button may be reset without removing the circuit breaker adapter or cutting off the power. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing invention will become readily apparent by referring to the following detailed description and the appended drawings in which: 
         FIG. 1  is an elevated plan view of a conventional legacy fuse holder that can hold up to three fuses, where currently there are two fuses, each fuse in a bay having a pair of clamping fuse clips, where each clip grips an end of a blade section therein securing the fuse; 
         FIG. 2  is an elevated view of a conventional n SCR fuse with a conductive blade that functions in part as a structural element for the SCR fuse; 
         FIG. 3  is an elevated perspective view of a circuit breaker fitted with a circuit breaker adapter that enables a modified circuit breaker to be utilized in a fuse holder; 
         FIG. 4  is an elevated plan view of a three bay fuse holder, as shown in  FIG. 1 , that is currently holding two circuit breakers, each of which are fitted with a circuit breaker adapter enabling the circuit breakers to be utilized instead of or in combination with fuses having a blade; 
         FIG. 5  is a frontal view of a circuit breaker adapter; 
         FIG. 6 a    is a frontal view of a modified circuit breaker having extensions that are shown in the assembly position (A), where the extensions are closely aligned with the pronged terminals, where a first arcuate conductive articulable extension is pivotally attached to the first pronged terminal, and a second arcuate conductive articulable extension is pivotally attached to the second pronged terminal; 
         FIG. 6 b    is a frontal view of the modified circuit breaker shown in the use position (U), wherein the arcuate conductive articulable extensions are pivotally rotated out board to a use position where the articulable extensions are nearly orthogonal to the pronged terminals, and closely aligned as to be nearly longitudinal; 
         FIG. 6 c    is an exploded view of an articulable extension, a pronged terminal, and a rivet; 
         FIG. 7 a    is a plan view of a front side of the adapter&#39;s electrical insulating chute shaped housing, that insulates and supports the modified circuit breaker and the housing has accessible open cavities that are sufficiently large to accommodate springedly widened clips gripping articulable extensions in the use position; 
         FIG. 7 b    is an overhead view of a top side of the adapter&#39;s housing illustrating the approximate size and position of the sockets that receive the pronged terminals fitted with articulatable extensions; 
         FIG. 7 c    is a plan view of a bottom side of the adaptor&#39;s electrical insulating chute shaped housing illustrating the accessible open cavities; and 
         FIG. 7 d    is a cross-sectional view of the chute shaped housing, taken along sectional line  7   d - 7   d  of  FIG. 7 a   , illustrating how the pivoting action transitions (T) from an assembly position (A) to a use position (U) places positions articulatable extensions in the accessible open cavity and the action effectively locks the modified circuit breaker on the housing. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invented adapter enables a circuit breaker to be installed in place of a conventional fuse in a conventional fuse holder. In an exemplary embodiment, the circuit breaker has planar pronged terminals that protrude from a side of the circuit breaker. The circuit breaker has a thickness that is narrow enough to fit in a bay of a fuse holder. The prior art, as shown in  FIG. 1 , illustrates a conventional fuse holder  100  that may hold up to three fuses  120  (see  FIG. 2 ), and in the instant case the holder has two fuses. In the illustrated fuse holder, there are only two fuses  120   a , 120   b  in the holder  100  so that the reader can better understand the art. The fuse holder  100  has three bays  110   a , 110   b , 110   c . The outside bays  110   a ,  110   c  are nearly mirror images, differing only in the location of the fuse holder fastening hole  102  in the base plate  104 . Outside bay  110   a  has an upper left insulator  115   a   1  and a lower left insulator  116   al . Outside bay  110   c  has an upper right insulator  115   cr  and a lower right insulator  116   al . Bays  110   b  and  110   c  share an upper left insulator  115   c   1  and a lower left insulator  116   c   1 . Bays  110   a  and  110   c  share an upper right insulator  115   cr  and a lower right insulator  116   cr . Each bay has a width that is about  110   w . In the applicant&#39;s illustrated invention there is additional insulation for each bay, and the additional insulation is not shared, irrespective of the number of fuse bays. 
     In the illustrated fuse holder  100  bay  110   c  has two clamping clips  111   c ,  112   c  that are ready to receive the fuse  120  with knife-blade-ends  121 , 122  ( FIG. 2 ). Both of the clamping clips  111   c , 112   c  are springedly closed. In the other two bays  110   a , 110   b  the clips  112   a ,  111   a  and  112   b ,  111   b  are gripping and securing fuses  120   a , 120   b . The clips  112   a ,  111   a  and  112   b ,  111   b  are springedly widened. In the case of clips  112   a ,  111   a  and  112   b ,  111   b  the fuses&#39; blade sections  121   a , 122   a , 121   b , 122   b  have a thickness that determines how far the clips  112   a ,  111   a  and  112   b ,  111   b  are widened. Widening causes the clips to tighten their grip on the blade elements. 
     The fuse  120  shown in  FIG. 2  and  FIG. 1  has a blade element  124  with sections  121 , 122 . The illustrated fuse may be an SCR fuse. It includes a center section  123  which is substantially an elongate cylindrical element. The outboard elongate sections  121 , 122  are similar in shape to a blade. The blade element has an overall length  1201  that extends lengthwise through the cylindrical element. The blade element  124  has a center fusible portion that is enclosed within the cylindrical element  123 , which may be made of glass. 
     The fuse may be replaced by an inventive circuit breaker adapter shown in  FIG. 3 , where the circuit breaker adapter may be utilized in a fuse holder. In an exemplary embodiment, the circuit breaker adapter  10  includes a modified circuit breaker and a housing  20  with a bottom that may receive the fuse holder clips. The modified circuit breaker  51  is seated in a chute section of the housing  20 . The chute portion of the housing  20  has a right wall  25 ′, a left wall  25 , a right ledge  22   s ′, a left ledge  22   s , a lower second right wall  25   s ′, a lower second left wall  25   s , and a floor  22   f . A bottom side  58  of the modified circuit breaker  50  is supported by the chute&#39;s right ledge  22   s ′ and the chute&#39;s left ledge  22   s , spanning a lower channel  22   c  having a floor  22   f  (see  FIG. 7 a   ). A portion of the circuit breaker&#39;s left wall  56  is lodged against the chute&#39;s left wall  25 , and a portion of the circuit breaker&#39;s right wall  56 ′ is lodged against the chute&#39;s right wall  25 ′. The circuit breaker has a reset button  52 . 
     As shown in  FIG. 6 b   , the illustrated circuit breaker is held together with rivets  53 ,  53 ′ and  53 ″. As shown in  FIG. 3 , rivet assembly  53 ″ extends below the front plate  55  from the bottom side  58  into the lower channel  22   c . The rivet assembly  53 ″ extends between the lower second right wall  25   s ′ and the lower second left wall  25   s  toward the floor  22   f  of the chute. 
       FIG. 4  illustrates the fuse holder shown in  FIG. 1 , which in one exemplary variation is a Bussmann™ sfb1060-03 buss fuse block. The width of a bay  110   w , as shown in  FIG. 1 , and the thickness of the circuit breaker  50   t  are approximately the same. The circuit breaker may be slightly thicker as it is elevated above the fuse holders&#39; insulation walls  115   al - cr ,  116   al - cr . Note, that in  FIG. 4 , in bays  110   a  and  110   b , the circuit breaker adapters  10   a , 10   b  cover the clips. Only clips  111   c ,  112   c  are visible, and ready to receive the circuit breaker adapter  10   c  (not specifically shown). 
     A frontal view of the circuit breaker adapter having a modified circuit breaker is shown in  FIG. 5 . 
     As illustrated in  FIG. 6 a   , a circuit breaker is modified to have extensions  70 , 70 ′. Brass is known to be suitable material. After modification the circuit breaker is renumbered to  51  reflecting the modifications. The modifications result in a pivotally attached first arcuate conductive articulable extension  70  to the first pronged terminal  60 , and a pivotally attached second arcuate conductive articulable extension  70 ′ to the second pronged terminal  60 ′. An exploded view is shown in  FIG. 6 c    of second arcuate conductive articulable extension  70 ′. The articulable extension  70 ′ is broadly similar to the fuse blade sections  121 , 122   a  shown in  FIG. 2 , however there are major departures. In  FIG. 6 c   , the articulable extension  70 ′ has a length  70   l ′, a thickness  70   t ′, an inboard hole  77 ′ near an inboard end  76 ′ adjacent to an acruate edge  74 ′, a beveled corner  75 ′, and a tapered edge  72  that extends from the inboard end  76 ′ to an outboard end  71 ′. The inboard hole  77 ′ is axial to a terminal hole  62 ′ in the pronged terminal  60 ′. A fastening element  80 ′ axially connects the extension  70 ′ and the terminal  60 ′, permitting friction rotation. 
     Returning to  FIG. 6 a   , extension  70  is similarly attached to terminal  60 . The length between the points of attachment is  80  to  80 ′ is indicated by  601 . This length is a separation length, which is about the distance between the center points  27   c ,  27   c ′ of sockets  27 ,  27 ′ as illustrated in  FIG. 7 b   . As shown in  FIG. 6 b   , the arcuate corners  74 , 74 ′ permit rotation of the extensions  70 , 70 ′ without impinging either the bottom side  58  or the rivet assembly  53 ″ of the circuit breaker. As shown in  FIG. 6 a   , the extensions  70 , 70 ′ are in the assembly position (A). 
     In  FIG. 6 b   , the articulable extensions  70 , 70 ′ are in the use position (U). When an extension is rotated in the socket  27 , 27 ′ during the transition (T) the corner  75 , 75 ′ of the extension  70 , 70 ′ could impact the wall  25   s , 25   s ′(see  FIG. 7 a   ) or a wall  29 , 29 ′ in the accessible open cavity as shown in  FIG. 7 d   . To prevent impact, the corners  75 , 75 ′ may be beveled to a point where they are rounded. 
       FIG. 6 b    illustrates the modified circuit breaker  51  with the extensions in the use position. The housing  20  would normally prevent this view. 
     The adaptor&#39;s electrical insulating chute shaped housing  20  is illustrated in  FIG. 7 a   . The housing  20  insulates and supports the modified circuit breaker  51  (not shown-see  FIG. 6 b   ). The housing has a left top side  22 , a right top side  22 ′, a left end side  23 , a right end side  23 ′, a bottom side  26 , a center chute shaped section that includes a chute section&#39;s right side  25 ′, a chute section&#39;s left side  25 , a right ledge  22   s ′, a left ledge  22   s , a channel section having a lower second right side  25   s ′, a lower second left side  25   s , and a floor  22   f . As shown in  FIGS. 7 c  and 7 d   , the housing has accessible open cavities (left cavity  28  and a right cavity  28 ′), where the right cavity  28 ′ is shown in  FIG. 7   d.    
     The modified circuit breaker  51  is attached by simply plugging the pronged terminals fitted with extensions (see  FIG. 6 a   ) into sockets. The sockets  27 , 27 ′ are shown in  FIG. 7 b   . The center points of the sockets  27   c , 27   c ′ are labeled. The sockets are located in the ledges  22   s , 22   s ′, and the sockets are sufficiently large to accommodate the terminals with fastened extensions. 
     The sockets extend to the accessible open cavities  28 , 28 ′, as shown in the plan view of the bottom  26  side of the housing  20 . The cavities  28 , 28 ′ are sufficiently large to accommodate the springedly widened clips  111   c ,  112   c  gripping the articulable extensions  70 , 70 ′ in the use position. 
     Rotation of the extensions  70 , 70 ′ and one of the cavities  28 ′ is shown in  FIG. 7 d   , which is a cross-sectional view of the housing, taken along sectional line  7   d - 7   d  of  FIG. 7 a   . The  FIG. 7 d    illustrates how the pivoting action from the assembly position (A) through transitions (T) to the use position (U). The action effectively locks the modified circuit breaker  51  on the housing  20 . As may be easily seen, once in the use position the tapered edge  72  is ready to engage a clip. The extension cannot rotate any further as the end of the extension  76  limits movement as does the ceiling  29   c , 29   c ′ of the cavities. Once engaged with the clips  111   c ,  112   c , the springedly tensioned clips restrain any further movement. The adapter  10  is secured in a fused holder and the modified circuit breaker  51  is in electrical contact through the extensions  70 ,  70 ′, which are secured in the clips  111   c ,  112   c . The clips  111   c ,  112   c  are individually and completely surrounded by an insulating housing. The housing may be made of Nylon® or other suitable material. 
     Finally, any numerical parameters set forth in the specification and attached claims are approximations (for example, by using the term “about”) that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of significant digits and by applying ordinary rounding.