Patent Publication Number: US-9425017-B2

Title: Method of manufacturing a complex fusible link

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 13/279,887, filed Oct. 24, 2011, which is a divisional application of U.S. patent application Ser. No. 12/550,037, filed Aug. 28, 2009, which claims priority from Japanese Patent Application No. 2008-228578 filed on Sep. 5, 2008, and the entire subject matters of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates to a complex type fusible link having a plurality of fusible elements, a fuse box and a manufacturing method thereof. 
     BRIEF DESCRIPTION OF THE RELATED ART 
     One related fuse box for being directly mounted on a battery is disclosed, for example, in JP-A-2000-195408. More specifically, this fuse box includes a plurality of blade fuses, and a synthetic resin box on which blade fuse-mounting portions are provided by blocking out. An input terminal for connection to the battery is beforehand mounted in the box, and is exposed at one side portions of the mounting portions. Each blade fuse is mounted in the corresponding mounting portion of the box, and one end of the blade fuse is screw fastened to the input terminal, while an LA terminal press-clamped to a wire is screwfastened to the other end of the blade fuse. In this fuse box, however, particularly the blade fuses are provided as separate single parts, and therefore is individually mounted and screw-fastened, and this mounting or assembling operation has been rather cumbersome. 
     Therefore, in order to mainly improve the mounting or assembling efficiency, there has been proposed a fuse device of the type in which input and output terminals and fuse elements are formed integrally with each other. Namely, one bus bar is press-worked to provide an integral or one-piece structure including an input terminal portion, a plurality of tab-like output terminals and a plurality of fuse elements each interconnecting the input terminal portion and the corresponding output terminal portion, and then a resin-molded portion is formed around the fuse elements such that the fuse elements are exposed. This fuse device is received within a box, and the input terminal portion is connected to a battery, while mating terminals each fixedly secured to an end portion of a wire are fittingly connected respectively to the output terminals, and in this condition the fuse device is used. 
     In this fuse device, when an electric current of above a predetermined level flows through a circuit connected to any of the output terminals, the corresponding fuse element melts. In this case, there is a possibility that debris resulting from the melted fuse element is scattered, and deposits on other fuse elements to cause such other fuse elements to unnecessarily melt. Therefore, it has been desired to further improve the fuse device. 
     Therefore, as shown in  FIG. 14 , there has been proposed a structure in which vertically-extending ribs  103  and  103 A each disposed between adjacent fuse elements  102  are formed on opposite (front and rear) faces of a resin-molded portion  101  of a fuse device  100 , and partition walls  203  each having a fitting groove  202  at its widthwise central portion are formed on opposed walls or surfaces of an insertion space  201  of a box  200 , and the ribs  103  can be fitted in the respective fitting grooves  202 , while distal ends of the ribs  103 A of a larger projecting height can be fitted respectively in vertically-extending guide grooves  204  (see, for example, JP-A-2002-358866). In this fuse device  100 , any two adjacent fuse elements  102  are perfectly separated or isolated from each other by the ribs  103 ,  103 A and the partition wall  203  which serve as protection walls, and therefore even when any of the fuse elements  102  melts, debris resulting from the melted fuse element  102  is prevented from being scattered toward other fuse elements  102 , thus preventing such other fuse elements  102  from unnecessary melting. 
     In this related fuse device, with respect to the integral construction having the connecting plate portion, the fusible element portions and the output (connector) portions, there is usually a dimensional difference between the required pitch of arrangement of the fusible elements and the pitch of the output portions limited or required by the configuration of the connector. Therefore, in the case of producing the component parts of the fuse device and for example, in a method of forming these parts by press-cutting, a yield is lowered. Namely, when the press-cutting (hollowing) operation is performed in accordance with the required pitch of arrangement of the fusible elements, there is encountered a disadvantage that a complicated or wasteful arrangement is made so as to meet a special design of the output connector or a demand of the output side. 
     SUMMARY 
     the present invention has been made in view of the above circumstances, and an object of the invention is to provide a complex type fusible link, a fuse box and a manufacturing method thereof, in which the fusible link can be manufactured in such a manner that its performance corresponding to a selected one of various types for use with this fusible link can be meticulously set, and besides a yield of a bus bar can be enhanced. 
     The first aspect of the invention is a complex type fusible link which includes an insulative block base including a plurality of cavities; a conductive connecting plate which is integrally embedded in the insulative block base, a part of the conductive connecting plate being exposed to at least one of the cavities; a plurality of fusible elements each of which is accommodated in corresponding one of the cavities and includes a first end which is connected to the part of the conductive connecting plate and a second end; and a plurality of terminals each of which is integrally embedded in the insulative block base and includes a first end which is connected to the second end of corresponding one of the fusible elements and a second end which is exposed from the insulative block base. 
     In the complex type fusible link according to the first aspect of the invention, suitable materials and suitable material thicknesses are selected for the connecting plate portion, the output portion and the fusible elements, and by doing so, a compact design and a low-cost design can be achieved. Also, the complex type fusible link can be manufactured in such a manner that its performance corresponding to a selected one of various types for use with this fusible link can be meticulously set, and besides a yield of a bus bar can be enhanced. 
     The second aspect of the present invention is a complex type fusible link according to the first aspect, in which the first and the second end of at least one of the fusible elements are distant in a direction perpendicular to the conductive connecting plate. 
     In the complex type fusible link according to the second aspect of the invention, at least one fusible element, when viewed obliquely from the upper side of the exterior, can be visually confirmed clearly, and therefore whether or not each fusible element is melted can be easily confirmed with the eyes. 
     The third aspect of the present invention is a complex type fusible link according to the first or the second aspect, in which at least one of the fusible elements includes a fastening portion to which an another fusible element is fastened. 
     In the complex type fusible link according to the third aspect of the invention, when any of the fusible elements melts, a new fusible element can be easily attached to this melted fusible element, utilizing the fastening means. Therefore, a cumbersome operation, for example, for connecting wires to the new fusible element is not necessary. 
     The fourth aspect of the present invention is a complex type fusible link according to the first, the second or the third aspect, in which the block base has a fin. 
     In the complex type fusible link according to the fourth aspect of the invention, a heat radiating effect can be enhanced by the fin portion. 
     The fifth aspect of the present invention is fuse box which includes a complex type fusible link including: an insulative block base including a plurality of cavities; a conductive connecting plate which is integrally embedded in the insulative block base, a part of the conductive connecting plate being exposed to at least one of the cavities; a plurality of fusible elements each of which is accommodated in corresponding one of the cavities and includes a first end which is connected to the part of the conductive connecting plate and a second end; and a plurality of terminals each of which is integrally embedded in the insulative block base and includes a first end which is connected to the second end of corresponding one of the fusible elements and a second end which is exposed from the insulative block base, wherein the first and the second end of at least one of the fusible elements are distant in a direction perpendicular to the conductive connecting plate; and a transparent cover which covers the complex fusible link from outside thereof. 
     In the fuse box according to the fifth aspect of the invention, suitable materials and suitable material thicknesses are selected for the connecting plate portion, the output portion and the fusible elements of the complex type fusible link, and by doing so, the compact design and the low-cost design can be achieved, and also the complex type fusible link can be manufactured in such a manner that its performance corresponding to a selected one of various types for use with this fusible link can be meticulously set, and besides the yield of the bus bar can be enhanced. 
     The sixth aspect of the present invention is a manufacturing method of a complex fusible link which includes: a hollowing process to hollow out a conductive plate into a link-like conductor including a connecting plate and a terminal; a cutting out process to cut out the link-like conductor so as to separate the connecting plate and the terminal; an insert molding process to form a block base including a cavity after setting the connecting plate and the terminal in a mold; and a connecting process to electrically connect a fusible element to the cavity. 
     In the complex type fusible link-manufacturing method according to the sixth aspect of the invention, suitable materials and suitable material thicknesses are selected for the connecting plate portion, the output portion and the fusible elements of the complex type fusible link, and by doing so, the compact design and the low-cost design can be achieved, and also the complex type fusible link can be manufactured in such a manner that its performance corresponding to a selected one of various types for use with this fusible link can be meticulously set, and besides the yield of the bus bar can be enhanced. 
     According to the above mentioned one or more illustrative aspects of the present invention, the compact design of the complex type fusible link can be achieved, and the complex type fusible link can be manufactured in such a manner that its performance corresponding to a selected one of various types for use with this fusible link can be meticulously set, and besides the yield of the bus bar can be enhanced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a front-elevational view of a first exemplary embodiment of a fuse box of the present invention, and  FIG. 1B  is a side-elevational view thereof as seen from a right end face thereof. 
         FIG. 2A  is a plan view of the fuse box, and  FIG. 2B  is a bottom view thereof. 
         FIG. 3  is an exploded perspective view of the fuse box. 
         FIG. 4  is a wiring diagram of the fuse box. 
         FIGS. 5A to 5D  are views showing steps of a method of manufacturing the fuse box. 
         FIG. 6  is a plan view of a link-like conductor used in the manufacture of the fuse box. 
         FIG. 7  is an exploded perspective view of a second exemplary embodiment of a fuse box of the invention. 
         FIG. 8A  is a front-elevational view of the fuse box of the second embodiment, and  FIG. 8B  is a side-elevational view thereof as seen from a right end face thereof. 
         FIG. 9  is a perspective view of a fusible element used in a complex type fusible link of the fuse box of the second embodiment. 
         FIG. 10  is a front-elevational view of a third exemplary embodiment of a complex type fusible link of the invention. 
         FIG. 11  is an exploded perspective view of the complex type fusible link of the third embodiment. 
         FIG. 12A  is a plan view of a fusible element used in the complex type fusible link of the third embodiment, and  FIG. 12B  is a side-elevational view thereof. 
         FIGS. 13A and 13B  are views explanatory of an operation of the third embodiment. 
         FIG. 14  is an exploded perspective view of a related fuse device. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION 
     Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
     First Exemplary Embodiment 
       FIGS. 1 to 3  show a fuse box HB comprising a first exemplary embodiment of a complex type fusible link  10  of the invention and a cover  20  fitted on the complex type fusible link  10 . The fuse box HB is installed in a power box (not shown) of a vehicle. The complex type fusible link  10  includes a block base portion  11 , an connecting plate portion  12 , fusible elements  13 , terminals  14 , and a fin portion F. 
     The complex type fusible link  10  is constructed as a fuse device (for electronic parts mounted on the vehicle) disposed between a bus bar (forming the connecting plate portion  12 ) for connection to a battery mounted on the vehicle and electrically-connecting portions (forming the terminals  14 ) for connection to wires (wire harness) connecting the various electronic parts (hereinafter referred to as “electrical equipments”) to the battery. In this embodiment, the complex type fusible link  10  is mounted within the vehicular power box as described above. 
     The block base portion  11  is formed of an insulative resin, and the connecting plate portion  12  and the terminals  14  are mostly embedded in the block base portion  11  by insert molding. Fusible element-receiving portions  11 A to  11 G (each in the form of a recess and one exemplary embodiment of cavities) for respectively receiving the fusible elements  13  (described later) are formed in the block base portion  11 , and also the fin portion F having a number of air-cooling fins for promoting the radiation and dissipation of Joule heat generated from the connecting plate portion  12  and the terminals  14  is formed integrally on the block base portion  11 . Recess portions  111  and  112  for the screw fastening of LA terminals (not shown) are formed respectively at opposite (left and right) end portions of the block base portion  11 . 
     Further, a female type connector CN to which a male type connector (connected to the wires (wire harness) for connecting the electrical equipments respectively to terminals c to f (described later)) can be connected is formed integrally on the block base portion  11 . Connector chambers  11 H to  11 J are formed in the connector CN. 
     The connecting plate portion  12  is made of an electrically-conductive material such as a metal plate, and is integrally embedded in the block base portion  11 , with its opposite end portions (terminals a and o) exposed. This connecting plate portion  12  forms the bus bar. Holes are formed respectively through the opposite end portions of the connecting plate portion  12 , and wire-connected terminals (LA terminals, that is, ring terminals) are adapted to be screw fastened to these holes, respectively. 
     More specifically, in this embodiment, the connecting plate portion  12  is divided into two plate portions which are electrically interconnected by the fusible element h. One (hereinafter referred to as “first connecting plate portion  12 A) of the two plate portions is integrally embedded in the block base portion  11  by insert molding or other means, with a tongue-like metal portion (end portion)  12 C (forming the terminal a for connection to the LA terminal) exposed. Also, the other plate portion (hereinafter referred to as “second connecting plate portion  12 B) is integrally embedded in the block base portion  11  by insert molding or other means, with a tongue-like metal portion (end portion)  12 D (forming the terminal o for connection to the LA terminal) exposed. 
     The fusible elements  13  are mounted or received respectively in the fusible element-receiving portions  11 A to  11 G formed at the block base portion  11 . Each fusible element  13  melts upon flowing of an over-current of a predetermined level therethrough, thereby protecting the corresponding electrical equipment. The fusible elements  13  are so mounted in the respective fusible element-receiving portions  11 A to  11 G that when any of these fusible elements  13  melts, it can be replaced with a new one. In this embodiment, seven kinds of fusible elements  13  (that is, the fusible elements h to n) are mounted in the fusible element-receiving portions  11 A to  11 G, respectively. 
     In  FIG. 1 , the terminals  14  comprise two LA terminal connecting-purpose terminals  14 A and  14 B exposed to one face of the block base portion  11 , and four connector connecting-purpose terminals  14 C,  14 D,  14 E and  14 F embedded in the block base portion  11  such that their one end portions (lower end portions) are exposed at the respective connector chambers  11 H,  11 I and  11 J formed at a lower portion of the block base portion  11 . Like the connecting plate portions  12 A and  12 B, the terminals  14 A and  14 F are mostly embedded integrally in the block base portion  11 , and therefore these terminals  14 A to  14 F are insert molded in the block base portion  11 . The other end portions (upper end portions in  FIG. 1 ) of the terminals  14 A and  14 B are exposed respectively at the fusible element-receiving portions  11 B and  11 G, and the other end portions (upper end portions) of the terminals  14 C to  14 F are exposed respectively at the fusible element-receiving portions  11 C to  11 F. 
     Therefore, in this embodiment, suitable materials and suitable material thicknesses can be properly selected for the connecting plate portions  12 A and  12 B, the terminals  14  and the fusible elements  13 , and therefore a compact design and a low heat-generating design can be easily achieved. Particularly, the complex type fusible link can be manufactured in such a manner that its performance corresponding to a selected one of various types for use with this fusible link can be meticulously set, and besides the yield of the bus bar can be enhanced. 
     Next, a method of manufacturing the complex type fusible link  10  of this embodiment will be described. 
     As shown in  FIG. 5 , the method of manufacturing the complex type fusible link  10  of the invention includes a first step S 1  of hollowing from a metal plate a link-like conductor  15  (see  FIG. 6 ) of an integral or one-piece construction corresponding to the connecting plate portion  12  and the terminals  14 , a second step S 2  of severing or separating the connecting plate portions  12 A and  12 B and the terminals  14  of the link-like conductor  15  from one another, a third step S 3  of setting the separated connecting plate portion  12  and terminals  14  in a mold and effecting an insert molding operation to form the block base portion  11  serving as the body portion of the complex type fusible link, and a fourth step S 4  of mounting the fusible elements  13  respectively in the fusible element-receiving portions  11 A to  11 G of the block base portion  11  in an electrically-connected condition. 
     In the first step S 1 , the intermediate product sheet (hereinafter referred to as “link-like conductor”)  15  of an integral or one-piece construction is hollowed from the predetermined metal plate (for example, a metal plate of a generally rectangular shape shown in  FIG. 6 ) by pressing or other means. 
     In the second step S 2 , the connecting plate portion  12  of the link-like conductor  15  of  FIG. 6  is cut at its central portion along a line L 1  to be divided into two connecting plate portions  12 A and  12 B. The terminals  14 A,  14 C and  14 D are integrally connected with the connecting plate portion  12 A through respective thread-like interconnecting portions, while the terminals  14 E,  14 F and  14 B are integrally connected with the connecting plate portion  12 B through respective thread-like interconnecting portions, and therefore these thread-like interconnecting portions are cut along a line L 2 . Further, in order that a rectangular portion S of the connecting plate portion  12 A can form a step portion, that is, can be disposed perpendicularly to the sheet of  FIG. 6 , the connecting plate portion  12 A is right-angularly bent into a generally inverted V-shape along a line LA ( FIG. 6 ), and then is right-angularly bent into a generally V-shape along a line LB to form a right-angular crank-shape. The other connecting plate portion  12 B is bent perpendicularly downwardly from the sheet of  FIG. 6  along a line L 3 , that is, bent into a generally inverted V-shape. In this embodiment, although the order of the above cutting (or severing) operations and the above bending operations are not particularly determined, it is preferred that the order be so determined that these operations can be carried out efficiently. 
     In the third step S 3 , the connecting plate portions  12 A and  12 B and the terminals  14 A to  14 F (which have been separated from one another in the second step S 2 ) are set in the mold (not shown), and then a predetermined insulative resin is injected or poured into the mold, thereby effecting the insert molding operation. As a result, the block base portion  11  having the connecting plate portions  12 A and  12 B and the terminals  14 A to  14 F integrally embedded therein (in such a manner that part of each of these portions is exposed) is obtained. In the insert molding of the block base portion  11 , the two connecting plate portions  12 A and  12 B and the six terminals  14 A to  14 F are set in the predetermined mold in such a manner that they are positioned and arranged in a manner shown in  FIG. 5B . Namely, these inserts are arranged with their outer edges coinciding with longitudinal and transverse reference lines LX, LY 1  and LY 2 , and merely by doing so, the inserts can be accurately positioned. 
     The fusible element-receiving portions  11 A to  11 G (each in the form of a recess) for respectively receiving the fusible elements are formed in the one face (front face in  FIG. 5C ) of the thus obtained block base portion  11 , and are arranged at predetermined pitches in generally closely spaced relation to one another, and the three connector chambers  11 H to  11 J are formed in the lower portion ( FIG. 5C ) of the one face of the block base portion  11  in adjoining relation to one another (The connector chambers  11 H to  11 J do not always need to be arranged at the same pitch). The recess portions  111  and  112  are formed in the block base portion  11 , and projections  111 A and  112 A projecting respectively into holes of the terminals  14 A and  14 B exposed to the front face (in  FIG. 5C ) (in which the fusible element-receiving portions  11 A to  11 G are formed) are formed within the recess portions  111  and  112 , respectively. After the complex type fusible link is completed, the LA terminals (not shown) are mounted in the recess portions  111  and  112 , respectively. 
     In the fourth step S 4 , the fusible elements  13  beforehand prepared through pressing, wire cutting, laser cutting, etching or other means are electrically connected respectively to the fusible element-receiving portions  11 A to  11 G of the block base portion  11  molded in the third step S 3 . Each fusible element  13  has proper fuse characteristics (rating) so that an optimal maximum allowable current can flow at the corresponding fusible element-receiving portion  11 . 
     One side edge portions of the connecting plate portions  12 A and  12 B and the end portions of the terminals  14 A to  14 F are exposed at the corresponding fusible element-receiving portions  11 , and these side edge portions and end portions are connected to the corresponding fusible elements  13  received in the respective fusible element-receiving portions  11 . The fusible elements  13  can be connected to these portions by any suitable method such as ultrasonic welding and laser beam welding. As a result, the link type fuse unit having a plurality of fuse circuits (see  FIG. 4 ), that is, the complex type fusible link  10 , is formed. When the cover  20  is fitted on this complex type fusible link  10 , the fuse box HB shown in  FIGS. 1 and 2  is completed. 
     In the method of manufacturing the complex type fusible link  10  of this embodiment, when the block base portion  11  is to be insert molded, the inserts, that is, the two connecting plate portions  12 A and  12 B and the six terminals  14 A to  14 F, are set in the predetermined mold in such a manner that they are positioned and arranged in the manner shown in  FIG. 5B . Namely, these inserts are arranged with their outer edges coinciding straight with the longitudinal and transverse reference lines LX, LY 1  and LY 2 , and merely by doing so, the inserts can be accurately positioned. 
     In the method of manufacturing the complex type fusible link  10  of this embodiment, the terminals  14  and the connecting plate portion  12  are formed by the press-cutting (hollowing) of one metal plate, whereas the fusible elements  13  are manufactured separately from the terminals  14  and the connecting plate portion  12 . The arrangement of the terminals  14 C to  14 F received in the respective connector chambers  11 H to  11 J is limited by the configuration of the connector, and therefore it is difficult to cause the pitch of arrangement of the fusible elements  13  to coincide with the pitch of arrangement of the connector chambers (that is, the pitch of the terminals  14 A to  14 F). Therefore, in the case where the terminals  14  are hollowed from one metal plate in integrally-connected relation to the fusible elements  13 , wasteful areas which can not be used as the fusible elements  13  and the terminals  14  much develop because of the difference in the pitch between the terminals  14  and the fusible elements  13 . In this embodiment, however, only the connecting plate portion  12  and the terminals  14  are formed separately from the fusible elements  13 , and therefore such wasteful areas which can not be used will not develop, and this is economical. In addition, in case the terminals  14 A to  14 F and the connector chambers  11 H to  11 J are arranged in accordance with the pitch of arrangement of the fusible elements, there is encountered a disadvantage that a complicated or wasteful arrangement is made so as to meet a special design of the connector (output) side or a demand of the output side. In this embodiment, however, the terminals are formed separately from the fusible elements, and therefore such a disadvantage will not be encountered. 
     Second Exemplary Embodiment 
     Next, a second exemplary embodiment of the invention will be described with reference to the drawings. 
       FIGS. 7 and 8  show a fuse box HB comprising a complex type fusible link  30  of the second exemplary embodiment and a transparent cover  40  fitted on the complex type fusible link  30 . This fuse box HB is installed in a power box of a vehicle as in the first embodiment. The complex type fusible link  30  includes a block base portion  31 , a connecting plate portion  32 , fusible elements  33 , and terminals  34 . 
     Unlike the block base portion  11  of the first embodiment, the block base portion  31  of this embodiment dose not have any connector chamber. One end portions of terminals forming the terminals  34  project outwardly from a lower surface ( FIGS. 7 and 8 ) of the block base portion  11 . That area of the block base portion  31  in which fusible element-receiving portions  31 A are formed is entirely recessed to form a slit (or recess)  31 B recessed one step from a face (front face in  FIG. 7 ) of the block base portion  31 , and the transparent cover  40  is detachably fitted on the block base portion  31 , utilizing this slit (or recess)  31 B. A recess  311  for the screw fastening of an LA terminal (not shown) is formed in one end portion of the block base portion  31 , and one end portion  32 B of the connecting plate portion  32  is exposed at this recess  311 . 
     One side edge portion  32 A (see  FIG. 8 ) of the connecting plate portion  32  is exposed at the fusible element-receiving portions  31 A of the block base portion  31  as in the first embodiment, and the one end portion  32 B (see  FIG. 8 ) thereof is exposed at the LA terminal-mounting recess  311  of the block base portion  31 . As shown in  FIG. 8 , the connecting plate portion  32  is embedded in the block base portion  31  such that an embedding position of the connecting plate portion  32  is lower by an amount (height) d than an embedding position of the terminals  34  in a direction of the thickness of the block base portion  31 . 
     In order that whether or not each fusible element  33 , incorporated in the fuse box HB of  FIG. 8  and hence received in the corresponding fusible element-receiving portion  31 A, is melted can be easily confirmed with the eyes from an upper side of the exterior, an intermediate fusible portion  333  of each fusible element  33  is inclined at an angle θ such that two joint portions  331  and  332  formed respectively at the opposite ends of the fusible element  33  are different in height by an amount d from each other. The joint portion  331  is connected to the one side edge portion  32 A of the connecting plate portion  32  exposed at the fusible element-receiving portion  31 A. On the other hand, the joint portion  332  is connected to the other end portion of the corresponding terminal (the terminal portion  34 ) exposed at the fusible element-receiving portion  31 A. 
     Therefore, even when the fuse box HB of this embodiment is surrounded by various adjacent parts, the fusible elements  33  received in the respective fusible element-receiving portions  31 A (covered with the transparent cover  40 ) can be easily visually recognized through the transparent cover  40 . Particularly, this fusible element  33  is formed into the inclined or slanting condition, and therefore even when the fusible element  33  is received in the recess-like fusible element-receiving portion  31 A, the lower joint portion  332  projects more toward the front face of the block base portion  31  than the upper joint portion  331 , and the intermediate fusible portion  333  is spaced apart from the bottom surface of the fusible element-receiving portion  31 A, and therefore whether or not the fusible element  33  is melted can be easily confirmed from the exterior. 
     Although a method of manufacturing the complex type fusible link  30  of this embodiment is almost similar to the method of manufacturing the complex type fusible link  10  of the first embodiment, the former method differs from the latter method in that in the insert molding, the connecting plate portion  32  and the terminals  34  are set in a mold in such a manner that the height of the terminals  34  is larger by the amount d than the height of the connecting plate portion  32 . 
     Third Exemplary Embodiment 
     Next, a third exemplary embodiment of the invention will be described with reference to the drawings. 
       FIGS. 10 and 11  show a third exemplary embodiment of a complex type fusible link  50 , and this fusible link is installed in a power box of a vehicle as in the first embodiment. The complex type fusible link  50  includes a block base portion  51 , a connecting plate portion (not shown), fusible elements  53 , and terminals  54 . In the drawings, reference numeral  55  denotes spare blade fuses. 
     Like the block base portions of the first and second embodiments, the block base portion  51  is formed into a thin plate-shape or a box-shape, using an insulative resin, and fusible element-receiving portions  51 A are formed in a central portion of one face of the block base portion  51 , and are arranged at a predetermined pitch in relatively closely-spaced relation. One side edge portion  52 A (see  FIG. 11 ) of the connecting plate portion is exposed at the fusible element-receiving portions  51 A, and also one end portions  54 A of the terminals  54  are exposed at the fusible element-receiving portions  51 A, respectively. 
     A recess  51 B for the screw fastening of an LA terminal (not shown) is formed in the one face of the block base portion  51  at one end portion thereof as described above for the block base portion of the second embodiment, and one end portion  52 B of the connecting plate portion is exposed at the recess  51 B. On the other hand, a step portion  51 C for receiving the blade fuses  55  is formed in the one face of the block base portion  51  at the other end portion thereof. The spare blade fuses  55  are fixed to this step portion  51 C. 
     Female type connectors CN 1  to CN 4  are formed at one side surface (lower surface) of the block base portion  51 . Connector chambers  51 D to  51 G are formed within the connectors CN 1  to CN 4 , respectively, and the other end portions  54 B of the terminals  54  project into the connector chambers  51 D to  51 G in an exposed manner. 
     The connecting plate portion and the terminals are mostly embedded integrally in the block base portion  51  by insert molding as in the second embodiment. The end portions, etc., of the connecting plate portion and the terminals are exposed to the exterior from the block base portion  51  so as to be electrically connected to the LA terminal and the fusible elements  53  as described above. Namely, with respect to the connecting plate portion, the one side edge portion  52 A (see  FIG. 11 ) for being connected to joint portions  531  of the fusible elements  53 , as well as the one end portion  52 B (see  FIGS. 10 and 11 ) for connection to the LA terminal, is exposed as described above. With respect to the terminals  54 , the one end portions  54 A (see  FIG. 11 ) for being connected respectively to joint portions  532  of the fusible elements  53 , as well as the other end portions  54 B projecting into the respective connector chambers  51 D to  51 G, are exposed as described above. 
     The fusible element  53  has blades so that when this fusible element  53  melts, a substitute fusible element of another type having equal fuse characteristics (rating) can be connected to the melted fusible element  53  through these blades. Namely, the fusible element  53  of this embodiment includes the joint portions  531  and the  532  for being connected respectively to the one side edge portion  52 A of the connecting plate portion and the one end portion  54 A of the terminal portion  54 , an intermediate fusible portion  533 , a pair of upstanding walls  534  and  535  extending perpendicularly respectively from the joint portions  531  and  532 , and the blades  534 A and  535 A of a generally V-shape (serving as fastening means) formed or notched respectively in upper edges of the upstanding walls  534  and  535 . 
     When the fusible element  53  melts, the above-mentioned spare blade fuse  55  having the same fuse characteristics (rating) as this fusible element  53  is fastened to the blades  534 A and  535 A to extend therebetween. By doing so, an operation for exchanging the melted fusible element  53  can be rapidly and easily effected. Therefore, the spare blade fuses  55  equal in fuse characteristics respectively to all kinds of fuses of the fusible elements  53  are provided at the step portion  51 C of the block base portion  51  of the block base portion  51  as described above. The spare blade fuse  55  has an overall length X generally equal to the distance X (see  FIG. 12 ) between the blades  534 A and  535 A. In this embodiment, although the spare blade fuse can be attached to the fusible element by the use of the V-shaped blades, the invention is not particularly limited to this shape and structure, and various modifications can be made. 
     Therefore, in this embodiment, when a cut-off portion  533 A develops in the fusible portion  533  of any of the fusible elements  53 , for example, upon flowing of an over-current therethrough, the spare blade fuse  55  corresponding in fuse characteristics (rating) to this melted fusible element  53  is selected from the spare blade fuses  55  attached to the block base portion  51 , and is removed from this block base portion  51 , and is secured to the melted fusible element  53  while leaving this melted fusible element  53  as it is. Namely, the selected spare blade fuse  55  is press-contacted with the blades  534 A and  535 A formed respectively in the upstanding walls  534  and  535  of the melted fusible element  53 , and thus is fixed thereto, thereby achieving the required electrical connection (see  FIG. 13B ). 
     Therefore, when a fuse melts, for example, during use of the vehicle, it has heretofore been necessary to connect wires to a new fuse replacing the melted fuse, but in this embodiment the relevant fuse circuit can be easily restored with the above simple operation. The complex type fusible link  50  of this embodiment can be manufactured by a method similar to the method of manufacturing the complex type fusible link  10  of the first embodiment. 
     Although this embodiment is directed to the fuse box HB with the complex type fusible link for use in the vehicle, the fusible box HB can be used in other vehicles, vessels and airplanes with various electrical equipments, such as a motor cycle, a pleasure boat, a yacht with an outboard engine or an inboard engine and a small-size airplane.