Patent Publication Number: US-2004056752-A1

Title: Fuse belt and fuse assembling method

Description:
[0001] The present application is based on Japanese Patent Application No. 2002-205988, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002] 1. Field of the Invention  
       [0003] The present invention relates to a fuse belt and a fuse assembling method. More particularly, the invention relates to a fuse belt and a fuse assembling method, which are well suitably used when blade type fuses are automatically assembled into fuse mounting parts of an electric junction box by using an automatic assembling machine.  
       [0004] 2. Related Art  
       [0005]FIG. 9 is a perspective view showing an electric junction box  71  used for protecting various electric systems in a vehicle or the like.  
       [0006] This electric junction box  71  is called a fuse box or a fuse block. A number of fuse mounting parts  72 , which insertionally receive blade type fuses  74 , are arrayed in an upper part of a body case  71   a  made of insulating resin. Connection terminals of various electric systems which will connect to blade type fuses  74  that are inserted into the fuse mounting parts  72 , are housed in the body case  71   a.    
       [0007] The fuse  74  is a blade type fuse, in which a fusible part is provided between a pair of parallel metal flat terminal pieces (referred to as flat terminal pieces)  75   a  and  75   b,  to thereby form a fuse element  75 . A base end (an end containing the fusible part) of the fuse element  75  is placed in an insulating housing  76 .  
       [0008] The blade type fuse  74  is mounted to the fuse mounting part  72  of the electric junction box  71 . The flat terminal pieces  75   a  and  75   b  are electrically connected to the mating terminals of the fuse mounting part  72 .  
       [0009] The assembling of the fuses  74  into the electric junction box  71  is automatized for the purpose of labor saving.  
       [0010] Specifically, an automatic assembling process of the fuses  74  into the electric junction box  71  consists of a fuse supplying step of supplying the fuses  74  to a predetermined fuse supplying position, and an automatic assembling step of assembling the fuses  74 , which have been supplied to the fuse supplying position, to the fuse mounting parts  72  of the electric junction box  71 , which are positioned in a predetermined assembling position.  
       [0011] A part feeder in the conventional fuse supplying step includes a collector part (not shown) for collecting the fuses  74  from a storage part storing a number of the fuses  74 , and a selective transportation part  77  for regulating attitudes of the collected fuses  74  and transporting those regulated fuses  74 . The blade type fuses  74  are transported downstream by vibrating the selective transportation part  77  by a vibrating machine (not shown).  
       [0012] For example, as shown in FIG. 9, in the selective transportation part  77 , the flat terminal pieces  75   a  and  75   b  are supported and guided by a groove  78 , whereby only the fuses  74  having a regular attitude (in which the insulating housing  76  is directed upward) are selected and transported downstream to the fuse supplying position.  
       [0013] The blade type fuses  74  are supplied to the fuse supplying position, and are assembled into the fuse mounting parts  72  of the electric junction box  71  successively and continuously by an assembling robot or the like, in the automatic assembling step.  
       [0014] The blade type fuse  74  is standardized in outer dimensions. Therefore, even if the fuses are different in fuse capacity, the outer dimensions of those fuses are equal.  
       [0015] As described above, in the case that the fuses are fed by means of the part feeder, when a fuse which, for example, is dropped in the assembling place is returned to the storage part, if the fuse is put in another part feeder which handles fuses having fuse capacities being different from that of the dropped fuse, the dropped fuse is fed to another fuse supplying position. As a result, the fuse having the wrong capacity will mistakenly be assembled into the electric junction box  71 .  
       [0016] The fuse  74  which is mistakenly assembled into the electric junction box  71  may be detected in, for example, an electrical conduction inspection carried out after the assembling. In this case, however, the inspection and part replacement work lowers the productivity.  
       [0017] The part feeder which regulates the attitudes of a number of blade type fuses  74  that are fed in different directions is very expensive. Therefore, use of the part feeder increases the cost to construct the equipment for automatizing the fuse assembling work is increased.  
       SUMMARY OF THE INVENTION  
       [0018] An object of the present invention is directed to solve the above problems and to provide a fuse belt and a fuse assembling method which can surely prevent the fuse having the wrong capacity from being mistakenly assembled into the electric junction box, and can automatically assemble fuses without using the part feeder.  
       [0019] According to an aspect of the invention, there is provided a fuse belt comprising: a plurality of fuse elements each having a pair of flat terminal pieces interconnected by a fusible part; insulating housings for holding at least the fusible parts of the fuse elements; and a coupling part for coupling the flat terminal pieces of each fuse element so as to be aligned in a longitudinal direction of the belt.  
       [0020] According to another aspect of the invention, there is provided a fuse assembling method comprising the steps of: forming a plurality of fuse elements, each having a pair of flat terminal pieces and interconnected by a fusible part, and a coupling part for coupling the flat terminal pieces so as to be aligned into one-piece construction by pressing process; attaching each insulating housing covering the fusible part to each fuse element to thereby form a fuse belt; and mounting the fuses to fuse mounting parts of an electric junction box while successively separating the flat terminal pieces of each fuse element in the fuse belt from the coupling part by cutting.  
       [0021] According to a fuse belt and a fuse assembling method of the present invention, when fuses are automatically assembled into fuse mounting parts of an electric junction box by using an automatic assembling machine or the like, fuses are supplied to a predetermined fuse supplying position, in the form of a fuse belt formed with fuse elements having equal capacities being coupled so as to be aligned, and fuses are mounted to the fuse mounting parts of the electric junction box, while being successively separated from the fuse belt by cutting.  
       [0022] Therefore, there is no chance that the fuses having wrong capacities are supplied to the automatic assembling machine or the like. Accordingly, the fuse having the wrong capacity is surely prevented from being mistakenly assembled into the electric junction box.  
       [0023] Fuses are supplied, in the form of a fuse belt, to the automatic assembling machine or the like for assembling fuses into the fuse mounting part of the electric junction box. Since the fuses are uniformly oriented, there is no need of uniformly arranging fuses in their orientation by using an expensive part feeder.  
       [0024] In the fuse assembling method, after the flat terminal pieces of the fuse elements in the fuse belt are successively separated from the coupling part by cutting, the fuses are subjected to an inspection in conductivity, and qualified fuses are mounted to the fuse mounting parts of the electric junction box.  
       [0025] In this case, immediately before the fuses are mounted to the fuse mounting parts of the electric junction box, the fuses may be inspected in conductivity. Therefore, it is prevented that defective fuses are mounted to the fuse mounting parts. Manual work of removing a defect fuse from the fuse mounting part as in the case where fuses are inspected in conductivity in a post-process, is eliminated. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0026]FIG. 1 is a partial cross sectional view showing a fuse belt which is an embodiment of the invention;  
     [0027]FIG. 2 is a partial cross sectional view for explaining a process of manufacturing the fuse belt shown in FIG. 1;  
     [0028]FIG. 3 is a partial cross sectional view for explaining a process of manufacturing the fuse belt shown in FIG. 1;  
     [0029]FIG. 4A is a perspective view of a whole fuse separated from the fuse belt shown in FIG. 1 and FIG. 4B is a partial cross sectional view showing the same;  
     [0030]FIG. 5 is a diagram for explaining a fuse assembling method for assembling fuses into fuse mounting parts of an electric junction box by using the fuse belt shown in FIG. 1;  
     [0031]FIG. 6 is a partial cross sectional view showing a fuse belt which is a second embodiment of the invention;  
     [0032]FIG. 7 is a partial cross sectional view for explaining a process of manufacturing the fuse belt shown in FIG. 6;  
     [0033]FIG. 8A is a perspective view of a whole fuse separated from the fuse belt shown in FIG. 6 and FIG. 8B is a partial cross sectional view showing the same; and  
     [0034]FIG. 9 is a perspective view showing for explaining a conventional fuse assembling method for a fuse into a fuse holder of an electric junction box. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0035] A fuse belt and a fuse assembling method of preferred embodiments of the present invention will be described with reference to the accompanying drawings.  
     [0036]FIG. 1 is a partial cross sectional view showing a fuse belt which is an embodiment of the invention. FIGS. 2 and 3 are each a partial cross sectional view for explaining a process of manufacturing the fuse belt shown in FIG. 1. FIG. 4A is a perspective view of a whole fuse separated from the fuse belt shown in FIG. 1 and FIG. 4B is a partial cross sectional view showing the same. FIG. 5 is a diagram for explaining a fuse assembling method for assembling fuses into fuse mounting parts of an electric junction box by using the fuse belt shown in FIG. 1.  
     [0037] The fuse belt  1  according to the first embodiment, as shown in FIG. 1, is made up of a plurality of fuse elements  7  each having a pair of parallel flat terminal pieces  3  and  4  interconnected by a fusible part  5 , insulating housings  11  for holding at least the fusible parts  5  of the fuse elements  7 , and a coupling part  8  for coupling the flat terminal pieces  3  and  4  of each fuse element  7  so that the fuse elements  7  are aligned along the coupling part  8 .  
     [0038] The flat terminal pieces  3  and  4 , the fusible part  5 , and the coupling part  8  are one-piece formed from a metal sheet by pressing process, as shown in FIG. 2.  
     [0039] The coupling part  8  takes the form of a strip extending in a direction in which the fuse elements  7  are arranged (horizontal direction in FIG. 1). The tips of the flat terminal pieces  3  and  4  of the fuse elements  7  are successively arrayed along one side line of the coupling part  8 .  
     [0040] During the pressing process, the cross sectional area or the like of the fusible part  5  are adjusted in accordance with a required fuse capacity for fusing.  
     [0041] The insulating housing  11  is made of insulating synthetic resin, and holds the fuse elements  7  while covering the upper half of each fuse element. The insulating housing protects at least the fusible part  5  of each fuse. Further, the insulating housing maintains a predetermined positional relation between the flat terminal pieces  3  and  4 , and prevents the fusible part  5  from being broken by external forces applied to the flat terminal pieces  3  and  4 .  
     [0042] The fuse elements  7  installed with the insulating housings  11  in the fuse belt  1  become individual blade type fuses  21  as shown in FIGS. 4A and 4B when fuse belt is cut along the boundary parts  9  between the tips of the flat terminal pieces  3  and  4  and the coupling part  8 .  
     [0043] In the fuse belt  1  of the first embodiment, the fuse elements  7  having the equal capacities are interconnected to one other so as to be aligned along the fuse belt  1 , and those aligned fuse elements  7  are oriented in the same direction.  
     [0044] The insulating housings  11  are attached to the fuse elements  7  of the fuse belt  1 , respectively, and individual blade type fuses  21  are obtained by merely cutting the boundary parts  9 .  
     [0045] A method of assembling fuses  21  to the fuse mounting parts  72  of the electric junction box  71  by using the fuse belt  1  will be described.  
     [0046] Firstly, as shown in FIG. 2, a plurality of fuse elements  7  each having a pair of parallel flat terminal pieces  3  and  4  interconnected by a fusible part  5 , and a coupling part  8  for coupling the flat terminal pieces  3  and  4  of the fuse elements  7  so as to be aligned along the fuse belt  1  are one-piece formed from a metal plate by pressing process.  
     [0047] Secondly, as shown in FIG. 3, the insulating housing  11  covering the fusible part  5  of the fuse element  7  is attached to the fuse element  7  from above, whereby a fuse belt  1  is formed as shown in FIG. 1. After the fuse elements  7  are mounted, terminal insertion holes of the insulating housing  11  are closed in a manner that a flap  11   a  integrally formed with the lower end of the insulating housing through a thin hinge is fastened to protrusions  3   a  and  4   a  of the flat terminal pieces  3  and  4 .  
     [0048] As shown in FIG. 5, when fuses  21  are assembled into fuse mounting parts  72  of the electric junction box  71  by using an automatic assembling machine or the like, fuses are supplied to a predetermined fuse supplying position. In this case, the fuses take the form of a fuse belt  1  formed with fuse elements  7  having equal capacities being coupled along the fuse belt.  
     [0049] The fuse belt  1  supplied to the fuse supplying position is separate into fuses  21 , while being cut at the boundary parts  9  each between the flat terminal pieces  3  and  4  of the fuse element  7  located at the tips of the fuse element  7  and the coupling part  8 , and those separated fuses  21  are picked up by an assembling robot (not shown) or the like, and mounted to the fuse mounting parts  72  of the electric junction box  71 .  
     [0050] The fuse belt  1  supplied to the fuse supplying position is such that the fuse elements  7  having the equal capacities are interconnected to one another so as to be aligned along the fuse belt  1 . And, those fuses  21  are separated from the fuse belt  1  just before those fuses are mounted to the fuse mounting parts  72  of the electric junction box  71 .  
     [0051] Therefore, it never happens that the fuses are supplied to the fuse supplying position in a state that those fuses include a fuse or fuses  21  being different in capacity from that of the former. Accordingly, it is surely prevented that the fuse  21  having the wrong capacity is mistakenly assembled into the electric junction box  71 .  
     [0052] Accordingly, inspection and fuse replacement, which are performed after the fuse assembling work in order to cope with the mistaken assembling of the fuses  21  into the electric junction box  71 , may be omitted. Accordingly, the automatic fuse assembling work to the electric junction box is more effectively performed.  
     [0053] The fuses  21  are supplied to the automatic assembling machine for assembling the fuses  21  to the fuse mounting parts  72  of the electric junction box  71  in a state that those fuses  21  take the form of a fuse belt  1  and are uniformly oriented.  
     [0054] In the automatic assembling machine as described above, there is no need of using an expensive part feeder as shown in FIG. 9 to regulating the attitudes of a number of blade type fuses  74  that are fed in different directions. Accordingly, the cost to automatizing the fuse assembling work is reduced.  
     [0055] In the embodiment, the fuse belt  1  as formed in advance is rolled as shown in FIG. 5, and in this state, is supplied to a given fuse supplying position. The rolled fuse belt  1  is gradually pulled out with its leading end pulled out first. In this way, the automatic assembling line is arranged compact.  
     [0056] A process ranging from a step of pressing a plurality of fuse elements  7  from a metal plate to a step of assembling the fuses  21  into the electric junction box  71  may be carried out in an in-line manner.  
     [0057] The fuses may be assembled in the following manner. The flat terminal pieces  3  and  4  of the fuse elements  7  in the fuse belt  1  are successively separated from the coupling part  8  by cutting. Then, the fuses  21  are subjected to a conduction inspection, and only qualified fuses  21  are mounted to the fuse mounting parts  72  of the electric junction box  71 .  
     [0058] In this case, immediately before the fuses  21  are mounted to the fuse mounting parts  72  of the electric junction box  71 , the fuses  21  may be inspected in conductivity.  
     [0059] Therefore, it is prevented that defective fuses are mounted to the fuse mounting parts  72 .  
     [0060] Manual work of removing a defect fuse from the fuse mounting part  72 , and mounting another fuse thereto instead of the defective one as in the case where fuses are inspected in conductivity in a post-process, is eliminated and resultantly, the productivity is improved.  
     [0061]FIG. 6 is a partial cross sectional view showing a fuse belt which is a second embodiment of the invention. FIG. 7 is a partial cross sectional view for explaining a process of manufacturing the fuse belt shown in FIG. 6. FIG. 8A is a perspective view of a whole fuse separated from the fuse belt shown in FIG. 6 and FIG. 8B is a partial cross sectional view showing the same.  
     [0062] A fuse belt  31  according to the second embodiment, as shown in FIG. 6, is made up of a plurality of fuse elements  7  each having a pair of parallel flat terminal pieces  33  and  34  interconnected by a fusible part  35 , an insulating housing  41 , shaped like T, which covers the inner side edges and the upper edges of the flat terminal pieces  33  and  34  of each fuse element  37 , and a coupling part  38  for coupling the flat terminal pieces  33  and  34  of each fuse element  37  so as to be aligned along the belt  31 . Thus, the fuse belt  31  is of the called low-height type.  
     [0063] A basic construction of the fuse belt  31  of the second embodiment is substantially equal to that of the fuse belt  1  of the first embodiment already described. A plurality of fuse elements  37  each having a pair of flat terminal pieces  33  and  34  interconnected by a fusible part  35 , and a coupling part  38  for interconnecting the fuse elements  37  so as to be aligned along the fuse belt  31  are one-piece formed from a metal plate by pressing process.  
     [0064] The coupling part  38  takes the form of a strip extending in a direction in which the fuse elements  37  are arranged (horizontal direction in FIG. 6). The tips of the flat terminal pieces  33  and  34  of the fuse elements  37  are successively arranged along one side line of the coupling part  38 .  
     [0065] During the pressing process, the cross sectional area and the like of the fusible part  35  are adjusted in accordance with a fuse capacity of the fuse for its fusing.  
     [0066] The insulating housing  41  is made of insulating synthetic resin, and protects at least the fusible part fusible part  35  of each fuse elements  37 . Further, the insulating housing maintains a predetermined positional relation between the flat terminal pieces  33  and  34 , and prevents the fusible part  35  from being broken by external forces applied to the flat terminal pieces  33  and  34 .  
     [0067] Insulation walls  41   b  provided in the insulating housing  41  function to increase a creepage distance for insulation between the parallel flat terminal pieces  33  and  34  to thereby increase the insulation performance, and further function to secure a holding strength of the fuse element  37 . Further, the Insulation walls  41   b  function to prevent that the fusible part fusible part  35  fused by overcurrent scatters to within the insulating housing  41  to possibly cause secondary shortcircuiting.  
     [0068] The fuse elements  37  installed with the insulating housings  41  in the fuse belt  31  become individual blade type fuses  51  as shown in FIGS. 8A and 8B when fuse belt is cut along the boundary parts  39  between the tips of the flat terminal pieces  33  and  34  and the coupling part  38 .  
     [0069] In the fuse belt  31  of the second embodiment, the fuse elements  37  having the equal capacities are interconnected to one other along the fuse belt  31 , and those aligned fuse elements  37  are oriented in the same direction.  
     [0070] The insulating housings  41  are attached to the fuse elements  37  of the fuse belt  31 , respectively, and individual blade type fuses  51  are obtained by merely cutting the boundary parts  39 .  
     [0071] A method of mounting fuses  51  to the fuse mounting parts  72  of the electric junction box  71  by using the fuse belt  31  will be described.  
     [0072] Firstly, as shown in FIG. 7, a plurality of fuse elements  37  each having a pair of parallel flat terminal pieces  33  and  34  interconnected by a fusible part  35 , and a coupling part  38  for coupling the flat terminal pieces  33  and  34  of the fuse elements  37  so as to be aligned along the fuse belt  31  are one-piece formed from a metal plate by pressing process.  
     [0073] Secondly, the insulating housing  41  covering the fusible part  35  of the fuse element  37  is attached to the fuse element  37  from above, whereby a fuse belt  31  is formed as shown in FIG. 6. After the fuse elements  37  are mounted, terminal insertion holes of the insulating housing  41  are closed in a manner that a flap  41   a  integrally formed with the lower end of the insulating housing through a thin hinge is fastened to protrusions  34   a  and  44   a  of the flat terminal pieces  43  and  44 .  
     [0074] When the fuses  51  are assembled into fuse mounting parts  72  of the electric junction box  71  by using an automatic assembling machine or the like, fuses are supplied to a predetermined fuse supplying position. In this case, the fuses take the form of a fuse belt  31  formed with fuse elements  37  having equal capacities being coupled along the fuse belt  31 .  
     [0075] The fuse belt  31  supplied to the fuse supplying position is separate into fuses  51 , while being cut at the boundary parts  39  each between the flat terminal pieces  33  and  34  of the fuse element  37  located at the tips of the fuse element and the coupling part  38 , and those separated fuses  51  are picked up by an assembling robot (not shown) or the like, and mounted to the fuse mounting parts  72  of the electric junction box  71 .  
     [0076] The fuse belt  31  supplied to the fuse supplying position is such that the fuse elements  37  having the equal capacities are interconnected to one another so as to be aligned along the fuse belt  31 . And, those fuses  51  are separated from the fuse belt  31  just before those fuses are mounted to the fuse mounting parts  72  of the electric junction box  71 .  
     [0077] Therefore, it never happens that the fuses are supplied to the fuse supplying position in a state that those fuses include a fuse or fuses  51  being different in capacity from that of the former. Accordingly, it is surely prevented that the fuse  51  having the wrong capacity is mistakenly assembled into the electric junction box  71 .  
     [0078] Accordingly, inspection and fuse replacement, which are performed after the fuse assembling work in order to cope with the mistaken assembling of the fuses  51  into the electric junction box  71 , may be omitted. Accordingly, the automatic fuse assembling work into the electric junction box is more effectively performed.  
     [0079] The fuses  21  are supplied to the automatic assembling machine for assembling the fuses  51  to the fuse mounting parts  72  of the electric junction box  71  in a state that those fuses  51  take the form of a fuse belt  31  and are uniformly oriented.  
     [0080] In the automatic assembling machine as described above, there is no need of using an expensive part feeder to regulating the attitudes of a number of blade type fuses  74  that are fed in different directions. Accordingly, the cost to automatizing the fuse assembling work is reduced.  
     [0081] In the fuse belt of the low height type, such as the fuses  51 , the inner edges and the upper edge of the flat terminal pieces  33  and  34 , together with the fusible part fusible part  35 , are covered with the insulating housing  41 , as shown in FIGS. 8A and 8B. Therefore, tab terminal parts greatly protruded outward from the insulating housing  41 , such as both the flat terminal pieces  75   a  and  75   b  in the conventional fuse  74  shown in FIG. 9, are not present. Accordingly, the fuse belt is rectangular in shape when viewed from front.  
     [0082] In the case of a part feeder in which the tab terminals of the fuse are supported and guided by the groove  78  and only the fuses having a regular attitude are selected and transported downstream, as in the selective transportation part  77  shown in FIG. 9, it is very difficult to select and transport the fuse belt of the low height type. For this reason, an efficiency of feeding fuses to the fuse supplying position is not good.  
     [0083] The fuse belt  31  of the instant embodiment completely solves such a problem.  
     [0084] In a fuse belt and a fuse assembling method of the invention, the fuse element, the insulating housing, the boundary part and the like are not limited to those discussed in the embodiments mentioned above, but those may variously be changed, modified and altered, and changed within the scope of the invention.  
     [0085] While in the fuse belt  1  ( 31 ) of each embodiment mentioned above, the fuse elements  7  ( 37 ) are formed on and along one side edge of the coupling part  8  ( 38 ), those fuse elements may be formed on and along both side edges of the coupling part.  
     [0086] As seen from the foregoing description, according to a fuse belt and a fuse assembling method of the present invention, when fuses are automatically assembled into fuse mounting parts of an electric junction box by using an automatic assembling machine or the like, fuses are supplied to a predetermined fuse supplying position, in the form of a fuse belt formed with fuse elements having equal capacities being coupled so as to be aligned along the fuse belt, and fuses are mounted to the fuse mounting parts of the electric junction box, while being successively separated from the fuse belt by cutting.  
     [0087] Therefore, there is no chance that the fuses are supplied to the automatic assembling machine or the like, while containing a fuse having a capacity which is different from that of the former. Accordingly, the fuse having the wrong capacity is surely prevented from being mistakenly assembled into the electric junction box.  
     [0088] Fuses are supplied, in the form of a fuse belt, to the automatic assembling machine or the like for assembling fuses into the fuse mounting part of the electric junction box. Since the fuses are uniformly oriented, there is no need of uniformly arranging fuses in their orientation by using an expensive part feeder.  
     [0089] Accordingly, the present invention succeeds in providing a fuse belt and a fuse assembling method which can surely prevent the fuse having the wrong capacity from being mistakenly assembled into the electric junction box, and can automatically assemble fuses without using the part feeder.