Patent Publication Number: US-2022216625-A1

Title: Junction Box

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to a junction box, in particular to a junction box that has a simplified and rigid structure and is easy to assemble. 
     BACKGROUND OF THE INVENTION 
     Junction box, also known as terminal box, is a connector device used to electrically connect one lead with one or more other leads, or with one or more electrical connector terminals. 
     The basic structure of the junction box includes a housing, a lead insertion hole or insertion opening, at least one conductive bar, and at least one spring clamp for pressing an inserted lead against the conductive bar. The connection between the lead and other leads or connector terminals is accomplished by the conductive bar. The junction box also provides a guide plate at a downstream position relative to the lead insertion hole or insertion opening, to guide the lead, especially the bare conductor at the front end of the lead. In application, several junction boxes are tightly arranged side by side, therefore necessary insulating elements must be provided between two of them, to avoid contact between the conductive elements of two adjacent junction boxes, which forms a short circuit. 
     US Patent Publication US2014/0287630 discloses a “Connecting terminal with a web-shaped conductor guide.” The connecting terminal is in the form of a junction box, and a guide plate extending in the direction of the box body is arranged at the lead insertion opening. On the one hand, it is used to guide the insertion of the lead and on the other hand to isolate the exposed part of the lead end. A conductive bar forms a U-shape that opens upward. The two side arms of the conductive bar are respectively used for electrical connection with a lead inserted into the box through the insertion opening. The end of the guide plate away from the insertion opening forms a free end. A gap is formed between the free end and the bottom plate of the box body. A gap is also formed between one side of the guide plate and the side wall of the box body. One side arm of the conductive bar and a portion adjacent to the side arm are respectively inserted into the side gap and the free end gap, whereby the conductive bar is affixed in the junction box. A portion of the width of the conductive bar that exposes from the gaps surrounds the space covered by the guide plate and provides a surface for electrical contact with the inserted lead. A spring clamp in the box body, at a side of the guide plate, presses the lead, that is, the bare end of the lead, to the side arm to form a firm electrical contact. On the other side of the U-shape, the junction box also provides a similar structure for inserting another lead to form an electrical connection with the other side bar of the conductive bar. 
     European Patent Publication EP3320582 discloses a connection terminal, which also forms a junction box. The junction box is used to electrically connect an inserted lead with a bus bar. A guide plate is provided below the lead insertion opening, that is, downstream of the insertion direction. A gap is formed between the guide plate and a stopper. An L-shaped conductive bar is disposed in the gap. A first spring clamp presses the conductive bar to the bus bar. A second spring clamp presses the inserted lead against the conductive bar. In the prior art, the conductive bar of the junction box is embedded in a gap formed by the lead guide plate and the box wall for fixation. The guide plate configured in this way can be integrally formed with the junction box body, and at the same time provides the functions of guiding, insulating and fixation. However, because this guide plate extends from the lead insertion opening, and its extended end provides a free end for the conductive bar to engage, the free end portion is easy to withstand excessive pressure and rupture, causing the conductive bar to fall off. 
     SUMMARY OF THE INVENTION 
     The objective of the present invention is to provide a junction box with a novel structure that can overcome the shortcomings of the conventional device. 
     The junction box according to the present invention comprises: 
     a box body, with at least one lead insertion opening provided on the box body for inserting a lead; 
     a guide plate extending towards an internal of the box from a position of the box body adjacent to the lead insertion opening, to guide the lead after being inserted; 
     wherein an extended end of the guide plate forms a lateral connecting portion, which is connected to the box body, and wherein the box body provides a first positioning plate and a second positioning plate, both protruding laterally, and the guide plate, the first and second positioning plates are configured to form a first passage space between the lower end of the guide plate and the first positioning plate, and a second passage space between the second positioning plate and one side edge of the guide plate; and wherein the guide plate, the connecting portion and the second positioning plate define a lead insertion space accessible from the second passage space; wherein the first and/or second positioning plate can also be the box wall of the box body; 
     a conductive bar formed in a plate shape and having at least one bend to form a main body and at least one first conductive arm in connection with the main body with a bent section; 
     wherein a part of the main body of the conductive bar is disposed between the extended end connecting portion of the guide plate and the first positioning plate, and the first conductive arm of the conductive bar is located in the lead insertion space; 
     characterized in that the thickness of the bent section and the first conductive arm of the conductive bar is so configured that the first conductive arm can pass through the second passage space and enter the lead insertion space; and 
     that the first conductive arm of the conductive bar is configured to move from the plane where the second passage space is located into the lead insertion space, after the first conductive arm passes the second passage space. 
     The junction box may further comprise a spring clamp disposed in the lead insertion space, at an opposite side of the first conductive arm, to press the inserted lead toward the first conductive arm. 
     The junction box may further comprise a second lead insertion opening, a second guide plate, and the conductive bar may also comprise a second conductive arm located on an end the main body opposite to the first conductive arm and extending parallel to the first conductive arm. The arrangements of the second lead insertion opening, the second guide plate and the second conductive arm correspond to that of the first lead insertion opening, the first guide plate and the first conductive arm. In this embodiment, the junction box may also include a second clamp for pressing a lead inserted through the second lead insertion opening to the second conductive arm. 
     To be specific, in this embodiment the box body further provides a second set of laterally protruding first positioning plates and second positioning plates, and the second set is configured to form a first passage space between the first positioning plate and the extended end of the second guide plate, and a second passage space between the second positioning plate and one side edge of the second guide plate; and the second guide plate, the connecting portion and the second positioning plates of the second set define a second lead insertion space, whereby the second lead insertion space is accessible from the second passage space of the second set; a part of the main body of the conductive bar is disposed between the extended end connection portion of the second guide plate and the first positioning plate; the second conductive arm of the conductive bar moves from the plane of the second passage space into the second lead insertion space, after the second conductive arm passes the second passage space. 
     In a preferred embodiment of the present invention, the first conductive arm and/or the second conductive arm is preferably moved into the first and/or second lead insertion space by an elastic force, after it pass through the second passage space. In such embodiments, one or more slight bend may be formed on the main body of the conductive bar. For example, a bend that protrudes opposite to the extending direction of the first conductive arm and/or the second conductive arm may be formed. When assembling the conductive bar, flatten the main body with hands or a jig and insert the conductive bar into the first and second passage spaces. After passing through, release the external force to restore the conductive bar to its original shape. The first conductive arm and/or the second conductive arm will move to the lead insertion space due to elastic forces. 
     Alternatively or additionally, the first conductive arm and/or the second conductive arm of the conductive bars may be further bent in the direction of the main body, so that the bent section forms an angle slightly less than  90  degrees. When assembling, the main body is flattened with hands or a jig and then inserted into the first and second passage spaces. After passing, the external force is released to restore the conductive bar to its original shape. The first conductive arm and/or the second conductive arm moves into the lead insertion space due to elastic forces. 
     In addition, the free ends of the first conductive arm and/or the second conductive arm of the conductive bar can also be arranged to bend in the direction of the main body first, and then bend in the direction opposite to the main body, forming two bends. This design helps to make the end section of the free end face straight, to form a larger area of contact with the inserted lead. 
     In the above various embodiments, the free end of the first conductive arm and/or the second conductive arm of the conductive bar may be formed, for example, with an inscribed circular arc surface, so as to be compatible with a generally cylindrical shape of the inserted lead, to form a better contact. 
     After the assembly is completed, the conductive bar will be located in the lead insertion space between the guide plate and the box body. It is usually not located in the gap between the side edge of the guide plate and the positioning plates on both sides. In a preferred embodiment of the present invention, a positioning block may be provided at the connecting portion between the lower end of the guide plate and the box body. At the same time, a positioning notch can also be provided at the corresponding position of the main body of the conductive bar. When assembling, after the conductive bar passes through the first and second passage space, the positioning block can be embedded in the positioning notch to achieve a stable positioning. 
     Alternatively or additionally, a positioning notch may be provided in the connecting portion, and a positioning block is formed at a corresponding position of the main body of the conductive bar. The assembly may be accomplished in the same way. 
     In some preferred embodiments of the present invention, a convex stopper is formed on the main body of the conductive bar, at a position corresponding to an inner edge of the guide plate after assembly, to stuck the conductive bar, after the conductive bar passes through the second passage space. In this way, the positioning notch can be omitted. 
     These and other objectives and advantages of the present invention can be more clearly appreciated from the following description of the preferred embodiments of the present invention and with reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a right-side perspective view of an embodiment of the junction box of the present invention. 
         FIG. 2  shows another perspective view of the junction box of the embodiment of  FIG. 1 ; 
         FIG. 3  shows a perspective view of one example of a connecting portion useful in the junction box of the present invention. 
         FIG. 4  shows a relative position of a conductive arm and a lead guide plate, after the conductive arm enters the inside of the lead insertion space. 
         FIG. 5  is a top view of the structure of  FIG. 4 . 
         FIG. 6  shows one example of the shape of one conductive arm useful in the junction box of the present invention. 
         FIG. 7  shows another embodiment of the end section of a conductive arm of a conductive plate suitable for the invented junction box. 
         FIG. 8  shows another embodiment of the combination of a conductive plate and a lead guide plate suitable for the junction box of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Several embodiments of the junction box of the present invention will be described below with reference to the drawings. The purpose of the embodiments is to enable readers to understand the basic principles, important and general features of the present invention, and not to limit the scope of the present invention. 
       FIG. 1  shows a right-side perspective view of an embodiment of the junction box of the present invention, and  FIG. 2  shows another perspective view of the embodiment of  FIG. 1 . As shown in the figure, the junction box  100  of the present invention has a box body  10 . The box body  10  usually has a complete box wall on the side away from the reader to provide insulation and protection. The box body  10  can generally be exposed to the reader, with only the least necessary shielding. This design can reduce the thickness of the box, while it is also feasible to provide a complete box wall, or a cover, on the near side. 
     The junction box  100  is structurally divided into two symmetrical sides by a longitudinal centerline. A lead insertion opening  11 ,  11 ′ is provided on both sides for external leads (not shown) to be inserted. The leads that can be used in the present invention are not particularly limited, and can be various coated or uncoated leads, cables, and the like. The ends of the leads are usually bare metal leads to provide electrical conductions. If the lead insertion direction is inward, a conductive bar  20  is provided inside the lead insertion opening  11 ,  11 ′. The conductive bar  20  is made of or contains a conductive material. Suitable conductive materials include various metals, conductive plastics or ceramics. Useful conductive materials are copper, silver, gold, iron, nickel, tin, aluminum, cadmium, etc. The most common are steel, aluminum and copper. The conductive bar  20  includes a main body  21  and a first conductive arm  22  and a second conductive arm  23  provided on both sides of the main body  21 . The first conductive arm  22  and the second conductive arm  23  extend toward the opening direction of the lead insertion openings  11 ,  11 ′. In the embodiment shown in  FIG. 1 , the lead insertion openings  11 ,  11 ′ are provided on a first side wall  101 , e.g., the upper side wall of the box body  10 , shown in the figure. In this embodiment, the first conductive arm  22  and the second conductive arm  23  both extend toward the first side wall  101 . However, the extending direction of the first conductive arm  22  and/or the second conductive arm  23  is not limited to the direction of the first side wall  101 . At least one of them can extend in other directions. Moreover, the extending directions of the first conductive arm  22  and the second conductive arm  23  do not need to be consistent with each other. 
     The guide plates  12 ,  12 ′ respectively extend from the inner side of the lead insertion openings  11 ,  11 ′ in the extending direction of the lead, that is, extend inward. The guide plates  12 ,  12 ′ preferably start to extend from a position of the box body at the lead insertion opening  11 ,  11 ′. In this embodiment, the guide plates  12 ,  12 ′ are preferably integrally formed with the box body  10 . However, it is also possible to install separate guide plates  12 ,  12 ′ on the box body  10 . The guide plates  12 ,  12 ′ respectively extend inward to a position where the main body  21  of the conductive bar  20  is to be installed. The first positioning plate  102 A is used to support the conductive bar  20 . In a preferred embodiment of the present invention, the first positioning plate  102 A is the second side wall  102  of the box body  10 , that is, the box wall on the side opposite to the first side wall  101 . However, the first positioning plate  102 A can also be an additional plate, and is preferably formed by extending the box body  10 . According to the junction box  100  of the present invention, the extended ends  12 A,  12 A′ of the guide plates  12 ,  12 ′ and the first positioning plate  102 A are kept at a predetermined distance, and first passage spaces  12 C,  12 C′ are formed between the two, to allow the main body  21  of the conductive bar  20  to pass through during assembly. To achieve this, the distance between the extended ends  12 A,  12 A′ of the guide plates  12 ,  12 ′ and the first positioning plate  102 A is preferably slightly larger than the thickness of the conductive bar  20 , or at least slightly larger than the thickness of the part of the main body  21  corresponding to the positioning space  13 ,  13 ′. 
     A plurality of positioning plates  103 A,  103 B can be additionally formed on the box body  10  to support and/or position the conductive bar  20 . The plurality of positioning plates can also be extended from the box body  10  and formed integrally, but it can also be the third side wall  103  and the fourth side wall  104 . 
     The spring clamps  30 ,  30 ′ are arranged inside the box body  10 , and are respectively located on the opposite sides of the first conductive arm  22  and the second conductive arm  23  with respect to the guide plates  12 ,  12 ′ to provide a pressing force to push the leads against the first conductive arm  22  and the second conductive arm  23 , after the leads are located inside the junction box  100 , behind the guide plates  12 ,  12 ′. 
     The junction box  100  according to the present invention further includes connecting portion  14  formed between the extended ends  12 A,  12 A′ of the guide plates  12 ,  12 ′ and the corresponding box wall  105 .  FIG. 3  shows a side view of a connecting portion  14  suitable for the junction box  100  of the present invention. The connecting portion  14  is generally formed in a plate shape. In the embodiment shown in  FIG. 3 , the connecting portion  14  connects the extended end  12 A of the guide plate  12  and the box wall  105  of the box body  10  to support the conductive bar  20 . Specifically, after the conductive bar  20  passes through the first passage spaces  12 C,  12 C′ between the extension ends  12 A,  12 A′ of the guide plates  12 ,  12 ′ and the first positioning plate  102 A, it enters the positioning spaces  13 ,  13 ′ between the connecting portion  14  and the first positioning plate  102 A. Here, the first passage spaces  12 C,  12 C′ may also be an extension of the positioning spaces  13 ,  13 ′. 
     According to the present invention, the width of the conductive bar  20 , that is, the width in the to-and-from direction in  FIG. 1 , is configured so that, after the conductive bar  20  passes the first passage space  12 C and  12 C′ between the extended ends  12 A,  12 A′ and the first positioning plate  102 A, there will be no part located in the first passage space  12 C,  12 C′. This design is purely a manufacturing consideration. If necessary, the width of the part can also be set to include the first passage space  12 C and  12 C′ between the extended ends  12 A,  12 A′ of the guide plates  12 ,  12 ′ and the first positioning plate  102 A, and the positioning spaces  13 ,  13 ′ between the connecting portion  14  and the first positioning plate  102 A, while the width of the first conductive arm  22  and the second conductive arm  23  is preferably not greater then the width of the positioning spaces  13 ,  13 ′ between the connecting portion  14  and the first positioning plate  102 A. However, the disadvantage of this design is that the shape of the conductive bar  20  is made complicated. 
     In addition, the box body  10  also includes second positioning plates  103 A and  104 A, provided adjacent to a lateral edge of the guide plate  12 ,  12 ′, that is, the side edge extending perpendicular to the extended ends  12 A,  12 A′ of the guide plates  12 ,  12 ′, with a predetermined distance to the guide plates  12 ,  12 ′. The second positioning plates  103 A and  104 A are used to support the conductive bar  20 , in particular, the first conductive arm  22  and the second conductive arm  23  of the conductive bar  20 . In a preferred embodiment of the present invention, the second positioning plates  103 A and  104 A are the third side wall  103  and the fourth side wall  104  of the box body  10 , that is, the two side walls connecting the first side wall  101  and the second side wall  102 . However, the second positioning plates  103 A and  104 A may also be additional plates, and are preferably formed by extending the box body  10 . According to the present invention, a predetermined distance is maintained between the lateral edge of the guide plates  12 ,  12 ′ and the positioning plates  103 A,  104 A, and second passage spaces  12 B,  12 B′ are formed between the two. The first conductive arm  22  and the second conductive arm  23  of the conductive bar  20  are allowed to pass the second passage spaces  12 B,  12 B during assembly. To achieve this, the distance between the lateral edge of the guide plates  12 ,  12 ′ and the second positioning plates  103 A,  104 A is preferably slightly greater than the thickness of the first conductive arm  22  and the second conductive arm  23 . 
     According to a preferred embodiment of the present invention, the first conductive arm  22  and the second conductive arm  23  of the conductive bar  20  pass through the second passage spaces  12 B,  12 B′ during assembly, and then enter the lead insertion space  15 , respectively, i.e., the space defined by the guide plate  12 , the rear box wall  105 , the spring clamps  30 ,  30 ′ and the second positioning plates  103 A,  104 A, see  FIG. 4 . 
     In addition, the first conductive arm  22  and the second conductive arm  23  of the conductive bar  20  are configured so that the first conductive arm  22  and the second conductive arm  23  moves from the plane of the second passage spaces  12 B,  12 B′ to the inside of the lead insertion space  15 , after they enter the lead insertion space  15 .  FIGS. 4 and 5  respectively show the relative position of the first conductive arm  22  and the second conductive arm  23  after the movement in a side view and a cross-sectional top view. In this state after the movement, the free ends of the first conductive arm  22  and the second conductive arm  23 , or the part containing the free ends, will be stuck on the inner side of the guide plates  12 ,  12 ′ to achieve a stable positioning and to provide a more stable clamping effect to the inserted lead. 
     In a preferred embodiment of the present invention, the force to move the first conductive arm  22  and the second conductive arm  23  into the inside the lead insertion space  15 , after they passes through the second passage space  12 B,  12 B′, is preferably an elastic force. To achieve this, one or more slight bend may be formed on the main body  21  of the conductive bar  20 . For example, a bend that protrudes opposite to the extending direction of the first conductive arm  22  or the second conductive arm  23  may be formed. When assembling the conductive bar  20 , flatten the main body  21  with hands or a jig (not shown) and insert the conductive bar  20  into the first and second passage spaces  12 C,  12 C′. After passing through, release the external force to restore the conductive bar  20  to its original shape. The first conductive arm  22  and the second conductive arm  23  will move to the inside of the lead insertion space  15  due to elastic forces 
     Alternatively or additionally, the free ends of the first conductive arm  22  and/or the second conductive arm  23  of the conductive bar  20  may be slightly bent in the direction of the main body  21 , so that the bent section forms an angle slightly less than  180  degrees. When assembling, the conductive arms are flattened with a tool and then the conductive bar  20  is inserted into the first and second passage spaces  12 C,  12 C′. After passing, the external force is released to restore the conductive bar  20  to its original shape. The free end of the first conductive arm  22  and/or the second conductive arm  23  moves into the lead insertion space  15  due to elastic forces. Another alternative or additional arrangement is to make the conductive bar  20  so that the first conductive arm  22  and/or the second conductive arm  23  is slightly bent in the direction of the main body, as shown in  FIG. 6 . After entering the lead insertion space  15 , the part can be stuck on the rear side of the guide plate  12 ,  12 ′.  FIG. 6  shows one example of the shape of one conductive arm useful in the junction box of the present invention. 
       FIG. 7  shows another example of the end portion of the conductive bar suitable for the junction box of the present invention. The structure of  FIG. 7  can be regarded as a modification of the previous embodiment. In this embodiment, the free end of the first conductive arm  22  and/or the second conductive arm  23  of the conductive bar  20  is first bent in the direction of the main body, and then bent in the opposite direction, forming two bends. This design helps to make the end of the free end face upward to form a larger area of contact with the inserted lead. 
     The free end of the first conductive arm  22  and/or the second conductive arm  23  of the conductive bar  20  may form, for example, with an inscribed circular arc surface, so as to be compatible with a generally cylindrical shape of the inserted lead, to form a better contact. The design of the inscribed can be applied to any embodiment of the present invention. And there is no restriction on the shape of the inscribed. Depending on the manufacturing process, different inscribed shapes can be determined, as long as it can form a larger area of contact with the inserted lead. For example, two flat inner walls at any angle would provide the same function. 
     After the assembly is completed, the conductive bar  20  will be located inside the lead insertion space  15  between the guide plates  12 ,  12 ′ and the box wall  105 . It is usually not located in the first passage space  12 C,  12 C′ and/or the second passage space  12 B,  12 B′. 
     In a preferred embodiment of the present invention, the connecting portion  14  at the extended end of the guide plate  20  may be provided with a positioning block  16 , see  FIG. 3 . At the same time, a positioning notch (not shown) can also be provided at the corresponding position of the main body  21  of the conductive bar  20 . When assembling, after the conductive bar  20  passes through the first passage spaces  12 C,  12 C′ and the second passage spaces  12 B,  12 B′, the positioning block  16  can be embedded in the positioning notch to achieve a more stable positioning. 
     Alternatively or additionally, a positioning notch (not shown) may be formed in the connecting portion  14 , and a positioning block (not shown) may be formed at a corresponding position of the conductive bar main body  21 . The assembly method would be the same. 
     Alternatively or additionally, a convex stopper  21 B can be formed on the main body  21  of the conductive bar  20  at a position corresponding to an edge of the guide plates  12 ,  12 ′ after assembly, to stuck the conductive bar  20  on the inner side of the guide plates  12  and  12 ′, after passing through the second passage spaces  12 B and  12 B′, as shown in  FIG. 8 .  FIG. 8  shows the relation of a conductive bar and a lead guide plate suitable for the junction box of the present invention. In this way, the positioning notch can be omitted. 
     In the junction box  100  described above, the box body  10  on one side, the lead insertion opening  11  on the side, the conductive bar  20  extending from the lead insertion opening  11  and the first conductive arm  22  of the conductive bar  20 , as well as the connecting portion  14  supporting the conductive bar  20 , the positioning plates  102 A,  103 A, the first passage space  12 C, the second passage space  12 B, and the positioning space  13 , form a lead connection module. One, two or more lead connection modules of the present invention can be provided in a junction box to provide various functions. 
     For example, a junction box may only include one lead connection module of the present invention, which is connected to a lead connection module that is not one of this invention and is located inside or outside the junction box. A junction box including two lead connection modules of the present invention, with the conductive bar  20  used for electrical and structural connection, would be a typical application. However, three or more of the invented lead connection modules can be provided in one junction box to provide various applications. 
     The present invention has been described in relation to particular examples, which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will appreciate that many different combinations will be suitable for practicing the present invention. Various aspects and/or components of the described embodiments may be used singly or in any combination. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.