Patent Publication Number: US-2022216622-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 inserted 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 may form a short circuit. 
     US Patent Publication US2014/287630 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 and a conductive bar. The box body is provided with first and second lead insertion openings, first and second guide plates each extending from an opening, and first and second lateral connecting portions each in connection with an extending end of a corresponding guide plate and the box body. At least two sets of first and second positioning plates each forming a passage space with one guide plate in connection with a lead insertion space defined by the corresponding guide plate, the corresponding connecting portion and the corresponding positioning plate. The shape of the conductive bar is specially designed so that after two conductive arms enter the lead insertion space through the passage space, they move into an inside of the lead insertion space. 
     Specifically, the invented junction box comprises a box body, comprising a side wall and at least one box wall, wherein the side wall provides at least two lead insertion openings for a least to be inserted; and a conductive bar arranged in the box body, comprising a man body and two conductive arms, and each conductive arm points to a lead insertion opening; 
     wherein the box body further comprises: 
     at least two guide plates, each attached to the box body and extending from a lead insertion opening in a wire insertion direction; 
     a laterally connecting portion connected to an extended end of a guide plate and the side wall; 
     at least two sets of first and second positioning plates protruding laterally from the box wall, configured to respectively form a first passage space between a first positioning plate and an extended end of a corresponding guide plate, and a second passage space between a second positioning plate and one side of the corresponding guide plate; and each to define a lead insertion space by one second positioning plate, a corresponding guide plate, a connecting portion, and the box wall, the lead insertion space being accessible from the second passage space; wherein the first and/or the second positioning plate can also be a wall of the box body; and 
     wherein a part of the main body of the conductive bar is arranged between the connecting portion and the first positioning plate, and the conductive arms on both sides of the conductive bar are located inside the lead insertion space; and 
     a thickness of the conductive bar is configured so that the conductive arms on both sides can pass through the corresponding second passage space and enter the corresponding lead insertion space; 
     characterized in that an extending direction of the two conductive arms is substantially parallel, and after the conductive arms on both sides of the conductive bar enter the lead insertion space, they move from the plane of the second passage space to the inside of the lead insertion space. 
     The junction box may further comprise a spring clamp disposed in the lead insertion space, at an opposite side of the second positioning plate, to press an inserted wire toward a conductive arm. 
     The extending direction of the two conductive arms of the conductive bar can be opposite. In such embodiments, the main body of the conductive arm is substantially linear, or comprise two sections that form an angle, or two arm sections that keep a certain distance from each other. 
     The extending direction of the two conductive arms of the conductive bar can be substantially the same. In such embodiments, the conductive arm may include two arm sections forming an angle. 
     The extending direction of the two conductive arms of the conductive bar can form an angle. In such embodiments, the conductive arm may include two arm sections forming an angle. 
     In a preferred embodiment of the present invention, the conductive arms on both sides to move into the inside of the lead insertion space preferably by an elastic force. In such embodiments, one or more slight bend may be formed on the main body of the conductive bar, to provide the elastic force. In addition, the end portion of the conductive arms on both sides can also be bent toward the main body. 
     The conductive bar may further comprise a third conductive arm attached to the main body of the conductive bar. The conductive bar may further include a fourth conductive arm attached to the main body of the conductive bar. The extending directions of the third conductive arm and the fourth conductive arm can be the same or opposite to the extending direction of one of the two side arms, and can also form an angle with them. 
     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 the 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  shows one example of the shape of one conductive arm useful in the junction box of the present invention. 
         FIGS. 6A-6D  show several examples of the shape of a conductive bar suitable for the junction box of the invention. 
         FIG. 7A-7F  show several examples of the structure of a conductive bar applicable to 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  105  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 figures also show the side walls  101 - 104  protruding around the box wall  105 . In the embodiment of  FIG. 1 , the junction box  100  roughly includes four side walls. 
     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 . 
     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 in supporting 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,  104 A 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 , respectively, 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 portions  14 ,  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 portions  14 ,  14 ′ are 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 ′. 
     On both sides of the box body  10 , the guide plate  12 , the connecting portion  14 , the second positioning plate  103 A and the box wall  105  define a first lead insertion space, while the guide plate  12 ′, the connecting portion  14 ′, the second positioning plate  103 A and the box wall  105  define a second lead insertion space, respectively for electrically connecting a lead and the conductive bar  20 , after the lead is inserted, so that the two leads form an electrical connection. 
     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 configured 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 ,  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 than 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 box wall  105  and the second positioning plates  103 A,  104 A, respectively, 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 . 
       FIG. 4  show the relative position of the first conductive arm  22  and the second conductive arm  23  after the movement in a side 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 bars  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. After entering the lead insertion space  15 , the part can be stuck on the rear side of the guide plate  12 ,  12 ′. 
     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. 
     Although the conductive bar  20  shown in  FIGS. 1 and 2  has a U shape, i.e., a linear main body  21  and two conductive arms  22 ,  23  extending towards the same direction, this is only one example of the shape of the conductive bar  20 . In the preferred embodiments of the present invention, the extending direction of the two conductive arms of the conductive bar can be opposite, the same or form an angle.  FIGS. 6A-6D  show several examples of the shape of the conductive bar suitable for the junction box of the present invention.  FIG. 6A  shows a linear conductive bar  20  main body  21  with the first conductive arm  22  and the second conductive arm  23  extending in opposite directions. In this embodiment, two lead insertion openings  11 ,  11 ′ are provided on the first side wall  101  and the second side wall  102  opposite to the first side wall  101 , both of the box body  10 , respectively.  FIG. 613  shows that the main body  21  of the conductive bar  20  is in the U shape, and the two conductive arms extending directions of the first conductive arm  22  and the second conductive arm  23  are opposite. In this embodiment, two lead insertion openings  11 ,  11 ′ are provided on the first side wall  101  and the second side wall  102  of the box body  10 , respectively.  FIG. 6C  shows the main body  21  of the conductive bar  20  includes two sections, forming an angle of about 90 degrees, with one section extending towards the right in the drawing and the other towards the reader. The two conductive arms  22 ,  23  both point to the upper direction of the drawing. In this embodiment, the two lead insertion openings  11 ,  11 ′ are both provided on the first side wall  101  of the box body  10 , but the first side wall  101  includes a portion extending in the thickness direction.  FIG. 6D  shows the main body  21  of the conductive bar  20  includes two sections forming an angle of about 90 degrees, with one section extending towards the right in the drawing and the other towards the reader. The two conductive arms both point to the reverse directions, that is, upper and lower directions, both of the drawing. In this embodiment, the two lead insertion openings  11 ,  11 ′ are provided on the first side wall  101  and the second side wall  102 , respectively, of the box body  10 , but the second side wall  101  includes a portion extending in the thickness direction. 
     In addition, the conductive bar  20  may further include a third conductive arm  24  and/or a fourth conductive arm  25 . The third conductive arm  24  and/or the fourth conductive arm  25  may be provided by a second conductive bar attached to the main body of the conductive bar  20 . The extension directions of the third conductive arm and the fourth conductive arm can be the same or opposite to the extension direction of one of the two conductive arms, and can also form an angle. 
       FIG. 7  shows several examples of the structure of the conductive bar suitable for the junction box of the present invention. As shown in  FIG. 7A , the conductive bar  20  includes a third conductive arm  24  attached to the main body  21  of the conductive bar  20 , and the extension direction of the third conductive arm  24  is opposite to the first conductive arm  22  and the second conductive arm  23 .  FIG. 7B  shows that the conductive bar  20  includes a third conductive arm  24  and a fourth conductive arm  25  attached to the main body of the conductive bar  20 , and the extension direction of the latter two is opposite to the first conductive arm  22  and the second conductive arm  23 . 
     In the example shown in  FIG. 7C , the conductive bar  20  includes a third conductive arm  24  attached to the main body of the conductive bar  20 , and the extension direction of the third conductive arm  24  is the same as the first conductive arm  22  and the second conductive arm  23 .  FIG. 7D  shows that the conductive bar  20  includes a third conductive arm  24  and a fourth conductive arm  25  attached to the main body of the conductive bar  20 , and the extension direction of the two is the same as the first conductive arm  22  and the second conductive arm  23 . In the example shown in  FIG. 7E , the conductive bar  20  includes a third conductive arm  24  attached to the main body of the conductive bar  20 , and the extension direction of the third conductive arm  24  is the same as that of the first conductive arm  22  and opposite to the second conductive arm  23 .  FIG. 7F  shows that the conductive bar  20  includes a third conductive arm  24  and a fourth conductive arm  25  attached to the main body of the conductive bar  20 , and the extension direction of the two is opposite to the first conductive arm  22  and the second conductive arm  23 . 
     In the above embodiments, the number, position and arrangement of the lead insertion openings  11 ,  11 ′, guide plates  12 ,  12 ′, spring clamps  30 ,  30 ′, the first positioning plate  102 A, and the second positioning plates  103 A,  104 A may need to be modified accordingly. However, this is not any problem for those skilled in the art. Details thereof are thus omitted. 
     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.