Patent Publication Number: US-2012043106-A1

Title: Junction box with spacer

Description:
RELATED APPLICATIONS 
     This patent application claims priority from and incorporates by reference German patent application 10 2010 034631.4-55 filed on Aug. 17, 1010. 
     FIELD OF THE INVENTION 
     The invention relates to a junction box in particular for a solar module including a housing with functional components for connecting two connecting contacts at the solar module arranged therein. 
     BACKGROUND OF THE INVENTION 
     A junction box of this type is disclosed in DE 10 2007 027 861 A1. This junction box is configured by the manufacturer to be mounted on solar modules through an automated production process. The junction box housing is provided with connecting conductors for putting out electricity generated by the solar module, wherein the connecting conductors are supported by a cable support. The cable support is used furthermore for supporting the junction box cover through which the junction box can be closed after being mounted at the solar module. 
     The cable support disclosed in DE 10 2007 027 861 A1 includes a so-called receiving pin which is used as an engagement point for a gripper of an assembly robot. According to this printed document the gripper engages the junction box at its outsides and engages the cable support at its receiving pin in order to provide the so-called connection set with a glue device for attachment at the solar module. 
     It can be derived from the figures of DE 10 2007 027 861 A1 that the receiving pin is also used for arranging plural cable supports on top of one another. 
     As described in DE 10 2007 027 861 A1 junction boxes are required which are pre-configured for fully automated production of solar modules, wherein the junction boxes have to be provided as required by fully automated production. For this purpose the junction boxes are stored stacked in magazines at the assembly line for removal through a production robot. A well defined arrangement of the particular stacked junction boxes within the magazine is required since the assembly robots can only adapt their grippers within a defined space to various positions of the junction boxes. Typically the correct position is provided through respective magazine racks. Alternatively it is conceivable that the junction boxes are applied to particular carrier materials in defined distances. Carrier materials of this type are then provided in a timed manner to the production robot according to the spacing of the junction boxes from one another. 
     In particular the prior art magazine racks for storing preconfigured junction boxes in a defined position have had a fair amount of problems. Typically the racks have a considerable height; however, they are comparatively narrow due to the dimensions of the junction boxes, so that the gripper device for retrieving the junction boxes has to move into a comparatively narrow and high channel, which places particular demands upon the control system. At the same time the magazine rack must be precisely positioned in order to prevent a collision with the gripper device while retrieving junction boxes. 
     BRIEF SUMMARY OF THE INVENTION 
     Thus, it is an object of the invention to provide a new junction box which can be advantageously stored at assembly lines for solar modules. 
     The object is achieved by a junction box with a housing with functional components arranged therein for connecting with solar module connecting contacts, wherein the housing supports a spacer configured to fixate another junction box at a distance from the junction box supporting the spacer, in particular with the characterizing features, according to which the housing of the junction box includes a spacer through which another junction box can be arranged and fixated in position with respect to the junction box bearing the spacer. 
     By using at least one spacer preferably, however, three spacers the junction box according to the invention facilitates arranging junction boxes on top of one another thus forming storage stacks. The spacers are furthermore used for arranging the junction boxes at one another with positional fixation. Consequently a rack which prevents a movement of junction boxes relative to one another is not required anymore. The junction box stack is stable by itself. 
     In an advantageous embodiment it is provided that the junction box includes three spacers which form the corners of a triangle. 
     The arrangement of the spacers as corners of a triangle provides a very stable arrangement of the junction boxes on top of one another. 
     For producing and using the ensuing solar module it is advantageous that the spacer is supported in a disengageable manner in one of the supports of the junction box. 
     This embodiment facilitates removing the spacer before or after mounting the junction box at the solar module. Since the spacers are longer than the height of the junction box in order to provide a spacing of the junction boxes from one another, the entire height or transport height of the solar module can be reduced by removing the spacers. 
     It is advantageous when the spacer is arranged in the support through friction locking. 
     However, it is also conceivable that the spacers are connected at the junction box through zones with weakened material and removing the spacer from the junction box is provided through a separation along the zone with weakened material through a tool or through overload. However, supporting the spacer through friction locking is advantageous since a spacer of this type can be removed in a simple manner, for example, through moving it out of the support. 
     It is furthermore provided that the support of the junction box or the base of the spacer is provided with ribs which provide friction locking engagement between the support and the spacer. Through selecting the number of ribs the frictional force required for the support can be influenced easily. 
     For arranging plural junction boxes on top of one another through coupling the spacers of different junction boxes amongst one another it is provided that a head of an additional spacer is supported through friction locking in the receiver of the base. 
     Also for this coupling it is advantageous that the head or the receiver is provided with ribs for generating the friction locking engagement. 
     An exemplary embodiment is characterized in that the number of ribs for receiving the spacer or the head of the spacer is lower than the number of ribs of the spacer or the junction box or the base of the spacer. 
     The lower number of ribs between the receiver and the head compared to the number of ribs of support and base provides that the friction forces between the support and the base are greater than the friction forces between the receiver and the head of two spacers. 
     Considering that the junction boxes are arranged in a stack in which the head of the spacer of the first junction box is received in a receiver of the spacer of the second junction box, it is provided through frictional engagement with different strength that only the head and the receiver separate from one another as a matter of principle when removing a junction box from the stack, but the support and the base doe not separate from one another. Thus, each spacer remains arranged at the associated junction box when the junction box is retrieved and each spacer is removed at the earliest after retrieval and before mounting the associated junction box at the solar module. The spacers themselves can be collected and recycled. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is subsequently described based on an embodiment with reference to drawings wherein: 
         FIG. 1  illustrates a junction box according to the invention in a top view; 
         FIG. 2  illustrates the junction box according to  FIG. 1  in a perspective view; 
         FIG. 3  illustrates two junction boxes placed behind one another according to  FIG. 1  in a perspective view; 
         FIG. 4  illustrates a partial sectional view of two junction boxes arranged on top of one another according to the section line IV-IV in  FIG. 1 ; 
         FIG. 5  illustrates a spacer according to the invention in a lateral view; 
         FIG. 6  illustrates a sectional view of the spacer according to the sectional line VI-VI in  FIG. 5 ; 
         FIG. 7  illustrates a perspective view of the spacer according to  FIG. 5 ; 
         FIG. 8  illustrates a partial view of the junction box according to  FIG. 1  illustrating a support device for a spacer; 
         FIG. 9  illustrates a partial view of the junction box according to  FIG. 1  with a view of a support device according to  FIG. 8  with an inserted spacer; 
         FIG. 10  illustrates a horizontal sectional view through the support device of the junction box according to  FIG. 9  provided with the spacer; 
         FIG. 11  illustrates a horizontal sectional view of the base of the spacer with an inserted head of another spacer. 
         FIG. 12  illustrates a perspective view of a junction box schematically illustrating two centering bosses; 
         FIG. 13  illustrates a schematic view of a centering boss in a perspective view; and 
         FIG. 14  illustrates a vertical sectional view through the junction box according to  FIG. 12  with centering bosses inserted. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A junction box according to the invention for solar modules is designated overall with the numeral  10  in the drawings. 
     The junction box  10  includes a housing  11  which forms an inner cavity  12 . Connection contacts  13  are arranged in the cavity  12  which are provided for connecting with contacts of the solar module which are not illustrated. The connection contacts  13  are electrically connected through functional components embedded in the housing material, like, for example, bypass diodes, with connecting conductors  14  leaving the housing  11 , wherein ends of the connecting conductors are provided with plug-in connectors  15 . 
     The interruption of the connecting conductors  14  illustrated herein between their exit from the junction box  10  and the end provided with plug connectors  15  is due to the illustration. In reality these are two respective connecting conductors  14  extending from the housing  11  to the plug connector  15 . 
     The housing  11  of the junction box  10  forms mechanisms  16  on both sides of the inner cavity  12  which are plug-in complementary to the plug connectors  15 , wherein the mechanisms  16  are used for supporting the plug connectors  15  at the junction box  10  for transportation and assembly. Thus, the mechanisms  16  are used for cable support. 
     Additionally the housing  11  of the junction box  10  forms supports  17  which are used for receiving spacers  18 , c.f. e.g.  FIG. 5 . The support  17  is configured as a hollow cylinder, in particular as a circular hollow cylinder as apparent, for example, from  FIG. 2 . 
       FIG. 3  illustrates an arrangement of two junction boxes  10  on top of one another. Thus, the spacers  18  are inserted into the supports  17  for each junction box  10 . In the actual embodiment each junction box  10  forms three supports  17  respectively receiving one spacer  18 . 
     The spacer  18  is illustrated in detail in  FIGS. 5 through 7 . It has a substantially cylindrical body which is overall designated with the numeral  19 . 
     The circular cylindrical body  19  has slight conicity so that it also can be designated as a frustum. The element  19  has three portions. The lower portion is formed by the so-called base  20 . The head  21  of the element  19  is arranged at the opposite end. A spacer  22  is configured between the base  20  and the head  21  which are configured at opposite ends of the element  19 . 
     The base  20  includes approximately the portion of the element  19  which is arranged in the support  17  of a junction box  10 . The base includes a base disc  23  forming the base of the element  19 , wherein the base disc has a larger diameter than the element  19  and transitions into the element  19  through a shoulder  24  configured as a recess. The portion of the cylindrical element  19  joining the base disc  23  in as far as it is associated with the base  20  is provided with ribs  25  offset from one another in circumferential direction and parallel to the longitudinal axis of the spacer  18 . 
     The transition from the spacer  22  of the element  19  to the head  21  is formed by a shoulder  26 . The shoulder  26  is formed in that the head  21  of the spacer  18  is reduced with respect to its diameter relative to the spacer  22 . 
     The head  21  is also provided with ribs  25 . Also the ribs are offset from one another in circumferential direction and oriented parallel to the longitudinal axis of the spacer  18 . Compared to the number of ribs  25  which support the base  20  the number of ribs  25  which support the head  21  is lower. The head  21  furthermore includes a support section  27  arranged at an upper end of the spacer  18 , wherein the support section is provided with a conical circumferential surface  28 . 
       FIG. 6  illustrates a longitudinal sectional view through the spacer  18  according to the sectional line VI-VI in  FIG. 5 . As apparent in  FIG. 6  the spacer  18  is hollow inside and initially includes a receiver  30  that is introduced into the base  20  and that is open towards the base of the spacer. Between the receiver  30  and the head  21  stabilization walls  29  are integrally molded in the interior of the spacer  18  at the inner circumferential surface  31 . The wall surfaces  32  of the stabilization walls parallel to the base disc  23  define the receiver  30  towards the head  21  of the spacer  18 . 
     The receiver  30  is used for inserting the head  21  of another spacer  18 . Therefore the receiver is configured complementary to receive the head  21  of another spacer  18 . The walls surfaces  32  form a stop for the insertion movement of the head  21  of another spacer  18 . The conical circumferential surfaces  28  of the head  21  are used for facilitating an insertion into a receiver  30 . 
     As evident eventually also from  FIG. 6  the head  21  of the spacer  18  is provided with a longitudinal bore hole  33  which reaches into an interior of the spacer  18 . The bore hole  33  in the head  21  of the spacer  18  facilitates pressure compensation when a head  21  of another spacer  18  penetrates the receiver  30 . The air displaced by the volume reduction of the cavity of the spacer  18  can escape through the bore hole  33 . 
       FIG. 7  illustrates the spacer  18  again in a perspective view. It is evident in particular that a groove is respectively fabricated in the stop surface  34  of the base disc  23  and of the shoulder  26 . The groove  35  of the base disc  23  is approximately star-shaped, the groove of the shoulder  26  is approximately square. The grooves  35  and  36  are used for receiving material chips possibly coming off the ribs  25  when inserting the spacer  18  into a support  17  at the junction box or when inserting the head  21  into a receiver  30  of the spacer  18  which will be described in more detail infra. 
       FIG. 8  illustrates the junction box  10  in a partial view. This is an enlarged detailed view of the support  17  of the junction box  10  from below. 
     The support  17  is substantially configured as a hollow cylinder and configured substantially with a complementary shape to the base  20  of the spacer  18 . Thus, the support  17  initially includes a bore hole  37  with a larger diameter, wherein the bore hole receives the base disc of the base  20  when the spacer  18  is inserted. The stop surface  34  contacts the ring surface  38  of the support  17  when the spacer  18  is inserted. Thus, the annular surface  38  is used for defining the insertion depth of the spacer  18  into the support  17 . 
     A hollow cylindrical section  39  with smaller diameter of the support  17  connects to the bore hole  37  with a comparatively larger diameter, wherein the cavity  40  of the hollow cylindrical section with smaller diameter is configured with a complementary conical shape according to the conicity of the spacer  18 . However, it is essential that the inner surface of the hollow cylindrical section  39  of the support  17  is substantially planar and in particular does not include recesses that are complementary for receiving the ribs  25 . The cavity  40  of the support  17  thus is only shape complementary to the base  20  of the spacer  18  in that it forms a base without ribs while only maintaining a particular clearance fit  42 . 
       FIG. 9  substantially corresponds to the view of  FIG. 8  besides the fact that a spacer  18  is now inserted into the support  17 . As illustrated in this view the base disc  23  is completely received in the larger diameter bore hole  37  of the support  17 . 
     The spacer  18  is fixated through friction locking in the support  17 , wherein the friction locking is provided through the ribs  25  of the base  20 . Since the ribs expand the outer circumference of the base  20 , the receiver  17 , however, does not provide any supplemental space for the ribs  25 , a press fit is provided through inserting the spacers  18  and the friction locking engagement provided by the ribs  25 . 
     When inserting the spacer  18  into the support  17  it can be provided that the ribs  25  do not plastically deform in the intended manner but that materials are removed in chips. In order to still provide a precisely fitted reception of the base disc  23  in the larger diameter bore hole  37 , thus a substantially full surface contact of the contact surface  34  of the base disc  23  at the annular surface  38 , the star-shaped grooves  35  illustrated in  FIG. 7  are provided. When material is removed in chips the chips are received by the groove instead of moving between the stop surface  34  and the ring surface  38 . 
       FIG. 10  illustrates a sectional view through the support  17  according to the sectional line X-X in  FIG. 9  horizontally through the base  20  of the spacer  18 . Reference is made initially to the clearance fit  42  between the base  20  and the inner surface  41  of the support  17 . Also the ribs  25  are clearly visible which are arranged at the outer surface of the base  20  with a circumferential offset. The ribs  25  are overemphasized in  FIG. 10 . It appears that the ribs  25  significantly engage the inner surface  41  of the support  17 . 
     It cannot be excluded that besides a plastic deformation of the ribs  25  also a deformation is provided at the inner surface  41  of the support  17  through inserting the spacer  18 . However, it is appreciated that primarily the ribs  25  will deform. The overemphasis of the ribs  25  is only used for a better illustration of the ribs in  FIG. 10 . 
       FIG. 11  also illustrates a horizontal sectional view of the support  17  of the junction box  10 . The sectional plane is in the contact portion of the annular surface  38  and the stop surface  34  of the base disc  23 . In this figure it is illustrated how a head  21  of another spacer  18  is arranged in the receiver  30  of the base  20  of a first spacer  18 . Also here there is a clearance fit  42  between the outer circumferential surface of the head  21  that has no ribs and the receiver  30 . Only the ribs  25  establish a friction locked contact between the inner surface  43  of the receiver  30  and the head  21 . Consequently the head  21  is supported in a friction locked manner through a press fit in the receiver  30 . Also here the ribs are overemphasized for illustration purposes like in  FIG. 10 . The recited square groove  36  is also used here for receiving possibly occurring chips when inserting the head  21  into the receiver  30 . 
     It is apparent in  FIG. 11  that the number of ribs  25  at a head  21  is smaller than the number of ribs  25  at a base  20 . In the embodiment of  FIG. 11  a ratio of approximately 2:1 was selected. When the materials of the spacer element  18  and of the support  17  are the same and the ribs  25  are sized identically at a head  21  with the ribs  25  at a base  20  a ratio of approximately 2:1 will also be achieved between the forces which occur when disengaging the closing connector between the support  17  and the base  20  or between the receiver  30  and the head  21 . 
     When junction boxes  10  are arranged on top of one another using the spacers  18  as illustrated in  FIGS. 3 and 4  it can be achieved through the ratios of frictional forces recited supra and only defined by the ribs  25  that only the connection between receiver  30  and head  21  disengages when the upper junction box  10  is removed from the stack of junction boxes. This assures that the spacers  18  of each junction box  10  remain in the respective support  17 . In another process step the spacer  18  can then be pushed out of the support  17 . The junction box can then be mounted on a solar module without the spacer  18 . 
     Furthermore  FIG. 4  clearly illustrates the stacking system of the junction boxes  10 . As evident from the vertical sectional view through the spacers  18  in  FIG. 4  a respective head  21  of a first spacer  18  engages the receiver  30  of another spacer, so that the weight of the respectively next higher junction box is reacted through the spacers  18 . 
     The junction boxes  10  are consequently arranged through arranging the spacers  18  on top of one another maintaining a distance and are arranged with stable positioning relative to one another. 
     In conclusion a new junction box  10  is illustrated including spacers for arranging plural junction boxes  10  on top of one another which satisfies the requirements of a fully automated production process of solar modules in an advantageous manner. 
     The following is disclosed in addition: 
     A) A spacer  18  for a junction box  10  for a solar module, wherein the spacer  18  is disengageably arranged at the junction box  10 . 
     B) The spacer according to A), wherein the spacer  18  forms a head  21  and a base  20  at opposite ends, wherein the base  20  includes a receiver  30  for arranging the head  21  of another spacer  18  which is configured complementary at least with respect to its head  21 . 
     C) The spacer according to B) wherein the spacer  18  includes ribs  25  at its base  20  for friction locked arrangement at the junction box  10  and additional ribs  25  at the receiver  30  of the base  20 , wherein the additional ribs are used for friction locked support of another spacer which is configured receiver complementary at least with its head  21 , or wherein the head  21  of the additional spacer  18  is provided with ribs  25  which are used for friction locked support in the receiver  30  of the base  20 . 
     The following is disclosed in addition: 
     D) An arrangement of plural junction boxes  10  according to the preamble of patent claim  1  on top of one another, wherein one spacer  18  offsets the junction boxes  10  from one another and the spacer  18  of a first junction box  10  engages a head  21  in a receiver  30  of a base  20  of the spacer  18  of a second junction box  10 . 
     E) An arrangement according to D), wherein the spacer  18  is configured according to one of the letters A-B. 
     F) An arrangement according to D), wherein the junction boxes  10  are configured according to one of the claims  1 - 9 . 
     The following is illustrated in addition: 
     G) A junction box  10  in particular for a solar module including a housing  11  whose interior  12  is configured with functional components, wherein the housing  11  includes a centering recess for an engagement of a centering boss. 
     H) The junction box according to G), wherein the centering recess is a conical recess. 
     K) The junction box according to G) wherein a wall with a slanted surface is configured within the centering recess. 
     Additionally a junction box is disclosed, in particular for a solar module, including a housing whose cavity is configured with functional components. Junction boxes of this type are known, for example, from DE 10 2007 023 210. When transitioning to fully automated production of solar modules it is required to provide junction boxes which satisfy the requirements of a fully automated production process. 
     A junction box of this type is characterized in particular in that the housing includes a centering recess for engagement of a centering boss. 
     It is an advantage of this junction box that a centering of the junction box relative to the assembly tool can be provided when receiving the junction box through the gripper of a respective assembly robot. 
     It is another advantage that an alignment of the junction box can be provided subsequent to its mounting at the solar module through engagement of a centering boss in the centering recess. 
     Thus, it is possible to perform a possibly necessary readjustment of the junction box relative to the solar module subsequent to the actual assembly process of the junction box in a second process step. 
     An exemplary embodiment that provides the centering recess is a conical recess. Alternatively it is provided that a wall is configured with a slanted surface within the centering recess. Both embodiments have the advantage that the slanted surface or the conical shape of the centering recess in combination with a respectively configured centering boss substantially simplify the alignment of the junction box relative to the solar module. 
     The disclosed junction box is described in more detail based on an exemplary embodiment with reference to drawing  FIGS. 12-14 , wherein: 
     A junction box is designated overall with the reference numeral  100  in the drawings. 
     The junction box  100  is formed by a housing  101  which encloses an inner cavity  102 . The cavity includes connecting contacts for connecting with solar module conductors which are not illustrated. The cavity  102  can be closed through encasement and/or application of a cover which is not illustrated. 
     Centering recesses  104  are formed at the housing laterally from the cavity  102 . Plural walls  105  are provided within the centering recesses, wherein the walls are oriented towards the centering boss  106  and are provided with slanted surfaces  108  descending towards the base  107  of the centering recess  104 . 
       FIG. 13  illustrates the centering boss  106  in a schematic view from below wherein the centering boss is already schematically illustrated in  FIG. 12 . 
     The centering boss  106  is provided at its end oriented towards the junction box  100  with centering surfaces  109  conically tapering towards the junction box  100 . A substantially cuboid section  110  adjacent to the centering surfaces  109  forms a contact device for the centering boss  106  and simultaneously forms a spacer for the centering surfaces  109  relative to the base  107  of the centering recess  104 . 
     In order to center the junction box  100  relative to a gripper of an assembly robot or for centering the junction box  100  relative to a solar module that is not illustrated the centering bosses  106  move into the centering recesses  104 . Thus at least one square section  110  slides along the slanted surfaces  108  of the walls  105  and thus moves the junction box  100  relative to the centering boss and consequently also relative to the solar module or relative to the gripper. Since the centering surfaces  109  of the centering boss  106  contact the slanted surfaces  108 , fine centering of the junction box  100  is provided. The cuboid sections  110  contact the base  107  of the centering recess  104  and thus form a movement stop. Thus, they protect the walls  105  against a possible deformation through further insertion of the centering bosses  106  and thus protect the junction box  100  against damages. Thus, the slanted surfaces  106  transition into wall sections  11  declining perpendicular to the base  107 . 
     In conclusion a junction box  100  is disclosed which facilitates an advantageous option for aligning the junction box  100  with reference to a gripper of an assembly robot or relative to the solar module through providing centering recesses. 
     REFERENCE NUMERALS AND DESIGNATIONS 
     
         
           10  junction box 
           11  housing 
           12  inner cavity 
           13  connecting contact 
           14  connecting conductor 
           15  plug connector 
           16  mechanism 
           17  support 
           18  spacer 
           19  body of  18   
           20  base 
           21  head 
           22  spacer 
           23  base disc 
           24  shoulder 
           25  rib 
           26  shoulder 
           27  support section of  21   
           28  conical circumferential surface of  27   
           29  stabilization wall 
           30  receiver of  20   
           31  inner circumferential surface of  18   
           32  wall surface of  29   
           33  longitudinal bore hole of  21   
           34  stop surface 
           35  star shaped groove 
           36  square groove 
           37  bore hole with larger diameter 
           38  annular surface of  17   
           39  hollow cylindrical section 
           40  cavity of  39   
           41  inner surface of  39   
           42  fit clearance 
           43  inner surface of  30   
       
    
     REFERENCE NUMERALS FOR FIGS.  12 - 14   
     
         
           100  junction box 
           101  housing 
           102  inner cavity 
           103  connecting contacts 
           104  centering recess 
           105  wall 
           106  centering boss 
           107  base of  104   
           108  slanted surface of  105   
           109  centering surface of  106   
           110  cuboid section 
           111  vertically declining wall sections of  105