Patent Publication Number: US-7220135-B1

Title: Printed circuit board stacking connector with separable interface

Description:
FIELD OF THE INVENTION 
   The enclosed embodiment depicts electrical connectors for interconnection to printed circuit boards, and in particular for stacked board to board interconnections. 
   BACKGROUND OF THE INVENTION 
   It is common to provide interconnections to and from printed circuit boards to other devices and or to other printed circuit boards. It is also common place to provide multi-layer printed circuit boards in specific applications. For example, it is common place to provide multi-layer stacked printed circuit boards in such instances as control technology where the boards are stacked one above the other in parallel manner in a closely spaced arrangement, with an insulator providing the insulative spacing between the two printed circuit boards. It is also common to provide printed circuit boards having a like array of plated through holes where the boards are interconnected at each plated through hole by a commoning connection at each of the plated through holes. 
   One such application has screw machined components having hexagonal, (or other multi-sided configuration) which are press-fit into one of the plated through holes and includes another pin or other interconnection device connected to the press-fit screw machined members. In such applications, the insertion forces for press fitting the screw machined components into the printed circuit board tend to be excessive and cause the screw machine contact and/or the printed circuit board to become damaged during the assembly. 
   These and other objects are to be accomplished with the following embodiments and teachings. 
   SUMMARY OF THE INVENTION 
   The objects were accomplished by providing a board to board interconnect assembly comprising a stamped and formed socket contact having a compliant portion for interconnection to a first printed circuit board plated throughhole and an integral socket portion. A stamped and formed pin contact has a compliant portion for interconnection to a second printed circuit board plated throughhole, and a pin portion for interconnection to the integral socket portion. 
   In another embodiment of the invention, a board to board interconnect assembly, comprises first and second printed circuit boards positioned in a spaced apart and parallel manner, each printed circuit board having an array of plated through holes, with the arrays in each board being in alignment. A stamped and formed socket contact has an integral socket portion and a compliant portion interconnected to the first printed circuit board plated throughhole. A stamped and formed pin contact has an integral pin portion and a compliant portion interconnected to a second printed circuit board plated throughhole. The pin portion projects through the first printed circuit board, and through the socket compliant portion, to interconnect the pin portion and socket portion. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of the components of the board to board interconnect shown in a space apart manner and poised for interconnection with each other; 
       FIG. 2  shows an underside perspective view of the socket assembly of  FIG. 1 ; 
       FIG. 3  shows a perspective view similar to that of  FIG. 2 , of the housing without the socket contacts; 
       FIG. 4  is an enlarged view of the portion denoted in  FIG. 3 ; 
       FIG. 5  is a cross-sectional view through lines  5 — 5  of  FIG. 4 ; 
       FIG. 6  is a perspective view of the socket contact of the present invention; 
       FIG. 7  is an enlarged view of the portion denoted in  FIG. 1 ; 
       FIG. 8  is an underside perspective of the pin assembly shown in  FIG. 1 ; 
       FIG. 9  is a perspective view of one of the pin contacts of  FIG. 8 ; 
       FIG. 10  is an enlarged view of the portion denoted in  FIG. 1 ; and 
       FIG. 11  is a cross-sectional view similar to that of  FIG. 1  showing the board to board inner connect in its fully mated condition. 
   

   DETAILED DESCRIPTION OF INVENTION 
   With reference first to  FIG. 1 , a board to board interconnect assembly is shown generally at  2  which includes a socket assembly  4 , having a socket housing  6  and a plurality of socket terminals  8 . The socket assembly  6  is shown poised for receipt and interconnection to, a printed circuit board  10 . Assembly  2  further includes a pin assembly  12  including a pin housing  14  and a plurality of pin terminals  16 . Pin assembly  12  is shown poised for receipt and interconnection to a printed circuit board  18 . 
   With reference now to  FIG. 2 , socket assembly  4  is shown in greater detail as including a plurality of columns and rows of socket terminals  8  defining an array of socket terminals. With reference to  FIGS. 3 and 4 , socket housing  6  is shown in greater detail where socket housing  6  is comprised an insulative plate member  20  having a plurality of openings at  22 . As shown in  FIG. 4 , openings  22  include a U-shaped portion at  24  and a flat sidewall portion  26 . As shown in  FIGS. 3–5 , openings  22  extend between an internal face  28  and an external face  30 . 
   With reference now to  FIG. 6 , socket terminals  8  are shown including compliant portions  32  integrally connected to socket portions  34  by way of an integral strap  36 . As shown, compliant portions  32  include a C-shaped cross section around a body portion  38  which necks down into lead in portions  40  as described herein. As also shown in  FIG. 6 , body portion  38  of compliant portion  32  includes an upper engaging surface  42  as will be described herein. Socket portion  34  includes a C-shaped retaining portion  46  having socket beams  50  extending downwardly from the retaining portion  46 . As shown socket beams are deflected inwardly to form a constricted portion between contact surfaces  52  of socket beams  50  and with a contact surface portion  54  of strap  36 . 
   Thus socket terminals  8  may be positioned in openings  22  with retaining portions  46  being positioned in openings  22 , and with the socket beams  50  depending downwardly as shown in  FIG. 7 . As also shown, body portion  38  is a larger diameter than opening  22  and thus engaging surface  42  abuts inner face  28  of socket housing  6 . 
   With respect now to  FIG. 8 , pin assembly  12  is shown with a plurality of pin terminals  16  positioned in a plurality of columns and rows defining an array of pin terminals  16 . It should be appreciated that the arrays of the pin terminals  16  and the array of socket terminals  8  are substantially identical in order to provide mating engagement between the two. It should also be appreciated that pin housing  14  is substantially identical to socket housing  6 , and therefore pin housing  14  will not be described in detail herein. 
   With respect now to  FIG. 9 , pin terminals  16  will now be described. Pin terminals  16  includes compliant portion  60  having a socket portion  62  integrally attached by way of strap portion  64 . Furthermore pin portion  66  is integrally attached to compliant portion  60  from the opposite end as the socket portion  62 . Socket portion  62  includes a C-shaped retaining portion  68  in the way of a compliant C-shaped member, having socket beams  70  extending downwardly therefrom. Socket portion  62  defines a three point contact by way of contact surfaces  72  of socket beams  70 , and by way of contact surface portion  74  on strap portion  64 . Furthermore, compliant portion  60  includes a body portion  80  of C-shaped configuration on the cross section together with a lead in portion at  82 , and an engaging portion at  84 . 
   Thus, as shown in  FIG. 10 , pin terminals  16  are situated in pin housing  14  with the C-shaped retaining portions  68  maintaining the pin terminals  16  in openings  22  with the compliant portion  60  and the pin portion  66  exterior to pin housing  14 , and with the engaging surface  84  in abutment with internal face  28 . Thus, it is the socket assembly  4  in the configuration of  FIG. 7  and the pin assembly  12  in the configuration of  FIG. 10  which allow for the interconnection of the two assemblies  4 ,  12  and the two printed circuit boards  10  and  18  to be interconnected together. As shown in  FIG. 1 , printed circuit board  10  includes a plurality of plated through holes  100  (only one of which is shown) however it should be appreciated that the through holes  100  have a like array as the array of socket terminals  8 . Furthermore circuit board  18  is shown poised over pin assembly  12  where printed circuit board  18  has a plurality of plated through holes  102  (only one of which is shown) for interconnection to pin assembly  12 .  FIG. 1  also shows multiple spacers such as  104  positioned between the two circuit boards  10 ,  18 . These spacers are intended to insulate the two boards  10 ,  18  and their components from each other. While shown as washers or grommets, it should be appreciated that this insulation could also be in the form of a sheet gasket, or any other spacer. 
   To make the interconnection, one of the boards  10  or  18  is positioned over its respective assembly  4  or  12 . For example, and with respect again to  FIG. 1 , printed circuit board  10  is positioned with the plurality of plated through holes  100  to be positioned over the compliant portions  32  which retains and electrically connects the socket terminals  8  to the plated through holes  100 . During insertion into the PCB, the lead-in portions ( 40 ) of the socket contact flare open to allow for ease of mating to pin ( 66 ). Meanwhile printed circuit board  18  can be positioned with the plated through holes over pins  66  and in interconnection with compliant portions  60  which causes pins  66  to project out of plated through holes  102 . As shown in  FIG. 11 , the two assemblies may now be brought together, such that pins  66  protrude into openings  44  ( FIG. 7 ) of the socket terminals  8  and the pin portions  66  extends upwardly through compliant portion  32 , to make contact with socket beams  50  and the kinked contact surface  54  ( FIG. 6 ). 
   Thus, a very inexpensive interconnect has been provided, for the placement of two printed circuit boards in a back to back manner for interconnecting the two boards together. It should also be appreciated from  FIG. 1 ,  10  or  11  that a further interconnection could be made with the socket beams  70  of pin terminal  16  for further electrical interconnection.